Indium Phosphide Photonic Integrated Circuit Testing

Here I report work done to develop an integrated amplitude and phase shaped optical frequency comb as a source for RF photonic signal processing. The first published section of work pushed towards integrated comb generation; in this work, InP devices were provided by Infinera corp., and SiN devices fabricated by professor Minghao Qi’s group. In this work a monolithic InP-based photonic integrated circuit (PIC) consisting of a widely tunable laser master oscillator feeding an array of integrated semiconductor optical amplifiers that are interferometrically combined on-chip in a single-mode waveguide is shown. We demonstrate a stable and efficient on-chip coherent beam combination and obtain up to 240 mW average power from the monolithic PIC, with 30–50 kHz Schawlow-Townes linewidths and >180 mW average power across the extended C-band. We also explored hybrid integration of the InP-based laser and amplifier array PIC with a high quality factor silicon nitride microring resonator. We observe lasing based on gain from the interferometrically combined amplifier array in an external cavity formed via feedback from the silicon nitride microresonator chip; this configuration results in narrowing of the Schawlow-Townes linewidth to 􀀀3 kHz with 37.9 mW average power at the SiN output facet. The pulse shaping was achieved using an InP ultrafast optical pulse shaper fabricated by Infinera corporation. In this work we report characterization of a 48 channel InP shaper at 50 GHz channel spacing, provisioned with both channel-by-channel phase adjusters and SOA gain elements. To our knowledge this constitutes the first demonstration of an operable integrated InP pulse shaper with independent intensity and phase control.