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Two-Wavelength DVD Player Laser Diode Improves Optical System Design Flexibility
and Features Improved Resistance to ESD
SLD6164RL
Sony led the industry in developing multimode two-wavelength laser diodes
that do not require a high-frequency superposed circuit.
Now, the SLD6164RL, which achieves a high resistance to damage from
ESD in the DVD side and increases the optical output, increases ease of
use even further.
The rated output levels have been increased by 25% over earlier products
to 5 mW in both the DVD and CD side devices.
This device can handle limited optical systems and increases the design
flexibility in end product optical systems even further.
The resistance to ESD in the DVD side has been increased to over 80 V,
twice that of the earlier SLD6163RL, and thus this device can contribute
to reducing the cost of antistatic measures in end product manufacture. |
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SLD6164RL |
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* Multimode two-wavelength laser
diode that does not require a high-frequency
superposed circuit
* DVD side resistance to ESD: 80 V
or higher
* Rated output of 5 mW (CW, 70C
operation guaranteed) for both the
DVD and CD sides |
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Multimode Two-Wavelength
Laser Diode that does not
Require a High-Frequency
Superposed Circuit |
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In optical disc systems, light reflected
from the disc with irregular amplitude, the
so-called “returning light”, can disrupt
laser operation and generate noise. While
this noise is usually excluded using a high-frequency
superposed circuit, these high-frequency
modules have a high current consumption and undesired radiation
countermeasures are required.
In the SLD6164RL, a self-pulsation type
device is used on the DVD side and an
amplifying waveguide type multimode
laser is used on the CD side. Sony applied
the industry-leading basic technologies
used in the SLD6162RLI and
SLD6163RL products in the SLD6164RL
to achieve a low-noise laser that does not
require a high-frequency superposed
circuit. This allows both costs and power
consumption to be reduced, and also
obviates the need for undesired radiation
countermeasures. |
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DVD Side Resistance to ESD:
80 V or Higher |
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Laser diodes are easily damaged by ESD
and other instantaneous high currents, and
thus antistatic and anti-surge measures are
absolutely required in manufacturing lines
that handle laser devices.
Conventional self-pulsation type lasers
usually have a low resistance to ESD as
compared to the lasers used for recording.
The SLD6164RL, however, achieves
a level of 80 V or higher for the DVD side
forward direction ESD resistance
(machine model test). Thus it has a resistance
to damage from ESD twice that of
conventional products and can enable
reduced costs in antistatic measures. (See
figure 2.) |
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Rated Output of 5 mW (CW/70C°
operation guaranteed) for both
the DVD and CD Sides |
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Catastrophic optical damage (COD) is a
problem that prevents achieving higher
output in a laser diodes. If the laser is
driven at a level above the output limit (the
COD output), the optical emission surface
(end surface) of the laser chip melts due
to heat generation, leading to a cessation
of light generation. Sony has applied their
unique laser chip end surface strengthening
technologies in the SLD6164RL
resulting in an increase in the output limit
to twice that of previous Sony products.
(See figure 3.) The rated output is set at 5
mW, a 25% increase over earlier products,
and continuous operation (CW operation)
is guaranteed in operating environments
up to 70C°.
This allows the SLD6164RL to provide
greater flexibility in optical system design
and to handle limited optical systems. |
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•••• Mr.SAITO••••
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The self-pulsation laser diode is a
product that depends on a delicate
balance between current applied
and the light enclosed, and as a
result has the problem that introducing
high output/high resistance
to ESD technologies can
disturb that balance and aggravate
noise characteristics. It was extremely
difficult, given the short
development period, to find the
precise balance for high output
and low noise by adjusting various
design parameters. I hope that
we will continue to provide new
products such as this that increase
end product design flexibility
for our customers. Keep your
eye on Sony for further developments
in this area! |
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See
all articles with figures and tables.  |
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Vol.39 |
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