Polarization Independent Optical Isolator in Sagnac-Type Configuration

TL;DR

This paper introduces a polarization-independent optical isolator using Faraday rotators and half-wave plates in a Sagnac configuration, achieving high isolation levels regardless of input polarization.

Contribution

It presents a novel design for a polarization-independent optical isolator that does not rely on walk-off effects, demonstrated through an experimental prototype.

Findings

Achieved isolation levels between 43 dB and 50 dB for all input polarizations.

Successfully tested the device's performance with various polarization states.

Demonstrated the feasibility of polarization-independent isolation in a Sagnac-type setup.

Abstract

We propose a polarization-independent optical isolator that does not use walk-off between the two orthogonal polarizations. The design is based on two Faraday rotators in combination with two half-wave plates in a closed, Sagnac-interferometer-like, configuration. An experimental prototype is tested successfully under variation of the input light polarization state with isolation level between 43 dB and 50 dB for all input polarizations (linear, circular, or elliptical).