Abstract: A high-speed access data network in which upstream and downstream traffic is logically or physically separated. The network can use the Ethernet media access control (MAC) layer protocol over distances that are much larger than conventionally possible with the Ethernet MAC layer protocol. In a configuration including a central office and multiple subscribers, the central office is removed from the collision domain, which can be made relatively small, without limiting the distance between the central office and the subscribers. The downstream data rate is not limited by the size of the collision domain and can thus be made almost arbitrarily large. Furthermore, by allowing a smaller collision domain, greater upstream data rates can be used. It is thus possible to use ubiquitous and inexpensive Ethernet LAN technology in highly cost-sensitive applications such as residential broadband access.

Abstract: An arrangement for butt coupling of waveguide electrooptic plates to form a crossbar switch. The arrangement includes a stack of M splitter plates, each of which routes an injected optical signal to one of N outputs, and a stack of N combiner plates, each of which routes the signal of a selected one of M inputs to a common output. The stack of splitter plates is rotated with respect to the stack of combiner plates and the output signal ports of the splitter plates are coupled to the input signal ports of the combiner plates, so that each output of an splitter plate is connected to a different combiner plate. Within each splitter plate there is a fan-out network of waveguide electrooptic couplers and each coupler, under electric control, routes signals from one input to either one of two outputs. With j levels of such interconnected couplers 2.sup.j output are developed. The combiner plates have an identical architecture but with a signal flow in the reverse direction.

Abstract: A star coupler for a single-mode-fiber optical local area network which reduces the amount of fiber required by a factor of two and diminishes the number of components by one-half. This savings in fiber and components is effected by "reflecting" signals which appear at various locations of the network back toward the input ports. The arrangement forms a broadcast-type of local area network where a message transmitted by any user can be received by all users.

Abstract: An optical pulse equalization technique for minimizing pulse dispersion in a single-mode fiber transmission system where there is a mismatch between the optical source (1) wavelength and the wavelength at which a transmission single-mode fiber (2) has a zero total dispersion utilizes the positive and negative dispersion characteristics of single-mode fibers on both sides of the zero total dispersion wavelength. A second equalizer single-mode fiber (3) is used as an optical equalizer. This equalizer single-mode fiber has the property that the optical source wavelength lies at a value which is between the zero dispersion wavelengths of the transmission and equalizer single-mode fibers. The transmission fiber and the equalizer fiber have different dispersion signs at the source wavelength and the length of the equalizer fiber is chosen to be equal to the length of transmission fiber times the ratio of the dispersions for the fibers at the source wavelength.