How to control laser by computer

[Dean86]

Hello,

I'm a student and for first time I'm having an approach with this kind of problem.

I have to control a diode laser by computer, so now my question is, what kind of device I have to use between the computer and the laser?

How can I link this device with the computer and the laser?

What kind of interface I have to use?

The idea is to use Labview.

Thank you very much for your time.

Regards.

[crossrulz]

What is the model of the laser?  What interfaces does the laser have?  You just haven't given any information for us to help.

[Dean86]

I know and I'm sorry but I told you, it's first time that I have to approach to this subject.

About the type of laser, I think about a GaAs/GaAlAs diode laser, I need it for a wireless comunication in free space between 2 buildings, something like 30/40m. About the wavelenght, maybe 1060nm which gives low atmospheric scattering. About the interface, I saw that the most of this kind of laser use a BNC connector.

I hope now I gave enough information, if not, I'm sorry, ask me what else.

Thank you again.

[crossrulz]

A BNC connector means next to nothing.  What is the protocol used to communicate with the laser?  Ethernet (yes, I have seen Ethernet through BNC connectors)?  Straight digital pulses?  High voltage pulses?  If you don't know what interfaces the laser uses, you can't do anything with it.

[Dean86]

Ok, maybe I should ask you for first, what kind of laser you suggest me for this kind of situation, 2 buildings, 10m-50m of distance. Could you help me in this? 

Thank you.

[AnalogKid2DigitalMan]

We need the manufacturer and model number of the diode or post the specs to provide any further help.

If it has some type of BNC or SMA connector, that may suggest it is a laser diode/driver module with a modulation input for a digital signal.

Diode lasers need a constant current source and power monitor control loop, they can easily be damaged by too mucg current or voltage.

-AK2DM

[Dean86]

So, if I want to use this kind of laser, what should I do to control it by PC?

[crossrulz]

First thing you have to do is pick a laser that will meet your specifications.  Once you figure that out, then come to us and we will help you talk with it.

[johnsold]

It almost sounds like the OP is talking about a "bare" laser diode. If that is the case, you will need a driver circuit which is matched to the characteristics of the laser diode and designed to operate at the communication rates you want to use.

It seems that you hardly know what questions to ask.  As a student it is your responsibility to understand your assignment and to break down the problem into smaller segments until you reach the level where you know how to do each segment.

You have been asked several times.  Your homework assignment to get a passing grade and more assistance on this Forum is:

1. Identify the laser diode and any drivers, apparatus, or equipment associated with it.

2. Determine the input and output characteristics of the devices in item 1.

3. Define the type of communication protocol you want to use. If this is too complicated at this level, define the types of signals you wish to transmit.

Report back here with this information and send a copy to your instructor.

Lynn

No, I am not a professor, but I have taught engineering.

[Dean86]

Thanks, I appreciate your suggestion.

Of course I want to understand what I'm going to do, the problemi is that no one's giving me enough information (I mean about my university).

I will try to fix this 3 points and I'll answer again as soon as possible.

Thanks again.

[johnsold]

No one meant any personal criticism but we see many school enrollees (they should not be called students because that word implies studying) who want someone else to do all their work for them.

When you get to the level where they expect you to be able to handle open ended assignments like this, part of the task is to gather the necessary information.  In the real world you never get assingments like those in elementary school: Do the odd numbered exercises at the end of the chapter. Assignments are always somewhat vague and incomplete.

Asking questions is a good way to start and the more specific the questione, the more likely the answer will be useful.

Also try a literature search to see what has already been done.

Lynn