Abstract: The present disclosure provides optimized configurations for a directionless reconfigurable optical add/drop multiplexer application. The present invention includes an add module with improved optical signal-to-noise through placing amplifiers prior to a multi-cast optical switch. The present invention includes various drop module configurations utilizing distributed gain, channel selective filters, and bi-directional configurations to reduce power consumption and complexity. Additionally, the present invention includes an integrated broadcast and select architecture.

Abstract: The present disclosure provides reconfigurable optical add drop multiplexer (ROADM) node automatic topology discovery systems and methods providing a mapping of optical connections within a mesh optical network that includes tunable lasers and multi-degree ROADM's with colorless/directionless add/drop. The present disclosure may include additional transceiver, receiver, and add/drop filter equipment integrated in or disposed at a ROADM degree. This equipment supports a so-called topology wavelength which is one of a plurality of wavelengths supported by a wavelength division multiplexed (WDM) system that is dedicated and used solely for topology discovery. The topology wavelength may be utilized by the system to detect interconnects between ROADM degrees and between XCVRs/CDMDs. Further, the automated topology discovery may be integrated within a management system and/or control plane.

Abstract: The present invention provides systems and methods for communication system control utilizing corrected forward error correction (FEC) error location identifiers in multi-level modulation scheme systems. The present invention utilizes precise error correction information, available for each FEC block of a particular code (including, but not limited to, block codes and concatenated block codes employing iterative decoding as well as convolutional codes (including turbo codes) and low-density parity-check code (LDPC) class codes) used (e.g., Bose, Ray-Chaudhuri, Hocquenghem (BCH), Reed-Solomon, etc.), as a result of the FEC decoding process to provide feedback to close the loop for control of a demodulator (i.e., receiver). Each error location can be uniquely traced back to a particular sub-rate signal path, with running, post-FEC corrected BER (bit error rate) calculations generated on each sub-rate signal.

Abstract: The technology described herein provides a low-cost three-port reconfigurable optical add-drop multiplexer (ROADM) with an improved edge profile and add/drop flexibility. The technology described herein further provides a tunable spectral filter utilizing two sets of gratings and lenses and a two-axis micro-electro-mechanical system (MEMS) mirror with a selectively shaped cut-out disposed within the middle of the collimated optical path.

Abstract: The present disclosure provides optimized configurations for a directionless reconfigurable optical add/drop multiplexer application. The present invention includes an add module with improved optical signal-to-noise through placing amplifiers prior to a multi-cast optical switch. The present invention includes various drop module configurations utilizing distributed gain, channel selective filters, and bi-directional configurations to reduce power consumption and complexity. Additionally, the present invention includes an integrated broadcast and select architecture.

Abstract: The present invention provides methods and systems for mitigating polarization changes associated with an optical communication signal caused by mechanical disturbances to an optical fiber dispersion compensation module of an optical communication network. The methods include disposing a first damping material between an optical fiber and a housing associated with the optical fiber dispersion compensation module; wherein the first damping material is selected and positioned such that it mitigates relatively fast polarization changes. Optionally, the methods also include disposing a second damping material between the optical fiber and the housing associated with the optical fiber dispersion compensation module; wherein the second damping material is selected and positioned such that it mitigates relatively slow polarization changes. Thus, frequency range specific optical fiber dispersion compensation module mechanical perturbation isolation methods and systems are provided.

Abstract: The present invention provides methods and systems for mitigating polarization changes associated with an optical communication signal caused by mechanical disturbances to an optical fiber dispersion compensation module of an optical communication network. The methods include disposing a first damping material between an optical fiber and a housing associated with the optical fiber dispersion compensation module; wherein the first damping material is selected and positioned such that it mitigates relatively fast polarization changes. Optionally, the methods also include disposing a second damping material between the optical fiber and the housing associated with the optical fiber dispersion compensation module; wherein the second damping material is selected and positioned such that it mitigates relatively slow polarization changes. Thus, frequency range specific optical fiber dispersion compensation module mechanical perturbation isolation methods and systems are provided.

Abstract: The present invention provides a directionless reconfigurable optical add/drop multiplexer (ROADM) system. The present invention provides a scalable all-optical switching element that includes a combination of 1×N wavelength selective switches (WSS), 1×N splitters/combiners, optical amplifiers, and tunable filters to provide a fully non-blocking solution which can be deployed in a scalable manner. The 1×N splitters are configured to split multiples copies of a plurality of drop wavelengths which can be amplified and sent to a tunable filter which selects out a particular wavelength for drop. The 1×N combiners are configured to combine multiple add wavelengths for egress transmission.

Abstract: The present invention provides systems and methods for communication system control utilizing corrected forward error correction (FEC) error location identifiers in multi-level modulation scheme systems. The present invention utilizes precise error correction information, available for each FEC block of a particular code (including, but not limited to, block codes and concatenated block codes employing iterative decoding as well as convolutional codes (including turbo codes) and low-density parity-check code (LDPC) class codes) used (e.g., Bose, Ray-Chaudhuri, Hocquenghem (BCH), Reed-Solomon, etc.), as a result of the FEC decoding process to provide feedback to close the loop for control of a demodulator (i.e., receiver). Each error location can be uniquely traced back to a particular sub-rate signal path, with running, post-FEC corrected BER (bit error rate) calculations generated on each sub-rate signal.

Abstract: Systems and methods for extended reach low differential latency optical networking with optical amplifiers and dispersion compensation modules configured to minimize latency between transmit and receive paths are provided. Additionally, systems and methods are provided for incorporating absolute time references wherein the relative accuracy of clock time between various servers used in various multi-site enterprises is required. The transport systems and methods are used in conjunction with low differential latency systems. The transport systems and methods provide that the differential latency between transmit and receive directions is maintained within about +/?5 microseconds of the transmit/receive path differential delay requirement in order to perform within the overall parameters of the low differential latency system architecture.

Abstract: The technology described herein provides a low-cost three-port reconfigurable optical add-drop multiplexer (ROADM) with an improved edge profile and add/drop flexibility. The technology described herein further provides a tunable spectral filter utilizing two sets of gratings and lenses and a two-axis micro-electro-mechanical system (MEMS) mirror with a selectively shaped cut-out disposed within the middle of the collimated optical path.

Abstract: A universal in-service monitoring scheme to monitor performances of optical networks, including elements that make up the optical network, is proposed. The elements may be a wavelength selective switch or an optical cross connect. In this scheme, a small tunable probe signal is injected into the optical network via an input of the network. An output signal is received at the output and processed to determine if the probe signal is contained within the output signal. The scheme is such that probe signal injection and detection devices need not be physically co-located. Thus, the scheme is useful to test even optical network that spans thousands of miles. The probe signal is non-interfering with the network traffic so the network can be providing service while its performance is monitored. As examples of the probe signal detection mechanisms include lock-in amplification and coherent detection.

Abstract: A flexible wavelength switch fabric may be implemented with multiple groups of reconfigurable blocking filters or with multiple multi-in, single out wavelength selective switches. The behaviors of reconfigurable blocking filters are individually settable, such as channel blocking, channel spacing, transmission rate, and default blocking state. Add and drop taps may be added to provide arbitrary add/drop capability. Optical splitters/combiners used may be tunable so that insertion losses may be minimized for the overall network.

Abstract: Consistent with the present invention, a tunable laser emits a monitoring signal which is combined with the WDM channels typically at the transmit side of a WDM system. At each monitoring point along the WDM system, the WDM channels are filtered out, the monitoring signal is sensed, and desired systems parameters (e.g., gain flatness, dispersion, PMD and OSNR) are measured. Accordingly, a single tunable element, i.e., the tunable laser, can be provided, thereby reducing costs. Moreover, system performance can be ascertained regardless of whether WDM channels are present.

Abstract: An optical waveguide having a refractive index variation is formed by interfering two beams thereon and varying a fringe contrast of the interference pattern. This variation in fringe contrast may be provided by controlling the relative polarizations of the two interfering beams or the relative intensities of the two interfering beams. Preferably, a substantially constant total intensity is provided to the waveguide during the variation in fringe contrast.

Abstract: In accordance with the present invention, optical channels to be demultiplexed are supplied to first and second optical fibers via an optical splitter. Low loss interference filters, for example, coupled to the first and second optical fibers, select respective groups of channels. Each group of channels is next demultiplexed with sub-demultiplexers into individual channels, each of which is then sensed with a corresponding photodetector. Although the optical splitter introduces an optical power loss at the input to the demultiplexer, the interference filters and sub-demultiplexers create little additional loss. As a result, the total power loss associated with the present invention is significantly less than that obtained with a conventional n channel demultiplexer based on a 1×n splitter. Accordingly, large numbers of channels, e.g., in excess of forty can be readily demultiplexed and detected.

Abstract: An optical add/drop multiplexer (OADM) is provided wherein input optical channels are supplied on first and second optical fibers, e.g. via an optical splitter. Low loss interference filters, for example, coupled to the first and second optical fibers, select respective groups or bands of channels. Selected groups of channels to be dropped by the OADM may be demultiplexed with sub-demultiplexers into individual channels. Groups of express channels are supplied to associated filters or gratings to ensure that the channel groups selected from the first and second optical fibers to do not contain undesired channels. Channels to be added by the OADM are multiplexed with sub-multiplexers into channel groups corresponding to the dropped channel groups. The added channel groups and the express channel groups are combined on a single output fiber.

Abstract: A waveguide coupler comprises at least a first waveguide coupled at a coupling region to a second waveguide such that at least a part of radiation propagating along the first waveguide is coupled into the second waveguide. The second waveguide comprises a diffraction grating disposed at the coupling region to inhibit coupling of radiation from the first waveguide into the second waveguide at wavelengths characteristic of the diffraction grating.

Abstract: A dual-band optical filter is disclosed which has two transmission bands. The first band is relatively narrow (about 1 nm) and encompasses a wavelength of about 1550 nm, while the second band is relatively broad (greater than 50 nm) to transmit wavelengths in a range of 1300-1400 nm. Accordingly, the filter can be used in wavelength division multiplexed communication systems to simultaneously select a payload channel having a wavelength of approximately 1550 nm, and a 1310 nm service channel.

Abstract: In accordance with the present invention, optical channels to be demultiplexed are supplied to first and second optical fibers via an optical splitter. Low loss interference filters, for example, coupled to the first and second optical fibers, select respective groups of channels. Each group of channels is next demultiplexed with sub-demultiplexers into individual channels, each of which is then sensed with a corresponding photodetector. Although the optical splitter introduces an optical power loss at the input to the demultiplexer, the interference filters and sub-demultiplexers create little additional loss. As a result, the total power loss associated with the present invention is significantly less than that obtained with a conventional n channel demultiplexer based on a 1×n splitter. Accordingly, large numbers of channels, e.g., in excess of forty can be readily demultiplexed and detected.