光纤时间传输及相位补偿

Time-Frequency Transfer via Optic Fiber and Phase Compensation

介绍了国外几种利用光纤进行时间频率传递的方法和经验。对无补偿光纤时间频率传递方法、双向时间频率传递方法、光学机械温度补偿方法及电子共轭相位补偿方法作了较详细的描述。光纤时延主要随温度而变化,在200km以内,时延的日变化为几纳秒,月变化为十几纳秒。在50km内利用光纤传输100MHz频率信号时,在不补偿情况下频率稳定度为:3×10-14/s,1×10-15/d;光学补偿后的频率稳定度可达到1.5×10-14/s,1×10-17/d。电子共轭相位补偿后,温度变化20℃引起的相位变化降低了45倍。光纤传输对短期频率稳定度影响较小,对日及更长期的频率稳定度影响较大。

Some methods and experiences on time-frequency transfer via optic fiber are introduced. The methods for time-frequency transfer without phase compensation, two-way time-frequency transfer, temperature compensation via optic-mechanics and electronic conjugated phase compensation are described in detail. The time delay in optic fiber transfer changes mainly with temperature. Within a distance of 200 km, the changes of time delay are a few nanoseconds for one day and ten-odd nanoseconds for one month. If a 100 MHz signal is transferred via optical fiber within 50 km, the frequency stabilities are 3 ×10^14/S and 1 ×10^15/d for the case without compensation, and the frequency stabilities are 1.5 ×10^14/s and 1 ×10^17/d for the case with optical compensation. The electronic conjugated phase compensation can reduced the phase variations, which is caused by temperature change of 20℃, by a factor of 45. The effect of optic fiber transmission on the short term stability is smaller than that on the long term （day and longer than day） stability for time-frequency signal.