Frequency Detection And Working Point Control System Of Y-shaped Cavity Orthogonal Polarization Laser

Y-shaped cavity orthogonal polarization laser is a kind of dual-frequency lasersource with large dynamic range and high frequency stability, not only can be used asthe source of a dual-frequency laser interferometer, but also can become a sensordirectly, has great significance and application value in the precision measurement field.The laser’s normal work and processing of the measure result need the guarantee ofrelated circuit. This paper is focused on the research of the frequency detection andworking point control system of Y-shaped cavity orthogonal polarization laser. Themain work of this paper is as follows:In this paper, firstly, the working principle and orthogonal polarization modecharacteristic of Y cavity orthogonal polarization laser are introduced. Thus it’s pointedout that the development of frequency detection and working point control system is anessential work in the research of Y-shaped cavity laser and gas sylphon acceleration;And then the principle and performance requirements of the frequency detection andworking point control system, besides the range and accuracy of frequencymeasurement, are analyzed.Secondly, the method of pre-assigned frequency combined with pulse subdivisioncounting for frequency measurement of GHz magnitude signal is put forward; and thenthe hardware and software of the frequency detection circuit is designed, and themeasuring error of the circuit is analyzed, theoretically.Then according to the output characteristics of Y-shaped cavity orthogonalpolarization laser, the design of working point control circuit through the polarizedlight-intensity differential is put forward; then the hardware and software of the circus isrealized based on the FPGA circuit. And working point control circuit and frequencydetection circuit are integrated into a complete auxiliary circuit system of Y-shapedcavity laser.Finally, the experimental tests on the frequency detection and working pointcontrol system of Y-shaped cavity orthogonal polarization laser are performed. Usingthe medium and low frequency signal from an arbitrary waveform generator and thehigh frequency beat signal from Y-shaped cavity orthogonal polarization laser, themeasurement range and accuracy of frequency detection circuit is tested, and the errorcurve is given; and then the working point control experiment on Y-shaped cavityorthogonal polarization laser is performed, and the curve of light-intensity differentialis given. The experiments shows: that the frequency detection and working point controlsystem of Y-shaped cavity orthogonal polarization laser works properly; themeasurement range and accuracy of frequency detection circuit meet beat frequencysignal measurement requirements of Y-shaped cavity orthogonal polarization laser; the response time of the working point control circuit is less than1s, the control accuracyof light-intensity differential is less than the3.37x10-2mV.