Study On Variable Optical Delay Line Based On Nonlinearity In Optical Fiber

All optical delay line is not only a key technology but also one of the hot issues in all optical communication network.Meanwhile,optical delay technology also has many important applications in optical coherence tomography system and microwave photonics.This dissertation focuses on the study of several variable optical delay line based on nonlinear fiber optics,which include variable optical delay line based on slow light of stimulated Brillouin scattering,self-phase modulation-based wavelength conversion and dispersion variable optical delay line and four wave mixing-based wavelength conversion and dispersion variable optical delay line.The contents are as follows: 1. The effect of slow light based on stimulated Brillouin scattering is studied.Meanwhile,the evolution of pump and signal in SBS processes has been analyzed by numerical simulation,as well as the relationship between the delay effect and pump power, fiber length and input pulse width.The threshold curves of different kinds of optical fibers are studied experimentally, and the experimental results agree well with the theoretical results. respectively. The maximum time delay of 4.36 ns is obtained in 20 km long standard single mode fiber(SSMF) based on SBS. Moreover, the maximum time delays of 2.4ns, 4.3ns and 5.7ns are obtained by using of highly nonlinear fibers(HNLFs) with lengths of 420 m,840m and 960 m, respectively. 2. Variable optical delay line of self-phase modulation-based wavelength conversion and dispersion has been analyzed by experiment simulation. The relationship between the gain and input pulse width and signal to noise ratio of two different data rate systems,10 Gbps and 40 Gbps,are studied. Variable optical delay line of two different data rate systems are studied through simulation.The maximum time delay of 10 Gbps data rate system is 653 ps and the fractional delay is 6.5. The maximum time delay of 40 Gbps data rate system is 3.92 ns and the fractional delay is 313. 3. The four wave mixing effect in optical fiber is analyzed theoretically. Simulations of factors affecting wavelength conversion efficiency, such as frequency detuning, wavelength shift, are performed. And factors affecting idler power, such as fiber length, pump power, also are performed. The wavelength conversion based on four wave mixing effect in zero-slope highly nonlinear fiber is studied experimentally.And wavelength-conversion bandwidth of 18 nm is obtained. At last, the tunable optical delay of 200ps~1100ps in 4km long standard single mode fiber is obtained, and dispersion compensation fiber of 3.88 km is 1ns~6.4ns. At last, the tunable optical delays of 200ps~1100ps and 1ns~6.4ns are obtained by using of 4km long standard single mode fiber and 3.88 km long dispersion compensation fiber, respectively.