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| Hazem... |
 Posted: Tue Oct 06, 2009 5:52 am |
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Guest
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Please excuse me if this question has been asnwered before. The search
function does not work for older posts on Google Groups anymore.
I am trying to decide whether to acquire a VCSEL or a DFB laser for a
measurement application. The laser will be coupled to a single-mode
fiber, so many of the advantages of VCSEL over DFB diode lasers become
irrelevant. The one criterion I care most about is frequency/
wavelength stability. My understanding is that modern DFB or VCSELs
both have very good stability, but I'd like to know which one is the
best. Wavelength will be in the red/ near IR regions, and I have not
chosen it yet. Again, stability is more important and the choice of
wavelength will be secondary, as long as it is in the long visible or
short IR regions.
Your help is much appreciated.
Hazem |
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| Hazem... |
| Posted: Tue Oct 06, 2009 8:43 am |
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Guest
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On Oct 6, 12:58 pm, Phil Hobbs
<pcdhSpamMeSensel... at (no spam) electrooptical.net> wrote:
[quote:813e208c07]Hazem wrote:
Please excuse me if this question has been asnwered before. The search
function does not work for older posts on Google Groups anymore.
I am trying to decide whether to acquire a VCSEL or a DFB laser for a
measurement application. The laser will be coupled to a single-mode
fiber, so many of the advantages of VCSEL over DFB diode lasers become
irrelevant. The one criterion I care most about is frequency/
wavelength stability. My understanding is that modern DFB or VCSELs
both have very good stability, but I'd like to know which one is the
best. Wavelength will be in the red/ near IR regions, and I have not
chosen it yet. Again, stability is more important and the choice of
wavelength will be secondary, as long as it is in the long visible or
short IR regions.
Your help is much appreciated.
Hazem
What sort of stability do you need? Barefoot diodes can be 'good' or
'horrible', depending on what your definition of 'good' is.
Cheers
[/quote:813e208c07]
Basically, best available. I read an article somewhere that claimed
+/-0.001nm/degC. I am trying to see if I can get a laser that is
stable enough to make the type of measurement that I need done
feasible. So far, all the lasers I have tested were not stable enough.
Sorry I can't explain what type of measurement I am trying to perform.
I am bound by a non-disclosure agreement. Hopefully after the project
is concluded a paper will be published with all the details.
Thank you,
Hazem
[quote:813e208c07]
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot nethttp://electrooptical.net- Hide quoted text -
- Show quoted text -[/quote:813e208c07] |
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| Hazem... |
| Posted: Tue Oct 06, 2009 9:05 am |
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Guest
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On Oct 6, 2:43 pm, Hazem <hazem.biqa... at (no spam) gmail.com> wrote:
[quote:b3272f2963]On Oct 6, 12:58 pm, Phil Hobbs
pcdhSpamMeSensel... at (no spam) electrooptical.net> wrote:
Hazem wrote:
Please excuse me if this question has been asnwered before. The search
function does not work for older posts on Google Groups anymore.
I am trying to decide whether to acquire a VCSEL or a DFB laser for a
measurement application. The laser will be coupled to a single-mode
fiber, so many of the advantages of VCSEL over DFB diode lasers become
irrelevant. The one criterion I care most about is frequency/
wavelength stability. My understanding is that modern DFB or VCSELs
both have very good stability, but I'd like to know which one is the
best. Wavelength will be in the red/ near IR regions, and I have not
chosen it yet. Again, stability is more important and the choice of
wavelength will be secondary, as long as it is in the long visible or
short IR regions.
Your help is much appreciated.
Hazem
What sort of stability do you need? Barefoot diodes can be 'good' or
'horrible', depending on what your definition of 'good' is.
Cheers
Basically, best available. I read an article somewhere that claimed
+/-0.001nm/degC. I am trying to see if I can get a laser that is
stable enough to make the type of measurement that I need done
feasible. So far, all the lasers I have tested were not stable enough.
Sorry I can't explain what type of measurement I am trying to perform.
I am bound by a non-disclosure agreement. Hopefully after the project
is concluded a paper will be published with all the details.
Thank you,
Hazem
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot nethttp://electrooptical.net-Hide quoted text -
- Show quoted text -- Hide quoted text -
- Show quoted text -- Hide quoted text -
- Show quoted text -
[/quote:b3272f2963]
Correction 0.001nm/degC, not +/-0.001nm/degC.
I do not know beforehand the minimum frequency stability i require,
because the lasers I have had the chance to test did not list it, and
there are other factors that exacerbated the effect of frequency
instability on measurement. I do not want, however, to place an upper
limit. i.e., the more stable, the better for my application. Money is
not an issue.
Regards |
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| Hazem... |
| Posted: Tue Oct 06, 2009 9:16 am |
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Guest
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On Oct 6, 3:09 pm, Phil Hobbs <pcdhSpamMeSensel... at (no spam) electrooptical.net>
wrote:
[quote:4c2b8a46b1]Hazem wrote:
On Oct 6, 12:58 pm, Phil Hobbs
pcdhSpamMeSensel... at (no spam) electrooptical.net> wrote:
Hazem wrote:
Please excuse me if this question has been asnwered before. The search
function does not work for older posts on Google Groups anymore.
I am trying to decide whether to acquire a VCSEL or a DFB laser for a
measurement application. The laser will be coupled to a single-mode
fiber, so many of the advantages of VCSEL over DFB diode lasers become
irrelevant. The one criterion I care most about is frequency/
wavelength stability. My understanding is that modern DFB or VCSELs
both have very good stability, but I'd like to know which one is the
best. Wavelength will be in the red/ near IR regions, and I have not
chosen it yet. Again, stability is more important and the choice of
wavelength will be secondary, as long as it is in the long visible or
short IR regions.
Your help is much appreciated.
Hazem
What sort of stability do you need? Barefoot diodes can be 'good' or
'horrible', depending on what your definition of 'good' is.
Cheers
Basically, best available. I read an article somewhere that claimed
+/-0.001nm/degC. I am trying to see if I can get a laser that is
stable enough to make the type of measurement that I need done
feasible. So far, all the lasers I have tested were not stable enough.
Sorry I can't explain what type of measurement I am trying to perform.
I am bound by a non-disclosure agreement. Hopefully after the project
is concluded a paper will be published with all the details.
That isn't a specification I can do much with, sorry.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot nethttp://electrooptical.net- Hide quoted text -
- Show quoted text -
[/quote:4c2b8a46b1]
Thanks anyway.
Hazem |
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| Phil Hobbs... |
| Posted: Tue Oct 06, 2009 10:58 am |
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Guest
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Hazem wrote:
[quote:cefd89d185]Please excuse me if this question has been asnwered before. The search
function does not work for older posts on Google Groups anymore.
I am trying to decide whether to acquire a VCSEL or a DFB laser for a
measurement application. The laser will be coupled to a single-mode
fiber, so many of the advantages of VCSEL over DFB diode lasers become
irrelevant. The one criterion I care most about is frequency/
wavelength stability. My understanding is that modern DFB or VCSELs
both have very good stability, but I'd like to know which one is the
best. Wavelength will be in the red/ near IR regions, and I have not
chosen it yet. Again, stability is more important and the choice of
wavelength will be secondary, as long as it is in the long visible or
short IR regions.
Your help is much appreciated.
Hazem
[/quote:cefd89d185]
What sort of stability do you need? Barefoot diodes can be 'good' or
'horrible', depending on what your definition of 'good' is.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net |
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| Phil Hobbs... |
| Posted: Tue Oct 06, 2009 1:09 pm |
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Guest
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Hazem wrote:
[quote:5f0694ac8c]On Oct 6, 12:58 pm, Phil Hobbs
pcdhSpamMeSensel... at (no spam) electrooptical.net> wrote:
Hazem wrote:
Please excuse me if this question has been asnwered before. The search
function does not work for older posts on Google Groups anymore.
I am trying to decide whether to acquire a VCSEL or a DFB laser for a
measurement application. The laser will be coupled to a single-mode
fiber, so many of the advantages of VCSEL over DFB diode lasers become
irrelevant. The one criterion I care most about is frequency/
wavelength stability. My understanding is that modern DFB or VCSELs
both have very good stability, but I'd like to know which one is the
best. Wavelength will be in the red/ near IR regions, and I have not
chosen it yet. Again, stability is more important and the choice of
wavelength will be secondary, as long as it is in the long visible or
short IR regions.
Your help is much appreciated.
Hazem
What sort of stability do you need? Barefoot diodes can be 'good' or
'horrible', depending on what your definition of 'good' is.
Cheers
Basically, best available. I read an article somewhere that claimed
+/-0.001nm/degC. I am trying to see if I can get a laser that is
stable enough to make the type of measurement that I need done
feasible. So far, all the lasers I have tested were not stable enough.
Sorry I can't explain what type of measurement I am trying to perform.
I am bound by a non-disclosure agreement. Hopefully after the project
is concluded a paper will be published with all the details.
[/quote:5f0694ac8c]
That isn't a specification I can do much with, sorry.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net |
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| Bob May... |
| Posted: Tue Oct 06, 2009 3:03 pm |
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Guest
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Looking at your spec, you may want to consider a bit of a change in the
lightpath to an equal path reference and info beams. With that, any old
laser will do an excellent job of providing the measurement. Unfortunately,
the measurement will be a difference between the various parts of thee
destination rather than a distance from the laser.
--
Bob May
rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net |
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| Hazem... |
| Posted: Tue Oct 06, 2009 3:50 pm |
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Guest
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On Oct 6, 5:03 pm, "Bob May" <bob... at (no spam) nethere.com> wrote:
[quote:54b007654d]Looking at your spec, you may want to consider a bit of a change in the
lightpath to an equal path reference and info beams. With that, any old
laser will do an excellent job of providing the measurement. Unfortunately,
the measurement will be a difference between the various parts of thee
destination rather than a distance from the laser.
--
Bob May
rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
[/quote:54b007654d]
Could you elaborate? I am not sure I understood what you meant. In any
case, I am not doing interferometry or distance measurements.
regards,
Hazem |
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| Bret Cannon... |
| Posted: Tue Oct 06, 2009 9:52 pm |
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Guest
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"Hazem" <hazem.biqaeen at (no spam) gmail.com> wrote in message
news:decc51bf-c0d1-47af-9e03-a4279893262b at (no spam) o21g2000vbl.googlegroups.com...
[quote:72e556cbeb]
Please excuse me if this question has been asnwered before. The search
function does not work for older posts on Google Groups anymore.
I am trying to decide whether to acquire a VCSEL or a DFB laser for a
measurement application. The laser will be coupled to a single-mode
fiber, so many of the advantages of VCSEL over DFB diode lasers become
irrelevant. The one criterion I care most about is frequency/
wavelength stability. My understanding is that modern DFB or VCSELs
both have very good stability, but I'd like to know which one is the
best. Wavelength will be in the red/ near IR regions, and I have not
chosen it yet. Again, stability is more important and the choice of
wavelength will be secondary, as long as it is in the long visible or
short IR regions.
Your help is much appreciated.
Hazem
If you want good stability, there are diode lasers mounted on Peltier[/quote:72e556cbeb]
coolers with thermistors inside the package. With such a diode laser it is
straight forward to stabilize the diode laser temperature to 0.001°C over
periods of hours. Since you don't say anything about your budget, this may
be too expensive.
Bret Cannon |
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| Hazem... |
| Posted: Wed Oct 07, 2009 5:17 am |
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Guest
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On Oct 6, 11:52 pm, "Bret Cannon" <nore... at (no spam) invalid.invalid> wrote:
[quote:15340a8445]"Hazem" <hazem.biqa... at (no spam) gmail.com> wrote in message
news:decc51bf-c0d1-47af-9e03-a4279893262b at (no spam) o21g2000vbl.googlegroups.com...
Please excuse me if this question has been asnwered before. The search
function does not work for older posts on Google Groups anymore.
I am trying to decide whether to acquire a VCSEL or a DFB laser for a
measurement application. The laser will be coupled to a single-mode
fiber, so many of the advantages of VCSEL over DFB diode lasers become
irrelevant. The one criterion I care most about is frequency/
wavelength stability. My understanding is that modern DFB or VCSELs
both have very good stability, but I'd like to know which one is the
best. Wavelength will be in the red/ near IR regions, and I have not
chosen it yet. Again, stability is more important and the choice of
wavelength will be secondary, as long as it is in the long visible or
short IR regions.
Your help is much appreciated.
Hazem
If you want good stability, there are diode lasers mounted on Peltier
coolers with thermistors inside the package. With such a diode laser it is
straight forward to stabilize the diode laser temperature to 0.001°C over
periods of hours. Since you don't say anything about your budget, this may
be too expensive.
Bret Cannon- Hide quoted text -
- Show quoted text -
[/quote:15340a8445]
Yes, I am aware that thermal stabilization is critical, more so for
DFB than for VCSEL, although I doubt you can have 0.001C resolution!
Many DFBs ship with a packaged thermoelectric cooler and thermistor.
My question is: Out of the commercially available DFB or VCSEL
__SYSTEMS__, which have the higher wavelength stability for
wavelengths in the red/near IR region? My budget can be considered
unlimited.
Thanks,
Hazem |
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| DavidM... |
| Posted: Wed Oct 07, 2009 11:35 am |
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Guest
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Hazem wrote:
[quote:4da5b6baa2]On Oct 6, 11:52 pm, "Bret Cannon" <nore... at (no spam) invalid.invalid> wrote:
"Hazem" <hazem.biqa... at (no spam) gmail.com> wrote in message
news:decc51bf-c0d1-47af-9e03-a4279893262b at (no spam) o21g2000vbl.googlegroups.com...
Please excuse me if this question has been asnwered before. The search
function does not work for older posts on Google Groups anymore.
I am trying to decide whether to acquire a VCSEL or a DFB laser for a
measurement application. The laser will be coupled to a single-mode
fiber, so many of the advantages of VCSEL over DFB diode lasers become
irrelevant. The one criterion I care most about is frequency/
wavelength stability. My understanding is that modern DFB or VCSELs
both have very good stability, but I'd like to know which one is the
best. Wavelength will be in the red/ near IR regions, and I have not
chosen it yet. Again, stability is more important and the choice of
wavelength will be secondary, as long as it is in the long visible or
short IR regions.
Your help is much appreciated.
Hazem
If you want good stability, there are diode lasers mounted on Peltier
coolers with thermistors inside the package. With such a diode laser it is
straight forward to stabilize the diode laser temperature to 0.001°C over
periods of hours. Since you don't say anything about your budget, this may
be too expensive.
Bret Cannon- Hide quoted text -
- Show quoted text -
Yes, I am aware that thermal stabilization is critical, more so for
DFB than for VCSEL, although I doubt you can have 0.001C resolution!
[/quote:4da5b6baa2]
what reason do you have to doubt it.
resolution is easy, stability a little harder but it can be realised.
Commercial drivers from Thorlabs or ILX can come close with careful PID
set up and taking time to design your own can hit 0.001C stability. For
greater stability you can put a box withiin a box and control both of
them.
Note a stability of only 0.01C can realise 0.001nm/C, given a typical
temperture tuning coefficient of 0.01nm/C
A single good driver can sit with 0.001nm stability with a 1550nm DFB.
If you want higher stability then you can always lock to an absorbtion line.
[quote:4da5b6baa2]Many DFBs ship with a packaged thermoelectric cooler and thermistor.
My question is: Out of the commercially available DFB or VCSEL
__SYSTEMS__, which have the higher wavelength stability for
wavelengths in the red/near IR region? My budget can be considered
unlimited.
[/quote:4da5b6baa2]
Is linewidth important
can the laser be modulated or does it have to run constant power.
In fact if you have an unlimited budget then I'm pretty sure I can
certainly supply you with a system with that stability just let me know
what you want.
cheers |
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| Phil Hobbs... |
| Posted: Wed Oct 07, 2009 2:44 pm |
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Guest
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DavidM wrote:
[quote:87c87dba47]Hazem wrote:
On Oct 6, 11:52 pm, "Bret Cannon" <nore... at (no spam) invalid.invalid> wrote:
"Hazem" <hazem.biqa... at (no spam) gmail.com> wrote in message
news:decc51bf-c0d1-47af-9e03-a4279893262b at (no spam) o21g2000vbl.googlegroups.com...
Please excuse me if this question has been asnwered before. The search
function does not work for older posts on Google Groups anymore.
I am trying to decide whether to acquire a VCSEL or a DFB laser for a
measurement application. The laser will be coupled to a single-mode
fiber, so many of the advantages of VCSEL over DFB diode lasers become
irrelevant. The one criterion I care most about is frequency/
wavelength stability. My understanding is that modern DFB or VCSELs
both have very good stability, but I'd like to know which one is the
best. Wavelength will be in the red/ near IR regions, and I have not
chosen it yet. Again, stability is more important and the choice of
wavelength will be secondary, as long as it is in the long visible or
short IR regions.
Your help is much appreciated.
Hazem
If you want good stability, there are diode lasers mounted on Peltier
coolers with thermistors inside the package. With such a diode laser
it is
straight forward to stabilize the diode laser temperature to 0.001°C
over
periods of hours. Since you don't say anything about your budget,
this may
be too expensive.
Bret Cannon- Hide quoted text -
- Show quoted text -
Yes, I am aware that thermal stabilization is critical, more so for
DFB than for VCSEL, although I doubt you can have 0.001C resolution!
what reason do you have to doubt it.
resolution is easy, stability a little harder but it can be realised.
Commercial drivers from Thorlabs or ILX can come close with careful PID
set up and taking time to design your own can hit 0.001C stability. For
greater stability you can put a box withiin a box and control both of them.
Note a stability of only 0.01C can realise 0.001nm/C, given a typical
temperture tuning coefficient of 0.01nm/C
A single good driver can sit with 0.001nm stability with a 1550nm DFB.
If you want higher stability then you can always lock to an absorbtion
line.
Many DFBs ship with a packaged thermoelectric cooler and thermistor.
My question is: Out of the commercially available DFB or VCSEL
__SYSTEMS__, which have the higher wavelength stability for
wavelengths in the red/near IR region? My budget can be considered
unlimited.
Is linewidth important
can the laser be modulated or does it have to run constant power.
In fact if you have an unlimited budget then I'm pretty sure I can
certainly supply you with a system with that stability just let me know
what you want.
cheers
[/quote:87c87dba47]
First the OP has to make the laser single mode, because the modes are
much more than 0.001 nm apart. That's what makes the problem as stated
poorly defined. 1 part in 10**6 feedback is enough to make a FP laser
go bananas, and most VCSELs jump between several spatial modes during
turn on, and often afterwards as well. Some have horrible polarization
instability due to being very nearly rotationally symmetric.
A fancy temperature controller isn't a complete solution to the problem
by a long way--not that the OP has actually told us the problem.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net |
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| Jürgen Appel... |
| Posted: Wed Oct 07, 2009 5:11 pm |
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Guest
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Phil Hobbs wrote:
[quote:98451df5b7]First the OP has to make the laser single mode, because the modes are
much more than 0.001 nm apart. That's what makes the problem as stated
poorly defined. 1 part in 10**6 feedback is enough to make a FP laser
go bananas, and most VCSELs jump between several spatial modes during
turn on, and often afterwards as well. Some have horrible polarization
instability due to being very nearly rotationally symmetric.
A fancy temperature controller isn't a complete solution to the problem
by a long way--not that the OP has actually told us the problem.
[/quote:98451df5b7]
100% agreed. And if his budget really is not limited, in my opinion looking
for a simple diode laser is looking the wrong way anyway.
For someone who has no experience at all in laser stabilization I would
recommend a 633nm HeNe-Laser to start with. They have a very narrow gain
bandwidth and so even in the presence of mode jumps the frequency will only
change at most by a few GHz.
For applications where frequency stability really matters, VCSEL lasers are
almost never used. This is mostly because their inherent line width
(typically >20 MHz) is much worse than what you can stabilize other diode
lasers to easily. For only a little tighter requirements this rules out DFB
lasers (mostly >1 MHz) for the same reason.
For the highest stability requirements (what time span are we talking about
actually?) irrespective of costs high-finesse sapphire resonators are used,
which are locked to atomic time standards via a frequency comb...
Cheers,
Jürgen |
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| Bob May... |
| Posted: Wed Oct 07, 2009 10:30 pm |
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Guest
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Stability is usually wanted in eeither of those uses. Note that you don't
have a problem with stability when the beam is being referenced to itself.
Since you're not discussing the application itself, for obcvious reasons, it
becomes a lot more difficult to figure out how to get around the stability
problem.
--
Bob May
rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net |
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| Hazem... |
| Posted: Thu Oct 08, 2009 3:21 am |
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Guest
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On Oct 7, 1:35 pm, DavidM <no... at (no spam) nospam.com> wrote:
[quote:1eae6c813f]Hazem wrote:
On Oct 6, 11:52 pm, "Bret Cannon" <nore... at (no spam) invalid.invalid> wrote:
"Hazem" <hazem.biqa... at (no spam) gmail.com> wrote in message
news:decc51bf-c0d1-47af-9e03-a4279893262b at (no spam) o21g2000vbl.googlegroups.com....
Please excuse me if this question has been asnwered before. The search
function does not work for older posts on Google Groups anymore.
I am trying to decide whether to acquire a VCSEL or a DFB laser for a
measurement application. The laser will be coupled to a single-mode
fiber, so many of the advantages of VCSEL over DFB diode lasers become
irrelevant. The one criterion I care most about is frequency/
wavelength stability. My understanding is that modern DFB or VCSELs
both have very good stability, but I'd like to know which one is the
best. Wavelength will be in the red/ near IR regions, and I have not
chosen it yet. Again, stability is more important and the choice of
wavelength will be secondary, as long as it is in the long visible or
short IR regions.
Your help is much appreciated.
Hazem
If you want good stability, there are diode lasers mounted on Peltier
coolers with thermistors inside the package. With such a diode laser it is
straight forward to stabilize the diode laser temperature to 0.001°C over
periods of hours. Since you don't say anything about your budget, this may
be too expensive.
Bret Cannon- Hide quoted text -
- Show quoted text -
Yes, I am aware that thermal stabilization is critical, more so for
DFB than for VCSEL, although I doubt you can have 0.001C resolution!
what reason do you have to doubt it.
resolution is easy, stability a little harder but it can be realised.
Commercial drivers from Thorlabs or ILX can come close with careful PID
set up and taking time to design your own can hit 0.001C stability. For
greater stability you can put a box withiin a box and control both of
them.
Note a stability of only 0.01C can realise 0.001nm/C, given a typical
temperture tuning coefficient of 0.01nm/C
A single good driver can sit with 0.001nm stability with a 1550nm DFB.
If you want higher stability then you can always lock to an absorbtion line.
Many DFBs ship with a packaged thermoelectric cooler and thermistor.
My question is: Out of the commercially available DFB or VCSEL
__SYSTEMS__, which have the higher wavelength stability for
wavelengths in the red/near IR region? My budget can be considered
unlimited.
Is linewidth important
can the laser be modulated or does it have to run constant power.
In fact if you have an unlimited budget then I'm pretty sure I can
certainly supply you with a system with that stability just let me know
what you want.
cheers- Hide quoted text -
- Show quoted text -
[/quote:1eae6c813f]
Dear David,
Thanks for all the good information!
I am curious, how do you in practice lock a diode laser to an emission
line? Do you use an HeNe laser to inject the diode laser? I tested
several temperature-stabilized HeNe lasers but I still saw what
appeared to be mode hopping in the output. Maybe the temperature
control systems were not that good, but I suspect controlling a laser
tube of that size uniformly is not easy.
To answer your questions, the laser will not be modulated. At least
this is not a design requirement at this time. Wavelength stability is
the most important consideration, however a large linewidth would also
be useful in reducing speckle and interefrence effects, although these
two considerations might be in conflict, as for example in single-
frequency operation.
I am in the process of compiling a components list for my employer who
will have to approve the purchase. I might get in touch with you
within the next few weeks to discuss supplying us with the parts. Do
you have a business websiote?
Hazem |
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