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Open Package 330 mW Laser Diode
for High-Speed CD-R/RW Optical Disc Recording
SLD255JL
Now that we are well into the high-speed network age, desires for even higher
speed data recording CD-R/RW drives have been increasing recently, and higher
output power is now strongly desired in the laser diodes used in these drives to
meet the “optical power output proportional to the square root of the speed multiplier”
rule of thumb. Also, in combo drives that use an optical pickup that shares a
common optical system with the DVD system laser, even higher output specifications
are required to make up for the output loss due to the optical system.
Sony has responded to these needs up to now with laser diode products through
the SLD253 family. However, there are now strong demands from the market for
devices that can support the high-speed write scribe function*1 and can be provided
at even lower costs.
To respond to these demands, Sony has developed and is now releasing the
SLD255JL that features 330 mW pulse/150 mW CW specifications and is provided
in an open package.
*1: Write scribe: a drive function that draws text, graphics, and photographs on the label side of the CD-R disc by operating the
laser in high-output CW mode. |
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SLD255JL |
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* Rated output: 330 mW (up
to 50 ns, 50% duty, 75C°)/150 mW (CW, 75C°)
* Supports high-speed
write scribe drives
* First open package laser
diode in the 330 mW class |
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Rated Output: 330 mW (up to
50 ns, 50% duty, 75C°)/150
mW (CW, 75C°) |
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The following two improvements are required
to provide even higher laser output
power levels. First, the optical efficiency
must be increased by reducing the loss
within the waveguide. Second, catastrophic
optical damage (COD), in which
the optical emission surface is melted by
its own optical energy must be avoided
(that is, the lifetime of the device at the
rated power level must be guaranteed).
In the SLD255JL, Sony optimized the design of the waveguide structure based
on Sony’s unique semiconductor crystal
growth technologies, metal organic
chemical vapor deposition (MOCVD) so
that transmission loss of the laser beam is
held to an absolute minimum. Furthermore,
by adopting Sony’s unique technologies
in the protective film coating on
the emission surface, Sony was able to
both increase the COD level and extend
the device lifetime.
As a result of these efforts, the SLD255JL
guarantees both high output levels (330
mW pulse, 150 mW CW) that were previously
unachievable as well as long-term
reliability. This higher output means that
the SLD255JL can also support a high-speed
write scribe function.
Furthermore, the SLD255JL inherits from
previous Sony products both the low-impedance
design that can extract the maximum
capability from the optical pickup
high-speed pulse drive circuit as well as
the interference distance nL of 3.57 mm.
This means that customers currently using
Sony products will see no changes in
the ease of use if they switch over to the
SLD255JL. Table 1 lists the main laser
specifications when the SLD255JL is
driven at 100 mW in CW operation at
25C°.
As can be seen from figures 2 and 3, the
SLD255JL has a minimal temperature
dependence in both pulse and CW drive modes, and has a power consumption design
that allows it to provide low-current
drive even at high temperatures. |
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First Open Package Laser
Diode in the 330 mW Class |
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To respond to the strong market needs for
lower prices in this area, given that the
required long-term reliability had been
assured, Sony has led the industry by
adopting, for the first time in a 300 mW
class laser diode, an “open package”,
which eliminates the glass cap.
Sony also provides, as a product line of
similar high-output/low-cost laser diodes,
both the even lower priced SLD253JL and
the nL = 3.41 mm interference distance
SLD251JL to support a wide range of customer
needs.
Sony is committed to continuing to develop
products that lead the industry in
meeting customer needs, and will respond
to these needs with even higher output
power and even lower prices. |
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•••• Mr.SUGAWARA••••
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We put a lot of effort into this rapid
product development project that
aimed at both high-output operation
as well as guaranteed long-term
reliability. This was a development
effort that was also premised
on maintaining resonator
length (interference distance) and
providing ease-of-use for customers
who were already using Sony
laser diode products. I am looking
forward to future product development
efforts that can also satisfy
our customers’ needs. |
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See
all articles with figures and tables.  |
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Vol.40 |
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