What Is SFP?

SFP stands for Small Form-Factor Pluggable. It is a compact, hot-pluggable transceiver used for both telecom and datacom applications.

SFP module has two ports, one port has laser inside, which is the transmitter side. The other port has a photodetector inside, which is the receiver side. So basically, SFP is a transceiver module, since it has transmitter and receiver in a single unit.

Which Components Make Up the SFP Optical Module?

The SFP optical module is composed of laser, circuit board IC and external accessories. The external accessories include shell, unlocking part, buckle, base, gripper, rubber plug, PCBA, and the color of gripper can help you to identify the parameter type of the module. For the types of SFP module, there are many types for SFP module such as BIDI-SFP, Electrical interface SFP, CWDM SFP, DWDM SFP, SFP+ transceivers and so on. In addition, for the same type of XFP, X2, XENPAK optical transceivers, SFP optical transceivers can not only be directly connected with it, but also have the feature of lower cost than it.

How Are the SFP modules used on the PCB board?

The following picture shows a perspective view of the SFP module, so you can clearly see its mechanical outlines.

SFP

Gigalight 10G SFP+

SFP module’s mechanical interface and electrical interface are specified by a multi-source agreement, also called MSA.

MSA is an industrial group composed of many network component vendors, such as Finisar, Fujikura, Lucent, Molex, Tyco, etc.

Engineers from these major vendors came together and made a design that everybody agreed upon. So based on this MSA specification agreement, these companies can make products that can work together in a system without compatibility issues. It is almost like an industry standard.

SFP was designed based on the bigger GBIC interface, but SFP has a much smaller footprint in order to increase port density. That is why SFP is also called mini-GBIC.

SFP modules are classified based on the working wavelength and its distance reach. Let’s take a look at the list here.

For multimode fibers, the SFP module is called SX. SX modules use 850nm wavelength. The distance that the SX module supports depends on the network speed. For 1.25 Gbps, the reach is 550 meters. For 4.25 Gbps, SX modules support 150 meters.

For single mode fibers, there are a lot of choices. I am listing the most common types here.

LX modules use 1310nm wavelength laser and support up to 10km reach. ZX modules use 1550nm wavelength laser, and supports reach up to 80km. ZX modules also use 1550nm laser but support up to 120km reach.

There are also CWDM and DWDM SFP modules, which use multiple wavelengths in the module to support even more bandwidth and distance.

And don’t forget, the MSA also defined a SFP module based on the UTP twisted pair copper cables. But this SFP module currently only supports Gigabit Ethernet.

Traditional SFP modules support the speed up to 4.25 Gbps. But an enhanced version, which is called SFP+, supports up to 10Gbps, and is becoming more popular on 10Gigabit Ethernet and 8Gbit Fibre Channel.

SFP transceivers are used on all types of network applications, including telecommunication, data communication, Storage Area Network.

On the protocol side, there are SFP modules that support SONET/SDH, Gigabit Ethernet, Fibre Channel, Optical Supervisory Channel, and more.

Conclusion

Gigalight is committing to providing cost-effective products for customers. 10G optical modules such as 10G SFP+, 10G CWDM SFP+, 10G DWDM SFP+ can be provided by Gigalight. Gigalight has been investing in the development of colored (CWDM/DWDM) transceivers which have been widely sold around the world. You can find more relevant information from Gigalight‘s official website.

5G Is Driving the Evolution of Optical Transceiver Industry

We are now starting to see commercial 5G networks going live. Previous generations were focused on consumer and personal communications but now 5G will serve consumers, enterprises and take the internet of things to the next level, where superior connectivity is a prerequisite. Initially, 5G will be a capacity enhancer in metropolitan areas and enhanced mobile broadband and fixed wireless access will be ways for operators to address explosive traffic growth.

According to LightCounting, 5G will drive significant growth in the global market for optical transceivers since 2019, especially in China. At the same time, the demand for low-speed optical devices below 10G will gradually decrease and increase in the demand for transceivers of 25G, 50G, and 100G.

The change of optical transceiver demand is driven by 5G revolution. RAN architecture of the 5G system will realize the separation of CU and DU, which determines that 5G wireless network will include fronthaul, midhaul and backhaul. New requirements are proposed in terms of the amount of optical transceiver and the technical requirements of the optical transceiver.

Optical transceivers Need to Be Able to Meet the Requirements for Bearer Network in 5G Era

Fronthaul

The transmission distance should be within 10km or even shorter. The operating temperature should reach industrial temperature and the CPRI interface rate should reach 25Gbps.

Midhaul

The transmission distance should be at least 10km and the operating temperature should reach the commercial temperature. Gray optical transceiver or BiDi is mainly considered. In addition, 50G PAM4 may be a good choice.

Backhaul

The transmission distance should be more than 10km and the operating temperature should reach the commercial temperature. The 100G, 200G, 400G rate optical transceiver is mainly used. In addition, WDM or coherence technology will be taken into consideration.

Since the evolution of CPRI interface to PRI will lead to an increase of RRU power consumption, more heat-resistant optical transceivers are needed. In addition, the wireless architecture will evolve from DRAN to CRAN, and there will be a shortage of optical cable resources, which requires more energy-saving optical transceivers. In addition, 5G will use a higher frequency band, the coverage will be smaller, and the number of optical transceivers will be greatly increased so that the low-cost optical transceivers are needed. At the same time, 5G’s spectrum bandwidth increases transmission bandwidth, and higher speed optical transceivers are needed to meet this demand.

Conclusion

All in all, the core requirements for optical devices in wireless scenarios are mainly reflected in higher operating temperature range, less fiber resource consumption, lower cost, and faster single wave rate.

How to meet these needs of optical transceivers in the 5G era?

The solutions for High-temperature transceiver — industrial temperature light chip and silicon light can make the optical device itself work at high temperature, and can guarantee rapid heat conduction through good thermal design.

The solutions for optical fiber resource shortage—the most obvious solution is to use BiDi, which can save 50% of the optical fiber resources and thus use the existing optical fiber resources to transmit twice the bandwidth. Passive WDM solutions are also available.

Building on the success of the company’s 10G CWDM SFP+

transceiver and 10G DWDM SFP+ transceiver, Gigalight developed its next-generation 25G CWDM in an SFP28 form factor. And Gigalight 25G SFP28 BiDi optical transceivers are available. This technology is believed to be a key building block for deploying these transceivers and is designed to enable cost-effective next-generation 5G wireless build-outs while also providing significantly more data capacity per fiber than other 25Gbased optical architectures. This will enable Transceiver-to-transceiver communications and self-wavelength tuning of remote transceivers during commissioning without host interaction, so field installation and remote maintenance are simplified and operational expenses are lowered.

According to different scenarios, there are different requirements for optical transceivers. The traditional optical device technology in the field can meet the current needs, but there is a trend to update the technical field of evolution. At the same time, the realization path of the growth of optical transceiver rate also presents a diversification trend. Finally, no matter what you need are, Gigalight is here to create, assist and innovate.

Wavelength-tunable Optical Transceivers

What Is Wavelength-tunable Optical Transceiver?

Tunable optical transceivers are similar in operation and appearance to fixed transceivers, however, they have the added capability of allowing you to set the channel (or color) of the emitting laser. This reduces the need to have multiple devices that each operates at fixed wavelengths installed within a network. Instead, you have one transceiver that can be tuned according to the requirements of the operator.

Tunable transceivers are only available in DWDM form, because of the format of the dense wavelength grid. Typical tunable optics are designed for the C-Band 50GHz. They support approximately 88 channels which are set with a 0.4nm interval. They usually start from channel 16 and go up to 61, but this is dependent on the manufacturer of the router or switch and which channels it supports.

Tunable optical transceivers for DWDM systems have been widely available within the telecommunications industry for many years.

There are two main types of tunable transceivers such as XFP and SFP+.

XFP Tunable

Tunable XFP transceivers are designed with an integrated full C-Band tunable transmitter and high-performance receiver. This means that wavelengths can be set as default in the 50GHz DWDM grid. With single mode fiber, XFP tunable transceivers can operate at distances up to 80km.

Depending on the manufacturer, the names for these products can vary even though they have the same operational features.

These optics can be tuned in different ways. Most devices make it possible to tune over the CLI (Command Line Interface), but not every switch or router is capable of this.

SFP+ Tunable

Tunable SFP+ transceivers are full duplex, serial optical devices. The transmit and receive functions are contained within a single module which provides a high-speed serial link at 9.95 to 11.3Gbps signaling rates.

Again, these products can operate at distances of up to 80km with single mode fiber.

What Are the Benefits of Tunable Transceivers?

As technology has progressed, tunable transceivers have improved drastically. They are now very popular within DWDM transmission systems because of their capabilities and ease of use.

The key benefits are:

Wide tuning range

Suitable for 100G systems because of reduced line-width

The convenience of wavelength adjustment depending on transmitting needs

Reprogramming takes seconds

Saves money in the long term

Conclusion

Tunable optical transceivers are able to operate at various wavelengths and adjust their wavelength according to each users’ needs. They are very popular in DWDM systems due to cost-saving factors and flexibility of use.

At Carritech, we stock and support a full range of optical transceiver products. To view our stock, learn more about our products or inquire about purchasing visit our optical transceiver page.

Gigalight can provide 10G tunable SFP+ and 10G tunable XFP optical transceivers. The 10G tunable SFP+ is with low power consumption, lower than 1.7W. The wavelength of this module is stable and the transmit optical power is about 0dBm. The extinction ratio is greater than 10dBm; the side die suppression ratio is greater than 51dB, the eye-diagram crossing point is between 47% and 52 %, and the sensitivity of this module can reach above -24dBm. It supports distance up to 80km. And the 10G tunable XFP can be piled into two versions to support FEC coding function (OTN G.709 framing) and non-FEC coding function. The power consumption of the former is less than 4.5W, and the advantage of the FEC coding function is to improve the sensitivity of transmission; while the power consumption of the latter without FEC function is less than 3.5W. The two versions are available to meet maximum distance of 80km as well as to be compatible with the switches and core routers of Cisco, Juniper, and other major equipment suppliers.