一种用于高精度频率传输的光纤功率补偿技术

为了抑制偏振态漂移带来的功率变化给传输稳定度造成的影响，设计了一种能够快速补偿偏振变化的频率传输系统。该系统将锁模光作为光源，结合PID控制器反馈调节的原理，利用光功率放大器(EDFA)、起偏器、可变光功率衰减器(VOA)和单片机实现。实验结果表明:该系统能够有效抑制偏振态随着环境改变而发生的漂移，经过10 km传输之后的输出光功率稳定度达到110-5，与自由漂相比提高了200倍。将整个系统应用在光梳频率传输系统中，可以提高系统的鉴相精度，在5 GHz的传输频率上，可以有效消除偏振态变化引入的~50 fs的相位抖动。

Power compensation technique for precision frequency transmission via optical fiber

In order to suppress the influence of the power variation which caused by the polarization drift brought to the stability of the transmission, a frequency transmission system which could quickly compensate the change of polarization was designed. The system which used a mode-locked laser as the light source, combining with the principles of feedback regulation of the proportional-integral-derivative (PID) control, employed the erbium-doped fiber amplifier (EDFA), polarizer, variable power optical attenuator (VOA) and single ship microcomputer. Experimental results show that the system can effectively suppress the polarization drift which changes with the environment, to make the output optical power stability reach 1×10-5 that increases 200 times when comparing with the free float after a transmission of 10 km. The design applied in the optical frequency comb transmission system, can detect the phase more accuracy, and effectively eliminate ~ 50 fs phase jitter introduced by the polarization drift on the 5 GHz transmission frequency.