Optical filter module and optical amplification using it

Abstract

In an optical filter module and an optical amplification apparatus for a wavelength division multiplex (WDM light), the respective wavelength intervals of the plural passing center wavelengths and the filter characteristics in the vicinities of the respective center wavelengths can be set independently, whereby the BPF1 is provided with different passing center wavelengths .lambda.1, .lambda.2 . . . .lambda.n and different filter characteristics. And, when the WDM signal light including wavelengths .lambda.1, .lambda.2 . . . .lambda.n is inputted into the port 2-1a, the .lambda.k (k=1,2 . . . n) component is transmitted by the corresponding BPF1-k, and the transmitted light is multiplexed sequentially and outputted from the port 2-nb and the other wavelength components (noise light components) are reflected by all of the BPFs and outputted from the port 2-nc. When the WDM signal light including wavelengths except for .lambda.1, .lambda.2 . . . .lambda.n is inputted into the port 2-nc, the component of the wavelength .lambda.n (noise light component) is outputted from the port 2-1d and the other wavelength components are outputted from the port 2-1a. And, the optical coupler 6 monitors the output light of the BPF 1 to perceive the levels of the respective wavelength components in the WDM signal light.