The JDSU ETX 500T and ETX 1000T series large-area InGaAs PIN photodetectors have photosensitive areas with diameters of 500 and 1000 m, respectively. These photodiodes offer high responsivity in the 800 1700 nm spectrum, and are designed for use in instrumentation, sensing, and rangefinding applications. The detectors feature high sensitivity and linear spectral responsivity over a broad range of input powers. When operating in photovoltaic mode, a noise current density of 10 fA/Hz1/2 is typical at room temperature. When reverse-biased for greater bandwidth, a noise floor of 60fA/Hz1/2 at -5 V is typical. Linear spectral response results from the low series resistance of the photodiodes. The ETX 500T and ETX 1000T series are optimal for the high-speed, differential mode measurements common in precision optical power meters, optical fiber identifiers, and optical loss test sets. The ETX 500T and ETX1000T photodiodes are packaged in hermetically-sealed TO cans.