A 1 W Linear High-Power InP Balanced Uni-Traveling Carrier Photodetector

IGH-power handling photo-detectors with large bandwidths and high linearity have become critical components for analog links with high dynamic range as well as digital coherent optical links using advanced modulation formats with high LO powers [1,2]. A large spurious-free dynamic range is required for these applications to enhance the signal-to-noise ratio with minimal non-linear intermodulation products, requiring photodiodes with very high photocurrent level handling capability to maximize electrical output power with high linearity [3]. One way to increase RF output power is by integrating RF power combiners with multiple single-junction photodiodes on the same chip [4]. However, insertion losses of on-chip Wilkinson power combiners on InP substrates limits net RF output power gain. Recently, a balanced photo-detector approach has demonstrated increased RF output power [5,6,7]. Back-illuminated balanced photo-detectors where demonstrated with a saturation current of 136 mA (1-dB compression point) per diode and 160 mW RF power out at 11 GHz and 10oC for single device illumination by a lensed-fiber [6]. In this work we report on an integrated high-power balanced uni-traveling carrier (UTC) photodiode pair, measured on wafer using a single-mode fiber (SMF) array to Manuscript received April 6, 2011. This work is support in part by DARPA under AFRL contract No. FA8650-10-C-7003 supervised by Drs. S. Rodgers, V. Kovanis, D. Stevens and R. Esman. Vincent Houtsma, T. Hu, N. G. Weimann, R.