cfao retreat: march 26, 2007 1 review of laser guidestar activity at lmct

CfAO Retreat: March 26, 2007 1

Review of Laser Guidestar Review of Laser Guidestar Activity at LMCTActivity at LMCT

Review of Laser Guidestar Review of Laser Guidestar Activity at LMCTActivity at LMCT


AgendaAgendaAgendaAgenda

• Update on AODP– Phase 2 Objectives– Delay Issues– Fiber Testing– Waveguide Delivery / Performance– Schedule Looking Ahead

• Update on SFG Activities

• Brief update on GSK

• Update on AODP– Phase 2 Objectives– Delay Issues– Fiber Testing– Waveguide Delivery / Performance– Schedule Looking Ahead

• Update on SFG Activities

• Brief update on GSK


Phase 2 ObjectivesPhase 2 ObjectivesPhase 2 ObjectivesPhase 2 Objectives

• Complete Relay Fiber Testing

• 1064 nm Power Milestone (83 W)– 2 Full Talbot-length WGs


• 589 nm Power Milestone (50 W)– Based on 30% conversion efficiency

• Complete Relay Fiber Testing



• 589 nm Power Milestone (50 W)– Based on 30% conversion efficiency


AODP Delay IssuesAODP Delay IssuesAODP Delay IssuesAODP Delay Issues

• Waveguide deliveries:– The primary WG vendor has delivered over 12 WGs to

specification that meet performance criteria– The primary WG vendor is now also meeting schedule.– Both bonded and epoxied WGs are performing

• Resources:– Both AODP and GSK has lost key personnel in the last 3

months– Due to the higher priority of GSK, Munib Jalali was pulled off

of AODP– Jo Bellanca (Research Scientist) now working on AODP

• AODP Phase 2 scheduled to conclude in September 2007.

• Waveguide deliveries:– The primary WG vendor has delivered over 12 WGs to

specification that meet performance criteria– The primary WG vendor is now also meeting schedule.– Both bonded and epoxied WGs are performing

• Resources:– Both AODP and GSK has lost key personnel in the last 3

months– Due to the higher priority of GSK, Munib Jalali was pulled off

of AODP– Jo Bellanca (Research Scientist) now working on AODP

• AODP Phase 2 scheduled to conclude in September 2007.


Relay Fiber TestingRelay Fiber TestingRelay Fiber TestingRelay Fiber Testing


LMCT Relay FiberLMCT Relay FiberLMCT Relay FiberLMCT Relay FiberRelay Fiber: 100 m

• Supplier – Crystal Fiber

• Type – 12.5 m MFD solid core photonic crystal fiber (PCF)

• Attenuation – < 8.5 dB/km

• NA = 0.04

Relay Fiber: 100 m

• Supplier – Crystal Fiber

• Type – 12.5 m MFD solid core photonic crystal fiber (PCF)

• Attenuation – < 8.5 dB/km

• NA = 0.04

0

40

80

120

160

200

10 20 30 40 50 60 70 80 90 100

Fiber Length (m)

Th

resh

old

SB

S P

ow

er (

W)

100 MHz 500 MHz1 GHz 2 GHz

0

40

80

120

160

200

10 20 30 40 50

Fiber Length (m)

Th

resh

old

SB

S P

ow

er (

W)

100 MHz 500 MHz1 GHz 2 GHz

SBS: Pth = CBAeff / gBLeffSBS: Pth = CBAeff / gBLeff


Lens = 25.4 mm

Half Waveplate Setting

(deg.)

Half Waveplate

Setting (deg.)

50mm Stanfo

rd PPSLT 589nm

CW-Power

(W)

Crystal Temp (deg.

C)Output

fiber

Coupling efficienc

y

84 296.0 0.750 83.4 0.3825 51%

91 290.0 1.060 83.1 0.53 50%

98 285.0 2.120 82.6 1.0176 48%

105 280.0 3.560 82.4 1.8156 51%

115 274.0 4.650 82.0 2.3715 51%

263.0 5.120 81.7 2.5088 49%

Fiber Attenuation: 14%

Fresnel Losses 14%

Coupling Losses: 8%

Expected: 64%

CW Testing – 50 mm Stanford CrystalCW Testing – 50 mm Stanford Crystal

Fiber length: 100 m

Fiber attenuation: 0.0085 dB/m

Linewidth: 305 MHz

Fiber MFD: 12.5 micron

SBS limit: 3.34 W


50mm Stanford PPSLT 589nm CW-Power (W)

Crystal Temp

(deg. C)Output

fiber Coupling efficiency

1.800 83.4 1.188 66%

3.100 83.1 1.984 64%

4.500 82.6 2.79 62%

6.000 82.4 3.72 62%

8.500 82.0 4.93 58%

10.600 81.7 6.148 58%

ML Testing – 50 mm Stanford Crystal

• 630 MHz, 430 ps pulses

ML Testing – 50 mm Stanford Crystal

• 630 MHz, 430 ps pulses

Fiber length: 100 m


Linewidth: 630 MHz


SBS limit: 6.90 W

Fiber length: 30 m


Linewidth: 630 MHz


SBS limit: 21.49 W


ConclusionsConclusionsConclusionsConclusions

• Improvements to be made with regards to Fresnel losses via AR coating and fiber losses via shorter fiber.

• No SRS observed in these experiements

• May have some SBS present at higher power levels, but we are right on the threshold

• Will continue tests once AODP setup is up and running again.

• Improvements to be made with regards to Fresnel losses via AR coating and fiber losses via shorter fiber.

• No SRS observed in these experiements

• May have some SBS present at higher power levels, but we are right on the threshold

• Will continue tests once AODP setup is up and running again.


Sum Frequency Generation of 589Sum Frequency Generation of 589 Sum Frequency Generation of 589Sum Frequency Generation of 589


Stanford Crystal PerformanceStanford Crystal PerformanceStanford Crystal PerformanceStanford Crystal Performance

• 50 mm PPSLT crystal

• Poling ranges from 10.6 – 10.9 um

• Several channels damaged at higher fluence levels ~ 21 J/cm2

• These were the 10.6 -10.7 um channels

• To be cautious, we increased spot size to ~ 100 um in order to avoid damage while still generating > 10 W.

• 50 mm PPSLT crystal

• Poling ranges from 10.6 – 10.9 um

• Several channels damaged at higher fluence levels ~ 21 J/cm2

• These were the 10.6 -10.7 um channels

• To be cautious, we increased spot size to ~ 100 um in order to avoid damage while still generating > 10 W.


Mode-Locked SFG Performance (100um waist; 10.8um poled Channel)

0.00

2.00

4.00

6.00

8.00

10.00

12.00

0.00 5.00 10.00 15.00 20.00 25.00 30.00

IR Input Power (W)

58

9n

m O

utp

ut

Po

we

r (W

)

0.00%5.00%10.00%15.00%20.00%25.00%30.00%35.00%40.00%45.00%50.00%

SF

G C

on

ve

rsio

n

Eff

icie

nc

y

589nm Output Power (W) SFG Conversion Efficiency

SFG Performance – Stanford 50 mm CrystalSFG Performance – Stanford 50 mm Crystal


SFG Data vs ModelSFG Data vs ModelSFG Data vs ModelSFG Data vs Model

Mode-Locked SFG Performance (100um waist; 10.8um poled Channel)

0

2

4

6

8

10

12

14

16

18

0.00 5.00 10.00 15.00 20.00 25.00 30.00

IR Input Power (W)

58

9n

m O

utp

ut

Po

we

r (W

)

589nm Output Power (W) Modeled Power


ConclusionsConclusionsConclusionsConclusions

• Damage to Stanford crystal at higher fluence levels needs further investigation

• Will perform side-by-side test of Stanford, Deltronics, and PSI crystals

• Will work with vendors to understand damage mechanisms & how to correct.

• Damage to Stanford crystal at higher fluence levels needs further investigation

• Will perform side-by-side test of Stanford, Deltronics, and PSI crystals

• Will work with vendors to understand damage mechanisms & how to correct.

cfao retreat: march 26, 2007 1 review of laser guidestar activity at lmct

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