Skip to Main Content
Your organization might have access to this article on the publisher's site. To check, click on this link:http://dx.doi.org/+10.1063/1.1142031
A new servo circuit based on the thermal phase‐locked loop (TPLL) has been developed for frequency stabilization of internal‐mirror He‐Ne laser. A feedback signal proportional to the fluctuation in the frequency of the laser is down‐converted through a voltage‐controlled oscillator (VCO) and compared in a phase/frequency circuit with that of a frequency reference. The detected phase difference then drives a heater wrapped around the laser tube for tuning the laser cavity length. The frequency stability achieved is ±1.0×10-9 over a period of several hours.