  Mid-wave infrared (MWIR) frequency comb is expected to dramatically improve
the precision and sensitivity of molecular spectroscopy. For high resolution
application, high speed MWIR photodetector is one of the key components,
however, the commercially available high speed MWIR photodetector only has
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{\mu}m, and 3dB
bandwidth of 6.58 GHz for a 20{\mu}m diameter device at 300K. These promising
results show 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.
