Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
280 words
A method of manufacturing an optical filter to be used in an optical amplifier equipped with an erbium-doped fiber that is excited by an pump light source, in a wavelength division multiplex transmission system, wherein the optical filter is manufactured by setting input signal light power, pump light source output power, and output signal light power of the optical amplifier respectively to power values used during operation in a communication system and setting the total power of a plurality of test input light, which includes simulation input light of a plurality of wavelengths and input light of one of the wavelengths in the communication band of the wavelength division multiplex transmission system, equal to the total power of communication input signals of a plurality of wavelengths used in the wavelength division multiplex transmission system, then performing variable adjustment in the above settings to determine the amount of attenuation from the light source to the input end of the optical amplifier in correspondence to the input light, among the test input light, of a wavelength in the communication band that is within or equal to a preset range or preset value in the range defined by the maximum and minimum output power from the same optical amplifier which corresponds to the amplified simulation input light, then repeating this determination of attenuation amount by variable adjustment in likewise manner to determine attenuation amounts that are in one-to-one correspondence with each wavelength of specified band within the wavelength division multiplex communication band, and then setting the loss spectrum of the optical filter so that the loss spectrum will be that of said attenuation amounts in one-to-one correspondence with each wavelength of specified band.
Claim 2
Independent Claim
280 words
A method of manufacturing an optical filter to be used in an optical amplifier equipped with an erbium-doped fiber that is excited by an pump light source, in a wavelength division multiplex transmission system, wherein the optical filter is manufactured by setting input signal light power, pump light source output power, and output signal light power of the optical amplifier respectively to power values used during operation in a communication system and setting the total power of a plurality of test input light, which includes simulation input light of a plurality of wavelengths and input light of one of the wavelengths in the communication band of the wavelength division multiplex transmission system, equal to the total power of communication input signals of a plurality of wavelengths used in the wavelength division multiplex transmission system, then performing variable adjustment in the above settings to determine the amount of attenuation from the light source to the input end of the optical amplifier in correspondence to the input light, among the test input light, of a wavelength in the communication band that is within or equal to a preset range or preset value in the range defined by the maximum and minimum output power from the same optical amplifier which corresponds to the amplified simulation input light, then repeating this determination of attenuation amount by variable adjustment in likewise manner to determine attenuation amounts that are in one-to-one correspondence with each wavelength of specified band within the wavelength division multiplex communication band, and then setting the loss spectrum of the optical filter so that the loss spectrum will be that of said attenuation amounts in one-to-one correspondence with each wavelength of specified band.
Claim 3
Dependent Claim
11 words
An optical filter manufactured by the manufacturing method of claim 1.
Claim 4
Dependent Claim
38 words
An optical amplifier for wavelength division multiplex communication which uses an erbium-doped fiber excited by an pumping light source, wherein the optical filter of claim 2 is inserted in the light path that passes through the erbium-doped fiber.
Claim 5
Dependent Claim
46 words
An optical amplifier for wavelength division multiplex communication systems which uses an erbium-doped fiber excited by an pumping light source, wherein a single-mode optical fiber is connected to the erbium-doped optical fiber and the optical filter of claim 2 is inserted in this single-mode optical fiber.