Hi-Bi Sagnac interferometer application for wavelenght tuning in CW and actively Q-switched Erbium fiber laser

An experimental analysis for the use of a Sagnac interferometer with high birefringence fiber in the loop as generated laser wavelength tuning device in a ring cavity Erbium-doped fiber laser in continuous wave and pulsed actively Q-switched regimes is presented. The maximal tuning range of ~26.72 nm depends on the Sagnac interferometer wavelength spectrum period of ~30.32 nm. The wavelength tuning of the generated laser line is performed by wavelength displacement of Sagnac interferometer spectrum by temperature variations applied on the fiber loop. Experimental results of the laser spectrum in continuous wave and actively Q-switched operations, and Q-switched pulses characteristics are shown.