Photonic chips use light waves (electromagnetic waves) as carriers for information transmission or data calculation. With the development of the optoelectronic semiconductor industry, optoelectronic devices (optical chips), as core components in the upstream of the industrial chain, have been widely used in communications, industry, consumption and other fields.
What is an optical chip?
Photonic chips use light waves (electromagnetic waves) as carriers for information transmission or data calculation. Electronic integrated chips use current signals as information carriers, while photonic chips use higher frequency light waves as information carriers. Compared with electronic integrated circuits or electrical interconnection technologies, photonic integrated circuits and optical interconnections exhibit lower transmission loss, wider transmission bandwidth, smaller time delay, and stronger ability to resist electromagnetic interference.
Optical chips include CCD, CIS, LED, photon detectors, optocouplers, laser chips and many other types. If classified according to whether photoelectric signal conversion occurs, optical chips can be divided into active optical chips and passive optical chips. Active optical chips include transmitting chips and receiving chips, and passive optical chips include optical switch chips and optical beam splitters. chips etc. The following mainly analyzes the active optical chip, such as laser chip and photon detection chip industry development.
Active optical chips, especially laser chips, are mainly used in industry (high-power laser chips) and communications (high-speed laser chips). In addition, VCSEL and silicon photonic chips are in the growth stage, and there will be broader development space in the future.
In the field of optical communication, the optical chip is the core component of the optical module’s transmitting and receiving components, which respectively realize the conversion of electrical signals to optical signals and optical signals to electrical signals, and determine the transmission rate of optical modules.
In industrial applications, optical chips, heat sinks, beam shaping devices, etc. constitute the pump source of fiber lasers and solid-state lasers, providing energy for the working medium in the laser to achieve particle number inversion.
In consumer applications, optical chips have been widely used in 3D sensing (mobile phones, cars) and other scenarios. Taking automotive lidar as an example, optical chips are the core components of the transmitter and receiver, which determine the detection distance and resolution of the lidar. rate and other key performance.
Compared with large-scale integrated circuits that have formed a high degree of industrial chain division of labor, the optical chip industry has not yet formed a mature PCB design-foundry- IC packaging and PCBA testing industry chain. Internationally leading optical chip manufacturers, such as II-IV, Lumentum, etc., mostly use the IDM model.
The main reason for this is that optical chips are mainly manufactured using special processes, and the threshold for chip manufacturing technology is relatively high, and the production line is difficult to achieve standardization. Manufacturers adopt the IDM model to achieve collaborative optimization of the production process and meet the diverse needs of customers.
China’s optical chip development status
At present, China’s high power laser chips and some high speed laser chips (10G, 25G, etc.) are in the stage of accelerating the breakthrough of localization, while optical detection chips and high speed laser chips above 25G have just started, and localization still has a long way to go.
In terms of manufacturers, Chinese local optical chip companies mainly focus on high-power applications such as industry/defense, which is also their main source of revenue. Therefore, in terms of high-power laser chips, local Chinese companies are able to compete with international giants such as II-VI and Lumentum.
However, in the field of optical communication and consumer applications, there is a big gap with international manufacturers, which is the focus of the next step. The optical communication market has a vast space. At the same time, optical chip manufacturing processes such as optical communication and VCSEL are highly reusable with high-power laser chip processes. Local Chinese companies can enter based on their own technology accumulation.
High power laser chip
The industrialization of high-power laser chips in the United States and Europe started earlier, and they have leading advantages in technology. Traditional giants include II-VI, Lumentum, ams Osram, IPG, etc. In recent years, China’s domestic laser chip technology has continued to make breakthroughs, and related industries are in a period of rapid development. Major manufacturers include Everbright, Huaguang Optoelectronics, DoGain Laser , and Raybow Laser.
The product power of Chinese local companies has been improving. Take Everbright as an example. The company was established in 2012. At the beginning of its establishment, it developed a high-brightness single-tube chip above 13W. In 2019, it launched a 15W single-tube chip. Single-tube chips will achieve mass production of 30W single-tube chips in 2021. At present, its products are continuously iterating to higher power levels.
According to relevant statistics , the localization rate of China’s 25G optical chips is about 20%, and the localization rate of more than 25G is only about 5%. In recent years, local Chinese enterprises have made breakthroughs in the 25GDFB laser chip for 5G base station pretransmission optical module, and optical module enterprises for data centers began to use the domestic 25GDFB laser chip.
Optical detection chip
Optical detection chips are widely used in application scenarios such as mobile phones, optical communications, and smart home appliances (such as sweeping robots). With the rapid development of the automotive lidar industry, optical detection chips, as the core components of the lidar receiving end, are expected to usher in new development opportunity.
In terms of technical solutions, at present, APD is the mainstream solution, and First-sensor, Hamamatsu and Kyosemi are the top three manufacturers in the industry, with the market share of the three reaching 45%. The more advanced technical solution than APD is SPAD/SiPM. Compared with APD, SPAD/SiPM has stronger detection sensitivity. At the same time, SiPM is in the form of an array, which is easier to match with the array light source and easier to integrate with the CMOS process, thereby reducing costs .
Therefore, SPAD/SiPM is expected to become the future development direction of lidar receiver chips. However, SPAD/SiPM technology is difficult and the entry threshold is high. The global SiPM market is mainly dominated by leading companies such as ON Semiconductor, Hamamatsu, and Broadcom, with a total market share of 83%.
Currently, Chinese companies have a low international market share in optical detection chips.
According to the “China Optoelectronic Device Industry Technology Development Roadmap (2018-2022)” released by the China Electronic Components Industry Association, the development of optical chips such as SPAD in China is highly dependent on production technology and packaging testing. ON Semiconductor, which is the main supplier in the SPAD field , the main suppliers of CIS/CCD are international manufacturers such as Canon and Sony, which have the experience and capability of large-scale packaging and testing.
On the one hand, it relies heavily on foundries in the United States, Singapore, Germany and other countries, coupled with the scarcity of technical personnel familiar with related processes, resulting in slow development of key technologies, long chip development cycles, and low efficiency.
However, China’s domestic market and related companies also have their own advantages. Compared with international manufacturers , Chinese optical detection chip manufacturers have better flexibility in product customization and price advantages. In the future, with the development of products, Continuous breakthroughs in technology.
At present, Chinese local companies have a clear choice for the optical detection chip solution. Companies represented by Accelink,and Sanan Optoelectronics choose traditional and mature PIN-PD and APD solutions, and their products are mostly used in optical communications, while the entrepreneurial companies represented by Adaps Photonics choose SPAD/SiPM solutions whose layout represents the future development direction.
Moreover, Chinese SPAD/SiPM products have begun to be used in consumer electronics, lidar, AR/VR, medical and other fields. In addition, there are cases where Chinese local companies lead the world in terms of single product strength. For example, the single photon detection efficiency (PDE) of Adaps Photonics products at a wavelength of 905nm reaches 25%, exceeding the industry average (5%~18%) ).
VCSELs
With the continuous improvement of key performances such as VCSEL power density, it is expected to become the core component of the semi-solid/solid-state laser radar transmitter.
Compared with light sources such as LEDs and EELs, VCSEL lasers have many advantages, such as low mass production costs, high wavelength stability (small temperature drift), easy two-dimensional integration, low threshold current, high-frequency modulation, and no cavity surface threshold damage wait.
Relevant reports show that since Apple introduced the 3D sensing function in iPhoneX in 2017, VCSEL has developed rapidly in the field of consumer electronics applications, and the main application has gradually shifted from high-speed data communication of 850nm devices to 3D sensing applications of 940nm devices.
At present, international giants Lumentum and II-IV dominate the VCSEL chip market by virtue of their technological advantages. According to statistics, the combined market share of Lumentum and II-IV in 2021 will exceed 80%.
China’s VCSEL chip companies for sensing applications mainly include Everbright, Vertilite, Ningbo Ruixi, Lemon Photon, RAYSEES, etc. Most of them are entrepreneurial companies. Advantages, is trying to catch up with the pace of international advanced technology and product development, and through a variety of ways to enhance their own competitiveness, for example, using the IDM model to build core competitiveness.
Silicon optical chip
Silicon photonics chips are photonic integrated chips developed based on silicon wafers. They have unique advantages in size, speed, and power consumptionand can be widely used in optical communication, data center, medical detection, automatic driving, national defense and other fields. Among them, Optical communication is the most important application market for silicon photonics chips.
Silicon photonics chips have the characteristics of high integration and low cost, and have broad development prospects in the context of photonic integration.
At present, the world’s leadingmanufacturers and suppliers in silicon photonics technology and industrialization mainly include Intel, Cisco, and Inphi. In recent years, well-known companies such as Cisco, Huawei, Ciena, and Juniper have deployed silicon photonics technology through acquisitions. Marvell, Cisco, Nokia and others have spent tens of billions of dollars to acquire Inphi, Acacia, Elenion and other silicon optical innovation companies.
Both Intel and TSMC are vigorously developing silicon photonics manufacturing process technology, and have formed a relatively complete silicon photonics chip industry chain.
Conclusion
