Transverse Mode Switching and Locking in Vertical-Cavity Surface-Emitting Lasers Subject to Orthogonal Optical Injection

• Published in: IEEE journal of quantum electronics Vol. 43; no. 4; pp. 322 - 333
• Main Authors: Valle, A., Gatare, I., Panajotov, K., Sciamanna, M.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2007; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers
• Subjects: Bistability; Engineering Sciences; Frequency; Injection locking; Laser mode locking; Laser modes; Laser theory; Lasers; nonlinear dynamics; Optical bistability; Optical losses; Optical polarization; Optical switches; Optics; Photonic; Physics; Polarization; polarization switching; Spectra; Strength; Surface emitting lasers; Switches; Switching; transverse modes; Vertical cavity surface emission lasers; Vertical cavity surface emitting lasers; vertical-cavity surface-emitting laser (VCSEL); laser cavity resonators; surface emitting lasers; laser modes; light polarisation; optical switches; laser mode locking; optical bistability; semiconductor lasers
• ISSN: 0018-9197; 1558-1713
• DOI: 10.1109/JQE.2007.893004

In this paper, we report on theoretical and experimental investigation on polarization and transverse mode behavior of vertical-cavity surface-emitting lasers (VCSELs) under orthogonal optical injection as a function of the injection strength and of the detuning between the injection frequency and the free-running frequency of the solitary laser. As the injection strength increases the VCSEL switches to the master laser polarization. We find that the injection power necessary to obtain such polarization switching is minimum at two different values of the frequency detuning: the first one corresponds to the frequency splitting between the two linearly polarized fundamental transverse modes, and the second one appears at a larger positive frequency detuning, close to the frequency difference between the first-order and the fundamental transverse modes of the solitary VCSEL. We show theoretically that both the depth and the frequency corresponding to the second minimum increase when the relative losses between the two transverse modes decrease. Bistability of the polarization switching is obtained for the whole frequency detuning range. Such a bistability is found for the fundamental mode only or for both transverse modes, depending on the value of the detuning. The theoretical and experimental optical spectra are in good agreement showing that the first-order transverse mode appears locked to the external injection