Optical coherent receivers for 2.5 and 10 Gb/s

We present coherent optical detection of 2.5 Gb/s and 10 Gb/s with high sensitivity for fiber-optic and free-space applications. The system can operate at 840 nm, 1064 nm, 1310 nm, and in the S, L and C bands. We show the detection of conventional on/off keying (OOK) as well as differential phase-shift keying (DPSK).