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Electronically-Steerable, Coherent Laser Arrays REALLY Small, Lightweight, High Power Lasers for DoD Applications Electronically-Steerable, Coherent Laser Arrays REALLY Small, Lightweight, High Power Lasers for DoD Applications MTO Symposium Joseph Mangano, PM March 7, 2007 MTO Symposium Joseph Mangano, PM March 7, 2007

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Page 1: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Electronically-Steerable, Coherent Laser ArraysREALLY Small, Lightweight, High Power Lasers for DoD Applications

Electronically-Steerable, Coherent Laser ArraysREALLY Small, Lightweight, High Power Lasers for DoD Applications

MTO SymposiumJoseph Mangano, PM

March 7, 2007

MTO SymposiumJoseph Mangano, PM

March 7, 2007

Page 2: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Report Documentation Page Form ApprovedOMB No. 0704-0188

Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering andmaintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information,including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, ArlingtonVA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if itdoes not display a currently valid OMB control number.

1. REPORT DATE 07 MAR 2007

2. REPORT TYPE N/A

3. DATES COVERED -

4. TITLE AND SUBTITLE Electronically-Steerable, Coherent Laser Arrays REALLY Small,Lightweight, High Power Lasers for Do DApplications

5a. CONTRACT NUMBER

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S) 5d. PROJECT NUMBER

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5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) DARPA

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11. SPONSOR/MONITOR’S REPORT NUMBER(S)

12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release, distribution unlimited

13. SUPPLEMENTARY NOTES DARPA Microsystems Technology Symposium held in San Jose, California on March 5-7, 2007.Presentations, The original document contains color images.

14. ABSTRACT

15. SUBJECT TERMS

16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT

UU

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19a. NAME OFRESPONSIBLE PERSON

a. REPORT unclassified

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Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18

Page 3: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Solid-StateLaser

Amplifier

Diode-Pumped, Solid-State Laser Systems

θDL(M2 = 1)

Divergence Angle = θ = M2 θDL

θLaser Diode

Array

Prime Power, Pprime

ηLDA ηSSL Atmospheric Transmission– Turbulence (including aero-optics)– Absorption (molecular/aerosol)

TargetIrradiance(watts/cm2)

AdaptiveOptics

Power Delivery Efficiency ~ ηLDA ηSSL ηBDM4

Challenges– Power Scaling– Efficiency– Beam Quality– Size and Weight– Lifetime/Reliability– Electronically-steered, Conformal,

Adaptive, Optical Phased Arrays

Solid-StateLaser

Amplifier

Beam Director

(Diameter D)

Beam Director

(Diameter D)

ηBD

Technologies:– Electronically-Steered, Optical Phased Arrays

driven by:– Fiber Laser Amplifiers (APPLE)

or directly by:– Coherent Laser Diode Arrays (COCHISE)

Challenge: Electronically-Steered 100 kW Laser System at 2 kg per kilowatt

Page 4: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

APPLE Laser Beam Directors Adaptive Photonic Phase-Locked Elements

APPLE Laser Beam Directors Adaptive Photonic Phase-Locked Elements

All-Electronic Beam Steering with 45o Field-of-Regard

Power and Aperture Size Scaling through Coherent Beam Combining of Multiple Sub-apertures (2.5 - 5 cm dimension)

Conformal to Most Military Platforms– replaces aerodynamically-challenged turret-mounted beam directors

Near-Diffraction-Limited Beam Quality, Corrected for:– atmospheric turbulence – aero-optic effects

APPLE Beam Director Technology can provide:

Fast, Electronically-Steered, Optical Phased Array adaptable to essentially all DoD Laser Applications

− ro ~ 5 mm/ BWatm ~ 1 kHz− ro ~ 5 cm / BWatm ~ 10 kHz

Page 5: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

4

APPLEAdaptive Photonic Phase-Locked Elements

Lasercom Links Multi-target Search and TrackTarget ID

Laser Countermeasures

Laser Weapon Laser Sensing

Multiple, Conformal, Electronically-Steered SubaperturesIndependently Targeted or Coherently Combined into a Single Beam

Page 6: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Illuminator-Laser

Power-in-the-Bucket Metric

Controller(Global SPGD)

Phase-Lock

Control Loop

Phase-Locked,CompensatedSub-apertures

Seed-Laser

LiNbO3Phase, Intensity& Polarization

Controllers

Fiber Pre-Amplifier

High-PowerFiber AmplifierReceiver

Adaptive Optic Control Loop(tip-tilt, LC HEX 127)

APPLE ConceptAPPLE Concept

Target

Atmospheric Turbulence

Page 7: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Assembled APPLE SubapertureAssembled APPLE Subaperture

Adaptive Optic

Beam Expanding Telescope

100W Fiber Lase Feed

PZT Actuatorfor Tip-Tilt

Zone Fill OPAs

Zone Select OPAs

BraggGratings

100 W Fiber Laser Feed

Challenge: Coherent Array of APPLE Subapertures with Fast Adaptive Optics

Electronic Beam Steering

Page 8: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

100 Coherently-Combined Apertures (10 x 10 Array)Need High Power Fiber Laser Amplifiers– 2 kW – Single Transverse Mode– Single Polarization– < λ/20 Phase Noise – No SBS/SRS - Narrowline

These 2 kW Fiber Laser Amplifiers do not exist– 200 watts Commercially Available

Weapon Concepts Require Single-Mode,Narrowline, Kilowatt-Class Fiber LasersWeapon Concepts Require Single-Mode,Narrowline, Kilowatt-Class Fiber Lasers

50 cm

200 kW Phased Array

APPLEArray

Element

5 cm

Fiber LaserAmplifier

Narrowline FiberLaser Oscillator

Challenge: Scale these Fiber Amplifiersto 2 kW and Beyond

Page 9: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Why Coherent Diode Arrays?– Electrical Efficiency

– Thin Disk Lasers (HELLADS) 15%– Fiber Lasers 25-30%– Coherent Laser Diode Arrays 30-50%

Three Approaches:

– Talbot Cavity – Spatially-Coupled Oscillators in Supermode– Phase-Locked Loops driven from a common seed beam– Coherent Combining with SPGD Algorithm as in APPLE

IncreasingRisk

Coherent, High PowerLaser Diode Arrays

Page 10: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Challenge: Coherently Combine Kilowatt Laser Diode Arrays

Challenge: Coherently Combine Kilowatt Laser Diode Arrays

Remove Multi-Mode, UnphaseableRogue Emitters in 10s of nsec

SlabConfining Layer

Slab-Coupled Optical Waveguide Laser(SCOWL)

SlabConfining Layer

Coherent Output Beam

::

N-elementDiode Array

TalbotCavity

MaxReflector

Partial Reflector

w

dzT/2 = 2 d 2/λ

N-elementDiode Array

TalbotCavity

MaxReflector

Partial Reflector

w

dzT/2 = 2 d 2/λ

MaxReflector

Partial Reflector

w

dzT/2 = 2 d 2/λ

Partial Reflector

w

ddzT/2 = 2 d 2/λ

Partial Reflector

zT/2 = 2 d 2/λ ~ 2 cm

Talbot Cavity

1 cmw

d

N-element Single -ModeDiode Array

VBG

::

N-elementDiode Array

TalbotCavity

MaxReflector

Partial Reflector

w

dzT/2 = 2 d 2/λ

N-elementDiode Array

TalbotCavity

MaxReflector

Partial Reflector

w

dzT/2 = 2 d 2/λ

MaxReflector

Partial Reflector

w

dzT/2 = 2 d 2/λ

Partial Reflector

w

ddzT/2 = 2 d 2/λ

Partial Reflector

zT/2 = 2 d 2/λ ~ 2 cm

Talbot Cavity

1 cmw

d

N-element Single -ModeDiode Array

VBG

Partial Reflector

zT/2 = 2 d 2/λ ~ 2 cm

Talbot Cavity

1 cmw

d

N-element Single -ModeDiode Array

VBG

Talbot Cavity - Laser Diode Phased Array

Indium bump bondsIndium bondSCOWL Wafer Carrier

Common Heat Sink

SCOWL Array

SiCMOS Driver Circuit

~ 0.3 mm

SCOWL Wafer Carrier

12 mm

Common Heat Sink

SCOWL Array

SiCMOS Driver Circuit

~ 3 mm Side View

Individually drive Each Emitter in the Bar

LightOut

Diffraction-Limited Bar1 wattSingle ModeUltra-low Noise

N-element Single-ModeDiode Array

Page 11: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Drive each Emitter in SCOWL BarIndependently

Drive each Emitter in SCOWL BarIndependently

Independent Drivers for Each Emitter in a 10-Emitter Bar

Challenge: CMOS Drivers Conformally CoupledDirectly to the Diode Bar for Current Sharing and Phase Control

12

10

8

6

4

2

020151050

Current (A)C

W O

utpu

t Pow

er (W

)

980-nm COCHISE ArrayIQE-OMVPE-36, Wafer #5, Bar #2, Array #12100 µm pitch, 10 elements, ind. addr.All 10 elements on Facet Coatings R=95%/0%External Mirror R=4%, 15 µm from facetT = 5° C11/22/06

6 µm

Device 5, 0.9 A, no mirror

12

10

8

6

4

2

020151050

Current (A)C

W O

utpu

t Pow

er (W

)

980-nm COCHISE ArrayIQE-OMVPE-36, Wafer #5, Bar #2, Array #12100 µm pitch, 10 elements, ind. addr.All 10 elements on Facet Coatings R=95%/0%External Mirror R=4%, 15 µm from facetT = 5° C11/22/06

6 µm

Device 5, 0.9 A, no mirror

Page 12: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Vertically-Coupled Large Area (VECLA) LaserVertically-Coupled Large Area (VECLA) Laser

PerformanceVery low optical internal loss (<0.2 cm-1)

Very low electrical resistance, but not too low

Very low thermal resistance (~2oC/watt-mm)

Design FeaturesLow modal overlap to doped layers (<0.02)

Highly doped cladding layers (~1018 cm-3)

Thin top cladding layer (~0.05µm)

Large optical mode (~4 x 15 µm2)

Challenge: 10 watt, low noise, single-mode emitters at 50% Efficiency

Page 13: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

APPLE Sub-aperture driven bya Coherent Laser Diode Array

SPGDAlgorithm

TARGETSCOWLArray

THERMALMANAGEMENT

PRIMEPOWER

DIODEARRAYSDIODE

ARRAYSDIODE

ARRAYSTHERMAL

MANAGEMENT

PRIMEPOWER

Potential: 100 kW Laser Systems at 2 kilograms per kilowatt!

APPLE Sub-aperture driven by a Fiber Laser Amplifier

CalibratingDetector

Array

Overall Electrical Efficiency ~ 30-50% !Liquid Crystal, Fast, Ultra-Wide-Angle Electronic Steer

SPGDAlgorithm

FIBER LASER

TARGET

Liquid CrystalAdaptive Optic

Liquid Crystal, Fast, Ultra-Wide-Angle Electronic Steer

LiNbO3Phase Shifter

FIBER OSCILLATOR

VBG

Page 14: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Additional Challengesand Areas of Interest

Additional Challengesand Areas of Interest

Laser Diode Technology – for pumping Thin Disk Lasers• Increase SHEDS Diode Bar Power to ≥ 100 watts/bar-cm

– Efficiency ≥ 70%– Lifetime > 1000 hours– 1 cm bar with 1.5 mm pitch– Wavelength ~ 808nm (Nd:YLF or Nd:ceramic YAG Pump)

• Thermal Resistance from Junction to Heat Sink is the limiting factor

Fiber Laser Technology – 100 kW • Explore Ultimate Fiber Amplifier Array Scaling Limits

– Single-Mode (M2 < 1.5)– Single-Polarization

• Pump Diode Brightness is the limiting factor

Page 15: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Some ofMy Current Program Responsibilities

Some ofMy Current Program Responsibilities

Existing Programs:– APPLE – Conformal Laser Beam Director – COCHISE – Coherent Combining of Laser Diodes

ADHELS Single-Mode Laser Diode Development Laser Diode Reliability and Lifetime

– SHEDS – Laser Diode Efficiency

– Ultrabeam – X-ray Lasers

– Nanowriter – E-Beam, Direct-Write, Maskless Lithography Tool

– IM-VAC (DSO) – Compact CT Imaging Technology for Battlefield Use

Posters

Briefed Today

….so see Dr. John Zolper, Director of MTO now!!!Get Recruited as a New MTO Program Manager

Page 16: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Back ups

Page 17: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

APPLET ComponentsAPPLET Components

Tip/Tilt Compensator

(HEX 127)

Tip/Tilt Compensator

Fast Beam Steering Element Adaptive Optics Element

LiNO3 Electric Field Controller

• Intensity

• Phase

• Polarization

APPLET

SPGD Algorithmimplemented on FPGA

Fiber Laser Amplifier

Challenge: – 10x Faster Adaptive

Optic Elements

Page 18: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Phase-Locked Looparound a SCOWL Amplifier

Phase-Locked Looparound a SCOWL Amplifier

0 100 200 300 4005806006206406606807007207400.0

0.1

0.2

0.3

0.4

0.5

0.6

SCO

WA

cur

rent

(mA

)Time (sec)

Phas

e (w

aves

)

seed laser SCOWA

λ/2 λ/4

λ/2

NP

NP

Pol.

P.D. (I)

P.D. (Q)

P.D.

+-

Pol.

seed laser SCOWA

λ/2 λ/4

λ/2

NP

NP

Pol.

P.D. (I)

P.D. (Q)

P.D.

+-+-

Pol.

Mach Zehnder Interferometer measures Phase for Feedback Control

1 wave per 180 mA of Diode Current

<5GHzBandwidth

Stabilized Diode Amplifier Output Phase to 0.01 waves at 1 µm!Challenge: Coherent Array of High Power Laser Diode Amplifiers at 2 kW

500 mW SCOWL Amplifier OpenLoop

ClosedLoop

Phase Noise

(rad/√Hz)

Integrated Phase Noise

(rad)

10-1 100 101 102 103 10410-5

10-4

10-3

10-2

10-1 SCOWA#3 @300mA, 15mW seed SCOWA#3 @700mA, 15mW seed SCOWA#3 @1000mA, 15mW seed

SCOWA #4 @300, 700, & 1000mA

Phas

e N

oise

(rad

/Hz1/

2 or r

ad.)

Frequency (Hz)

SCOWA Phase Noise

Page 19: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

COCHISE Diode Protection Technology Accelerated Diode Bar Lifetest

Rare Rogue Events Lead to Catastrophic Damage

in Diode Bar

Eliminating Rogue Modes extends Diode Bar Lifetime by >10xNo Impact on Average Power or Efficiency

Fault Mode Frequency increases with Diode Bar Current

Protected UnprotectedExtend Laser Diode Bar Lifetime

Detect Fault Modes from the ElectricalTerminals of the Diode BarCut Power to the Diode Bar within 1 µsecWait for 300 µsec and Re-apply Power to the Bar

Unprotected Fault Mode Protect

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

0 50 100 150 200 250

Nor

mal

ized

Opt

ical

Pow

er

0

5

10

15

20

25

Faul

ts (

x 1

04 )

Shots ( x 106)

Lifetest terminated

120A50%

130A62.5%

150A75%

30 hours13 hours

Unprotected Fault Mode Protect

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

0 50 100 150 200 250

Nor

mal

ized

Opt

ical

Pow

er

0

5

10

15

20

25

Faul

ts (

x 1

04 )

Shots ( x 106)

Lifetest terminated

120A50%

120A50%

130A62.5%130A62.5%

150A75%

150A75%

30 hours13 hours

Fault Protected

Page 20: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Efficiency = 50% 70% SHEDS=

Cochise Program Goals

Lifetime = 10 – 100 hours >1000 hrsfor HELLADS and SHEDs

High Power per Bar = 85 watts/bar for HELLADS then >100 watts/bar

Coherent Combination = No Yes

COCHISERevolutionizing Laser Diode Bar Technology

Unique COCHISE Diode ProtectionExtends Diode Lifetime by >10x

Diode Beam Quality = 35x Diffraction Limit< 1.4x Diffraction Limit

Brightness and

Coherence

GEN3 Fault ProtectionHELLADS Phase 4

+

+

Page 21: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Cochise will increase Power and Safe Operating Temperature of Laser Diode Bars

Cochise will increase Power and Safe Operating Temperature of Laser Diode Bars

In Year 2, COCHISE will Extend HELLADS Diode Bar Lifetime at Higher:– Diode Bar Power 85 Watts >100 Watts– Inlet Coolant Temperatures 35oC >50oC

Reduce Laser Weapon System Size, Weight, and Cost– Impacts:

• HELLADS Phase 4 • DARPA Fiber Laser Program• All DoD Diode-Pumped Solid State Laser Programs

Challenge: 200 watts/bar-cm by Combining Diode Protection with Improved Bar Cooling Technology

Page 22: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Phase I

24 mo

Phase II

30 mo

Phase 0

12 mo

10

100

1

Pow

er p

er A

pert

ure

(wat

ts)

1000

Hig

h Po

wer C

omp

Dev

elop

High Power Array Development

Algorithms, Atmospherics

Low-power Testbed at ARL

Single aperture- Wide-angle- Adaptive Optics- 100 Watt- 25 mm φ

Demonstrates:- Power Scaling- SPGD Control- Adaptive Optics- 45° FOR

Single aperture- Adaptive Optics- 1000 Watt- 50 mm φ

7 Subapertures- Adaptive Optics- @ 50 mm φ- Wide-angle- @ 200 W

19 Subapertures- Adaptive Optics- @ 50 mm φ- Wide-angle- @ 1 kW

High Power Testing

at AFRL Kirtland

Proposed RoadmapProposed Roadmap

7 Subapertures- Adaptive Optics- @ 25 mm φ- @ 10 W?

Page 23: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Technologies– Conformal Phased Array – Risley Prisms– Gimballed

Programs– HELLADS (TTO) – HPFL (TTO) – ADHELS/COCHISE

Technologies– Thin Disks – Fiber – Coherent Diode Arrays

Challenges– Scalability– Efficiency – Beam Quality/Coherence – Size, Weight, Power

Solid-State Laser Amplifiers

Beam Directors

Program– APPLE

Challenges– Efficient– All-Electronic Steering– Scalable to High Power

and Aperture Size– Conformal to Platform – Minimum Size/Weight

Page 24: Electronically-Steerable, Coherent Laser Arrays · 2011. 5. 14. · Narrowline, Kilowatt-Class Fiber Lasers Weapon Concepts Require Single-Mode, Narrowline, Kilowatt-Class Fiber Lasers

Technologies– High Efficiency Edge/VCSEL/QD Emitters– Slab-Coupled Optical Waveguide

SE-Distributed Feedback– Intelligent Diode Protection

Technologies– Thin Disks – Fiber Lasers– Direct Diode Drive

– Coherently-Combined Diode Arrays– Spectrally-Combined Diode Arrays j

Technologies– Conformal Phased Array

Solid-StateLaser

Amplifier

Diode-Pumped, Solid-State Laser Systems

θDL(M2 = 1)

Divergence Angle = θ = M2 θDL

θLaser Diode

Array

Prime Power, Pprime

ηLDA ηSSL Atmospheric Transmission– Turbulence (including aero-optics)– Absorption (molecular/aerosol)

TargetIrradiance(watts/cm2)

AdaptiveOptics

Power Delivery Efficiency ~ ηLDA ηSSL ηBDM4

Challenges– Power– Efficiency– Beam Quality– Size and Weight– Lifetime/Reliability– Electronically-steered, Conformal

Optical Phased Arrays with AO

Programs– SHEDS– ADHELS/COCHISE

Laser Diodes

Solid-StateLaser

Amplifier

Programs– HELLADS (TTO) – HPFL (TTO) – ADHELS/COCHISE

Solid-State Laser AmplifiersBeam Directors

Program– APPLE

Beam Director

(Diameter D)

Beam Director

(Diameter D)

ηBD

Agenda:

– APPLE Beam Directors– COCHISE Coherent Diode Arrays– Coherent Diode Arrays integrated with APPLE– Challenges