Reconfigurable microwave photonic demultiplexer filter based on integrated coupled ring resonators for flexible and broadband satellite payloads

We demonstrate a novel 4-channel microwave photonic demultiplexer fabricated in the Si3N4 TriPleX® waveguide platform. The demultiplexer allows for a fully reconfigurable passband bandwidth (BW), ranging from 175 MHz to 1 GHz, and central frequency tunability spanning in the whole Ka-band. Each channel is based on a high selectivity Coupled Ring Optical Waveguide (CROW) filter with 8 ring resonators, where the round trip length per ring is equal to 7.94 cm (free spectral range of 2.48 GHz). Reconfigurability is achieved by using power efficient (<1 μW) stress-optic lead zirconate titanate (PZT) - based actuators. The experimental evaluation of the filter shows fiber-chip-fiber insertion loss < 5 dB and a flattop passband with power ripple <1dB. The 20 dB /1dB BW steepness is given by a shape factor of 1.8, while the stopband suppression is equal to 55 dB. The group delay variation at the passband is < 2.3 ns.