Wavelength converter

A wavelength converter comprising:

• a port which receives an input signal pulse light at a pulse interval;
• a first and second non-linear waveguide, each non-linear waveguide having an input and an output;
• a light delay circuit which receives the input signal pulse light, branches the input signal pulse light into first and second signal pulse lights, adds a different delay to each of the two signal pulse lights by passing the signal pulse lights through optical paths of different lengths thereby producing delayed first and second signal pulse lights, transmits the delayed first signal pulse light to the first non-linear waveguide, and transmits the delayed second sional pulse light to the second non-linear waveguide;
• a continuous-wave light source which produces a continuous wave light signal;
• a branching section which branches the continuous wave light signal into a first continuous wave light signal and a second continuous wave light signal, the branching section further feeds the first continuous wave light signal to the input of the first non-linear waveguide and feeds the second continuous wave light signal to the input of the second non-linear waveguide;
• and
• a combiner section which combines the outputs of the first and second non-linear waveguides;
• wherein a condition ΔLd=vgTo/2 is satisfied, with ΔLd denoting the difference in the optical paths, To denoting the input signal pulse interval, and vg denoting a speed at which a signal pulse light proceeds through the light delay circuit.