Pretty diffraction pattern at end of laser fiber

[Avi Jacob]

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Hi all,

We have a 3DFRAP system that feeds a 488 laser to the microscope through a
fiber optic cable (Linos).
Currently the laser will not photo-bleach our AOI. By eye, there is still a
nice pretty blue light coming out of the objective, and the calibration is
working, however, when I disconnect the fiber from the microscope and shine
on the table, instead of a nice beam, I am getting a weird, splattered
diffraction pattern. (It's actually very pretty).

The coupler is aligned, so that is not the problem.
I flipped the direction of the fiber, and the pattern seemed to disappear a
bit, and the center became stronger, but it was still not a perfect beam
and still had splatter.

I suspect the culprit is the fiber itself. I cannot find another fiber that
fits our coupler, to confirm that that is the problem.
A 200x fiber scope did not show anything, and we cleaned both ends of the
fiber - did not help.

Any way to test the fiber?
Is it probable that the fiber is cracked or broken somewhere?

Thanks for any advice.

Best,
Avi J.

[EricMarino]

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The tip may just need to polished. You can purchase a kit from ThorLabs.


Eric Marino
Senior Imaging Specialist
Program in Cellular and Molecular Medicine
Boston Children's Hospital
200 Longwood Ave
WAB Room 133D
Boston, MA 02115
Lab: 617 713-8885
Cell: 617 913-9647
[hidden email]<mailto:[hidden email]>



On Jul 23, 2013, at 2:39 PM, Avi Jacob <[hidden email]<mailto:[hidden email]>> wrote:

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Hi all,

We have a 3DFRAP system that feeds a 488 laser to the microscope through a
fiber optic cable (Linos).
Currently the laser will not photo-bleach our AOI. By eye, there is still a
nice pretty blue light coming out of the objective, and the calibration is
working, however, when I disconnect the fiber from the microscope and shine
on the table, instead of a nice beam, I am getting a weird, splattered
diffraction pattern. (It's actually very pretty).

The coupler is aligned, so that is not the problem.
I flipped the direction of the fiber, and the pattern seemed to disappear a
bit, and the center became stronger, but it was still not a perfect beam
and still had splatter.

I suspect the culprit is the fiber itself. I cannot find another fiber that
fits our coupler, to confirm that that is the problem.
A 200x fiber scope did not show anything, and we cleaned both ends of the
fiber - did not help.

Any way to test the fiber?
Is it probable that the fiber is cracked or broken somewhere?

Thanks for any advice.

Best,
Avi J.

[Matthew Nicholas-2]

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Hi Avi,
I had a similar problem with a fiber a few years ago. I that case it was the result of someone inserting it incorrectly in an FC connector, and that end was visibly damaged. You might want to inspect the two ends of the fiber (e.g. using an eyepiece from a microscope, or even a low-power objective) and see if they look the same. Unfortunately I don't recall exactly what the defect looked like in our case, but I do recall it was quite obvious when compared to the undamaged end.

Cheers,
Matt

On Jul 23, 2013, at 2:25 PM, Avi Jacob <[hidden email]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Hi all,
>
> We have a 3DFRAP system that feeds a 488 laser to the microscope through a
> fiber optic cable (Linos).
> Currently the laser will not photo-bleach our AOI. By eye, there is still a
> nice pretty blue light coming out of the objective, and the calibration is
> working, however, when I disconnect the fiber from the microscope and shine
> on the table, instead of a nice beam, I am getting a weird, splattered
> diffraction pattern. (It's actually very pretty).
>
> The coupler is aligned, so that is not the problem.
> I flipped the direction of the fiber, and the pattern seemed to disappear a
> bit, and the center became stronger, but it was still not a perfect beam
> and still had splatter.
>
> I suspect the culprit is the fiber itself. I cannot find another fiber that
> fits our coupler, to confirm that that is the problem.
> A 200x fiber scope did not show anything, and we cleaned both ends of the
> fiber - did not help.
>
> Any way to test the fiber?
> Is it probable that the fiber is cracked or broken somewhere?
>
> Thanks for any advice.
>
> Best,
> Avi J.

[Craig Brideau]

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Is the fiber single mode or multi mode?

Craig
On 2013-07-23 12:39 PM, "Avi Jacob" <[hidden email]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Hi all,
>
> We have a 3DFRAP system that feeds a 488 laser to the microscope through a
> fiber optic cable (Linos).
> Currently the laser will not photo-bleach our AOI. By eye, there is still a
> nice pretty blue light coming out of the objective, and the calibration is
> working, however, when I disconnect the fiber from the microscope and shine
> on the table, instead of a nice beam, I am getting a weird, splattered
> diffraction pattern. (It's actually very pretty).
>
> The coupler is aligned, so that is not the problem.
> I flipped the direction of the fiber, and the pattern seemed to disappear a
> bit, and the center became stronger, but it was still not a perfect beam
> and still had splatter.
>
> I suspect the culprit is the fiber itself. I cannot find another fiber that
> fits our coupler, to confirm that that is the problem.
> A 200x fiber scope did not show anything, and we cleaned both ends of the
> fiber - did not help.
>
> Any way to test the fiber?
> Is it probable that the fiber is cracked or broken somewhere?
>
> Thanks for any advice.
>
> Best,
> Avi J.
>

[Avi Jacob]

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http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
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I am actually not sure if it's single mode or multi mode. The laser is a
Cobolt MLD 488.
This is the fiber, if you can interpret this:
Linos FIBSM-BVIS-3.0-SD5-FC0-FC0
FIC50/XYZ-1.1

Avi J.




On Wed, Jul 24, 2013 at 2:25 AM, Craig Brideau <[hidden email]>wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Is the fiber single mode or multi mode?
>
> Craig
> On 2013-07-23 12:39 PM, "Avi Jacob" <[hidden email]> wrote:
>
> > *****
> >
> >
> > Hi all,
> >
> > We have a 3DFRAP system that feeds a 488 laser to the microscope through
> a
> > fiber optic cable (Linos).
> > Currently the laser will not photo-bleach our AOI. By eye, there is
> still a
> > nice pretty blue light coming out of the objective, and the calibration
> is
> > working, however, when I disconnect the fiber from the microscope and
> shine
> > on the table, instead of a nice beam, I am getting a weird, splattered
> > diffraction pattern. (It's actually very pretty).
> >
> >
> > I suspect the culprit is the fiber itself. I cannot find another fiber
> that
> > fits our coupler, to confirm that that is the problem.
> > A 200x fiber scope did not show anything, and we cleaned both ends of the
> > fiber - did not help.
> >
> > Any way to test the fiber?
> > Is it probable that the fiber is cracked or broken somewhere?
> >
> > Thanks for any advice.
> >
> > Best,
> > Avi J.
> >
>

[Zdenek Svindrych]

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Hi Avi,

according to this:
http://www.linos.com/pages/mediabase/original/systemsorderinginformation_
3191.pdf
it's a single mode fiber, so the output beam should be perfect. I would
suspect the output fiber-end face or whatever there is at the end of the
fiber.
You may try to reverse the direction of the fiber (unless you already did
that), though it may be difficult to maintain the alignment. After plugging
the fiber the other way round you should get nice beam, but you won't get
more power, eventually you would need to have the fiber replaced...

Regards,

zdenek

---------------------------
Zdenek Svindrych
The First Faculty of Medicine
Charles University in Prague
Czech Republic
---------------------------



---------- Původní zpráva ----------
Od: Avi Jacob <[hidden email]>
Datum: 24. 7. 2013
Předmět: Re: Pretty diffraction pattern at end of laser fiber

"*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

I am actually not sure if it's single mode or multi mode. The laser is a
Cobolt MLD 488.
This is the fiber, if you can interpret this:
Linos FIBSM-BVIS-3.0-SD5-FC0-FC0
FIC50/XYZ-1.1

Avi J.




On Wed, Jul 24, 2013 at 2:25 AM, Craig Brideau <[hidden email]>
wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Is the fiber single mode or multi mode?
>
> Craig
> On 2013-07-23 12:39 PM, "Avi Jacob" <[hidden email]> wrote:
>
> > *****
> >
> >
> > Hi all,
> >
> > We have a 3DFRAP system that feeds a 488 laser to the microscope through
> a
> > fiber optic cable (Linos).
> > Currently the laser will not photo-bleach our AOI. By eye, there is
> still a
> > nice pretty blue light coming out of the objective, and the calibration
> is
> > working, however, when I disconnect the fiber from the microscope and
> shine
> > on the table, instead of a nice beam, I am getting a weird, splattered
> > diffraction pattern. (It's actually very pretty).
> >
> >
> > I suspect the culprit is the fiber itself. I cannot find another fiber
> that
> > fits our coupler, to confirm that that is the problem.
> > A 200x fiber scope did not show anything, and we cleaned both ends of

the

> > fiber - did not help.
> >
> > Any way to test the fiber?
> > Is it probable that the fiber is cracked or broken somewhere?
> >
> > Thanks for any advice.
> >
> > Best,
> > Avi J.
> >
>"

[Larson Jeffrey M.]

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http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
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Hi all,
We use some very powerful CW lasers at Nikon and on occasion have seen a 'pretty diffraction pattern' in the light coming through a single mode optical fiber that cannot be easily removed by cleaning the tip.  In our experience, it has been caused by melting of the cladding around the fiber core.  There are a few things to consider to mitigate the problem.  The existing fiber can be lapped and polished to remove the damage.  Use the freshly polished end on the insertion side if you don't have a focusable collimating lens at the output.  When you replace the fiber, consider replacing it with a 3.5um core fiber.  3.5um core fibers work fine at 488nm.  This way laser power will be spread out over a greater area at the tip and melting will be less likely to occur.  If possible, consider attenuating laser power before coupling into the fiber.  You may find that you have more than adequate power for your needs below the fiber damage threshold.
Regards,
Jeff Larson

-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Avi Jacob
Sent: Wednesday, July 24, 2013 3:22 AM
To: [hidden email]
Subject: Re: Pretty diffraction pattern at end of laser fiber

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

I am actually not sure if it's single mode or multi mode. The laser is a Cobolt MLD 488.
This is the fiber, if you can interpret this:
Linos FIBSM-BVIS-3.0-SD5-FC0-FC0
FIC50/XYZ-1.1

Avi J.




On Wed, Jul 24, 2013 at 2:25 AM, Craig Brideau <[hidden email]>wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Is the fiber single mode or multi mode?
>
> Craig
> On 2013-07-23 12:39 PM, "Avi Jacob" <[hidden email]> wrote:
>
> > *****
> >
> >
> > Hi all,
> >
> > We have a 3DFRAP system that feeds a 488 laser to the microscope
> > through
> a
> > fiber optic cable (Linos).
> > Currently the laser will not photo-bleach our AOI. By eye, there is
> still a
> > nice pretty blue light coming out of the objective, and the
> > calibration
> is
> > working, however, when I disconnect the fiber from the microscope
> > and
> shine
> > on the table, instead of a nice beam, I am getting a weird,
> > splattered diffraction pattern. (It's actually very pretty).
> >
> >
> > I suspect the culprit is the fiber itself. I cannot find another
> > fiber
> that
> > fits our coupler, to confirm that that is the problem.
> > A 200x fiber scope did not show anything, and we cleaned both ends
> > of the fiber - did not help.
> >
> > Any way to test the fiber?
> > Is it probable that the fiber is cracked or broken somewhere?
> >
> > Thanks for any advice.
> >
> > Best,
> > Avi J.
> >
>

Jeffrey M Larson
Confocal Systems Product Manager

Nikon Instruments Inc.
1300 Walt Whitman Road
Melville NY 11747-3064

Office: 631-547-8540    Fax: [phone]
Mobile: [phone]
[hidden email]       www.nikoninstruments.com


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