Patent ID: 6538782
Filing Date: 2003-03-25
Classification: H04J

Abstract:
A light branching/inserting apparatus using a wavelength selection filter, said apparatus comprising:branching/inserting means connected to a transmission path through which wavelength division multiplexed light signals are transmitted, which is capable of branching and inserting light signals having at least one wavelength with respect to light signals on said transmission path; light branching means for receiving and processing light signals branched by said branching/inserting means for each wavelength; and light inserting means for outputting insertion light to be inserted into the light signals on said transmission path to said branching/inserting means, wherein said branching/inserting means includes a wavelength selection filter which can generate a surface acoustic wave of a frequency corresponding to a selection signal, and which has an input port to which a light signal received from the transmission path is input, an output port from which a light signal to be output to the transmission path is output, a branching port connected to said light branching means and an insertion port connected to said light inserting means, and said wavelength selection filter is applied with said selection signal and branches a light signal having a wavelength corresponding to the frequency of said surface acoustic wave contained in the light signal which is sent to said input port from said transmission path and outputs the branched light signal to said branching port, and also inserts insertion light having a wavelength corresponding to the frequency of said surface acoustic wave and which is sent to said insertion port, into the light signal from said transmission path and outputs the light signal to said output port, and said branching/inserting means further comprises a monitoring means for respectively measuring a spectrum of the light signal input from said transmission path to said input port of said wavelength selection filter and a spectrum of the light signal output from said output port of said wavelength selection filter to said transmission path, to monitor the light power of each wavelength and thereby determine whether the wavelength selection filter is operating properly.