Lucent Technologies Inc.

At&t Bell Laboratories

Bell Telephone Laboratories

Agere Systems Guardian Corp.

American Telephone and Telegraph, Co.

Agere Systems Optoelectronics Guardian Corp.

Lawrence Warren Stulz

Christopher Richard Doerr

Clinton R Giles

Charles H Joyner

David John Bishop

Bradley Paul Barber

Rene R Ruel

Vladimir Anatolyevich Aksyuk

Julian Stone

Rene Henri Monnard

James Albert Walker

Corrado Pietro Dragone

Larry Allen Coldren

Patrick P Iannone

Martin Zirngibl

Robert William Tkach

Andrew Roman Chraplyvy

Ivan P Kaminow

Uziel Koren

Randy Clinton Giles

Barry Irwin Miller

Dries Van Thourhout

John Evan Johnson

Leonard Jan-Peter Ketelsen

Liming Zhang

Tingye Li

Dirk Joachim Muehlner

Weiguo Yang

Joseph Carmine Centanni

Ellsworth C Burrows

Pietro Arturo Giovanni Bernasconi

Nicholas J Sauer

Rudolph Conrad Schweizer

Vladimir J Aksyuk

Andrew Gompers Dentai

Spot-size conversion for interfacing a first optical element having a higher refractive index to a second optical element having a lower refractive index is achieved through the use of two optical star couplers coupled to each other through a plurality of optical paths embedded in a planar waveguide. The beam from the high refractive index element is introduced into a high numerical aperture (NA) star coupler, which directs the beam through a plurality of optical paths to a second star coupler with a lower numerical aperture than the first star coupler so that its output spot-size is larger. The output port of the second star coupler is interfaced to the lower refractive index element. Wavelength selection can be provided by making non-zero path-length differences between adjacent optical paths between the two star couplers. Wavelength tunability can be provided by including phase shifters in the paths between the two star couplers to alter the effective optical lengths of the paths to selectively produce the desired phase interference pattern at the desired wavelength.

Method and apparatus for mode conversion

A high power multi-frequency laser includes a laser cavity defined by reflective elements, a frequency routing device in the cavity comprising a plurality of frequency selective pathways, a first set of optical amplifiers optically coupled to a first end of the frequency routing device, and a second set of optical amplifiers optically coupling a second end of the frequency routing device and a first one of the reflective elements. The high power multi-frequency laser further includes a power combiner. The power combiner is optically coupled to the first set of optical amplifiers and a second one of the reflective elements and combines the outputs of the first set of optical amplifiers such that a common output for the multi-frequency laser is provided. The common output of the present invention provides a single output from the multi-frequency laser having a high output coupling efficiency.

High power multi-frequency laser

A planar lightguide circuit (PLC) phase shifter is fabricated on a chip which exhibits reduced thermal crosstalk by reducing the thermal resistance between the waveguide cores and the thermal &ldquo;ground&rdquo; (e.g., a heat sink) compared to the thermal resistance between the waveguide cores. This is accomplished by removing some of the glass from the backside of the chip over a small area under the phase shifters, depositing metal on the backside, and soldering it to a copper block heat sink.

Phase shifters with reduced thermal crosstalk

Temperature compensation of a wavelength-division-multiplexed (WDM) passive optical network (PON) communication system uses power measurements from each of it remote nodes (RNs) to adjust the frequency of an associated multifrequency laser (MFL). Changes in the power level at each RN caused by frequency drift of its waveguide grating router (WGR), due to changes in the WGR temperature, is determined by monitoring the power level received at each RN and corrected by appropriate changes in the temperature of the associated MFL. The WGR uses one output port (e.g., channel,) which is looped-back through the WGR a second time to increase the temperature sensitivity of the power measurements. A temperature-control algorithm controls the temperature of the MFL as a function of changes in the received power at the WGR.

Temperature compensated multi-channel, wavelength-division-multiplexed passive optical network

A hybrid integrated optical transmitter comprising a wavelength selectable laser (WSL) source coupled to an optical amplifier/modulator has been realized. Disposed between the optical combiner and the optical amplifier/modulator is an &ldquo;optical isolator.&rdquo; The optical isolator includes at least a Faraday rotator and, either solely or in combination with a single polarizer and/or half-wave plate is used to selectively rotate and pass polarized light egressing from the wavelength selectable laser source. Optical isolation is achieved by the egressing radiation from and back reflections incident on the laser source being at two mutually exclusive orthogonal polarization states or by the reflections being totally extinguished. Advantageously, the laser source is unresponsive to orthogonally polarized light, and hence any unwanted back reflections do not substantially affect the operating characteristics of the laser(s). Optical isolation may be further improved, however, with the use of an additional polarizer positioned in front of the Faraday rotator to totally extinguish the polarized back reflections. Preferably, a latching Faraday rotator is used. As such, permanent magnets are not needed to maintain the latching Faraday rotator in its saturated state, and substantially reduces cost, size and complexity of the transmitter package. The wavelength selectable laser source is integrated on a single substrate with an optical combiner that directs the radiation to the optical amplifier/modulator, which is integrated on a second substrate. Alternatively, the laser source and optical combiner may be integrated on different substrates.

Hybrid integration of a wavelength selectable laser source and optical amplifier/modulator

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

In accordance with the present invention, apparatus for and method of operating an optical signal monitor is disclosed for providing rapid monitoring of optical signals using a high speed optical modulator. One illustrative optical signal monitor includes (1) a Mechanical AntiReflective Switch (MARS) optical modulator (signal chopper) capable of operating at 10 MHz rates and having a detection bandwidth greater than 100 kHz and (2) a synchronous detector using lock-in detection in a 1550 nm-band WDM optical monitor to enhance detection sensitivity by greater than 30 dB compared to direction detection methods. According to another embodiment, the optical monitor can be used to control adaptive optical amplifier units or equalizer units of a wavelength division multiplexed (WDM) system.

Optical signal monitor for multiwave optical signals

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

A multifrequency laser (MFL) eliminates nonlinearities produced in the 'shared' waveguide of the MFL laser (the section in which all the lightwaves from all the lasers pass) by either making the shared waveguide as short as possible to mimimize the production of mixing product signals or using a channel spacing that is unequal such that any mixing product signals formed from the multifrequency optical laser signal do not overlap in frequency with any of the signals of the multifrequency optical laser signal.

Multifrequency laser having reduced wave mixing

An integrated optical device (e.g., a wavelength router) is formed on a substrate, where the device has a compressive force within the plane of the device and the substrate has at least one non-straight edge. The device is formed by annealing the substrate wafer and then separating the device by cutting along one or more non-straight or curved lines. When the device layer is much thinner than the substrate and when the coefficient of thermal expansion of the substrate material (e.g., silicon) is greater than that of the device material (e.g., silica), the annealing process generates the compressive force. This in turn enables the device to be separated from a wafer by cutting along non-straight lines using either a laser or a milling machine without fear of cracks and fissures propagating over time into the device. The present invention enables manufacturing with greater yields since curved devices, such as wavelength routers, can be more efficiently packed onto a single wafer. The present invention can also reduce crosstalk by eliminating the direct substrate path through which stray light, resulting from misalignments between optical fibers and the device input ports, could otherwise pass.

Non-rectangular optical devices

One aspect of the invention is a Fabry-Perot cavity which has in part a waveguiding portion and in part a nonwaveguiding portion. In this manner, a cavity is constructed whose length would be too short to manipulate effectively if it were comprises exclusively of a waveguiding portion, and whose length might have unacceptable diffraction losses if it were comprised exclusively of a nonwaveguiding portion. In the inventive device the resonant wavelength can be adjusted by varying the length of either the gap or the waveguide or both. The device can be advantageously constructed and aligned using fiber coupling technology.

Optical communication systems using Fabry-Perot cavities

This invention is a new type of Fabry-Perot cavity, and an optical communication system using such a cavity. The inventive Fabry-Perot cavity comprises both a waveguiding portion and a nonwaveguiding portion. In this manner, tunable cavities of desirable mid-range length, necessary to obtain required free spectral ranges, may be fabricated with minimal diffraction losses otherwise associated with cavities of such length. The cavity length may be varied using, for example, piezoelectric elements, and the various cavity elements may be aligned and connected, using fiber connector technology.

Growing community of inventors

Shark River Hills, NJ, United States of America

Lawrence Warren Stulz