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Looking to repair a fiber optic cable on a MPS-8033

J

Jay

Jan 1, 1970
0
Hello all,

I have a piece of test equipment that needs repair, and which goes beyond
my skills in the field of electronics. It's a 1550nm ILX Lightwave
MPS-8033/03, which has had a botched repair attempt - The fiber optic
cable between the laser and the front panel was severely kinked (pretty
much 180 degrees!), and no longer appears to conduct light.

The instrument can be seen here:
http://www.ilxlightwave.com/propgs/fiber_optic_instruments_8033.html

The laser is from Lucent technologies, and looking at a PDF of the device
it would appear that the 32" of fiber optic cable comes with the laser -
in other words, not detachable. So, basically, I'm looking for a
professional in the US (I am located in MA) who can cut about 3" of the
cable out, then splice it, as I have neither the tools nor the knowledge
to do so myself. I would also be interested in any tips on reasonably
priced repair facilities that do this kind of work. (The manufacturer
wants a ridiculous amount for the repair.)

If interested, please email 66gtojayw AT comcast.net, or reply here in the
groups. Thanks!
 
S

Sam Goldwasser

Jan 1, 1970
0
Jay said:
Hello all,

I have a piece of test equipment that needs repair, and which goes beyond
my skills in the field of electronics. It's a 1550nm ILX Lightwave
MPS-8033/03, which has had a botched repair attempt - The fiber optic
cable between the laser and the front panel was severely kinked (pretty
much 180 degrees!), and no longer appears to conduct light.

The instrument can be seen here:
http://www.ilxlightwave.com/propgs/fiber_optic_instruments_8033.html

The laser is from Lucent technologies, and looking at a PDF of the device
it would appear that the 32" of fiber optic cable comes with the laser -
in other words, not detachable. So, basically, I'm looking for a
professional in the US (I am located in MA) who can cut about 3" of the
cable out, then splice it, as I have neither the tools nor the knowledge
to do so myself. I would also be interested in any tips on reasonably
priced repair facilities that do this kind of work. (The manufacturer
wants a ridiculous amount for the repair.)

With the proper equipment (fusion splicer, some experience) this shouldn't
be difficult.

However, when you say "kinked 180 degrees", are you sure it's really broken
internally? That's the only way it would fail. How tight is the kink? And
how did it get kinked? A dead laser would produce the same symptoms, right?

Will also post to sci.optics .

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.
 
J

Jay

Jan 1, 1970
0
With the proper equipment (fusion splicer, some experience) this shouldn't
be difficult.

Neither of which I have... :) ($18K USD. Ouch!)
However, when you say "kinked 180 degrees", are you sure it's really broken
internally? That's the only way it would fail. How tight is the kink? And
how did it get kinked?

Well, this instrument was originally missing it's key. An overzealous
"tech" [cough, cough] figured he/she could replace the keyswitch, and
dis-assembled and removed the front panel of the equipment. In order to do
this, they pulled the nicely looped fiber optic cable hard against two of
the ties holding the loop against the solder side of the lower circuit
board. Now it's come to MY bench for repair... I don't know how I can be
sure that it's broken internally, but it is severely deformed and
stretched looking. If one were to take a piece of really thin fiber and
pull it tight around the radius of a pin's diameter, that would pretty
much describe the cable - kinks are in two places about two inches apart.
Using an optical power meter tuned to 1550nm I was unable to get any
reading, no matter how I tried to straighten the kinks.
A dead laser would produce the same symptoms, right?

Yeah, that's always a possibility. I'd use a scope to check the laser
drive, but I've no idea what it would look like as this is my first
experience with this type of stuff. The laser does get comfortably warm to
the touch after a few minutes and seems to vary thermally depending on the
output power I dial in, so I'm ASSuming and hoping that it's still
functioning. ;) Given those conditions, would the laser appear to be
working?

I don't think that Lucent is making these devices anymore, but the laser
looks similar to the device on this website:
http://www.intenseco.com/products/inslam/?View=S
Will also post to sci.optics .

Thanks Sam.
 
S

Sam Goldwasser

Jan 1, 1970
0
Jay said:
Neither of which I have... :) ($18K USD. Ouch!)

Well, maybe $2-3K on eBay. :) At the bottom of the dot.bomb, they were
going for under $1K. The experience might cost more though. :)
However, when you say "kinked 180 degrees", are you sure it's really broken
internally? That's the only way it would fail. How tight is the kink? And
how did it get kinked?

Well, this instrument was originally missing it's key. An overzealous
"tech" [cough, cough] figured he/she could replace the keyswitch, and
dis-assembled and removed the front panel of the equipment. In order to do
this, they pulled the nicely looped fiber optic cable hard against two of
the ties holding the loop against the solder side of the lower circuit
board. Now it's come to MY bench for repair... I don't know how I can be
sure that it's broken internally, but it is severely deformed and
stretched looking. If one were to take a piece of really thin fiber and
pull it tight around the radius of a pin's diameter, that would pretty
much describe the cable - kinks are in two places about two inches apart.

Doesn't sound good. Especially the stretched part. Fibers will bend around
a small radius without breaking, but not a pin diameter.
Using an optical power meter tuned to 1550nm I was unable to get any
reading, no matter how I tried to straighten the kinks.


Yeah, that's always a possibility. I'd use a scope to check the laser
drive, but I've no idea what it would look like as this is my first
experience with this type of stuff. The laser does get comfortably warm to
the touch after a few minutes and seems to vary thermally depending on the
output power I dial in, so I'm ASSuming and hoping that it's still
functioning. ;) Given those conditions, would the laser appear to be
working?

Likely working but no guarantee.
I don't think that Lucent is making these devices anymore, but the laser
looks similar to the device on this website:
http://www.intenseco.com/products/inslam/?View=S

Someone should be able to point you to a place that has a fusion splicer.

But to do a one-off repair at a reasonable price, may take a friend of a
friend....

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.
 
L

Lostgallifreyan

Jan 1, 1970
0
Likely working but no guarantee.

At risk of going beyond my ground.....

That laser seems to be accepting a drive correctly, but the output might do
one of two things, either it will have died by retroreflection from a large
return of light from the damaged point in the fibre, or it will be active,
because energy can get out (as heat) without returning to kill the diode.

If this laser is powerful enough, you might be able to detect heat at the
damaged point in the fibre. Try taping it to a small Peltier (that has lots
of couples in it) and seeing if you see a few millivolts on the Peltier
wires when you switch on the laser. Even a 5 mW laser ought to read
something consistent if you control for ambient heat and watch a few
switching transitions.

The one thing the Peltier test can't tell you is if the laser is low power,
and the fibre is reflecting energy back to the diode, it can't tell you if
the diode is dead or not, but for power greater than around 50 mW it should
be a reliable test.
 
J

Jürgen Appel

Jan 1, 1970
0
Sam said:
However, when you say "kinked 180 degrees", are you sure it's really
broken
internally? That's the only way it would fail. How tight is the kink?
And how did it get kinked? A dead laser would produce the same symptoms,
right?

If you look at the fiber with an infrared viewer and it is the fiber that is
is broken and not the laser, you should see a lot of scattered light that
emanates from the fiber core at the breaking point.

Cheers,
Jürgen
 
H

heruursciences

Jan 1, 1970
0
Might want to try finding the laser diode inside on ebay. I've seen a
lot of DFB diodes in that range on there. Other than that you're only
option is to get the fiber spliced. It's really not that difficult if
you cleanly cleave it and use a fusion splicer. The part that sucks is
that one of the pezio positioners on my splicer is fried.
 
J

Jay

Jan 1, 1970
0
At risk of going beyond my ground.....

That laser seems to be accepting a drive correctly, but the output might do
one of two things, either it will have died by retroreflection from a large
return of light from the damaged point in the fibre, or it will be active,
because energy can get out (as heat) without returning to kill the diode.

Hopefully, the latter is the case. I had no idea that the light could
reflect back into the diode and destroy it... As a side note, the folks at
ILX refused to do the splice work, and would only replace the entire laser
assembly at a cost of minimum cost of $1500. Nice support!

If this laser is powerful enough, you might be able to detect heat at the
damaged point in the fibre. Try taping it to a small Peltier (that has lots
of couples in it) and seeing if you see a few millivolts on the Peltier
wires when you switch on the laser. Even a 5 mW laser ought to read
something consistent if you control for ambient heat and watch a few
switching transitions.

The one thing the Peltier test can't tell you is if the laser is low power,
and the fibre is reflecting energy back to the diode, it can't tell you if
the diode is dead or not, but for power greater than around 50 mW it should
be a reliable test.

At this point, I'm a bit hesitant to power up the instrument again. I
received a response by email, and may have a contact who can do the work
for me, he's stated that if the cable is single mode fiber, it shouldn't
be a difficult operation. I'll follow up when it's done and report the
outcome for any who are interested. Thanks to everyone who took the time
to respond!
 
W

wy

Jan 1, 1970
0
With the proper equipment (fusion splicer, some experience) this shouldn't
be difficult.

However, when you say "kinked 180 degrees", are you sure it's really broken
internally? That's the only way it would fail. How tight is the kink? And
how did it get kinked? A dead laser would produce the same symptoms, right?

Will also post to sci.optics .

--- sam | Sci.Electronics.Repair FAQ:http://www.repairfaq.org/
Repair | Main Table of Contents:http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ:http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites:http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.




- Show quoted text -- Hide quoted text -

- Show quoted text -

I had a broken-fiber problem before on another type of laser (SM
fiber). And we had it spliced. Using a fiber fault finder, the
engineer located the fault within 2mm. Not bad at all. The resulting
fiber is 1" shorter with a little power drop (never calibrated it
carefully) from the laser. It costed us only $50.
 
J

Jay

Jan 1, 1970
0
I had a broken-fiber problem before on another type of laser (SM
fiber). And we had it spliced. Using a fiber fault finder, the
engineer located the fault within 2mm. Not bad at all. The resulting
fiber is 1" shorter with a little power drop (never calibrated it
carefully) from the laser. It costed us only $50.

Out of curiosity (and future reference), where did you have the work done?
 
R

ROITHNER LASERTECHNIK

Jan 1, 1970
0
Hi Sam,

what has happend with alt.lasers?!!

A. Roithner
 
S

Sam Goldwasser

Jan 1, 1970
0
ROITHNER LASERTECHNIK said:
Hi Sam,

what has happend with alt.lasers?!!

Nothing. :)

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.
 
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