An Optical Dispersion Compensator (ODC) is disclosed, the ODC being suitable for managing chromatic dispersion of an optical signal for transmission over an optical fiber. The ODC comprises a first ODC unit (202) arranged on a first optical bus (206), a second ODC unit (204) arranged on a second optical bus (208), parallel to the first optical bus (206), and a switching element (210) interconnecting the first and second optical buses (206, 208) between the first and second ODC units (202, 204). The first and second ODC units (202, 204) are operable to provide a delay to the optical signal that varies with frequency. The switching element (210) is configured, in a first state, to switch an optical signal received on one of the first or second optical buses (206, 208) to the other of the first or second optical buses (208, 206) and, in a second state, to maintain an optical signal received on one of the first or second optical buses (206, 208) on the optical bus on which it was received (206, 208). Reflective elements (710) may be included in the ODC, providing bidirectional propagation through one of more ODC units.

An Optical Dispersion Compensator (ODC) is disclosed, the ODC being suitable for managing chromatic dispersion of an optical signal for transmission over an optical fiber. The ODC comprises a first ODC unit (202) arranged on a first optical bus (206), a second ODC unit (204) arranged on a second optical bus (208), parallel to the first optical bus (206), and a switching element (210) interconnecting the first and second optical buses (206, 208) between the first and second ODC units (202, 204). The first and second ODC units (202, 204) are operable to provide a delay to the optical signal that varies with frequency. The switching element (210) is configured, in a first state, to switch an optical signal received on one of the first or second optical buses (206, 208) to the other of the first or second optical buses (208, 206) and, in a second state, to maintain an optical signal received on one of the first or second optical buses (206, 208) on the optical bus on which it was received (206, 208). Reflective elements (710) may be included in the ODC, providing bidirectional propagation through one of more ODC units.

[Object] An object is to provide a dispersion compensating system with a large amount of dispersion compensation and reduced operation costs.

[Solution] As a dispersion compensating system in which a core node 1 and an access node 2 are connected through a ring network 3, the access node 2 includes a delay measurement unit 218 configured to receive delay measurement signals from the core node 1 to measure a delay between the core node 1 and the access node 2, an average dispersion amount calculation unit 219 configured to calculate an amount of dispersion compensation to be applied to an optical burst signal prior to transmission to the ring network 3, based on the delay thus measured, and a real-part inverse dispersion application unit 213I configured to perform pre-equalization on a waveform of the optical burst signal prior to the transmission, based on the calculated amount of dispersion compensation.

[Object] An object is to provide a dispersion compensating system with a large amount of dispersion compensation and reduced operation costs.

[Solution] As a dispersion compensating system in which a core node 1 and an access node 2 are connected through a ring network 3, the access node 2 includes a delay measurement unit 218 configured to receive delay measurement signals from the core node 1 to measure a delay between the core node 1 and the access node 2, an average dispersion amount calculation unit 219 configured to calculate an amount of dispersion compensation to be applied to an optical burst signal prior to transmission to the ring network 3, based on the delay thus measured, and a real-part inverse dispersion application unit 213I configured to perform pre-equalization on a waveform of the optical burst signal prior to the transmission, based on the calculated amount of dispersion compensation.

Methods and systems relating to administration of access credentials for electronic access control are disclosed. Web resources are provided for rendering a webpage including an access credential. A server device receives an access instruction authorizing a user to access an electronic lock associated with the access credential. A client device of the user transmits a first request for the access credential. The first request may be generated by a browser application of the client device. The server device provides the web resources and a browser cookie to the client device. Responsive to subsequent requests for the access credential, the server device determines whether the client device is authorized to receive the access credential based on the client device providing the browser cookie. When the server device determines that a subsequent request authorizes the client device to receive the access credential, the web resources are provided to the browser application.

The present invention is directed to techniques and systems for extension of unrepeatered submarine fiber links to provide an increase in reach of unrepeatered fiber transmission. Both single channel unrepeatered systems and multiple channel unrepeatered systems can be used. The multiple channel unrepeatered systems can further employ nonlinearity compensation. The present invention is also directed to methods of signal transmission using the unrepeatered systems.

A method of characterizing a multimode optical fiber results in a measure of estimated modal bandwidth (EMB) that is independent of the bandwidth of the light used in the characterization. The method includes propagating pulses of light along the multimode optical fiber at prescribed radial positions relative to an optical axis of the multimode optical fiber and detecting output pulses from the multimode optical fiber corresponding to the pulses of light propagated along the multimode optical fiber at the prescribed radial positions relative to the optical axis of the multimode optical fiber. An estimated modal bandwidth of the multimode optical fiber is calculated in a manner that accounts for chromatic dispersion of the multimode optical fiber.

A method of characterizing a multimode optical fiber results in a measure of estimated modal bandwidth (EMB) that is independent of the bandwidth of the light used in the characterization. The method includes propagating pulses of light along the multimode optical fiber at prescribed radial positions relative to an optical axis of the multimode optical fiber and detecting output pulses from the multimode optical fiber corresponding to the pulses of light propagated along the multimode optical fiber at the prescribed radial positions relative to the optical axis of the multimode optical fiber. An estimated modal bandwidth of the multimode optical fiber is calculated in a manner that accounts for chromatic dispersion of the multimode optical fiber.

The present disclosure provides signal management with unequal eye spacing by: determining a dispersion slope of a channel between a transmitter and a receiver based on a temperature of the transmitter and a wavelength used by the transmitter to transmit signals over the channel; determining maximum and minimum powers for transmission over the channel; assigning a plurality of rails to a corresponding plurality of power levels, wherein amplitude differences between adjacent rails of the plurality of rails are based on the dispersion slope and produce a first eye pattern with a first Ratio of Level Mismatch (RLM) less than one; encoding, by the transmitter, data onto a conditioned signal according to the plurality of rails; and transmitting the conditioned signal over the channel, so that the conditioned signal demonstrates a second eye pattern with a second RLM greater than the first RLM when received at the receiver.

The present disclosure provides signal management with unequal eye spacing by: determining a dispersion slope of a channel between a transmitter and a receiver based on a temperature of the transmitter and a wavelength used by the transmitter to transmit signals over the channel; determining maximum and minimum powers for transmission over the channel; assigning a plurality of rails to a corresponding plurality of power levels, wherein amplitude differences between adjacent rails of the plurality of rails are based on the dispersion slope and produce a first eye pattern with a first Ratio of Level Mismatch (RLM) less than one; encoding, by the transmitter, data onto a conditioned signal according to the plurality of rails; and transmitting the conditioned signal over the channel, so that the conditioned signal demonstrates a second eye pattern with a second RLM greater than the first RLM when received at the receiver.