Controlled phase delay between beams for writing bragg gratings

US7018745B2 · kind B2 · utility

Assignee

• The University of Sydney · AU

Inventors

• Dmitrii Stepanov · Sydney, AU
• Mark Sceats · Sydney, AU

Key dates

• Filing date: Jan 9, 2003
• Grant date: Mar 28, 2006
• Expiry date: Mar 2, 2023

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S430/146
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A method of writing an extended grating structure in a photosensitive waveguide comprising the steps of utilizing at least two overlapping beams of light to form an interference pattern, moving the waveguide through said overlapping beams, simultaneously controlling a relative phase delay between the beams utilising a phase modulator, thereby controlling the positions of maxima within said interference pattern to move at approximately the same velocity as the photosensitive waveguide, wherein the phase modulator does not comprise a mechanical means for effecting the phase modulation, and modifying the relative phase delay between the beams during the writing of the grating structure, whereby a deliberate detuning of the velocity of the positions of maxima within said interference pattern and the velocity of the photosensitive waveguide is utilized to vary a period of the written grating structure in the photosensitive waveguide.