| 摘要 |
In the demultiplexer device 19, couplers 20-22 are disposed in multi stages. To one branch of each coupler, optical bandpass filters 15-17 are connected. To the other branches, equalizing fibers 2, 23-25 are connected. The final equalizing fibre 25 has an additional optical filter 18, for the shortest wavelength signal, connected. Optical amplifiers 3, 26 are disposed at predetermined points. If a wavelength division multiplexed signal is inputted at point 1, dispersion and loss compensated demultiplexed signals S1-S4 are outputted as shown. This arrangement means that the equalizing fibers 2, 23-25 act to perform accumulative dispersion compensation. Consequently, the number of equalizing fibres required is reduced, resulting in less attenuation allowing the number of optical amplifiers to be reduced as well. Thus the device achieves efficient dispersion and loss compensation using less optical components. The filters 15-18 may be dielectric filters or optical circulator/fibre grating combinations. |
