On Monday 01 April 2013, Attila Kinali wrote:
> On Mon, 1 Apr 2013 14:24:58 +0100
>
> Wolfgang wrote:
> > Anyway, each of these down-mixing approaches needs to resolve the
> > mirror frequency problem. I.e. if you modulate your receiver with
> > 7.1 GHz (or use an EOM to do that optically) and det
Reverse biased diodes are not very low impedance. You can't really drive
a low impedance with them.
In fact, the high impedance of the photodiode leads to all sorts of
ugliness in noise analysis. This is well documented in Graeme's book. I
think TI also has an app note on feedback networks for
I think that you should be able to take the signal right out of the
backbiased diode and run it straight into a microwave mixer w/ a fixed 7
GHz LO and frequency discrimitate the IF output from the mixer to generate
a control signal for your LASER.
In theory, if your LASERS were very, very, very g
On Mon, 1 Apr 2013 14:24:58 +0100
Wolfgang wrote:
> On Monday 01 April 2013, Attila Kinali wrote:
> >> [APD...]
> >
> > I think the gain modulated approach to downconvert the signal should work.
> >
> Anyway, each of these down-mixing approaches needs to resolve the
> mirror frequency problem.
On Mon, 1 Apr 2013 14:28:49 +0100
Wolfgang wrote:
> On Saturday 30 March 2013, Attila Kinali wrote:
> > So far, i figured out that PIN photodiodes can go up to several 100MHz
> > transition frequency and avalanche photodiodes are available up to 2GHz.
> > The only photodiodes that go higher are t
frequency measurement
Reply-To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Photodiodes for high frequency OPLL
On Sun, 31 Mar 2013 20:31:58 -0700
gary wrote:
> On 3/31/2013 5:52 AM, Attila Kinali wrote:
> >
> > Probably. But as steep filte
On Monday 01 April 2013, Bruce Griffiths wrote:
> Back to the original problem:
>
> An AOM could be used to generate a sideband 7GHz above (or below) the
> output of 1 laser which could then be mixed with the output of the other
> laser using a narrow bandwidth photodiode.
>
That's going to get tou
On Saturday 30 March 2013, Attila Kinali wrote:
> So far, i figured out that PIN photodiodes can go up to several 100MHz
> transition frequency and avalanche photodiodes are available up to 2GHz.
> The only photodiodes that go higher are those for the telecom range
> at 1-1.5um, which is a bit low
On 30 March 2013 11:48, Attila Kinali wrote:
> So far, i figured out that PIN photodiodes can go up to several 100MHz
> transition frequency and avalanche photodiodes are available up to 2GHz.
It might be worth Picosecond Pulsed Labs to. I can't see it on their
web site, but I would not be surpr
Attila Kinali wrote:
On Mon, 01 Apr 2013 22:32:11 +1300
Bruce Griffiths wrote:
Attila Kinali wrote:
On Mon, 01 Apr 2013 09:08:51 +1300
Bruce Griffiths wrote:
Nothing to do with laser line width.
Merely indicating that the photodiode mixer can be used with a suitable
LO
On Mon, 01 Apr 2013 22:32:11 +1300
Bruce Griffiths wrote:
> Attila Kinali wrote:
> > On Mon, 01 Apr 2013 09:08:51 +1300
> > Bruce Griffiths wrote:
> >
> >
> >> Nothing to do with laser line width.
> >> Merely indicating that the photodiode mixer can be used with a suitable
> >> LO to build a
Attila Kinali wrote:
On Mon, 01 Apr 2013 09:08:51 +1300
Bruce Griffiths wrote:
Nothing to do with laser line width.
Merely indicating that the photodiode mixer can be used with a suitable
LO to build an optical spectrum analyser front end.
Are you refering to heterodyne spectrum ana
On Mon, 01 Apr 2013 09:08:51 +1300
Bruce Griffiths wrote:
> Nothing to do with laser line width.
> Merely indicating that the photodiode mixer can be used with a suitable
> LO to build an optical spectrum analyser front end.
Are you refering to heterodyne spectrum analyser?
On Sun, 31 Mar 2013 10:47:29 -0400
Mike S wrote:
> On 3/30/2013 7:48 AM, Attila Kinali wrote:
> > So far, i figured out that PIN photodiodes can go up to several 100MHz
> > transition frequency and avalanche photodiodes are available up to 2GHz.
> > The only photodiodes that go higher are those f
On Sun, 31 Mar 2013 20:31:58 -0700
gary wrote:
> On 3/31/2013 5:52 AM, Attila Kinali wrote:
> >
> > Probably. But as steep filters for optics are kind of hard to come by,
> > i think a super heterodyne design isn't realy going to work.
> I've bought optical filters from Andover. They are pretty
On Sun, 31 Mar 2013 15:27:02 +0100
David Kirkby wrote:
> You can't modulate the sensitivity of a PIN diode by an adjustable
> bias like you can in an APD. For a PIN diode, at the wavelengths you
> are talking of, you basically get around 0.5 Amps/Watt from the diode.
Right.. Forgot about that ^^
I've bought optical filters from Andover. They are pretty cheap, at
least compared to the rest of the industry.
http://www.andovercorp.com/Web_store/index.php
On 3/31/2013 5:52 AM, Attila Kinali wrote:
Probably. But as steep filters for optics are kind of hard to come by,
i think a super het
Noise adds in a RMS fashion unless it is correlated. So a differential
amplifier can cancel common mode noise, but that is about it. The diode,
being a single ended device, seems to me to be impossible to bias in a
manner where the noise from the bias circuitry will cancel out.
Note it may not
Nothing to do with laser line width.
Merely indicating that the photodiode mixer can be used with a suitable
LO to build an optical spectrum analyser front end.
Bruce
Attila Kinali wrote:
Moin,
On Sun, 31 Mar 2013 12:28:59 +1300
Bruce Griffiths wrote:
With a suitable low noise tunable
On 3/30/2013 7:48 AM, Attila Kinali wrote:
So far, i figured out that PIN photodiodes can go up to several 100MHz
transition frequency and avalanche photodiodes are available up to 2GHz.
The only photodiodes that go higher are those for the telecom range
at 1-1.5um, which is a bit low for my need
On 31 March 2013 13:52, Attila Kinali wrote:
>
> But probably using an APD with gain modulation at 1GHz or so, i could
> down modulate the signal to something that is easier to handle
> (ie something similar as a direct conversion software defined radios).
>
> I wonder if this would work with norm
On Sat, 30 Mar 2013 20:45:43 +
David Kirkby wrote:
> Fulll thesis here
> http://www.medphys.ucl.ac.uk/research/borl/docs/dkirkby.pdf
>
> I have seen systems where one sinusoidally modulates the voltage of a
> photomultipler tube. You could do the same with an APD. Then it acts a
> a mixer. Es
Moin,
On Sun, 31 Mar 2013 12:28:59 +1300
Bruce Griffiths wrote:
> With a suitable low noise tunable LO (laser) the frequency spectrum
> beyond the photodiode electrical bandwidth can be explored.
I don't exactly get how the laser spectrum (line width?) can be
exploited to go beyond the photodi
On Sat, 30 Mar 2013 21:40:47 +
li...@lazygranch.com wrote:
> The circuit is something like the instrumentation amplifier.
> The description starts on page 207 with a schematic on page 208.
> I can scan it later, but the circuit is easy to describe. Think of two
> op amps in the classic current
Reply-To: Discussion of precise time and frequency measurement
>
> Subject: Re: [time-nuts] Photodiodes for high frequency OPLL
>
> The detectors don't have to be fast enough to keep up with optical
> carrier frequency as long as the incident optical power has a component
&
On 30 March 2013 19:50, Attila Kinali wrote:
> On Sat, 30 Mar 2013 18:43:03 +
> David Kirkby wrote:
>
>> I would contact Hammamatsu Photonics
>>
>> http://www.hamamatsu.com
> This might be a good idea. Thanks!
>> I played tricks during my Ph.D. of gain-modulating an APD with a step
>> recov
measurement
Subject: Re: [time-nuts] Photodiodes for high frequency OPLL
The detectors don't have to be fast enough to keep up with optical
carrier frequency as long as the incident optical power has a component
at a much lower frequency.
Bruce
ed breya wrote:
Ooops - never mind. I
time and frequency measurement
Subject: Re: [time-nuts] Photodiodes for high frequency OPLL
The detectors don't have to be fast enough to keep up with optical
carrier frequency as long as the incident optical power has a component
at a much lower frequency.
Bruce
ed breya
The detectors don't have to be fast enough to keep up with optical
carrier frequency as long as the incident optical power has a component
at a much lower frequency.
Bruce
ed breya wrote:
Ooops - never mind. I wrote before my memory was updated. My
experience in E-O stuff was years ago using
The circuit I've seen is:
|--||---
+Vb---o--|<> amp
|--||-o-
Vb gnd--|
The diode is reverse biased by 50 to several hundred volts.
The two caps are DC bypass caps w/ very short leads.
The output is a
Ooops - never mind. I wrote before my memory was updated. My
experience in E-O stuff was years ago using AM at relatively low
frequency, and nowhere near the lasers and microwave/gigabit/sec
stuff - I didn't think the detectors were fast enough to actually
keep up with the optical carrier frequ
cs.)
--Original Message--
From: Attila Kinali
To: li...@lazygranch.com
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Photodiodes for high frequency OPLL
Sent: Mar 30, 2013 12:03 PM
On Sat, 30 Mar 2013 17:29:45 +
li...@lazygranch.com wrote:
> You los
A photodiode is in fact a nonlinear device for optical fields as it is
essentially a linear optical power detector.
The output is proportional to the incident optical power not the field
amplitude.
Photomixers are routinely used in wide range of diverse application such
as translating the freque
On Sat, 30 Mar 2013 12:45:52 -0700 (PDT)
Robert LaJeunesse wrote:
> Maybe I'm jaded a bit, but in this town the sub-10GHz optical stuff is
> considered kinda slow. The guys down the street, Picometrix, have been doing
> 40+GHz optical receivers for over 15 years. They claim "1.5G to 100G and fr
On Sat, 30 Mar 2013 18:43:03 +
David Kirkby wrote:
> I would contact Hammamatsu Photonics
>
> http://www.hamamatsu.com
>
> and see if they can help. They might havae something in development,
> that is not on the web site. If you are in a uni, they might be
> especially helpful - they paid
Maybe I'm jaded a bit, but in this town the sub-10GHz optical stuff is
considered kinda slow. The guys down the street, Picometrix, have been doing
40+GHz optical receivers for over 15 years. They claim "1.5G to 100G and from
400nm to 1650nm" so probably they can help. http://www.picometrix.com/
On Sat, 30 Mar 2013 10:52:54 -0700 (PDT)
"J. Forster" wrote:
> My understanding is that you want to operate photodiodes with high reverse
> bias for the best frequency response. The bias widens the space charge
> layer, thereby reducing the capacitance of the device. The high electric
> fields in
On 30 March 2013 11:48, Attila Kinali wrote:
> Moin,
>
> I'm currently reading up some stuff on optical PLLs and am stuck with some
> details i cannot find any data on.
>
> The goal is to make two lasers locked with about 7GHz of offset to eachother.
>
> So far, i figured out that PIN photodiodes
On Sat, 30 Mar 2013 13:46:51 -0400
"jmfranke" wrote:
> I used UDT PIN10 photodiodes to observe the mode spacings in HeNe lasers.
> The typical mode spacings were around 600 MHz.
This sounds interesting. According to the datasheet i've found,
the PIN10D has a response time of 25ns, which would s
On Sat, 30 Mar 2013 17:29:45 +
li...@lazygranch.com wrote:
> You lose me at damping per decade? Is damping the right word?
> Do you mean high frequency rolloff?
Er.. yes. Frequency rolloff... Sorry, my native language got the better of me.
> Most texts on photodiodes go into bootstrapping t
On Fri, 29 Mar 2013 17:20:35 -0700
ed breya wrote:
> I don't think that you can effectively directly mix two laser
> wavelengths in a semiconductor light detector and get a useable IF -
> it's hard enough just to get the tens of GHz modulation signals out
> above the noise floor, let alone a t
On Sat, 30 Mar 2013 10:00:08 -0800
David McQuate wrote:
> You'll need a photodiode that can detect photons at your lasers'
> wavelength.
Yes, of course.
> You may be able to use a photodiode at a shorter than its
> design wavelength as long as there are not coatings (eg anti-reflection)
>
Moin Peter,
On Sat, 30 Mar 2013 09:47:26 -0700
Peter Monta wrote:
> > The goal is to make two lasers locked with about 7GHz of offset to
> > eachother.
> >
> > So far, i figured out that PIN photodiodes can go up to several 100MHz
> > transition frequency and avalanche photodiodes are available
ster"
To: ; "Discussion of precise time and frequency
measurement"
Sent: Saturday, March 30, 2013 1:52 PM
Subject: Re: [time-nuts] Photodiodes for high frequency OPLL
My understanding is that you want to operate photodiodes with high reverse
bias for the best frequency response. T
8:20 PM
To:
Subject: Re: [time-nuts] Photodiodes for high frequency OPLL
> I don't think that you can effectively directly mix two laser wavelengths
> in a semiconductor light detector and get a useable IF - it's hard enough
> just to get the tens of GHz modulation signals ou
iginal Message-
> From: Attila Kinali
> Sender: time-nuts-boun...@febo.com
> Date: Sat, 30 Mar 2013 12:48:01
> To:
> Reply-To: Discussion of precise time and frequency measurement
>
> Subject: [time-nuts] Photodiodes for high frequency OPLL
>
> Moin,
>
>
I used UDT PIN10 photodiodes to observe the mode spacings in HeNe lasers.
The typical mode spacings were around 600 MHz.
John WA4WDL
--
From: "ed breya"
Sent: Friday, March 29, 2013 8:20 PM
To:
Subject: Re: [time-nuts] Photodiode
depend on gain
bandwidth product to do the same.
-Original Message-
From: Attila Kinali
Sender: time-nuts-boun...@febo.com
Date: Sat, 30 Mar 2013 12:48:01
To:
Reply-To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Photodiodes for high frequency O
I don't think that you can effectively directly mix two laser
wavelengths in a semiconductor light detector and get a useable IF -
it's hard enough just to get the tens of GHz modulation signals out
above the noise floor, let alone a tiny difference signal between
hundreds of THz. You need an o
You'll need a photodiode that can detect photons at your lasers'
wavelength. You may be able to use a photodiode at a shorter than its
design wavelength as long as there are not coatings (eg anti-reflection)
that block the wavelength of interest. You'll need to make sure that
both lasers illu
Hi Attila,
> The goal is to make two lasers locked with about 7GHz of offset to
> eachother.
>
> So far, i figured out that PIN photodiodes can go up to several 100MHz
> transition frequency and avalanche photodiodes are available up to 2GHz.
>
If you need photodiode response only near 7 GHz, as
Moin,
I'm currently reading up some stuff on optical PLLs and am stuck with some
details i cannot find any data on.
The goal is to make two lasers locked with about 7GHz of offset to eachother.
So far, i figured out that PIN photodiodes can go up to several 100MHz
transition frequency and avalan
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