Richard Lee Smart

US Patent:

6421172, Jul 16, 2002

Filed:

Dec 27, 1999

Appl. No.:

09/472459

Inventors:

Felton A. Flood - Somerset NJ
Yongqian Liu - Painted Post NY
Richard G. Smart - Horseheads NY

Assignee:

Corning Incorporated - Corning NY

International Classification:

H01S 300

US Classification:

35934141, 3593371, 3593374

Abstract:

The optical amplifier includes a first gain medium having an optical host that contains a rare earth dopant and a first pump that supplies optical energy at a first wavelength into this first gain medium. The first pump operates at a pump wavelength that has a lower inversion saturation than the highest wavelength of absorption of the first gain medium. The optical amplifier further comprises a second gain medium operatively coupled to the first gain medium and a second pump that supplies optical energy into the second gain medium.

US Patent:

54064040, Apr 11, 1995

Filed:

Nov 2, 1993

Appl. No.:

8/146340

Inventors:

David J. DiGiovanni - Montclair NJ
Jonathan A. Nagel - Freehold NJ
Richard G. Smart - Naperville IL
James W. Sulhoff - Ocean NJ
John L. Zyskind - Shrewsbury NJ

Assignee:

AT&T Corp. - Murray Hill NJ

International Classification:

H04B 1000

US Classification:

359161

Abstract:

The present invention relates to a method of mitigating gain peaking in a chain of fiber amplifiers by pumping the amplifiers at a predetermined wavelength to produce gain over a specified wavelength range.

US Patent:

54305721, Jul 4, 1995

Filed:

Sep 30, 1993

Appl. No.:

8/129825

Inventors:

David J. DiGiovanni - Montclair NJ
Joseph D. Evankow - Colts Neck NJ
Jonathan A. Nagel - Freehold NJ
Richard G. Smart - Naperville IL
James W. Sulhoff - Ocean NJ
John L. Zyskind - Shrewsbury NJ

Assignee:

AT&T Corp. - Murray Hill NJ

International Classification:

G02B 626

US Classification:

359341

Abstract:

High output power, high gain, and low noise are achieved in a two-stage optical amplifier, suitable for use as a repeater for a long haul lightwave communication system, in accordance with the principles of the invention, by employing a first amplifying stage having a signal gain sufficiently small to prevent self-saturation by amplified stimulated emission (ASE) that uses counter-propagating pump light to cause maximum inversion of the first stage amplifying medium. In an illustrative embodiment of the invention, EDFAs are used in each of two amplifying stages. The length of the EDFA in the first stage is short enough to ensure nearly complete inversion of the EDFA from pump light that counter-propagates with the signal. The counter-propagating pump light allows the invention to advantageously avoid the significant noise figure penalty from the input loss associated with co-propagating pump light. And, noise figure is improved because complete inversion is achieved throughout the EDFA, and, at the input where the noise figure is most sensitive to inversion.