Yoshitaka TAKAHASHI,^* Toshihiko YOSHINO and Kazuyoshi HORIE^*

Department of Electronic Engineering, Faculty of Engineering, Gunma University, 1-5-1, Tenjin-cho, Kiryu, Gunma, 376 Japan

(Received January 8, 1997; Accepted March 26, 1997)

A diode ring cavity incorporating Faraday rotators and a variable phase retarder has been constructed aiming at achieving dual-frequency lasing operation with orthogonal linear polarizations. The orthogonal-polarization oscillations were observed in the 0.8-μm region with various operation wavelengths by changing the applied retardation. Furthermore the output power definitely depended on the applied retardation. Its dependence was theoretically studied, and the gain analysis taking into consideration the reflection at the laser diode amplifier facets was in good accordance with the experimental results.

Key words : ring laser, laser diode amplifier, frequency control, optical sensing, optical heterodyne sensing