We report the first transmission of copolarized 40-Gb/s channels with 0.8-b/s/Hz spectral efficiency. We transmit 25 channels over 1200 km of nonzero-dispersion fiber (1600 km with adjacent channels orthogonally polarized). This result was obtained using differential phase-shift keying, and without forward error correction.

A high-voltage back-illuminated InGaAs photogenerator capable of producing an open-circuit voltage of 4.3 V with 5 /spl mu/W illumination at 1554 nm and 10.3 V with 500 /spl mu/W has been successfully fabricated. Factors contributing to the photogenerator's effectiveness were the large number of diode elements, N=30, a high short-circuit responsivity, r=0.025 A/W, and a low saturation current, I/sub s/=3.95 nA. As a demonstration, the photogenerator was connected to a MEMS optical shutter to build a novel self-powered optical power limiter that might be used to implement autonomous signal power control in optical communication networks. It is expected that the high voltage generated by this device can facilitate the design of a large variety of useful optically powered long-wavelength lightwave circuits.

We report a high-voltage integrated optical-to-electrical power converter, or photogenerator, operating in the long-wavelength (1480-1650 nm) regime for use in fiber-optic networks. These devices deliver power at voltages in excess of 10 V, which is sufficient to operate switches, micromechanical devices, electronic controllers, optoelectronic circuits and other electrical devices. The high-voltage photogenerator enables provisioning and protection at unpowered nodes in fiber-optic networks, using only the long wavelength light present in the optical fiber as the power source. We also demonstrated its use with a MEMS optical shutter to construct a novel optical power limiter.