E-tek Dynamics, Inc.

Donna S Yu

Jing-Jong J Pan

Ming M Shih

Yu-Li Ko

Weiti Wu

Simon Xiaofan Cao

Yuan Shi

The present invention provides for a fiber optic coupler of first and second optic fibers formed by a length of the two fibers. The first optic fiber along the length has a different core diameter than that of the second optic fiber. At the both ends of the length the first and second optic fibers are twisted about each other with a central portion in which said first and second optic fibers are fused substantially parallel to each other. The resulting coupler is such that an input light signal is split into output light signals in a predetermined power ratio on the two optic fibers with the coupled power ratio relatively insensitive for a predetermined range of signal wavelengths.

Broad bandwidth, single mode fiber optic coupler and method of

The present invention provides fiber optic couplers for use with at least three optic fibers. The optic fibers arranged in a linear array, that is, the optic fibers are coupled side by side. The fibers along either end of the linear-array are coupled only to a single fiber, while the remaining fibers are generally coupled between only two adjacent fibers. Generally, at least one of the fibers has a propagation constant different that the other fibers. Such variations in the propagation constant are used to vary the coupling coefficients among the fibers of the linear-array, thereby providing a repeatable mechanism, to vary coupled power ratios among the fibers of the coupler. Theoretical calculations and empirical experience have shown that varying the propagation constant of fibers among a linear-array, generally by pre-pulling the fibers by varying amounts, allows repeatable manufacturing of 1.times.3, 1.times.4, 4.thrfore.3, 1.times.N and even N.times.N fiber couplers having even coupled power ratios.

1XN and NXN fiber optic couplers

The present invention provides fiber optic couplers for use with at least three optic fibers. The optic fibers arranged in a linear array, that is, the optic fibers are coupled side by side. The fibers along either end of the linear-array are coupled only to a single fiber, while the remaining fibers are generally coupled between only two adjacent fibers. Generally, at least one of the fibers has a propagation constant different than the other fibers. Such variations in the propagation constant are used to vary the coupling coefficients among the fibers of the linear-array, thereby providing a repeatable mechanism, to vary coupled power ratios among the fibers of the coupler. Theoretical calculations and empirical experience have shown that varying the propagation constant of fibers among a linear-array, generally by pre-pulling the fibers by varying amounts, allows repeatable manufacturing of 1.times.3, 3.times.3, 1.times.4, 4.times.4, 1.times.N and even N.times.N fiber couplers having even coupled power ratios.

1.times.N and N.times.N fiber optic couplers

Multiplexer and demultiplexer devices for Dense WDM networks are described. The devices use an optical circulator, a plurality of bandpass wavelength division units and fiber Bragg gratings arranged in the optical fibers interconnecting the optical circulator and the bandpass wavelength division units. The optical circulator is connected to a network optical fiber and the bandpass wavelength division units are connected to a plurality of input/output optical fibers. Each fiber Bragg grating has a narrow wavelength reflection band about a predetermined wavelength and is arranged so that optical signals at wavelengths differing from predetermined wavelengths of the first optical fibers connected to a bandpass wavelength division unit are blocked and reflected. Depending upon the direction of the optical circulator, the device may be a multiplexer or a demultiplexer. Alternatively, a 3dB optical coupler may be used in place of the optical circulator with a corresponding rearrangement of the fiber Bragg gratings.

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Danville, CA, United States of America

Donna S Yu