What kind of output does this sensor have?
Like all photodiodes it is rated on A/W for IR input wavelengths and depends on aperture chip size w.
For mW of optical power it has very low sensitivity yet extremely fast response in ns.  So instead of a silicon diode of perhaps 0.5A/W it is 0.008 A/W for a 1mm aperture in one case.
The output is in uA/mW of IR power for use with a high speed transimpedance amplifier with a low source impedance from the detector.
It uses a special semiconductor for IR sensitivity