Black Weekend. I lost three 445 diodes!

just thought I'd quote myself from an earlier post, the point being that generally all Flexmods should perform similarly:

ElektroFreak said:

I've put mine on my scope and I always see a very small voltage/current spike on power up, but the current always ramps up nice and smooth under modulation, no spikes there. The initial spike *could* be causing premature degradation, but it's not a very big spike so I don't know for sure.

Click to expand...

however the fact that you are using an older FlexMod leaves me at a loss. Are you driving multiple diodes with a single driver?

Coherent Light said:

could you not install a filter cap on the output just to be on the safe side?

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That would screw with the modulation, especially at high speeds.

ElektroFreak said:

just thought I'd quote myself from an earlier post, the point being that generally all Flexmods should perform similarly:



however the fact that you are using an older FlexMod leaves me at a loss. Are you driving multiple diodes with a single driver?

Click to expand...

Yes, At first I had 2 diodes in series. 1.2A 10V. It had been running for many, many hours without any issues...see my avatar.

After they both popped I used a single diode...which also blew after modulation.

The conclusion: (thanks for all the input from you guys)

I'm going to buy this driver for ebay

High Power Laser Diode Driver for Shows: Red Green Blue - eBay (item 200542526302 end time Jan-10-11 22:43:54 PST)


then, I'll hook it up to another 445 (I have 4 left) and MODULATE. Using 100mA as threshold.

BTW, the reason I has it on 0.01A as threshold was because the laser "glows" brighter as you add more and more mA's. It's annoying. When I'm not modulating I want the laser to be OFF. But in this casue the laser is always ON (even it it's not lasing). I may have to include a shutter in my system.

Will let you guys know.

B


Forgot to tell you... Before I did the whole modulate-blow-laser thing, mixing 1 watt green with 2+ watt blue gave an almost white light. It was incredible. When I mixed the 1 watt blue with the green I got this amazing turquoise blue...I'm guessing the similar colour as the 473 line.

The driver in your link is actually the new Flexmod P3..

ElektroFreak said:

The driver in your link is actually the new Flexmod P3..

Click to expand...

I'll have to try it........thx

UPDATE: 20 FEB 2011

My two new Flexmod P3 have arrived and sitting in customs. Should have it before the weekend.

Going to try modulate another 445nm and hopefully it doesn't kill it. Will post results....

3 diodes in one weekend? $150 ouchies....

Better luck on the next try!

RIP as i try to build my own 445nm

I have my two new Flexmod P3's. As per all the excellent advise on this forum, my 300mw 660nm volunteered for possible death by modulation. I'll modulate it between 20mA-300mA.
If he survives I'll hook up the 445nm.....

The short answer. SUCCESS!

Last night I connected a 445nm to the Flexmod P3. Threshold 150mA, Max 1.4A.
I first I ran the modulation at 1K pps on the software. This resulted in a random flashing of the laser. After awhile I increased it to 45K PPS which produced a steady beam with very little flicker. I ran it at this speed for 30 minutes.

Conslusion. It does look like my older N2 Flexmod cause the death of the 3 diodes.