Faster and faster speed and lower energy consumption are the common goals of all communication equipment R&D and production today. With the development and maturity of technical means, optical fiber communication technology has developed relatively mature and has become the most popular research direction in the field of communication today. As an important node responsible for photoelectric conversion in the field of optical communication, the technology and application of optical modules have become a hot spot.
5G network development status
5G (5th generation mobile networks) is the fifth generation of mobile communication technology. The core idea of its technology is to realize the information interaction between people and things based on the traditional information interaction between people, so as to realize the “Internet of Things”. MBB (Enhance Mobile Broadband), mMTC (enhanced Machine Type Communication) and URLLC (Ultra Reliable & Low Latency Communication) are one of the international standardization organizations. The three major scenarios of 5G defined by the Third Generation Partnership Project (3GPP). In general, 5G has the following characteristics.
- High speed
Compared with the traditional mega-speed, 5G technology brings double the speed improvement, and the peak speed of 5G base station is as high as 20Gb/s. Under such a high-speed network, the user experience will be greatly improved, and new services with high-speed requirements such as VR and unmanned driving derived from this will also more easily enter people’s lives.
- Low latency
According to the application requirements of industrial automation and unmanned driving, even a delay of tens of milliseconds may cause serious consequences. , in some cases enough to threaten the safety of passengers. Under 5G technology, the delay of network services can often reach less than 1 millisecond, or even lower, which is also one of the major advantages of the future development of 5G technology.
- Internet of Things
In the past, communication terminals were still immobile, such as radio stations and fixed telephones. With the development of mobile communication, the number of terminals has increased exponentially, and each person has one or even multiple mobile phones, but in the 5G era, this number will explode. This is because by that time, terminals will no longer only represent laptops and mobile phones, but everything used in life may be connected to the network and become a member of the communication family.
The goal of 5G communication is to support at least 100W mobile terminals per square kilometer. At that time, our refrigerators, TVs, etc. can be intelligentized and become smart furniture, and people’s lives will also undergo earth-shaking changes. Scenes that previously existed only in science fiction will appear around each of us.
Development trend of optical modules
Optical communication is the core technology of contemporary information networks, and optical modules play a vital role in the entire information network because of its photoelectric conversion function.
The optical module industry chain includes electrical/optical chips, passive and active devices, and finished modules. Among them, chip technology occupies the highest value in the entire industry chain, accounting for about 30~70%, and most high-end chip products are developed by foreign countries.
Enterprise monopoly; in terms of optoelectronic devices, there are many categories, the amount of active value is relatively concentrated, and the global professional collaborative competition; the iteration speed of optical module products is significantly accelerated, the development of high-speed optical module research and development and market applications continue to develop, and the growth rate of the entire market space is rapid. .
At present, the related technologies of low-speed optical module products have gradually matured. At present and in the future, 100G optical modules and 400G optical modules will become the mainstream of the market.
There are currently two mainstream solutions for 400G optical modules, namely OSFP (25G PAM4*8) and QSFP-DD (50G NRZ*8). Because of its low power consumption and high integration, silicon photonics is expected to significantly reduce costs during large-scale commercial production. Compared with traditional optical devices, silicon optical devices theoretically have the following advantages.
- Low cost: The cost of silicon-based materials is low, and the investment, facilities and processes of CMOS in the field of integrated circuits can be used to greatly improve the manufacturing process level of optical devices and further reduce costs;
- Low power consumption: low impedance of silicon-based materials, low device driving voltage, and reduced energy consumption;
- High degree of integration: Silicon-based materials and technologies can provide a unified manufacturing platform for photonics and electronics, provide a way for chip-level optoelectronic integration, and further reduce the cost and size of system equipment.
According to the packaging form, optical modules can be divided into GBIC, SFP, XFP, QSFP, CFP, etc. The GBIC module has a hot-swappable electrical interface, which can support the long-distance transmission of single-mode fiber and optical signals at the level of 100 kilometers.
SFP is a compact, pluggable transceiver module standard used in telecom and datacom applications. SFPs provide functionality similar to GBIC modules, but at half the size of GBICs.
XFP is a small form-factor pluggable transceiver module standard at 10G rates that supports multiple communication protocols such as 10G Ethernet, 10G Fibre Channel, and SONETOC-192. XFP transceivers can be used in the datacom and telecom markets and offer better power consumption characteristics than other 10Gbps transceivers.
QSFP28 is a compact, pluggable transceiver standard primarily used in high-speed data communication applications. At present, QSFP28 is widely used in global data centers.
CFP is based on a standardized dense wavelength division optical communication module, and the transmission rate can reach 40-100Gbps. The size of the CFP module is larger than that of SFP/XFP/QSFP optical modules, and it is generally used for long-distance transmission such as metropolitan area networks.
In recent years, with the gradual maturity of market demand and R&D technology, the speed of optical modules has become faster and faster, and the version interval has become smaller and smaller. The transmit and receive wavelengths of optical modules used in single-wavelength communication systems generally have three transmission windows: 850nm, 1310nm, and 1550nm, of which 850nm is suitable for short-distance multimode transmission, 1310nm is suitable for medium-distance transmission, and 1550nm is suitable for long-distance transmission. Compared with single-wavelength communication systems, wavelength division multiplexing (WDM) technology can multiply the network bandwidth, so it is widely used.