All-UV-written integrated planar Bragg gratings and channel waveguides through single-step direct grating writing

A single-step technique is presented, for defining two-dimensional integrated channel waveguide structures with internal Bragg gratings in photosensitive germanosilica-on-silicon substrates using two interfering focused UV beams. Detailed device analysis of the relationship between the photosensitive properties of the glass, UV writing conditions, and subsequent refractive index change and channel waveguide strength is presented, based on grating characterisation. Through software control, 300 nm-wide grating detuning across the E, S, C, L, and U wavelength bands is demonstrated.