Applicable ultrafast all-optical switching by soliton self-trapping in high index contrast dual-core fiber

Improvement potential of ultrafast all-optical switching by soliton self-trapping using all-solid dual-core fibers with high index contrast was analyzed numerically. Study of the femtosecond nonlinear propagation was performed based on the coupled generalized nonlinear Schrödinger equations considering three different fiber architectures: homogeneous cladding all-solid, photonic crystal air-glass and photonic crystal all-solid. The structure geometries of the all three alternatives were optimized in order to support high-contrast switching performance in C-band considering 100 fs level pulse widths. Comparing the three different structural alternatives, the lowest switching energies at common excitation parameters (1700 nm and 70 fs pulses) were predicted for the homogeneous cladding dual-core structure. The further optimization of the excitation wavelength and pulse width resulted in lower switching energies at simultaneous improvement of the switching contrasts at combination of 1500 nm,75 fs pulses and at 43 mm fiber length. The spectral aspect in this optimized case expresses broadband and uniform switching character spanning over 200 nm and exceeding 30 dB contrast at more frequency channels.