Front-end design of W-band integrated photonic transmitter with wide optical-to-electrical bandwidth for wireless-over-fiber applications

A broadband, integrated photonic transmitter front-end is demonstrated. The front-end essentially comprises a dipole-based structure fed horn antenna and a broadband slotline to coplanar-waveguide transition. The proposed dipole-based antenna feeding structure does not call for any modifications on the waveguide and bond wires on the structure for insertion loss reduction, which is critical for an easy and low-cost transmitter implementation in the milliliter-wave regime. For experimental demonstration, the proposed front-end is integrated with a near-ballistic uni-travelling-carrier photodiode (NBUTC-PD) through flip-chip bonding for realization of a W-band integrated photonic transmitter poised for high-speed wireless data transmission. Owing to wide optical-to-electrical bandwidth of the NBUTC-PD integrated with the proposed front-end, the demonstrated photonic transmitter is of a high data rate up to 12.5 Gb/s and expected to find applications in the broadband wireless-over-fiber systems.