Is there an alternative to hydrofluoric acid for etching optical fibers?

[Vicki Thompson]

I am currently reducing the diameter of optical fibers by etching with
hydrofluoric acid (HF) and have just recently found out how dangerous it
is. The article I read stated that contact by the acid of only 2% of the
body is fatal. I want to know if there is a safer alternative to HF for
etching fibers. Thanks.

Vicki Thompson

[Jim Freeze]

HF is very dangerous in that it deadens the nerve endings and so, as
it works its way to your bones and turns them into jelly, you don't
feel a thing, unlike sulfuric or hydrochloric acid.

However, 2% is not fatal, but probably wouldn't do you any good,
especially under prolonged exposure.
We typically used 10-12% for our etching. We are careful, but 10% is
certainly not as scary as the 51% that we used to make our solutions.

Currently I don't know of any other substance that disolves silica.
However, if you are trying to reach the energy in the core, there are
other methods to do this. Lapping or Core diffusion are a couple.
If you are making gratings, United Technologies uses UV lasers and
writes them into the fiber core, hence etching is not required.
Good Luck
Jim Freeze

[Alan Shinn]

> Vicki Thompson <thom...@ncaur1.ncaur.gov> wrote:
>
> >I am currently reducing the diameter of optical fibers by etching with
> >hydrofluoric acid (HF) and have just recently found out how dangerous it
> >is. The article I read stated that contact by the acid of only 2% of the
> >body is fatal. I want to know if there is a safer alternative to HF for
> >etching fibers. Thanks.
>
> >Vicki Thompson

Vicki:
This post will be of limited value due to my leaky brain. However, I will
assure you that there are flouride based etchants that work for glass (so
they may work for silica) that are much tamer than the acid. I don't know
where to point you to search except for perhaps the hobby or jewelry
trade. Maybe search under glass etchants.
Also, hot concentrated NaOH or KOH might do. I am almost sure that the
fused KOH or NaOH will eat silica but may be too fast.
By the way, you are right about HF being *very* nasty.

--
Looking forward:
Alan Shinn als...@sirius.com

[Adam Whybrew]

Vicki Thompson <thom...@ncaur1.ncaur.gov> wrote:
>I am currently reducing the diameter of optical fibers by etching with
>hydrofluoric acid (HF) and have just recently found out how dangerous it
>is. The article I read stated that contact by the acid of only 2% of the
>body is fatal. I want to know if there is a safer alternative to HF for
>etching fibers. Thanks.
>
>Vicki Thompson
>

This reply does not answer your question, and please forgive me for
replying on the basis of my experiences in the UK.

Who is requiring you to work with HF without training you in how dangerous
it is? In this country your employer just might be sent to prison for that!
Do you, for example, have HF burn jelly available? Do you have a safety
officer?

Forgive me if I've misinterpreted what you have written - but what I read
made me angry.

Incidentally, why are you reducing the diameter of your fibres?

Adam

[R Cannon]

In article <4n7gsm$6...@sunca.ncaur.gov>, thom...@ncaur1.ncaur.gov says...

>
>I am currently reducing the diameter of optical fibers by etching with
>hydrofluoric acid (HF) and have just recently found out how dangerous it
>is. The article I read stated that contact by the acid of only 2% of the
>body is fatal. I want to know if there is a safer alternative to HF for
>etching fibers. Thanks.
>
>Vicki Thompson
>

I am not certain where I heard this, but I seem to recall having heard that
a strong base will etch fibers without giving them a "frosted" appearance.
I don't know if this is true, but if so, perhaps a strong base will work as
well. (probably far too slow, however)

If you are tring to access the core, I have read some articles on methods of
fabrication to polish to the core. Pot the fiber onto the surface of a large
lens (used only as a curved substrate) and then use conventional polishing
techniques. Or you could just get some D fiber from Andrew. The thermal
diffusion is a good idea if your fiber has enough Ge in it also.

Whatever you do, BE CAREFUL!

[akldb]

One can etch optical fibres with an eximer laser. This is done
routinely by

Exitech Ltd.
Hanborough Business Park,
Long Hanborough Oxon OX7 2LH U.K.
+441 993 88 3324 tel
+44 1993 88 3334 fax

Consequently one can etch the fibre with codes at interval along
the length making identification of individual fibres easy.

Tony

[rws100]

> > Vicki Thompson <thom...@ncaur1.ncaur.gov> wrote:
> >
> > >I am currently reducing the diameter of optical fibers by etching with
> > >hydrofluoric acid (HF) and have just recently found out how dangerous it
> > >is. The article I read stated that contact by the acid of only 2% of the
> > >body is fatal. I want to know if there is a safer alternative to HF for
> > >etching fibers. Thanks.
> >
> > >Vicki Thompson
>

> Vicki:
> This post will be of limited value due to my leaky brain. However, I will
> assure you that there are flouride based etchants that work for glass (so

> they may work for silica)...

_Snip_

> --
> Looking forward:
> Alan Shinn als...@sirius.com

I don't know if silica is the same as ordinary glass either, with
respect to materials that will etch the stuff, but Universal
Photonics(...516-935-4000 they sell optical polishing supplies and such...)
sells what they call "cleaning crystals " (sent thru regular mail
no less !) that will etch Pyrex at a modest rate. Recently there
was go-around on this subject that I believe also mentioned maybe
ammonium-bifloride (?) although I believe that that was more
generically on optical glass. For whatever it is worth...

Robert W. Smith
Penn State Applied Research Lab

[Elliot M Burke]

In <DrG7t...@lexmark.com> rca...@lexmark.com (R Cannon) writes:
>
>In article <4n7gsm$6...@sunca.ncaur.gov>, thom...@ncaur1.ncaur.gov says...
>>

>>I am currently reducing the diameter of optical fibers by etching with
>>hydrofluoric acid (HF) and have just recently found out how dangerous it
>>is. The article I read stated that contact by the acid of only 2% of the
>>body is fatal. I want to know if there is a safer alternative to HF for
>>etching fibers. Thanks.
>>
>>Vicki Thompson
>>

>I am not certain where I heard this, but I seem to recall having heard
that
>a strong base will etch fibers without giving them a "frosted"
appearance.
>I don't know if this is true, but if so, perhaps a strong base will
work as
>well. (probably far too slow, however)
>

Quartz crystals are grown by hydrothermal process in a alkali solution.
This is done in what amounts to a bomb, so it may not be practical as
a labratory process.

Elliot Burke
HighTide Instruments
ell...@ix.netcom.com

[_ _ _ _ _ MARK W. LUND _ _ _ _ _]

> is. The article I read stated that contact by the acid of only 2% of the
> body is fatal. I want to know if there is a safer alternative to HF for
> etching fibers. Thanks.
>
> Vicki Thompson
>

--
Mark W. Lund, PhD

Vicki,
I will buck the trend and say that HF is dangerous but not
as dangerous as many things (for example trying to etch with
molten NaOH). It is what semiconductor fabs use to remove
SiO2 from wafers (in patterning for example) and thousands
of people handle it safely in such facilities every day.

So...treat it with respect. Get the proper equipment, and
antidotes. Then do your experiment. Nothing works like
HF, unless it's BOE (Buffered oxide etch--HF + buffers).

best regards
mark

Director >> Soft X-ray Web page http://www.moxtek.com<<
MOXTEK, Inc. *************************************************
Orem UT 84057 **"Soft x-rays in the 21st Century" conference **
801-225-0930 ** 8-11 January 1996, Midway Utah **
FAX 801-221-1121 ** http://volta.byu.edu/xray/info.html **
lu...@xray.byu.edu *************************************************

"He spoke with a certain what-is-it in his voice, and I could see
that, if not actually disgruntled, he was far from being gruntled."

[cha...@seanet.com]

On 5/16/96 6:19AM, in message <4nehdm$j...@dfw-ixnews9.ix.netcom.com>, Elliot M
Burke <ell...@ix.netcom.com> wrote:

> In <DrG7t...@lexmark.com> rca...@lexmark.com (R Cannon) writes:
> >
> >In article <4n7gsm$6...@sunca.ncaur.gov>, thom...@ncaur1.ncaur.gov says...
> >>
> >>I am currently reducing the diameter of optical fibers by etching with
> >>hydrofluoric acid (HF) and have just recently found out how dangerous it

> >>is. The article I read stated that contact by the acid of only 2% of the
> >>body is fatal. I want to know if there is a safer alternative to HF for
> >>etching fibers. Thanks.
> >>
> >>Vicki Thompson
> >>

> >I am not certain where I heard this, but I seem to recall having heard
> that
> >a strong base will etch fibers without giving them a "frosted"
> appearance.
> >I don't know if this is true, but if so, perhaps a strong base will
> work as
> >well. (probably far too slow, however)
> >
> Quartz crystals are grown by hydrothermal process in a alkali solution.
> This is done in what amounts to a bomb, so it may not be practical as
> a labratory process.
>
> Elliot Burke
> HighTide Instruments
> ell...@ix.netcom.com

HF is not 'fatal' per se. It is actually a very weak acid. The danger it
presents is that it does not 'burn' skin like HCl or HNO3 does. It however,
penetrates the skin and seeks out the calcium in your bones. Treatment is
extremely painful. If you are careful with it (i.e. wear appropriate
protection! Read the MSDS!), you should be OK. Just use caution and common
sense. I speak from first hand experience.

You may also try KOH, about 70% in water as an alternative. It etches a little
slower but it behaves more like traditional acids when it comes in contact with
skin (Ouch!)

Chak Aw
cha...@seanet.com

[George Arndt]

Having left strongly alkaline solutions in lab glassware too long, I can
assure you that the surface of glass does not etch smoothly. In fact, HF
has been used to produce a fine-grained matt surface on ground glasses
for cameras. I think this is caused by the varying solubilities of the
the constituents of glass, which is after all only a solid solution.

Many years ago someone was offering a glass etching kit which was free of
HF. It might also have been intended for etching crystals for control of
r-f oscillators.

I wish I could be of more help, but this might be a start. After all, no
one wants to get involved with HF if he (or she) can avoid it.

---G Arndt

[Elliot M Burke]

In <1996May24.2...@lafn.org> as...@lafn.org (George Arndt) writes:
>
>
>
>>You may also try KOH, about 70% in water as an alternative. It etches a
little
>>slower but it behaves more like traditional acids when it comes in contact
with
>>skin (Ouch!)
>>
>>Chak Aw
>>cha...@seanet.com
>>
>Having left strongly alkaline solutions in lab glassware too long, I
can
>assure you that the surface of glass does not etch smoothly. In fact,
HF
>has been used to produce a fine-grained matt surface on ground glasses

>for cameras. I think this is caused by the varying solubilities of the

>the constituents of glass, which is after all only a solid solution.
>
>

It is possible to etch glass smoothly. The proper mix of acids will
smooth a ground surface and make it shiny. I watched this process but
couldn't get the mixture info from the people doing it. They told me
that some crystal chandeliers were ground and acid polished- this might
be true. Nowadays they are probably molded.