At&t Bell Laboratories

American Telephone and Telegraph, Co.

Yosi Shani

Charles H Henry

Rudolf F Kazarinov

Kenneth J Orlowsky

Rodney C Kistler

Aasmund S Sudbo

A wavelength selective structure is coupled to an adiabatic Y-coupler via a multimode section which supports both symmetric and antisymmetric modes. One single mode branch of the coupler converts guided light to a symmetric mode, whereas the other single mode branch converts guided light to an anti-symmetric mode. The structure, which includes a pair of single mode waveguide arms coupled to the common section and a reflection device (such as a grating or ROR) located in each arm, converts reflected light from a symmetric mode to an anti-symmetric mode and conversely. Applications described include a channel dropping filter and channel balancing apparatus for WDM systems, and a dispersion compensator for fiber optic systems.

WDM systems incorporating adiabatic reflection filters

Adiabatic reflection apparatus

A TE-TM polarization manipulating (i.e., splitting, combining or filtering) device is constructed from substrate-supported dielectric thin film waveguides. In a 3-port device, two waveguides have cores of different materials and different effective refractive indices. The waveguide cores overlap in a first transition section and one waveguide core has an adiabatic taper; in this section they also separate adiabatically in and are coupled to a second (e.g., output) section where the waveguides are physically separate and optically decoupled. In a 4-port device, two additional waveguides are coupled in a second adiabatic transition section to the first transition section to enable TE or TM modes to be coupled straight through the device from one input port to a directly opposite output port or to be crossed-over from one input port to a diagonally opposite output port.

Adiabatic polarization manipulating device

An optical device is disclosed which provides wavelength multiplexing/demultiplexing utilizing a plurality of focusing Bragg reflectors. Each Bragg reflector includes a plurality of confocal (i.e., common foci) elliptical grating lines, with the exit/entrance ports of the input/output waveguides located at the foci of the ellipse. By virtue of the elliptical design, the signal propagating outward from the exit port of the input waveguide will be reflected by the appropriate Bragg reflector and focused into the entrance port of the appropriate output waveguide. When each Bragg reflector exhibits a different ellipticity, but shares one common focal point, optical multiplexing/demultiplexing may be achieved. Optical filtering may be achieved when all Bragg reflectors are designed to have common foci.

Optical multiplexer/demultiplexer using focusing Bragg reflectors

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Murray Hill, NJ, United States of America

Yosi Shani