A simple laser locking system based on a field-programmable gate array

TL;DR

This paper presents a simple, hardware-efficient digital laser locking system based on FPGA technology, offering an accessible alternative to complex analog solutions for frequency stabilization in scientific and industrial contexts.

Contribution

The authors developed a user-friendly FPGA-based laser locking system with minimal components, enabling effective frequency stabilization suitable for atom trapping and cooling applications.

Findings

Laser linewidth of 0.7 ± 0.1 MHz achieved

Locking system has a 10 ms settling time

System provides long-distance control via host computer

Abstract

Frequency stabilization of laser light is crucial in both scientific and industrial applications. Technological developments now allow analog laser stabilization systems to be replaced with digital electronics such as field-programmable gate arrays, which have recently been utilized to develop such locking systems. We have developed a frequency stabilization system based on a field-programmable gate array, with emphasis on hardware simplicity, which offers a user-friendly alternative to commercial and previous home-built solutions. Frequency modulation, lock-in detection and a proportional-integral-derivative controller are programmed on the field-programmable gate array and only minimal additional components are required to frequency stabilize a laser. The locking system is administered from a host-computer which provides comprehensive, long-distance control through a versatile interface. Various measurements were performed to characterize the system. The linewidth of the locked laser was measured to be $0.7 \pm 0.1 \; \rm{MHz}$ with a settling time of $10 \; \rm{ms}$. The system can thus fully match laser systems currently in use for atom trapping and cooling applications.