filtering the light 6 to obtain only the amplified signal light 9 using an optical filter 8 embodiment 3 shows a form of an optical circuit to be used in an optical signal regeneration circuit for implementing the present invention as described in literature 12 the optical regeneration circuit outputs an optical signal of which waveform is shaped with respect to an input signal light or extracts optical time division multiplexed signals the optical circuit that constitutes the optical signal regeneration circuit shown in fig2 of the literature 12 comprises as shown in the specification of the literature 12 a highly nonlinear medium for generating four wave mixing an optical filter for allowing only the idler light to pass therethrough and a pumping light source therefore the construction is the same as that of embodiment 1 in the literature 12 a semiconductor amplifier was used as the highly nonlinear medium by constituting the optical signal regeneration circuit shown in the literature 12 using the optical circuit of the configuration of fig1 a fiber optical signal regeneration circuit can be implemented embodiment 4 shows a form of a multi wavelength optical source for implementing the present invention fig3 is a conceptual view showing the.