need quick temperature controlling solution of a laser diode

Hi everyone,

I need a pulsed light source for my test bench. Originally conceived as a quick and low-cost solution, I bought a red laser diode (TO-18 packaged, CW output power of 40mW), soldered it onto a PCB, and drive the diode with a pulse generator. It worked fine.

However, I also observed small variations in both spectrum and amplitude over time. I guess it was because of the absence of a temperature controller. However, I don't know how to build that part. Right now I have several TE coolers off my hands, which look a little bulky compared with the diode. Even though somehow I mount the diode onto the TE cooler (which I am not sure if I can), a feedback control is needed to stabilize the temperature to some value. Could anyone help give some hints? Thanks very much.

SpringerLink temp stabiliz of laser diode

Does the laser have a built in monitor diode? If so, you should be using that to stabilize the laser operation.

Keith

No, I don't think this diode has a thermal control pin.

---------- Post added at 16:58 ---------- Previous post was at 16:56 ----------

Thanks. I my case, do you mean I can probe and stabilize the temperature of the metal package instead?

I meant a built in photodiode - the normal way of controlling lasers.

Keith

Oh yes, it does have a built photodiode. The datasheet of this laser diode is here http://www.opnext.com/products/pdf/o...362mg_63mg.pdf

How can this pin be used to stabilize the laser diode output? Thanks.

In which case that is how you would stabilise the laser characteristics. If a laser has a built in monitor photodiode then you should always us it. As they warm up the threshold current changes. You would normally run a laser at a specific optical power. A control circuit using the photodiode would adjust the current to compensate for the temperature changes. There are chips around to do laser control if you do not want to design your own circuit, e.g. from iC-Haus.

Keith.