Data wavelength conversion over THz range using an optical-feedback-controlled InP multimode laser

All-optical wavelength conversion is a key functionality for large WDM networks with dynamic traffic, e.g., to enable flexible wavelength allocation within the subnetworks. All-optical techniques mostly rely on exploiting the nonlinearities in semiconductor optical amplifiers, such as gain-saturation, FWM, and difference-frequency generation. These methods, however, require additional probe laser, or phase matching. Here we describe an alternative approach based on a feedback-controlled integrated DBR-based multi-wavelength laser (MWL). Our MWL is designed to emit at multiple and controllable modes, thus removing the need for an additional external probe light. Injecting an optical signal around one of the modes of the MWL leads to the spectral multiplication of the signal to the other modes of the MWL. By varying the phase and amplitude of the feedback we show frequency conversion of a 1 GBd ASK signal at offsets ranging from tens of GHz to 1.2 THz. The emission of the MWL can be controlled at nanosecond time scales by changing the feedback phase from a monolithically-integrated feedback cavity. Our approach is, in principle, only limited by the gain bandwidth of the active medium which can reach up to 10 THz in InP.