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Jon Slaughter
Guest
Tue Mar 09, 2010 8:36 pm
What does a diode laser module add to a diode laser? A voltage regulator or
current limiter?
Jon Slaughter
Guest
Tue Mar 09, 2010 9:26 pm
Wanderer wrote:
Quote:
On Mar 9, 2:36 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
What does a diode laser module add to a diode laser? A voltage
regulator or current limiter?
A laser diode usually has a built in photodiode for constant power
control. A simple module would provide the trans-impedance amplifier
in a loop with the laser to provide a voltage in to light power out
conversion. More complex modules would have additional features like
temperature control.
So when exact intensity control is not needed one can simply use a resistor
a.k.a. the basic method used for current limiting led's?
ian field
Guest
Tue Mar 09, 2010 10:04 pm
"Jon Slaughter" <Jon_Slaughter_at_Hotmail.com> wrote in message
news:hn6atd$rjm$1_at_news.eternal-september.org...
Quote:
Wanderer wrote:
On Mar 9, 2:36 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
What does a diode laser module add to a diode laser? A voltage
regulator or current limiter?
A laser diode usually has a built in photodiode for constant power
control. A simple module would provide the trans-impedance amplifier
in a loop with the laser to provide a voltage in to light power out
conversion. More complex modules would have additional features like
temperature control.
So when exact intensity control is not needed one can simply use a
resistor a.k.a. the basic method used for current limiting led's?
That's all cheap laser pointers have, but I'd reccomend a decent current
regulator circuit - as someone else pointed out, lasers can be a bit
fragile.
Wanderer
Guest
Tue Mar 09, 2010 10:12 pm
On Mar 9, 2:36 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
Quote:
What does a diode laser module add to a diode laser? A voltage regulator or
current limiter?
A laser diode usually has a built in photodiode for constant power
control. A simple module would provide the trans-impedance amplifier
in a loop with the laser to provide a voltage in to light power out
conversion. More complex modules would have additional features like
temperature control.
George Herold
Guest
Tue Mar 09, 2010 10:44 pm
On Mar 9, 3:26 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
Quote:
Wanderer wrote:
On Mar 9, 2:36 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
What does a diode laser module add to a diode laser? A voltage
regulator or current limiter?
A laser diode usually has a built in photodiode for constant power
control. A simple module would provide the trans-impedance amplifier
in a loop with the laser to provide a voltage in to light power out
conversion. More complex modules would have additional features like
temperature control.
So when exact intensity control is not needed one can simply use a resistor
a.k.a. the basic method used for current limiting led's?
Yup, a current source will work fine. I don't think module is well
defined when it comes to diode lasers. I would assume that the module
has the collimating lense. Where a bare diode would not.
Speaking of diode lasers we just made a 'lifetime' buy of DL-7140's
from Sanyo, last production run. These lase near 780nm are are great
for Rubidium stuff.
George H.
Darwin
Guest
Tue Mar 09, 2010 10:50 pm
On 9 Mar, 21:26, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
Quote:
So when exact intensity control is not needed one can simply use a resistor
a.k.a. the basic method used for current limiting led's?
There are two reasons. The first one is that laser diodes are rather
fragile components. Now, it depends on the particular laser diode you
are using, but the situation was way worse in the past. The second
reason is that the lasing threshold is very much temperature dependent
and if the system is exposed to temperature changes. For example, the
current which provides the nominal output power let's say at 25°C can
be dangerous at a lower temperature, since the threshold has decreased
in the meanwhile.
I have seen a resistor (or even the internal resistance of the
batteries) limiting the current in very cheap laser pointers but I
would not go on that system for any serious laser use.
Wanderer
Guest
Tue Mar 09, 2010 11:03 pm
On Mar 9, 3:26 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
Quote:
Wanderer wrote:
On Mar 9, 2:36 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
What does a diode laser module add to a diode laser? A voltage
regulator or current limiter?
A laser diode usually has a built in photodiode for constant power
control. A simple module would provide the trans-impedance amplifier
in a loop with the laser to provide a voltage in to light power out
conversion. More complex modules would have additional features like
temperature control.
So when exact intensity control is not needed one can simply use a resistor
a.k.a. the basic method used for current limiting led's?
If you're just working with one laser yes. You need to set the current
above the threshold. But the power output will vary a lot from laser
to laser and with temperature. Odds are the laser will get hot and
die. The voltage drop of a laser diode is very temperature sensitive.
The TIA circuit is very simple you can do it with one dual opamp. One
opamp act as the TransImpedance Amplifier and the other act as a
difference circuit. I don't know what laser you are trying to use but
for many of the smaller ones available at digikey an LF353 is good
choice for this circuit. If you need more current you can add a
transistor to the driver.
nospam
Guest
Wed Mar 10, 2010 12:00 am
"ian field" <gangprobing.alien_at_ntlworld.com> wrote:
Quote:
That's all cheap laser pointers have, but I'd reccomend a decent current
regulator circuit - as someone else pointed out, lasers can be a bit
fragile.
Lol.
Last one I did a driver for datasheet rated maximum power 10mW, absolute
maximum power 11mW for 10uS.
Jamie
Guest
Wed Mar 10, 2010 2:06 am
Jon Slaughter wrote:
Quote:
What does a diode laser module add to a diode laser? A voltage regulator
or current limiter?
Current regulation is very important.
Joerg
Guest
Wed Mar 10, 2010 2:42 am
Wanderer wrote:
Quote:
On Mar 9, 2:36 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
What does a diode laser module add to a diode laser? A voltage regulator or
current limiter?
A laser diode usually has a built in photodiode for constant power
control. A simple module would provide the trans-impedance amplifier
in a loop with the laser to provide a voltage in to light power out
conversion. More complex modules would have additional features like
temperature control.
Not temperature control itself but they contain a thermistor, typically
a 10k version.
--
Regards, Joerg
http://www.analogconsultants.com/
"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
John Larkin
Guest
Wed Mar 10, 2010 3:15 am
On Tue, 9 Mar 2010 12:44:25 -0800 (PST), George Herold
<ggherold_at_gmail.com> wrote:
Quote:
On Mar 9, 3:26 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
Wanderer wrote:
On Mar 9, 2:36 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
What does a diode laser module add to a diode laser? A voltage
regulator or current limiter?
A laser diode usually has a built in photodiode for constant power
control. A simple module would provide the trans-impedance amplifier
in a loop with the laser to provide a voltage in to light power out
conversion. More complex modules would have additional features like
temperature control.
So when exact intensity control is not needed one can simply use a resistor
a.k.a. the basic method used for current limiting led's?
Yup, a current source will work fine. I don't think module is well
defined when it comes to diode lasers. I would assume that the module
has the collimating lense. Where a bare diode would not.
Speaking of diode lasers we just made a 'lifetime' buy of DL-7140's
from Sanyo, last production run. These lase near 780nm are are great
for Rubidium stuff.
George H.
Appointech sells us nice diode lasers and detectors. I don't know if
they do 780.
John
Guest
Wed Mar 10, 2010 3:31 am
Here, the beast of choice is the EU38 for learning.
We really do prefer constant current sources, laser diodes respond
very well to transients on resistor only supplies, often blowing the
faucet off the face of the laser diode/ diode and turning it into a
weak led.
http://www.repairfaq.org/sam/laserdps.htm
http://www.repairfaq.org/sam/laserdio.htm
A fellow I know has a patent on, and makes these, to protect the LD
against static
http://www.lasorb.com/
Lasorbs are NOT snake oil, they do what they claim.
Steve
Joerg
Guest
Wed Mar 10, 2010 3:33 am
osr_at_uakron.edu wrote:
Quote:
Here, the beast of choice is the EU38 for learning.
We really do prefer constant current sources, laser diodes respond
very well to transients on resistor only supplies, often blowing the
faucet off the face of the laser diode/ diode and turning it into a
weak led.
Oh yeah. I prefer current sources as well. For hobbyists the LM317
rigged as a current source should do quite well. It's a well-behaved
regulator.
Quote:
Although I often couldn't live with the large capacitance. So far I have
not destroyed one, and I've worked with quite a few including some in
the four-digit a piece price range. As long as the current source can
never ever spike and there's a reverse diode protection most situations
are ok.
--
Regards, Joerg
http://www.analogconsultants.com/
"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
George Herold
Guest
Wed Mar 10, 2010 9:02 pm
On Mar 9, 9:15 pm, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
Quote:
On Tue, 9 Mar 2010 12:44:25 -0800 (PST), George Herold
ggher...@gmail.com> wrote:
On Mar 9, 3:26 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
Wanderer wrote:
On Mar 9, 2:36 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
What does a diode laser module add to a diode laser? A voltage
regulator or current limiter?
A laser diode usually has a built in photodiode for constant power
control. A simple module would provide the trans-impedance amplifier
in a loop with the laser to provide a voltage in to light power out
conversion. More complex modules would have additional features like
temperature control.
So when exact intensity control is not needed one can simply use a resistor
a.k.a. the basic method used for current limiting led's?
Yup, a current source will work fine. I don't think module is well
defined when it comes to diode lasers. I would assume that the module
has the collimating lense. Where a bare diode would not.
Speaking of diode lasers we just made a 'lifetime' buy of DL-7140's
from Sanyo, last production run. These lase near 780nm are are great
for Rubidium stuff.
George H.
Appointech sells us nice diode lasers and detectors. I don't know if
they do 780.
John- Hide quoted text -
- Show quoted text -
Thanks John, these were just the bare diode used in Cd players. We
get them for ~$15 each. If we every run out of the 300 we have on
hand and the 400 we have on order then I'll have to go searching.
George
Jon Slaughter
Guest
Thu Mar 11, 2010 12:43 am
Jon Slaughter wrote:
Quote:
What does a diode laser module add to a diode laser? A voltage
regulator or current limiter?
How do I determine the working current from the datasheet? I have an OPV322
that I ran from about 3mA to 5mA. The datasheet says the max is 12mA(Maximum
Forward Peak Continuous Current) and the threshold is 3mA. It says the min
total power output is 1.5mW at If=7mA.
So I take it that the operating range is 3mA to 12mA with average of 7mA?
What I don't understand is that mouser listed this as a 5mW part and on the
datasheet it has the warning box which says 10mW and the spec says 1.5mW.
In any case it does work but I would like to get about 80-90% of the maximum
which I'm figuring is about 10mA.
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