Optical waveguide manufactured in photo-thermo-refractive glass substrate by ion exchange

Abstract

Photo-thermo-refractive (PTR) glasses exhibit promising characteristics for volume Bragg grating fabrication, one of key devices for construction of high performance lasers, among other optical device and systems. Aiming at employing this type of glass materials in the field of integrated photonics, buried optical channel waveguide is manufactured in PTR glass substrate by Ag⁺/Na⁺ thermal ion exchange and subsequent field assisted ion migration. The Ag⁺ doped zone in glass substrate, which is also the waveguide core, can be driven to several micrometers under the glass substrate surface, which decreases the propagation loss to a value as low as 0.12dB/cm, by eliminate scattering loss at glass substrate defects. Cross section of the waveguide core can be also engineered to match the core of single mode fiber, ensures a low coupling loss to single mode fiber. Analysis demonstrated that the buried optical waveguide fabrication proves can be expected to be applied in functional integrated optical device implementation.