We demonstrate the generation of cw millimeter-wave signals in LN optical channel waveguides using optical technology. The spectral linewidth of the generated millimeter-wave signals is 2 kHz. The power of the measured cw millimeter-wave signals is almost in proportion to the power multiplication of two input optical signals. In this experiment, the frequency difference of two optical signals is 10 to 40 GHz, and the power of millimeter-wave signals showed variation within 4 dBm.
"Generation of continuous-wave millimeter-wave signals in a nonlinear lithium niobate optical waveguide," Optical Engineering 41(10), (1 October 2002). https://doi.org/10.1117/1.1503808