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Thread: Dpss lifetime question ?

  1. #1
    Join Date
    Apr 2009
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    Adelaide , Australia
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    Default Dpss lifetime question ?

    Hi all ,

    Just a quick question about lifespan hours on dpss 532nm modules .... When a manufacturer states for example 5000hours lifespan on module is this the lifespan on the pump diode or the KTP crystal or both ? .. Ive heard that the KTP can crystal can breakdown so to speak due to power below a certain wattage being pumped into the crystal causing electro chemical degredation ?

    I recently opened up a 1w viasho module and upon carefull inspection and removal of the KTP crystal it literally crumbled to bits.

    Just curious.

    Cheers,
    Brett

  2. #2
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    Jan 2006
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    Default

    I believe the MTBF rating is based on the expected lifetime of the pump diode. It's my understanding that the Vanadate and the KTP are both far more durable than the pump diode. I know several people who have replaced the pump diode in their DPSS lasers and kept the same crystals in place. I suspect the problem you experienced with the KTP in the CNI unit you had was due to some other factor, not just normal degradation.

    Note that the doubling crystals used in most blue DPSS lasers are hygroscopic, so if the cavity isn't properly purged and sealed, water vapor can get in and ruin them. (Though KTP does not suffer from this problem.)

    Adam

  3. #3
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    Quick question:

    Do you really think most Chinese manufacturers have the ability to do proper MTTF testing?

    I err on the side of probably not! and in that case I would say they quote the diode MTTF providing they are not over driving it...
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  4. #4
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    Quote Originally Posted by dave View Post
    Quick question:

    Do you really think most Chinese manufacturers have the ability to do proper MTTF testing?

    I err on the side of probably not! and in that case I would say they quote the diode MTTF providing they are not over driving it...
    I believe that Bridge properly tests this. Most diode manu's aim for 10k hours but if you check through Laserwave's catalogue they quote some as 5k some as 7k some as 10k.
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