The Semiconductor Laser Equivalent Circuit Model Simulation And Parameter Extraction

As the light source in optical fiber communication systems, semiconductor laser with high-speed direct modulation characteristics of optical fiber communication is one of the key components. Optical fiber communication transmission characteristics depend on the merits of laser working characteristics, so using a variety of researching methods to laser performance is becoming increasingly important. In this paper, equivalent circuit method is used to study the factors that affect the laser working characteristics, and provided with a theoretical basis for the optimal design and improving the performance of the laser.Firstly, the equivalent circuit models of laser research status at home and abroad are elaborated. Energy levels and energy transition theory are used to describe the principle of laser emission, various parts of the structure and roles of laser components are outlined. On this basis, equivalent circuit model are derived from the laser rate equations, which is constituted by the circuit model, optical circuit, phase circuit and the package parasitic circuit. Then the modeling and implementation process of various laser parts in simulation software are discussed.Secondly, basic operation characteristics of laser are simulated, including P-I characteristic, V-I characteristic, small-signal frequency response, impulse response, and frequency chirp characteristic. The effects of gain compression factor to the relaxation oscillation characteristics of laser are studied.Finally, the effects of DC bias, working temperature, modulation amplitude and other external factors to laser output power, bandwidth, frequency chirp are studied. And we obtain the conclusion that appropriate DC bias, operating temperature, modulation amplitude should be chosen to make laser to achieve the best working conditions. The effects of package parasitic parameters to laser frequency response are discussed, Laser combination parameter extraction method is extracted from the measured P-I characteristics data and small-signal frequency response data with detailed formulas.