Mid-wavelength infrared high-operating temperature detector for integrated photonics

In this work, we demonstrate a mid-wavelength infrared (MWIR) high-operating-temperature barrier infrared detector (HOT-BIRD) designed for integration with waveguide-based spectrometers on photonic integrated circuits, referred to as HOT-BIRD-IP. These detectors incorporate several key features: (1) a geometry suitable for side illumination, in contrast to conventional front- or back-illuminated designs; (2) an architecture tailored for efficient optical coupling from waveguides while minimizing dark current; and (3) electrical contacts and a mechanical support structure that enable integration with photonic chips via metal-to-metal bonding. The HOT-BIRD-IP detectors, with a cutoff wavelength of λ  = 5.5 μm at 150 K, operate in the temperature range 77–273 K, exhibiting a quantum efficiency of approximately 30% and a dark current density of jd ≈ 0.2 A/cm2 at T = 250 K. This demonstration represents an important step toward extending photonic integrated circuit technologies into the MWIR spectral range and enabling compact, on-chip spectrometers for chemical detection and identification.