Ciena Corporation

Vipul Bhatnagar

Michael Y Frankel

Balakrishnan Sridhar

Choudhury A Al Sayeed

David Casson Bownass

Michael George Taylor

Jun Bao

Paul Chedore

Harshad P Sardesai

Charles Haggans

Mahir A Nayfeh

Kevan Peter Jones

Michael J Ransford

Jeffrey C Livas

Minh T Nguyen

Marco Gaudet

Scott Kohlert

Dave C Bownass

Ross Caird

Bruno Doyle

Prasad Dasika

Sridhar Balakrishnan

Giuseppe Bordogna

Darren Hennigar

Jean Luc Archambault

Francois Maurice Rheal Charron

A method of implementing a stretched single optical communication span includes receiving one or more optical signals from an optical fiber span having high loss; adding a pilot signal to the one or more optical signals, subsequent to the receiving; and amplifying the one or more optical signals and the pilot signal with a pre-amplifier that is an Erbium Doped Fiber Amplifier (EDFA). Advantageously, the stretched single span operates below a Hazard 1M environment. A node in a stretched single optical communication span includes an optical multiplexer connected to an optical fiber span having high and a pilot signal, and configured to output a combination of one or more optical signals from the optical fiber span and the pilot signal; and a pre-amplifier that is an EDFA configured to receive the output of the optical multiplexer and provide amplification of the one or more optical signals and the pilot signal.

Stretched single optical span communications system and method avoiding hazardous power levels

Systems and methods for strategizing the insertion and/or removal of a node into and/or out of a network are provided. A system, according to one implementation, includes a processing device and a memory device configured to store a computer program. The computer program includes instructions that, when executed, enable the processing device to configure a Network Element (NE) in a pass-through mode whereby channels are neither added nor dropped to thereby prepare the NE for insertion into or removal from a photonic network. Upon the insertion of the NE into the photonic network or the removal of the NE from the photonic network, the instructions may further enable the processing device to perform a zero configuration procedure for automatically establishing communication along one or more Optical Service Channels (OSCs) and for automatically controlling gain and loss characteristics along one or more fiber links altered by the insertion or removal.

Rapid node insertion into or removal from a photonic network

An Optical Protection Switch (OPS) includes a splitter connected to a transmitted input and a path continuity monitor transmitter and configured to output the transmitted input with a path continuity monitor signal to two paths; a switch connected to a receiver output and configured to provide one of two receiver inputs each from one of the two paths based on a setting of the switch; and one or more path continuity monitor receivers connected to the two receiver inputs and configured to detect a corresponding path continuity monitor signal from a complementary OPS, wherein the setting of the switch is set based upon the received path continuity monitor signals. The one or more path continuity monitor receivers each have a narrow optical bandwidth relative to an overall optical bandwidth of the transmitted input.

Optical switch with path continuity monitoring for optical protection switching

A network element includes a transmitting amplifier configured to transmit to a first optical fiber, wherein the transmitting amplifier has a pump laser; and an optical monitor connected to a second optical fiber and configured to detect a portion of optical power thereon; wherein the pump laser is modulated to convey a signal to a second optical monitor in a second network element connected to the first optical fiber, when the transmitting amplifier is one of in a safety mode and has no input.

Optical amplifier signaling systems and methods for shutoff coordination and topology discovery

Systems and methods describe synchronizing optical protection switching with an Optical Protection Switch (OPS) including a splitter on a transmit side to both a first fiber path and a second fiber path and a receive switch and monitoring port on a receive side with the receive switch set to only one of the first fiber path and the second fiber path. A method includes, responsive to detection of a fault on the first fiber path, generating a link Forward Defect Indication (FDI) and transmitting the link FDI over a messaging channel downstream; and utilizing the link FDI to generate an Optical Protection Switch Indicator (OPSI) status used by the OPS to cause a switch of the receive switch to the second fiber path.

Synchronization of optical protection switching and loading of path specific characteristics

Systems and methods to detect a wavelength of interest (&#x3bb;) amongst one or more wavelengths (&#x3bb;, &#x3bb;, . . . , &#x3bb;) include receiving the one or more wavelengths (&#x3bb;, &#x3bb;, . . . , &#x3bb;); using a portion of a transmitted wavelength (&#x3bb;) as a Local Oscillator (LO) signal to perform performing coherent detection with the one or more wavelengths, wherein the transmitted wavelength (&#x3bb;) and the wavelength of interest (&#x3bb;) are a bi-directional communication link; and determining a presence of the wavelength of interest (&#x3bb;) based on the coherent detection.

Signal detection systems and methods on a fiber carrying multiple wavelengths

A method of adding a transceiver including a transmitter and a receiver to an optical network. The transceiver is controlled to enable the receiver while maintaining the transmitter in a disabled state. The receiver detects a presence of an optical signal at a first wavelength. If an optical signal at the first wavelength is not present, the transmitter is enabled. Responsive to detection that an optical signal at the first wavelength is present: a feature of the optical signal, and a match condition between the detected feature and a predetermined feature are detected. The transmitter is enabled responsive to detection of the match condition.

Method for detecting wavelength usage conflicts in an optical network

The present invention provides a wavelength-switched reconfigurable optical add-drop multiplexer (R-OADM) with wavelength broadcasting capability, such that asymmetric video signal distribution and the like can be performed without sacrificing with respect to component complexity and expense. The present invention utilizes an optical splitting and combining device with the wavelength-switched R-OADM to allow the R-OADM to support network-wide wavelength broadcasts without requiring external regeneration and extra optical transceiver equipment.

Wavelength-switched optical add-drop multiplexer with wavelength broadcasting capability

A bidirectional communication system is disclosed. A single optical line amplifier is used to amplify signals in both the east and west directions. Additionally, a single dispersion compensation module is used to compensate for fiber dispersion in both directions. Using a single optical line amplifier and a single dispersion compensation module for both directions allows for reduction in the number of optical line amplifiers used in a given network.

Bidirectional communication system

System and methods for upgrading an optical add-drop multiplexer (OADM) to higher degree wavelength selective router (WSR)/wavelength selective switch (WSS) are disclosed. For example, an OADM of degree-2 may be provisioned for upgrades to degree-3 and higher. The existing links power and signal-to-noise (SNR) budgets are not significantly affected when the node is upgraded to a higher degree WSS/WSR. Cascaded power dividers and combiners may be used in conjunction with optical amplifiers and reconfigurable blocking filters to increase the number of paths over which an optical signal can be routed/switched without affecting the paths already utilized. Prior to enabling service on either an input or output fiber, taps and combiners are pre-provisioned so as to ensure that at least one additional transmission path is always available.

Method and apparatus for in-service upgrading of OADM to wavelength selective switch of higher degree

An optical communication device, and related method, are provided for reducing ripple in WDM systems. In particular, the optical communication device includes a dynamic gain equalization (DGE) circuit is coupled to an optical communication path carrying the WDM optical signals. The DGE circuit adjusts the powers associated with each channel on a channel-by-channel basis so that the WDM optical signal has a desired power spectrum. The DGE is controlled in response to sense signals generated by an optical performance monitoring (OPM) circuit located downstream from the DGE or substantially co-located with the DGE. The OPM monitors the WDM spectrum for optical signal power variations and outputs the sense signal when the variations fall outside a given tolerance. Typically, one DGE is associated with a group of concatenated amplifiers so that multiple DGEs are provided in a system having many groups of such amplifiers. Likewise, multiple OPMs are provided in such systems, each corresponding to a respective DGE, so that ripple can be reduced and desired WDM optical signal powers can be achieved in the WDM system.

Optical communication system having dynamic gain equalization

A method and apparatus for assigning channel bands to a wavelength division multiplexed (WDM) system is disclosed. The WDM system includes an arrangement of optical amplifiers, banded optical add-drop multiplexers (OADMs) having blocking filters, and a tunable edge filter. The channel band assignment method suppresses amplified stimulated emissions (ASE) in a partially populated system in which at least one of the blocking filters is not in the transmission path. Channel bands are assigned from one edge of an amplified transmission window to the other in a sequential order and the tunable edge filter is adjusted to attenuate ASE wavelengths not blocked by the blocking filters as channels are assigned. A channel decommissioning method is also disclosed which employs similar techniques and the tunable edge filter to suppress ASE as blocking filters are removed or otherwise deselected from the transmission path.

Method and system for suppressing ASE on a WDM network

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.

Use of tunable laser for optical performance monitoring in WDM system

A service channel modem is adapted to determine optical properties of an optical fiber link connecting two nodes. The optical service channel (OSC) communicates an optical reference parameter over the fiber link. An optical parameter of the OSC transmitted over the fiber link is measured. By recovering the optical reference parameter from the OSC and using the measured optical parameter, certain optical properties may be determined including link loss, multi-path interference, and chromatic dispersion. When measuring chromatic dispersion, one of the fiber links serves as a synchronization reference and the other is the link being measured.

Growing community of inventors

Kensington, MD, United States of America

Vipul Bhatnagar