Bandpass filter implementations for a photonic integrated circuit

This paper describes filter designs for converting digital bandpass filters to a photonic integrated circuit (PIC). Because the filter designs must be physically realizable in an optical system, we consider a structure that not only meets the bandpass design requirements, but yields transfer function poles that avoid lasing. We consider a combination of infinite-impulse-response and finite-impulse-response stages in a multirate implementation using a cascade of optical unit cells. In order to convert the digital designs to parameter values needed in the unit cells, we describe a method for mapping the digital filter coefficients to the corresponding optical components of the PIC.