Compact Photonic Millimeter Wave (200-300 GHz) Transmitters Based On Semicircular Bow-Tie Antenna-Integrated 1.55 µm Triple Transit Region Photodiodes

Inhalt:
In this work, we present an on-chip integrated continuous wave (cw) photonic transmitter (PT) covering frequencies within 200-300 GHz in the millimeter wave (mmW) range. The compact PT (2 x 2 mm²) is realized by merging a planar broadband semicircular bow-tie antenna (SCBTA) structure (featuring hole slots) with a passive optical waveguide (POW) integrated high-speed 1.55 µm waveguide (WG) triple transit region photodiode (TTR-PD). In addition, an advanced PT concept with a monolithically integrated ridge-type semiconductor optical amplifier (SOA) WG is introduced. This is to reduce optical input power density at the PT chip facet and further to compensate optical losses in the POW. Based upon the method of moments (MoM) calculations, a peak return loss of ~27 dB and antenna directivities (even without a silicon lens) exceeding 10 dBi were obtained in the frequency range of interest. Experimentally, a tunable frequency range of 200-300 GHz, along with a 6-dB bandwidth, was achieved for fabricated SCBTA-integrated PT chips, which provide output power levels in excess of -10 dBm.