High contrast all-optical spectrally distributed switching of femtosecond pulses in soft glass dual-core optical fiber

TL;DR

This paper demonstrates high-contrast all-optical switching of femtosecond pulses in a specially designed dual-core soft glass fiber, achieving significant contrast with very low control pulse energy, advancing optical switching technology.

Contribution

It introduces a novel all-optical switching method based on nonlinear dual-core asymmetry control in a high-index contrast soft glass fiber, with optimized fiber length for best performance.

Findings

Switching contrast exceeds 20 dB with nanojoule control pulses

Optimal fiber length identified as 14 mm, matching theoretical coupling length

Significant improvement over previous soliton-based dual-core fiber switching methods

Abstract

All-optical switching of 77 fs pulses centered at 1560 nm, driven by 270 fs, 1030 nm pulses in a dual-core optical fiber exhibiting high index contrast is presented. The fiber is made of a thermally matched pair of lead silicate and borosilicate glasses used as core and cladding material, respectively. The novel switching approach is based on nonlinear balancing of dual-core asymmetry, by control pulse intensity induced group velocity reduction of the fast fiber channel. Due to the fiber core made of soft glass with high nonlinearity high switching contrast exceeding 20 dB is attained under application of control pulses of only few nanojoule energy. The optimization of the fiber length brought the best results at 14 mm, which is in good correspondence with the calculated coupling length at the signal wavelength. The results express significant progress in comparison to similar studies based on self-switching of solitonic pulses in dual-core fibers and represent high application potential.