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BLUE LASER DIODES EXPECTED TO MEET STANDARDS FOR DVD SUCCESSOR
According to Cree,
Inc. the new blue laser format - designed to succeed the
digital versatile disc (DVD) - will feature up to 27 GB of
memory on one side of a single 12-cm disc, nearly six times
the capacity of current 4.7 GB discs, and could store approximately
40 hours of ordinary television broadcasts as well as more
than two hours of digital high-definition motion pictures.
Discs using the new format are expected to be the same size
as compact discs and DVDs.
Cree, Inc. of Durham, NC, believes its blue laser diodes
will have specifications suitable for the recently announced
uniform standards for this next-generation optical disc format.
The company started sampling its blue laser diodes in December
2001. Evaluation is currently underway at major electronics
DVD manufacturers. Also, Cree recently announced that the
405 nm, 3-mW blue laser diodes exhibit a projected lifetime
exceeding 10,000 hours at room temperature.
Because blue and ultraviolet (UV) lasers have a shorter wavelength
than red lasers, they may also benefit optical storage systems
by enabling them to read and write more bits of information
on any given area of disc space.
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NEW TECHNOLOGY PROVIDES ELECTRONIC CORRECTION FOR LASER WRITING
SYSTEMS
Using multiple laser beams that simultaneously write several
scan lines can increase the speed of a laser writing system.
Whether you write with one laser beam or multiple laser beams
its position and final location on the writing plane is subject
to mechanically induced aberrations. These irregularities
result from the commonly used revolving polygon mirror. When
using only one laser beam these aberrations can be optically
corrected by a lens system. The use of multiple laser beams,
however, does not allow for optical correction because every
beam has a slightly different angle.
This technology from AGFA proposes electronic correction
as an alternative; therefore, allowing multiple laser beams
to be used for simultaneous writing at the correct location
of the image plane. This technology is especially relevant
for any laser writing system where speed is essential.
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A NEW FAMILY OF HIGH POWER CW LASERS
These continuous wave (CW) DWDM lasers from JDS
Uniphase (San Jose, CA) offer cost savings for next-generation
metropolitan and long haul architectures. The CW lasers also
provide the high performance needed by the emerging market
for wavelength specific solutions in CATV networks.
The new lasers are offered in 40- and 50-mW versions without
internal wavelength monitoring and a 40-mW version with an
integrated wavelength monitor. The devices feature relative
intensity noise (-160 dB/Hz maximum), narrow linewidth (1
MHz maximum), side-mode suppression ratios (typically 45 dB)
and thermal stability (wavelength drift with case temperature
better than 0.0001 nm/ degree C for the CQF975/708). The lasers
are available at ITU 50 GHz for the entire C and L band and
offer built-in thermoelectric coolers, and polarization maintaining
fiber.
JDS Uniphase's family of CW sources lasers now includes 2.5,
10, 20, 40 and 50-mW WDM lasers and 40-, 50-, and 63-mW TDM
lasers.
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WORLD'S FIRST INDUSTRIAL Q-SWITCHED CO2 LASER
Combining ultra-short, high-peak-power pulses with a rugged,
sealed package, the GEM Q-400 is suited for drilling and micromachining
applications. Coherent-DEOS, a member of the Coherent
Photonics Group (Santa Clara, CA) featured the DIAMOND(tm)
GEM Q-400 at Photonics West in January 2002.
The GEM Q-400 produces 15W average power at 50 kHz repetition
rate and 9.25 microns wavelength. It features 2.5 kW peak
power with pulse widths controllable to less than 150 ns,
peak pulse energies to over 400 microjoules, and repetition
rates to 150 kHz. These characteristics are particularly important
for applications such as PCB microvia drilling, where current
laser techniques leave charring or residue on the circuit
board. GEM Q-400's combination of narrow-width, high-energy
pulses, high rep rates, and a wavelength well-matched to PCB
dielectric materials allow it to process cleanly and precisely
without leaving any residue behind.
With its RF-excited waveguide oscillator sealed in an all-metal
housing, the GEM Q-400 has been optimized for demanding manufacturing
environments. The unit has an expected field lifetime of more
than 15,000 hours.
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