Mercury Laser Diode Arrays
Mercury
Barry Freitas, Dave Van Lue, Joe Satariano, Everett Utterbach,
Larain DeMercurio, Kurt Cutter,
Terry Delima, Ray Beach
HAPL Review
Crowne Plaza Hotel
Pleasanton, CA
November 13, 2001
RJB/VG Mercury Laser IFE Meeting 6
We have completed the V-BASIS packages for three
entire backplanes (>240 kW peak optical pump power)
Split backplane holds 36 V-BASIS tiles
3 backplanes are complete, 4 th backplane by December
RJB/VG Mercury Laser IFE Meeting 6
.
V-BASIS package components 23-bar V-BASIS: etched Si heatsink
Si lens
frame
micr olens
spr ing
ng
p ri
v-s
diode
Si submount notch
AlN sheet
Mo block
- Mo-base expansion-matched to Si
Molybdenum
- Thin AIN layer for electrical isolation
base
- V-Spring adhesion-enhanced with epoxy
AlN
layer
Metalized
silicon
Microlens
array and
frame
RJB/VG Mercury Laser IFE Meeting 6
V-BASIS diode tile and plating specifications
Micro Lens Array
AR Coated V-Contacts
1000 to 1200 Å Au,
After Si, ALN & Mo parts 6 to 8 µ In, (Bottom only)
are assembled
3 to 6 µ In, is deposited
Diode Bars
on V-Groove side of Si.
V-Groove side of Si,
Top and Bottom of ALN, 100 to 200 Å Ti,
1000 to 1200 Å Ti, 10 to 12 µ Ag,
1000 to 1200 Å Ni, 1000 to 1200 Å Ni,
1000 to 1200 Å Au, 1000 to 1200 Å Au,
6 to 8 µ In, (Top only)
Top of Mo Block
Bottom side of Si,
1000 to 1200 Å Ti,
100 to 200 Å Ti,
1000 to 1200 Å Ni,
1000 to 1200 Å Ni,
1000 to 1200 Å Au,
1000 to 1200 Å Au,
6 to 8 µ In,
Shorting Clamp
1000 to 1200 Å Au,
RJB/VG Mercury Laser IFE Meeting 6
V-BASIS current flow path
N-Side P-Side to N-Side P-Side
Shorting Clamp Jumper Connector Paddle
Water
Flow
Heat Sink
Clamping Screws
N-Side P-Side
Connector Connector
RJB/VG Mercury Laser IFE Meeting 6
The diode backplane has the required brightness
and thermal performance
1.0 1.0
Fast axis 1 Tile
Slow axis 1 Tile
0.8 0.8
10 Tiles
brightness 10 Tiles brightness
0.6 0.6
Intensity
Intensity
0.4 0.4
0.2 0.2
0.0 0.0
-0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3
Radians Radians
1.0 1Hz
0.8 5Hz
10Hz The diode backplane provides
Intensity
0.6 suitable mechanical tolerance
A.U. 0.4
and cooling
0.2
0.0
890 895 900 905 910
Wavelength (nm)
RJB/VG Mercury Laser IFE Meeting 6
Histogram of center wavelengths of 80 fabricated V-
BASIS packages
Wavelength Distribution of 80 V-BASIS Packages
20
Number of V-BASIS Packages
15
10
5
0
897 898 899 900 901 902
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
0.5
0.4
0.3 44%
Efficiency
0.2
0.1
0.0
0 20 40 60 80 100 120 140
Current (A)
3000
3000
2500
2.75 kW Mercury requirement 2500
2000 (23 bars)
Power 2000
Power 100 W 115 W
(W) 1500
(W) 1500 peak/bar peak/bar
1000
1000
500
500
0
0 20 40 60 80 100 120 140 0
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
Current (A)
Shots (10^8)
RJB/VG Mercury Laser IFE Meeting 6
Summary
Requirement Status
100 Wpeak/bar 115 Wpeak/bar
Fabrication of 120 tiles Completed
(144 tiles per amplifier head)
45% electrical to optical 44% demonstrated almost
efficiency
1.4x10 8 shots without problems
Reliability of > 2x108 shots Every package is burned in for almost
5x10 6 shots (75 Hz for 18+
hours)
Power droop during pulse 5% droop demonstrated
< 15%
Assemble tiles on split 3 backplanes have been
backplane completed, the 4 th will be
completed by the end of the
calendar year
Pulse-integrated linewidth Demonstrated 4.7 nm FWHM
< 8.5 nm FWHM on tiles for backplane
RJB/VG Mercury Laser IFE Meeting 6