A PZT is a piezoeletric transducer, i.e., a device containing a piezo
which can do some mechanical displacement controled by a (usually high)
voltage.

A PZT can be used to stretch an optical fiber, with the effect that the
optical path length is somewhat modified. This is sometimes used e.g.
to wavelength-tune a fiber laser, or to adjust a path length difference
in an interferometer-type apparatus. I would expect the birefringence
of a PM fiber also to react to this to some extent. However, the
magnitude of this effect will be quite small compared to the natural
birefringence of this fiber, and will strongly depend on how exactly
the PZT acts on the fiber. So whether it is feasible will depend on how
much stretching you need, and will require the development of a
suitable way of attaching the PZT to the fiber.

------------------------------
R=FCdiger Paschotta
RP Photonics Consulting GmbH
www.rp-photonics.com

From:	Alvin
Subject:	Re: What's PZT
Date:	17 Jan 2005 18:05:44 -0800

Could you please show me a little bit detail about the magnetic method?
What components are needed?

thanks,
alvin

From:	A. E. Siegman
Subject:	Re: What's PZT
Date:	Tue, 18 Jan 2005 11:00:44 -0800

> Could you please show me a little bit detail about the magnetic method?
> What components are needed?
>
> thanks,
> alvin

Look at how a conventional loudspeaker works -- then try applying the
same ideas to your motion or pressure problems.

From:	Alvin
Subject:	Re: What's PZT
Date:	15 Jan 2005 09:20:39 -0800

Thanks all for kindly reply.
Then any approaches to increase the tunablity of birefringence
electro-optically

Thanks !!

From:	Rainer Engelbrecht
Subject:	Re: What's PZT
Date:	Mon, 17 Jan 2005 10:34:53 +0100

In non-PM fibers you could use a PZT to apply a pressure perpenicular on
the axis of the fiber, rather than stretch along the fiber axis. The
stress induced birefrigence could be used for polarization controll.
There is a device made by Oz Optics that uses manually applied pressure
and a rotation stage for polarization controll. Works fine.

In priciple, two mutually otrhogonal PZT a slightly different locations
should allow to impose an electrically controlable birefrigence and thus
retardance in two axes to give full polarization controllwithout any
further mechanical degree of freedom. Or am I missing something?

Do not know if this works fine on PM fibers, because the intrinsic
birefrigence is rather strong in this fibers.

Rainer

alvin@rabbito.org schrieb:

> Would anyone tell me the working principle of PZT, is it feasible to
> use it to control birefringence of PM fiber?
>
> thanks thanks

From:	A. E. Siegman
Subject:	Re: What's PZT
Date:	Mon, 17 Jan 2005 09:56:08 -0800

In article <351f41F4fremoU1@news.dfncis.de>,
Rainer Engelbrecht wrote:

> In non-PM fibers you could use a PZT to apply a pressure perpenicular on
> the axis of the fiber, rather than stretch along the fiber axis. The
> stress induced birefrigence could be used for polarization controll.
> There is a device made by Oz Optics that uses manually applied pressure
> and a rotation stage for polarization controll. Works fine.
>
> In priciple, two mutually otrhogonal PZT a slightly different locations
> should allow to impose an electrically controlable birefrigence and thus
> retardance in two axes to give full polarization controllwithout any
> further mechanical degree of freedom. Or am I missing something?
>
> Do not know if this works fine on PM fibers, because the intrinsic
> birefrigence is rather strong in this fibers.

When thinking about producing small and not too fast mechanical motions
or pressures, consider also magnetic methods.

After University Labs in Berkeley introduced the first really low-cost
lasers in the early 1970s (priced at circa $300 each rather than the
prevailing several thousand dollars and up), it also produced a really
neat and equally inexpensive little scanning FP interferometer with
plastic end plates and the scanning mirror driven by what was in essence
a miniature loudspeaker coil.

One of the advantages of the magnetic vs piezoelectric approach is low
voltage, higher current drive circuitry, perfectly adapted to IC or
semiconductor electronics. Another advantage is wider range of motion.

From:	Sam Goldwasser
Subject:	Re: What's PZT
Date:	17 Jan 2005 19:15:38 -0500

"A. E. Siegman" writes:

> In article <351f41F4fremoU1@news.dfncis.de>,
> Rainer Engelbrecht wrote:
>
> > In non-PM fibers you could use a PZT to apply a pressure perpenicular on
> > the axis of the fiber, rather than stretch along the fiber axis. The
> > stress induced birefrigence could be used for polarization controll.
> > There is a device made by Oz Optics that uses manually applied pressure
> > and a rotation stage for polarization controll. Works fine.
> >
> > In priciple, two mutually otrhogonal PZT a slightly different locations
> > should allow to impose an electrically controlable birefrigence and thus
> > retardance in two axes to give full polarization controllwithout any
> > further mechanical degree of freedom. Or am I missing something?
> >
> > Do not know if this works fine on PM fibers, because the intrinsic
> > birefrigence is rather strong in this fibers.
>
> When thinking about producing small and not too fast mechanical motions
> or pressures, consider also magnetic methods.
>
> After University Labs in Berkeley introduced the first really low-cost
> lasers in the early 1970s (priced at circa $300 each rather than the
> prevailing several thousand dollars and up), it also produced a really
> neat and equally inexpensive little scanning FP interferometer with
> plastic end plates and the scanning mirror driven by what was in essence
> a miniature loudspeaker coil.
>
> One of the advantages of the magnetic vs piezoelectric approach is low
> voltage, higher current drive circuitry, perfectly adapted to IC or
> semiconductor electronics. Another advantage is wider range of motion.

Hmmmm. Well, the SFPIs I've built still use a PZT - though one ripped from
a digital alarm clock - but the rest sounds similar. Only 30 years late. :)
The types of PZTs in beepers and such don't require high voltage to produce
enough excursion for an SFPI.

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

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

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

From:	redbelly
Subject:	Re: What's PZT
Date:	15 Jan 2005 07:18:43 -0800

RPaschotta wrote:

> A PZT is a piezoeletric transducer

More specifically, "PZT" refers to the material, lead (Pb) zirconate
titanate, that most piezoelectrics are made from. A piezoelectric does
not have to be PZT.

Mark

From:	Alvin
Subject:	Re: What's PZT
Date:	17 Jan 2005 18:04:15 -0800

May i know how many voltage is needed for PZT?

thanks,
alvin

From:	Rainer Engelbrecht
Subject:	Re: What's PZT
Date:	Tue, 18 Jan 2005 11:04:27 +0100

Alvin schrieb:
> May i know how many voltage is needed for PZT?

Typically in the order of ... 100V. We have some with 6µm linear travel
at 150 V.

Rainer

From:	Sam Goldwasser
Subject:	Re: What's PZT
Date:	18 Jan 2005 08:25:55 -0500

Rainer Engelbrecht writes:

> Alvin schrieb:
> > May i know how many voltage is needed for PZT?
>
> Typically in the order of ... 100V. We have some with 6µm linear
> travel at 150 V.

The kind in $1.00 piezo beepers are several times more sensitive. For a
scanning Fabry-Perot interferometer, they are easily driven over several
FSRs by a normal function generator or +/-15 V supply op-amp circuit.

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

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

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