[Laser] Laser diode checkups

[F1AVYopto at aol.com]

Dans un e-mail daté du 12/01/2006 20:56:11  Paris, Madrid, jlinden at sjm.com a 
écrit :
Sharp LTO17MDO 50 mW laser  diodes

To test an unknown laser diode is not easy.
Do you know  the case wiring to locate the internal PIN photodiode (if there 
is one) and the  laser diode before to test? 
If not, you have to identify the wires before  with a homemade tester.
Use a 1,5V battery (max!) in serial with a 1 mA galva  (or current 
controller), a 1 K resistor and put a 1N914 diode in reverse between  this loop two-test 
points.
Identify the test point’s polarities.
Remember  that all above 2V transient reverse voltages kill the laser diodes!
The PIN  photodiode is the lowest resistor device in direct way.
The laser diode is  highest resistor device is direct way.
When you know the laser diode wiring,  use a current generator to drive this 
diode in direct way.
For a 50 mW laser  diode the current threshold is may be about 60 mA.
The output power can be  roughly checked with a PIN photodiode locate at the 
laser diode window.
A  BPW34 give about 1 mA shortcut current for 5mW on 780 nm. 
Remember that the  smallest over current always kills the diode and also...50 
mW is a dangerous  laser power...
You can find some other elements on my Internet site at  :
http://pageperso.aol.fr/YvesF1AVY/UK2.html 
I am sorry for my poor  English.
73 Yves.
http://pageperso.aol.fr/YvesF1AVY/UKINDEX.html