High Speed Mid-Wave Infrared Uni-Traveling Carrier Photodetector

A mid-wave infrared (MWIR) frequency comb is expected to dramatically improve the precision and sensitivity of molecular spectroscopy. For high resolution applications, a high speed MWIR photodetector is one of the key components, however, commercially available high speed MWIR photodetectors only have sub-GHz bandwidth currently. In this paper, we demonstrate, for the first time to our knowledge, a high speed mid-wave infrared (MWIR) uni-traveling carrier photodetector based on InAs/GaSb type-II superlattice (T2SL) at room temperature. The device exhibits a cutoff wavelength of 5.6 μm and a 3dB bandwidth of 6.58 GHz for a 20μm diameter device at 300 K. These promising results show that the device has potential to be utilized in high speed applications such as frequency comb spectroscopy, free space communication and others. The limitations on the high frequency performance of the photodetectors are also discussed.