Main Knowledge about 100G Optical Transceivers

With the development of science and technology, the application of optical communications products in real life is becoming more and more widespread. The demand for network technology is also getting higher and higher. Therefore, 100G optical transceivers are gradually appearing on the market. The development of 5G and Data Center further make the 100G optical transceivers become the mainstream of the optical transceiver market gradually. Perhaps you have had a certain understanding of 100G optical transceivers, but if we analysis 100G optical transceivers from another point of view, you will find something different.

Development Background of 100G Optical Transceivers

For the earliest developed 100G optical transceiver, the form factor is CFP, developed in 2010. At that time, IEEE launched 100G optical transceiver SR10, LR4 and ER4 three standards, separately aiming at the 100m, 10Km and 40Km transmission. Followed by that, the IEEE standard added the new 100G SR4 project, but in 2013 did not reach consensus and vacancies. By 2016, the 100G optical transceivers used by various data centers were mostly the 25Gbps Serdes program, and the 100G optical transceivers that use the 50Gbps Serdes planned slowly appeared.

The Facing Problems for 100G Optical Transceivers

1. Channel Distance: The DWDM system supporting the 50GHz wavelength distance is very extensive. The 100G optical transceiver needs to meet the condition of supporting the 50GHz wavelength distance, therefore, the pattern of high spectral power should be used.

2. OSNR (optical signal-to-noise ratio): Under the same pattern, 100G optical transceivers requires10dB higher than 10G optical transceivers and 4dB higher than 40G optical transceivers. Therefore, a low OSNR tolerance code and high coding gain FEC algorithm are needed.

3. CD Margin: Under the same conditions, 100G optical transceiver dispersion tolerance only needs 1/100 of 10G optical transceiver, accounting for 16/100 of 40G optical transceiver. Therefore, 100G optical transceivers can use dispersion compensation technology, in the electric field or the optical domain compensation to complete the dispersion compensation for each wavelength.

4. PMD Tolerance: Under the same conditions, PMD (polarization mode dispersion) tolerance of 100G optical transceiver is 1/10 of 10G optical transceivers, accounting for 4/10 of 40G optical transceiver, so you need to choose coherent reception plus digital signal processing.

5. Nonlinear Effects: Compared with 10G / 40G optical transceiver, the nonlinear effects of 100G optical transceivers are messier.

The Types and Advantages of 100G Optical Transceivers

The main form factors of 100G optical transceiver include: CFP, CFP2, CFP4 and QSFP28. To compare their advantages, the main factor to consider is the costs and power consumption for Data Centers.

1. CFP optical transceiver supports all C-band wavelengths tunable and can complete the link detection, which use a common optical dual-binary modulation format ODB, convenient layout, power consumption is less than 24W.

2. The volume of CFP2 optical transceiver is one-half of CFP, its integration is 2 times CFP. It can complete the wide dynamic input range based on SOA to achieve stable admission sensitivity, support a full CFP optical transceiver, its low power consumption is lower than 9W.

3. The volume of CFP4 optical transceiver is one-half of CFP2, its integration is twice that of CFP2, front panel port density is also doubled compared with CFP2. CFP4 optical transceiver follows the MSA protocol, support the same rate as CFP/CFP2. Its transmission power increases significantly, but the power consumption drops significantly, only about half of the original, the system cost is lower than the CFP2. In addition, CFP4 optical transceiver uses 4 * 25 forms, through the 4 * 25G channel, complete 100G transmission. The transmission power is higher with higher stability.

4. The form factor of QSFP28 optical transceiver is smaller than the CFP4 optical transceiver. QSFP28 optical transceiver power consumption is generally not more than 3.5W, the use of QSFP28 optical transceiver can directly upgrade from 25G to 100G not through 40G, and therefore the cost is lower.

Types	Standard	The Largest Transmission Distance	Connector	Channel	Wavelength	Fiber Types
CXP	SR10	100m	MPO24	12*10G	850nm	MMF
CFP/CFP2/CFP4 (CFP4 doesn’t support SR10)	SR10	100m	MPO24	10*10G	850nm	MMF
	LR4	10km	Dual LC	4*25G	1310nm	SMF
	ER4	40km	Dual LC	4*25G	1310nm	SMF
	ZR4	80km	Dual LC	4*25G	1310nm	SMF
QSFP28	SR4	100m	MPO12	4*25G	850nm	SMF
	LR4	10km	LC	4*28G	1310nm	SMF
	ER4	40km	LC	4*25G	1310nm	SMF
	ZR4	80km	LC	4*25G	1310nm	SMF
	CWDM4	2km	Dual LC	4*25G	1310nm	SMF
	PSM4	2km	MPO	4*25G	1310nm	SMF

Conclusion

Learning the contents of the 100G light module, above, do you have any further information? From the development trend, QSFP28 optical transceiver and CFP series optical transceiver are 100G network hot solutions, and the use of CXP will be less and less. Gigalight, as a veteran optical transceiver manufacturer with professional technology, advanced R & D capability and stable manufacturing capability, not only has many popular 100G optical transceiver products, like 100G QSFP28 CWDM4, 100G QSFP28 PSM4, CFP2 100G LR4, and etc. but also will release more new 100G optical transceivers in the first quarter of this year. More information about 100G optical transceivers, please visit the official website.