All-optical shutter and polarizer using Fabry Perot laser diode.

摘要

Optical networks utilizing fast packet switching are expected to provide the required capacities and flexibility in the next generation high-speed optical networks. A variety of all-optical switching devices using nonlinear interferometers and wavelength conversion have been reported. Here an all-optical shutter using the mutual injection-locking principle of a Fabry Perot laser diode (FP-LD) is demonstrated. When an input signal with a particular wavelength detunes and relevant power is injection-locked close to one of the modes of the FP-LD it experiences a mode-shift. When two signals are injection-locked by a FP-LD, the control signal can switch data ON and OFF because of the mode-shift effect. In the absence of the control signal, data is switched ON and in the presence of the control signal, data is switched OFF. An extinction ratio of 16.9 dBm at the switched 10 Gb/s data-rate was obtained for a 3 dB difference in the power of the control signal. The switch-on and switch-off time was reported to be ∼60 ps and ∼50 ps respectively and hence the data is switched within one bit period.; Real-time automatic polarization stabilization is crucial to the deployment of all-optical switches, add-drop multiplexers, polarization-multiplexed systems, and coherent detection systems in optical networks. Most of the polarization control schemes proposed to date comprise a polarization rotation unit and a complex feedback control unit. Polarization control is carried out either mechanically (e.g., fiber squeezers/paddles, MEMS) or electro-optically (e.g., liquid crystal or electro-optics crystal and PM-segment fibers). We demonstrate that a mutual injection-locked laser diode functions as an all-optical polarization controller and can be used to re-polarize 10 Gb/s polarization-scrambled NRZ signals. The mutual injection-locked laser diode controls the state-of-polarization (SOP) of the input signal, not by rotating its SOP, but by functioning as intensity-compensating polarizer. Thus neither complicated SOP characterization nor a speed-limiting feedback control process is required. We further demonstrate how a single mutual injection-locking laser diode can simultaneously realign the polarizations of two polarization scrambled 10 Gb/s signals. (Abstract shortened by UMI.)