| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical wavelength filter and an optical demultiplexer useful for an optical transmitter which uses a low-loss and high-density wavelength division multiplexing method. SOLUTION: The optical demultiplexer consists of many optical wavelength filters 700, 800,...900 mutually connected and constituted in series, and the optical wavelength filter 700 includes a first input port 701 for receiving incident light signals, a first output port 702 for outputting light signals with a prescribed wavelength of incident light signals, and a second output port 703 for outputting residual light signals without having a prescribed wavelength of incident light signals. Each optical wavelength filter 700, 800,...900 receives light signals which have various wavelength components λ1, λ2,...λn, separates light signals with a wavelength component from the light signals, outputs the separated light signals to first output ports 702, 802,..., 902, respectively, and outputs light signals with other wavelength component to second output ports 703, 803,..., 903, respectively. The light signals outputted to the second output ports are again entered into the input ports of the optical wavelength filter which are connected in series with the second output ports respectively in order to separate light signals which have other wavelength component. |
