Can a laser diode like the VCSEL OPV382 850nm be pulsed similar to an
IRDA; carrier frequency and data?

Data sheet.

http://www.optekinc.com/pdf/OPV382.pdf

What would be the maximum transmission distance?

The 2 page data sheet on the diode is pathetic, so if anyone has
experience with these. Such  as thermal derating.Maximum peak current
etc.

The closest detector I can find is the TSOP7000 Peak spectral
sensitivity of 870nm, could this be used with this LD? 

Data sheet.

http://info.hobbyengineering.com/specs/Vishay-TSOP7000.pdf

I've never considered using them because of the price, but these LD's
are only $6.

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Hammy wrote:
> Can a laser diode like the VCSEL OPV382 850nm be pulsed similar to an
> IRDA; carrier frequency and data?
> 
> Data sheet.
> 
> http://www.optekinc.com/pdf/OPV382.pdf
> 
> What would be the maximum transmission distance?
> 
> The 2 page data sheet on the diode is pathetic, so if anyone has
> experience with these. Such  as thermal derating.Maximum peak current
> etc.
> 
> The closest detector I can find is the TSOP7000 Peak spectral
> sensitivity of 870nm, could this be used with this LD? 
> 
> Data sheet.
> 
> http://info.hobbyengineering.com/specs/Vishay-TSOP7000.pdf
> 
> I've never considered using them because of the price, but these LD's
> are only $6.

Yes, probably. The cheapo laser pen diodes have been used to send sound
to a photodiode, so these shouldn't have much trouble.

- --
Brendan Gillatt | GPG Key: 0xBF6A0D94
brendan {a} brendangillatt (dot) co (dot) uk
http://www.brendangillatt.co.uk
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On Jun 4, 3:52 am, Hammy <spa...@hotmail.com> wrote:
> Can a laser diode like the VCSEL OPV382 850nm be pulsed similar to an
> IRDA; carrier frequency and data?

VCSELs seem to have an upper limit on the frequency they are modulated
somewhere above 20GHz.  If you are modulating it below that frequency,
you won't be limited by any funamental limit of the VCSEL technology.

The leadframe may work as a low pass filter leading to the actual
VCSEL device.  If you keep the legs short, you shouldn't have too much
trouble modulating it.


>
> Data sheet.
>
> http://www.optekinc.com/pdf/OPV382.pdf
>
> What would be the maximum transmission distance?
>
> The 2 page data sheet on the diode is pathetic, so if anyone has
> experience with these. Such  as thermal derating.Maximum peak current
> etc.
>
> The closest detector I can find is the TSOP7000 Peak spectral
> sensitivity of 870nm, could this be used with this LD?
>
> Data sheet.
>
> http://info.hobbyengineering.com/specs/Vishay-TSOP7000.pdf
>
> I've never considered using them because of the price, but these LD's
> are only $6.

On Wed, 04 Jun 2008 10:52:29 GMT, Hammy <s...@hotmail.com> wrote:

>Can a laser diode like the VCSEL OPV382 850nm be pulsed similar to an
>IRDA; carrier frequency and data?
>
>Data sheet.
>
>http://www.optekinc.com/pdf/OPV382.pdf


I've had terrible experiences with the Optek parts. I think they buy
their lasers from random guys in overcoats in the back alleys of
Taiwan. They keep changing, and they don't seem to know much about
them. The last batch we bought had a really bizarre time-domain
response, as if a very slow-recovery PIN diode were in series with the
laser.

But in general a small cheap 850 laser will deliver a milliwatt or two
of power at maybe 10-20 mA and is easily modulated up to a GHz at
least.


>
>What would be the maximum transmission distance?

Depends on the optics. 

>
>The 2 page data sheet on the diode is pathetic, so if anyone has
>experience with these. Such  as thermal derating.Maximum peak current
>etc.
>
>The closest detector I can find is the TSOP7000 Peak spectral
>sensitivity of 870nm, could this be used with this LD?

The Optek silicon PIN receiver parts are OK.

John

On Wed, 4 Jun 2008 06:32:05 -0700 (PDT), MooseFET <k...@rahul.net>
wrote:

>On Jun 4, 3:52 am, Hammy <spa...@hotmail.com> wrote:
>> Can a laser diode like the VCSEL OPV382 850nm be pulsed similar to an
>> IRDA; carrier frequency and data?
>
>VCSELs seem to have an upper limit on the frequency they are modulated
>somewhere above 20GHz.  If you are modulating it below that frequency,
>you won't be limited by any funamental limit of the VCSEL technology.
>
>The leadframe may work as a low pass filter leading to the actual
>VCSEL device.  If you keep the legs short, you shouldn't have too much
>trouble modulating it.
>
>
>>
>> Data sheet.
>>
>> http://www.optekinc.com/pdf/OPV382.pdf
>>
>> What would be the maximum transmission distance?
>>
>> The 2 page data sheet on the diode is pathetic, so if anyone has
>> experience with these. Such  as thermal derating.Maximum peak current
>> etc.
>>
>> The closest detector I can find is the TSOP7000 Peak spectral
>> sensitivity of 870nm, could this be used with this LD?
>>
>> Data sheet.
>>
>> http://info.hobbyengineering.com/specs/Vishay-TSOP7000.pdf
>>
>> I've never considered using them because of the price, but these LD's
>> are only $6.

Could these be used effectively for free air transmission?

I'll explain my application. I built a security system which includes
a dual beam IR barrier. I'm using a dual beam with a 25ms delay,i.e if
both beams are obstructed simultaneously for 25ms trip the alarm. I'm
currently using tsal6100 emitters, and spectral matching detector from
Panasonic. I can easily obtain the range (70ft) I need with this
setup. The problem is I have to separate the emitters and detectors by
a couple of feet  (vertically) or one emitter will flood both
detectors. I know the solution is using a collimation system with
optics, these aren't readily available though. There are some budget
optics on the internet but they lack datasheets.

If these LD's can be used for this application I could fit everything
in one enclosure, with 5 or 6 inches of vertical separation.

Before I order a couple I thought I'd ask and see if anyone has any
experience with them, and could tell me if it's practical to sub out
the TSAL6100 with the LD's? With a closely matched detector the
TSOP7000.

Thanks

Hammy wrote:
> Can a laser diode like the VCSEL OPV382 850nm be pulsed similar to an
> IRDA; carrier frequency and data?
> 
> Data sheet.
> 
> http://www.optekinc.com/pdf/OPV382.pdf
> 
> What would be the maximum transmission distance?
> 
> The 2 page data sheet on the diode is pathetic, so if anyone has
> experience with these. Such  as thermal derating.Maximum peak current
> etc.
> 
> The closest detector I can find is the TSOP7000 Peak spectral
> sensitivity of 870nm, could this be used with this LD? 
> 
> Data sheet.
> 
> http://info.hobbyengineering.com/specs/Vishay-TSOP7000.pdf
> 
> I've never considered using them because of the price, but these LD's
> are only $6.

Garden-variety cleaved-cavity diode lasers can be modulated up to ~1 
GHz, and VCSELs are generally faster than that.  The packaging on this 
one doesn't look too promising for multi-GHz modulation, but for IRDA 
you should definitely be in the clear.

Cheers,

Phil Hobbs

On Jun 4, 8:10 am, Hammy <spa...@hotmail.com> wrote:
> On Wed, 4 Jun 2008 06:32:05 -0700 (PDT), MooseFET <kensm...@rahul.net>
> wrote:
>
>
>
> >On Jun 4, 3:52 am, Hammy <spa...@hotmail.com> wrote:
> >> Can a laser diode like the VCSEL OPV382 850nm be pulsed similar to an
> >> IRDA; carrier frequency and data?
>
> >VCSELs seem to have an upper limit on the frequency they are modulated
> >somewhere above 20GHz.  If you are modulating it below that frequency,
> >you won't be limited by any funamental limit of the VCSEL technology.
>
> >The leadframe may work as a low pass filter leading to the actual
> >VCSEL device.  If you keep the legs short, you shouldn't have too much
> >trouble modulating it.
>
> >> Data sheet.
>
> >>http://www.optekinc.com/pdf/OPV382.pdf
>
> >> What would be the maximum transmission distance?
>
> >> The 2 page data sheet on the diode is pathetic, so if anyone has
> >> experience with these. Such  as thermal derating.Maximum peak current
> >> etc.
>
> >> The closest detector I can find is the TSOP7000 Peak spectral
> >> sensitivity of 870nm, could this be used with this LD?
>
> >> Data sheet.
>
> >>http://info.hobbyengineering.com/specs/Vishay-TSOP7000.pdf
>
> >> I've never considered using them because of the price, but these LD's
> >> are only $6.
>
> Could these be used effectively for free air transmission?
>
> I'll explain my application. I built a security system which includes
> a dual beam IR barrier. I'm using a dual beam with a 25ms delay,i.e if
> both beams are obstructed simultaneously for 25ms trip the alarm. I'm
> currently using tsal6100 emitters, and spectral matching detector from
> Panasonic. I can easily obtain the range (70ft) I need with this
> setup. The problem is I have to separate the emitters and detectors by
> a couple of feet  (vertically) or one emitter will flood both
> detectors. I know the solution is using a collimation system with
> optics, these aren't readily available though. There are some budget
> optics on the internet but they lack datasheets.
>
> If these LD's can be used for this application I could fit everything
> in one enclosure, with 5 or 6 inches of vertical separation.
>
> Before I order a couple I thought I'd ask and see if anyone has any
> experience with them, and could tell me if it's practical to sub out
> the TSAL6100 with the LD's? With a closely matched detector the
> TSOP7000.


There is no reason you can't pulse the Lasers at, lets say, 10KHz with
a 25% duty cycle.  Since they are diven by the same electronics, it is
easy to make them alternate.  The detection circuit can be fairly
simple.

At the photo detector, a 10Khz band pass filter will have a large
output if one Laser is blocked.  A 20KHz filter will have at least a
fairly large output unless both are blocked.

If you need to know which Laser is blocked, you need to make the pulse
pattern different or bring the information about which is on from the
transmitter to the receiver.  Alternating one pulse on Laser #1 and
then two on Laser #2 would be a simple way to do the different
patterns.

Why not use on emitter and one receiver on each side of the gap.  Then
each
will only look into one emitter.


On Jun 4, 8:10 am, Hammy <spa...@hotmail.com> wrote:
> I'll explain my application. I built a security system which includes
> a dual beam IR barrier. I'm using a dual beam with a 25ms delay,i.e if
> both beams are obstructed simultaneously for 25ms trip the alarm. I'm
> currently using tsal6100 emitters, and spectral matching detector from
> Panasonic. I can easily obtain the range (70ft) I need with this
> setup. The problem is I have to separate the emitters and detectors by
> a couple of feet  (vertically) or one emitter will flood both
> detectors.