Sharp's New Semiconductor Laser for Triple- and Quadruple- Layer Blu-ray Discs

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A cross-sectional image of the semiconductor laser with an aluminum oxynitride film.

(PhysOrg.com) -- Sharp Corporation has announced the development of a new 500 mW semiconductor laser for triple- and quadruple- layer Blu-ray discs.

Sharp announced its new development in Japan earlier this month, at the Japan Society of Applied Physics' 70th Autumn meeting.

The semiconductor laser is blue-violet, producing an optical output up to 500 mW and 405 nm wavelength of oscillation under pulsed operation. The new laser has been proven reliable over 1,000 hours of testing.

The device is designed to be used in Blu-ray Disc recorders, and can write at 8 x speed on both triple- and quadruple- layer discs. This would mean recordable discs (with 25 GB per layer at present) to be 75 or 100 GB. The development follows the mass production of a 320 mW blue-violet semiconductor laser starting in June this year. The 320 mW device can write at 8 x speed on single- and dual- layer discs.

The optical output of the laser was improved by changing the way the edge of the semiconductor laser crystal is processed. Previous devices have covered the semiconductor laser crystal with a non-crystalline film, but this method allowed heat to degrade the crystal and eventually stop oscillation. The new process uses an AION (aluminum oxynitride) crystalline coating between the dielectric film and the semiconductor crystal's edge face. This allows the laser output to be increased.

Sharp announced it is ready to produce the new semiconductor laser, but is holding off until triple and quadruple layer disc specifications are settled.

© 2009 PhysOrg.com

   

• El_Nose - Sep 18, 2009
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  Can we all agree to an end to the format wars -- Please -- we as consumers, DVD movie buyers have no need for more density, only data storage and redudndancy care about this. And HDDVD's are more dense by far. Let it end. I do not have the money to buy my movie collection again.
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• degojoey - Sep 18, 2009
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  Umm it did end. Blu Ray won fool, get on the wagon!
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• daveib6 - Sep 18, 2009
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  And HDDVD's are more dense by far.

  
  Wrong again. HDDVD is a 15GB per layer technology with 2 layers for a max of 30GB. BluRay is a 25GB per layer technology with 4 layers for 100GB total. This is possible in part due to a thinner tougher anti-scratch coating allowing the laser to be closer to the substrate and therefore focus more tightly. Blu Ray won for a reason. It is the superior format in every conceivable way. You may as well get on the wagon because the HDDVD horse is dead. Good riddance!
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• Joeviocoe - Sep 19, 2009
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  This will probably only allow mini-disc sizes to now carry all the content of full-discs
  
  Important for hand held gaming and other portable devices.
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• El_Nose - Oct 09, 2009
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  I misspoke myself I said HDDVD -- I meant HVD Holograghic video disks
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