Mercury

Mercury Laser Diode Arrays

RJB/VG Mercury Laser IFE Meeting 6

Barry Freitas, Dave Van Lue, Joe Satariano, Everett Utterbach, Larain DeMercurio, Kurt Cutter,

Terry Delima, Ray BeachHAPL Review

Crowne Plaza HotelPleasanton, CA

November 13, 2001

We have completed the V-BASIS packages for three entire backplanes (>240 kWpeak optical pump power)

3 backplanes are complete, 4th backplane by December

Split backplane holds 36 V-BASIS tiles

RJB/VG Mercury Laser IFE Meeting 6

V-BASIS package components

Microlensarray and frame

Metalized silicon

AlNlayer

Molybdenumbase

.notchSi submount

Mo block

Si lensframe

AlN sheet

microlens

diode

spring

23-bar V-BASIS: etched Si heatsink

- Mo-base expansion-matched to Si- Thin AIN layer for electrical isolation- V-Spring adhesion-enhanced with epoxy

.notchSi submount

Mo block

Si lensframe

AlN sheet

microlens

diode

spring

23-bar V-BASIS: etched Si heatsink

- Mo-base expansion-matched to Si- Thin AIN layer for electrical isolation- V-Spring adhesion-enhanced with epoxy

RJB/VG Mercury Laser IFE Meeting 6

V-BASIS diode tile and plating specifications

V-Groove side of Si,100 to 200 Å Ti,10 to 12 µ Ag,1000 to 1200 Å Ni,1000 to 1200 Å Au,

Top and Bottom of ALN, 1000 to 1200 Å Ti,1000 to 1200 Å Ni,1000 to 1200 Å Au,6 to 8 µ In, (Top only)

Top of Mo Block1000 to 1200 Å Ti,1000 to 1200 Å Ni,1000 to 1200 Å Au,6 to 8 µ In,

After Si, ALN & Mo parts are assembled3 to 6 µ In, is depositedon V-Groove side of Si.

Bottom side of Si,100 to 200 Å Ti,1000 to 1200 Å Ni,1000 to 1200 Å Au,

V-Contacts1000 to 1200 Å Au,6 to 8 µ In, (Bottom only)

Shorting Clamp1000 to 1200 Å Au,

Diode Bars

Micro Lens ArrayAR Coated

RJB/VG Mercury Laser IFE Meeting 6

V-BASIS current flow path

P-SideConnector

N-SideConnector

P-Side to N-SideJumper

P-SideConnector Paddle

N-SideShorting Clamp

Water Flow

Heat Sink Clamping Screws

RJB/VG Mercury Laser IFE Meeting 6

890 895 900 905 910

0.0

0.2

0.4

0.6

0.8

1.0 1Hz 5Hz 10Hz

A.U.

Wavelength (nm)

-0.3 -0.2 -0.1 0.0 0.1 0.2 0.30.0

0.2

0.4

0.6

0.8

1.0

Inte

nsit

y

Radians

1 Tile 10 Tiles

-0.15 -0.10 -0.05 0.00 0.05 0.10 0.150.0

0.2

0.4

0.6

0.8

1.0

Inte

nsit

y

Radians

1 Tile 10 Tiles

The diode backplane has the required brightness and thermal performance

Fast axisbrightness

Slow axisbrightness

Inte

nsity

The diode backplane provides suitable mechanical toleranceand cooling

RJB/VG Mercury Laser IFE Meeting 6

Histogram of center wavelengths of 80 fabricated V-BASIS packages

897 898 899 900 901 9020

5

10

15

20

Wavelength Distribution of 80 V-BASIS Packages

Nu

mb

er

of V

-BA

SIS

Pa

cka

ge

s

nm

Remember, our original modeling specified a gaussian spread with a FWHM of ~ 8 nm. While this distribution is not gaussian it is narrower overall than we had originally anticipated.

RJB/VG Mercury Laser IFE Meeting 6

The V-BASIS packaged diode bars meet the optical specifications of the Mercury Laser System

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.60

500

1000

1500

2000

2500

3000

Power(W)

Shots (10^8)

100 Wpeak/bar

115 Wpeak/bar

0 20 40 60 80 100 120 1400.0

0.1

0.2

0.3

0.4

0.5

Efficiency

Current (A)

44%

0 20 40 60 80 100 120 1400

500

1000

1500

2000

2500

3000

Power(W)

Current (A)

2.75 kW(23 bars)

Mercury requirement

RJB/VG Mercury Laser IFE Meeting 6

SummaryRequirement Status

100 Wpeak/bar 115 Wpeak/bar

Fabrication of 120 tiles

(144 tiles per amplifier head)

Completed

45% electrical to optical efficiency

44% demonstrated almost

Reliability of > 2x108 shots

1.4x108 shots without problems

Every package is burned in for 5x106 shots (75 Hz for 18+

hours)

almost

Power droop during pulse

< 15%

5% droop demonstrated

Assemble tiles on split backplane

3 backplanes have been completed, the 4th will be

completed by the end of the calendar year

Pulse-integrated linewidth

< 8.5 nm FWHM

Demonstrated 4.7 nm FWHM on tiles for backplane

RJB/VG Mercury Laser IFE Meeting 6