Yuan Hua Li

US Patent:

6351581, Feb 26, 2002

Filed:

Mar 17, 1998

Appl. No.:

09/040477

Inventors:

Christopher Richard Doerr - Middletown NJ
Yuan P. Li - Duluth GA

Assignee:

Agere Systems Optoelectronics Guardian Corp. - Orlando FL

International Classification:

G02B 626

US Classification:

385 24, 359124

Abstract:

An optical add-drop multiplexer (ADM) avoids waveguide crossings by being constructed in the form of a Mach-Zehnder interferometer having a demultiplexer/multiplexer (demux/mux) pair in each of its arms. Each demux/mux pair is interconnected by coherent connecting paths having heating elements for increasing the path length of selected connecting paths. Waveguide optical couplers having asymmetric transfer functions are used at the input and output of the ADM. These couplers cooperate with the activated heating elements to add and/or delete a selected optical channel to/from an optical transmission path. Each coherent connecting path includes a number of waveguides. The end-to-end transmission characteristic of the ADM through each individual waveguide has a Gaussian shape. These Gaussian shapes are designed intersect at their -3 dB wavelengths so that the end-to-end transmission characteristic of the ADM is flat.

US Patent:

55027814, Mar 26, 1996

Filed:

Jan 25, 1995

Appl. No.:

8/378162

Inventors:

Yuan P. Li - Scotch Plains NJ
Raymond Wolfe - New Providence NJ

Assignee:

AT&T Corp. - Murray Hill NJ

International Classification:

G02F 1295
G02B 626
G01B 902

US Classification:

385 4

Abstract:

Integrated optical devices which utilize a magnetostrictively, electrostrictively or photostrictively induced stress to alter the optical properties of one or more waveguides in the device are disclosed. The integrated optical devices consist of at least one pair of optical waveguides preferably fabricated in a cladding material formed on a substrate. A stress applying material, which may be a magnetostrictive, electrostrictive or photostrictive material, is affixed to the upper surface of the cladding material near at least one of the optical waveguides. When the appropriate magnetic, electric or photonic field is applied to the stress applying material, a dimensional change tends to be induced in the stress applying material. The constrained state of the stress applying material, however, caused by its adhesion to the cladding material, causes regions of tensile and compressive stress, as well as any associated strains, to be created in the integrated optical device. By positioning one or more optical waveguides in a region of the device which will be subjected to a tensile or compressive stress, the optical properties of the stressed waveguide may be varied to achieve switching and modulation.