DEVICE FOR OBSERVING FUNCTION OF MANY CHANNELS OPTICAL SIGNAL IN WAVELENGTH DIVISION MULTIPLEXING SYSTEM

PURPOSE: A device for observing function of many channels optical signal in a wavelength division multiplexing system is provided to measure the function of the optical signal stably and dependably by materializing a simple circuit of the low cost. CONSTITUTION: The device for observing function of many channels optical signal in the wavelength division multiplexing system includes a wavelength variable filter(300), a Mach-Zehnder interferometer(310), the first optical detector(320), the second optical detector(330) and an optical signal function observing controller(340). The Mach-Zehnder interferometer(310) outputs characteristics of transmission differently according to the wavelength output in the wavelength variable filter(300). The first optical detector(320) converts the optical signal of a port output from the Mach-Zehnder interferometer(310) into the electrical signal and detects it and supplies the converted signal to the optical signal function observing controller(340). The second optical detector(330) converts the optical signal of the other port output from the Mach-Zehnder interferometer(310) into the electrical signal and detects it and supplies the converted signal to the optical signal function observing controller(340). The optical signal function observing controller(340) decides the optical strength and wavelength from the electrical signal output in the first optical detector(320) and the second optical detector(330).