SLD3233VF |
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. |
|
* Maximum optical power output:
120 mW (pulse drive mode)
* Low power and low noise
* High-temperature (75C°)
operation guaranteed |
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Maximum Optical Power
Output: 120 mW
(in pulse drive mode) |
|
Sony has already released the
SLD3232VF (pulse drive mode maximum
optical power output: 65 mW) blue-violet
laser diode as a light source for Blu-ray
Disc drives. Even higher power levels,
however, are now required in the blue-violet
lasers that are used as the light
source, to make higher recording densities
and speeds possible in Blu-ray Disc
Recorders. The newly-developed
SLD3233VF minimizes reductions in
reliability due to catastrophic optical damage (COD) by optimizing the laser
structure and controlling the optical power
density distribution in the optical region.
As a result, Sony was able to create a blue-violet
laser diode that is capable of a maximum
optical power output of 120 mW in
pulse drive mode. |
|
Low Power and Low Noise |
|
The blue-violet laser diode, whose base
material is gallium nitride, is a device in
which, due to the physical properties of
the material itself, it is extremely difficult
to acquire good current – voltage characteristics.
Nonetheless, by adopting optimal
electrode materials and structures,
Sony was able to achieve laser operation
at an operating voltage of 4.9 V (typical)
(25C°, 65 mW CW drive mode). Sony also
achieved, at the same time, both the low
threshold current of 35 mA (typical)
(25C°, CW drive mode) and the high
differential efficiency of 1.5 mW/mA
(typical) (25C°, CW drive mode) by
optimizing the structure of the area around
the emission point. As a result, it was also
possible to achieve the low power of 0.39
W (typical) (25C°, 65 mW CW drive
mode). Due to the reduction of the threshold
current, it was also possible to reduce
the natural optical emission component,
which can cause fluctuations in the optical
power output. |
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High-Temperature (75C°)
Operation Guaranteed |
|
During recoding by a Blu-ray Disc
Recorder, the heat generated by both the
structural components and the laser itself
becomes significant. Also, since the internal
areas of hardware used in IT applications
can reach extremely high temperatures,
high reliability in high-temperature
environments is necessary in laser diodes.
New structures were introduced in the
optically active areas in the newly-developed
SLD3233VF allowing this device to
exhibit high resistance to temperature
changes. The SLD3233VF’s temperature
characteristics are superlative, even when
compared to red laser diode of conventional
CD and DVD light sources, and this
device can achieve stable operation even
under severe environments with an environmental
temperature of 75C°. |
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•••• Mr.MIZUNO••••
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Blue-violet laser diodes are extremely
difficult to design since
they use new material families and
processes. In addition, since this
development project required doubling
the optical power output over
earlier products, there were many
high hurdles that we had to deal
with before we arrived at a product.
Still, in the future, even higher
recording speeds will be achieved
in Blu-ray Disc systems. To
respond to these market needs,
our development staff will work together
as an integrated team to
develop devices with even higher
output levels. |
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See
all articles with figures and tables.  |
|
Vol.40 |
|
