The Reasons and Impacts of High or Low Temperature on Optical Transceivers

The working temperature of optical transceivers affects all the parameters of optical transceivers. If the ambient temperature of the optical transceiver changes, the operating current of the optical transceiver will vary with temperature. At the same time, the parameters of the optical transceivers change, which affects the normal transmission of optical transceivers. Today, we mainly talk about the causes of too high or too low temperature on optical transceivers and its impact.

What Is the Normal Temperature of Optical transceivers?

Because the type and brand of the optical transceiver are complicated, the temperature of modules corresponding to different optical transceiver temperature levels are different and the temperature specifications defined by the supplier are different, whether the temperature of optical transceivers is abnormal or not needs to be considered according to these factors. Before we use the optical transceiver, it is best to check the vendor's definition of the temperature profile of the optical transceiver so as to reduce the number of problems caused by abnormal optical transceiver temperature.

Optical transceiver temperature mainly includes three levels: commercial grade, extended grade, industrial grade. The following is a detailed description of these three temperatures:

Temperature Grade	Abbreviation	Temperature Range
Commercial temperature range	COM	0 ~ + 70 ℃
Extended temperature range	EXT	-20 ~ 85 ℃
Industrial temperature range	IND	-40 ~ 85 ℃

Three Reasons That Affect the Temperature of Optical Transceivers

1. The Poor Quality and Workmanship

If you use the optical transceivers with poor quality and workmanship, then the phenomenon of abnormal temperature of the optical transceivers is more common. Because the function of such optical transceivers is instable, heat dissipation is also relatively poor. In order to reduce the temperature anomaly and unnecessary discard, we advise to use the optical transceivers with better function, quality and workmanship.

2. The Harsh Application Environment

Optical transceiver operating environment is in the data center, computer room or interchanger. If the optical transceivers are used in other environments, the change of the ambient temperature will inevitably change the temperature of the optical transceiver, thereby affecting its optical power and optical sensitivity. If the application environment of optical transceivers is harsh, then we advise to select the optical transceivers with industrial temperature or extended temperature.

3. The Use of Second-hand Optical Transceivers

The temperature of new optical transceivers is usually at 0-70 ° C and many second-hand optical transceivers are inaccessible. And the second-hand optical transceivers cannot operate normally in high-temperature or low-temperature conditions. Therefore, we advocate the use of new optical transceivers.

What Are the Impacts of High or Low Temperature on Optical transceivers?

If the optical transceiver temperature is too high or too low, it will affect the function of the optical transceiver and make the communication data appear faulty. The optical transceivers will alarm if its temperature isn’t in the normal range. If the optical transceivers are in a bad situation, interchangers will send data continuously. The optical transceivers will not send / receive data from the beginning until it is recovered to normal operation.

1. The Impact of Too High Temperature on Optical Transceivers: 

If the operating temperature of optical transceivers is too high, the optical power of optical transceivers will become larger and the receiving signal will be faulty, and even the optical transceiver will be burned. As a result, the optical transceivers cannot work normally. In this case, DDM function should be added. You can select temperature control system for real-time monitoring and compensation to ensure that the optical transceiver extinction ratio and luminous power stable, to ensure the normal operation of the optical communication system.

2. The Impact of Too Low Temperature on Optical Transceivers:

Generally speaking, as long as optical transceivers are not exposed to the harsh environment below 0℃, the temperature will not be too low. It is better not to use the optical transceiver in the condition of too low temperature, as this may cause the function of the optical transceiver to be unstable.

How about the Temperature of Gigalight’s Optical Transceivers?

As one of the most top-rated optical transceiver vendors in China, Gigalight complies with the temperature grade standard that the industry requires, and will meet the customer demand for temperature. In addition, all optical transceivers will undergo a high and low temperature burn-in test prior to shipping to test the temperature to ensure the quality of the products.

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.

5G Network Drives the Outbreak of Optical Module Market

Mobile communication is an important driving force for the development of optical networks. It is also self-evident that the development of optical modules is of great importance. We know that the optical module market can be subdivided into the Telecom market, the Datacom market and the Access market. Among them, the Telecom market is the "main battlefield" competed by the optical module industry. The biggest surprise for the future Telecom market is the evolution of 5G technology. Based on the requirement of 5G higher rate, higher capacity and higher base station density, there will be greater new demand and market space for high rate optical modules.

The Demands of Optical Transceivers for 5G Network

Although the current 5G is still in the standard stage, major equipment manufacturers have actively carried out joint trials with operators to strive to achieve 5G commercial use by 2020. "5G is commercial, carrying is the first.” It is predicted that the future number of 5G base stations will exceed 10 million, which will bring the surge in demand for optical modules in quantity. Compared with 4G technology, 5G data transmission rate is 10 to 100 times that of 4G, which means that the number of optical modules used by a single base station will increase substantially when the optical module rate remains unchanged.

We simply use a formula to represent the demand of a 5G optical module: optical module requirement (F) = base station number (m) * single base station module requirement (n). In the 5G era, compared with 4G, m and n will be significantly improved. Therefore, under the 5G construction period, the optical module will become one of the most flexible segments in the 5G industry chain. In addition, the demand for optical modules for the construction of large-scale data centers will also increase with the outbreak of 5G traffic.

To sum up, it is helpful for optical module suppliers to get ahead in the 5G era when they grasp the demand for optical modules in 5G networks in advance. So what are the specific demands of 5G optical modules? What are the mature products in the industry can initially meet the needs of 5G load? We try to analyze in the following parts.

Why Will the 100G Optical Transceivers Become the Mainstream for 5G Network?

Compared with 4G networks, 5G rebuilds the BBU into a separate architecture of CU (Centralized Unit) and DU (Distributed Unit), so its bearer needs an additional layer of intermediate network. Fronthaul - middlehaul – backhaul, the three carrier network requirements for optical modules are different. For 5G fronthaul, the CPRI bandwidth per 10MHz single-antenna port is about 614.4Mbps under ideal transmission conditions. The typical 5G wireless bandwidth is 100M ~ 1G, the peak is 20G, the antenna port may be 64 or 128. After a simple conversion, 5G fronthaul network granularity should be 25Gbps, which has been generally accepted by the industry. It can be inferred that the future 50Gbps and 100Gbps of the 5G pre-transmission modules will be the mainstream. For 5G middlehaul, it will use DWDM ring network structure, transmission distance 10 ~ 40km, n * 25G technology. This means that 100G optical modules are highly likely candidates for 5G messenger. For 5G backhaul, either with the network can be merged, but also separate. According to the future OTN networking, n * 100G technology will be adopted; if there is no OTN networking and 200G / 400G optical module technology. But no matter what kind of technology, 100G and above ultra-high-speed optical module must become the mainstream for the 5G market.

Conclusion

In conclusion, the demand of the 100G optical module by the 5G network is very urgent. At present, there are many kinds of mature 100G optical transceivers in the market, like 100G QSFP28 CWDM4, 100G QSFP28 PSM4 and 100G CFP / CFP2 / CFP4 optical modules provided by Gigalight. They cover the mainstream form factors: CFP / CFP2 / CFP4 / QSFP28 and can be used for a variety of optical network bearer demand. In particular, 100G QSFP28 and 100G CFP4 have the advantages of more compact, high module integration, transmission efficiency, power consumption and cost-effectiveness.

QSFP28 PSM4, QSFP28 SR4 and QSFP28 LR4: Which One to Choose

The appearance of QSFP28 optical transceivers is the same as that of 40G QSFP + optical transceivers. The difference is that QSFP28 optical transceiver can transmit optical signals up to 100G. Therefore, QSFP28 optical transceivers have become the mainstream of 100G optical transceivers and are the preferred solution for 100G network upgrade. There are mainly four kinds of popular QSFP28 optical transceiver modules: QSFP28 SR4, QSFP28 LR4, QSFP28 CWDM4 and QSFP28 PSM4. In this article, we will focus on describing the differences between QSFP28 PSM4 optical transceiver, QSFP28 SR4 optical transceiver, and QSFP28 LR4 optical transceiver. 

Difference between QSFP28 PSM4, QSFP28 SR4 and QSFP28 LR4

1. Different Transmission Methods

As we all know, QSFP28 optical transceivers usually have four transmission channels, and each channel data rate is 25Gbp. This transmission method is very similar with 40G QSFP+ optical transceiver transmissions. QSFP28 SR4 optical transceiver and QSFP28 PSM4 optical transceiver both use 12-way MTP interface, realizing the 8-way fiber bidirectional 100G transmission. But the QSFP28 LR4 optical transceiver cannot do this, which is transmitted at the same time in two LC duplex fibers in one direction for 100G transmission.

2. Different Transmission Media and Transmission Distance

The QSFP28 SR4 optical transceiver operates at 850nm and is used with OM3 or OM4 multimode optical fibers and OM3 optical fiber. When using together, the maximum transmission distance of up to 70m, and OM4 fiber transmission distance up to 100m.

The QSFP28 LR4 optical transceiver is usually used with single-mode fiber, which operates at 1310 nm and has a maximum transmission distance of up to 10 km.

The QSFP28 PSM4 optical transceiver is generally used with a 12-way MTP interface and single-mode optical fiber with a transmission distance of up to 2km.

3. Different Cabling Structure

Optical transceiver transmission has playing a very important role in the optical fiber routing. Because the QSFP28 SR4 optical transceiver and the QSFP28 LR4 optical transceiver are used for short-distance transmission and long-distance transmission respectively, their wiring structures are different. The former requires multi-fiber cabling based on a 12-way MMF MTP interface, while the latter requires only a traditional two-fiber SMF cabling. In this case, the conversion between multimode fiber and single-mode fiber is very complicated because they use a completely different wiring structure.

Although the QSFP28 PSM4 optical transceiver operates in single-mode fiber, its wiring structure is the same as that of the QSFP28 SR4 optical transceiver. Using the QSFP28 PSM4 optical transceiver saves conversion costs between multimode and single-mode without changing existing cabling structures.

4. Different Working Principle

(1) Working Principle of QSFP28 PSM4 optical transceiver:

The QSFP28 PSM4 optical transceiver works in much the same way as the QSFP28 SR4 optical transceiver. The difference is that the QSFP28 PSM4 optical transceiver operates on single mode fiber while the QSFP28 SR4 optical transceiver operates on OM4 multimode fiber.

(2) Working Principle of QSFP28 SR4 optical transceiver:

QSFP28 SR4 optical transceiver transmits signals at the transmitting end; the electrical signals are converted into optical signals by the laser array and then transmitted in parallel on the ribbon multimode fiber. Upon reaching the receiving termination, the photodetector array converts the parallel optical signals into parallel Electrical signals.

(3) Working Principle of QSFP28 LR4 optical transceiver:

QSFP28 LR4 optical transceivers are typically used with LC single-mode fiber optic cables to convert 4 25Gbps electrical signals into 4 LAN WDM optical signals and then multiplexed into a single channel for 100G optical transmission. At the receiving end, the module demultiplexes the 100G optical inputs into 4 LAN WDM optical signals, which are then converted into 4 electrical signal output channels.

Types	Connector	Fiber Type	Transmission Distance	Wavelength	Cabling
QSFP28 SR4	MPO	MMF	100m	850nm	12-Way MPT
QSFP28 LR4	LC	SMF	10km	1295.56/ 1300.05/1304.58/1309.14nm	Duplex LC
QSFP28 PSM4	MTP	SMF	2km	1310nm	12-Way MPT

Conclusion

The QSFP28 SR4 optical transceiver is suitable for 12-way MTP fiber cabling systems and also for short-distance transmission of OM3, OM4 multimode fiber. The QSFP28 PSM4 optical transceiver is also suitable for transmission with 12 MTP interfaces, but it is suitable for use with single-mode fibers and can transmit distances up to 500m. QSFP28 LR4 optical transceiver is for data transmission up to 2km. If you want to know more about 100G optical transceiver solution, you can visit Gigalight official website.

Main Advantages of 100G CFP4 Optical Transceivers

With the network market gradually develop from 10G to 40G and 100G, 40G/100G optical devices are also widely used in various fields. In the next few years, 100G products will continue to be popularized and gradually accepted by the market. 100G CFP series optical transceivers are available in three different package sizes: CFP, CFP2, CFP4 optical transceivers.

The 100G CFP optical transceiver is also known as 100G client module, which is a form factor pluggable module that supports hot plugging. CFP series of optical transceivers from the launch to now experienced a total of CFP, CFP2 development, and now, CFP4 optical transceiver has been successfully introduced and widely acclaimed. Compared with CFP / CFP2 optical transceiver, 100G CFP4 optical transceiver has the same rate but the transmission efficiency has greatly improved. Besides, the power consumption is reduced and the cost is lower than CFP2. CFP4 optical transceiver has irreplaceable advantages. We will talk about it in the second part.

Advantages of CFP4 Optical Transceiver:

Compared with the traditional CFP, CFP2 series, CFP4 optical transceiver has obvious advantages.

◆ Smaller size: CFP4 optical transceiver is one-half of that of CFP2, which is one quarter of CFP. It is the smallest optical transceiver in CFP series optical transceiver.

◆ Higher transmission efficiency: The early 100G CFP optical transceiver in 10 * 10 mode, through 10 10G channels, to 100G transmission rate, but the current 100G CFP4 optical transceiver with 4 * 25 mode, through 4 25G channel, to achieve 100G transmission, transmission more efficient and more stable. 

◆ Module integration is higher: CFP2 integration is 2 times CFP, CFP4 integration is four times CFP.

◆ Lower power consumption and cost: CFP4 optical transceiver is compatible with MSA protocol and supports the same speed as CFP2 and CFP2s. The transmission efficiency is obviously improved, but the power consumption drops drastically, only about half of the original, and the system cost is more than that of CFP2 low.

As we all know, 100G is the future trend of network development. With the expansion of the 100G industry, the cost of a 100G optical transceiver will also be reduced correspondingly, thereby reducing the cost of deploying the entire 100G network. Gigalight believes that CFP4 series optical transceivers for 100G applications brought will promote the 100G faster development.