Patent attributes
For use in combining and/or splitting a 3-wavelength multiplexed light, in which if central wavelengths of the three bands are denoted as λ1, λ2 and λ3, in a relation that 0.92≦λ2/λ1≦1.08, 0.20≦λ3/λ1≦0.92 or 1.08≦λ3/λ1≦5.00, the wavelength multiplexing and demultiplexing device comprises two optical filters of different characteristics, supported by one of more optical substrates combined in a single package, wherein, when a 3-wavelength multiplexed light is led to a first filter A for splitting the 3-wavelength multiplexed light into light of a band of λ3 and a 2-wavelength multiplexed light of λ1 and λ2, and when the 2-wavelength multiplexed light is led to a second filter B for splitting the 2-wavelength multiplexed light into light of a band of λ1 and light of a band of λ2, an optical edge filter is used for the filter A and an optical band-pass filter is used for the filter B.
