1. Mercury Laser Diode Arrays
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
The laser diodes are the pump excitation source for the Mercury Laser system and are critical to its efficient operation.
RJB/VG Mercury Laser IFE Meeting 6

2. 3 backplanes are complete, 4th backplane by December
We have completed the V-BASIS packages for three entire backplanes (>240 kWpeak optical pump power)
Split backplane holds 36 V-BASIS tiles
3 backplanes are complete, 4th backplane by December
RJB/VG Mercury Laser IFE Meeting 6

3. V-BASIS package components
Microlens
array and
frame
Metalized
silicon
AlN
layer
Molybdenum
base
RJB/VG Mercury Laser IFE Meeting 6

4. 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,
6 to 8 µ In, (Top only)
Top of Mo Block
6 to 8 µ In,
After Si, ALN & Mo parts
are assembled
3 to 6 µ In, is deposited
on V-Groove side of Si.
Bottom side of Si,
V-Contacts
6 to 8 µ In, (Bottom only)
Shorting Clamp
Diode Bars
Micro Lens Array
AR Coated
RJB/VG Mercury Laser IFE Meeting 6

5. V-BASIS current flow path
P-Side
Connector
N-Side
P-Side to N-Side
Jumper
Connector Paddle
Shorting Clamp
Water
Flow
Heat Sink
Clamping Screws
RJB/VG Mercury Laser IFE Meeting 6

6. The diode backplane has the required brightness and thermal performance
Fast axis
brightness
Slow axis
brightness
The diode backplane provides
suitable mechanical tolerance
and cooling
Intensity
RJB/VG Mercury Laser IFE Meeting 6

7. Histogram of center wavelengths of 80 fabricated V-BASIS packages
134 amps peak for pulse integrated spectrum and 115 amps for instantaneous chirp measurement
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

8. The V-BASIS packaged diode bars meet the optical specifications of the Mercury Laser System
100 W
peak/bar
115 W
44%
2.75 kW
(23 bars)
Mercury requirement
RJB/VG Mercury Laser IFE Meeting 6

9. Summary Requirement 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)
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