An all optical phase shifter and switch near 1550nm using tungsten disulfide (WS2) deposited tapered fiber

TL;DR

This paper demonstrates an all-optical fiber phase shifter and switch near 1550 nm using tungsten disulfide (WS2), leveraging thermo-optic effects in a tapered fiber for applications in optical signal processing.

Contribution

It introduces a novel fiber-based all-optical phase shifter and switch utilizing WS2, showing effective phase modulation and switching capabilities with low cost and compact design.

Findings

Maximum phase shift of 6.1π near 1550 nm

Extinction ratio of 15 dB for the switch

Rise time of 7.3 ms for switching

Abstract

Optical phase shifters and switches play an important role for various optical applications including optical signal processing, sensing and communication. In this paper, we demonstrate a fiber all optical phase shifter using few-layer 2D material tungsten disulfide (WS2) deposited on a tapered fiber. WS2 absorbs injected 980 nm pump (control light) and generates heat which changes the refractive index of the tapered fiber due to thermo-optic effect and achieves a maximum phase shift of 6.1{\pi} near 1550 nm. The device has a loss of 3.7 dB. By constructing a Mach-Zehnder interferometer with WS2 based phase shifter in one arm, an all optical switch is also obtained with an extinction ratio of 15 dB and a rise time of 7.3 ms. This all fiber low-cost and compact optical phase shifter and switch demonstrates the potential of 2D transition metal dichalcogenides for all optical signal processing devices.