Abstract: An apparatus for and a method of direct MAC-to-MAC transmission over an optical ring network employing WDM or DWDM. In a first embodiment, the connections to the transmit and receive portions of two MAC devices in the node are crossed such that the transmitter and receiver of a MAC are not connected to the same optical add/drop multiplexer (OADM). The drop and add module of the OADM are connected in tandem on the same optical ring. A second OADM is similarly configured and located on the opposite optical ring. The receive and transmit portions of a MAC device are split across two OADMs wherein the receiver is connected to the drop module of one OADM and the transmitter is connected to the add module of the other OADM. In a second embodiment, the drop and add modules of each OADM are connected to opposite rings, i.e. the drop module is connected to an optical ring carrying traffic in one direction while the add module is connected to an optical ring carrying traffic flowing in the opposite direction.

Abstract: An optical network terminator for terminating and reducing the accumulated noise in optical networks, particularly ring based networks. The terminator eliminates problems of noise accumulation from amplifier spontaneous emission (ASE), thermal noise, etc., while providing bi-directional communications in the optical network. The optical network may have any topology including ring, star, mesh, point-to-point, etc. In the case of an optical ring, the ring is broken and an optical terminator is placed in line therewith. The optical network terminator includes a filer such as an optical demultiplexer/multiplexer or Fiber Bragg Grating (FBG) based filter. Each individual wavelength of light is filtered and a multi-wavelength optical output is generated whereby the noise accumulation is removed. Each channel is adapted to only pass a band-limited signal around the center frequency corresponding to the wavelengths supported by the particular optical ring network.

Abstract: A connection mechanism permitting a unidirectional processing device to function as a virtual bi-directional processing device. A pass through dummy connection is inserted in a unidirectional circuit card to permit the connection of standard keyed duplex-paired cables to other processing cards. The use of keyed cables to connect the various circuit cards in a system reduces the burden of a user to manually insure that all cables are properly connected between cards. The pass through dummy connection may be any suitable media such as optical fiber for optical signals or electrical cable, wire or printed circuit board traces for electrical signal.

Abstract: A light-modulating cell for providing a desired propagation of light impinging thereon is presented. The cell comprises at least two substrates, made a material substantially optically transparent with respect to incident radiation of a desired wavelength range, and at least one reservoir attached to at least one of the substrates. These at least two substrates define a plurality of spaced-apart outer surfaces and a sealed therebetween, respectively. The space is filled with a first, substantially liquid light-modulating medium, while the reservoir contains predetermined amount of a second, substantially liquid light-modulating medium. The inside of the reservoir is connected to the inside of the sealed space for providing a continuous flow of the first and second media into and out of the space.