Optical hollow-core delivery fiber and hollow-endcap termination and associated method

• US 7,379,648 B1
• Filed: 05/27/2006
• Issued: 05/27/2008
• Est. Priority Date: 07/29/2005
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Aculight Corp. (Martin Marietta Corporation)
• Original Assignee: Aculight Corporation (Martin Marietta Corporation)
• Inventors: Di Teodoro, Fabio, Brooks, Christopher D.
• Primary Examiner(s): Hughes; Deandra M
• Application Number:
  US11/420,752
• Time in Patent Office: 731 Days
• Field of Search: 385/126
• US Class Current: 385/126
• CPC Class Codes: C03B 37/10 Non-chemical treatment surface treatment of fibres or filaments made from glass, minerals or slags C03C25/00
• CPC Class Codes: G02B 6/02328 Hollow or gas filled core
• CPC Class Codes: G02B 6/02347 Longitudinal structures arranged to form a regular periodic lattice, e.g. triangular, square, honeycomb unit cell repeated throughout cladding
• CPC Class Codes: G02B 6/02376 Longitudinal variation along fibre axis direction, e.g. tapered holes
• CPC Class Codes: G02B 6/02385 Comprising liquid, e.g. fluid filled holes
• CPC Class Codes: G02B 6/3826 characterised by form or shape
• CPC Class Codes: G02B 6/3853 Lens inside the ferrule lensed connectors G02B6/32
• CPC Class Codes: H01S 3/005 Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B
• CPC Class Codes: H01S 3/0064 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 Class Codes: H01S 3/0078 Frequency filtering
• CPC Class Codes: H01S 3/06704 Housings; Packages
• CPC Class Codes: H01S 3/06708 Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering optical fibres as passive waveguides G02B6/02
• CPC Class Codes: H01S 3/06729 Peculiar transverse fibre profile
• CPC Class Codes: H01S 3/06741 Photonic crystal fibre, i.e. the fibre having a photonic bandgap
• CPC Class Codes: H01S 3/06745 Tapering of the fibre, core or active region
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/06758 Tandem amplifiers
• CPC Class Codes: H01S 3/094007 Cladding pumping, i.e. pump light propagating in a clad surrounding the active core

Abstract

A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range). By using multiple small waveguides in parallel, large amounts of energy can be passed through a laser, but with better control such that the aforementioned problems can be reduced. An additional advantage is that the polarization of the light can be maintained better than by using a single fiber core.

Claims

1. An apparatus comprising:

a hollow-core photonic-crystal fiber (HCPCF), wherein a first end of the HCPCF is cleaved to form an end facet, wherein the first end is connected into a first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds.

4. The apparatus of claim 1, further comprising a second closed-end connector attached to a second end of the HCPCF, wherein the second closed-end connector includes an end-mounted focusing lens window and a hollow cavity between the end facet of the HCPCF and the end window.

2. An apparatus comprising:

a hollow-core photonic-crystal fiber (HCPCF), wherein a first end of the HCPCF is cleaved to form an end facet, wherein the first end is connected into a first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds, wherein the first closed-end connector includes a slanted end window and a hollow cavity between the end facet of the HCPCF and the end window.

3. An apparatus comprising:

a hollow-core photonic-crystal fiber (HCPCF) wherein a first end of the HCPCF is cleaved to form an end facet, wherein the first end is connected into a first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds, wherein the first closed-end connector includes an end-mounted collimating lens window and a hollow cavity between the end facet of the HCPCF and the end window.

5. An apparatus comprising:

a hollow-core photonic-crystal fiber (HCPCF), wherein a first end of the HCPCF is cleaved to form an end facet, wherein the first end is connected into a first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds, wherein the first closed-end connector includes a hollow cavity that is laser welded around the first end of the HCPCF.

6. An apparatus comprising:

a hollow-core photonic-crystal fiber (HCPCF), wherein a first end of the HCPCF is cleaved to form an end facet wherein the first end is connected into a first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds, wherein the first closed-end connector includes a hollow cavity that attached around the first end of the HCPCF by heat shrinking.

7. An apparatus comprising:

a hollow-core photonic-crystal fiber (HCPCF), wherein a first end of the HCPCF is cleaved to form an end facet, wherein the first end is connected into a first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds, wherein the first closed-end connector includes a hollow cavity that soldered around the first end of the HCPCF.

8. An apparatus comprising:

a hollow-core photonic-crystal fiber (HCPCF), wherein a first end of the HCPCF is cleaved to form an end facet, wherein the first end is connected into a first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds, wherein the first closed-end connector includes a hollow glass ferrule that is laser welded around the first end of the HCPCF, and an end window laser welded to the ferrule.

9. An apparatus comprising:

a hollow-core photonic-crystal fiber (HCPCF), wherein a first end of the HCPCF is cleaved to form an end facet, wherein the first end is connected into a first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds; and

a photonic-crystal amplifier device (PCAD) having a core diameter of at least 100 microns and configured to amplify dispersively stretched pulses, wherein the PCAD is optically coupled to deliver high-power optical pulses to the HCPCF, and wherein the HCPCF has dispersive properties tailored to recompress the amplified stretched pulses.

10. An apparatus comprising:

a hollow-core photonic-crystal fiber (HCPCF) having a first end of the HCPCF cleaved to form an end facet, and a first closed-end connector having an optically-transmissive port; and

means for connecting the first end into the first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds.

11. The apparatus of claim 10, wherein the first closed-end connector includes a slanted end window and a hollow cavity between the end facet of the HCPCF and the end window.

12. The apparatus of claim 10, wherein the first closed-end connector includes an end-mounted collimating lens window and a hollow cavity between the end facet of the HCPCF and the end window.

13. The apparatus of claim 10, further comprising

a second closed-end connector, wherein the second closed-end connector includes an end-mounted focusing lens window and a hollow cavity between the end facet of the HCPCF and the end window;

and

means for attaching the second closed-end connector to a second end of the HCPCF.

14. The apparatus of claim 10, wherein the first closed-end connector includes a hollow cavity, wherein the means for connecting further comprises

laser welded means for connecting the first closed-end connector around the first end of the HCPCF.

15. A method comprising:

providing a hollow-core photonic-crystal fiber (HCPCF) having a first end of the HCPCF cleaved to form an end facet, and a first closed-end connector having an optically-transmissive port; and

connecting the first end into the first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds.

16. A method comprising:

providing a hollow-core photonic-crystal fiber (HCPCF) having a first end of the HCPCF cleaved to form an end facet, and a first closed-end connector having an optically-transmissive port; and

connecting the first end into the first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds, wherein the first closed-end connector includes a slanted end window and a hollow cavity between the end facet of the HCPCF and the end window.

17. A method comprising:

providing a hollow-core photonic-crystal fiber (HCPCF) having a first end of the HCPCF cleaved to form an end facet, and a first closed-end connector having an optically-transmissive port; and

connecting the first end into the first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds, wherein the first closed-end connector includes an end-mounted collimating lens window and a hollow cavity between the end facet of the HCPCF and the end window.

18. A method comprising:

providing a hollow-core photonic-crystal fiber (HCPCF) having a first end of the HCPCF cleaved to form an end facet, and a first closed-end connector having an optically-transmissive port; and

connecting the first end into the first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds,

providing a second closed-end connector, wherein the second closed-end connector includes an end-mounted focusing lens window and a hollow cavity between the end facet of the HCPCF and the end window; and

attaching the second closed-end connector to a second end of the HCPCF.

19. A method comprising:

providing a hollow-core photonic-crystal fiber (HCPCF) having a first end of the HCPCF cleaved to form an end facet, and a first closed-end connector having an optically-transmissive port; and

connecting the first end into the first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds, wherein the first closed-end connector includes a hollow cavity, wherein the connecting further comprises laser welding the first closed-end connector around the first end of the HCPCF.

20. A method comprising:

providing a hollow-core photonic-crystal fiber (HCPCF) having a first end of the HCPCF cleaved to form an end facet, and a first closed-end connector having an optically-transmissive port; and

connecting the first end into the first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds, wherein the first closed-end connector includes a hollow cavity, wherein the connecting further comprises attaching the first closed-end connector around the first end of the HCPCF by heat shrinking.

21. A method comprising:

providing a hollow-core photonic-crystal fiber (HCPCF) having a first end of the HCPCF cleaved to form an end facet, and a first closed-end connector having an optically-transmissive port; and

connecting the first end into the first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds, wherein the first closed-end connector includes a hollow cavity, wherein the connecting further comprises soldering the first closed-end connector around the first end of the HCPCF.

22. A method comprising:

providing a hollow-core photonic-crystal fiber (HCPCF) having a first end of the HCPCF cleaved to form an end facet, and a first closed-end connector having an optically-transmissive port; and

connecting the first end into the first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds, wherein the first closed-end connector includes a hollow glass ferrule;

laser welding the first closed-end connector around the first end of the HCPCF; and

laser welding an end window to the ferrule.

23. A method comprising:

providing a hollow-core photonic-crystal fiber (HCPCF) having a first end of the HCPCF cleaved to form an end facet, and a first closed-end connector having an optically-transmissive port; and

connecting the first end into the first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds

providing a photonic-crystal amplifier device (PCAD) having a core diameter of at least 100 microns;

configuring the PCAD to amplify dispersively stretched pulses;

optically coupling the PCAD to deliver high-power optical pulses to the HCPCF; and

configuring the HCPCF to have dispersive properties tailored to recompress the amplified stretched pulses.

24. An apparatus comprising:

a hollow-core photonic-crystal fiber (HCPCF) having a first end of the HCPCF cleaved to form an end facet, and a first closed-end connector having an optically-transmissive port; and

means for connecting the first end into the first closed-end connector attached to the first end of the HCPCF without the aid of epoxy adhesives or other organic compounds;

a photonic-crystal amplifier device (PCAD) having a core diameter of at least 100 microns;

means for configuring the PCAD to amplify dispersively stretched pulses;

means for optically coupling the PCAD to deliver high-power optical pulses to the HCPCF; and

means for configuring the HCPCF to have dispersive properties tailored to recompress the amplified stretched pulses.