Lucent Technologies Inc.

Meriton Networks US Inc.

Other

Fitel USA Corporation

Caci, Inc. - Federal

Photuris, Inc.

Andrew John Stentz

Kenneth L Walker

Per Bang Hansen

Torben N Nielsen

Stephen G Grubb

Jefferson L Wagener

Thomas Andrew Strasser

Rolando Patricio Espindola

Karsten Rottwitt

Paul Francis Wysocki

William Alfred Reed

Mei Du

David John DiGiovanni

David Alan Ackerman

Alan Frank Evans

Ashish Madhukar Vengsarkar

Lars Erik Eskildsen

Liming Zhang

William Crossley Dautremont-Smith

Justin Boyd Judkins

Arlee Virgil Smith

Douglas P Holcomb

Stephan Wielandy

Jinendra Kumar Ranka

Kenneth L Bacher

Neil Allan Jackman

Isaac Ryazansky

Seo Y Park

Robert B Lee

Thomas C Jones

Jesse Joel Smith

Kenneth R Roberts

Stephen W Granlund

Jefferson Lynn Wagener

Disclosed here are methods, devices, and systems for generating an output light beam for a pulsed laser. An example method may comprise generating one or more pump optical beams comprising at least two photons having a pump wavelength. A first nonlinear stage may convert the at least two photons to a first photon having a first wavelength that is half of the pump wavelength. The first optical beam may be caused to spatially overlap with a seed optical beam. At least two second nonlinear stages separated by a gap may be used to convert, based on the seed optical beam, the first photon to a second photon having a second wavelength and a third photon having a target wavelength greater than the pump wavelength. A third nonlinear stage may convert the second photon to a fourth photon and a fifth photon each having the target wavelength or having a wavelength within an offset range of the target wavelength.

Multi-stage nonlinear process for efficient wavelength conversion

An optical switch includes at least one input port for receiving a plurality of channel wavelengths of an optical signal and a plurality of output ports. A plurality of wavelength selective elements are also provided, which each select a channel wavelength from among the plurality of channel wavelengths received at the input port. A plurality of optical elements are respectively associated with the plurality of wavelength selective elements. Each of the optical elements direct one of the selected channel wavelengths, which are selected by the associated wavelength selective element, to any one of the output ports independently of all other channel wavelengths and with a selectively variable degree of attenuation. The switch also includes a controller for adjusting a configuration of the optical elements to provide the channel wavelengths with the selectively variable degree of attenuation.

Method and apparatus for providing gain equalization to an optical signal in an optical communication system

An improved tapered fiber bundle (TFB), or assembly including a TFB, mitigates undesirable reflections from optical discontinuities at the input ends of the multimode fibers of the TFB by suppressing the coupling of signal light into modes that can produce undesired reflections. Means are provided for managing the mode field of injected signal light so that it remains substantially confined to the core of the central TFB fiber until it is past the region where it can interact with the multimode fibers of the TFB.

Pumping arrangement for fiber amplifiers with reduced reflective feedback

A method and apparatus for automatically controlling the gain of an optical amplifier. The method begins by establishing a setpoint for ASE power within a given wavelength range generated by the optical amplifier. The pump power supplied to the optical amplifier is adjusted to maintain the ASE power at the established setpoint. The setpoint for the ASE power is adjusted based at least in part on changes in signal input power.

Optical amplifier having automatic gain control using the amplified spontaneous emission as the monitoring parameter

A method and apparatus is provided for automatically controlling the gain of an optical amplifier. The method begins by generating a first control signal based on a feed-forward error signal and a second control signal based on the feedback error signal. Next, the pump source is adjusted in accordance with the control signals. In this way both the speed of a feed-forward arrangement and the accuracy of a feedback arrangement can be achieved.

Optical amplifier having automatic gain control with improved performance

Optical fiber communication system employing wavelength converter for broadband transmission

A transmission fiber for use in a Raman amplified optical communication system is formed to exhibit certain characteristics that limit modulation instability and four-wave mixing in the amplification region, thus reducing the noise component present in the transmission system. In particular, the group-velocity dispersion (denoted as D and measured in terms of ps/nm-km) is restricted to be either non-positive or greater than &plus;1.5 ps/nm-km in the pump wavelength range of interest (a typical pump wavelength range being 1430-1465 nm). Preferably, the magnitude of the dispersion is kept below a value of 10 ps/nm-km in the signal wavelength range of interest (e.g., the &ldquo;C&rdquo; band or &ldquo;L&rdquo; band). Four-wave mixing is reduced by ensuring that the zero-dispersion frequency of the transmission fiber is not centered between the pump frequency and a frequency experiencing Raman gain.

Raman amplified optical system with reduction of four-wave mixing effects

A soliton pulse generator is formed by providing an input continuous wave, stimulating Brillouin scattering of an input wave having a frequency determined by the frequency of the input continuous wave to generate a backscattered wave, coupling a continuous wave having a frequency determined by the input continuous wave with the backscattered wave to generate a sinusoidal output signal, and then compressing the sinusoidal output to form a soliton pulse train. Because the wavelength shift of the backscattered wave is essentially independent of the input wavelength and power, coupling of the second wave and the backscatterred wave results in a highly stable and controllable sinusoidal output signal. A highly stable and controllable soliton pulse train is provided by compressing the sinusoidal signal with use of a dispersion decreasing fiber or with use of an alternative pulse compressing device.

Soliton pulse generator

A Raman amplified transmission includes at least two pump sources to provide amplification to optical signals residing in the C-band (1530-1562 nm) and L-band (1574-1604 nm). The pump signals are chosen so as to provide for a relatively flat and wide composite gain spectrum with a width at least 50% greater than that generated by a monochromatic pump, while also chosen so as to prevent any four-wave mixing products from being in either the C- or L-bands.

Reduction of four-wave mixing in raman amplified optical transmission systems

The use of a co-propagating fiber Raman amplifier in an optical WDM transmission system has been found to be practical in the situation where the fiber amplifier is operated into depletion and the characteristics of the input signals are controlled to exhibit a reduced integrated relative intensity noise (RIN) over the fiber crosstalk bandwidth. In particular, the reduction in the integrated RIN can be achieved by increasing the number of input channels (by adding more messages or simply using dummy channels), encoding the data in a particular fashion to reduce the integrated RIN, or decorrelating the plurality of N input signals below a predetermined, relatively low frequency (for example, 2 MHz).

WDM optical communication system using co-propagating Raman amplification

A fiber Raman amplifier is configured to use a co-propagating Raman pump source, which may be beneficial in a variety of system configurations (for example, in bidirectional communication systems). By carefully configuring the pump source characteristics, sufficient optical gain can be achieved in the co-propagating arrangement, the characteristics including: (1) using an optical pump power of at least 50 mW, (2) having a relatively large spectral bandwidth within the pump (to suppress SBS); and (3) a frequency difference between all longitudinal pump modes of each pump laser being separated by at least the walk-off frequency between the pump laser frequency and the signal frequency, and all intense longitudinal modes between different pump lasers being separated by at least the electrical bandwidth of the communication system.

Optical communication system with co-propagating pump radiation for raman amplification

In an optical communication system, the signal power level injected into each of one or more optical fiber spans is reduced so as to suppress undesired non-linear effects. This reduction in injected signal level is made possible by remotely pumped amplification in the spans that are affected.

Method of optical signal transmission with reduced degradation by non-linear effects

The present invention is directed to an optical communication system and optical signal amplifier for amplifying said optical signal having at least a first and a second wavelength as it propagates therethrough. The optical signal amplifier includes an input port; an output port; an optical medium, wherein a portion of the optical medium comprises a plurality of optical paths corresponding to the first and second wavelengths of the optical signal; a light radiation generator capable of coupling light radiation of a plurality of light radiation wavelengths related to the first and second wavelengths of the optical signal into each of the optical paths, whereby the first and said second wavelengths are amplified by Raman amplification; and an optical combiner for recombining the first and second wavelengths of the optical signal to generate the amplified optical signal.

Broadband optical amplification system

An optical fiber grating device including a length of optical fiber having a predetermined fundamental mode effective guide index and a longitudinally tapered region for accessing a fundamental mode of light. The tapered region has a grating with a predetermined light spectral shaping property that shapes the light spectrum of the fundamental mode. A coating surrounds the tapered region of the fiber for modifying the fundamental mode effective guide index of the fiber in order to change the spectral shaping property of the grating.

Tapered optical fiber grating devices with variable index coatings for modifying guide properties of the fundamental mode

In accordance with the invention an optical fiber communication system comprising a source of optical signals and an optical fiber transmission line is provided with one or more multiple-order distributed Raman effect amplifiers downstream of the source for amplifying the transmitted signals. As compared with a communication system using conventional first order Raman amplifiers, multiple-order amplifier systems can have reduced noise, longer fiber span lengths and reduced nonlinearities. In a preferred embodiment the system uses signal wavelengths in the range 1530-1570 nm, first order Raman pumping at 1430-1475 nm and second order pumping at about 1345 nm. Advantageously, the second order pump light is copropagating with the signal light and the first order pump is counterpropagating with the signal.

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Clinton, NJ, United States of America

Andrew John Stentz