Optical injection and mode-coupling effects in two-color lasers

Laser designed to emit at multiple and controllable modes, or multi-wavelength lasers, have the potential to become key building blocks in future compact THz or mm-wave transceivers. Combined with optical injection, these lasers can function as low-noise THz sources or even enable all-optical THz signal processing. Among the various multi-wavelength laser concepts, DBR-based lasers stand out because of their simplicity principle to control and switch the output wavelength of the laser. The extra wavelengths also add new degrees of freedom and interesting new features for laser dynamics. Yet, the coupling between the different laser modes has not been carefully considered so far. Here, we experimentally and numerically analyze the effect of nonlinear mode coupling and interactions in a dual-wavelength laser under optical injection. We focus particularly on the evolution of the locking bandwidth for different gain coefficients between the injected and non-injected modes. In addition, we report a wavelength shift of the non-injected mode which follows the evolution of the detuning in the other mode. Our work brings a new important insight into the mode competition taking place in multi-wavelength lasers, pushing them forward towards novel applications.