A significant reduction of propagation losses in InGaAsP-InP buried-stripe waveguides by hydrogenation

We show here that the high propagation losses often measured at ∼1.56 μm in InGaAsP-InP buried-ridge stripe waveguides can be significantly brought down by implementing hydrogenation (exposure to deuterium plasma) as the last step to device termination. For example, losses as high as ∼30 dB/cm measured in conventional as-processed structures have dropped down after hydrogenation to typically 4-5 dB/cm. This improved loss value is totally compatible for the realization of passive sections in photonic circuits. We further present preliminary data describing the good thermal stability of these propagation losses in post-hydrogenated structures.