Low-kappa DBR grating filters on an InP generic photonic integration foundry platform

Abstract

We demonstrate narrow-bandwidth, low-kappa, distributed Bragg reflector (DBR) grating filters on an indium phosphide (InP) generic foundry platform. With the varying corrugation widths of the DBR grating, we achieve flexibility in the design of the coupling coefficients from 10 to 50cm−1, which correspond to grating bandwidths of 0.68 nm to 1.28 nm, respectively. These values are experimentally observed and agree well with the theoretical analysis. The DBR grating is based on periodic rectangular grooves in quaternary material that is placed between the waveguide core and cladding region. Such configurations of the DBR grating provide a low propagation loss of ∼2dB/cm near the telecom band around 1550 nm.