Optical chips are micro devices that use the principles of photonics to achieve mutual conversion between optical signals and electrical signals. It is the core component of optical communication technology and is widely used in the construction of optical networks such as routers, base stations, transmission systems, and access networks.
Optical communication chips generate optical signals through light sources, transmit optical signals using waveguides, and convert optical signals back into electrical signals through detectors, thereby realizing the transmission and processing of information. The working principle of optical communication chips is based on the principles of photonics.
The main process includes three stages: emission, optical transmission, and optical detection: 1. Light emission: The light source (such as a laser or LED) converts the electrical signal into an optical signal. This process is usually achieved by semiconductor materials emitting light through transitions between energy bands, such as by doping specific elements on a silicon substrate to form a quantum order structure. 2. Light transmission: The optical signal is transmitted through a waveguide structure. The design of the waveguide enables optical signals to be efficiently transmitted inside the chip while avoiding scattering and loss of optical signals. The optical signal between waveguides may interfere, and this phenomenon is used in optical chips to achieve signal modulation and amplification.
3. Light detection: The detector chip converts the received optical signal back into an electrical signal. This process is achieved through the photoelectric effect, that is, under light, the electrons in the material absorb the energy of the photon. If the absorbed energy exceeds the work function of the material, the electron will escape the material to form a photoelectron and generate a positively charged hole. The detector chip usually uses a phototransistor to complete this conversion process.
Types of optical communication chips:
Optical communication chips are the core components of optical communication technology. According to different functions, structures and application scenarios, optical communication chips can be divided into many types.
1. Laser chip
Mainly used to transmit signals and convert electrical signals into optical signals.
① Edge-emitting laser chips: including FP (Fabry-Perot) lasers, DFB (distributed feedback) lasers and EML (electroabsorption modulated lasers). FP lasers are mainly used for low-speed short-distance transmission; DFB lasers use grating filter devices to achieve single longitudinal mode output based on FP lasers, and are mainly used for high-speed medium and long-distance transmission; EML combines the advantages of DML (direct modulation laser) and DFB lasers, and improves output power, transmission rate and temperature stability by integrating electro-absorption modulators
②Surface emitting laser chips: such as VCSEL (vertical cavity surface emitting laser) chips, which are characterized by the light output direction being perpendicular to the chip surface, low threshold current, high modulation rate and good single-mode characteristics, and are suitable for short-distance optical communication and optical sensing and other fields
2. Detector chip
A chip used to receive optical signals and can convert optical signals into electrical signals
①PIN detector: PIN detectors have high sensitivity and low dark current, and are suitable for medium and short-distance optical communication transmission
②APD (avalanche photodiode) detectors: APD detectors add avalanche multiplication effect to PIN detectors, thereby improving sensitivity, but also require higher operating voltages. APD detectors are suitable for long-distance, high-speed optical communication transmission
Application of optical communication chips:
As the core component of optoelectronic devices, optical communication chips have a wide range of applications, covering communications, industry, consumer electronics, automobiles and other fields
1. Communications: Optical communication chips are widely used in optical fiber access, 4G/5G mobile communication networks, data centers and other communication fields. In these application scenarios, optical chips are mainly used for optical transmission components and optical receiving components of optical modules, and are the core components of modern optical communication systems
2. Industrial field: Optical chips also have important applications in industrial automation, intelligent manufacturing and other aspects. For example, high-power laser chips can be used for industrial processing and manufacturing, while low-power laser chips are used for precision measurement and detection
3. Consumer electronics: Optical chips are widely used in smart phones, wearable devices, virtual reality (VR), augmented reality (AR) and other fields. For example, VCSEL (vertical cavity surface emitting laser) used for mobile phone face recognition and 3D sensing technology
4. Automotive field: Optical chips have important applications in vehicle-mounted laser radar, autonomous driving, intelligent networked vehicles and other aspects. These applications use optical chips for environmental perception and obstacle detection to improve the safety and intelligence level of vehicles
5. Medical field: Optical chips are widely used in medical diagnosis, medical imaging, etc. Photonic chips can be used in technologies such as fluorescence imaging and optical coherence tomography (OCT) to improve the accuracy and efficiency of diagnosis
6. Artificial intelligence computing: Optical chips are widely used in high-performance computing and artificial intelligence. Photonic chips can be used to accelerate the training and reasoning of large-scale neural networks, significantly improving computing efficiency
7. Quantum communication: Optical chips also have important applications in the field of quantum communication. Using the quantum properties of photons for information transmission, it has high security and anti-interference capabilities
In the future, optical communication chips will continue to develop in the direction of higher speed, lower power consumption, and smaller size. The continuous advancement of silicon-based optoelectronic technology will promote the deep integration of optical communication chips and CMOS processes, realize the monolithic integration of optoelectronic devices and electronic devices, further reduce costs, and improve integration and reliability
