DEVICE FOR COUPLING PUMP LIGHT INTO A FIBER AND METHOD FOR PRODUCING A DEVICE OF THIS TYPE

• US 20160218479A1
• Filed: 08/26/2014
• Published: 07/28/2016
• Est. Priority Date: 08/27/2013
• Status: Active Grant

• Current Assignee: Rosenberger Hochfrequenztechnik GmbH & Company KG (Rosenberger Technology (Kunshan) Co., Ltd.)
• Original Assignee: Rosenberger Hochfrequenztechnik GmbH & Company KG (Rosenberger Technology (Kunshan) Co., Ltd.)
• Inventors: Weigand, Benjamin, Theobald, Christian, L'huillier, Johannes Albert, Wurster, Clemens
• Granted Patent: US 9,620,923 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02B 6/262 Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: H01S 3/06704 Housings; Packages
• CPC Class Codes: H01S 3/094019 Side pumped fibre, whereby pump light is coupled laterally into the fibre via an optical component like a prism, or a grating, or via V-groove coupling
• CPC Class Codes: H01S 3/094049 Guiding of the pump light
• CPC Class Codes: H01S 3/094053 Fibre coupled pump, e.g. delivering pump light using a fibre or a fibre bundle

Abstract

A device for laterally coupling pump light into a fiber. A fiber runs in a longitudinal direction, having an optically active medium to be pumped and a lateral wall running approximately in the longitudinal direction, and at least one light coupler, at least some part of which runs parallel to the fiber along the lateral wall. The light coupler is an optical waveguide which is optically coupled to the fiber such that pump light propagating in the optical waveguide can be coupled into the fiber via the lateral wall. The efficiency of the pump light coupling is improved by a plurality of windings of the fiber being located alternately with waveguides on a substrate. The pump light can be coupled into all waveguides simultaneously, for example by a prism.

Claims

1. A device for laterally coupling pump light into a fiber comprising the fiber which runs in a longitudinal direction (L) and which has an optically active medium to be pumped, with a lateral wall running approximately in the longitudinal direction (L) and with at least one light coupler, at least some part of which runs parallel to the fiber along the lateral wall, wherein the light coupler is an optical waveguide which is optically coupled to the fiber such that pump light propagating in the optical waveguide can be coupled into the fiber via the lateral wall, in particular by a mode crosstalk, or by overlap of evanescent fields, wherein the fiber has two or more pump sections, each running in the longitudinal direction (L) and arranged next to one another, between which an optical waveguide is in each case arranged, such that the optical waveguides are formed in a plate-formed wafer, wherein the device includes a coupling part with a flat contact surface for coupling pump light into the optical waveguide which lies against a flat lateral surface of the optical waveguide.

2. The device of claim 1, wherein the optical waveguide is a waveguide with at least one flat outer boundary surface such as a ridge waveguide or an optical fiber with flat.

3. The device of claim 1, wherein the lateral wall of the fiber lies in contact with an outer boundary surface of the optical waveguide and/or an intermediate space between the lateral wall of the fiber and an outer boundary surface of the optical waveguide facing the lateral wall is filled with a refractive-index-matched translucent medium such as a polymer-containing medium.

4. The device of claim 1, wherein in order to increase the efficiency of coupling, an outer boundary surface of the optical waveguide facing the lateral wall of the fiber is structured, displaying an amplitude modulation.

5. The device of claim 1, including a refractive index modulation in the fiber and/or in the optical waveguide in order to increase the efficiency of coupling into the fiber.

6. The device of claim 1, including two optical waveguides arranged on opposite sides of the fiber, in the form of ridge waveguides.

7. The device of claim 1 wherein the pump sections of the fiber and the optical waveguides alternate periodically in a direction (Q) transverse, in particular roughly perpendicular, to the longitudinal direction.

8. The device of claim 1 wherein the fiber is arranged in windings, wherein each winding contains a pump section.

9. The device of claim 1 wherein the fiber includes a core with the optically active medium and a cladding surrounding the core with the lateral wall, the refractive index of which is matched to the refractive index of the optical waveguide.

10. The device of claim 1 wherein the coupling part is a coupling prism.

11. The device of claim 1, wherein the coupling part covers two or more optical waveguides arranged next to one another in a transverse direction.

12. The device of claim 1, wherein two or more optical waveguides are fixed next to one another on a common substrate, wherein the transition between the optical waveguides and the substrate is configured such that total reflection occurs within the interior of the optical waveguide at the transition.

16. The device of claim 2, wherein the lateral wall of the fiber lies in contact with an outer boundary surface of the optical waveguide and/or an intermediate space between the lateral wall of the fiber and an outer boundary surface of the optical waveguide facing the lateral wall is filled with a refractive-index-matched translucent medium such as SmartGel®

.

17. The device of claim 16, wherein in order to increase the efficiency of coupling, an outer boundary surface of the optical waveguide facing the lateral wall of the fiber is structured, displaying an amplitude modulation.

18. The device of claim 17, including a refractive index modulation in the fiber and/or in the optical waveguide in order to increase the efficiency of coupling into the fiber.

19. The device of claim 17, including two optical waveguides arranged on opposite sides of the fiber, in the form of ridge waveguides.

20. The device of claim 19 wherein the pump sections of the fiber and the optical waveguides alternate periodically in a direction (Q) transverse, in particular roughly perpendicular, to the longitudinal direction.

21. The device of claim 10, wherein the coupling part covers two or more optical waveguides arranged next to one another in a transverse direction.

13. A method for manufacturing a device for laterally coupling pump light into a fiber comprising the fiber which runs in a longitudinal direction (L) and which has an optically active medium to be pumped, with a lateral wall running approximately in the longitudinal direction (L) and with at least one light coupler, at least some part of which runs parallel to the fiber along the lateral wall, wherein the light coupler is an optical waveguide which is optically coupled to the fiber such that pump light propagating in the optical waveguide can be coupled into the fiber via the lateral wall, in particular by a mode crosstalk, or by overlap of evanescent fields, wherein the fiber has two or more pump sections, each running in the longitudinal direction (L) and arranged next to one another, between which an optical waveguide is in each case arranged, such that the optical waveguides are formed in a plate-formed wafer, wherein the device includes a coupling part with a flat contact surface for coupling pump light into the optical waveguide which lies against a flat lateral surface of the optical waveguide, said method including optical waveguides running next to one another in a plate-formed wafer, and in which a fiber with an optically active core is then laid, in a form-locking manner, in the spaces formed between the optical waveguides, and a coupling part with a flat contact surface for coupling pump light into the optical waveguide is laid against a flat lateral surface of the at least one optical waveguide.

14. The method of claim 13, wherein the optical waveguides are created in the wafer through laser ablation, etching and/or mechanical machining processes such as milling or sawing.

15. The method of claim 13, wherein a refractive-index-matched, gel-like medium is introduced into the spaces between the optical waveguides before laying the fiber.