Cladding light stripper and method of manufacturing

• US 10,090,631 B2
• Filed: 12/29/2016
• Issued: 10/02/2018
• Est. Priority Date: 01/28/2013
• Status: Active Grant

• Current Assignee: Lumentum Operations, LLC (Lumentum Holdings Inc.)
• Original Assignee: Lumentum Operations, LLC (Lumentum Holdings Inc.)
• Inventors: Hou, Kai-Chung, Kliner, Dahv, Muendel, Martin H., Weston, Jeremy
• Primary Examiner(s): Bolda, Eric L
• Application Number:
  US15/393,887
• Publication Number:
  US 20170110845A1
• Time in Patent Office: 642 Days
• CPC Class Codes: B23K 26/0622 by shaping pulses
• CPC Class Codes: B23K 26/0626 Energy control of the laser beam B23K26/0622 takes precedence
• CPC Class Codes: B23K 26/36 Removing material B23K26/55, B23K26/57 take precedence
• CPC Class Codes: B29D 11/00663 Production of light guides
• CPC Class Codes: G02B 6/02066 Gratings having a surface relief structure, e.g. repetitive variation in diameter of core or cladding
• CPC Class Codes: G02B 6/14 Mode converters
• CPC Class Codes: G02B 6/264 with optical elements between opposed fibre ends which perform a function other than beam splitting having lens focusing means G02B6/32; utilising prism or grating G02B6/34
• CPC Class Codes: G02B 6/2852 using tapping light guides arranged sidewardly, e.g. in a non-parallel relationship with respect to the bus light guides (light extraction or launching through cladding, with or without surface discontinuities, bent structures)
• CPC Class Codes: H01S 3/06729 Peculiar transverse fibre profile
• CPC Class Codes: H01S 3/06733 Fibre having more than one cladding
• CPC Class Codes: H01S 3/094007 Cladding pumping, i.e. pump light propagating in a clad surrounding the active core
• CPC Class Codes: H01S 3/0941 of a laser diode

Abstract

A cladding stripper includes a plurality of transversal notches or grooves in the outer surface of an exposed inner cladding of a double clad optical fiber. Position and orientation of the notches can be selected to even out cladding light release along the cladding light stripper, enabling more even temperature distributions due to released cladding light. The notches on the optical fiber can be made with a laser ablation system.

Claims

1. A cladding light stripper comprising:

an optical fiber having a core for guiding signal light and a cladding surrounding the core,

the optical fiber including a stripped portion, thereby forming an exposed section of a surface of the cladding,

the exposed section including a plurality of notches, disposed along the optical fiber, having a pitch that varies along a length of the exposed section.

2. The cladding light stripper of claim 1, wherein cladding light is at least one of:

reflected from a respective side surface of each notch of the plurality of notches, or

refracted from the respective side surface of each notch of the plurality of notches.

3. The cladding light stripper of claim 1, wherein the pitch gradually varies along the length of the exposed section.

4. The cladding light stripper of claim 1, wherein the pitch varies between 1 notch/cm and 1000 notches/cm.

5. The cladding light stripper of claim 1, wherein respective depths of the plurality of notches gradually vary.

6. The cladding light stripper of claim 1, wherein a depth of a first notch, of the plurality of notches, is different than a depth of a second notch of the plurality of notches.

7. The cladding light stripper of claim 1, wherein the plurality of notches are spaced along the length and around a circumference of the exposed section.

8. The cladding light stripper of claim 1, wherein the exposed section comprises a curved section having a bend radius.

9. The cladding light stripper of claim 1, wherein the optical fiber is a double-clad optical fiber.

10. The cladding light stripper of claim 1, wherein

the cladding is an inner cladding, and

the cladding light stripper further includes an outer cladding surrounding the inner cladding.

11. An optical fiber amplifier comprising:

an optical fiber having a core for guiding signal light and a cladding surrounding the core,

the optical fiber including a stripped portion, thereby forming an exposed section of a surface of the cladding,

the exposed section including a plurality of notches, disposed along the optical fiber, having a pitch that varies along a length of the exposed section;

an amplifier optical fiber portion coupled to the optical fiber at a first end of the amplifier optical fiber portion, and

a pump diode, optically coupled to a second, opposing end of the amplifier optical fiber portion, for providing pump light for propagation from the second, opposing end to the first end of the amplifier optical fiber portion.

12. The optical fiber amplifier of claim 11, wherein cladding light is at least one of:

reflected from a respective side surface of each notch of the plurality of notches, or

refracted from the respective side surface of each notch of the plurality of notches.

13. The optical fiber amplifier of claim 11, wherein the pitch varies along the length of the exposed section.

14. The optical fiber amplifier of claim 11, wherein the pump light is provided from the pump diode to the amplifier optical fiber portion using at least one lens and a dichroic mirror.

15. The optical fiber amplifier of claim 11, wherein at least one of:

respective depths of the plurality of notches gradually vary,

the plurality of notches are spaced along the length and around a circumference of the exposed section, or

the exposed section comprises a curved section having a bend radius.

16. An optical fiber comprising:

a core for guiding signal light;

a cladding surrounding the core,

the optical fiber including a stripped portion, thereby forming an exposed section of a surface of the cladding,

the exposed section including a plurality of notches, disposed along the optical fiber, having a pitch that varies along a length of the exposed section.

17. The optical fiber of claim 16, wherein cladding light is at least one of:

reflected from a respective side surface of each notch of the plurality of notches, or refracted from the respective side surface of each notch of the plurality of notches.

18. The optical fiber of claim 16, wherein the pitch varies between 1 notch/cm and 1000 notches/cm.

19. The optical fiber of claim 16, wherein at least one of:

respective depths of the plurality of notches gradually vary,

the plurality of notches are spaced along the length and around a circumference of the exposed section, or

the exposed section comprises a curved section having a bend radius.

20. The optical fiber of claim 16, wherein respective depths of the plurality of notches are between 20 micrometers to 80 micrometers deep.