Linien: A versatile, user-friendly, open-source FPGA-based tool for frequency stabilization and spectroscopy parameter optimization

• Published in: Review of scientific instruments Vol. 93; no. 6; pp. 063001 - 63006
• Main Authors: Wiegand, B., Leykauf, B., Jördens, R., Krutzik, M.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01.06.2022
• Subjects: Algorithms; Demodulation; Error analysis; Error signals; Field programmable gate arrays; Frequency stabilization; Graphical user interface; Impulse response; Locking; Machine learning; Optimization; Parameters; Power spectral density; Proportional integral derivative; Quadratures; Scientific apparatus & instruments; Software
• ISSN: 0034-6748; 1089-7623; 1527-2400; 1089-7623
• DOI: 10.1063/5.0090384

We present a user-friendly and versatile tool for laser frequency stabilization. Its main focus is spectroscopy locking, but the software is suitable for lock-in techniques in general as well as bare proportional–integral–derivative (PID) operation. Besides allowing for sinusoidal modulation (up to 50 MHz), triangular ramp scanning, in-phase and quadrature demodulation (1–5 f), infinite impulse response, and PID filtering, Linien features two different algorithms for automatic lock point selection; one of them performs time-critical tasks completely on field-programmable gate arrays. Linien is capable of autonomously optimizing spectroscopy parameters by means of machine learning and can measure the error signal’s power spectral density. The software is built in a modular way, providing both a graphical user interface as well as a Python scripting interface. It is based on the RedPitaya STEMLab platform but may be ported to different systems.