This unit has a wide-bandwidth, sensitive O/E converter for characterizing lightwave systems and components, it combines a PIN photodetector with a low noise DC coupled preamplifier to create a general purpose front end. It covers wavelengths from 1200 to 1600 nm and bandwidths from DC to 15GHz. With 300 V/W conversion gain and 0.05 percent input optical reflections, it significantly improves the sensitivity of the measurement system. The converter comes with a calibration chart of instrument specific data for making corrected frequency response measurements.