Nonvolatile polarization control of a bistable VCSEL

Mathias Marconi,Massimo Giudici,Stéphane Barland

doi:10.1364/oe.20.00b299

Abstract

We report experimental evidence of nonvolatile all-optical memory operation using the two linear polarization states emitted from a GaAs oxide-confined VCSEL. The two polarization states coexist in a large range of pumping currents and substrate temperatures, and they can be controlled all-optically by exposing the device to polarization selective feedback, to crossed polarization reinjection orby injecting external light pulses. The active polarization state is recovered after powering off and on the VCSEL, while memory is lost if the substrate temperature is varied.

Highlights

Since the discovery of bistability in optical resonators, optical devices have been proposed as units for processing information [1]
We report experimental evidence of nonvolatile all-optical memory operation using the two linear polarization states emitted from a GaAs oxide-confined Vertical-Cavity Surface-Emitting Lasers (VCSELs)
The active polarization state is recovered after powering off and on the VCSEL, while memory is lost if the substrate temperature is varied

Summary

Introduction

Since the discovery of bistability in optical resonators, optical devices have been proposed as units for processing information [1]. In Vertical-Cavity Surface-Emitting Lasers (VCSELs) bistability may be obtained by taking advantage of the polarization degree of freedom. Because of their symmetric structure,VCSELs do not exhibit anisotropies strong enough to fix the polarization direction. A very different situation has been observed by Kawaguchi, reporting bistability between two orthogonal LP states in a large current interval [7]. This bistability is not disclosed by hysteresis in the L/I curve and it can be revealed only by injecting polarized light pulses into the VCSEL for inducing polarization switching. This surprising behavior discloses a modification of the VCSEL parameters which is not reset by powering the device off and it may have applications as non-volatile optical bit memory

Experimental set-up

Polarization bistability of the VCSEL output

Control of the polarization emission

Nonvolatile optical memory

Discussion and conclusions