基于萨尼亚克光纤干涉仪的相位调制器半波电压的测量方法

A New Method to Measure Half-Wave Voltage of Phase Modulator Based on Sagnac Optical-Fiber Interferometer

铌酸锂行波相位调制器在光纤通信和相位编码光纤量子密钥分发等领域有着广泛的应用,其半波电压参数的测量会受到一系列因素的影响而带来误差,该误差直接影响了所应用系统的整体性能。针对行波相位调制器在相位编码量子密钥分发系统中的应用模型,提出了一种基于萨尼亚克光纤干涉环的相位调制器半波电压的测量方法,由于测量装置采用了和应用模型相同的调制方式,所以测量数据具有较高的可靠性。实验针对住友公司的行波相位调制器实现了10 mV精度的半波电压测量,将之应用于差分相位编码量子密钥分发系统,得到了比采用传统的极值法测量得到的半波电压更低的误码率,为量子密钥分发系统中相位调制器半波电压的准确测量和相位电压的准确加载提供了一种有参考价值的实验方法。

LiNbO3 traveling-wave phase modulator can be used in many fields, such as optical fiber communication, phase-coding quantum key distribution system, and so on. The measurement precision of the half-wave voltage seriously affects the performance of its applied system. A new method is proposed to measure the half-wave voltage based on the Sagnac optical-fiber interferometer according to the phase modulator＇s applying model in quantum key distribution system. The data should be reliable compared with other methods because the same modulating pattern is adopted as the quantum key distribution system. This method is demonstrated experimentally with the precision of 10 mV by measuring the half-wave voltage of the phase modulator from Sumitomo corporation, which is used in the differential phase shift quantum key distribution system, and the obtained quantum bit error rate is lower than that of the conventional extreme measure method. This method can be helpful to measure the half-wave voltage of the phase modulator and the loading of phase voltage in the quantum key distribution system.