Won Jin Choi

US Patent:

6804421, Oct 12, 2004

Filed:

Jan 25, 2002

Appl. No.:

10/056929

Inventors:

Aaron Bond - Orefield PA
Ram Jambunathan - Allentown PA
Won Jin Choi - Allentown PA

Assignee:

T-Networks, Inc. - Allentown PA

International Classification:

G02F 1035

US Classification:

385 2, 385 20, 359344

Abstract:

A monolithic single pass expanded beam mode active optical device includes: a substrate; a waveguide layer coupled to the top surface of the substrate; a semiconductor layer coupled to the waveguide layer; first and second electrodes for receiving an electric signal coupled to the substrate and the semiconductor layer, respectively. The waveguide layer includes a plurality of sublayers, forming a quantum well structure, which is responsive to the electric signal. The waveguide layer has three sections, two expansion/contraction sections and an active section, which extends between and adjacent to the two expansion/contraction sections. The thickness of at least one of the plurality of sublayers varies within the expansion/contraction portions of the quantum well structure. Possible interactions of the active region with the light include: absorption in the case of an electro-absorptive modulator and optical gain.

US Patent:

6862376, Mar 1, 2005

Filed:

Jul 21, 2004

Appl. No.:

10/895699

Inventors:

Aaron Bond - Orefield PA, US
Ram Jambunathan - Allentown PA, US
Won Jin Choi - Allentown PA, US

Assignee:

T-Networks, Inc. - Allentown PA

International Classification:

G02F001/01
G02F001/035
G02B006/10
H01L021/00

US Classification:

385 1, 385 2, 385131, 438 31

Abstract:

A method of manufacturing a monolithic expanded beam mode electroabsorption modulator including a waveguide layer with a two expansion/contraction sections and an electroabsorption section arranged along a longitudinal axis. At least one patterned growth retarding layer is formed on the top surface of a substrate. The waveguide layer is formed on a portion of the top surface of the substrate by selective area growth and has an index of refraction different from the substrate. An electroabsorption portion of the waveguide layer has a thickness which is greater than thicknesses in its other portions. The semiconductor layer is formed on the waveguide layer and includes an index of refraction different from the waveguide. The waveguide and semiconductor layers are defined and etched to form the expansion/contraction and electroabsorption sections of the waveguide layer. Electrical contacts are formed, one electrically coupled to the substrate and another electrically coupled to the semiconductor layer.