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

We present a single-step technique for defining 2-dimensional integrated channel waveguide structures with internal Bragg gratings in photosensitive germanosilica-on-silicon substrates using two interfering focussed 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, 300nm wide grating detuning across the E, S, C, L, and U wavelength bands is demonstrated.