Tyco Telecommunications (us) Inc.

Bell Communications Research, Inc.

At&t Bell Laboratories

Jedai Broadband Networks Inc.

Chinlon Lin

Bo Pedersen

Morten Nissov

Michael A Mills

Anatoly Frenkel

Alexei N Pilipetskii

Gee-Kung Chang

Neal S Bergano

Evan Lee Goldstein

Ekaterina A Golovchenko

Franklin Webb Kerfoot, Iii

Thirumalai Venky Venkatesan

Stuart M Abbott

George T Harvey

Gerardo Beni

Stephen G Evangelides, Jr

Thomas J Bridges

Susan Hackwood

Charles A Burrus, Jr

Anhui Liang

Lars E Eskildsen

Muhammed Z Iqbal

A hybrid Raman-EDFA provides gain equalization over the C-band and L-band. The hybrid Raman-EDFA includes a Raman section producing a Raman gain and an EDFA section producing an EDFA gain complementing the Raman gain. The EDFA section preferably includes a highly inverted, single-stage EDFA to produce the complementing EDFA gain shape. One embodiment of the EDFA section includes a high return loss termination located after the erbium fiber to receive unabsorbed pump power. Multiple hybrid Raman-EDFAs can be connected in an amplifier chain in a transmission system. The transmission system preferably provides a dispersion map including regular composite fiber spans followed by at least one compensating span of negative dispersion fibers. The Raman sections of the hybrid Raman-EDFAs are preferably coupled to negative dispersion fiber in the transmission system.

Hybrid Raman/erbium-doped fiber amplifier and transmission system with dispersion map

A test apparatus includes a broadband noise source, a test station, and a spectrum analyzer. A method using the test apparatus to measure the spectral gain of an erbium doped fiber amplifier (EDFA) under test includes steps of providing an optical signal from a broadband noise source to an input of the EDFA under test, measuring a power at a test wavelength at an output of the EDFA under test, adjusting the test wavelength, and repeating the steps of measuring and adjusting for a predetermined number of times.

Method and apparatus to measure gain spectra of erbium doped fiber amplifier

A method of increasing capacity on a long-haul undersea cable system having at least one optical fiber, said method comprising interleaving counter-propagating forward-propagating and backward-propagating signals in forward and backward channels on a common optical fiber, wherein the wavelength offset between said forward and backward channels is typically half of the channel spacing of co-propagating signals.

System and method for increasing capacity of long-haul optical transmission systems

A dispersion compensator provides dispersion compensation to a WDM optical signal having a plurality of channels located at different wavelengths and traveling in an optical transmission path. The dispersion compensator includes an optical splitter adapted to receive the WDM optical signal. The optical splitter has first and second output ports such that a subset of the plurality of channels are directed along the first output port and remaining ones of the plurality of channels are directed along the second output port. A dispersion compensating element is coupled to the first output port and a multiplexing element having a first input port is coupled to second output port of the optical splitter. The multiplexing element also has a second input port coupled to the dispersion compensating element and an output port on which the subset of channels and the remaining ones of the channels are recombined.

Chromatic dispersion compensator providing dispersion compensation to select channels of a wavelength division multiplexed signal

A WDM optical communication system is provided that includes a transmitter and a receiver. An optical fiber transmission path couples the transmitter to the receiver. The transmission path includes at least one repeater having an optical amplifier located therein. A dispersion compensator is disposed at an intermediate point along the transmission path. The intermediate point is located outside of the repeater. The compensator includes a wavelength routing device for dividing a signal having a prescribed bandwidth into a plurality of distinct sub-bands. A plurality of output paths is provided for respectively receiving the plurality of distinct sub-bands. The dispersion compensator also includes a dispersion compensating optical element coupled to each of the output paths. Each dispersion compensating optical element substantially compensates for dispersion at a prescribed wavelength within the bandpass of its respective sub-band. A coupler recombining the distinct sub-bands and couples them back onto the optical fiber transmission path.

Method and apparatus for providing chromatic dispersion compensation in a wavelength division multiplexed optical transmission system

A method of operating a hybrid fiber coax transmission system to provide Fiber to the Home Office (FTTHO) functionality comprises directing, via a fiber portion of the transmission system, first wavelength division multiplexed (WDM) optical signals corresponding to a first category of subscriber service. The first wavelength division multiplexed WDM optical signals, which are within a first wavelength band, originate at a primary hub or headend and are sent to a plurality of fiber nodes where they are converted to respective electrical signals. The converted electrical signals are transmitted, via a coaxial cable portion of the transmission system, to the homes of individual subscribers. The method further comprises a step of exchanging, via a fiber portion of the transmission system, demultiplexed second WDM optical signals corresponding to fiber-to-the-home office (FTTHO) service between a headend and the home of at least one of the individual subscribers.

Fiber to the home office (FTTHO) architecture employing multiple wavelength bands as an overlay in an existing hybrid fiber coax (HFC) transmission system

In a multiwavelength lightwave communications system automatic self-power regulation on a channel-by-channel basis is achieved with a cascade of multiwavelength amplifier modules (200), wherein each multiwavelength amplifier module in the cascade includes a plurality of pump-shared parallel fiber amplifiers (208) operated in gain-saturation and connected between an optical demultiplexer (203) and multiplexer (209). An optional first gain stage (202) improves performance with higher optical signal-to-noise ratio. By self-regulating the power in each channel, the communications system is scalable, allowing the system to grow without deleterious effects due to power spread.

Self-regulating multiwavelength optical amplifier module for scalable

A noise limiter for a binary circuit in which a thin film superconductor is put in shunt between a transmission line and ground. The thin film exhibits a gradual transition region as a function of current between normal conduction and the completely superconductive state. The dimensions of the thin film are chosen such that a high level signal on the transmission line falls in the gradual transition region and the impedance of the shunt is greater than the characteristic impedance of the transmission line while a noise component on the low level signal falls in the superconductive region and therefore is reflected by the zero-impedance shunt.

Superconducting noise discriminator

Filter arrangements (400,500,600) are disclosed for tunable channel selection in optical wavelength division multiplexed systems. Each filter arrangement has an etalon device (e.g. 401-403) as a simple, compact, in-line component which is rotatably adapted for interposing between the ends of fiber optic cables for interconnecting the cables. An optical beam emanating from a free end of each cable end is focused and directed to the etalon device by a collimated lensed connector (e.g. 411). Identical etalon devices may be stacked and ganged for rotation in unison to increase the number of system channels that may be propagated. Non-identical etalon devices may be stacked and made independently rotatable to increase the free spectral range of the system.

Etalon filters for optical channel selection in wavelength division

An articulating waveguide arm assembly, comprising long arm segments, (11, 12, 15, 17, 19) and short corner segments (13, 14, 16, 18) has a single-mode hollow dielectric waveguide located inside each segment and an optically reflecting device (33, 34, 37, 38, 39) located at the end of each segment. The waveguide assembly is mechanically affixed to a robot assembly having protruding side shields (65, 66). The robot assembly includes a pair of long arms (61, 62) corresponding to a pair of the waveguide arms (15, 17). Another waveguide arm segment (12) of the waveguide assembly passes over the protruding side shields and terminates in a pair of successive corner segments (13, 14) for enabling a laser beam propagating through this long arm segment to enter into one of the pair of long waveguide segments (61). The robot arm segments control the orientation of corresponding articulating waveguide arm segments, whereby a laser beam entering the articulating waveguide arm assembly will exit from the waveguide assembly positioned and oriented as determined by the positions and orientations of the robot arm segments.

Waveguide robot system for laser beam

Single longitudinal mode operation is achieved and maintained under CW and high speed (Gbps) current modulation conditions by a short coupled cavity laser including a short cavity semiconductor laser having two parallel mirror facets and a reflective surface spaced apart from and in predetermined relationship with one of the mirror facets. A short external cavity resonator is formed between the one mirror facet and the reflective surface. In general, the laser cavity length is related to the external cavity resonator length by the equation, nL=md, where nL is the effective optical length of the injection laser, d is the length of the external cavity resonator, and m is a positive number preferably between 2 and 10.

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Holmdel, NJ, United States of America

Chinlon Lin