Research On Wavelength Calibration System For Diode Laser

Laser interferometry is widely used in the field of precision measurement for its high measurement accuracy and wide range.Diode lasers are favored in laser interferometry systems due to their small size and low price.Since the laser wavelength is easy to be influenced by the environment and drive current,which leads to the decrease of the precision of interferometry,real-time monitoring and calibration of diode laser wavelength is extraordinary important for precision measurement.In this paper,a wavelength calibration system for diode laser is developed to monitor the laser wavelength in real time,which can eliminate or minimize the error caused by wavelength drift.The main work of the thesis is as follows:1.A laser wavelength calibration principle based on Michelson interference is proposed.This principle adopts a Michelson interferometer with fixed optical path difference.Laser enters and then interferes in the system.The wavelength variation can be obtained from the interference phase change,through which we can achieve the wavelength calibration.2.The hardware architecture design of the calibration system is completed,including the optical structure and photoelectric signal processing circuit.Based on ARM,the circuit system can realize signal acquisition,interference phase analysis,wavelength variation measurement and data transmission.3.The calibration system is integrated into the displacement measuring instrument based on laser interferometer.The drift of the laser wavelength is monitored and calibrated in real time,and then the result of the displacement measuring instrument can be calibrated.The experiment of laser wavelength calibration system is carried out to verify the validity and accuracy of the system.