Birefringent Etalon Research Articles

Modulation-Noise-Free Continuously Tunable Single-Frequency CW Ti:Sapphire Laser With Intracavity-Locked Birefringent Etalon

We present a continuously tunable single-frequency continuous wave (CW) Ti:Sapphire (Ti:S) laser with modulation-free-locked intracavity lithium niobate (LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) birefringent etalon (BE), which is implemented by detecting the polarization state variation of the reflected laser beam from the BE. After the BE is stably locked, the continuous frequency-scanning range up to 40 GHz is obtained within the tuning range of 300 nm while the resonator length of the Ti:S laser is continuously scanned. Because the modulation signal is unnecessary in the presented Ti:S laser system, the influences of the extra modulation signal on the intensity noise as well as the frequency noise of the laser are thoroughly eliminated and the modulation-noise-free continuously tunable single-frequency CW Ti:S laser is successfully attained.

A birefringent etalon as single-mode selector in a laser cavity

A novel technique is demonstrated for stabilizing an intra-cavity etalon used for single-mode selection in a laser cavity. By appropriate polarization analysis of the reflection from an etalon designed as a quarterwave plate an electronic signal can be derived, that enables the implementation of an electronic stabilization scheme. This scheme obviates the need for any modulation of the etalon in order to ensure stable single mode operation of a cw tunable laser.

Polarization spectroscopy applied to the frequency stabilization of rare-earth-doped fiber lasers: a numerical and experimental demonstration

The frequency response of a unidirectional ring laser containing a linear polarizer and a weakly birefringent etalon is analyzed numerically. The data obtained indicate that by sensing the changes in the polarization state of the light that is coupled from the etalon, a suitable error signal can be derived that can be used to prevent longitudinal mode hops. This idea is verified experimentally by configuration of an erbium ring fiber laser with a nonplanar 3×3 fused-fiber coupler to form the intracavity etalon. When the longitudinal mode hops are inhibited and the oscillating frequency of the fiber laser is locked to a reference confocal etalon, the resulting radiation has a linewidth of 14 kHz with an associated rms frequency jitter of 2 kHz.