| 摘要 |
PURPOSE:To obtain an optical demultiplexer/multiplexer for multiplexing of wavelength having excellent cross talk properties, by combining a short wavelength pass filter and a long wavelength pass filter at the front of a coupling lens of transmitting and receiving elements. CONSTITUTION:The light of a short wavelength lambda1 passes through the short wavelength pass filters (SWPF) 2 and 1 via a rod lens 4 from a light emitting element and then enters an optical fiber transmission line 13 via a rod lens 5. The light of a long wavelength lambda2 sent from the line 13 is reflected by the SWPF1 and passes through a long wavelength pass filter (LWPF)3 and enters a photodetector via a rod lens 6. The wavelengths lambda1 and lambda2 plus the SWPF and LWPF are exchanged with each other between the SW type of the long wavelength reception and the LW type of the short wavelength reception. The LWPF1 and SWPF9 that cut the light lambda1 and lambda2 respcetively are provided at the front of rod lenses 3 and 11 respectively for both SW and LW types. Thus the excellent cross talk properties can be obtained for an optical demultiplexer/ multiplexer for multiplexing of wavelength. |
