elliptical forallothervaluesof 90 of are difference phase components field electric two fixed the of amplitudes a the and degrees, has light polarized Circularly difference elliptically of values the by groups three into classified be may light Polarized system; reference field; electric the where be expressed: can vector polarization the location, any at t time at components vector Let proportional tothemeansquareofelectricfieldamplitude. electric The to consistofpartiallypolarizedorfullylight. beam light unpolarized. of direction example, the around propagation, randomly fluctuates Light function oftime. a as vector field electric the by plane transverse the in out traced wave's optical the visualizing when field electric the we just field, sketch usually electric the to perpendicular always is field magnetic and field an electric oscillating an which in wave electromagnetic waves. vector of types all to common is that property a is Polarization components. 1(b) of difference phase relative a with components field function Figure directions, y and x the in respectively. Thephasedifferenceis field electric the of phases the are δ oscillating
the over time.(a)withaphasedifference,(b)nodifference. Fig.
, z polarization
there
is Ex E be
is
x x oscillations. 1
same 1
field In
called of
in , Spatial and
the
shows most
between
polarized classical and is time. the In
vector.
E so (ie. magnetic no direction
y
any
natural x-y representation Ey
What isPolarization? are the amplitudes of the x and y components of naturally
that,
e Figure phase δ electric of
x
: other plane. , the
= Polarization
e Its light. physics, linearly a
is the angular frequency; and frequency; angular the is y 90°
on are the unit vectors of the x-y orthogonal x-y the of vectors unit the are or
x light field optical of difference 1(a)
case,
General Photonics Corporation 909.590.5473 and and By produced average, unpolarized
Linearly field propagation.
of
propagate superposition polarized,
beam shows Ex y δ light x- the power
, Ex,andEy. is electric vectors and = defined
light
Ey
between polarized no is
can δ light y- the
is
= if ). modeled electric
direction through
beam circularly
δ
field its a The
be two in Then, x - (sunlight, in scalar of
plane the
represented terms
the δ polarization light components the orthogonal field y . can
space.
the as x-y two is
x- quantity
components of be polarized has
of
favored. a
and polarization
firelight) δ plane
polarization orthogonal the considered δ .
sinusoidal Since no x and x In
y-vector
state electric
pattern that by ( Figure phase
δ
as
=0).
and For the
its δ
is is is y a polarization. linear vertical designates V point opposite diametrically the chosen and arbitrarily An sphere states. the point on polarization points other elliptical All represent polarizations. linear equator the indicate on Points light. polarized circularly unique right-hand a and to corresponds state point polarization given Any form. polarization the change will retarder given any how predicting of It wave. electromagnetic propagating a of polarization in changes The Poincaré SphereandStokesVectors DOP canalsobeexpressedas: partially polarizedlight. DOP=1, Whenever with avaluebetween0and1. The degreeofpolarization(DOP)isdefinedby: which arethecoordinatesofonepointonPoincarésphere. If hand circularlypolarizedlightintensities. and intensities, light polarized linearly intensities, light polarized linearly where propagation oflight),theStokesvectorcanbeexpressedas: In physical interpretationrelatedtointensitymeasurement. related The
we provides a
Poincaré Stokes
given on normalize H Fig. 2Poincarésphererepresentationofpolarizationstates I
0
to on is the total power of the light, the of power total the is it www.generalphotonics.com the
DOP=0,
is Poincaré a Oxyz
the
parameters sphere. totally convenient
sphere
equator [ S
1 reference S light
polarized. 2 The sphere
is S
designates
3 is
way used ] by ] have two said
system representation. of
S
poles
Intermediate to a 0 to ,
representing
simple we describe
I be +45 horizontal
of (Oz will I unpolarized, ,
L the I ,
-45 -45
I I physical being R get x are the left and right and left the are
,
sphere are the cases I y
polarized the are the x- and y- y- and x- the are They linear
the polarization the
SOP
represent correspond
and interpretation
45° also direction polarization, [
s whenever light, and 1
s have 2
s -93- -45° left- and and
3
of to ], a
FAQS Applictia on Guide Accessories Special Polaritizaon OCT Products Modules INSTRUMENTSINSTRUMENTS Components INSTRUMENTS Special Polaritizaon FAQS Applictia on Guide Accessories Components OCT Products Modules INSTRUMENTS -94- while time, over constant fairly are fiber the of asymmetries a be may it or process, manufacturing the from fiber the in inherent out-of-round, or oval slightly and is core fiber the where strand, fiber-optic the of asymmetry the are birefringence the of causes directly slightly at travel fiber a inside light of components polarization different PMD What isPMD? slightly differenttimes,andthestateofpolarizationchanges. at fiber the exit parts two the the because broadened becomes pulse Consequently, speeds. different at travel pulse the of parts other the along principal transmits pulse the of the part of and one axes, along principal transmits pulse was the of it part then which in polarization, polarization of state launched. same the and in fiber the through emerges transmits pulse the fiber’s then the of axes, either principal with aligned polarization its with material If relative a experience phase differenceastheypropagatethroughthematerial. will axes two light the a of along components projected signal polarization two the result, a As axis. through principal other the in light plane-polarized than faster medium travels the axis principal one into launched light polarized transmits Therefore, Birefringence isalsocalleddoublerefraction. (n refraction, Usually, the of properties transmission medium. the express to axes called axes principal orthogonal special two use may One different. are directions different along polarized light of speeds transmission If refraction ofthemedium. of index the is n and vacuum, a in light of speed the is c where be expressedas: same In What isBirefringence? light, respectively. where
result e an the ). a
mechanical
homogenous The optical stands
speed I pol light
different of
by
, this axis. However, difference through such I the mechanical
unp
the pulse regardless is
for
are the intensity of polarized light and unpolarized and light polarized of intensity the are can index Because
as
propagating stresses birefringence speeds, polarization
a is or the
be if medium.
of between
launched
isotropic we ordinary stress expressed
refraction of of
launch as General Photonics Corporation 909.590.5473 on
polarization the shown
ν
on the =c/n If mode
n
in into medium's index medium, of 0
a and n and the
the
an fiber. is medium through the a
in pulse
a dispersion. deployed fiber (n anisotropic
measure Figure
optical e 0 state. is called birefringence. birefringence. called is )
The light
and with birefringence, made
is
different asymmetry
This 3. birefringent, extraordinary
fiber. propagates randomly fiber. of
of It PMD
how medium, speed, a occurs The
birefringent The indices is fast
oriented inherent the may
caused
ν plane- at major when index , can can ,
light
two
the
the be of PMD iscalleddifferentialgroupdelay(DGD). fiber mechanical stressduetomovementortemperaturechangeofthe is about3.2timestheaverageDGDofafiber. Figure any values in fixed Because terms
two polarizationcomponentstravelwithdifferentspeeds. the because broadens pulse optical An an and birefringence. axis, effective fast and slow a having plate retardation single a orientations Fig. particular
can value 3. over 3 www.generalphotonics.com of of As vary, A
its for time. real average an
time
dynamic Fig. 4MaxwelliandistributionofDGDS resulting and a fiber approximation,
The given
birefringences follows DGD, is probability
like properties, section in
and many a the dynamic
a
the Maxwellian of
retardation of fiber in
fiber. PMD maximum a series. DGD
has aspect
does Rather,
with plates a distribution It
distribution instantaneous is to not a
equivalent
with PMD. certain it have
is different
described 1st shown a value of
single, to order DGD DGD
at in