The Research Of Direct Modulation Transmitting Unit In The Laser Communication System

Free space optical communication becomes a new direction of optical communication because of its advantages as broad bandwidth, high bit rate, high security and good performance on anti-jamming. The transmitting module of signal optical including such as optical generating, modulating, emitting and keeping optical wave stabilization, is very important in optical communication system.The paper subject comes from the"863"project. The main content is the research of direct modulation transmitting unit in the laser communication system. The paper analyzes the key technology of the laser direct modulation and expatiates the direct modulation theory and modulation response in the modulation process.I design the laser driving circuit and constant current source circuit according with technology target.At same time, the paper analyzes some modulation principles of free-space optical communication system, and made a performance comparison. Base on these, the thesis chooses L-PPM modulation, and designs the circuit. The paper accomplishes the design of the direct modulation transmitting unit and achieves the stated technology target.