We have demonstrated four-wave mixing in multiple-quantum-well (MQW) GaAlAs-laser diodes (LD) by injecting two narrow-band signals from optically/electronically stabilized LDs into a mixer LD. S/N-ratios of the heterodyne-detected mixing signals were measured for frequency differences (delta) (nu) between the pump-lasers up to the THz-range being sufficient for phase-coherent optical frequency synthesis. The measured dependence of the mixing signal S/N ratio on (delta) (nu) indicates a intraband population relaxation time T1 <EQ 200 fs. Schemes for dividing an optical frequency interval into two or three equal parts are discussed. Furthermore, all-optical frequency interval bisection is demonstrated for the first time.
Harald R. Telle,
"Coherent four-wave mixing in laser diodes", Proc. SPIE 1837, Frequency-Stabilized Lasers and Their Applications, (30 April 1993); doi: 10.1117/12.143696; https://doi.org/10.1117/12.143696