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UV CHARACTERIZATION OF ENGINEERING QUALIFICATION MODEL OF ALADIN LASER TRANSMITTER

INTERNATIONAL CONFERENCE ON SPACE OPTICS 2006

Nordwijk 27 JUNE 2006

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ALADIN instrumentALADIN instrument--Transmitter Laser Assembly (TXA)Transmitter Laser Assembly (TXA)

Laser Output Requirements

Parameter Aladin TXA

Energy/pulse > 150 mJPolarisation Linear, better than 100 :1M2 < 3.5Pulse duration ≤ 100 ns FWHMPulse linewidth ≤ 50 MHz FWHM

Spectral purity99% of the pulse energy within 90MHz

Frequencystability

< 4 MHz rms over the measurementtime

Tunability ±7.5GHz for adjustm.±5 GHz in calibr. mode

Tuningaccuracy

< 1 MHz rms over 28 min (noise)< 1.7 MHz rms over 28 min (slowdrift)

Physical & Environmental Requirements

Parameter Aladin TXA

Mass PLH +RLH<31kgTLE< 23 kg

Stiffness (first eigen-frequency for rigid boundaryconditions)

PLH > 140 HzRLH > 300 HzTLE > 300 Hz

Single side conductivecoolingcold plate interfacetemperature

22oC + 1°C

Average power consumption < 470 W

Most stringent requirements :Most stringent requirements :--Frequency stability and tuning accuracy.Frequency stability and tuning accuracy.--Environmental requirements, especially mass, stiffness and thermEnvironmental requirements, especially mass, stiffness and thermal I/F with al I/F with AladinAladin instrument.instrument.--Lifetime.Lifetime.

Reference LaserHead(RLH)

Power LaserHead(PLH)

Transmitter LaserElectronics (TLE)

connector

connector

Transmitter Assembly (TXA)

Electrical I/FElectrical I/F

Laserbeam

Reg. PowerBus (BR)

Unreg. PowerBus (BNR)

Electrical I/F

ALADIN Control & DataManagement Unit

(ACDM)

Fiber

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ALADIN instrumentALADIN instrument--TXA Functional Block DiagramTXA Functional Block Diagram

RLH PLH

TLE

PLH is a diodePLH is a diode--pumped, Qpumped, Q--switched switched NdNd:YAG Laser frequency tripled:YAG Laser frequency tripledand it is composed of 4 main subunitsand it is composed of 4 main subunits::

--A low energy A low energy NdNd:YAG Master Oscillator (MO), injection seeded :YAG Master Oscillator (MO), injection seeded QQ--switched and longitudinally laser pumped by laser diodes.switched and longitudinally laser pumped by laser diodes.--A first amplifier (A first amplifier (PreAPreA) in a double pass configuration ) in a double pass configuration (transversally diode pumped).(transversally diode pumped).--A second power amplifier (A second power amplifier (PwAPwA) in a single pass configuration ) in a single pass configuration (transversally diode pumped).(transversally diode pumped).-- A Harmonic Section (HS) employing two nonA Harmonic Section (HS) employing two non--linear crystals.linear crystals.

Ligth TrapMaster Oscillator

MO Cavity

PumpDiodes

PZT

Q-Switch

Activemedium

PreAmplifier

Amplifier

PumpDiodes

Activemedium

PumpDiodes

HarmonicConverter &Wavelength

Selector UV Laser Pulse

1st & 2ndharmonic

Seeder Laserbeam from RLH

(via optical fibre)

PLH

LD pumpingcurrent pulse

from TLE

LD pumpingcurrent pulse

from TLE

LD pumpingcurrent pulse

from TLE

PZT driving fromTLE (Cavity Length

Control Loop)

Q-Switch HV andcontrol signal

from TLE

PT1000(to TLE)

EnergyMonitoring

(to TLE)

HC TemperatureControl

from TLE

Heater(s)

Heater Driverfrom TLE

ReferenceLaser

10 GHzPhotodiode

I/F &Control

Unit

DC/DCConv.

SeederLaser

3 dBCoupler

FM ModulatorULE Cavity

Reference LaserLocking

Electronics

PowerSplitter

FrequencyLocking Loop

10%

90%

SeederLaser

to PLH

TC(from TLE)

TM(to TLE)

P/S(from TLE) PT1000

(to TLE)

Heaters

BNR

EMI Filter

Interface & Control Section

CavityLenghtControlBoard

I/F &ControlModule

Direct Telemetries

PDTempSensors

HeatersControl

Q-switchPiezoControl

PD

Q-switch HV & Aux Voltage

AmpLD Pump Current

PreAmpLD Pump Current

MOLD Pump Current

RLH Power SuppliesBR

Synchros CMDs

Direct TemperatureTelemetry

PLHheaters

PreAmp LDPSM

Amp LDPSM

MO LDPSM

LV/HV PSU

HKVoltages

PLH_HTR ON/OFF(From I/F Section)

3

TeleCommandsTeleMetries

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ALADIN instrumentALADIN instrument-- Laser Transmitter UnitsLaser Transmitter Units

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ALADIN instrumentALADIN instrument-- PLH Optical LayPLH Optical Lay--OutOut

Piezo Monitor

Beam Expander

HR Mirror

Tablet isolator

Cylindrical lens λ/2 Isolator

INJECTION OPTICS

MO SECTION

AMPLIFIER SECTION

HG SECTION

Cylindrical Lenses

1064nm

532nm

Pre Amplifier

Polarizer λ/4 HR Mirror

Folding Mirror

Power Amplifier

Cylindrical Lenses

λ/2

355nm

SHG THG λ/2 Telescope

Piezo-Mirror

Master Oscillator

Rod

Q-Switch Photodiode

Isolator

Dichroic mirrors

Beam expander

Polarizer

Folding Mirror

Folding Mirror

Pigtail fiber

Input from RLH

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ALADIN instrumentALADIN instrument-- PLH Mechanical StructurePLH Mechanical Structure

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ALADIN instrumentALADIN instrument--PLH Main Subassemblies: MOPLH Main Subassemblies: MO

Pumping diodes

Polarizer

EO Q-switch

Nd:YAG rod

Outcoupler mirror

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ALADIN instrumentALADIN instrument--PLH Main Subassemblies: AMPLIFIERSPLH Main Subassemblies: AMPLIFIERS

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ALADIN instrumentALADIN instrument--PLH Main Subassemblies: HARMONIC SECTIONPLH Main Subassemblies: HARMONIC SECTION

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TXA EQM EXPERIMENTAL RESULTSTXA EQM EXPERIMENTAL RESULTSTable 1. Main UV Laser Output Performance

Parameter EQM Measurement Energy/pulse 107 mJ (mean during ON period) M2 ≤ 3 Pulse duration 18.4 ns (FWHM)

Beam Angular Stability 24.4 µrad X (zig-zag plane) 28.7 µrad Y (orthogonal to zig-zag plane)

Spectral linewidth 40 MHz (FWHM) Frequency stability 3.7 MHz (rms value)

Table 1. Physical Data & Budgets Parameter EQM Measurement

Mass PLH EQM = 27.3 kg RLH EM = 2.4 kg TLE EM < 22.2 kg

Volume PLH = 450x350x215 mm3 RLH < 150x120x75 mm3 TLE < 450x345x230 mm3

Stiffness

PLH Resonance frequency X axis 182 Hz Y axis 288 Hz Z axis 251 Hz

RLH Resonance frequency X axis 347 Hz Y axis 342 Hz

TLE Resonance frequency X axis 220 Hz Y axis 430 Hz Z axis 510 Hz

Cold Plate 24 ± 1 °C Power consumption 440 W (measured average value)

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TXA EQM EXPERIMENTAL RESULTSTXA EQM EXPERIMENTAL RESULTS

0 2 4 6 8 10 120

90

180

270

360

450

IR energy @ SHC input Emean=402 mJ Emax=420 mJEmin=375 mJ

UV energy @ dichroic outputEmean= 107 mJ Emax = 128 mJ Emin = 69 mJ

UV

energy (mJ)

IR 3

rd p

ass

ener

gy (

mJ)

Time (s)

0

30

60

90

120

150

IR/UV Energy during 12 s. The reported values

refer to last 7 s useful period

Typical UV Near Field profile

Typical UV Far Field profile

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TXA EQM EXPERIMENTAL RESULTSTXA EQM EXPERIMENTAL RESULTS

UV Frequency stability

-15

-10

-5

0

5

10

15

5 6 7 8 9 10 11 12ON Period (s)

Fre

qu

ency

var

iati

on

(M

Hz)

Typical UV pulse temporal profile

UV beam angular stability during a burst

Optical frequency stability

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TXA SPECIFIC PROVISIONSTXA SPECIFIC PROVISIONS

MOC exposition PLH EQM curve

Cleanliness/Contamination

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TXA SPECIFIC PROVISIONSTXA SPECIFIC PROVISIONS

In-Flight monitoring and control

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TXA SPECIFIC PROVISIONSTXA SPECIFIC PROVISIONS

TXA functional mode diagram and mode control parameters