Abstract: A closed-ring transparent optical communication network that provides for protection of the principal communication channel of each supported wavelength and supports occasional traffic on a separate channel. In the case of a breakdown of or degradation in the principal channel, these communications are redirected to the occasional channel.

Abstract: An optical transmission bypass device attaching a network device to a fiber optic network allows fiber optic transmissions to bypass the network device when not powered, thereby maintaining continuity of the fiber network. A first and second actuating optical reflector has a reflective face that, in an un-powered state, is disposed to place the reflective face of the actuating optical reflector in a first position with respect to an optical path of an optical port, and, in a powered state, is disposed to place the reflective face of the actuating optical reflector in a second position with respect to the optical path of the optical port.

Abstract: Communicating a signal includes receiving the signal at a primary device of a switching system, where the primary device is associated with a primary path along which the signal is propagating. A primary overmodulation signal associated with the primary path is generated. The absence of the primary overmodulation signal is detected, and an operating signal is sent from the primary device to a secondary device of the switching system, where the secondary device is associated with a secondary path. The operating signal operates to initiate propagation of the signal along the secondary path.

Abstract: An optical communication system and method for starting up and shutting down the system to ensure safety during repair of a fiber break are disclosed. A technique for shutting down an optical communication system having spans of optical transmission fiber interspersed serially between optical transformation sites and a plurality of amplifier sites includes shutting down both amplifiers on either side of a fiber disruption and both amplifiers in the same amplifier sites serving transmission in an opposite direction, followed by deactivation of all amplifiers within the same optical line between optical transformation sites. During startup, amplifiers enter an operating mode to ignore a system shutdown signal, an amplifier at a terminal site is forced on, and then successive amplifiers step through an intermediate safe power level before reaching full operating power.

Abstract: Each piece of WDM light transmitted via the first and second line is demultiplexed for each wavelength by the first and second optical demultiplexer, and is selected by n optical selectors. Each selected optical signal is split by n optical splitters and is input to one set of optical switches. Each one of optical signals from the set of optical switches is selected by n optical selectors. Furthermore, each selected optical signal is regenerated by n wavelength converters. Each regenerated optical signal is split by n optical splitters, and is multiplexed by the first and second optical multiplexers.

Abstract: Disclosed are the multiplex communication system and the method therefore. A fault detection part of a duplex switching device detects it as generation of fault when recognizable signals are not detected from a connected line within a prescribed time. When the fault detection part detects the generation of fault in the present system line, the line switching part switches the lines from the present line to the standby line to perform communication between a terminal device and another terminal device therethrough. Also, the fault detection part notifies the generation of fault to the other duplex switching device after a prescribed switching protection time has passed from the time of the fault detected by the fault detection part, so the selection of the lines becomes consistent.

Abstract: The present invention is directed to a protection switch for use in a node of a two-fiber optical shared protection ring. The two-fiber optical shared protection ring propagates at least one bi-directional channel. Each bi-directional channel includes a working first wavelength signal and a working second wavelength signal. One fiber in the two-fiber optical channel shared protection ring propagates the working first wavelength signal in a first direction and the other fiber in the two-fiber optical channel shared protection ring propagating the working second wavelength signal in a second direction opposite the first direction. The switch includes an N×N optical switch fabric system disposed in the node. The N×N optical switch fabric includes 2N input/output (I/O) ports, wherein N is four, or an integer multiple of four. Each optical switch fabric is configured to switch at least one bi-directional channel. At least N three-port optical devices are coupled to N of the I/O ports.

Abstract: The present invention is a method to protect a cross-connect OXC/OEXC used to forward at least one signal AB from a main input IN to a main output OUT. Said method comprises the following step: dividing the at least one signal AB into two substantially identical signal parts, a first signal part A and a corresponding signal part B; routing the at least one first signal part A through a first cross-connect OXC1/OEXC1, from the input IN to the output OUT; detection of a failure affecting the at least one first signal part A; interruption of the routing path for the at least one first signal part A; routing the at least one corresponding signal part B through a second cross-connect OXC2/OEXC2, from the input IN to the output (OUT).