Pulse compression and pedestal suppression by self-similar propagation in nonlinear optical loop mirror

摘要

We propose and investigate a unique nonlinear pulse compression mechanism which provides low-pedestal, few-cycle ultrashort pulses at 800 nm. In order to accomplish this aim, we propose a fiber compressor based on self similar design and nonlinear optical loop mirror (NOLM) configuration. The proposed NOLM consists of chloroform infiltrated polarization maintaining tapered photonic crystal fiber (TPCF) which has been designed on the basis of self-similar technique. The coupler of the NOLM plays a key role in the suppression of pedestal and formation of high-quality compressed pulses. The dynamics of higher-order chirped solitons in a designed pulse compressor has been simulated numerically, to rigorously incorporate self-switching characteristics of NOLM and the self-similar property of the fiber. For a 140-fs input pulse with 100 W, quality analysis at the output of NOLM reveals a compressed pulse with a FWHM of 6.98 fs, compression factor of 20.05, and pedestal energy of 2.5% in a 4.9 cm long fiber.