Results 1 to 5 of 5

Thread: Analog modulated laser that scans dashes!

  1. #1
    Join Date
    Nov 2008
    Location
    Cleveland Ohio
    Posts
    2,414

    Default Analog modulated laser that scans dashes!

    Any idea why a 532nm laser called an analog modulated laser would breakup into dots and dashes. On the pangolin ILDA pattern the 50% white grid is a 50% dash and 50% blank. I'm betting this is really a PWM laser! or.....is the power supply set in correctly in the driver.

    I'd like to try and scrap the driver and replace it with a teamwavelenght driver. They get 1 mhz bandwidth and work great on my diodes. Problem is figuring out the requirements for the drive diode.

  2. #2
    Join Date
    Apr 2006
    Location
    Orlando, FL - USA
    Posts
    1,767

    Default

    Hi Kecked,

    Great to see you here!

    What you are describing is what I call "jelly beaning", because instead of the laser making a solid line, it makes a bunch of dashes that look like jelly beans lined up end-to-end.

    It COULD be a driver problem, but more liklely is a problem within the laser itself. During ths past summer, we did a lot of research into this. The research ended in some driver designs that haven't been made public yet, and a laser protection device which has been made public (LASORB).

    But regarding "jelly beaning", what we found is that in most cases this is a phenomenon caused by (and experienced by) the pump diode. In a few cases, we were able to solve it by replacing the pump diode with one of higher quality. But in other cases, this did not solve the problem.

    Normally, in order to solve this problem, the pump beam must be optically isolated from laser interaction at the wavelength of interest. This optical isolation involves multiple optical components and thus, additional cost and alignment. Many lasers in the world (especially Chinese lasers) do not have such an isolator, but of course these are also the least expensive types...

    While researching this, I came up with an idea to isolate the pump from the laser action in a very inexpensive way. Bridge (of LaserWave) is looking into this to see if my idea works or not.

    So, bottom line, I am not sure that your problem is solvable. You could try a new driver, but if that doesn't help then, depending on the laser, you may not be able to get to the optcal components to improve the situation.

    Best regards,

    William Benner

  3. #3
    Join Date
    Nov 2007
    Location
    Cairns, Australia
    Posts
    1,896

    Default

    I thought jellybeaning was referred to mode hopping, but I giess that isnt the case.

    Wouldnt something like a high efficiency green blocking filter infront of the pump diode fix that problem well enough, or am I missing something?

  4. #4
    Join Date
    Nov 2008
    Location
    Cleveland Ohio
    Posts
    2,414

    Default jellybeans

    Great to see you as well Bill. In some ways I wish it was controllable as it is an interesting affect on some abstracts. It is like a really high req chopper!

    I bought a new laser from bridge. Maybe I'll get lucky with the new one. Sans that I go back to the aom.

  5. #5
    Join Date
    Nov 2008
    Location
    Cleveland Ohio
    Posts
    2,414

    Default laserwave laser

    I got the new laser and so as to complete this thread I thought I'd say it works VERY WELL. I recommend his lasers.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •