Two-Wavelength Switching With a 1550 nm VCSEL Under Single Orthogonal Optical Injection

We report the first experimental observation of three distinct forms of two-wavelength switching (clockwise, anticlockwise, and butterfly) for a 1550 nm vertical cavity surface emitting laser (VCSEL) operated just above threshold and subject to orthogonally polarized optical injection. The spectrum of the device exhibits two modes, a main mode emitting in a "parallel'' polarization and a subsidiary "`orthogonal'' polarized mode. Low input-power switching of the emission wavelength of the VCSEL by an orthogonally polarized external optical signal injected to the long-wavelength side of the subsidiary mode is observed. Clockwise switching and bistability of the main lasing mode with very high on-off contrast ratio has been measured in all cases. Three different switching shapes: anticlockwise, butterfly, and clockwise, have been measured for the output of the optically injected VCSEL. This diversity of switching behavior with a 1550 nm VCSEL subject to optical injection offers promise for the use of these devices in all-optical switching/routing as well as optical interconnect applications.