OPTICAL WAVELENGTH MULTIPLEX TRANSMITTER

摘要

PURPOSE:To suppress effectively crosstalk attenuation at a photodetector by adopting the constitution that a band pass filter is provided to each of light emitting element and the photodetector and a low pass filter and a high pass filter using a common adjacent transmission region of each band pass filter as the attenuation region. CONSTITUTION:The high pass filter (SWPF)7a and the low pass filter (LWPF)8a are filters using a region where adjacent transmission region of band pass filter (BPF)5b and BPF6c are overlapped as the attenuation region respectively. Filters SWPF7b and LWPF8b are filters using a region where the adjacent transmission regions of the BPF5c and BPF6b are overlapped as the attenuation region. Since the SWPF7a and LWPF8a reflect respectively the transmitted light through the common adjacent transmission regions to the BPF5b and BPF6c, the incident of the light of a light emitting element 3a into a photodetector 4b is blocked. Since the SWPF7b and LWPF8b reflect the transmitted light through the common adjacent transmission region of the BPF5c and BPF6b, the incidence of the light of the light emitting element 3b into the photodetector 4a is blocked.