Lucent Technologies Inc.

At&t Bell Laboratories

At+t Corp.

Alcatel-lucent USA Inc.

Clinton R Giles

Lawrence Warren Stulz

David John Bishop

David John DiGiovanni

Martin Zirngibl

Bradley Paul Barber

Thomas Huntington Wood

Tingye Li

Rene R Ruel

Emmanuel Desurvire

Victor Mizrahi

Vladimir Anatolyevich Aksyuk

Mohammad Taghi Fatehi

Turan Erdogan

John L Zyskind

Andrew Gomperz Dentai

Jay R Simpson

Ellsworth C Burrows

Herman M Presby

Bernard Glance

Dan Mark Marom

Christophe Jean Dorrer

Inuk Kang

Robert D Feldman

Mihaela Dinu

Song Jiang

Joseph Carmine Centanni

Gerald Nykolak

Stuart A Kramer

Vladimir J Aksyuk

Andrew Gompers Dentai

A communication system adapted to use wavelength (frequency) division multiplexing for quantum-key distribution (QKD) and having a transmitter coupled to a receiver via a transmission link. In one embodiment, the receiver is adapted to (i) phase-shift a local oscillator (LO) signal generated at the receiver, (ii) combine the LO signal with a quantum-information (QI) signal received via the transmission link from the transmitter to produce interference signals, (iii) measure an intensity difference for these interference signals, and (iv) phase-lock the LO signal to the QI signal based on the measurement result. In one configuration, the QI signal has a plurality of pilot frequency components, each carrying a training signal, and a plurality of QKD frequency components, each carrying quantum key data. Advantageously, the system can maintain a phase lock for the QKD frequency components of the QI and LO signals, while the QKD frequency components of the QI signal continuously carry quantum key data.

Phase locking in a multi-channel quantum communication system

A micromirror array is used to form optical apparatus useful in WDM optical networks. In one embodiment, the micromirror array is used to insert a desired attenuation in individual channels for purposes such as equalization. In another embodiment, the micromirror array is used to form an optical monitor useful as an optical spectrum analyzer.

Pixellated WDM optical components

An optical switch uses a MEMS device to insert a highly reflective shutter in a gap between a pair of coaxially aligned fibers. When the switch is closed, an input optical signal passes with little loss through the gap. When the switch is open and the shutter is positioned in the gap, an input optical signal incident on the shutter is reflected back into the input fiber. Such light is diverted by an optical circulator into a new path.

Optical switch

An optical attenuator for use in optical power regulation uses a shutter to control the insertion loss of a gap in a pair of substantially coaxially aligned waveguides, for example a pair of optical fibers. The shutter is part of a MEMS accuator device and is coupled to the movable one of a pair of spaced plates, the movable plate being movable by a voltage applied between the pair of plates. To regulate the power, a small portion of the optical power is abstracted and used to derive a control voltage that is applied to the optical attenuator for varying the attenuation inserted in the optical wave path.

Optical attenuator

Arrayed waveguide grating routers are used to form 1.times.N demultiplexers and N.times.1 multiplexers to form channel drop modules in a WDM optical network. The demultiplexer and the multiplexer are interconnected by optical waveguides in which are inserted optical switches provided by MEMs devices that can be used to reflect incident optical signals backwards for dropping channels or to both transmit and reflect incident optical signals to drop and detect channels.

Wavelength division multiplexed optical networks

Opto-mechanical arrangements for use in light wave paths use actuator wires of a material, such as NiTi, whose length can be shortened by flowing heating current in the wire. The arrangements include switches and attenuator assemblies.

Opto-mechanical components

The specification describes lightwave systems with remotely powered photoelectric generators. Optical power transmitted through the fiber is incident on a remotely located photodiode array. High power conversion efficiency coupled with a specially designed diode array generates sufficient power to operate electromechanical or electrooptic apparatus in the remote station. Long wavelength photodiodes in a circular or polygonal circularly symmetric array are serially connected to increase the voltage to practical operating levels. The photodiodes are fabricated to allow back lighting of the array. The bottom contact layer is made transparent to the wavelength of the power signal. This arrangement allows the contact area to extend over the entire front surface of the diode to reduce contact resistance. It also gives nearly optimum fill factor. The front surface may be metallized so the incident light undergoes a double pass through the absorbing layer.

Long wavelength InGaAs photogenerator

Methods and apparatus for stabilizing or otherwise controlling optical signal power levels in a multi-channel optical communication system. A multi-channel optical signal is detected in a single receiver, and the resulting detected signal is supplied to a correlator. The correlator correlates the detected multi-channel signal with a data signal associated with a particular channel to be controlled in order to generate a measure of the optical signal power of the particular channel. The measure is utilized in a feedback control loop to control an optical signal power level of the particular channel. The correlator may generate the measure of optical signal power by mixing the detected signal and the data signal in an RF mixer, by multiplying the detected signal and a data signal in the form of a unique identifier associated with the particular channel, or by using other suitable correlation techniques. A feedback control processor may be used to process the measure to generate a control signal which is applied to a current source generating current for the particular channel in a multi-frequency laser or other multi-channel optical source. The processor may sequentially monitor and control each of the multiple channels of the multi-channel optical signal using the same receiver and correlator.

Stabilization of a multi-channel optical signal transmitter through

A Wavelength Division Multiplexing (WDM) optical monitor, based on concatenated fiber gratings, uses a single modulator and detector and has high dynamic range and good sensitivity through signal averaging. The WDM optical monitor may be implemented in a time-domain or frequency-domain embodiment and used for SNR measurement of WDM optical signals.

Concatenated fiber grating optical monitor

A system and method for maintaining alignment between a source and router in a Wavelength Division Multiplexed (WDM) fiber optic network. In a preferred embodiment, a narrow band of the wavelengths emitted by the WDM source is designated as a monitor channel. The monitor channel is matched in wavelength to a fiber grating that is located in the optical path between the source and router so that the grating reflects the monitor channel light while allowing all other source light to pass through unimpeded. By monitoring the reflected light and adjusting the source wavelengths to maximize the amount of reflected light, alignment between the source and router is maintained.

System and method for synchronizing an optical source and a router in a

A passive optical network for the downstream dense wavelength division multiplexing communication of data between a host terminal complex (HTC) and a plurality of optical network units (ONUs), and for the upstream communication of data from the ONUs to the HTC. The network includes a routing device for distributing downstream data signals contained in a common frequency band among a plurality of fiber drop lines for providing a corresponding wavelength to a corresponding ONU. The routing device also combines upstream data signals contained in a frequency band other than the downstream common frequency band, which are input to the routing device on the plurality of fiber drop lines, to a multi-wavelength signal which is provided to the HTC. In a preferred embodiment, the upstream data signals are output by the routing device to a broadcast port.

Passive optical network for dense WDM downstream data transmission and

The specification describes lightwave systems with remotely powered photoelectric generators. Optical power transmitted through the fiber is incident on a remotely located photodiode array. High power conversion efficiency coupled with a specially designed diode array generates sufficient power to operate electromechanical or electrooptic apparatus in the remote station. Long wavelength photodiodes are serially connected to increase the voltage to practical operating levels. In a communication system, with an optical signal transmitted with the optical power, multiplexers are used for separating the optical power from the optical signal.

Photogenerator for lightwave networks

In a fiber optic communication system, a multifrequency light source generates a signal having a plurality of discrete and temporally spaced wavelengths. The wavelengths can be modulated with data for transmission in an optic medium. The multifrequency light source is cascaded with a power splitter for dividing the generated signal into a plurality of multifrequency signals of substantially equal power. The wavelengths in the plurality of signals may be modulated with data for transmission in an optic medium to a plurality of optic receivers for retrieval of the data.

Discretely chirped multiple wavelength optical source for use in a

An Add/Drop circuit for use in optical wavelength-division multiplexed systems includes fiber coupled four-port polarized beamsplitters and fiber Bragg grating filters.

Add/drop optical circuit for a wavelength-division multiplexed network

A correlation feedback method and apparatus for multi-channel stabilization of a multi-channel transmitter in which a single external receiver is used to detect the total power output from the multi-channel transmitter and to control each channel by correlating the total power output signal with channel data to measure the channels' signal power and control the output power via a feedback loop. The inventive system is suitable for use with and able to accommodate both integrated lasers and an array of discrete independent lasers; the system is also equally applicable for use with channels comprising random independent data or broadcast data.

Growing community of inventors

Middletown, NJ, United States of America

Clinton R Giles