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FPGA-based Low-Latency Digital Servo for Optical Physics Experiments
Published
Author(s)
Marco Pomponio, Archita Hati, Craig Nelson
Abstract
We propose a general-purpose dual-channel field-programmable gate array (FPGA) based digital servo with a minimum latency around 200 ns. This servo implements a proportional, dual- integration and derivative (PIID) controller along with internal numerical controlled oscillators (NCO), a phase detector (PD) utilizing a fast in-phase and quadrature (I/Q) detection algorithm (80 ns), NCO modulator, network analyzer, auto-locker, ramp generator, and low pass filters. A web interface and/or python commands over TCP/IP allows full control and monitoring. The servo has been successfully used to lock Pound-Drever-Hall cavities, phase- locked loops and optical frequency combs. A simple experiment phase-locking two dielectric resonator oscillators (DRO) has been set up to demonstrate a 1 MHz closed-loop bandwidth.
Pomponio, M.
, Hati, A.
and Nelson, C.
(2020),
FPGA-based Low-Latency Digital Servo for Optical Physics Experiments, IEEE IFCS-ISAF 2020 Conference Proceedings, Keystone, CO, US, [online], https://doi.org/10.1109/IFCS-ISAF41089.2020.9234889, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=930874
(Accessed October 4, 2025)