Room-Temperature, Wide-Band, Quantum Well Infrared Photodetector for Microwave Optical Links at 4.9 μm Wavelength

Abstract

High-speed, room-temperature, quantum well infrared photodetectors (QWIPs) at λ ∼ 4.9 μm have been realized in a strain compensated In 0.1 Ga 0.9 As/Al 0.4 Ga 0.6 As heterostructure grown on a GaAs substrate. The high-speed properties at room temperature have been optimized by using a specifically designed air-bridge structure, which greatly reduces the time constant of the effective RC circuit, thus, allowing transmission and detection of high-frequency signals. By modulating a high-speed quantum cascade laser (QCL) centered at λ ∼ 4.7 μm, we were able to record a modulation of the photocurrent up to ∼26 GHz, which is limited by our setup. At 300 K and under a bias voltage of −5 V our device shows high responsivity and detectivity of 100 mA/W and 1 × 10 7 Jones, respectively. The developed high-performance QWIPs at this wavelength are highly promising for optical heterodyne measurement, high-speed free space communications in microwave optical links and frequency comb QCLs characterisations.

Tunability of the Free‐Spectral Range by Microwave Injection into a Mid‐Infrared Quantum Cascade Laser

“…Coupled with the newly developed wide‐band quantum well infrared photodetectors (QWIPs), they pave the way toward microwave optical links in the atmospheric window. [ 15 ] For instance, recently, Pfeifle et al. have achieved a data transfer rate of 1.44 Tbit s −1 over up to 300 km by using near‐infrared frequency comb sources, [ 16 ] demonstrating the capability of frequency comb in free‐space communication applications.…”

Ultrafast Quantum-Well Photodetectors Operating at 10 μm with a Flat Frequency Response up to 70 GHz at Room Temperature

“…With these devices we demonstrate room temperature heterodyne detection at 10.3 µm with a nearly flat frequency response up to 70GHz (limited by the detection electronics), and state of the art responsivities of ~0.15A/W. To the best of our knowledge this represents the broadest experimental RF bandwidth reported to date for a QWIP detector [6,7,21], and extends by over 65 GHz the results presented in Ref. [20].…”

Chaos Bandwidth in Mid-infrared Quantum Cascade Photonic Devices with Interband and Intersubband Transitions

“…Up to date, very few high-speed detectors in the mid-IR exist, and it is even more challenging to have some working at room-temperature. Further studies of the ICL chaos will be performed using wavelength up-conversion sensors and quantum well infrared photo-detectors [8] in order to access the whole characteristic of the signal. For both semiconductor lasers, the chaotic nature of the waveform is assessed by the derivation of the largest Lyapunov exponents (LEs) [9].…”