A many-channel FPGA control system for laser stabilization and other applications

Open Access
- Author:
- Schussheim, Daniel
- Graduate Program:
- Physics
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 12, 2023
- Committee Members:
- Mikael Rechtsman, Major Field Member
Venkatraman Gopalan, Outside Unit & Field Member
David Weiss, Major Field Member
Mauricio Terrones, Program Head/Chair
Kurt Gibble, Chair & Dissertation Advisor - Keywords:
- Field-programmable gate array
laser
atomic physics - Abstract:
- We present a many-channel digital feedback control system based on a field programmable gate array (FPGA). We use the FPGA to implement digital signal processing features including fast infinite-impulse response filters, lock-in detection and modulation, arbitrary waveform generation, and a touchscreen for experimental control. The FPGA connects to a custom baseboard with 10 channels of 100 mega-sample per second (MS/s) 16-bit analog-to-digital converter fast inputs, 14 channels of 100 MS/s 16-bit digital-to-analog converter fast outputs, 16 channels each of 16-bit slow inputs and outputs at 125 kS/s and 50 kS/s, and dozens of digital inputs and outputs. This control system can support up to 10 servos updating at 100 MS/s, and potentially dozens of slow servos with analog inputs and digital or analog outputs. An initial experimental application was tested at Penn State where this system was used to control the laser system to laser-cool and trap cadmium atoms. In chapter 1, we provide an introduction with background and motivation on control systems and the cadmium laser system. We then discuss the hardware in chapter 2, and the FPGA software and firmware in chapter 3. Chapter 4 discusses three experimental applications: a fast laser lock with a dither lock correction, pulse width modulation temperature servos, and arbitrary waveform generation. Chapter 5 provides a summary and suggests future directions for modifying and improving the control system.