The Research On Light Source Drive Circuit For FOG

With the rapid development of optical communication,semiconductor optical device technology has also been further improved.Fiber optic gyro(FOG)technology is becoming more mature in the field of inertial technology.It has gradually developed into a mainstream instrument widely used in the military and civilian fields.Light source as the only active optical device in FOG.Control and drive of light source is one of the key technologies in the field of FOG.Super luminescent diode(SLD)having a desired spectral width index.It has a large output power and has a good coupling effect with FOG.It is widely used in medium and low precision in the FOG.FOG source gain characteristic is non-linear.In order to ensure the stability of the optical wavelength and output optical power,the injection current of the die must be controlled to be constant.Due to environmental factors,the stability of the SLD has a great impact on the accuracy of the system.SLD light emission wavelength,the spectral width of the optical power and stability of the affected environmental temperature surrounding the die significantly.The driving current of the light source is also affected by temperature.Thus,this paper the influence SLD die injection current and temperature change of the system design FOG light source driving circuit and the accuracy of the test.First,through research and analysis of the large number of documents,focusing on the basic principles of FOG light source and the light source assembly.Because FOG is based on the Sagnac effect of light,the reliability and stability of the light source is the basis of FOG work.By analyzing the light emission mechanism and light emission characteristics of different FOG light sources,it is revealed that the main factors affecting the light source performance are the working temperature of the die and the stability of the injected current.While the configuration and operation principle of a light source assembly units a lot of research.the research provides for low-power,high-precision design of the light source driving circuit and ways.Secondly,it analyzes the design principle of low power,high precision light source driving circuit.Detailed study of the sources of error of each functional unit and the corresponding reduction approach,designed to complete the light source drive control circuit FOG.And the performance index of the circuit is tested under different conditions.The test results show that the designed light source drive control circuit is optimized to optimize the device and drive and control circuit design to better solve the problems of reducing power consumption and reducing volume.In FOG ensure high-precision control light(optical output power stability is better than 3‰ constant temperature,the temperature control accuracy of 0.01?)conditions,of low power and constant current source circuit miniaturization goal.The circuit meets the performance requirements for the engineering,miniaturization,mass production,and development of high-precision FOG and three-axis combined FOG for medium and low-precision FOG.Finally,using circuit integration technology,a feasible integration scheme was designed for the driving circuit of the fiber optic gyro light source.It meets the low power circuit,miniaturization and high-precision requirements.According to the circuit's requirements for integrated technology,a technical solution is adopted that integrates the light source module,the control circuit integration module,and the power amplification and parameter adjustment module.After cooling and immunity of the circuit influence system performance analysis,completion light source driving circuit board design using Altium Designer and the instrument finished prototype design of the light source drive control.After testing,the low power consumption and high precision light source driving circuit can ensure the stable output optical power and the SLD light source die work normally under the continuous change of the ambient temperature(-40?60?).Temperature control accuracy of light source within 3 seconds is better than 0.01?,and constant current accuracy better than 0.1%.It enables the system to achieve performance with high accuracy and high stability.