It is shown that imperfect joints of linear birefringent fibres in a fibre interferometer may result in an uncontrolled visibility drift under varying environmental conditions even with a standard phase matching device. As an example, a double Mach – Zehnder interferometer is considered, which is employed in schemes of quantum key distribution. Results of numerical simulation demonstrate the standard deviation of the quantum bit error rate (QBER), which is comparable to an average QBER value.

中文翻译：

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双折射光纤接头对 Mach-Zehnder 干涉仪中能见度漂移的影响

结果表明，即使使用标准相位匹配装置，光纤干涉仪中线性双折射光纤的不完美接头也可能导致在变化的环境条件下不受控制的能见度漂移。以双马赫-曾德尔干涉仪为例，该干涉仪用于量子密钥分配方案。数值模拟结果证明了量子比特误码率 (QBER) 的标准偏差，与平均 QBER 值相当。