Fast CW-THz System Employing a Dual Mode Y-Branch DFB Laser

We present a photonic CW-THz system operating at 1 THz capable of measuring the phase information of the THz path with a measurement rate of 10 kHz and micrometer precision. The 1 THz beating signal is generated in a monolithic dual mode Y-branch DFB laser, where one of the emission modes is tuned in wavelength by current density with a modulation frequency of 500 kHz. The system performance is demonstrated by sampling the position of a loudspeaker membrane through an optically opaque material.