ContentsFibre Laser (and Sensor)

Technologies

Lorinda Wu

CSIR National Laser Centre

2

NLC: Novel Laser Sources Group

• Conducts R&D into novel laser sources, with a focus on mid-IR.

• Developed a number of high power solid state laser sources for clients.

3

What is a Fibre Laser?

LaserFibre

Fibre Guided Laser

Laser

Fibre Laser

Laser

Traditional LaserLaser Beam

4

n1

n2

n1 < n2

Optical Fibre Properties

Properties

• Total internal reflection light guide

• Light scattering and absorption

Types of fibres

• Single mode (9/125m) vs multimode

• Step index vs specialty fibres

• Core doped with rare-earth material to lase at

particular wavelength

5

Fibre Lasers > Other Industrial Lasers

Compact Rugged

High Efficiency

Cost EffectiveFL

CO2

6 Zervas & Codemard, IEEE JSTQE (2014)

Comparison of Laser Technologies

7

Fibre Lasers have better beam quality

Zervas & Codemard, IEEE JSTQE (2014)

BPP = Beam Parameter Product (beam quality)

8

Fibre Laser Building Blocks

9

Maximum Power Achieved to Date

Zervas & Codemard, IEEE JSTQE (2014)

Power Evolution of Yb-doped Fibre Lasers

NLC R&D in“Eye Safe” region

Commercial SystemsIPG – 10 kW @ 1 mIPG – 200W @ 2 m

10

NLC: Establishing R&D Activities in Fibre Lasers

Mid-IR Fibre Lasers

Fibre Components (MFA, tapers,

combiners)

Tm-doped

CW Polarised Pulsed Tuneable MOPA

Ho-doped

• Develop characterisation tools for fibre components and fibre lasers.

We have established expertise in mid-IR high power

lasers, using commercial fibre lasers as pump (energy)

sources

11

NLC Research: Mid-IR Fibre Lasers

• Initial results:

– >70 W output (Tm-doped fibre laser)

– >2 W output (Ho-doped fibre laser)

• Passive fibre components for 2m fibre lasers

are not readily available.

• Commercial fibres, sourced from overseas.

Limited in design, restricted in applications.

• Collaborator on Ho-doped fibres.

LD

12

Fibre Laser Applications

Deliver beam directly to location of interest.

• Industrial materials processing

– Project Aeroswift uses IPG 5 kW 1m fibre laser for additive manufacturing.

• Instrumentation and sensors

• Medical and aesthetic

• Automotive

• Consumer products

• Microelectronics

• Aerospace and defence

14

Current Fibre Laser Challenges:

Towards even higher power

• Nonlinear effects

– Stimulated Brillouin scattering

– Stimulated Raman scattering

– Self-phase modulation

• Photonic crystal fibres/ Larger core

• Spatial beam combining

• Coherent beam combining

• Spectral beam combining

15

30 kW Fibre Laser Weapon System

• Spectrally beam combined single mode Yb-doped fibre laser

• Laser weapon system ATHENA (Advanced Test High Energy Asset)

prototype

• Developed by Lockheed Martin

• Target over 1 mile away (March 2015)

16

Source: Industrial Laser Solutions (1/1/2013)

Global Laser Market

0

200

400

600

800

1000

1200

CO2 Solid State Fibre Other

An

nu

al R

eve

nu

e

($ M

illio

ns)

2011

2012

2013(F)

Market Leaders in Fibre Lasers:IPGRofinTrumpf …?

17

Laser Market Share per Industry

0

50

100

150

200

250

300

CO2 Solid state Fibre

An

nu

al R

eve

nu

e (

$ m

illio

ns)

Laser Marking/Engraving

0

100

200

300

400

500

600

700

800

CO2 Solid state Fibre Other

An

nu

al R

eve

nu

e (

$ m

illio

ns)

Micro Materials Processing (< 1kW)

0

100

200

300

400

500

600

700

800

CO2 Solid state Fibre Other

An

nu

al R

eve

nu

e (

$ m

illio

ns)

Macro Materials Processing (> 1kW)

2012

2013

2014 (F)

Source: http://www.industrial-lasers.com/articles/print/volume-29/issue-1/features/fiber-laser-revenues-boost-the-2013-laser-market.html

18

Other Fibre Optic Technologies

• Optical Communications (E.g. signal amplifiers)

• Physical sensors

– Pressure/acoustic, rotation, displacement, bending/torsion, temp

erature, current/voltage

• Chemical and biological sensors

• Many applications in

health, agriculture, environment, security and defence

19

Fibre Sensor Applications

Distributed

motion sensors

Distributed

temperature, strain or

pressure sensors

Gyroscopes

20

Optical Fibre Sensors: Fibre Bragg Gratings

• Discrete sensor

• Advantages:

– Immune to EM interference

– Work in harsh environments

– Corrosion resistant

– Reliable >25 years

– Small/compact (can be embedded)

– Multiplex (time, wavelength) large number of sensors onto a single

fibre.

University of Johannesburg

21

How Does Fibre Bragg Grating Sensor Work?

Chemical and biological sensors –coat FBG with selected material.

22

Distributed Fibre Sensors

• Fibre is the sensor !

• Rayleigh backscattering

– influenced by acoustic waves in fibre environment

• Brillouin backscattering

– frequency shift temperature, strain

• Optical pulse sent down fibre, time of flight of

backscattered light monitored distance.

• Real time monitoring

• Tens of kms with metre resolution

23

Communications

• NMMU – High speed

optical

networks, clock

timing (SKA)

• NMISA – optical

frequency systems

• Wits – modal

multiplexing in free

space & fibre

Fibre Sensors

• UJ – Fibre Bragg

gratings for sensor

applications

Fibre Optics R&D in South Africa

Fibre Lasers

• CSIR-NLC – mid-

infrared high power

fibre lasers

24

Conclusions and Future Outlook

• Fibre lasers

• Cost effective, energy efficient

• Fibre competing with solid-state and CO2 lasers.

• Applications in many manufacturing industries: metals & plastics processing

• Technology in mid-IR not yet mature, need further R&D.

• Fibre Sensors

• Physical sensor technology fairly mature and gradually coming into commercial use.

• Significant R&D still taking place, esp. chemical and biological sensors.

Thank you for

your attention!

Lorinda Wu (lwu@csir.co.za)