| 摘要 |
PURPOSE:To realize an economical transmission system with good separation secured between the uptransmission and the down-transmission, by using the LED possessing the luminous spectra having the partial overlap each other plus the optical filters which have no mutual overlapping pass bands substantially. CONSTITUTION:The electric signals applied to input terminals 9 and 10 of optical transmitters 1 and 2 are amplified by driving circuits 5 and 6 each and then applied to LED7, 8 to be turned into the photosignals. The luminous center wavelength differs slightly between LED7, 8, and their luminous spectra overlap partially. The optical signals of LED7, 8 enter optical filters 3 and 4 each, and only a part of the luminous spectra passes through the filter to then enter two-way separating circuit 11 to be sent finally to optical fiber 12. In this case, the pass bands must not overlap substantially and mutually between filters 3 and 4. Accordingly, the luminous spectra have no overlap substantially between the photosignal passed through filter 3 and that passed through filter 4. As a result, the good separation is possible between the uptransmission and the down-transmission. |
