High average power optical fiber cladding mode stripper, methods of making and uses

Patent metadata

Field	Value
Publication number	US-2018045895-A1
Application number	US-201715788752-A
Country	US
Kind code	A1
Filing date	Oct 19, 2017
Priority date	Jun 3, 2011
Publication date	Feb 15, 2018
Grant date	—

Abstract

Nano-particle based mode strippers for removing undesirable laser energy for laser systems. Nano-particle mode strippers having matched indices of refraction to the outer cladding remove cladding light converting it into heat. There are provided fibers having evanescent mode strippers having annular outer cores and claddings.

First claim

What is claimed:

1 . A high power laser mode stripper in optical communication with an optical fiber and in thermal communication with a heat sink, the mode stripper comprising:
a. a carrier medium; b. the carrier medium being in direct physical contact and in optical contact with a cladding layer of an optical fiber; c. the carrier medium having an index of refraction and the outer cladding having an index of refraction; wherein the carrier medium index of refraction is matched to the cladding index of refraction, whereby light from the cladding will propagate into the carrier medium; d. the carrier medium holding a distribution of nano-particles, whereby the distribution of nano-particles is configured to effect the light propagated from the cladding into the carrier medium; and, e. the carrier medium is in thermal contact with a heat sink; f. whereby upon propagation of light from the cladding to the carrier medium, the nano-particles and carrier medium convert the light propagated from the cladding into heat which is transmitted by the carrier medium to the heat sink.

2 . The mode stripper of claim 1 , wherein the indices of refraction are matched to within about 5% of each other.

3 . The mode stripper of claim 1 , wherein the indices of refraction are matched to within about 2% of each other.

4 . The mode stripper of claim 1 , wherein the indices of refraction are matched to within about 1% of each other.

5 . The mode stripper of claim 1 , wherein the indices of refraction are matched to within about 0.1% of each other.

6 . The mode stripper of claim 1 , wherein the indices of refraction are the same.

7 . The mode stripper of claim 1 , wherein the carrier medium is selected from the group consisting of sodium silicate, fused silica, and spinel.

8 . The mode stripper of claim 1 , wherein the nano-particles have a D50 particle size of about 100 nm to 2000 nm.

9 . The mode stripper of claim 1 , wherein the nano-particles have a D50 particle size of about 10 nm to 2000 nm.

10 . The mode stripper of claim 1 , wherein the nano-particles are selected from the group consisting of silica, diamond, spinel, sapphire, and borosilicate glass.

11 . The mode stripper of claim 1 , wherein the effect on the light propagated from the cladding to the carrier material comprises scattering.

12 . The mode stripper of claim 1 , wherein the effect on the light propagated from the cladding to the carrier material comprises absorption.

13 . A method of forming a mode stripper on an optical fiber, the method comprising:
a. providing an outer surface of a cladding layer of an optical fiber having a core; b. applying a composition to the outer surface; c. the composition comprising a transparent liquid medium having a dispersion of nano-particles; d. solidifying the transparent liquid medium to form a solid layer of dispersed nano-particles, the solidified layer of medium having a predetermined index of refraction; and, e. placing the solid layer of dispersed nano-particles in thermal contact with a heat sink.

14 . The method of claim 13 comprising abrading the outer surface of the option fiber before applying the composition.

15 . The method of claim 13 , wherein the indices of refraction are matched to within about 5% of each other.

16 . The method of claim 13 , wherein the indices of refraction are matched to within about 1% of each other.

17 . The method of claim 1 , wherein the nano-particles have a D50 particle size of about 100 nm to 2000 nm.

18 . A high power laser mode stripper in optical communication with an optical fiber and in thermal communication with a heat sink, the mode stripper comprising:
a. a carrier medium; b. the carrier medium being in direct physical contact and in optical contact with a cladding layer of an optical fiber; c. the carrier medium having an index of refraction and the outer cladding having an index of refraction; wherein the carrier medium index of refraction is matched to the cladding index of refraction, whereby light from the cladding will propagate into the carrier medium; d. the carrier medium holding a distribution of nano-particles, whereby the distribution of nano-particles is capable of absorbing and scattering the light propagated from the cladding into the carrier medium; and, e. the carrier medium is in thermal contact with a heat sink; f. whereby the nano-particles are capable of converting the light propagated from the cladding to the carrier medium to heat which is transmitted to the heat sink.

19 . The mode stripper of claim 18 , wherein at least about 50% of the light propagated from the cladding into the carrier medium is scattered by the nano-particles.

20 . The mode stripper of claim 18 , wherein at least about 80% of the light propagated from the cladding into the carrier medium is scattered by the nano-particles.

21 . The mode stripper of claim 18 , wherein about 5% to 20% of the light propagated from the cladding into the carrier medium is absorbed by the nano-particles.

22 . The mode stripper of claim 18 , wherein at least about 90% of the light propagated from the cladding into the carrier medium is scattered by the nano-particles.

23 . The mode stripper of claim 18 , wherein the nano-particles have a particle size of about 100 nm to about 2000 nm.

24 . The mode stripper of claim 18 , wherein the nano-particles have a particle size of about 500 nm to about 1500 nm.

25 . The mode stripper of claim 18 , wherein the nano-particles have a particle size of about 2000 nm and smaller.

26 . A high power laser fiber defining a length, the fiber comprising:
a. a core, an inner cladding surrounding the core and in optical communication with the core, and an evanescent mode stripper; b. wherein the evanescent mode stripper comprises:
i. an outer annular core in optical communication with the inner cladding;
ii. an outer cladding in physical contact and optical communication with the annular core;
iii. and a mode stripping medium in optical and physical communication with the outer cladding;
c. whereby upon propagation of cladding modes the cladding modes are stripped from the fiber and converted to heat by the mode stripping medium.

27 . The fiber of claim 26 , wherein the evanescent mode stripper is at least 10% of the length of the fiber.

28 . The fiber of claim 26 , wherein the evanescent mode stripper is at least 20% of the length of the fiber.

29 . The fiber of claim 26 , wherein the mode stripper material is acrylate.

30 . The fiber of claim 26 , wherein the mode stripper material is a high temperature acrylate.

31 . The fibers of claims 26 , 27 and 28 , wherein the length is not shorter than 50 m.

32 . The fibers of claims 26 , 27 and 28 , wherein the length is not shorter than 500 m.

33 . The fibers of claims 26 , 27 and 28 , wherein the length is not shorter than 1000 m.

34 . The fibers of claims 26 , 27 and 28 wherein the length is from about 1 m to about 2 km.

35 . The fibers of claims 26 , 27 and 28 wherein the length is about 30 m to about 100 m.

36 . A laser system for use in oil field laser operations, the system comprising:
a. a high p

Assignees

• Foro Energy Inc

Inventors

• Lee Ian
• Kuznetsov Andrey
• Faircloth Brian O

Classifications

• G02B6/3813 Primary

  for transmission of high energy beam (coupling high energy sources and light guides G02B6/4296) · CPC title

• H01S3/0064

  Anti-reflection devices, e.g. optical isolaters (absorbing layers for marking or protecting purposes in laser working B23K26/50; magneto-optical non-reciprocal devices G02F1/093, G02F1/0955) · CPC title

• G02B6/14

  Mode converters · CPC title

• G02B6/4427

  Pressure resistant cables, e.g. undersea cables · CPC title

• G02B2006/4297

  having protection means, e.g. protecting humans against accidental exposure to harmful laser radiation · CPC title