What Is the Difference Between 3G-SDI and HD-SDI

It is known that SDI interfaces can be roughly divided into three types: SD-SDI (270Mbp, SMPTE259M), HD-SDI (1.485Gbps, SMPTE292M) and 3G-SDI (2.97Gbps, SMPTE424M). It is seen from these standards of division that the rate is an important index. For HD-SDI and 3G-SDI, as the commonly-used two types in radio and television industry, maybe there are still many people unfamiliar with them and what difference between them. Then in this article, there will be an introduction to the difference between HD-SDI and 3G-SDI.

Before the introduction to HD-SDI and 3G-SDI, to understand them better, it will be better to know what SDI is. SDI (Serial Digital Interface) is a digital video interface standard made by SMPTE organization. This serial interface transmits every bit of data word and corresponding data through single channel. Due to the high data rate of serial digital signal (a kind of digital baseband signal), it must be processed before transmission.

What Is 3G-SDI?

3G-SDI has been widely used in the radio and TV industry. With the continuous development of the security industry, its advantages, high speed and without digital uncompressed, are gradually found. At present, a large number of 3G-SDI series products have been introduced in the market, including SDI conversion equipment, SDI digital switching matrix equipment and SDI distributor. These devices use 3G signals, and can also be compatible with 1.5G signals for long-distance transmission to meet the diverse needs of users.

What Is HD-SDI?

HD-SDI is a high-definition digital component serial interface. HD-SDI is high-definition radio and television camera which is real-time and uncompressed. It is another scientific and technological progress in the security monitoring field. It provides a high-definition image source for the monitoring center. The HD-SDI camera, based on the serial link standard of the SMPTE (film and television Engineer Association), is a high-definition and real-time video camera that transmits uncompressed digital video through 75 ohm coaxial cables.

What Is the Difference Between 3G-SDI and HD-SDI

The design and production of HD-SDI optical terminal equipment is suitable for serial digital optical transmission equipment with high reliability and high performance in the TV industry. The signal format is from 19.4Mbps to 1.485Gbps, and the system supports the signals with digital TV formats such as SMPTE292, SMPTE259M, SMPTE297M, SMPTE305M, SMPTE310M and DVB-ASI (EN50083-9), so as to satisfy the requirements of industrial products. 3G-SDI digital video optical terminal device with ultra high definition is an upgraded version of the HD-SDI optical terminal device. The signal format is from 19.4Mbps to 2.97Gbps, and the system is accorded with the signal of digital TV formats such as SMPTE424M, SMPTE292M, SMPTE259M, SMPTE297M, SMPTE305M, SMPTE310M, DVB-ASI (EN50083-9) and so on.

With the emergence of standard about high-definition(HD) video standards such as 1080i and 720P, the interface is adjusted to process higher data rate(1.485Gbps). The 1.485Gbps serial interface is usually called as HD-SDI interface, defined by SMPTE292M, and uses the same 75 ohm coaxial cable. SMPTE approves a new standard called as SMPTE424M, which doubles the SDI data rate to 2.97Gbps on the same 75 ohm coaxial cable. This new standard is also called 3-Gbps (3G) SDI, which supports higher-resolution image quality such as 1080P and digital cinema. At present, the highest rate of digital products is 7K-SDI.

Above all is about the difference between HD-SDI and 3G-SDI. For SDI series products, Gigalight currently has 3G-SDI SFP, 6G-SDI SFP+, 12G-SDI SFP+ optical transceiver. If you want to know more details, welcome to visit Gigalight official website.

About Gigalight:

Gigalight is a design innovator in global optical interconnect field. A series of optical interconnect products include: optical transceivers, passive optical components, active optical cables, GIGAC MTP/MPO cabling, cloud programmers & checkers, etc. Three applications are mainly covered: Data Center & Cloud Computing, MAN & Broadcast Video, and Mobile Network & 5G Optical Transmission. Gigalight takes advantage of its exclusive design to provide clients with one-stop optical network devices and cost-effective products.

Four Mainstream Applications of 100G and Their Features

At present, the application and technology of 100G have always been the focus of the industry, and the market of 100G can not be developed in the real sense due to some factors such as the cost in tech, efficiency, and market demands. However, with the gradual stabilization of 40G, the market of 100G has been slowly opened. Now there are many kinds of interface technology about 100G applications in the market. And then in this article, there will be an introduction to four mainstream applications of 100G and their features.

1. QSFP28 100G SR4 Optical Transceiver and Its Features

The wavelength of QSFP28 SR4 is 850nm, and the interface type is 12-fibers MPO (Intermediate 4-fibers channel is not activated). It is with 4 channels combined with 8-fibers multimode fiber, each channel supporting 25G to achieve 100G rate.

Features: the interface, same as that of QSFP-40G-SR4, can be directly upgraded from 40G  to 100G. The optical module is usually connected with OM3 and OM4 multimode fiber, respectively to support the transmission distance of 70 meters and 100 meters (the recently-published technology is possible to support  transmission distance of 200 meters via OM4 optic fiber).

2. QSFP28 100G PSM4 Optical Transceiver and Its Features

QSFP28 PSM4 transmission mode is similar to that of QSFP28 100G SR4. Each channel supports 25G in 4 channels. This optical module uses single-mode optic fiber as the transmission media and the wavelength is 1310nm.

Features: adopting the QSFP28 port, able to reach transmission distance of 500ms via the single mode optic fiber, which makes it have a certain advantage in the market.

3. QSFP28 100G CWDM4 Optical Transceiver and Its Features

The coarse wavelength division multiplexing technology and LC duplex interface are used with single-mode fiber, by which the maximum transmission distance can reach 2km. Its form factor is QSFP28. This optical module is cheaper than the traditional single-mode optical module.

Features: the coarse wavelength division multiplexing technology based on single-mode fiber has been relatively mature, but QSFP28 CWDM4 has not been formally approved by the IEEE standard group. Currently, the technology standard is unified and promoted by CWDM4 MSA.

4. QSFP28 100G SWDM4 Optical Transceiver and Its Features

SWDM(Short Wavelength Division Multiplexing)refers to the short wavelength division multiplexing technology that can transmit 4 bands of optical signals in multi-mode optical fiber with one fiber. The windows of these 4 bands are respectively 850nm, 880nm, 910nm and 940nm. The principle of this technology is similar to that of CWDM on single mode. But it is the first time that SWDM has applied WDM(Wavelength Division Multiplexing)technology to the short band of multimode optic fiber.

Features: 100GBase-SWDM4 optical module uses a multi-mode duplex LC interface. It just needs optic fiber with 2-fibers. It usually adopts OM4 optic fiber, the transmission distance can reach above 100m. If it uses WBMMF(WideBand Multi-Mode Fiber）, the transmission distance can reach 300m. Compared with SR4, SWDM4 requires only 25% of optic fibers.

In the current situation, the application mode of 100G is with at least 10 types. And the above-mentioned four types of interface technologies focus on that of data center applications. For more information about it, welcome to visit Gigalight official website(www.gigaligt.com).

About Gigalight:
Gigalight is a design innovator in global optical interconnect field. A series of optical interconnect products include: optical transceivers, passive optical components, active optical cables, GIGAC MTP/MPO cabling, cloud programmers & checkers, etc. Three applications are mainly covered: Data Center & Cloud Computing, MAN & Broadcast Video, and Mobile Network & 5G Optical Transmission. Gigalight takes advantage of its exclusive design to provide clients with one-stop optical network devices and cost-effective products.

An Analysis on Principles and Key Techs of 40G/100G Coherent Optical Communication

As the large-scale deployment of 40Gb/s is carried out, many new 100G/s code modulation formats have emerged in the industry. For various transmission code patterns with different features, based on the comprehensive consideration on parameters of other system design, comprehensive selections are made from perspectives of transmission distance, channel spacing, compatibility with 40Gb/s and 10Gb/s systems, costs of optical transceiver and transmission performance in the industry.

With the advancements of high-speed Digital Signal Processing (DSP) and Analog to Digital Conversion (ADC), coherent optical communication has become a research focus. The combination of coherent detection with DSP technology can make it to carry out carrier phase synchronization and polarization tracking in the electrical field, eliminating the two major obstacles of traditional coherent receiving. In addition, DSP is simple in structure of coherent receiving, with transparency in hardware, available to compensate various transmission losses in the electrical field, to simplify transmission link, to reduce transmission cost, as well as to support multi-ary modulation format and polarization multiplexing so as to realize high spectrum efficiency. After the research and development on the 100Gb/s module in the industry for one or two years, 100G/s coherent PM-QPSK is becoming the main option in the industry.

An Analysis On the Basic Principles of Coherent Optical Communication

Coherent optical communication system can divide the optical frequency bands into many channels, so that optical frequencies can be made full use of, namely multi-channel optical fiber communication. Coherent optical communication technology has the advantage of high receiving sensitivity. The receiving sensitivity of coherent detection technology is 18dB higher than that of direct detection technology.

In figure 1, the transmitter uses polarization multiplexing, the laser signal as a carrier is divided into two paths(X/Y path) through the PBS (Polarization Beam Splitter). Each signal respectively modulates 10.7/27.5Gb/s signal to the carrier by the I/Q modulator(the phase difference between I and Q path is 90 degrees) composed by two MZ modulators, then multiplexing optical signals on the X axis and Y axis into one by polarization multiplexer according to polarization multiplexing to transmit out via optic fiber. After that, the transmission of 40/100Gb/s on single-mode optic fiber can be achieved.

On the receiving end, different from the intensity modulation(direct detection system), the coherent optic fiber communication system adds the Local Oscillation(LO)light source that the heterodyne or homodyne receiving needs. The optical wave transmitted out by the light source and modulated optical wave take optoelectronic mixing under the condition of wavefront matching and the polarization matching. Slight change on optical frequency of the local oscillator can change the selected channel, so the requirements for line width of local oscillator are high. The field intensity of signal optical wave output after mixing is proportional to the square of the sum of LO optical wave's field intensity, from which the difference-frequency signal between LO optical wave and signal optical wave can be selected out. On account that the change rule of the difference-frequency signal is same as that of signal optical wave, unlike direct detection wave mode in which the detection current only reflects the intensity of the light wave. Therefore, various modulation modes, such as amplitude, frequency, phase and polarization, can be realized.

In the coherent detection method of receiver in Figure 2, due to the detection on the signal of polarization multiplexing, the received signal is decomposed into two orthogonal signals via a PBS (Polarization Beam Splitter); each orthogonal signal is mixed with a LO light source, and the control accuracy of LO light source's carrier frequency is at hundreds of KHz. After mixing, 4 optical signals with polarization and phase orthogonality are received, respectively detected by PIN. After electrical amplification and filtering, they will be converted into 4 channels of digital electrical signals via the A/D circuit. Digital electrical signal realizes these functions by the way of Digital Signal Processing (DSP) chip digital equalization, such as timing recovery, signal recovery, polarization and PMD tracking, and dispersion compensation.

Main Advantages of Coherent Optical Communication

Coherent optical communication takes full advantage of coherent communication mode's features, such as the mixing gain, excellent channel selectivity and tunability and so on. Compared with IM/DD system, coherent optical communication system is with the following unique advantages:

1. With High Sensitivity and Long Relay Distance

One of the most important advantages of coherent optical communication is coherent detection, which improves the sensitivity of the receiver. In coherent optical communication system, the output photocurrent after coherent mixing is proportional to the product between optical power of signal and that of the LO. Under the same conditions, the sensitivity of coherent receiver is higher 18dB than that of common receiver, which can reach the high performance close to the limitation of shot noise. Simultaneously, the transmission distance without relay of the optical signal can be extended.

2. With High Selectivity and Large Communication Capacity

Another main advantage of the coherent optical communication is that the selectivity of receiver can be improved. In direct detection, the receiving band is relatively large. To suppress noise interference, the narrow band filter is usually set in front of the detector, but the frequency band is still very wide. In the process of coherent heterodyne detection, what is detected is mixing light of the signal light and the LO light. Therefore, only noises in the medium-frequency band can enter into the system, while other noises are filtered by microwave and medium-frequency amplifier with narrow bandwidth. It can be seen that heterodyne detection has good filtering performance, which will play a significant role in the application of coherent optical communication. In addition, due to the good wavelength selectivity of coherent detection, the coherent receiver can greatly reduce the frequency interval in the frequency division multiplexing system so as to replace the large frequency interval of the traditional optical multiplexing technology, which is with the potential advantage of realizing higher transmission rate by frequency division multiplexing.

If the transmission function of the medium-frequency filter in the coherent optical communication of heterodyne detection is just contrary to that of the optical fiber, the effect of the optic fiber dispersion on the system can be reduced.

An Analysis On Key Technologies of Coherent Optical Communication

1. Light Source Technology

In the coherent optical communication system, the requirements for signal light source and LO light source are relatively high. It requires narrow spectral line and frequency’s high stability. The line width of light source will decide the minimum error code rate that the system can reach. In the meantime, the frequency of the semiconductor laser is very sensitive to the changes of working temperature and the injection current(the variation is generally at dozens of GHz/℃ and dozens of GHz/mA). Therefore, except to keep injected current and temperature stable, the measures are also taken to keep optical frequency stable.

2. Receiving Technology

The receiving techs of coherent optical communication include two parts: one is the optical receiving tech; another one is the demodulation tech with various formats after intermediate frequency.

The Balanced Receiving Method: in the FSK system, it is unavoidable to produce extra noises from amplitude modulation in the modulation process of the semiconductor laser, and the noise can be reduced by using the balanced receiving method. The main concept of the balance method is that after the optical signal enters from the optic fiber, the local-oscillation light is controlled by polarization to ensure that it is adapted to the polarization state of the signal. The local-oscillation light and the signal light, passing the direction combiner at the same time, are divided into two paths, respectively input into two identical PIN photodetectors. After that, what the two optoelectronic detectors output is envelope signal with equal amplitude and inverse phase. After these two signals are synthesized, frequency-modulated signal is increased by one time, while the noises from parasitic amplitude modulation offset with each other to meet the requirements of eliminating effects from amplitude modulation noises.

Polarization Control Technology: in the system of coherent optical communication, the polarization of the signal light and local-oscillation light is definitely required in the same deviation, so as to achieve a good mixing effect and to improve the quality of the receiving. But the polarization state is unstable when the signal light is transmitted at long distance via single-mode optic fiber. To solve the problem, various methods are proposed, such as the adoptions of polarization-maintaining optic fiber, polarization controller and polarization diversity receiving, etc. When the light is transmitted in the common optic fiber, the phase and the polarization plane will be randomly changed. The polarization-maintaining optic fiber is a special fiber that keeps the optical phase and polarization constant by selecting techniques and materials, but this type of optic fiber is with high loss and high cost. The polarization controller is mainly to keep signal light and local oscillation light in the same deviation, but the response speed of this method is slow and the requirements for the loop control is also higher. In the polarization diversity receiving, after the mixing of signal light and local oscillation light, hybrid light is divided into two vertical polarization components by the polarization splitting element. The two vertical polarization components of local oscillation light is controlled by polarization controller, which keeps the power of two components equal. The random fluctuation of polarization in the signal light may cause the fading of medium-frequency signal in one of the branches, but the medium-frequency signal in another branch still exists. Thus, the received demodulation signal almost has nothing to do with polarization of signal light. The response speed of this tech is relatively quick. Simultaneously, it is practical, but complex to achieve.

3. External Optical Modulation Technology

In the process of the direct modulation on a certain parameter of a semiconductor laser's optical carrier, the parasitic oscillation of other parameters will always be incidental. For example, the ASK direct modulation is with the change of the phase, and the modulation depth will also be limited. In addition, the problems will also appear such as unstable frequency and late oscillation. Therefore, in coherent optical communication system, except that FSK can adopt direct injection current to operate frequency modulation, and others adopt external optical modulation.

4. Nonlinear Crosstalk Control Technology

In coherent optical communication, dense frequency division multiplexing is often used. Therefore, the nonlinear effect in the optic fiber may make the signal intensity and phase in some channel of coherent optical communication influenced by signals of other channels, so as to form a nonlinear crosstalk.

Conclusion

In recent years, a great progress has been made in optical devices. Thereinto, these have been greatly improved, such as the output power, line width, stability and noise of the laser, as well as the bandwidth of the photodetector, the power capacity and the common-mode rejection ratio rate. Meanwhile, the performance of microwave electronic devices has been also greatly improved. These advancements make the commercialization of coherent optical communication system possible.

Article Source: www.gigalight.com

About Gigalight:

Gigalight is a design innovator in global optical interconnect field. A series of optical interconnect products include: optical transceivers, passive optical components, active optical cables, GIGAC MTP/MPO cabling, cloud programmers & checkers, etc. Three applications are mainly covered: Data Center & Cloud Computing, MAN & Broadcast Video, and Mobile Network & 5G Optical Transmission. Gigalight takes advantage of its exclusive design to provide clients with one-stop optical network devices and cost-effective products.

An Introduction to SDI Video SFP: Definition, Types, Applications

Video optical transceivers are primitively used in radio and television industry. It mainly includes two series: video SFP module or video SFP+ transceiver. Then today’s topic will be involved in types and applications of SDI video SFP optical transceiver in this post.

The Definition of SDI Video SFP

SDI SFP optical module and its related products are initially designed for the radio and television industry, applied for television studio, animal filming, film shooting, large sports events live. It is extended to the 1080 PHD monitoring field. SDI SFP optical module is usually used on the SDI interface of the HD-SDI terminal device. The transmission rate and frequency for each different SDI interface are different.

Types of SDI SFP Optical Transceiver

SDI Video SFP transceivers can be divided into various types according to different factors. For example, on the basis of operating wavelength, they can be divided into 1310nm, 1490nm, 1550nm and CWDM wavelengths video SFP transceivers; based on transmission distance, there are 300m, 2km, 10km, 20km, 40km; based on operating rate, there are usually 3G-SDI, 6G-SDI and 12G-SDI video SFP optical transceivers.

3G-SDI video SFP optical transceivers have a data rate up to 3Gbps, which are specifically designed for high performance in the presence of SDI pathological patterns for SMPTE 259M, SMPTE 344M, SMPTE 292M and SMPTE 424M serial rates. They are generally used for television broadcasting. However, as technology advances, they are now also widely applied in global security applications such as high-end surveillance or unmanned systems, allowing simple designs or upgrades with full HD cameras.

6G-SDI video SFP optical transceivers’ data rate is intended to be twice as fast as 3G-SDI optical modules, which means it is supposed to deliver a payload of 6Gbps. Therefore, they are not only designed for SDI pathological patterns for SMPTE 259M, SMPTE 344M, SMPTE 292M and SMPTE 424M serial rates but also for SMPTE 2081. 6G-SDI video SFP optical transceivers are often used in camera, video, security monitoring applications and 4K /HDTV/SDTV service interfaces.

Speed up to 12Gbps, 12G-SDI video SFP transceivers are specifically designed for high performance in the presence of SDI pathological patterns for SMPTE 259M, SMPTE 344M, SMPTE 292M, SMPTE 424M, ST2081 and ST-2082 serial rates. They are mainly used for SMPTE ST-297-2006, ST-2081 and ST-2082 compatible electrical-to-optical interfaces and UHDTV/HDTV/SDTV service interfaces.

Applications of SDI SFP Optical Transceiver

1. Applied in HD Camera or Monitor System

There are usually multiple HD end-devices in HD camera or monitor system. Therefore, one HD video matrix can be used as one end which provides multiple video SFP ports, and multiple HD-SDI equipments can be used as the other ends. 3G-SDI SFP transceiver is plugged into the equipment respectively, then SDI SFP transceivers on both ends are connected via fiber optic cables.

2. Applied for Broadcast Video Transmission

Broadcast video transmission needs high-density cabling. Thus, HD-SDI equipment with high-density video SFP ports is needed.

In Conclusion

Above all is about the introduction to types and applications of video SFP module, hoping this article can be helpful to those who want to know more about video SFP transceiver. In addition, for above-mentioned two series of video optical transceivers, Gigalight currently has these types: 3G-SDI SFP, 6G-SDI SFP+, 12G-SDI SFP+. For more details, pls visit Gigalight official website.

About Gigalight:

Gigalight is a design innovator in global optical interconnect field. A series of optical interconnect products include: optical transceivers, passive optical components, active optical cables, GIGAC MTP/MPO cabling, cloud programmers & checkers, etc. Three applications are mainly covered: Data Center & Cloud Computing, MAN & Broadcast Video, and Mobile Network & 5G Optical Transmission. Gigalight takes advantage of its exclusive design to provide clients with one-stop optical network devices and cost-effective products.

Do You Know These about Cloud Computing Data Center?

With the increasing of enterprise informatization application system, the space, electricity distribution system and air conditioning refrigeration of data centers tend to be saturated. Simultaneously, the utilization rate of the servers is generally low. In order to solve the contradiction between the development of data center and the rapid growth of information resources, the concept of cloud computing and the virtualization technology provide the means to optimize the traditional data center. Therefore, cloud computing data center appears. Then in this article, there will be an overview of cloud computing data center.

Before coming into today's topic, it will be better to have a knowledge of some information about cloud computing and traditional data center, by which you will find what relations exit between cloud computing and data center. Simultaneously, it also will be helpful for you to know cloud computing data center better in the following introduction to it.

What Is Cloud Computing?

Cloud computing is divided into public cloud, private cloud and hybrid cloud. Cloud computing refers to the delivery and utilization modes of information technology infrastructures in a narrow meaning; while it means that the delivery and use patterns of services in a broad meaning. Cloud computing has 3 service modes: IaaS, PaaS, and SaaS.

What Is the Traditional Data Center?

The traditional data center is the generic term of all IT devices and information systems in the network center. It provides information services for the enterprises or the public through the network. The information system contributes to the standardization of business process and the improvement of operation efficiency for the enterprises. The data center provides a stable and reliable infrastructure and running conditions for the information system, also ensures the convenient maintenance and management of the information system.

An Overview of Cloud Computing Data Center

1. What Is the Cloud Computing Data Center?

80% of cloud computing data centers in enterprises are generally deployed with private cloud. Cloud computing data center refers to the data center optimized by the means of application virtualization.

2. The Structure of Cloud Computing Data Center

The structure of cloud computing is divided into two parts: service and management. In the aspect of service, it mainly focuses on providing various services based on cloud, which includes 3 levels: Infrastructure as a Service(IaaS), Platform as a Service(PaaS), and Software as a Service(SaaS).

3. The Constructions of Cloud Computing Data Center

The core technology of cloud computing data center is the virtualization technology. The main objects of virtualization are servers, storage, network and desktop. Thus, a brand new mode to deploy and manage data center is formed. In fact, 3-clouds resources and services need to be constructed.

• The Construction of IaaS

The infrastructure layer, based on the IT resources, includes the collection of hardware resources and related management functions after virtualization. The delivery of infrastructure services to users is the most fundamental infrastructure resources, providing users with virtualized computing resources, storage resources and network resources.

• The Construction of PaaS

Platform layer, based on platform service and middleware, provides middleware and basic services related to application development, deployment and operation, which can better meet the requirements of cloud applications in scalability, availability, and security.

• The Construction of SaaS

Application layer is a collection of application software on the cloud, which are built on the environments provided by the resource and platform layer from infrastructure layer and delivered to the users through the network.

4. The Advantages and Influences of Cloud Computing Data Center

• Improving the Utilization Rate of Resources

Compared with the traditional data center, the cloud computing platform provides flexible services that can dynamically allocate and release resources in a large pool of resources according to the demands of users, without the need to reserve peak resources for each user, so that the utilization rate of resources can be greatly improved. In addition, there are more users in the cloud data center, then the cost to improve energy efficiency is relatively lower. After that, the cost can be apportioned to more servers.

• Flexible to Extend Resources and to Improve the Reliability

The "cloud" resources applied by users can be adjusted and dynamically expanded according to the requirements of their applications, able to effectively meet the needs of large-scale growth of applications and users.

• The Data Centers of Small Enterprises Are Gradually Weaken

After entering into the era of cloud computing, IT has transformed from the self-sufficient workshop mode at early period to the industrialized operation mode with a scale effect. Some small-scale data centers personally owned by enterprises will be eliminated, and the data centers with large scale and reasonable configuration resources will take place of them.

• More Specific in Specialized Responsibility Division

Cloud computing data center is larger-scale, and more specialized than data centers with small/medium scale, higher management level. In addition, it can also provide lower cost needed by unit calculation. Therefore, the costs taken in labours can be cut down to a large extent, and the specialized responsibility division is more specific.

Conclusion

The way to upgrade traditional data centers is found by the analysises on cloud computing and virtualization tech. This makes it possible to implement application, develop the new-generation data center to save resources and reduce power dissipation.

Article Source: Gigalight official website (www.gigalight.com).

About Gigalight:
Gigalight is a design innovator in global optical interconnect field. A series of optical interconnect products include: optical transceivers, passive optical components, active optical cables, GIGAC MTP/MPO cabling, cloud programmers & checkers, etc. Three applications are mainly covered: Data Center & Cloud Computing, MAN & Broadcast Video, and Mobile Network & 5G Optical Transmission. Gigalight takes advantage of its exclusive design to provide clients with one-stop optical network devices and cost-effective products.

What Are Types of SDI Video SFP Optical Transceiver?

SDI optical transceivers are known to many people, initially applied in the radio and television industry. SDI series optical modules include many types, such as SDI SFP optics(mainly includes 3G-SDI Video SFP, 6G-SDI Video SFP, 12G-SDI Video SFP), SDI SFP+ optical module(mainly includes 3G-SDI Video SFP+, 6G-SDI Video SFP+, 12G-SDI Video SFP+), etc. Then today we will talk about types of SDI video SFP optical transceivers.

What Is SDI Video SFP Optical Transceiver?

SDI SFP optical module and its related products are initially designed for the radio and television industry, applied for television studio, animal filming, film shooting, large sports events live. It is extended to the 1080 PHD monitoring field. SDI SFP optical module is usually used on the SDI interface of the HD-SDI terminal device. The transmission rate and frequency for each different SDI interface are different.

An Introduction to Types of SDI Video SFP Optical Transceiver

SDI Video SFP transceivers can be divided into various types according to different factors. For example, on the basis of operating wavelength, they can be divided into 1310nm, 1490nm, 1550nm and CWDM wavelengths video SFP transceivers; based on transmission distance, there are 300m, 2km, 10km, 20km, 40km; based on operating rate, there are usually 3G-SDI, 6G-SDI and 12G-SDI video SFP optical transceivers.

3G-SDI video SFP optical transceivers have a data rate up to 3Gbps, which are specifically designed for high performance in the presence of SDI pathological patterns for SMPTE 259M, SMPTE 344M, SMPTE 292M and SMPTE 424M serial rates. They are generally used for television broadcasting. However, as technology advances, they are now also widely applied in global security applications such as high-end surveillance or unmanned systems, allowing simple designs or upgrades with full HD cameras.

6G-SDI video SFP optical transceivers’ data rate is intended to be twice as fast as 3G-SDI optical modules, which means it is supposed to deliver a payload of 6Gbps. Therefore, they are not only designed for SDI pathological patterns for SMPTE 259M, SMPTE 344M, SMPTE 292M and SMPTE 424M serial rates but also for SMPTE 2081. 6G-SDI video SFP optical transceivers are often used in camera, video, security monitoring applications and 4K /HDTV/SDTV service interfaces.

Speed up to 12Gbps, 12G-SDI video SFP transceivers are specifically designed for high performance in the presence of SDI pathological patterns for SMPTE 259M, SMPTE 344M, SMPTE 292M, SMPTE 424M, ST2081 and ST-2082 serial rates. They are mainly used for SMPTE ST-297-2006, ST-2081 and ST-2082 compatible electrical-to-optical interfaces and UHDTV/HDTV/SDTV service interfaces.

Above all is about the introduction to types of SDI video SFP optical transceiver. For above mentioned SDI video optical transceiver, Gigalight is currently with 3G-SDI SFP, 6G-SDI SFP+, 12G-SDI SFP+ optical transceiver. If you want to know more details of products, pls visit Gigalight official website.

About Gigalight:
Gigalight is a design innovator in global optical interconnect field. A series of optical interconnect products include: optical transceivers, passive optical components, active optical cables, GIGAC MTP/MPO cabling, cloud programmers & checkers, etc. Three applications are mainly covered: Data Center & Cloud Computing, MAN & Broadcast Video, and Mobile Network & 5G Optical Transmission. Gigalight takes advantage of its exclusive design to provide clients with one-stop optical network devices and cost-effective products.

What Are the Differences Between QSFP28 4WDM and QSFP28 CWDM4 Optics?

Both 4WDM and CWDM4 belong to 100G QSFP28 series optical transceiver, and are certainly related to WDM (wavelength division multiplexing)tech. Maybe there are still people confused of what differences between QSFP28 4WDM and QSFP28 CWDM4 optical transceiver are. Then in this article, a comparison between them will be made by Gigalight.

An Introduction to QSFP28 4WDM Optical Transceiver

4WDM(4-Wavelength Wavelength Division Multiplexing) optical module is defined by 4WDM MSA, targeted for longer reaches, lower costs, and lower power consumption, smaller form factor(QSFP28 form factor is usually preferred). 100G QSFP28 4WDM optics have three specifications including 100G QSFP28 4WDM-10, 100G QSFP28 4WDM-20, 100G QSFP28 4WDM-40. QSFP28 4WDM-10 is one type of 100G (4x25G) optical transceivers for the 10 km based on the CWDM4 wavelength grid; QSFP28 4WDM-20 and QSFP28 4WDM-40 are types of 100G (4x25G) optical transceivers respectively for 20kms and 40kms based on the LAN-WDM wavelength grid over duplex single-mode fiber (SMF). With respect to the benefits of 4WDM, its main advantages are lower in cost and power dissipation, and longer in transmission distance.

An Introduction to QSFP28 CWDM4 Optical Transceiver

The QSFP28 100G CWDM4 optical transceiver is a full duplex, photonic-integrated optical transceiver module that provides a high-speed link with a maximum transmission distance of 2km for 100G Ethernet. 100G QSFP CWDM4 is designed for optical communication applications compliant with the QSFP MSA, CWDM4 MSA and portions of IEEE P802.3bm standard. CWDM4 interfaces with LC duplex connectors. It converts 4 input channels of 25Gb/s electrical data to 4 channels of CWDM optical signals and then multiplexes them into a single channel for 100Gb/s optical transmission. Specifically speaking, four lanes with center wavelengths of 1270nm, 1290nm, 1310nm and 1330nm are controlled on the transmitting end. On the receiving end, four lanes of optical data streams are optically de-multiplexed by an integrated optical demultiplexer. With an optical multiplexer and de-multiplexer, one just uses a duplex single-mode fiber to connect two CWDM4 QSFP28 optical transceivers.

QSFP28 4WDM vs. QSFP28 CWDM4: What Are the Differences?

QSFP28 100G CWDM4 and QSFP28 4WDM are defined with different distances(respectively are 2km/10km/20km/40km) and wavelengths(respectively are CWDM wavelength and LAN WDM wavelength). 2km and 10km use CWDM wavelength. 20km and 40km use LAN WDM wavelength.

 

With the different size of the CWDM and LAN WDM wavelengths, the wavelength-transmitting TOSA for LAN WDM must be carried with a TEC (Thermo Electric Cooler). As the stable wavelength drifts with temperature, TEC consumes an extra 0.5W of power, so the overall power consumption of optical transceivers with LAN WDM wavelengths will be higher than that of CWDM optical transceivers. More differences between 100G QSFP28 CWDM4 and 100G QSFP28 4WDM are as follows:

 

By above comparison of QSFP28 CWDM4 and QSFP28 4WDM optical transceiver, the difference between them are very apparent. For QSFP28 4WDM series optical module, Gigalight has currently pushed out 100G QSFP 4WDM-40 and 100G QSFP 4WDM-20 optical transceiver module, but the 100GE 4WDM-40 QSFP28 optics is the key one for promotion at present. If you want to know more information about the products, pls visit Gigalight official website(www.gigalight.com).

Three Specifications of 100G QSFP28 4WDM Optics: 4WDM-10, 4WDM-20, 4WDM-40

To satisfy the increasing demands on more-cost-effective and lower-power-consumption 100G optical networks, 100G QSFP28 4WDM optical transceivers emerge in the market. 100G 4WDM series optical module currently includes three specifications in total: 100G QSFP28 4WDM-10, 100G QSFP28 4WDM-20, 100G QSFP28 4WDM-40. Today, in this article, Gigalight will mainly introduce them for you.

Before coming into today's topic, it will be better to have a knowledge of the MSA(Multi-Source Agreement) of these three specification optical transceivers: 4WDM MSA.

What Is 4WDM MSA(Multi-Source Agreement)?

The 4WDM MSA is an industry consortium dedicated to defining optical specifications and promoting adoption of interoperable 100G (4x25G) optical transceivers for 10 km based on the CWDM4 wavelength grid, and for 20 km and 40 km based on the LAN-WDM wavelength grid, over duplex single-mode fiber (SMF). These extended reaches are important for modern datacenter interconnects and mobile backhaul applications. The 4WDM MSA participants are responding to previously unmet industry needs for longer reaches, lower costs, and lower power consumption, as compared to previously available standards, in small form factors.

Introductions to Three Specifications of 4WDM Optics

The 100G QSFP28 4WDM-10 is based on the CWDM4 wavelength grid. To some degree, the QSFP28 4WDM-10 technical specification leverages the success of the CWDM4 2 km specification that has found broad acceptance in its target datacenter market. Like 100G QSFP28 CWDM4, the 100G-4WDM-10 specification employs 4 lanes of 25Gb/s using Coarse Wavelength Division Multiplexing (CWDM) technology to transport 100G optical traffic across duplex single mode fiber (SMF). Both specifications take advantage of Forward Error Correction (FEC) on the host port, in accordance with IEEE 802.3bj KR4 RS FEC. One key advantage of CWDM is that the lasers do not need to be cooled or temperature controlled, resulting in lower power consumption and simplicity of manufacturing. 100G QSFP 4WDM-10 optical module shares these advantages and furthermore are specified to be fully interoperable with CWDM4 products. The 100GE 4WDM-10 QSFP28 specification does not restrict the form factor although high-density QSFP28 modules are expected to be dominant.

100G QSFP28 4WDM-20 and 100G QSFP28 4WDM-40 are added on the basis of the 100G 4WDM-10. They employ LAN-WDM wavelength grid on the basis of IEEE 100GBASE-LR4 and ER4, over duplex single-mode fiber (SMF). Simultaneously, they also utilize the IEEE 802.3 KR4 RS FEC used on the host interface to reduce the cost.

This specification defines 4 x 25Gbps Local Area Network Wavelength Division Multiplex (LANWDM)optical interfaces for 100Gbps optical transceivers for Ethernet applications including 100GbE. Forward Error Correction (FEC) is a link requirement in order to ensure reliable system operation. Two optical transceivers communicate over single mode fibers (SMF) of length from 2 meters to at least 20 or 40 kilometers. The transceiver electrical interface is not specified by this MSA but can have, for example, four lanes in each direction with a nominal signaling rate of 25.78125Gbps per lane.

In addition, the QSFP28 4WDM-20 specification, which is an extension of the 100G-4WDM-10 10 km specification, enables customers to increase their reach using the same kind of optical components as 100GBASE-LR4 products. Similarly, the QSFP28 4WDM-40 enables 40 km reach with lower power consumption and in a smaller form factor than existing 100GBASE-ER4 compliant products that utilize a power-hungry SOA (Semiconductor Optical Amplifier).

For above-mentioned three specifications, Gigalight currently has these two: 100G QSFP 4WDM-20 and 100G QSFP 4WDM-40 optical transceiver, but the QSFP28 4WDM 40km optical transceiver module(shown as the pic) is the main one for promotion at Gigalight. For more information is at Gigalight official website.

About Gigalight:

Gigalight is a design innovator in global optical interconnect field. A series of optical interconnect products include: optical transceivers, passive optical components, active optical cables, GIGAC MTP/MPO cabling, cloud programmers & checkers, etc. Three applications are mainly covered: Data Center & Cloud Computing, MAN & Broadcast Video, and Mobile Network & 5G Optical Transmission. Gigalight takes advantage of its exclusive design to provide clients with one-stop optical network devices and cost-effective products.

Why to Use DWDM System in MAN and What Are Its Networking Schemes?

On account that DWDM (Dense Wavelength Division Multiplexing) technology can make full use of the huge bandwidth resources of optical fiber, greatly increasing the transmission capacity of the system and reducing the transmission cost, the technology has been widely used in the large-capacity transmission of long distance network and backbone network. If DWDM technology is introduced into the metropolitan area network and access network, the whole network will become a whole of seamless connection, providing support and connection for all different services. Therefore, the DWDM system in the metropolitan area network has great superiority and development potential, which will become the inevitable evolution of the whole communication network to the all-optical network.

Why to Use DWDM System in the Metropolitan Area Network(MAN)?

In the past, the SDH (Synchronous Digital Hierarchy)/SONET(Synchronous Optical Network) is the core component of the metropolitan area network. However, this technology is with limitations. For example, it is highly structured, simplex in interface and limited on bandwidth; simultaneously, it also can not meet the diverse needs of enterprises; in addition, its cost is relatively high in the installation and operation of Ethernet by SDH/SONET technology.

DWDM technology is an alternative solution of SDH/SONET technology. It is with flexibility and wide application. The DWDM system can carry SDH, PDH, and other unrestricted digital signals or analog signals. Therefore, vendors and enterprises can use DWDM technology to provide a variety of services. The metropolitan area network based on DWDM technology can make full use of the huge bandwidth resources of optical fiber, greatly improving the transmission capacity of the system and reducing the transmission cost.

Factors to be Considered for the Application of DWDM in the MAN

The application of DWDM technology in metropolitan area network is mainly determined by 3 factors: market demand, technology development and operation cost. Market demand is the fundamental reason for the entry of DWDM technology into the metropolitan area network; the tech factor is the effective guarantee for DWDM technology to enter the metropolitan area network. The cost of DWDM is also an important consideration factor for operators to adopt DWDM. Analyzing the particularity of the metropolitan area network and improving the DWDM system to reduce the price, it is the key of the DWDM technology to gradually penetrate into the metropolitan area network&access network from the backbone network, and finally to realize the all-optical-network.

Networking Scheme of DWDM in the MAN

MAN is generally divided into metropolitan core network and metropolitan access network. Metropolitan core network mainly takes 2.5Gb/s SDH as the integrated transmission platform, which will be gradually evolved in the DWDM integrated transmission platform. According to different development stages and different application fields, DWDM mainly has three application solutions. The three basic solutions match with different superstructure schemes, which can constitute various metropolitan core schemes to adapt to application conditions and development requirements of different operators.

1. DWDM Optical Multiplexing Scheme

DWDM as the multiplexing tech is introduced into metropolitan core network, only taking optical wavelength as the virtual optic fiber to solve the tense situation of optic fiber. Currently, DWDM MAN device enters into the market basically in this method. Because of the lack of path selection, monitoring and survivability processing in the WDM optical layer, the scheme still takes SDH as the integrated transmission network platform.

2. DWDM Configurable Halo Scheme

With the continuous introduction of the DWDM optical multiplexing system in the metropolitan core network and the practicability of the configurable OADM, DWDM configurable halo scheme of the metropolitan core network can be formed by combining configurable OADM system with DWDM system. This scheme greatly enhances the function of the WDM optical layer. OADM can be configured selectively up/down/direct connection with the optical wavelength so as to achieve fast protection switching and configuration. The DWDM configurable halo scheme enables DWDM to replace SDH as a multi-services platform. It also supports various protocols and services through a single and public metropolitan core integrated transmission platform based on DWDM, and it is with these advantages such as forward compatibility (such as SDH over WDM), reducing costs (by simplifying the network hierarchy structure, reducing equipment and improving transmission efficiency), simplifying network management and improving the flexibility of network configuration.

3. DWDM Mesh Network Scheme

After the OXC with wavelength switching/routing function is put into practical application, OXC can be introduced to constitute a more complex mesh network structure on the basis of DWDM configurable halo. OXC or wavelength router is very flexible. Common OXC nodes can contain the up/down optical paths and protection function of OADM in the chain/ring structures, and can reconfigure OXC to gradually develop toward multi-rings or pure mesh network structure without interrupting the services.

Conclusion

DWDM has been widely applied in the long-haul trunk line. In MAN, due to high cost of devices, immature tech, poor compatibility of devices, etc, DWDM is still hard to be widely applied in the MAN. But with the further development of market and the advancement of tech, new MAN devices with low cost will be developed for application on account that DWDM tech is with economic efficiency in capacity expansion, good extensibility, transparency in bite rate and protocol, and also is able to provide improved service quality. Therefore, DWDM tech is with a bright prospect in the MAN.

Article Source: Gigalight official website(gigalight.com)

About Gigalight:Gigalight is a design innovator in global optical interconnect field. A series of optical interconnect products include: optical transceivers, passive optical components, active optical cables, GIGAC MTP/MPO cabling, cloud programmers & checkers, etc. Three applications are mainly covered: Data Center & Cloud Computing, MAN & Broadcast Video, and Mobile Network & 5G Optical Transmission. Gigalight takes advantage of its exclusive design to provide clients with one-stop optical network devices and cost-effective products.

QSFP28 CWDM4 vs. QSFP28 PSM4: Which One Is Better?

Although a series of 200G or even 400G optical transceiver products emerge in the optical communication market, and they have not yet been put into commecial use currently due to that they are still in the stage of preparation in some aspects. Thus, 100G optical transceiver modules, especially QSFP28 PSM4 and QSFP28 CWDM4, are still spoiled in various application fields. Well, for these two optical transceivers, what are their differences and which one is better? The answers will be found in this article.

A Brief Introduction to QSFP28 PSM4 Optical Transceiver

PSM4, the abbreviation of Parallel Single Mode 4-channels, a optics with parallel technology, defined by the 100G PSM4 MSA(Multi-Source Agreement). It uses four lanes of parallel single fiber to deliever serialized data at a rate of 25Gbps per lane. 100GE PSM4 QSFP28 will be the optical transceiver that enables single-mode fiber to become popular in next-generation data centers due to its low cost and high configurability. It doesn’t need a MUX/DEMUX for each laser but it does need a directly modulated DFB laser (DML) or an external modulator for each fiber. QSFP28 100G PSM4 uses eight fibers, in which four fibers are for transmitting and four fibers are for receiving. A PSM4 QSFP28 optical module supports link lengths of up to 500 meters over single-mode fiber with 12 fiber MTP/MPO connectors. The light source of QSFP 100G PSM4 optic module is a single uncooled distributed feedback (DFB) laser operating at 1310nm.

A Brief Introduction to QSFP28 CWDM4 Optical Transceiver

The QSFP28 100G CWDM4 optical transceiver is a full duplex, photonic-integrated optical transceiver module that provides a high-speed link with a maximum transmission distance of 2km for 100G Ethernet. 100G QSFP CWDM4 is designed for optical communication applications compliant with the QSFP MSA, CWDM4 MSA and portions of IEEE P802.3bm standard. CWDM4 interfaces with LC duplex connectors. It converts 4 input channels of 25Gb/s electrical data to 4 channels of CWDM optical signals and then multiplexes them into a single channel for 100Gb/s optical transmission. Specifically speaking, four lanes with center wavelengths of 1270nm, 1290nm, 1310nm and 1330nm are controlled on the transmitting end. On the receiving end, four lanes of optical data streams are optically de-multiplexed by an integrated optical demultiplexer. With an optical multiplexer and de-multiplexer, one just uses a duplex single-mode fiber to connect two 100G CWDM4 optical transceivers.

QSFP28 CWDM4 vs. QSFP28 PSM4: Which One Is More Cost-Effective?

After knowing the basic information of PSM4 QSFP28 and CWDM4 QSFP28 optical transceiver, the comparison between them will be made in the following content to know which one is better. It is mainly made from perspectives of similarities and differences, shown as below:

Similarities of QSFP28 CWDM4 and QSFP28 PSM4 Optical Transceiver:

Optic Fiber Types: Both 100G QSFP CWDM4 and 100G QSFP PSM4 use single-mode fiber to transmit.

The Number of Lane: Both of 100G QSFP28 CWDM4 and 100GE PSM4 QSFP28 use 4 lanes(4×25Gbps) to achieve 100Gbps.

Wavelength: The wavelength of QSFP28 100G CWDM4 and QSFP28 100G PSM4 is around 1310 nm.

Differences of QSFP28 CWDM4 and QSFP28 PSM4 Optical Transceiver :

Connector Types: QSFP-100G-CWDM4-S optical transceiver is with LC duplex connector, while QSFP-100G-PSM4-S optics is with MTP/MPO connector.

Transmission Distance: The transmission distance of 100G QSFP CWDM4 optics is longer than that of QSFP 100G PSM4 optics. The maximum transmission distance of CWDM4 QSFP28 and PSM4 QSFP28 are respectively 2kms and 500ms.

Cost: QSFP28 CWDM4 optical transceiver module is more expensive than QSFP28 PSM4 optical transceiver module. It is on accoun that CWDM4 QSFP28 optics needs 4-wavelengths coarse wavelength division multiplexer(high in cost) while PSM4 QSFP28 optics does not need.

The Number of Optic Fiber: QSFP28 CWDM4 uses 2 single-mode fibers to transmit while QSFP28 PSM4 uses 8 single-mode fibers for transmission.

qsfp28 psm4 vs. qsfp28 cwdm4

As the components such as multiplexer/demultiplexer for the CWDM4 QSFP28 optical transceiver are very expensive, the cost of 100G QSFP28 CWDM4 optical module is much higher than that of 100G QSFP28 PSM4 optical module. It is seen from above information that QSFP28 PSM4 seemingly is more cost-effective choice than QSFP28 CWDM4. However, if the cost is taken into account from perspective of whole 100G connection, it should actually depend on the link distance. For PSM4 QSFP28 optics, as the connection distance increases, its total cost climbs up very fast due to increasing in the number of optic fibers. Therefore, 100GE PSM4 QSFP28 optics is a recommended solution with cost effectiveness for the deployment of 100G network with short reach. On the contrary, if it is to deploy 100G network with long-reach, 100GE CWDM4 QSFP28 is the better choice.

Conclusion

It is believed that the answers about what the differences between 100G QSFP28 CWDM4 and 100G QSFP28 PSM4 optical module are and which one is better are very clear. If you want to know more about them in this aspect, Gigalight official website is available for you.

About Gigalight:

Gigalight is a design innovator in global optical interconnect field. A series of optical interconnect products include: optical transceivers, passive optical components, active optical cables, GIGAC MTP/MPO cabling, cloud programmers & checkers, etc. Three applications are mainly covered: Data Center & Cloud Computing, MAN & Broadcast Video, and Mobile Network & 5G Optical Transmission. Gigalight takes advantage of its exclusive design to provide clients with one-stop optical network devices and cost-effective products.

About QSFP28 PSM4 Optics: Do You Know These?

Although there have been 200G/400G optical transceiver products appearing in the optical communication market, and it does not mean that the era of 100G optical transceiver module has come to end. Actually, there still are various 100G QSFP28 optical module in great favour, such as 100G QSFP28 PSM4 and 100G QSFP28 CWDM4 optical transceiver, which meet users’ requirements for transmission distance and costs well. Then today let’s talk about the QSFP28 PSM4 optical transceiver in this post(QSFP28 CWDM4 optics has been talked about in the last post).

What Is 100G QSFP28 PSM4 Optical Transceiver?

PSM4, the abbreviation of Parallel Single Mode 4-channels, a optics with parallel technology, defined by the 100G PSM4 MSA(Multi-Source Agreement). It uses four lanes of parallel single fiber to deliever serialized data at a rate of 25Gbps per lane. 100GE PSM4 QSFP28 will be the optical transceiver that enables single-mode fiber to become popular in next-generation data centers due to its low cost and high configurability. It doesn’t need a MUX/DEMUX for each laser but it does need a directly modulated DFB laser (DML) or an external modulator for each fiber. QSFP28 100G PSM4 uses eight fibers, in which four fibers are for transmitting and four fibers are for receiving. A PSM4 QSFP28 optical module supports link lengths of up to 500 meters over single-mode fiber with 12 fiber MTP/MPO connectors. The light source of QSFP 100G PSM4 optic module is a single uncooled distributed feedback (DFB) laser operating at 1310nm.  

Why Is 100G QSFP28 PSM4 Optical Transceiver In Demand?

It is known that the most basic 100G interfaces currently used are 100GBASE-SR4 and 100GBASE-LR4 which are defined by IEEE. However, there exists a problem between them that reaches are either too short for practical application in data center or too long and costly. In fact, for data center operators, a 100G QSFP28 optical transceiver that is with max reach of 2km or min reach of 500m is better. Thus, MSA (Multi-Source Agreement) brings a mid-reach solution to the market. And 100G QSFP28 modules with PSM4 interface are the products in this revolution. They are much less expensive than the 10km 100GBASE-LR4 modules, and support longer distance than 100GBASE-SR4 QSFP28 optical modules.

What Are the Advantages of QSFP28 PSM4 Optical Transceiver?

In addition to the common merits of QSFP28 transceiver module, such as high bandwidth, low insertion loss, high data rate and so on, the most prominent advantage of QSFP-100G-PSM4-S is shown in its cost. It is known that CWDM4 QSFP28 optical transceiver needs an optical multiplexer/de-multiplexer, operating around 1310nm with CWDM technology. After that, the amount of the components leads to the high cost of CWDM4 modules. While 100G QSFP28 PSM4 optics, unlike 100G QSFP28 CWDM4, need these components. Thus, by comparison, CWDM4 is more expensive than PSM4. As for the other types, QSFP28 100G SR4 or QSFP28 100G LR4, both are known to be high in cost.

Factors to Be Considered for the Deployment of QSFP28 PSM4 Optical Transceiver

Compared with 100GBASE-LR4, the cost of 100GE PSM4 QSFP28 optical transceiver module is much lower. But QSFP28 PSM4 needs to connect with eight parallel single-mode optic fiber for use, while 100GBASE-LR4 optical transceiver just needs 2 single-mode optic fibers. After that, if the optical fiber link is too long, QSFP 100G PSM4 optical transceiver module will have less advantages in the deployment cost. Therefore, when deploying PSM4 QSFP28, these two aspects need to be considered: parallel single-mode optic fiber has been deployed in data center; the transmission distance of optical fiber link is within 500m.

Summary

All in all, 100GE PSM4 QSFP28 optics provides a cost-effective solution for the users who demands mid-reach transmission at low cost. Above all is about the contents Gigalight wants to share with you. If you want to know more about it, welcomr to visit Gigalight official website(www.gigalight.com).

About Gigalight:

Gigalight is a design innovator in global optical interconnect field. A series of optical interconnect products include: optical transceivers, passive optical components, active optical cables, GIGAC MTP/MPO cabling, cloud programmers & checkers, etc. Three applications are mainly covered: Data Center & Cloud Computing, MAN & Broadcast Video, and Mobile Network & 5G Optical Transmission. Gigalight takes advantage of its exclusive design to provide clients with one-stop optical network devices and cost-effective products.

Essential Things You Should Know about CWDM

With the emerging of CWDM(Coarse Wavelength Division Multiplex) tech in the optical communication indusrty, various CWDM optical transciever products appear in the markets, such as CWDM SFP+, CWDM SFP, CWDM XFP, 100G QSFP28 CWDM4 and so on. Well, today, Gigalight will have an introduction to CWDM from these viewpoints that you should have a control of it.

CWDM Definition and CWDM System Principle

1. The Definition of CWDM

CWDM(Coarse Wavelength Division Multiplex), is a low-cost WDM transmission technology for MAN（Metropolitan Area Network) access layer. Speaking in principle, CWDM uses the optical multiplexer to multiplx the optical signals with different wavelengths onto the single fiber for transmission. On the receiving end of the link, the mixed signals on the optical fiber are demultiplexed into signals with different wavelengths via optical demultiplexer, and are connected to the corresponding receiving devices.

2. The Principle of CWDM System

On account that the wavelength interval of CWDM system is wide, the requirement for technology index of laser is low. Besides, due to that the wavelength interval reach 20nm, the maximum wavelength shift of the system can reach 6.5℃ to +6.5 ℃; the emission wavelength accuracy of laser can be extended to ±3nm; in the range of working temperature (－5℃～70℃), the wavelength shift caused by temperature change is still within the allowable range,the laser is not required to control the system without temperature. After that, the structure of laser is greatly simplified and the yield rate is increased.

In addition, the larger wavelength spacing means that the structure of the multiplexer/demultiplexer is greatly simplified. For example, the coating layer number of the filter in CWDM system can be reduced to about 50 layers, while that of 100GHz filter in the DWDM system is about 150 layers, which leads to higher yield rate and lower cost. The cost of CWDM filter is less over 50% of than that of DWDM filter, and will be further reduced with the increase of automatic production technology and batch size.

Advantages and Features of CWDM Tech

1. Taking Full Advantage of the Low-Loss Waveband of Optic Fiber

Making full use of the low-loss waveband of optic fiber and increasing the transmission capacity of optical fiber, the physical limit of transmitting information by one fiber can be doubled or be added by several times. Currently, a fraction of low-loss spectrum (1310nm-1550nm) of optical fiber is applied. The wavelength division multiplexing(WDM) can make full use of the huge bandwidth(25THz)of the single-mode fiber, and the transmission bandwidth is sufficient.

2. Able to Transmit Multiple Signals On the Same Optical Fiber

With the ability to transmit 2 or several non-synchronous signals on the same fiber, it is beneficial for digital signals and analog signals, independent of the data rate and modulation mode. Simulatneously, can be flexibly removed out of or added to the channels in the middle of line.

3. With High Flexibility

For the established optic fiber system, especially for early-laid optical cable with few fibers, as long as the original system is with redundant power rate, the capacity can be expanded, multiple unidirectional signals or bidirectional able to be transmitted without great changes to the original system. It is with high flexibility.

4. Quick and Convenient to Restore

Due to the reduction to application of optic fiber to a large extent, the cost is greatly decresed. Besides, because it is less in the number of optic fiber, it is quick and convenient to restore when failure appears.

5. Reducing the Cost

The shareability of active optical devices reduces the cost of transmitting multiple signals or adding new services.

6. Improving the Reliability of the System

The active equipment in the system has been greatly reduced, so that the reliability of system is improved. Currently, because multichannel carrier optical wavelength division multiplexing (WDM) has high requirements for optical transmitter and optical receiver,it is difficult to implement in tech. Simultaneously, the application of optical cables with multifibers does not bring about the critical shortage of transmission businesses of traditional broadcast TV. Therefore, the WDM is not widely applied. However, with the development of the CATV integrated services, the increasing demand for network bandwidth,the implmentation of various selective services, the consideration on cost for the network upgrade, etc, the features and advantages of WDM are gradually emerging in the CATV transmission system, showing a broad application prospect and even affecting the development pattern of the CATV network.

Applications of CWDM

1. Network Expansion and Upgrading: able to convert any input optical wavelength into fixed ITU-CWDM output optical wavelength, simultaneously to transmit up to dozen channels of optical signals, which greatly expands the transmission capacity and utilization of optical fiber, saves the time and cost of laying optical fiber cables, and starts new businesses without affecting the original businesses.

2. Hybrid Transmission of Various Signals: suitable for the upgrading of SDH, ATM, Ethernet, Fiber Channel devices, long distance line relay, analog signal transmission, and hybrid transmission of digital and analog signals in one fiber, within 10Mb/s to 2.5 Gb/s rate.

3. Mode Conversion: able to convert the single-mode optical wave into any single-mode/multi-mode optical wave, which is suitable for various complex network conditions.

4. Wavelength Conversion: able to convert any wavelength of single-mode/multi-mode optical wave into CWDM wavelength, or to convert CWDM wavelength into another arbitrary wavelength, the transmission distance able to reach several hundreds of kilometers.

5. Optical Relay: multiple CWDM can be connected in series to increase transmission distance (up to several hundred kilometers).

6. Security Networking: multiple separate virtual optical networks on the physical channels can be constituded on a pair of optical fibers, to protect the network from attacks of all software viruses and hackers. Its security is far higher than that of the general VPN, especially suitble in the fields of government, public security and banking, etc.

Conclusion

Above all is an overview of coarse wavelength division multiplex. Apart from meeting the requirements for cost saving, it is also with high reliability and flexibility, which are also key factors in the application of optical transceiver products and in the process of data transmission. For CWDM products, except for CWDM SFP+, CWDM SFP, CWDM XFP optical transceiver module, the mainly-recommended one of Gigalight is QSFP28 CWDM4 optical transceiver at present.(more details are at gigalight.com).

About Gigalight:
Gigalight is a design innovator in global optical interconnect field. A series of optical interconnect products include: optical transceivers, passive optical components, active optical cables, GIGAC MTP/MPO cabling, cloud programmers & checkers, etc. Three applications are mainly covered: Data Center & Cloud Computing, MAN & Broadcast Video, and Mobile Network & 5G Optical Transmission. Gigalight takes advantage of its exclusive design to provide clients with one-stop optical network devices and cost-effective products.