Temperature compensated optical device

US6621957B1 · kind B1 · utility

Assignee

• CiDRA Corporation · US

Inventors

• James M. Sullivan · Manchester, US
• Timothy J. Bailey · Longmeadow, US
• Robert N. Brucato · Waterbury, US
• Thomas Engel · Munich, DE
• Mark R. Fernald · Enfield, US
• Richard T. Jones · Hamden, US
• Alan D. Kersey · Burke, US
• Trevor MacDougall · South Dartmouth, US
• Matthew B. Miller · Glastonbury, US
• Martin A. Putnam · Cheshire, US
• Paul E. Sanders · Madison, US
• James S. Sirkis · Wallingford, US

Key dates

• Filing date: Oct 30, 2000
• Grant date: Sep 16, 2003
• Expiry date: Nov 11, 2020

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01S3/1028
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A temperature compensated optical device includes a compression-tuned glass element 10 having a Bragg grating 12 therein, a compensating material spacer 26 and an end cap 28 all held within an outer shell 30. The element 10, end cap 28 and shell 30 are made of a material having a low coefficient of thermal expansion (CTE), e.g., silica, quartz, etc. and the spacer 26 is made of a material having a higher CTE, e.g., metal, Pyrex®, ceramic, etc. The material and length L5 of the spacer 26 is selected to offset the upward grating wavelength shift due to temperature. As temperature rises, the spacer 26 expands faster than the silica structure causing a compressive strain to be exerted on the element 10, which shifts the wavelength of the grating 12 down to balance the intrinsic temperature induces wavelength shift up. As a result, the grating 12 wavelength is substantially unchanged over a wide temperature range. The element 10 includes either an optical fiber having at least one Bragg grating 12 impressed therein encased within and fused to at least a portion of a glass capillary tube or a large diameter waveguide (or cane) with a grating 12 having a core 11 and a wide cladding, w…