Massachusetts Institute of Technology

Other

Kristin A Rauschenbach

John D Moores

Farhad Hakimi

Richard A Barry

Hosain Hakimi

Daniel T Moriarty

Steven G Finn

Naimish S Patel

Muriel Medard

Salil A Parikh

Agnes H Chan

A method introduces variable time offsets into a stream of optical pulses. The method includes receiving a plurality of coherent optical pulses, receiving a plurality of control signals, and forming a coherent pulse array (CPA) from each pulse in response to one of the received control signals. Temporal spacings between pulses of each CPA are responsive to the associated one of the received control signals. For optical control signals, response times can be very short. The method further includes transmitting each pulse through a dispersive optical medium. The act of transmitting makes pulses of each CPA overlap to form an interference pattern.

Fast variable optical delay

All-optical bit phase sensors that utilize nonlinear interferometers are described. An all-optical bit phase sensor that utilizes an optical fiber and a detector optically coupled to the core of the fiber, perpendicular to the longitudinal direction of the core, is described. In addition, an electrooptic bit phase sensor that utilizes a semiconductor diode and an electrical detector electrically coupled to the active layer is described. Electrooptical and all-optical phase lock loops, optical processors, and optical networks that utilize these bit phase sensing are also described.

All-optical bit phase sensing

An optical bit rate for communication systems. The optical bit rate converter converts an ultra-high speed optical data stream to a lower rate optical data stream. In one embodiment, the optical bit rate converter converts the ultra-high speed optical data stream to a lower rate optical data stream that can be detected and processed electronically. The optical rate converter includes a buffer presenting a repeating optical data bit pattern, an optical sampler presenting an optical sampling bit stream, and an optical correlator. The optical correlator has a first input in communication with the output of the buffer and a second input in communication with the output of the optical sampler. The optical correlator produces a rate-converted optical data bit stream at its output in response to the repeating optical data bit pattern produced by the buffer and the optical sampling bit stream produced by the optical sampler. In one embodiment, the buffer has a data input and stores an optical data bit stream received from a high speed optical data source. In another embodiment, the optical bit rate converter time dilates the repeating optical data bit pattern received from the buffer. In yet another embodiment, the optical bit rate converter demultiplexes the repeating optical data bit pattern received from the buffer. The invention also relates to a method for rate-converting an ultra-high speed optical data stream to a lower rate optical data stream.

Optical bit rate converter

All-optical bit phase sensing and clock recovery apparatus and methods

A pseudorandom sequence generator including a first feedback shift register having at least one input and at least one output and a first controller having an output in communication with the at least one input of the first feedback shift register; the first feedback shift register operating at a first speed S,and the first controller operating at a second speed S,. In one embodiment the first speed S,of the first feedback shift register is an integer multiple of the second speed S,of the first controller. In another embodiment the first feedback shift register includes a shift register having an input, an output, and at least one tap; and a feedback function generator having a first input in communication with the at least one tap of the shift register, a second input in communication with the output of the first controller, and an output in communication with the input of the shift register; the feedback function generator includes at least one feedback function.

Pseudorandom noise sequence generator

An optical bit error tester for testing an optical device. The optical bit error tester, in one embodiment, includes an optical bit pattern generator, an optical beam divider in communication with the optical bit pattern generator, the optical device being tested and an optical XOR gate. The optical XOR gate in one embodiment includes a first input port in communication with the beam divider and a second input port in communication with the optical device being tested. The optical XOR gate produces an output signal at its output port in response to changes introduced by the optical device under test in the optical bit pattern produced by the optical bit pattern generator. In one embodiment the optical XOR gate includes a non-linear optical loop mirror.

Apparatus and method for comparing optical bits

An optical memory and an optical random and pseudo-random pattern generator for ultra-high-speed time-domain multiplexing multi-access networks are described. The optical memory and pattern generators include an optical ring resonator, an optical amplifier, a bistability generator, an optically-controlled stabilizing element, and a coupling element. Such devices are capable of storing high data rates for long periods of time.

Growing community of inventors

Lexington, MA, United States of America

Kristin A Rauschenbach