FIRST developed in the 1970s, thin, flexible, and transparent optical fiber revolutionized the telecommunications industry, acting as the structure for carrying electromagnetic waves from point to point. Because of its large bandwidth and immunity from electromagnetic interference, optical fiber has largely replaced copper wire for transmitting data over long distances—across the country, for example. An optical fiber can also be made into a laser by mixing rare-earth ions into the fiber’s glass structure and pumping those ions with a separate laser diode, such as the diodes that generate the light in a laser pointer. Fiber lasers can take this concept a step further, combining the power of many inexpensive laser diodes into a single coherent beam. The fibers are especially well suited for scaling up high-power, continuous-wave lasers that emit a steady stream of photons. Commercial laser systems have reached average powers of 10 kilowatts, high enough to cut and machine metal parts for the automotive and heavy-equipment industries. Because fiber lasers are compact and reliable and their beams can be focused to extremely small, diffraction-limited spots, they have also found a niche in scientific applications. In this area, however, their performance is limited. They work well for tasks in which energy is spread evenly over time—the metaphorical equivalent of slowly pushing a tack into a board with your thumb—but not for applications that require energy bursts—akin to hitting a nail with a hammer. That’s because the fiber’s small cross section lets it amplify pulses to levels that damage the fiber itself. Unlike the bulk fibers produced by the telecommunication industry, which are completely solid and circularly symmetric, Livermore researchers have developed intricately detailed ribbon-like photonic crystal fibers made designed to handle some serious power coursing through them. Read more: http://1.usa.gov/1lBJILd

1. LLNL-PRES-773886
This work was performed under the auspices of the
U.S. Department of Energy by Lawrence Livermore
National Laboratory under contract DE-AC52-07NA27344.
Lawrence Livermore National Security, LLC
Dr. JayW. Dawson, FiberTechnologies Group Leader

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 Fibers
• Diffraction limited beams
• Robust, flexible transport
• Operate in extreme environments
and insensitive to electro-magnetic
interference
 Fiber Lasers
• Low maintenance & high reliability
• Efficient (>30% wall-plug)
• High average powers (kW)

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Telecom Flexible Delivery for
Industrial Machining
High Power Laser Sources
Distributed Sensors
Short-pulse surgery
laser delivery
Sensors for Oil and Gas
HighVoltage Current Sensors
These are examples of a wide array of potential applications in
flexible light transport, sensors and components for laser systems.

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Cross section: 125 µm O.D. Very low losses attainable
Strong and Flexible 50% transmission over 30km

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Diffraction
Photonic crystal fiber
Refraction
Conventional fiber

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P = 0.065 W P = 1.1 W P = 2.4 W
Optical Near Field
Optical Far Field
250 µm
200 µm
10 µm X 120 µm
Yb3+ Slab
Waveguide
Secondary
Waveguide for
Diode Pump Light
0
1
2
3
4
5
6
0 5 10 15 20
OutputPower,W
Coupled Pump Power, W
5 W at 44% optical efficiency
Example: investigation of
rectangular core fiber lasers
for improved power scaling

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Proposed Design Calculated Waveguide Modes

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Computer Model Manufacturing Design

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Raw Material
Draw to ~1mm
rods and tubes
Stack to Fiber Design
Final Preform in
Furnace
Fiber Production
Draw
Tower

10. Lawrence Livermore National Laboratory
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11. Lawrence Livermore National Laboratory
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215 µm
Passive
Ribbon Fiber
200 µm
250 µm
Yb3+ Ribbon Fiber
250 µm
UV Rad Hard
Qualification Fiber
Hollow Core Cane
(preform)
Negative Curvature
Core
for mid-IR

12. Lawrence Livermore National Laboratory
LLNL-PRES-773886
 Hollow core waveguides for high power transport
 Short wavelength fiber lasers (<1µm)
 UV radiation hard fibers for NIF
 Three SBIR collaborations
• 2 defense, 1 medical
• Joint proposal development opportunities
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hollow single mode
R&D 100 Award
 Discerned fiber limits1
 Pioneered ribbon fiber2
 Launched high-order modes3
(R&D 100 Award, 2013)
 Power scaling in ribbon lasers4
 Designed new type of fiber5,6,7
 Developing a 1,000+ core
fiber for the National Ignition Facility
1. J. Dawson et al, Opt. Exp. 16 13240-13266 (2008).
2. D. Drachenberg et al, Opt. Exp. 21 11257-11269 (2013).
3. A. Sridharan et al, Opt. Exp. 20 28792-28800 (2012).
4. D. Drachenberg et al, submitted to Opt. Express (2013).
5. M. Messerly et al, Opt. Exp. 21 12683-12698 (2013).
6. M. Messerly et al, Optics Letters 18 3329-3332 (2013).
7. P. Pax et al, submitted to Optics Letters (2013).

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 We have the flexibility and motivation to work on “out
of the box” designs that commercial vendors may be
less interested in pursuing in early stage development
 We bring a wide array of expertise to new fiber
development and are very open about the
manufacturing process and limitations
 Do you have a problem where a novel optical fiber can
help?
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Catherine Elizondo
elizondo1@llnl.gov