Abstract: The invention includes methods and apparatuses to adjust an optical signal transmitted through an optical amplifier, such as in a wavelength division multiplexed optical network. The methods and apparatus of the invention calculate polarization effects which cause degradation to the optical signal. A measurement of the polarization-related degradation of an optical signal is calculated by using at least one reference signal. In some embodiments of the invention, the reference signal is depolarized or has scrambled polarizations. The invention is typically used in long-haul optical networks.

Abstract: A system and method for simultaneous delivery of a plurality of independent blocks of 500 MHz digital broadcast television services, stacking a plurality of RF blocks on a plurality of spectrally sliced WDM optical bands.

Abstract: The present invention provides methods and apparatuses for controlling a gain of an optical fiber amplifier. Gain circuitry operates in an opened loop configuration and uses a predetermined function relating a power variation of at least one wavelength region with a pump power adjustment for at least one optical pump. Two approximate linear relationships between the input signal power variations and the required pump power adjustments are utilized in controlling the Raman fiber amplifier. Each approximate linear relationship includes at least one linear coefficient that relates a power variation for a specific wavelength region and a power adjustment of a specific Raman pump. The dynamic gain control technique is applicable to an Erbium-doped fiber/waveguide amplifier. Also, a dynamic gain control technique controls a backward-pumped Raman amplifier, in which the power variation is determined at one geographical location and the optical pumps are controlled at another geographical location.

Abstract: A method for cost-effective optical transmission with fast Raman tilt or other transient event control uses a combination of Erbium-doped fiber amplifiers (EDFAs) and Raman fiber amplifiers (RFAs), where EDFAs are used as the primary optical amplifiers to compensate the span loss while the RFA (advantageously a forward-pumped RFA) is used only in some specific spans with a feed-forward control circuit serving as a fast Raman tilt transient compensator, the RFA also serving as an optical amplifier. A long haul optical transmission system using feed-forward controlled RFA's periodically spaced along its length, for example, when add-drop multiplexing is used, makes full use of the economics of EDFAs and the fast tilt transient control capability of a RFA enabled by an adjustable speed feed-forward or feed-back control technique.

Abstract: A network arrangement where traffic elements of network nodes are programmable. A traffic element comprises electrically controllable transceiver pool having one or more ports that are coupled to an electrically controllable optical director that has all-optical information communication paths. The transceiver pool has one or more customer connection points in addition to the one or more connection points that connect to the optical director, and is adapted to couple a signal from any of the customer connection points to the optical director, at a particular wavelength. The choices for the specific coupling within the optical director and of the wavelengths are specified by control signals that are applied to the transceiver pool and to the optical director.

Abstract: The present invention provides methods and apparatuses for controlling a gain of an optical fiber amplifier. Gain circuitry operates in an opened loop configuration and uses a predetermined function relating a power variation of at least one wavelength region with a pump power adjustment for at least one optical pump. Two approximate linear relationships between the input signal power variations and the required pump power adjustments are utilized in controlling the Raman fiber amplifier. Each approximate linear relationship includes at least one linear coefficient that relates a power variation for a specific wavelength region and a power adjustment of a specific Raman pump. The dynamic gain control technique is applicable to an Erbium-doped fiber/waveguide amplifier. Also, a dynamic gain control technique controls a backward-pumped Raman amplifier, in which the power variation is determined at one geographical location and the optical pumps are controlled at another geographical location.

Abstract: The present invention provides methods and apparatuses for controlling a gain of an optical fiber amplifier. Gain circuitry operates in an opened loop configuration and uses a predetermined function relating a power variation of at least one wavelength region with a pump power adjustment for at least one optical pump. Two approximate linear relationships between the input signal power variations and the required pump power adjustments are utilized in controlling the Raman fiber amplifier. Each approximate linear relationship includes at least one linear coefficient that relates a power variation for a specific wavelength region and a power adjustment of a specific Raman pump. The dynamic gain control technique is applicable to an Erbium-doped fiber/waveguide amplifier. Also, a dynamic gain control technique controls a backward-pumped Raman amplifier, in which the power variation is determined at one geographical location and the optical pumps are controlled at another geographical location.

Abstract: An arrangement provides low cost path protection in an optical communications network. The arrangement has a portion 3 that provides (broadcasts) an outbound optical signal, and at least first and second transmitting portions 202, 206 transmit the outbound optical signal simultaneously onto at least first and second respective mutually distinct optical pathways 231, 232. Meanwhile, a selection arrangement 204 selects among plural incoming optical signals (via 1, 5) according to a SELECT control signal 228 to provide a selected signal, and an analyzer 222 analyzes characteristics of the selected signal to provide the SELECT control signal 228.

Abstract: An optical network for providing a plurality of end users with video content, which includes a plurality of video head ends, each coupled to a pair of video hub offices via a plurality of diverse optical communication paths, where each hub office is coupled to a plurality of video serving offices via a pair of optical fibers arranged in a ring structure to provide a working link and a protection link, each video serving office adapted and arranged for distributing video content to a plurality of end users.

Abstract: A system and method for simultaneous delivery of a plurality of independent blocks of 500 MHz digital broadcast television services, stacking a plurality of RF blocks on a plurality of spectrally sliced WDM optical bands.

Abstract: A method for cost-effective optical transmission with fast Raman tilt or other transient event control uses a combination of Erbium-doped fiber amplifiers (EDFAs) and Raman fiber amplifiers (RFAs), where EDFAs are used as the primary optical amplifiers to compensate the span loss while the RFA (advantageously a forward-pumped RFA) is used only in some specific spans with a feed-forward control circuit serving as a fast Raman tilt transient compensator, the RFA also serving as an optical amplifier. A long haul optical transmission system using feed-forward controlled RFA's periodically spaced along its length, for example, when add-drop multiplexing is used, makes full use of the economics of EDFAs and the fast tilt transient control capability of a RFA enabled by an adjustable speed feed-forward or feed-back control technique.

Abstract: The present invention provides methods and apparatuses for controlling a gain of a bidirectionally-pumped Raman fiber amplifier having both forward optical pumps and backward optical pumps. The overall gain is controlled by adjusting the forward optical pumps, while the power levels of the backward optical pumps are essentially fixed. Gain circuitry operates in an opened loop configuration and uses a predetermined function relating a power variation of at least one wavelength region with a pump power adjustment for at least one forward optical pump. Two approximate linear relationships between the input signal power variations and the required pump power adjustments are utilized in controlling the Raman fiber amplifier. Each approximate linear relationship includes at least one linear coefficient that relates a power variation for a specific wavelength region and a power adjustment of a specific Raman pump.

Abstract: The present invention provides methods and apparatuses for controlling a gain of a bidirectionally-pumped Raman fiber amplifier having both forward optical pumps and backward optical pumps. The overall gain is controlled by adjusting the forward optical pumps, while the power levels of the backward optical pumps are essentially fixed. Gain circuitry operates in an opened loop configuration and uses a predetermined function relating a power variation of at least one wavelength region with a pump power adjustment for at least one forward optical pump. Two approximate linear relationships between the input signal power variations and the required pump power adjustments are utilized in controlling the Raman fiber amplifier. Each approximate linear relationship includes at least one linear coefficient that relates a power variation for a specific wavelength region and a power adjustment of a specific Raman pump.

Abstract: In an optical transmission link having discrete optical reflection sources that cause multi path interference (MPI) and optical return loss (ORL), a method determines how to reduce to beneath a predetermined threshold, a predetermined phenomenon (MPI or ORL or a composite of the two). The method involves (408/428/458) measuring link parameters of the optical transmission link using an optical reflectometry technique, (410/430/460) calculating a level of the predetermined phenomenon based on the link parameters, and (416/436/466) simulating replacement of a number of the reflection sources until the calculated level of the predetermined phenomenon is reduced to less than the predetermined threshold. The method may be performed within a portable optical reflectometry device to facilitate field simulations.

Abstract: Methods and systems for analyzing optical parameters of a selected optical fiber member are disclosed. A signal input from an optical fiber member may be selected by instructing a corresponding optical separation device. The output from the corresponding optical separation device may be combined with the outputs of other optical separation devices using an optical coupler. A measurement circuit may measure the optical parameter from the output. Proper operation of an optical separation device may be validated by a monitoring circuit. The monitoring circuit may provide an indication to a user or may be processed by a diagnostic processor. A processing circuit may select one of the optical separation devices in order to measure the optical parameter for a corresponding optical fiber member and consequently may instruct an adjustment circuit to cause the selected optical fiber member to conform to a desired value of the optical parameter.

Abstract: An arrangement provides low cost path protection in an optical communications network. The arrangement has a portion 3 that provides (broadcasts) an outbound optical signal, and at least first and second transmitting portions 202, 206 transmit the outbound optical signal simultaneously onto at least first and second respective mutually distinct optical pathways 231, 232. Meanwhile, a selection arrangement 204 selects among plural incoming optical signals (via 1, 5) according to a SELECT control signal 228 to provide a selected signal, and an analyzer 222 analyzes characteristics of the selected signal to provide the SELECT control signal 228.

Abstract: The present invention provides methods and apparatuses for analyzing optical parameters of a selected optical fiber member. A signal input from an optical fiber member is selected by instructing a corresponding optical separation device. The output from the corresponding optical separation device is combined with the outputs of other optical separation devices using an optical coupler. A common measurement circuit measures the optical parameter from the output. Proper operation of an optical separation device is validated by a monitoring circuit. The monitoring circuit may provide an indication to a user or may be processed by a diagnostic processor. A processing circuit selects one of the optical separation devices in order to measure the optical parameter for a corresponding optical fiber member and consequently instructs an adjustment circuit to cause the selected optical fiber member to conform to a desired value of the optical parameter.

Abstract: The present invention provides methods and apparatuses for controlling a gain of an optical fiber amplifier. Gain circuitry operates in an opened loop configuration and uses a predetermined function relating a power variation of at least one wavelength region with a pump power adjustment for at least one optical pump. Two approximate linear relationships between the input signal power variations and the required pump power adjustments are utilized in controlling the Raman fiber amplifier. Each approximate linear relationship includes at least one linear coefficient that relates a power variation for a specific wavelength region and a power adjustment of a specific Raman pump. The dynamic gain control technique is applicable to an Erbium-doped fiber/waveguide amplifier. Also, a dynamic gain control technique controls a backward-pumped Raman amplifier, in which the power variation is determined at one geographical location and the optical pumps are controlled at another geographical location.

Abstract: A method for cost-effective optical transmission with fast Raman tilt or other transient event control uses a combination of Erbium-doped fiber amplifiers (EDFAs) and Raman fiber amplifiers (RFAs), where EDFAs are used as the primary optical amplifiers to compensate the span loss while the RFA (advantageously a forward-pumped RFA) is used only in some specific spans with a feed-forward control circuit serving as a fast Raman tilt transient compensator, the RFA also serving as an optical amplifier. A long haul optical transmission system using feed-forward controlled RFA's periodically spaced along its length, for example, when add-drop multiplexing is used, makes full use of the economics of EDFAs and the fast tilt transient control capability of a RFA enabled by an adjustable speed feed-forward or feed-back control technique.

Abstract: A method for cost-effective optical transmission with fast Raman tilt or other transient event control uses a combination of Erbium-doped fiber amplifiers (EDFAs) and Raman fiber amplifiers (RFAs), where EDFAs are used as the primary optical amplifiers to compensate the span loss while the RFA (advantageously a forward-pumped RFA) is used only in some specific spans with a feed-forward control circuit serving as a fast Raman tilt transient compensator, the RFA also serving as an optical amplifier. A long haul optical transmission system using feed-forward controlled RFA's periodically spaced along its length, for example, when add-drop multiplexing is used, makes full use of the economics of EDFAs and the fast tilt transient control capability of a RFA enabled by an adjustable speed feed-forward or feed-back control technique.