Bragg fiber design for linear polarization

Abstract

A new design is presented for Bragg fibers that allows low-loss propagation for linearly polarized light. Predictions based on a simple ray model show that approximately doubling the thickness of the first wall layer results in low losses at TM-like boundaries while keeping TE-like boundary losses manageable. This contrasts sharply with conventional quarter-wave designs that are extremely low loss for TE01 modes but very high loss for linear polarization. We fabricate Bragg fibers based on this design concept in a Si/SiO2 system and verify experimentally that they propagate linearly polarized light with losses less than 6 dB/cm over a 60-nm spectral range.