Research On Optical Receiver Module Of Double Polarization Modulation Laser Ranging System

Laser ranging technology,which features the characteristics of non-contact,high directivity and high precision,has been the main method of length measurement in application fields.Second polarization modulation laser ranging system,comparing with the traditional laser ranging techniques,has higher application value because of its high accuracy,small size,low cost and so on.The optical receiver module,as the core component of laser ranging system,determines the ranging accuracy to a great extent.Therefore,this thesis focuses on the question of how to design optical receiver module that could optimize the ranging accuracy.Firstly,the mathematical model of second polarization modulation laser ranging system has been established and its measurement principle has also been analyzed.Then,came the introduction of the basic principle of the design of optical receiver circuit,it includes gain,bandwidth and stability design of photoelectrical converter circuit,basic structure and the selection of A/D converter,circuit noise calculation,and methods of controlling the noise of A/D converter circuit.After the introduction of relevant basic theories,based on the measurement accuracy index of1×10^-6,according to the basic measurement principle,the thesis calculated that when the modulation frequency was 1GHz,the dynamic range of frequency scanning curve equals to 0.8 times of the full scale input range,the noise-free code resolution?NFCR?of optical receiver circuit was required to achieve13.15bits.According to the basic design idea of the optical receiving circuit,an optical receiver module with 11.1 bits NFCR was designed and achieved.In addition,the implementation of other important components of the laser ranging system was accomplished,including microwave source,controller,other optical devices and ranging system software programming.At the end of the thesis,the laser ranging system was tested.First,the conversion precision of DC signal of the optical receiver module was 8.72 bits.After increasing the number of average times,the conversion accuracy has been effectively improved.Then the bandwidth of passive filter design was verified.Chebyshev?passive low pass filter with bandwidth of 1.33MHz was realized.Finally,the ranging accuracy of laser ranging system was verified.After receiving many times of the optical data and calculating the average,the system design goal could be achieved,with the range accuracy achieved1.04×10^-6.