Multi-Spectral laser driver

[abikutn]

Hi,

I am doing a multi-spectral experiment.

I have 4 different 5.6mm lasers : 445nm, 405nm, 638nm, 655nm.

The input to these lasers is a pulsed TTL signal running at 80Mhz. I want a pot on the driver so that I can calibrate the current at the output side , so that I can make sure all the 4 lasers are working at the optimum level.

Please advise me where I can buy one such board. The RISE and FALL time needs to be good else the pulse shape wont look as original.

The Maximum current needed on the output will be no more than : 150mA ,and ,

Maximum input voltage range will be : 0-5.5V

The DataSheets for the lasers I am using is attached with this post.


Please advise ... Thanks ...

 

[Bionic-Badger]

Um, TTL modulated at 80Mhz? You'll probably need something like an acousto-optic modulator to achieve that.

 

[abikutn]

Um, TTL modulated at 80Mhz? You'll probably need something like an acousto-optic modulator to achieve that.

How about LVDS ??? Its possibly better than TTL right ?

 

[Bionic-Badger]

I'd worry more about the modulator you're going to use, and less about the signaling voltage levels it uses.

 

[Hiemal]

... 80 mhz is almost FM band frequency. You're going to be hard pressed to find a driver that can do that cheaply.

 

[phenol]

Any reason 50MHz won't work? 50kHz? DC?
fidning/building a driver with response time of a few ns is one part of the problem, the other is how you are going to apply the signal to the diode in order to eliminate impedance mismatch and reflections (electrical, not optical) that would cause overshoot and possibly damage something.

 

[abikutn]

Any reason 50MHz won't work? 50kHz? DC?
fidning/building a driver with response time of a few ns is one part of the problem, the other is how you are going to apply the signal to the diode in order to eliminate impedance mismatch and reflections (electrical, not optical) that would cause overshoot and possibly damage something.

I agree ... That is the exact problem I am breaking my head on ... The rate at which I pulse the LD is the problem ... Impedance mismatch is a one thing that worries me ...

:tired:

 

[abikutn]

what do you guys think about this LD driver board ...

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CDIQFjAA&url=http%3A%2F%2Flaserpointerforums.com%2Fattachments%2Ff67%2F40946d1361489586-laser-driver-purchase-hg_datasheet_a2en.pdf&ei=roQ3Uc2kJIfa2QWk7YD4Dg&usg=AFQjCNG1fS4aLyyq9XXOBoudSwk3gCFPaQ&sig2=CctO24wpUPGh-m56Ka4UXA&bvm=bv.43287494,d.b2U

 

[abikutn]

Any reason 50MHz won't work? 50kHz? DC?
fidning/building a driver with response time of a few ns is one part of the problem, the other is how you are going to apply the signal to the diode in order to eliminate impedance mismatch and reflections (electrical, not optical) that would cause overshoot and possibly damage something.

As for your question on driving frequency ...

The input to the LD is a pulsed TTL (0-4.8v) input from a data-generator , we can reduce the rate but the sampling rate wont be good ... This pulsed input signal is basically CDMA coded so that we can identify the final Image and separate them based on each wavelength ( remember I said these 4 lasers are used in confocal imaging , so each final RAW Image corresponds to one wavelength ) ... The higher the frequency the better the sampling rate and thus better the Image detail ...

 

[phenol]

Thats a neat driver,but the max supply voltage of 5.5V may not be sufficient for it to drive the violet and blue diodes. The drivers found in bluray burners should do the trick. Either way, layout is supercritical and i'd try to get the eval board if i were you. Also, if diodes should be located some distance away from the board, you should use microstrip lines of a couple of ohms like those in dvd/bluray burner sleds.
alternatively, you could dc bias the diode thru rf decoupling chokes and then AC couple on top of that RF modulation. This wont be on/off modulation, though

 

[hakzaw1]

No opinion about the driver but you need to combine those three posts and refrain form double posting- copy #9 & 8 ( and paste them in #7)
do that &
fill out your personal profile
& I will post a driver that will run three diodes.

************ BTW

you have been here more than 4 months- when do you intend to make your introduction thread in the WELCOME section??
Its considered good manners-especially if you have a lot of questions you want answers to... just saying.

(& the best way to show appreciation is an occasional small donation)

 

[abikutn]

No opinion about the driver but you need to combine those three posts and refrain form double posting- copy #9 & 8 ( and paste them in #7)
do that &
fill out your personal profile
& I will post a driver that will run three diodes.

************ BTW

you have been here more than 4 months- when do you intend to make your introduction thread in the WELCOME section??
Its considered good manners-especially if you have a lot of questions you want answers to... just saying.

(& the best way to show appreciation is an occasional small donation)

hakzaw1 : Right away sir