High-Power Blue-Violet Laser Diode for Blu-ray Discs
SLD3233VF
I
Maximum optical power output:
120 mW (pulse drive mode)
The Blu-ray Disc Recorder can record digital high-definition television
broadcasts with superb quality and with long recording times per disc.
A blue-violet laser diode is used as the light source.
I
I
Low power and low noise
H i g h - t e m p e r a t u r e ( 7 5°C )
operation guaranteed
Sony has now developed the SLD3233VF blue-violet laser diode that
supports even higher densities and faster recording in Blu-ray Disc
Recorders.
Compared to previous products, this laser diode increases the maximum
optical power output by 55 mW and is capable of providing 120 mW in
pulse drive mode. It also can operate under severe environment condi-
tions up to a temperature of 75°C, and thus has the proven ability to func-
tion in IT applications.
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 maxi-
mum optical power output of 120 mW in
pulse drive mode.
High-Temperature (75°C)
Maximum Optical Power
Output: 120 mW
Operation Guaranteed
(in pulse drive mode)
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 inter-
nal areas of hardware used in IT applica-
tions can reach extremely high tempera-
tures, high reliability in high-temperature
environments is necessary in laser diodes.
New structures were introduced in the
optically active areas in the newly-devel-
oped 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 conven-
tional CD and DVD light sources, and this
device can achieve stable operation even
under severe environments with an envi-
ronmental temperature of 75°C.
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 densi-
ties and speeds possible in Blu-ray Disc
Recorders. The newly-developed
SLD3233VF minimizes reductions in
reliability due to catastrophic optical
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 charac-
teristics. Nonetheless, by adopting opti-
mal electrode materials and structures,
Sony was able to achieve laser operation
at an operating voltage of 4.9 V (typical)
(25°C, 65 mW CW drive mode). Sony also
achieved, at the same time, both the low
threshold current of 35 mA (typical)
(25°C, CW drive mode) and the high
differential efficiency of 1.5 mW/mA
(typical) (25°C, 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) (25°C, 65 mW CW drive
mode). Due to the reduction of the thresh-
old current, it was also possible to reduce
the natural optical emission component,
which can cause fluctuations in the opti-
cal power output.
V
O
I
C
E
Blue-violet laser diodes are ex-
tremely difficult to design since
they use new material families and
processes. In addition, since this
development project required dou-
bling the optical power output over
earlier products, there were many
high hurdles that we had to deal
with before we arrived at a prod-
uct. 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 to-
gether as an integrated team to
develop devices with even higher
output levels.