UC Santa Barbara

Self-referenced optical combs have proven pivotal for numerous metrology applications including precision navigation, LiDAR, and molecular spectroscopy. While plenty of research has improved and broadened the scope of this instrument, most implementations to date have been lab-scale setups that require kilowatts of power. The size, weight and power (SWaP) needs to shrink in order to fully realize the potential of this technology.

Silicon chip-based Photonic Integrated Circuits (PICs) provide a platform to exploit the same optical phenomena in a reduced SWaP. However, these miniature devices are inherently prone to fabrication variation and environmental fluctuations during operation. An associated issue is the coupling of precision and power. Where bench top implementations can circumvent many issues by increasing the laser power to mitigate downstream losses in optical elements, an integrated solution requires novel electronic signal estimation, detection and stabilization architectures to maintain precision under a low power budget.

This dissertation presents a mixed-signal controller designed to handle the challenges of achieving parts-per-trillion frequency stability in an integrated optoelectronic frequency synthesizer. I discuss the development of a heterodyne-based architecture and highlight experimental results from a PCB prototype using commercial-off-the-shelf electronics. The limitations present at the board-level are further mitigated by the development of a custom IC. Results from an application-specific integrated circuit (ASIC) designed in 55nm CMOS show the potential of integration in reducing the SWaP. Ultimately, this architecture achieves state-of-the-art performance, producing a 193 THz output with 5.6 mHz average deviation (2.9e-17 ADEV @ 1000s). The synthesizer is tunable >40 nm across the C-band with 745 mHz setpoint resolution, capable of full configurability in real-time via a custom Graphical User Interface (GUI).