Soliton and quasi-soliton switching in nonlinear optical loop mirror constructed from dispersion decreasing fiber

The performance of a standard nonlinear optical loop mirror (NOLM) device a nd the NOLM constructed with a dispersion decreasing fiber (DDF) operating in the soliton and quasi-soliton regime is investigated numerically. Result s showed that the soliton regime present best behavior when compared with t he quasi-soliton regime. One concludes that operating the NOLM in the solit on regime, the first, second and third transmission maxim could be obtained with low pump power compared with the quasi-soliton regime. It was also ob served that in the basic NOLM device, the output pulse duration is very dep endent on length of the fiber. In the quasi-soliton regime, the transmitted pulse present strong shaping effects (compression). However, in the solito n regime, the transmitted pulses present fewer fluctuations in the time dur ation with pump power. The output pulse duration present more stability wit h a bigger time duration (C = 0.6), Our simulations considering four differ ent profiles, linear, hyperbolic, exponential and Gaussian conclude that, o n average, the hyperbolic profile gives the lowest pump power for the first , second and third transmission peaks of transmission compared with the oth er profiles. The Gaussian profile presents the worse behavior. It was also observed that with a proper choice of the dispersion profile we could have a transmitted pulse with no distortion in the soliton regime. For the quasi -soliton regime, strong compression was observed. (C) 1999 Elsevier Science B.V. All rights reserved.