Optical fiber configurations for transmission of laser energy over great distances

• US 8,879,876 B2
• Filed: 10/18/2013
• Issued: 11/04/2014
• Est. Priority Date: 07/21/2010
• Status: Active Grant

• Current Assignee: Foro Energy, Inc.
• Original Assignee: Foro Energy, Inc.
• Inventors: Rinzler, Charles C., Zediker, Mark S.
• Primary Examiner(s): PENG, CHARLIE YU
• Application Number:
  US14/057,567
• Publication Number:
  US 20140248025A1
• Time in Patent Office: 382 Days
• Field of Search: 385/104, 385/111, 294/28
• US Class Current: 385/104
• CPC Class Codes: G02B 6/4402 with one single optical waveguide G02B6/4429, G02B6/4439, G02B6/4479 take precedence
• CPC Class Codes: G02B 6/4413 Helical structure
• CPC Class Codes: G02B 6/4415 Cables for special applications G02B6/4429, G02B6/4439, G02B6/4479 take precedence
• CPC Class Codes: G02B 6/443 Protective covering
• CPC Class Codes: G02B 6/4458 Coiled, e.g. extensible helix
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

There are provided optical fiber configurations that provide for the delivery of laser energy, and in particular, the transmission and delivery of high power laser energy over great distances. These configurations further are hardened to protect the optical fibers from the stresses and conditions of an intended application. The configurations provide means for determining the additional fiber length (AFL) need to obtain the benefits of such additional fiber, while avoiding bending losses.

Claims

1. A method of using a line structure for transmitting laser energy, the method comprising:

a. providing a line structure,

b. the line structure comprising;

i. an optical fiber comprising a first end, a second end, a length (L_F) defined between the first and second optical fiber ends, and a fiber core, wherein the optical fiber has an outer radius (R_F), a coefficient of thermal expansion (CTE_F), and a minimum bend radius (R_Fmin);

ii. an outer protective member around the optical fiber, the outer protective member comprising a first end, a second end, and a length (L_OPM) defined between the first and second outer protective member ends at ambient temperature and with no mechanical strain, wherein the outer protective member has an inner radius (R_OPM), a coefficient of thermal expansion (CTE_OPM), and the R_OPM is greater than the R_F;

iii. the first and second ends of the outer protective member and the first and second ends of the optical fiber are substantially coterminous;

iv. the line structure has a predetermined temperature range for use (Δ

T), a predetermined mechanical strain (ε

), and when the optical fiber is wound into a coil it has a predetermined inner radius of coil (R_coil);

v. wherein the L_F is greater than the L_OPM, so that L_P−

L_OPM=AFL (additional fiber length);

vi. the optical fiber taking a helical non-following path within the outer protective member;

vii. the AFL is equal to or between at least one of;

an AFL[L] from Formulas 2 and 4 as defined in Applicants'"'"' Specification;

or an AFL[%] from Formulas 1 and 3 as defined in Applicants'"'"' Specification;

c. deploying the line structure;

d. transmitting laser energy through the optical fiber; and

,

e. recovering the line structure.

2. The method of claim 1, wherein the line structure is deployed down a borehole.

3. The method of claim 1, wherein the line structure is deployed from a spool.

4. The method of claim 1, wherein the line structure is recovered to a spool.

5. A method of transmitting laser energy over a line structure, the method comprising:

a. providing a line structure,

b. the line structure comprising;

i. an optical fiber, the fiber comprising a first end, a second end, a length (L_F) defined between the first and second optical fiber ends, and a fiber core, wherein the optical fiber has an outer radius (R_F), a coefficient of thermal expansion (CTE_F), and a minimum bend radius (R_Fmin);

ii. an outer protective member around the optical fiber, the outer protective member comprising a first end, a second end, and a length (L_OPM) between the first and second outer protective member ends at ambient temperature and with no mechanical strain, wherein the outer protective member has an inner radius (R_OPM), a coefficient of thermal expansion (CTE_OPM), and the R_OPM is greater than the R_F;

iii. the first and second ends of the outer protective member and the first and second ends of the optical fiber are substantially coterminous;

iv. wherein the line structure has a predetermined temperature range (Δ

T), a predetermined mechanical strain (ε

), and a predetermined inner radius of coil (R_coil);

v. wherein the L_F is greater than the L_OPM, so that L_F−

L_OPM=AFL (additional fiber length);

vi. the optical fiber taking a sinusoidal non-following path within the outer protective member;

vii. the AFL is equal to or between at least one of;

an AFL[L] from Formulas 9 and 11 as defined in Applicants'"'"' Specification;

or an AFL[%] from Formulas 8 and 10 as defined in Applicants'"'"' Specification;

c. deploying the line structure;

d. transmitting laser energy through the optical fiber; and

,

e. recovering the line structure.

6. The method of claim 5, wherein:

R_OPM is at least about 1.0 mm;

R_F is at least about 100 μ

m;

the Δ

T is at least about 50°

C.;

ε

is at least about 0.01%;

CTE_F is at least about 0.5*10<sup>−

6</sup> (1/C);

CTE_OPM, is at least about 7*10<sup>−

6</sup> (1/C);

L_OPM is at least about 1 km;

R_Fmin is at least about 5 cm; and

, R_coil is at least about 10 cm;

wherein the configuration is capable of transmitting a laser beam having at least 1 kW of power, without substantial power loss.

7. The method of claim 5, wherein:

R_OPM is at least about 1.0 mm;

R_F is at least about 100 μ

m;

the Δ

T is at least about 50°

C.;

ε

is at least about 0.01%;

CTE_F is at least about 0.5*10<sup>−

6</sup> (1/C);

CTE_OPM is at least about 7*10<sup>−

6</sup> (1/C);

L_OPM is at least about 0.5 km;

R_Fmin is at least about 5 cm; and

, R_coil is at least about 10 cm;

wherein the configuration is capable of transmitting a high power laser beam over great distances without substantial power loss.

8. The method of claim 5, wherein the fiber core has a radius greater than about 75 μ

m.

9. The method of claim 5, wherein the fiber core has a radius of greater than about 300 μ

m.

10. A method of transmitting laser energy over an optical fiber configuration, the method comprising:

a. providing a line structure,

b. the line structure comprising;

i. an optical fiber, a portion of the optical fiber comprising a first end, a second end, a length (L_F) defined between the first and second optical fiber ends, and a fiber core, wherein the optical fiber has an outer radius (R_F), a coefficient of thermal expansion (CTE_F), and a minimum bend radius (R_Fmin);

ii. an outer protective member around the optical fiber portion, a portion of the outer protective member comprising a first end, a second end, and a length (L_OPM) defined between the first and second outer protective member ends at ambient temperature and with no mechanical strain, wherein the outer protective member has an inner radius (R_OPM), a coefficient of thermal expansion (CTE_OPM), and the R_OPM is greater than the R_F;

iii. the first and second ends of the outer protective member and the first and second ends of the optical fiber are substantially coterminous;

iv. the optical fiber configuration has a predetermined temperature range (Δ

T), a predetermined mechanical strain (ε

), and a predetermined inner radius of coil (R_coil);

v. wherein the L_F is greater than the L_OPM, so that L_F−

L_OPM=AFL (additional fiber length);

vi. the optical fiber taking a helical non-following path within the outer protective member; and

,

vii. the AFL is equal to or between at least one of;

an AFL[L] from Formulas 2 and 4 as defined in Applicants'"'"' Specification;

or an AFL[%] from Formulas 1 and 3 as defined in Applicants'"'"' Specification;

viii. whereby, the optical fiber configuration is capable of transmitting at least about 1 kW of laser energy over great distances without substantial bending losses;

c. deploying the line structure;

d. transmitting laser energy through the optical fiber; and

,

e. recovering the line structure.

11. A method of transmitting laser energy over an optical fiber configuration, the method comprising:

a. providing a line structure,

b. the line structure comprising;

i. an optical fiber, a portion of the fiber comprising a first end, a second end, a length (L_F) defined between the first and second optical fiber ends, and a fiber core, wherein the optical fiber has an outer radius (R_F), a coefficient of thermal expansion (CTE_F), and a minimum bend radius (R_Fmin);

ii. an outer protective member around the optical fiber portion, a portion of the outer protective member comprising a first end, a second end, and a length (L_OPM) between the first and second outer protective member ends at ambient temperature and with no mechanical strain, wherein the outer protective member has an inner radius (R_OPM), a coefficient of thermal expansion (CTE_OPM), and the R_OPM is greater than the R_F;

iii. the first and second ends of the outer protective member and the first and second ends of the optical fiber are substantially coterminous;

iv. wherein the optical fiber configuration has a predetermined temperature range (Δ

T), a predetermined mechanical strain (ε

), and a predetermined inner radius of coil (R_coil);

v. wherein the L_F is greater than the L_OPM, so that L_F−

L_OPM=AFL (additional fiber length);

vi. the optical fiber taking a sinusoidal non-following path within the outer protective member;

vii. the AFL is equal to or between at least one of;

an AFL[L] from Formulas 9 and 11 as defined in Applicants'"'"' Specification;

or an AFL[%] from Formulas 8 and 10 as defined in Applicants'"'"' Specification;

viii. whereby, the optical fiber configuration is capable of transmitting at least about 1 kW of laser energy over great distances without substantial bending losses;

b. deploying the line structure;

c. transmitting laser energy through the optical fiber; and

,

d. recovering the line structure.