Abstract

A key parameter in femtosecond laser-writing of optical waveguides in glass is the rate at which the pulses are delivered to the sample. At high repetition rates (> 100 kHz), thennal diffusion and heat accumulation act in concert to produce nearly circularly symmetric waveguides in borosilicate glass, enabling low-loss coupling to optical fibers. Under similar conditions, waveguides written in pure fused silica show little evidence of heat accumulation [1], yielding properties similar to waveguides fabricated with traditional 1-kHz Ti-Sapphire lasers. In this work, we explore a broad range of exposure conditions, including two rarely studied parameters of polarization and pulse duration, to minimize propagation loss and to better understand the differing formation mechanisms in borosilicate and fused silica glass waveguides.

© 2007 IEEE