Design of ultra-compact multimode interference (MMI) couplers and high efficiency grating couplers in TriPleX platform as part of a photonic based sensor

We present simulation and characterization results for the design of a two-port grating coupler with achievable coupling efficiency up to 54% together with simulation and characterization results of three different multimode interference (MMI) coupler structures, 1x2, 1x4 and 1x8 with insertion loss and output power imbalance as low as 0.2 dB and 0.05 dB, respectively. Both grating coupler and MMI photonic structures were designed on the TriPleX platform. Finally, we present these structures as part of a novel, photonic, ultrasensitive biosensor.