Polarization Characteristics of an External Cavity Diode Laser With Littman–Metcalf Configuration

Polarization characteristics of an external cavity diode laser (ECDL) in Littman configuration with a diffraction grating are presented in this letter. Using a conventional analyzer, it is found that both linear polarized and elliptical polarized (EP) emission can be obtained from the ECDL. It is also an EP state in the laser cavity when the output is in EP state. Experimental results indicate that the grating we used is a polarization-conversion element for both of the zeroth- and first-order diffractions. Brief explanations and basic equations are given in this letter.