The 102X Series of time-domain-optimized photodetectors from New Focus Inc. offers 12-ps FWHM impulse responses and is suited for high-speed digital fiber optic systems, pulsed laser measurements and high-speed modulator characterization. These compact instruments are fabricated from an InGaAs Schottky diode. They are optically pigtailed and battery-powered with their own bias circuits and DC-power monitors. FC- and ST-connectorized versions are available, and both are terminated internally at 50 (omega), eliminating the need for a 6-dB attenuator with microwave filters. Additional benefits include <15% overshoot, 45-dB dynamic range, and responsivities of 0.4 and 0.3 A/W at 1310 and 1550 nm, respectively.