Compensation of polarization mode dispersion of a grating written in an optical fiber

• US 20020122625A1
• Filed: 05/07/2001
• Published: 09/05/2002
• Est. Priority Date: 05/11/2000
• Status: Active Grant

• Current Assignee: II-VI Incorporated
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Sansonetti, Pierre, Riant, Isabelle, Berthelot, Laurent
• Granted Patent: US 6,535,669 B2
• Time in Patent Office: Days
• US Class Current: 385/37
• CPC Class Codes: G02B 6/02109 having polarization sensitive features, e.g. reduced photo-induced birefringence
• CPC Class Codes: G02B 6/02138 based on illuminating a phase mask
• CPC Class Codes: G02B 6/022 using mechanical stress, e.g. tuning by compression or elongation, special geometrical shapes such as "dog-bone" or taper G02B6/02204 takes precedence; optical modulation using photo-elastic effect G02F1/0131
• CPC Class Codes: G02B 6/278 Controlling polarisation mode dispersion [PMD], e.g. PMD compensation or emulation PMD minimised transmission systems H04B10/2569
• CPC Class Codes: G02B 6/29317 Light guides of the optical fibre type

Abstract

The invention relates to polarization mode dispersion; writing index variations in a grating written in an optical fiber generates polarization mode dispersion. The invention proposes to compensate this polarization mode dispersion by mechanical curvature of the fiber. The invention provides a simple method of compensating polarization mode dispersion effectively and improving the performance of a grating written in a fiber; it applies in particular to Bragg gratings.

Claims

1. An optical fiber incorporating a written grating, the optical fiber having a curvature in a plane substantially perpendicular to the axis of the birefringence induced by writing the grating.

2. The optical fiber of claim 1, wherein the angle between said plane and the axis of the birefringence induced by writing the grating is in the range 65°

and 115°

.

3. The optical fiber of claim 1, wherein the curvature extends at least into the area in which the grating is written.

4. The optical fiber of claim 1, wherein the curvature is constant and has a value in the range 5 m⁻

1 to 10 m<sup>−

1</sup>.

5. The optical fiber of claim 1, wherein the written grating is a Bragg grating.

6. An optical component including an optical fiber according to claim 1.

7. A chromatic dispersion compensator including at least one fiber according to claim 1.