| 摘要 |
PROBLEM TO BE SOLVED: To eliminate a frequency shift in the entire signal band, reduce the occurrence of excessive noise attributable to phase conjugate light conversion, and compensate for nonlinear noise every span of a transmission path due to inverse transmission characteristic.SOLUTION: A wavelength separation filter 101, a wavelength multiplex filter 102, a first nonlinear optical device 103, and a second nonlinear optical device 104 are included. The wavelength separation filter 101 separates a wavelength division multiplexed signal (WDM signal) into a short wave-side component and a long wave-side component. The nonlinear optical device 103 (104) multiplexes the short wave-side (long wave-side) component of the WDM signal with excitation light and then generates the phase conjugate light of the short wave-side (long wave-side) component by difference frequency generation and also separates the excitation light. The wavelength multiplex filter 102 multiplexes only the phase conjugate light of the short wave-side) component and the phase conjugate light of the long wave-side component of the WDM signal among input lights from the nonlinear optical devices 103, 104, to obtain an output light.SELECTED DRAWING: Figure 1 |
