In Gaussian-modulated coherent-state quantum key distribution,the measurement of quadratures of coherent states is performed by using a homodyne detector.However,conventional detectors usually suffer from narrow bands...In Gaussian-modulated coherent-state quantum key distribution,the measurement of quadratures of coherent states is performed by using a homodyne detector.However,conventional detectors usually suffer from narrow bands.We present a method to design a high-speed shot-noise-limited balanced homodyne detector.A 300-MHz bandwidth detector is experimentally tested and the level of shot noise is 14 dB higher than the electronic noise.The results show that a detector with this method is potential to design a GHz bandwidth detector for continuous variable quantum key distribution at a low level of ratio of shot noise to electronic noise.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 61170228China Postdoctoral Science Foundation under Grant No 2013M540365.
文摘In Gaussian-modulated coherent-state quantum key distribution,the measurement of quadratures of coherent states is performed by using a homodyne detector.However,conventional detectors usually suffer from narrow bands.We present a method to design a high-speed shot-noise-limited balanced homodyne detector.A 300-MHz bandwidth detector is experimentally tested and the level of shot noise is 14 dB higher than the electronic noise.The results show that a detector with this method is potential to design a GHz bandwidth detector for continuous variable quantum key distribution at a low level of ratio of shot noise to electronic noise.
