Details

Autor(en) / Beteiligte

• Deninger, Anselm J.
• Roggenbuck, A.
• Schindler, S.
• Preu, S.

Titel

2.75 THz tuning with a triple-DFB laser system at 1550 nm and InGaAs photomixers

Ist Teil von

• Journal of infrared, millimeter and terahertz waves, 2015-03, Vol.36 (3), p.269-277

Ort / Verlag

Boston: Springer US

Erscheinungsjahr

2015

Link zum Volltext

Quelle

SpringerLink

Beschreibungen/Notizen

• To date, exploiting the full bandwidth of state-of-the-art InGaAs photomixers for generation and detection of continuous-wave (CW) THz radiation (typ. ~50 GHz to ~3 THz) required complex and costly external-cavity diode lasers with motorized resonator control. Distributed feedback (DFB) lasers, by contrast, are compact and inexpensive, but the tuning range per diode is limited to ~600 GHz at 1.5 μm. In this paper, we show that a combination of three DFB diodes covers the complete frequency range from 0 – 2750 GHz without any gaps. In combination with InGaAs-based photomixers for terahertz generation and detection, the system achieves a dynamic range of > 100 dB at 56 GHz, 64 dB at 1000 GHz, and 26 dB at 2500 GHz. A field-programmable gate array (FPGA)-based lock-in amplifier permits a flexible adjustment of the integration time from 0.5 ms to 600 ms. Employing an optimized “fast scan” mode, a spectrum of ~1200 GHz – the bandwidth of each subset of two lasers – and 40 MHz steps is acquired in less than one minute, still maintaining a reasonable dynamic range. To the best of our knowledge, the bandwidth of 2.75 THz presents a new record for DFB-based CW-terahertz systems.