Systems and methods are disclosed herein for coherently modulating and demodulating coherent optical signals using 5-bit constellations. The 5-bit constellations have improved suitability for short reach optical communications systems. A first 5-bit constellation can be formed from four rings. The first and fourth rings can form quadrature phase-shift keyed four-symbol sub-constellations, and the second and third rings can form phase-shift keyed twelve symbol constellations. Symbols from the third and fourth sub-constellations are arranged to form a square. A second 5-bit constellation can include an inner 16 symbol sub-constellation and an sixteen symbol outer sub-constellation. Each of the symbols of the inner sub-constellation are equally spaced from its nearest neighboring symbols along both the quadrature and in-phase axes. Each of the symbols in the outer constellation has an equal euclidean-distance with its nearest neighboring symbols in the outer sub-constellation.

A counter-directional optical network having multiple channels includes a source module connected with at least two network nodes by a fiber ribbon including an array of optical fibers. Each channel includes at least one optical fiber. The source module includes multiple signal sources, each signal source connected with one of the channels and operable to transmit a source signal in a direction in the channel. Each network node includes a modulator for processing the source signal with a data input signal forming a message signal, a switch for selecting one of the channels to transmit the message signal and a receiver connected with one of the channels for receiving a message signal from another node. The message signal is transmitted to the receiver of a receiving node in a direction opposite to the transmission direction of the source signal via the channel connected to the receiver of the receiving node.

A counter-directional optical network having multiple channels includes a source module connected with at least two network nodes by a fiber ribbon including an array of optical fibers. Each channel includes at least one optical fiber. The source module includes multiple signal sources, each signal source connected with one of the channels and operable to transmit a source signal in a direction in the channel. Each network node includes a modulator for processing the source signal with a data input signal forming a message signal, a switch for selecting one of the channels to transmit the message signal and a receiver connected with one of the channels for receiving a message signal from another node. The message signal is transmitted to the receiver of a receiving node in a direction opposite to the transmission direction of the source signal via the channel connected to the receiver of the receiving node.

Systems and methods are disclosed herein for coherently modulating and demodulating coherent optical signals using 5-bit constellations. The 5-bit constellations have improved suitability for short reach optical communications systems. A first 5-bit constellation can be formed from four rings. The first and fourth rings can form quadrature phase-shift keyed four-symbol sub-constellations, and the second and third rings can form phase-shift keyed twelve symbol constellations. Symbols from the third and fourth sub-constellations are arranged to form a square. A second 5-bit constellation can include an inner 16 symbol sub-constellation and an sixteen symbol outer sub-constellation. Each of the symbols of the inner sub-constellation are equally spaced from its nearest neighboring symbols along both the quadrature and in-phase axes. Each of the symbols in the outer constellation has an equal euclidean-distance with its nearest neighboring symbols in the outer sub-constellation.

Systems and methods are disclosed herein for coherently modulating and demodulating coherent optical signals using 5-bit constellations. The 5-bit constellations have improved suitability for short reach optical communications systems. A first 5-bit constellation can be formed from four rings. The first and fourth rings can form quadrature phase-shift keyed four-symbol sub-constellations, and the second and third rings can form phase-shift keyed twelve symbol constellations. Symbols from the third and fourth sub-constellations are arranged to form a square. A second 5-bit constellation can include an inner 16 symbol sub-constellation and an sixteen symbol outer sub-constellation. Each of the symbols of the inner sub-constellation are equally spaced from its nearest neighboring symbols along both the quadrature and in-phase axes. Each of the symbols in the outer constellation has an equal euclidean-distance with its nearest neighboring symbols in the outer sub-constellation.

A real-time editing system includes: a control device configured to create a rendering job containing a decode command to a decoder and a render command to a renderer; the renderer configured to create and transmit a decode job to the decoder, based on the rendering job, and render a material video decoded by the decoder; and the decoder configured to decode a compressed material image based on the decode job, and transmit the material image to the renderer.

A real-time editing system includes: a control device configured to create a rendering job containing a decode command to a decoder and a render command to a renderer; the renderer configured to create and transmit a decode job to the decoder, based on the rendering job, and render a material video decoded by the decoder; and the decoder configured to decode a compressed material image based on the decode job, and transmit the material image to the renderer.

Broadband subscriber switchover may be provided. First, a first gateway device may receive a first failure message from a first ring device. The first gateway device may be designated as an access fault detection agent among a plurality of gateway devices. Next, the first gateway device may receive a second failure message from a second ring device. The second failure message may be received via a second gateway device. The first ring device and the second ring device may be in an open-ring. Then the first gateway device may determine that the first ring device has been cut off from the second gateway device based upon the first failure message and the second failure message. The second gateway device may be a master device for the first ring device. The master device for the first ring device may then be switched from the second gateway device to the first gateway device.

Broadband subscriber switchover may be provided. First, a first gateway device may receive a first failure message from a first ring device. The first gateway device may be designated as an access fault detection agent among a plurality of gateway devices. Next, the first gateway device may receive a second failure message from a second ring device. The second failure message may be received via a second gateway device. The first ring device and the second ring device may be in an open-ring. Then the first gateway device may determine that the first ring device has been cut off from the second gateway device based upon the first failure message and the second failure message. The second gateway device may be a master device for the first ring device. The master device for the first ring device may then be switched from the second gateway device to the first gateway device.

In order to enable more stable monitoring of communication status, a communication device is provided with: a setting unit which sets a first wavelength selected from wavelength selection alternatives included in wavelengths of light included in dummy light, and a first transmission power which is selected in accordance with a first communication status from a plurality of transmission power selection alternatives that are set in advance; a generation unit which generates light of the first wavelength from the dummy light; an adjustment unit which adjusts the light of the first wavelength to first light of the first transmission power; and a multiplexing unit which multiplexes the first light with communication light serving as light for a predetermined communication so as not to overlap each other on the time axis, and which delivers the multiplexed light to another communication device.