Discovery Semiconductors Inc.'s 700 series balanced photodiodes consist of a push-pull pair of InGaAs photodiodes, each of which can handle optical power of >10 mW. The four models exhibit polarization-dependent loss of 0.05 dB. The DSC710 and DSC720 have typical bandwidths of 10 and 20 GHz, respectively, exhibit responsivity of 0.80 A/W at 1300 nm and 0.75 A/W at 1550 nm, and handle >30 and >20 mW of optical power, respectively. The DSC730 and DSC740 have typical bandwidths of 30 and 40 GHz, respectively, and both exhibit typical responsivity of 0.65 A/W at 1300 nm and 0.60 A/W at 1550 nm. The 730 model handles optical power of >15 mW, and the 740, >10 mW. The 710 and 720 versions will serve the 10-Gb differential phase shift keying (DPSK) and the differential quadrature phase shift keying (DQPSK) markets, and the 730 and 740 are for 40-Gb DPSK and DQPSK applications.