At&t Bell Laboratories

Bell Telephone Laboratories

Lucent Technologies Inc.

Tingye Li

Clinton R Giles

Thomas Huntington Wood

Patrick P Iannone

Robert William Tkach

Andrew Roman Chraplyvy

Ivan P Kaminow

Julian Stone

Lawrence Warren Stulz

Willis Martin Muska

James Emanuel Goell

Dan L Bisbee

An optical communication system is disclosed including an all-optical device whose output modulated optical beam is locked to an input modulated optical beam. In a specific embodiment of the system, the device may be a self-electro-optic effect device (SEED), which is operated as an oscillator by means of an associated tank circuit. Such an embodiment permits recovery of a clock frequency from a bit stream which is input into the device. When the output of the device is directed into an optical decision element, an all-optical regenerator may be realized.

Optical communication by injection-locking to a signal which modulates

For a group of optical amplifiers, pump beams from an array of lasers are mixed together to form a plurality of composite pump beams. Each composite pump beam is distributed to the pump port of a particular optical amplifier. The composite pump beam improves the reliability of each optical amplifier. Rather than having catastrophic failure of an optical amplifier occasioned by the failure of its pump laser, it is now possible to maintain full operation of the group of optical amplifiers even though one or more lasers fail.

Fault tolerant optical amplifier arrangement

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

Automatic apparatus for precisely aligning first and second optical fibers (11, 13) end to end. The first optical fiber is coupled to an optical source (12). An end face (15) of the second fiber abuts an end face (14) of the first fiber. Detector apparatus (16-19 or 51) affixed to the circumference of the second fiber monitors the light transmitted in the cladding of the second fiber and generates a corresponding electrical signal therefrom. This signal is fed to electronic circuitry (27, 28, 7, 8, 31, 32 or 52, 61, 63, 64, 66, 67) which selectively activates fiber moving transducers (41, 42 or 69, 70 or 81, 82) to move the fiber end faces until the cladding light monitored is a minimum. This will maximize the transmitted light between the fiber cores. Once this optimum alignment is achieved, this position is maintained by the transducers.

Automatic alignment apparatus for optical fiber splicing

A multimode optical waveguide having refractive index n, width a, and length L is provided with branches on either side of each end and has an electrode pattern capable of differentially delaying the even modes and the odd modes of light of wavelength .lambda. in the waveguide when voltage is applied. When the length L is a half-critical length, calculated to be (2na.sup.2 /.lambda.), or multiple thereof, the device acts as an amplitude modulator or switch. At least one of the electrodes typically is very slender and has a width less than about one-fourth the waveguide width a, so as to achieve different effects on the different modes by causing a laterally nonuniform but bilaterally symmetric refractive index change in the waveguide.

Multimode optical modulator/switch

There is disclosed a variety of arrangements for tapping a portion of the signal power from an optical fiber waveguide without requiring that the fiber be terminated or broken. Power is coupled out of the fiber waveguide, which typically includes an inner core surrounded by a lower refractive index outer cladding, by disposing a dielectric body in a coupling relationship with an intermediate length of the fiber from which all or most of the cladding has been removed or, alternatively, which is bent to cause a portion of the power to radiate out of the inner core into the outer cladding of the fiber. The dielectric body couples power out of the fiber provided its index of refraction is approximately equal to, or greater than, that of the fiber cladding material. The power coupled out by the dielectric body is converted to a representative electrical signal by a photodetector disposed adjacent to the dielectric body.

Optical fiber power taps

In a chemical vapor deposition (CVD) process for manufacturing a fiber optic preform, a glass rod is inserted into the preform during the deposition of the core layer. This yields a fiber having a longitudinal eccentric index inhomogeneity which is close to the axis of the fiber.

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Rumson, NJ, United States of America

Tingye Li