Optimisation of butt coupling between deep-ridge and buried ridge waveguides for the realisation of monolithically integrated wavelength selectors

Butt coupling between deep ridge and buried ridge waveguides has been optimised in terms of morphology and transition tilt angles. Low reflectivities have been found for 15 to 30 degrees tilt angles, allowing the fabrication of a four channel wavelength selector. Loss-less operation has been demonstrated for each channel.