OPTICAL ROUTERS

摘要

An optical router (100) comprises a planar waveguide circuit 101 having two inputs (102) and (103) for receiving multiplexed DWDM signals from respective optical fibres, and two outputs (104) and (105) for supplying output DWDM signals to output optical fibres and/or further optical circuits. Each of the inputs (102) and (103) incorporates respective LOAs (106) and (107) for amplifying the optical input signals prior to supplying the signals to star couplers (108) and (109) for routing of the signals along waveguides (110, 111) or (112, 113) towards the two outputs (104) and (105). Each of the waveguides (110, 111, 112) and (113) incorporates a respective EVOA (114, 115, 116, 117) which is actuable by an electrical control signal to attenuate the signal transmitted along the waveguide. The waveguides (110) and (112) are coupled to a further star coupler (118), and the waveguides (111) and (113) are coupled to a further star coupler (119). As a result the output (104), for example, receives either a signal from the star coupler (108) or a signal from the star coupler (109), depending on whether the EVOA (114) or the EVOA (116) effectively blocks the corresponding signal. It will therefore be appreciated that the EVOAs (114, 115, 116) and (117) are controllable by electrical control signals in such a manner as to route the appropriate input signal to the required one of the outputs with the unwanted signal paths being effectively blocked by the corresponding EVOA. Such a router can be readily fabricated in planar waveguide circuitry so as to simplify the fabrication of the device and decrease its cost as compared with conventional devices.