Research On All-optical Sampling Methods Based On Optical Nonlinear Effects

With the development of various new technologies,the requirements for information transmission speed are getting higher and higher.However,in current communication network,the processing of signals mainly depends on electricity.This inevitably leads to the increase of cost and the reduction of transmission rate,which cannot meet the requirements of social development.All-optical signal processing technology can transfer the signal processing to the optical domain.This process can make fuller use of bandwidth resources and solve the"electronic bottlenecks" problem in electronic technology.It will play an extremely important role in future communications.Optical fiber and semiconductor optical amplifier(SOA)are two very important optical devices,and have their own advantages.This thesis focuses on the non?linear effects in these two optical devices.Using the related theories of the four-wave mixing effect and cross-gain modulation effect,an all-optical sampling scheme based on these two devices is proposed.The main research content and achievement are summarized as follows:1.The all-optical sampling mechanism based on the four-wave mixing effect in highly nonlinear fibers(HNLF)is studied.An all-optical sampling scheme based on parametric broadcasting and dual chirped pump light is proposed.In this scheme,four-wave mixing effect is used to realize parametric broadcasting,and three replicated signals are obtained.At the same time,a linear chirp is introduced to the dual sampling pulses.The loGHz dual chirp sampling impulse is used to sample the nonreturn-to-zero on-off keying optical signal with a rate of 10Gb/s.The sampling rate of 120GSa/s is obtained.2.The mechanism of the four-wave mixing effect and cross-gain modulation in SOA is studied.Taking advantage of the small size,easy integration,and large gain bandwidth of incident light,an all-optical sampling scheme by all-optical multicast and cross-gain modulation is proposed.In this scheme,the four-wave mixing effect is used to achieve parametric broadcasting,and three replicated signals are obtained.Sinusoidal signal with a speed of 2.5Gb/s are sampled by 10GHz Gaussian light pulse,and a 120 GSa/s sampling rate is achieved.Two sampling schemes have their own advantages,which both achieve a sampling rate of 120GSa/s.The all-optical sampling scheme based on HNLF can realize a higher sampling rate with lower sampling pulses,and does not need to reduce errors through photoelectric conversion and electric-domaine qualization processing before quantization,which decreases the complexity of the all-optical sampling system.The all-optical sampling scheme based on SOA not only achieves a higher sampling rate with a lower sampling pulse rate,but also is easy to integrate.