Thomas W Koch

US Patent:

6359915, Mar 19, 2002

Filed:

Sep 23, 1999

Appl. No.:

09/401901

Inventors:

Thomas L. Koch - Holmdel NJ
Xing Pan - Morganville NJ

Assignee:

Agere Systems - Orlando FL

International Classification:

H01S 313

US Classification:

372 2902, 372 29011, 372 29016, 372 3802, 372 96, 372102

Abstract:

A stabilized single-longitudinal-mode laser where stabilization is performed through a pair of Bragg reflector mirrors slightly displaced in wavelength to either side of the longitudinal mode selected for operation. Transmitted signals through each Bragg reflector are detected and used in an electrical servo loop to control the relative positions of the longitudinal mode selected for operation and the peak wavelengths of the two Bragg reflector mirrors.

US Patent:

6392751, May 21, 2002

Filed:

Nov 28, 2000

Appl. No.:

09/723959

Inventors:

Thomas L. Koch - Holmdel NJ
Donald R. Scifres - San Jose CA

Assignee:

JDS Uniphase Corporation - San Jose CA

International Classification:

G01B 902

US Classification:

356478, 356477, 385 8, 385 14

Abstract:

An improved interferometric modulator permits the reduction in size of optical transmitters. In one embodiment, the optical modulator includes amplifiers or attentuators as phase modulators. In another embodiment, two outputs from a combiner are fed to the modulator, thus avoiding the requirement for an input splitter in the modulator. Light passing through the modulator may be both phase-shifted and amplified or attenuated by optical regulator sections located in the modulator. In another embodiment, the transmitter is included as a multiple-wavelength optical communications source, where individual current sources are provided to actuate a number of light sources feeding into the combiner, a processor controls the operation of each light source, and a modulator driver receives a data input signal to be encoded on the output of the source. By combining a number of modulators, a gray scale modulator may be fabricated for producing a gray scale output, rather than a conventional binary level output.

US Patent:

6490044, Dec 3, 2002

Filed:

Sep 17, 1998

Appl. No.:

09/154929

Inventors:

Thomas L. Koch - Holmdel NJ
Donald R. Scifres - San Jose CA

Assignee:

JDS Uniphase Corporation - San Jose CA

International Classification:

G02B 2700

US Classification:

356478, 359577

Abstract:

An improved interferometric modulator permits the reduction in size of optical transmitters. In one embodiment, the optical modulator includes amplifiers or attentuators as phase modulators. In another embodiment, two outputs from a combiner are fed to the modulator, thus avoiding the requirement for an input splitter in the modulator. Light passing through the modulator may be both phase-shifted and amplified or attenuated by optical regulator sections located in the modulator. In another embodiment, the transmitter is included as a multiple-wavelength optical communications source, where individual current sources are provided to actuate a number of light sources feeding into the combiner, a processor controls the operation of each light source, and a modulator driver receives a data input signal to be encoded on the output of the source. By combining a number of modulators, a gray scale modulator may be fabricated for producing a gray scale output, rather than a conventional binary level output.

US Patent:

47156724, Dec 29, 1987

Filed:

Jan 6, 1986

Appl. No.:

6/816199

Inventors:

Michel A. Duguay - Fair Haven NJ
Thomas L. Koch - Middletown NJ
Yasuo Kokubun - Yokohama, JP
Loren N. Pfeiffer - Morristown NJ

Assignee:

American Telephone and Telegraph Company - Murray Hill NJ

International Classification:

G02B 610

US Classification:

350 9612

Abstract:

A planar silicon dioxide waveguide with low loss for the TE mode has been built on a silicon wafer by separating the waveguide from the substrate with a relatively thin layer of polycrystalline silicon and a layer of silicon dioxide having a combined thickness less than that of the waveguide. The separating layers provide a high antiresonant reflectivity which is operative over a broad range of wavelengths.

US Patent:

47642467, Aug 16, 1988

Filed:

Aug 20, 1987

Appl. No.:

7/087550

Inventors:

Thomas J. Bridges - Holmdel NJ
Ernest G. Burkhardt - Wall NJ
Larry A. Coldren - Santa Barbara CA
Thomas L. Koch - Middletown NJ

Assignee:

American Telephone and Telegraph Company, AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H01L 21306
B44C 122
C03C 1500
C03C 2506

US Classification:

156643

Abstract:

Epitaxial regrowth by vapor phase epitaxy of controlled composition semiconductor material in and around undercut regions of a processed heterostructure wafer permits formation of a ridge waveguide capable of active or passive operation. Subsequent material selective and crystallographically preferential etching is employed to form mirror facets on each end of the ridge waveguide.

US Patent:

56638248, Sep 2, 1997

Filed:

Nov 2, 1993

Appl. No.:

8/146653

Inventors:

Thomas L. Koch - Holmdel NJ
Fumio Koyama - Sagamihara, JP
Kang-Yih Liou - Holmdel NJ

Assignee:

Lucent Technologies Inc. - Murray Hill NJ

International Classification:

H04B 1004

US Classification:

359184

Abstract:

An apparatus and technique for providing isolation for a signal source utilizing two or more modulators is described. In particular, the apparatus generates a timed sequence of "open gates" that are synchronized to the data signal which permit transmission in a forward direction, and which attenuate a reverse direction signal. Another embodiment attenuates primarily reflected light signals by utilizing a passive waveguide and a modulator. The passive waveguide provides a propagation delay such that signals reflected from its end facet are attenuated by the modulator. The apparatus is suitable for use as an isolator for a light source in a high-speed optical fiber data transmission system.

US Patent:

49320327, Jun 5, 1990

Filed:

Aug 3, 1989

Appl. No.:

7/389087

Inventors:

Thomas L. Koch - Holmdel NJ
Uziel Koren - Fair Haven NJ

Assignee:

AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H01S 319

US Classification:

372 45

Abstract:

Adiabatic mode control and structural reproducibility are achieved by a tapered semiconductor waveguide structure wherein semiconductor guiding layers are interleaved with stop-etch layers and each successive guiding layer extends further along the propagation axis of the waveguide than the guiding layer immediately adjacent thereabove to create a staircase-like core or guiding structure. Cladding regions of appropriate semiconductor material having a lower index of refraction than the tapered core structure may be added to completely surround the tapered guiding structure. The profile of the tapered structure is realizable as any desired staircase-like shape such as linear, parabolic, exponential or the like. Additional layers of higher index of refraction semiconductor material may be included in the cladding region to permit additional beam shaping of the expanded spatial mode propagating along the tapered waveguide.

US Patent:

47456078, May 17, 1988

Filed:

Oct 8, 1986

Appl. No.:

6/916498

Inventors:

Thomas L. Koch - Middletown NJ

Assignee:

American Telephone and Telegraph Company, AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H01S 319

US Classification:

372 45

Abstract:

A grating in the upper reflecting layer (103 or 203) of an antiresonant reflecting optical waveguide is used to extract energy of a selected wavelength from the waveguiding layer (102 or 202) into the reflecting layer. In one embodiment the reflecting layer (103) is designed as a gain medium which is pumped in the region of a grating (120) and optically terminated at each end of the device such that the embodiment serves as a laser having a long cavity provided by the waveguiding layer (102) with the gain provided in the short grating region. In a second embodiment the reflecting layer (203) in the region of a grating (211) has an opposite conductivity dopant from that of the waveguiding layer (202) such that the device in this region may be backbiased to serve as a wavelength selective photodetector. By placing two wavelength photodetectors in tandem with gratings (211 and 212)of different pitches a wavelength demultiplexing photodetector is provided.