The D-8ir is a 50 GHz detector designed for 950–1650 nm measurement applications where an instrument-style product is desirable. The D-8ir provides a peak responsivity of 0.7 A/W at 1310 nm with an ultrafast impulse response of 8 ps. The internal Clean-pulseTM design assures low group-delay response necessary for time-domain, digital applications. This instrument provides a high performance PIN detector in a hand-held, rugged, black-anodized case. The case contains the detector module, power conditioning circuitry, photocurrent monitor, fiber optic input port, and Anritsu K output connector in addition to a power switch and battery indicator light. Designed with R&D applications in mind, it can be attached to virtually any diagnostic instrument to provide optical capability.