Abstract
The generation of phase‐matched two‐wave sum‐frequency light is observed in optical fibers. A Q‐switched and mode‐locked Nd:YAG laser is used as a pump laser. The two‐wave sum‐frequency light is generated from the pump and the first two Roman Stokes lines. Phase matching is achieved by using the dispersion of the waveguide modes to compensate for bulk dispersion. Conversion efficiencies of 1.1×10−3 and 0.5×10−3 from the pump into the two‐wave sum‐frequencies, whose peak wavelengths are 0.54 and 0.56 μm, respectively, are obtained with an 0.8‐kW peak pump power at 1.064 μm.