Influence of SLD's power on performance of fiber optical current transformer

SLD is the only active device in the optical path of the fiber optical current transformer, and its long-term stability directly affects the performance of the transformer. This paper mainly studies the influence of SLD's power attenuation on the fixed bias, scale factor and phase of transformer's output. Research results show that the fixed offset of the transformer's output increases with the attenuation of SLD's power. Besides, power attenuation deteriorates the signal-to-noise ratio of the transformer, which leads to the increase of the ratio error and phase error. The theoretical results are verified by the experiments. Furthermore, the power attenuation has most influence on the phase error.