Open AccessHigh-speed quantum cascade detector characterized with a mid-infrared femtosecond oscillator
Author(s) -
Johannes Hillbrand,
Léonard M. Krüger,
Sandro Dal Cin,
Hedwig Knötig,
Jonas Heidrich,
A. M. Andrews,
G. Strasser,
U. Keller,
Benedikt Schwarz
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.417976
Subject(s) - optics , optoelectronics , detector , picosecond , femtosecond , quantum cascade laser , physics , bandwidth (computing) , laser , optical parametric oscillator , materials science , photodetector , local oscillator , cascade , telecommunications , phase noise , chemistry , chromatography , computer science
Quantum cascade detectors (QCD) are photovoltaic mid-infrared detectors based on intersubband transitions. Owing to the sub-picosecond carrier transport between subbands and the absence of a bias voltage, QCDs are ideally suited for high-speed and room temperature operation. Here, we demonstrate the design, fabrication, and characterization of 4.3 µm wavelength QCDs optimized for large electrical bandwidth. The detector signal is extracted via a tapered coplanar waveguide (CPW), which was impedance-matched to 50 Ω. Using femtosecond pulses generated by a mid-infrared optical parametric oscillator (OPO), we show that the impulse response of the fully packaged QCDs has a full-width at half-maximum of only 13.4 ps corresponding to a 3-dB bandwidth of more than 20 GHz. Considerable detection capability beyond the 3-dB bandwidth is reported up to at least 50 GHz, which allows us to measure more than 600 harmonics of the OPO repetition frequency reaching 38 dB signal-to-noise ratio without the need of electronic amplification.