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10-29-2009, 06:08 PM #1
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Meatball
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Regressional Analysis for LD Characteristics

With a whole slew of new blu-ray diodes coming from new drives, being used in new builds, I think it would be a good idea to regather all of these diodes and their graphs into one place. If I were to start a new thread in the general section, that graphed and attached a function to the normal behavior of laser diodes would that lift a lot of the "How much current" threads that are started by new members?

Similar to Dr. Lavas diode roundup, I would like to make a master graph for all reds and blu-rays that we work with. This graph would plot the mathematically averaged results seen from every diode.

So for the plot on the graph that represents what a BDR-203 typically lases in terms of input current vs. its optical power output, I would have to find an average for all the plots seen on FrancoRobs master 8X graph for instance.

I would gather as many graphs as possible from the forum, that plot someone's BDR-203 (or whatever else diode). I would then re-plot them into my graphing program, and use regressional analysis to find a "best fit curve". The program would then give me the equation for this best fit function.

From there, we could use that function, the universally determine what a typical example of a given diode will lase.

... IF I could get diode voltages for the same graphs, then I would go ahead and make efficiency functions for the universal diode. Which would determine the power efficiency of a diode at given currents.

I know LDs are so different in many ways, but to have a function to work with would be valuable to have for every diode we work with.

Hopefully Dave, Igor, and Larry can get in on this too...

collecting the data will take some work!

Tell me what you ALL think..

Could this be beneficial to the forum? Who would be willing to help collect data?

Thank you,

-Tyler

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10-29-2009, 06:14 PM #2
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Re: Regressional Analysis for LD Characteristics

10-29-2009, 08:05 PM #3
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Meatball
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Re: Regressional Analysis for LD Characteristics

Lets work together then!

For the plots, I think it might be effective to depict "conservative current" ranges, and "recommended long life current" ranges, and "short life current" ranges by making the line a different color in different areas.

The green part of the line would be on lower current levels, the yellow part on higher levels, and so on... just an idea.

I think LarryDFW is working on determining "safe" current ranges for just about every blu-ray diode out there.

What software do you have to plot with?
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10-29-2009, 08:31 PM #4
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nikokapo
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Re: Regressional Analysis for LD Characteristics

Quote:
 Originally Posted by Meatball Very good! I'm glad to see someone as eager about this as I am! Lets work together then! For the plots, I think it might be effective to depict "conservative current" ranges, and "recommended long life current" ranges, and "short life current" ranges by making the line a different color in different areas. The green part of the line would be on lower current levels, the yellow part on higher levels, and so on... just an idea. I think LarryDFW is working on determining "safe" current ranges for just about every blu-ray diode out there. What software do you have to plot with?

Comparative graphs would be great, I think Conservative/Performance/Max current graphs should be done to allow members to determine what they want.

I don't have the hardware needed to do testing, I can only plot with Excel, though I have learned to use "Origin" last week in Physics II (nothing special, I'm not good a it since I have never used it since that class and probably never will). If you have good software + practise on plotting then I'd rather you do them if you have the time (and if you're willing to). If not just give me the data and I'll plot them in Excel and save images as .png's.

Gotta go to take a Final, PM me if you need to discuss this further.

11-02-2009, 03:53 PM #5
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Re: Regressional Analysis for LD Characteristics

nikokapo;

maximum power outputs that various manufactuers have released.

The current levels and graphs are in this thread:

Blu-Ray Current Levels Long-Life

I am waiting for more data from Igor to fine-tune the results.

From Dr. Lava's testing, it looks like my operating levels are ~70% of the failure points of some diodes.

LarryDFW

Last edited by LarryDFW; 11-02-2009 at 03:58 PM.

11-02-2009, 04:00 PM #6
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Meatball
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Re: Regressional Analysis for LD Characteristics

Thanks Larry,

This will be helpful for when I develop the proper functions for each diode.

Btw, if you have any Excel files with ANY diode data for any diode, we could use them!

PM me for my email if you have any files you'd be willing to share.

Thanks,

-Tyler
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11-02-2009, 04:09 PM #7
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nikokapo
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Re: Regressional Analysis for LD Characteristics

Thanks a lot for the help, we really need it

Head over here if you want to look at how the thread takes shape:

Diodes Compilation - All Diodes Data In One Thread!

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