| Superluminescent diode (SLD) is used as the light source of interferometric fiber optic gyroscope (IFOG) currently. The stability of SLD has vital effect on performance of FOG. Kinds of control method of SLD have been analyzed in this paper, and a precisely digital control system of SLD has been designed. This system can be used to test the optical output power of SLD automatically.Firstly, the principle and characteristic of SLD have been analyzed. The effect of SLD's stability on IFOG and the theory of thermoelectric cooler (TEC) have also been discussed in this paper.Based on the analysis of the analog control method commonly used now, a digital control system is proposed using method of "constant current and temperature control" and the advanced PID controller with integral separated is designed.The result of a great deal of experiment shows that the digital control method proposed in this paper is better than the analog one widely used at present. The stability of optical output power and spectrum including temperature stability and long time stability is advanced in great degree. The stability of optical output power tested by the function of system designed in this paper is similar to the one tested by a digital optical power meter. So this digital control system of SLD can be used to test the stability of optical output power of SLD. |
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