Phase Pound – Drever-Hall Technique

Conoptics manufactures a line of laser accessories for laser modulation, driver electronics, beam deflectors, noise reduction and optical isolators. Conoptics manufactures a complete line of Electro-Optic Modulation Phase Modulation Systems designed to work specifically with Pound Drever-Hall.

Free Product Whitepapers Download Now

  • This field is for validation purposes and should be left unchanged.

The Pound-Drever-Hall (PDH) technique is an application of FM spectroscopy to detect the resonances of the optical cavity by demodulating the beam reflected from the cavity. The PDH technique is often part of a control system which regulates the frequency of a laser to match the resonance condition of a cavity. Phase modulated light, consisting of a carrier frequency and two side bands (well outside the FWHM of the cavity), is directed onto a two mirror cavity. Light reflected off the cavity is measured using a high speed photodetector, the reflected signal consists of the two unaltered side bands along with a phase shifted carrier component. This light is then measured using a photodetector and is mixed down with a phase shifted local oscillator and low pass filtered. The resulting electronic readout signal gives a measure of how far the laser carrier is off resonance with the cavity. Conoptics manufactures a complete line of Phase Modulators and Drivers to work with the PDH technique.

Phase Modulator Sensitivity


Phase Sensitivity mrad/volt @500nm

Phase Sensitivity mrad/volt @ 830nm

Phase Sensitivity mrad/volt @ 1064nm






Model 200 Driver Specifications



Rise/Fall Times

Max. Output V

Typical Drive Configuration


10KHz TO 200 MHz



AC Coupled 50 Ohms S.E.

Additional Information

Founded 1981

Over 3 Decades of Service

Customer Satisfaction

Consistently Ranked #1

Made in USA

Proudly Made in the USA

Global Representatives

19 Global Partners