Silicon photonic microresonator-based high-resolution line-by-line pulse shaping
Lucas M. Cohen, Kaiyi Wu, Karthik V. Myilswamy, Saleha Fatema, Navin B. Lingaraju, Andrew M. Weiner
Abstract
Optical pulse shaping stands as a formidable technique in ultrafast optics, radio-frequency photonics, and quantum communications. While existing systems rely on bulk optics or integrated platforms with planar waveguide sections for spatial dispersion, they face limitations in achieving finer (few- or sub-GHz) spectrum control. These methods either demand considerable space or suffer from pronounced phase errors and optical losses when assembled to achieve fine resolution. Addressing these challenges, we present a foundry-fabricated six-channel silicon photonic shaper using microresonator filter banks with inline phase control and high spectral resolution. Leveraging existing comb-based spectroscopic techniques, we devise a system to mitigate thermal crosstalk and enable the versatile use of our on-chip shaper. Our results demonstrate the shaper’s ability to phase-compensate six comb lines at tunable channel spacings of 3, 4, and 5 GHz. Specifically, at a 3 GHz channel spacing, we showcase the generation of arbitrary waveforms in the time domain. This scalable design and control scheme holds promise in meeting future demands for high-precision spectral shaping capabilities. High-resolution pulse shaping is highly sought after, but existing systems are impractical outside of laboratory settings. Here, the authors introduce a chip-scale spectral shaper that uses high-Q microresonator filter banks and inline phase control to manipulate lines at GHz-level spacing.