Hybrid integrated Si3N4/InP photonic integrated circuits for dynamic optical arbitrary waveform generation

Abstract

Optical arbitrary waveform generation (OAWG) is capable of working in the ‘line by line’ regime to control arbitrary amplitude and phase over individual lines of an optical frequency comb (OFC). To accomplish this, the OAWG waveform shaper separates the optical comb lines from the OFC using a spectral demultiplexer, applies modulation to each line with an array of modulators, and combines the modulated comb lines using a spectral multiplexer. User-defined complex spectral shapes and arbitrary temporal waveforms can be synthesized on demand, thereby facilitating applications like microwave arbitrary waveform generation, agile microwave-photonic filtering, and coherent communications, etc‥ The main limitation of current integrated solutions has been high optical insertion loss and a large degree of crosstalk between channels. Instead of attempting a monolithic technology platform, we implement low loss and high contrast Si 3 N 4 arrayed waveguide gratings (AWGs) as spectral de/multiplexer, and InP phase modulator array for nearly pure phase modulation. We heterogeneously integrate Si 3 N 4 and InP chips by active alignment and UV epoxy assembly, and demonstrate dynamic OAWG in a single integrated chipset.