The AQ6377 from Yokogawa Electric is an Optical Spectrum Analyzer for environmental sensing and medical applications. It offers extended wavelength coverage in the MWIR region from 1900 to 5500 nm with a wavelength resolution of 0.2 to 5 nm. This spectrum analyzer has a wide measurable level range from −60 to 13 dBm and a dynamic range of 50 dB. It features gas purging input /output ports, a built-in cut filter for high order diffracted light, and a novel double speed mode which increases the sweep speed up to 2 times compared to the standard sweep mode. The device uses a free-space optical input structure and accepts both /PC and /APC connectors.