Help if possible on laser project

[CurtisOliver]

The chances of using those diodes in your application is very unlikely.
No single and multi-mode is a reference to longitudinal modes and does not make much difference to wavelengths.
A single mode laser has a single emitter whereas the multi-mode has multiple.

Single modes work better with fibre cables as their beam specs are inherently better.

 

[jimmy433]

Ah cheers so it focuses mainly around the idea of the beams of light being emitted

 

[CurtisOliver]

Yes, you ideally want one single emission for the fibre cable.

 

[paul1598419]

Wow. This thread has taken on a life of its own. I haven't posted here past my last post concerning the use of two single mode diodes. It seemed pointless to continue and there were more members who were willing to continue to beat this dead horse. I guess it will further continue until it finally dies a proper death.

 

[CurtisOliver]

Most likely.

 

[diachi]

A single mode laser has a single emitter whereas the multi-mode has multiple.

That's actually wrong ... Multi-mode refers to the number of resonator modes (transverse/longitudinal), not the number of emitters. The first diagram you posted shows the wavelength distribution of the different resonator modes, which are all slightly different in wavelength from the center wavelength.

Multi-emitter lasers have multiple emitters, such as the LD array in your second picture. There's no reason an LD array couldn't have multiple single mode emitters. They are however, generally speaking, high power multi-mode emitters. Usually each emitter will be combined to its own fiber which is placed into a fiber bundle.

Common 19 emitter diode array coupled to individual fibers/fiber bundle:

While true that coupling a single mode beam to a fiber would be easier, it's not impossible with a multimode beam, it would just result in higher insertion losses. Initial power is also higher, so while it may be less efficient to couple a multi-mode beam overall, output power could still be higher than with a single mode source.

:beer:

 

[CurtisOliver]

Thanks for pointing that out Diachi. I actually edited changing transverse to longitudinal. I always get them mixed up for some reason.
Also why did I confuse multiple emitters :thinking: I'm having one of those days today. :beer:

 

[diachi]

Thanks for pointing that out Diachi. I actually edited changing transverse to longitudinal. I always get them mixed up for some reason.
Also why did I confuse multiple emitters :thinking: I'm having one of those days today. :beer:

Sounds like you need some coffee and some R&R. :beer:

 

[CurtisOliver]

Yes, definitely. I've said this before to others so I know that I do know it. :bang head: Been a bit distracted today. Had the police see me about what has happened lately.

 

[diachi]

Yes, definitely. I've said this before to others so I know that I do know it. :bang head: Been a bit distracted today. Had the police see me about what has happened lately.

Yeah, I remembered you had a lot on your plate atm. Hope it all gets worked out ...

Anyway, don't want to derail too much.

 

[CurtisOliver]

Thanks Diachi. :beer:
Back on topic again.

 

[jimmy433]

Hey guys so iv got a basic schematic of the device here, im thinking of implementing the TEC system shown maybe doing a joint one, do you think the diodes will heat up that much? or would a heatsink+host/module be enough. Also do you guys know a good laser driver i could use for the LPC836 with the power supply?

 

[paul1598419]

I'll give this one more try. You have an LPC-836 diode which outputs up to 400 mW of optical power in a very tight beam because it is a small emitter coupled to the highest power 520nm green LD with muliple emitters in a single axis that is capable of over 1 watt of optical power. The green output is more visible to us because of its wavelength per mW of power when compared to the 650nm output of the red diode. Because the emitters don't match and because the outputs have the green probably three times the power of the red, the green will wash out the red and you will have a mismatch in the beams divergence. Because the green wavelength is so much more visible to us than the red one, you could use a smaller emitter green diode at a lower power than the red to get, not only a better match in beam divergence, but also a better color match between the two colors.

 

[CurtisOliver]

Nice try Paul. I don't know how many times this needs to be explained in various different ways.
He has already stated that the diodes can't be changed. :thinking:

 

[ArcticDude]

Ok, I will also try once more..
I really trying to say this as polite as I can:

Atm you are climbing in the tree your arse upwards. Or at least trying to
(Speaking in a descriptive way)


Everything I've seen is exact opposite of my understanding of any kind engineering.

I cant sense any notable planning or scheming, or calculations of any kind. -Project management is poor and you are rushing over here and there.
I havent seen any figures or numbers that show that your device is can be done even in bluepaper.

If you had studied this subject even little bit, you probably had discovered that this kind of applications / devices have been engineered many many years a go.
Manufactures and scientific / lab companies does already know benefits and limitations of these kind of applications or devices. -As paul and Diachi metioned.

http://opticalengineering.spiedigitallibrary.org/article.aspx?articleid=1158345

http://www.sukhamburg.com/products/RGBV_Laser_beam_combiner.html

http://www.directindustry.com/prod/oxxius/product-62774-1594289.html


No educational instance, nor any company will provide these "Magically free" NDG7475 diodes for students / person. Even more for person/students who does not have essential knowledge of lasers or needed skills of engineering.

Plus, All this for the application which wont be used in any "practical sense" as you stated.

keep in mind this probably wont be used in any practical sense, it is to just mainly experiment to see if we can use these diodes in this kind of application.

If educational level for engineering is kind of that level in your country (what you have shown us), I really hope that there's no nuclear facilities anyway near.

Study more, imagine less.

 

[Alaskan]

Cruel dude, showing me a photograph of such a sublime instrument like that, I'm drooling, nice laser. Now about climbing that tree, turn the other way around, much easier and doable!