Periodically poled lithium niobate based ultra-wide bandwidth optical sampling oscilloscope

With the development of ultrahigh speed optical communications, optical sampling oscilloscope is a promising candidate for the optical performance monitoring. In this paper, a periodically poled lithium niobate based optical sampling oscilloscope is demonstrated. In the optical sampling oscilloscope, the bit rate adaptive method and chirp Z transform synchronization method are adopted to realize bit rate transparency. The optical sampling is completed by the sum frequency generation effect in periodically poled lithium niobate waveguide. The sampled signal is processed by FPGA based digital signal processing hardware, the eye diagram and parameters such as Q factor are measured. Intensity modulated optical signals with symbol rate from 1.0∼25Gbaud are measured with our optical sampling oscilloscope. The experimental results are compared with that measured with Agilent 86100A wide bandwidth optical to electronic (O/E) oscilloscope and EXFO PSO-100 optical sampling oscilloscope. The measurement results of our oscilloscope are much closer to Agilent 86100A oscilloscope. Besides, our optical sampling oscilloscope has the advantage of faster measurement speed and higher synchronization accuracy due to the novel methods we proposed. The operation stability is also measured for our optical sampling oscilloscope, and the steady state can be maintained for several hours.