Single mode optical fiber nonlinear coefficient measurement based on four wave mixing method with novel two-tone optical source

In this paper novel two-tone optical source for determination of single-mode optical fiber nonlinear coefficient is presented and discussed. In novel proposed measurement scheme two wavelengths of light are generated by two-tone optical source. Presented two-tone nonlinear coefficient meter achieves high peak power using pulsed operation. Both the two-tone generation and the pulse modulation are obtained from a single LiNbO₃ modulator, driven by standard microwave pulse generator. The obtained two optical signals have inherently the same linear polarisation. The frequency spacing is precisely set by the modulation signal and no adjustment is required during the measurement because there is no wavelength difference drifting.