Monolithically integrated optical beat sources toward a single-chip broadband terahertz emitter

We have developed a 1.3??m phase-shifted dual-mode laser diode (pDML) for a tunable continuous-wave terahertz (CW THz) emitter. The mode beat frequency of the pDML is continuously tuned from 250 to 1480?GHz by introducing monolithically integrated micro-heaters and multiple sections to an all-active structure. The pDML shows a narrow spectral linewidth and a strong four-wave mixing signal throughout the entire tuning range. By?combining InGaAs based photomixers, we have successfully generated continuous-wave THz radiation, and confirmed the precise beat frequency settings and fast sweeping of this. This pDML operating at 1.3??m shows excellent performance in terms of THz conversion efficiency, tuning range and thermal stability.