| 摘要 |
A wavelength-division-multiplexed transmitter has a single modulator modulating the output of an array of individually actuable semiconductor lasers (LA1,...,LA8) integrated onto the same substrate as the modulator. An optical combiner (CO1) integrated onto the same substrate between each of the lasers and the single modulator combines the outputs of the lasers. One or more of the lasers are activated as desired for wavelength division multiplexing. The modulator (MOD1) is a directional coupler modulator, a Mach-Zehnder modulator, or any other suitable optical modulator. The lasers (LA1 to LA8) are distributed Bragg reflector (DBR) lasers or distributed feedback (DFB) lasers. They may be any other form of optical laser having a controlled emission wavelength. The combiner (CO1) is in the form of a slab waveguide region without lateral confinement of the light to allow diffraction in the plane of the wafer. Each waveguide (W1 to W8) entering the free-space region on the input sided has a far field that illuminates the output waveguide (OW1) on the output side. With one output waveguide, this device is a 1 x 8 power combiner. In a more general form such combiners have more than one output. With N inputs and N outputs the combiner makes an N x N star coupler. In an embodiment of the invention, the combiner (CO1) takes the form of an N x N star coupler and uses only one of the output waveguides. <IMAGE> |
