Semiconductor Lasers And Photodetectors, The Equivalent Circuit Model

Optoelectronic integrated circuits (OEIC) has become the key technology of optical fiber communications, and establish an accurate, simple circuit model of optoelectronic devices is the important start of OEIC. Semiconductor lasers and light detectors as the core devices of optical fiber communication system,the research on their equivalent circuit model is particularly important.The working principle of semiconductor lasers and optical detectors, and their basic structures have been discussed based on the physical basis. According to the semiconductor laser rate equations, an equivalent circuit model including electrical circuits, optical circuits and phase loop, has been established. Similarly, the equivalent circuit model of semiconductor optical detector has been established, based on the rate equations of PIN photodiode active region. Using circuit simulation software PSpice, the equivalent circuit models have been simulated, and the models can correctly reflect the input and output characteristics, frequency response and pulse modulation response of the real device.Submount is an important part in testing and packaging of the laser chip, the electrode structure on it has an important effect on the high-frequency characteristics of the laser. Parasitic parameters are determined by the electrode size and the gap between them. Designing match electrode structure with the chip can improve the frequency response of the device. The electrode structure on the submount of the laser chip has been simulated and analyzed by HFSS. First, the general electrode structure has been simulated, then a new electrode structure has been simulated and compared, and it has been optimized in size and gap of the electrode.