System comprising Er-doped optical fiber

US5058976A · kind A · utility

Assignee

• AT&T Bell Laboratories · US

Inventors

• David J. DiGiovanni · Mountain Lakes, US
• Kenneth L. Walker · New Providence, US

Key dates

• Filing date: Aug 3, 1990
• Grant date: Oct 22, 1991
• Expiry date: Aug 3, 2010

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01S3/1693
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

The inventive optical fiber communication system comprises Si-based amplifier fiber whose core comprises Ge, Al, and Er. The amplifier fiber has an effective index difference (.DELTA.n) greater than 0.03, an effective core diameter a less than 3.5 .mu.m, a maximum Al concentration in the core of at least 6 mole %, a mode field diameter at the pump wavelength that is less than 5 .mu.m, a V-number at the pump wavelength in the range 1.4-2.0, a cut-off wavelength less than 1.4 .mu.m, and an Er distribution whose effective diameter is less than that of the Ge distribution. The fiber has advantageous properties including low amplification threshold and noise. Disclosed is also a method of making optical fiber that can be used to produce fiber having characteristics (e.g., .DELTA.n>0.03, high Al concentration) not generally obtainable with prior art methods. In a particular embodiment the method comprises a partial collapse of a tubular preform prior to completion of core material deposition, completion of core material deposition, and final collapse.