Desmond Rodney Lim

US Patent:

6631225, Oct 7, 2003

Filed:

Apr 24, 2001

Appl. No.:

09/841464

Inventors:

Kevin K. Lee - Cambridge MA
Kazumi Wada - Lexington MA
Desmond Lim - Cambridge MA
Lionel C. Kimerling - Concord MA

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

G02B 626

US Classification:

385 28, 385 43, 385 49, 385 50

Abstract:

A mode coupler that enables low-loss coupling between optical modes of two waveguides with different index difference. The mode size and the effective index are gradually changed between two waveguides to gradually transform the mode shape, size, and speed with minimum power loss. The mode coupler is useful for coupling the mode of an optical fiber waveguide with low index difference to the mode of a planar high index difference waveguide, and vice versa.

US Patent:

6661938, Dec 9, 2003

Filed:

Sep 25, 2001

Appl. No.:

09/963026

Inventors:

Desmond R. Lim - Cambridge MA
Anuradha Agarwal - Weston MA
Lionel C. Kimerling - Concord MA

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

G02B 600

US Classification:

385 12, 385129

Abstract:

An integrated optical sensor using optical waveguide micro-cavity resonators. Using a laser and a detector it is possible to detect changes in the position of the resonance position, in wavelength or frequency, of one or more modes of the resonator. The change in resonance can be made dependent on chemicals, which have been adsorbed by chemically or biologically sensitive material provided in close proximity to the resonator.

US Patent:

6690871, Feb 10, 2004

Filed:

Jun 27, 2001

Appl. No.:

09/893263

Inventors:

Kevin K. Lee - Cambridge MA
Desmond Lim - Cambridge MA
Kazumi Wada - Lexington MA
Lionel C. Kimerling - Concord MA

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

G02B 610

US Classification:

385129, 385124, 385125, 385126

Abstract:

A planar waveguide that has a graded index layer at the core/cladding interface to reduce scattering losses due to core/cladding interface roughness. The refractive index at the core/cladding interface is changed from that of the core to that of cladding gradually by having a graded index layer. The graded index layer reduces the scattering of light traveling in the waveguide by reducing the effect of the roughness at the abrupt interface between the core and the cladding. Using a proper design, the graded index layer also minimizes the modal and polarization dispersion of the optical mode traveling in the waveguide.

US Patent:

6697551, Feb 24, 2004

Filed:

Jun 26, 2001

Appl. No.:

09/978310

Inventors:

Kevin K. Lee - Cambridge MA
Kazumi Wada - Lexington MA
Desmond Lim - Cambridge MA
Lionel C. Kimerling - Concord MA

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

G02B 626

US Classification:

385 28, 385 43, 385132

Abstract:

A mode transformer that enables low-loss coupling between optical modes of two waveguides with different index difference. The mode size and the effective index are gradually changed between two waveguides to gradually transform the mode shape, size, and speed with minimum power loss. The mode transformer is useful for coupling the mode of an optical fiber waveguide with low index difference to the mode of a planar high index difference waveguide, and vice versa.

US Patent:

6751368, Jun 15, 2004

Filed:

Sep 21, 2001

Appl. No.:

09/961573

Inventors:

Desmond R. Lim - Cambridge MA
Kevin K. Lee - Cambridge MA
Lionel C. Kimerling - Concord MA

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

G02B 612

US Classification:

385 14

Abstract:

Methods of tuning, switching or modulating, or, in general, changing the resonance of waveguide micro-resonators. Changes in the resonance can be brought about, permanently or temporarily, by changing the size of the micro-resonator with precision, by changing the local physical structure of the device or by changing the effective and group indices of refraction of the mode in the micro-resonator. Further changing the asymmetry of the index profile around a waveguide can alter the birefringence of the waveguide and allows one to control the polarization in the waveguide. This change in index profile may be used to change the polarization dependence or birefringence of the resonators.

US Patent:

6850683, Feb 1, 2005

Filed:

Jun 7, 2001

Appl. No.:

09/876392

Inventors:

Kevin K. Lee - Cambridge MA, US
Desmond R. Lim - Cambridge MA, US
Kazumi Wada - Lexington MA, US
Lionel C. Kimerling - Concord MA, US

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

G02B 610

US Classification:

385129, 385130, 385131, 385132, 65386, 216 24

Abstract:

A method of reducing the scattering losses that involves smoothing of the core/cladding interface and/or change of waveguide geometry in high refractive index difference waveguides. As an example, the SOI-based Si/SiOwaveguides are subjected to an oxidation reaction at high temperatures, after the waveguide patterning process. By oxidizing the rough silicon core surfaces after the patterning process, the core/cladding interfaces are smoothened, reducing the roughness scattering in waveguides.

US Patent:

6915029, Jul 5, 2005

Filed:

Mar 7, 2003

Appl. No.:

10/384503

Inventors:

Kevin K. Lee - Cambridge MA, US
Desmond R. Lim - Cambridge MA, US

Assignee:

LNL Technologies, Inc. - Cambridge MA

International Classification:

G02B006/12

US Classification:

385 14, 385 31, 385 32, 385 49, 385 42, 385 89, 385 92, 385129, 385130, 385 43, 385131, 385132, 385 27, 385 28

Abstract:

The invention features a programmable optical chip. The optical chip has a plurality of optical functions, each of which is connected to a waveguide having a core and a cladding. A photosensitive layer is disposed between at least three of the waveguides, and the photosensitive layer has a refractive index similar to that of the cladding prior to exposure to irradiation. The photosensitive layer changes refractive index upon exposure to irradiation to selectively form an optical connection between at least two of the waveguides.

US Patent:

6925226, Aug 2, 2005

Filed:

Aug 1, 2003

Appl. No.:

10/632247

Inventors:

Desmond R. Lim - Cambridge MA, US
Lionel C. Kimerling - Concord MA, US

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

G02B006/26

US Classification:

385 32, 385 4, 385 24, 385 39, 385129

Abstract:

Methods of tuning, switching or modulating, or, in general, changing the resonance of waveguide micro-resonators. Changes in the resonance can be brought about, permanently or temporarily, by changing the size of the micro-resonator with precision, by changing the local physical structure of the device or by changing the effective and group indices of refraction of the mode in the micro-resonator. Further changing the asymmetry of the index profile around a waveguide can alter the birefringence of the waveguide and allows one to control the polarization in the waveguide. This change in index profile may be used to change the polarization dependence or birefringence of the resonators.