Patent ID: 7525725

Claim:
An optical amplification module having an amplification band within a range of 1490 nm to 1520 nm, comprising: an Er-doped optical waveguide having an optical waveguide region doped with Er; a pumping light source optically connected to one end of said Er-doped optical waveguide through an optical coupler, whereby pumping light generated in said pumping light source is supplied into said Er-doped optical waveguide; a temperature adjustor including a section which is arranged adjacent to said Er-doped optical waveguide, said temperature adjustor adjusting a temperature of said Er-doped optical waveguide and maintaining the temperature of said Er-doped optical waveguide at a predetermined temperature higher than room temperature, on the basis of the result of the detection; and a cutoff filter provided on an optical path between an input end and an output end of said optical amplification module, said cutoff filter cutting off light in a wavelength band of 1530 nm or more so as to remove amplified spontaneous emission light in C-band.