[Laser] Spice model for photodiode?

Thu, 26 Feb 2004 10:28:39 EST

Hello Art

I can't give you a complete answer for your request
but in my Fiber Optics days, we used a simplified
model for PIN diodes consisting of an ideal current source with
a parasitic parallel capacitance and shunt resistance.
It seemed to be adequate as a first approximation
for designs at  OC-1 ( 52 Mb/s) up to OC-48 ( 2.5 Gb/s)
You can get a reasonable set of parameters by making fairly 
simple measurements with the diode that you intend to use--
A light source with known power output and coupling efficiency
will be very helpful in making the measurements--- Let
me dig through my archives ( now in storage ) to see
what I can find and I'll pass them along to you as soon
as I can find them.. ( There are many boxes to dig through )

Another item of interest might be an article that my
former boss, Brian Wheeler, wrote in the early 90s--It
was called  " The Spice of Light " and was published
in either Lightwave or Electronic Design--I will see if I
can locate this article  and I'll pass it along as well......

Good luck in your simulations--Free space optics are much
tougher than pushing light down optical fibers !!!!!!!!

Ray Johnson  KE3QY
Applications Engineer, ( now retired ) 
BT&D / HP Fiber Optics Components Group ( 1988-1996)
Lucent Optoelectronics ( 1996-1998 )

++++++++++++++++++++++++++++++++==================

In a message dated 04-02-25 08:11:27 EST, you write:

<< Subj:     [Laser] Spice model for photodiode?
 Date:  04-02-25 08:11:27 EST
 From:  [email protected] (Art)
 Sender:    [email protected]
 Reply-to:  [email protected]
 To:    [email protected]

 Good day all,

 I'm a new spice user and for my first project, I wanted to model the K3PGP 
 photodiode preamp, especially the daylight version. I'm interested in this 
 because it appears that the majority of the sensitivity goes away due to 
 the dark version components effectively shunting the photodiode.

 Burr-Brown has an ap note on daylight use of their opt210 integrated 
 photodiode/amp chips. They use a very large series resistor and the full 
 vcc to feed small currents into the op amp, which correct for the daylight 
 ambient light. After the output of the photodiode amp goes to zero in the 
 presence of ambient light, it is maintained there by another op amp that 
 monitors the output voltage and attempts to hold it there-except it has a 
 longer time constant (narrower bandwidth) than the desired reception 
 frequency-so it is always nudging the output in the right direction, but 
 never quite 'catches up'. In effect, the daylight cancelling electronics is 
 variable and constantly correcting. Burr-Brown says the sensitivity lost is 
 'minimal'.

 I think the ability to make daylight QSO's without a severe loss in 
 sensitivity would be a good thing!

 Does anyone have a spice model for a photodiode or know where I can get one?

 Thanks,

 Art

 _______________________________________________
 Laser mailing list
 [email protected]
 http://mailman.qth.net/mailman/listinfo/laser

 ----------------------- Headers --------------------------------
 Return-Path: <[email protected]>
 Received: from  rly-yg06.mx.aol.com (rly-yg06.mail.aol.com [172.18.180.102]) 
by air-yg03.mail.aol.com (v98.6) with ESMTP id MAILINYG34-783403c9ede25e; 
Wed, 25 Feb 2004 08:11:26 -0500
 Received: from  mailman.qth.net (mailman.qth.net [63.238.179.60]) by 
rly-yg06.mx.aol.com (v98.5) with ESMTP id MAILRELAYINYG61-783403c9ede25e; Wed, 25 Feb 
2004 08:10:54 -0500
 Received: from mailman.qth.net (mailman.qth.net [63.238.179.60])
    by mailman.qth.net (Postfix) with ESMTP
    id 9B04C328B0F; Wed, 25 Feb 2004 08:12:02 -0500 (EST)
 Delivered-To: [email protected]
 Received: from warpspeed.megalink.net (warpspeed.megalink.net [205.243.60.4])
    by mailman.qth.net (Postfix) with ESMTP id 2E99D3286FC
    for <[email protected]>; Wed, 25 Feb 2004 08:11:24 -0500 (EST)
 Received: from [63.164.26.199] (HELO ab.uninets.net)
   by warpspeed.megalink.net (CommuniGate Pro SMTP 4.1.1)
   with ESMTP id 159184459 for [email protected]; Wed, 25 Feb 2004 
08:09:04 -0500
 Message-Id: <[email protected]>
 X-Sender: [email protected]
 X-Mailer: QUALCOMM Windows Eudora Version 6.0.0.22
 To: [email protected]
 From: Art <[email protected]>
 In-Reply-To: <[email protected]
  link.net>
 References: 
<7964756.1077641691245.JavaMail.root@thecount.psp.pas.earthlink.net>
 Mime-Version: 1.0
 Content-Type: text/plain; charset="us-ascii"; format=flowed
 Subject: [Laser] Spice model for photodiode?
 Sender: [email protected]
 Errors-To: [email protected]
 X-BeenThere: [email protected]
 X-Mailman-Version: 2.0.8
 Precedence: list
 Reply-To: [email protected]
 List-Id: <.font color=red><.B>== Free Space LASER Communications 
==<./font><./B> <laser.mailman.qth.net>
 List-Archive: <http://mailman.qth.net/pipermail/laser/>
 Date: Wed, 25 Feb 2004 08:07:23 -0500
 X-AOL-IP: 63.238.179.60
 X-AOL-SCOLL-SCORE: 0:XXX:XX
 X-AOL-SCOLL-URL_COUNT: 0

  >>