The Research Of High Speed Spatial Optical Communication System Based On Differential Phase Shift Keying Modulation Mode

In this paper, the theoretical model and principle of DPSK(differential phase shift keying) modulation mode 10Gb/s is studied, and the parameters of the system are analyzed,and the factors affecting the signal to noise ratio and the influence degree are analyzed.First introduces the DPSK signal through the signal is loaded into the precoding Mach zed modulator converts digital signals into light phase information of the basic principle and process, and introduces the NRZ- DPSK(non zero code differential phase shift keying)mode different duty cycle other than the three principle and spectrum characteristics of each type, in the process of demodulation of DPSK system used in the interferometer theory analysis, and the demodulation process of digital simulation, may affect communication in the process of demodulation system normal work of several interference factors on the digital simulation analysis, and analyzes the working principle of balanced detector its compared to other detectors 3 dB gain advantage.In the second optical communication system, we compare the traditional Maher interferometer with a new coaxial dual core interferometer. The stability of them is analyzed,and a more stable and high precision demodulation method is provided in the DPSK high speed communication field. In addition, we analyze the influence of the optimal matching and the optimal bandwidth selection on the communication quality, which makes the whole system work under the condition of external noise.In the end of the experiment, the whole system is built based on the DPSK mode10Gb/s communication rate, and the signal wave is successfully detected from the balanced detection receiver in the premise of meeting the error rate and the sensitivity of the experiment.