Anybody seen a spice model for a laser diode?

[Michael]

Hi there - I was thinking about trying to design a laser driver over
the weekend. Unfortunately, I can't seem to find a spice model for a
laser diode, putting a bit of a squabash on that plan.

Anybody know where I can find one? Ideally I'd find one for a very
normal ~5mw red laser diode - like those you'd find in a cheap laser
pointer.

Thanks!

-Michael

 

[Winfield]

Hi there - I was thinking about trying to design a laser driver over
the weekend. Unfortunately, I can't seem to find a spice model for a
laser diode, putting a bit of a squabash on that plan.

Anybody know where I can find one? Ideally I'd find one for a very
normal ~5mw red laser diode - like those you'd find in a cheap laser
pointer.

I created a spice model for a purple laser diode,
complete with it's optical sensor.

 

[Hammy]

Hi there - I was thinking about trying to design a laser driver over
the weekend. Unfortunately, I can't seem to find a spice model for a
laser diode, putting a bit of a squabash on that plan.

Anybody know where I can find one? Ideally I'd find one for a very
normal ~5mw red laser diode - like those you'd find in a cheap laser
pointer.

Thanks!

-Michael

http://www.cadence.com/appnotes/ModelingPhotodiodesLEDsandLaserDiodes.zip

Heres an application note with some wxample models included.

 

[Michael]

 I created a spice model for a purple laser diode,
 complete with it's optical sensor.

Hi Winfield - out of curiosity, how would a purple laser diode differ
from a red laser diode? (besides the outputted color :0 )

Thanks,

-Michael

 

[Michael]

http://www.cadence.com/appnotes/ModelingPhotodiodesLEDsandLaserDiodes...

Heres an application note with some wxample models included.

Hi - Do you know how to import their part into LTspice? My only
experience with spice is with using the built in library components -
I've never had to work with the actual text files themselves

-Michael

 

[John Larkin]

Hi there - I was thinking about trying to design a laser driver over
the weekend. Unfortunately, I can't seem to find a spice model for a
laser diode, putting a bit of a squabash on that plan.

Does not having a Spice model stop the project dead? I wonder how TVs
and Radar were invented.

John

 

[Paul Hovnanian P.E.]

http://www.cadence.com/appnotes/ModelingPhotodiodesLEDsandLaserDiodes.zip

Heres an application note with some wxample models included.

Any good reason that I have to have Flash installed to download this?

 

[Winfield]

Hi Winfield - out of curiosity, how would a purple laser diode differ
from a red laser diode? (besides the outputted color :0 )

MUCH higher forward voltage - the band-gap voltage for
short-wavelength photons is much higher, because each
photon has much more energy. Also, every type of laser
diode will have its own plot - the laser-light output
is very nonlinear with current, and you want the spice
model to properly show that effect. Also, whatever you
get, I wouldn't trust the model until I had verified it
on the bench.

 

[Paul Hovnanian P.E.]

Does not having a Spice model stop the project dead? I wonder how TVs
and Radar were invented.

John

Someone just downloaded the application notes PDF and used an example
circuit? ;-)

 

[Helmut Sennewald]

http://www.cadence.com/appnotes/ModelingPhotodiodesLEDsandLaserDiodes...

Heres an application note with some wxample models included.

Hi - Do you know how to import their part into LTspice? My only
experience with spice is with using the built in library components -
I've never had to work with the actual text files themselves

-Michael


Hello Michael,

Inside this zip-file is a model file laser_diode.lib .
It contains a line .model dlaser D(...)
Nothing great (Is=5e-37 N=1 ....). I doubt it's realistic,
but it doesn't matter for your application. Just use it as it is.

Best regards,
Helmut

 

[Jim Thompson]

Does not having a Spice model stop the project dead? I wonder how TVs
and Radar were invented.

John

25 of my 48 "professional" years designing circuits was BS... Before
Simulators ;-)

I had ZERO design failure rate with breadboards... around 1% with
simulators... although I must admit the simulated designs were FAR
more complex than the breadboarded designs.

...Jim Thompson

 

[Joerg]

25 of my 48 "professional" years designing circuits was BS... Before
Simulators ;-)

Mine are still continuing because there are things that Spice don't
catch. Then there are things that only Spice can catch (but not that
frequently).

I had ZERO design failure rate with breadboards... around 1% with
simulators... although I must admit the simulated designs were FAR
more complex than the breadboarded designs.

Now how was that with the switcher design of yours where you were 100%
sure it would be bullet-proof? The one where El Capitan came in and
rocked the power switch a few times, followed by a loud bang and molten
solder flying about?

 

[Joerg]

Hi there - I was thinking about trying to design a laser driver over
the weekend. Unfortunately, I can't seem to find a spice model for a
laser diode, putting a bit of a squabash on that plan.

Anybody know where I can find one? Ideally I'd find one for a very
normal ~5mw red laser diode - like those you'd find in a cheap laser
pointer.

As others have said just build it. That's what I did for a client,
didn't touch Spice during that project except for verifying one RF bandpass.

But watch out not to point the laser diode into eyes or other sensitive
areas. Mind your pets, too. I've got a nosy Shepard checking out my
stuff once in a while and she doesn't know that IR can be dangerous as
well.

 

[Jim Thompson]

Mine are still continuing because there are things that Spice don't
catch. Then there are things that only Spice can catch (but not that
frequently).



Now how was that with the switcher design of yours where you were 100%
sure it would be bullet-proof? The one where El Capitan came in and
rocked the power switch a few times, followed by a loud bang and molten
solder flying about?

That was a breadboard ;-)

BTW, it wasn't El Capitan, it was the digital guru prick at GenRad ;-)

...Jim Thompson

 

[Hammy]

Hi - Do you know how to import their part into LTspice? My only
experience with spice is with using the built in library components -
I've never had to work with the actual text files themselves

-Michael

Hi Michael

I don't use LTSPICE. They do have a user group here

http://tech.groups.yahoo.com/group/LTspice/

Someone there may have some pointers for you, or try
sci.electronics.cad.

 

[Hammy]

Any good reason that I have to have Flash installed to download this?

None that I know of its right from Cadence,there appnotes section.

 

[Vladimir Vassilevsky]

Jim Thompson wrote:

25 of my 48 "professional" years designing circuits was BS... Before
Simulators ;-)

I had ZERO design failure rate with breadboards... around 1% with
simulators...

I bet if you hadn't those 25 years with breadboards then the simulator
failure rate would be a lot higher. The simulation can be only as good
as the person's knowledge about the reality, plus the knowledge of the
limits of the simulation.

although I must admit the simulated designs were FAR
more complex than the breadboarded designs.

Wiener (?) said that the computer is the amplifier for the brains, but
not the replacement.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

 

[Vladimir Vassilevsky]

Hi there - I was thinking about trying to design a laser driver over
the weekend. Unfortunately, I can't seem to find a spice model for a
laser diode, putting a bit of a squabash on that plan.

There is a whole bunch of the different laser modulator ICs. Unless you
are after some extraordinary parameters, there is no point to design the
diode driver of your own.

Anybody know where I can find one? Ideally I'd find one for a very
normal ~5mw red laser diode - like those you'd find in a cheap laser
pointer.

Take a spice model of a diode and make it parameters to match the
datasheet on the laser. BTW, "very normal" red laser diodes can actually
belong to one of the two completely different types.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com