Optical waveguide device

• US 6,160,944 A
• Filed: 01/30/1998
• Issued: 12/12/2000
• Est. Priority Date: 04/28/1995
• Status: Expired due to Term

• Current Assignee: SPI Lasers UK Limited (TRUMPF SE + Co. KG)
• Original Assignee: University of Southampton
• Inventors: Dong, Liang, Payne, David Neil, Cruz, Jose Luis
• Primary Examiner(s): Scott, Jr., Leon
• Application Number:
  US08/945,475
• Time in Patent Office: 1,047 Days
• Field of Search: 385/129, 385/142, 385/144
• US Class Current: 385/129
• CPC Class Codes: G02B 2006/02157 Grating written during drawing of the fibre
• CPC Class Codes: G02B 6/021 characterised by the core or cladding or coating, e.g. materials, radial refractive index profiles, cladding shape
• CPC Class Codes: G02B 6/02133 using beam interference
• CPC Class Codes: G02B 6/0219 based on composition of fibre materials
• CPC Class Codes: G02B 6/124 Geodesic lenses or integrated gratings

Abstract

Tin-doped photosensitive optical glass is disclosed, together with applications of the glass in fabricating waveguides and waveguide devices such as Bragg gratings.

Claims

1. An optical waveguide device comprising:

an optical waveguide formed at least in part of photosensitive optical glass; and

a refractive index variation optically impressed on the photosensitive optical glass of the waveguide by exposure of regions of the photosensitive optical glass to a refractive index-varying optical radiation,

characterised in that the photosensitive optical glass is doped with tin as a photosensitising dopant.

2. A device according to claim 1, the device having an optically-induced periodic refractive index variation to form a waveguide grating.

3. A device according to claim 2, in which the period of the refractive index variation is non-uniform.

4. A device according to claim 2, in which the refractive index variation has a uniform period in the range of 0.1 μ

m to 1 μ

m.

5. A device according to claim 2, in which the refractive index variation has a uniform period in the range of 1 μ

m and 1 cm.

6. A device according to claim 1, in which the photosensitive optical glass is photosensitive to ultraviolet radiation.

7. A device according to claim 1, in which the waveguide is a planar waveguide.

8. A device according to claim 1, in which the waveguide is an optical fibre waveguide having at least one light-guiding core surrounded by a cladding material.

9. A device according to claim 8, in which the core is formed of tin-doped glass and the cladding is formed of silica glass.

10. A device according to claim 8, in which the core and the cladding are formed of tin-doped glass.

11. A device according to claim 1, in which the tin-doped glass is tin-doped silica glass.

12. A device according to claim 1, in which the tin-doped glass contains up to 30 mole-percent of tin.

13. A device according to claim 1, in which the tin-doped glass is co-doped with one or more co-dopants selected from the group consisting of:

up to 40 mole-percent phosphorus;

up to 40 mole-percent boron; and

up to 30 mole-percent of germanium.

14. A device according to claim 1, in which the tin-doped glass has up to 15 mole-percent tin, and is co-doped with one or more co-dopants selected from the group consisting of:

up to 20 mole-percent phosphorus;

up to 20 mole-percent boron; and

up to 20 mole-percent germanium.

15. A device according to claim 1, in which the tin-doped glass is co-doped with one or more co-dopants selected from the group consisting of:

up to 40 mole-percent germanium; and

up to 30 mole-percent boron.

16. A device according to claim 1, in which the tin-doped glass has up to 20 mole-percent tin, and is co-doped with one or more co-dopants selected from the group consisting of:

between 2 and 30 mole-percent germanium; and

up to 25 mole-percent boron.

17. A device according to claim 1, in which the tin-doped glass contains up to 15 mole-percent of tin.

18. A device according to claim 1, in which the tin-doped optical glass is co-doped with one or more co-dopants selected from the group consisting of:

aluminium, gallium, indium, arsenic, antimony, titanium, tantalum, zirconium, niobium, fluorine and lead.

19. A method of fabricating an optical waveguide, the method comprising the steps of:

providing a photosensitive optical glass which has been doped with tin as a photosensitizing dopant; and

exposing regions of the tin-doped photosensitive optical glass to refractive index change-inducing optical radiation, the exposed regions providing a light-guiding core of raised refractive index within the tin-doped photosensitive optical glass.

20. A method according to claim 19, in which the tin-doped optical glass is formed as a layer sandwiched between layers of non-photosensitive cladding glass.

21. A process for increasing the sensitivity of optical glass to light-induced refractive index variation, the process comprising the steps of:

doping the optical glass with tin for increasing the sensitivity of the optical glass to light-induced refractive index variation; and

exposing regions of the tin-doped photosensitive optical glass to refractive index-varying optical radiation to vary the refractive index of the exposed regions of the tin-doped photosensitive optical glass.