Stuart Ellen Kramer

US Patent:

52803830, Jan 18, 1994

Filed:

Dec 2, 1992

Appl. No.:

7/894621

Inventors:

John F. Federici - Somerset NJ
Stuart A. Kramer - Fair Lawn NJ
Gerald Nykolak - Brooklyn NY

Assignee:

AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H01S 330
G02C 626

US Classification:

359341

Abstract:

A two-stage optical fiber amplifier requiring substantially reduced power comprises a pre-amplifier first-stage operating in the linear region within the small signal limits, and a post-amplifier second-stage operating in a saturated regime providing significant gain compression. The pump power for the pre-amp stage is minimized, and all of the gain compression occurs in the second stage. Minimum pump power and the corresponding amplifier fiber length needed to achieve a predetermined optimum amount of small signal gain required in a given amplifier application may be achieved in variations of the design.

US Patent:

51877597, Feb 16, 1993

Filed:

Nov 7, 1991

Appl. No.:

7/788952

Inventors:

David J. DiGiovanni - Scotch Plains NJ
Clinton R. Giles - Middletown NJ
Stuart A. Kramer - Fair Lawn NJ
Gerald Nykolak - Brooklyn NY
Herman M. Presby - Highland Park NJ
Jay R. Simpson - Fanwood NJ

Assignee:

AT&T Bell Laboratories - Murray Hill NJ

International Classification:

G01S 330
H01S 330
G02B 622

US Classification:

385 27

Abstract:

Indiscriminately exciting the modes of a multi-mode optical fiber amplifier is avoided by an optical fiber amplifier design in which the excitation of pump modes in the core of a multi-mode fiber is controlled by controlling the pump light launching. The pump light is directed substantially along the center axis of a multi-mode fiber within a predetermined launch angle. Rather than exciting all modes, only lower order modes are affected.