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A novel approach to interface high-Q Fabry–Pérot resonators with photonic circuits



Haotian Cheng, Naijun Jin, Zhaowei Dai, Chao Xiang, Joel Guo, Yishu Zhou, Scott Diddams, John Bowers, Owen Miller, Peter Rakich


The unique benefits of Fabry–Pérot resonators as frequency-stable reference cavities and as an efficient interface between atoms and photons make them an indispensable resource for emerging photonic technologies. To bring these performance benefits to next-generation communications, computation, and time-keeping systems, it will be necessary to develop strategies to integrate compact Fabry–Pérot resonators with photonic integrated circuits. In this paper, we demonstrate a novel reflection cancellation circuit that utilizes a numerically optimized multi-port polarization-splitting grating coupler to efficiently interface high-finesse Fabry–Pérot resonators with a silicon photonic circuit. This circuit interface produces a spatial separation of the incident and reflected waves, as required for on-chip Pound–Drever–Hall frequency locking, while also suppressing unwanted back reflections from the Fabry–Pérot resonator. Using inverse design principles, we design and fabricate a polarization-splitting grating coupler that achieves 55% coupling efficiency. This design realizes an insertion loss of 5.8 dB for the circuit interface and more than 9 dB of back reflection suppression, and we demonstrate the versatility of this system by using it to interface several reflective off-chip devices.
APL Photonics


integrated photonics, inverse design, ultra stable lasers


Cheng, H. , Jin, N. , Dai, Z. , Xiang, C. , Guo, J. , Zhou, Y. , Diddams, S. , Bowers, J. , Miller, O. and Rakich, P. (2023), A novel approach to interface high-Q Fabry–Pérot resonators with photonic circuits, APL Photonics, [online],, (Accessed June 25, 2024)


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Created November 3, 2023, Updated June 7, 2024