Continuous Wave THz System Based on an Electrically Tunable Monolithic Dual Wavelength Y-Branch DBR Diode Laser

J.O. Gwaro1, C. Brenner1, L.S. Theurer2, M. Maiwald2, B. Sumpf2, M.R. Hofmann1

Published in:

J. Infrared Milli. Terahz. Waves, vol. 41, no. 5, pp. 568-575, DOI: 10.1007/s10762-020-00676-4 (2020).

Copyright © The Author(s) 2020.
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Abstract:

We analyse the use of a tunable dual wavelength Y-branch DBR laser diode for THz applications. The laser generates electrically tunable THz difference frequencies in the range between 100 and 300 GHz. The optical beats are tuned via current injection into a micro-resistor heater integrated on top of one of the distributed Bragg reflector (DBR) section of the diode. The laser is integrated in a homodyne THz system employing fiber coupled ion-implanted LT-GaAs log spiral antennas. The applicability of the developed system in THz spectroscopy is demonstrated by evaluating the spectral resonances of a THz filter as well as in THz metrology in thickness determination of a polyethylene sample.

1 Institute for Photonic and Terahertz Technology, Ruhr University Bochum, Universitätsstraße 150, 44780 Bochum, Germany
2 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany

Keywords:

Semiconductor laser, CW THz source, Homodyne detection.