Frequency stabilization of a laser diode by means of an optical wedge etalon

Abstract

A novel laser diode (LD) wavelength stabilization system based on an optical wedge interferometer is presented. The proposed system uses an interference pattern from an external wedge etalon to detect frequency changes via a differential photodetector. Based on the etalon photodetector output signal, the feedback electronic circuit controls the LD current so as to obtain the LD wavelength as close as possible to the value set as a reference. Theoretical basis, design of the prototype system and metrological feasibilities of the device are presented. The absence of wavelength modulation during frequency stabilization, simplicity and low cost are the main advantages of the proposed technique.

Interference theory of multiple optical vortex states in spiral phase plate etalon: thick-plate and thin-plate approximation

“…When reflections off the surfaces of the SPP are considered, the device becomes a SPP etalon that forms a new etalon geometry [28] containing a coherent superposition of OAM states with welldefined phase relationship [28,29]. In order to extend the capabilities of this photonic device as a useful tool in precision optical frequency metrology such as laser locking and stabilization systems [30][31][32][33], optical gyroscopes for rotation sensing, optical resonators [34], quantum cavity electrodynamics [35] with OAM modes, atom circuits [36,37], and other areas of device physics and metrology, it becomes important to understand transmission through the SPP etalon in different regimes, i.e., from the low-reflectivity (low-finesse) to high-reflectivity (high-finesse) regimes.…”

Multiple-beam interference in a spiral phase plate

“…The orientation of this interference pattern rotates when the laser frequency is varied such that it may be of practical importance in the area of frequency metrology. Wedge etalons, i.e., etalons with a thickness that varies linearly as a function of spatial coordinate along one axis, have been used for this purpose previously [43,44].…”

Laser diode distance measuring interferometer - metrological properties

“…Wavelength instability and reproducibility of the LD was tested by comparison of the instantaneous values of the LD wavelength with the wavelength of a reference stabilized HeNe laser in vacuum. For this purpose we used a specially designed interferometric vacuum wavelength comparator [17,18]. The measurement relative uncertainty of the comparator was equal to about 3×10 -9 (range).…”

“…We developed the idea of applying an uncoated glass etalon as a reference interferometer for LD frequency stabilization [17,18].The proposed system uses an interference pattern from the external wedge etalon to detect wavelength (frequency) changes via a differential photodetector. An electronic circuit controls the LD current in the feedback loop so as to obtain the LD wavelength as close as possible to the value set in the calibration procedure.…”

“…A more detailed description of the proposed technique has been presented in [17,18]. Basing on this stabilization method we have developed a small and compact, inexpensive laser diode based interferometer similar in general design to standard commercially available HeNe laser interferometers.…”