Optical Nonlinearity:Phenomena, applications, and materials

We present a theoretical overview of soliton switching phenomena in two-mode nonlinear couplers. By complementing numerical studies with perturbative or exact solitary wave solutions, one finds that nonlinear Schrodinger or sine-Gordon solitons tend to maintain their identity in the coupled systems. Moreover, the coupling itself may originate novel vector solitary waves, such as gap solitons in periodic media. The switching dynamics in the presence of dissipative perturbations such as linear gain or intrapulse Raman scattering is also discussed.

Soliton switching in nonlinear couplers

All optical logic gates based on an asymmetric nonlinear directional coupler

We propose and analyze a passively mode-locked laser based on an active nonlinear directional coupler. Implementation of this concept in a dual-core erbium-doped fiber laser should result in stable trains of sub-100-fs pulses.

Passive mode locking through nonlinear coupling in a dual-core fiber laser.

We give an approximate analytical solution to the coupled nonlinear Schrodinger equations that govern the soliton switching in a nonlinear fiber coupler. We have derived, in simple analytical form, the switching condition by which solitons can be switched from one core to another. The analytical result has been checked against the numerical results, and it is found that there is close agreement.

Analytical solution to soliton switching in nonlinear twin-core fibers

A numerical study of the all-optical switching properties of solitons in an erbium-doped nonlinear fiber coupler is presented. The small gain provided by the erbium both lowers and sharpens the switching threshold, while producing pulse-compression factors of 3 to 9. As a result, we show that it is possible to achieve all-optical switching, amplification, and compression of short pulses in a single device.

Soliton switching in an erbium-doped nonlinear fiber coupler.

Algebraic coupled level set-volume of fluid method for surface tension dominant two-phase flows

A numerical study of the all-optical switching properties of an active nonlinear directional coupler is presented. The switching power is reduced for both CW and soliton inputs because of the gain. The switching properties of the coupler are enhanced for solitons, which switch nearly completely. For ultrashort pulses, the effects of the bandwidth of the gain medium are considered by using a general form for the gain band. The gain spectrum of erbium is also considered as a specific example.

James Wilson

Papers

Soliton switching in an erbium-doped nonlinear fiber coupler.

Algebraic coupled level set-volume of fluid method for surface tension dominant two-phase flows

All-optical switching of solitons in an active nonlinear directional coupler

Finite volume Ghost Fluid Method implementation of interfacial forces in PISO loop

Phase-change mechanism for evaporation in porous media using volume of fluid: Implicit formulation of interfacial temperature