提出了一种新型移相光量化方案,利用光纤挤压器使光纤传输截面产生应力双折射,从而实现移相量化编码。在实验中实现了4 bit移相光量化器,用10 GHz重复频率采样脉冲对2.5 GHz正弦信号进行量化,获得量化结果的信噪比为23.9 dB,对应的有效比特位为3.68 bit。同已有的方案相比,此方案结构简单,只需要一个相位调制器,避免了多调制器工作输入信号的同步问题;利用光纤挤压器实现移相,控制精度高且成本低,可以实现高于6 bit的理论量化精度;并且可以通过光脉冲复用技术实现更高的采样速率。
In this paper,a novel phase-shifted photonic analog-to-digital conversion(PADC) scheme is presented.In order to realize the phase-shifted quantization,the phase difference between two polarizations is produced by press-induced birefringence in fiber squeezer.A 4-bit optical phase-shifted analog-to-digital system is demonstrated experimentally with 10 GS/s sampling rate,and 2.5 GHz sinusoidal electrical signal is sampled and quantized,achieving a signal-to-noise of 23.9 dB and an effective number of bits of 3.68 bits.Comparing with existing PADC methods,this scheme has a simple structure,and only needs one phase modulator,which avoids the problem of input signal synchronization;using the fiber squeezer as phase-shift module,the quantization resolution of higher than 6-bit can be achieved with high control precision and low cost;this scheme has the potential to realize higher sampling rate with optical pulses multiplex technology.