BSTJ 50: 1. January 1971: Measured Attenuation and Depolarization of Light Transmitted Along Glass Fibers. (Cohen, L.G.)

8.9 MB·English

Measured Attenuation and Depolarization
of Light Transmitted Along Glass Fibers

Ry L. 6, GOREN

(tana rnd June 4 70)

Tse wecauremarle ay been made om glare fare immoral én index
matin mi. Phe meabatenente sustude sole of polrietion analyses of
The Ugh easing fibre wud. Phe cararter of fe an was dteriined Ip
ning 8/4 ple Gn comuetin will a polar enalyatr fv wens Ce
Capone of poland ad arsed Sigh

‘Phe data slicer that anced bore etbuate ght ch roe dha
imilr plan ld er tapes, Ade purty wih a ulate lana
for won ested from mosuvanent of e abstr of mea tuving
‘is ed. Laght pied alg wea fore was eouseray low dicted
fon ligt propagating along wimaes bd nape.

‘Pe poasb’tyof using gos vere siletoie wove in opal
commusionien systene evel! Rage, The paper devaibrs the Digkt
fir 8998 4) tenperiena popertiee of unl pass Hikers rman
by index mete ail, Tags «laracteristis ave osnpare with shows
1 ail lal fleas ia ie the ling wus lus, To types of
Shvaal meeaurecacus wore tae: Ue attenuation aM the stale of
poleization of the Hight from & fa en

"Measuremens were mde om severe] slse of Sher (28 yam al
433 yon diamcler uneled Rete; AD gv oad 8 am ear dinmeter clad
Abers| =e index of estaccion ofthe vedi urzounditg unelad
fers wan varied to nionate the bite glass by 884, 305, and 1.17
Porceul, Phe clad bere wow strrounéed hy else whose sefvotive
Tntor was 0924 poreon| lower than that f Ue bul meer

Att rs yore mane yy Dail ad Bicone, nef sua,
GALES TEE ETRE A vee ae Eg. Te ator a ere
Gata ites Bass.
24 ERM RET SYAITAT PENAL, JOKHNA TANTRA 187

Figure 1 ihusealey the Lahuralary selup used to make messure-
roate on bees inmereed in oil. The iaput end of tue Ghee was
ily elampad relative io Ue Taser wry while Che oui el Wat
mnmersed ino to eke ight fection, Power output was trasied
‘ith a solar ell which wae laaled wilh & 1000 0 iapesianve Yo eae
AetectorLineaciy. The output Kight power wss maximised by adjusting
the position ef the bar's inpnt ene with a threedimensions! misro-
rmanipalstor.

Several probleme aroee when uneled bese were immersed in ol
inc toy re rob ented, uno fibers are sensitive to surface cane
‘aminstion. "They were elaned with mothy] ecbyl ketone ead then
‘threaded throogh bwin ire suport. A iaek cardboard holding the
supported fiber wae then pee on lop of the eit trough, ‘The input
ond of the fiber wae clamped rigily and fastoned to the nindow of
the oll cough. Dy aiding tho exzabourd eway fm the wincon fae
tupporto? Sher gould be -owered nto th Inmigh widhoutcouching its
walle Tight st fonused ino Ube bee wail ma el seopended in
hiro that the iapul sip eoul? be exsiy located nee it wa sensed

sa sea aaa _

Bf Bap rageoml for tanminon amen a i
men verwes 25

in index aiehing of. Lised supports wene employed eave
Uae the ght eealered fom cho bur was s negligible perton
cf Lie detected lighs nteneiey, Lighe sor: ho né of a Bbes cid nol

ay substantially in power as 4 funtion ef the oumber of support.
fraciveindexof tho bulk material abd oil samples wae measared
wth Abbe teisetometer. However, the rfrctive index of fibrous
losin eam doubi, ‘The following prooedar, Thstrared in ¥ig. 2,
‘rao used Lo make n deat roeasireme. Tae light was focused ink
1228 acu unel fie whee inp wd pt tps Wore suspended ik a.
‘A small seotion of Ler we smmorsed in oil end its outpul abstr
Energy transmitted throug: the Ber appeared. be extol? when the
refractive ide ofthe il lading wus adjust tobe & = O.614 percent
ts than tho index of ue Bulle gles (eno = LOOM st 6328 A). This
‘pparent deviatos fom the bu glase property may have bows eouned
Dyrebe quorching of the gaa ixpoeed Ty the Gbsr deewing process.”

"The charaetr of the Ahers out wae azalyoed hy ving m2 ate
in eanguneton with « polarld analyzer (refer to Pig. Re and b) to
tmeasnve the Stakes paruretere! (Sp Sy» Se» Sof tas ight. Define
Theos Joy Lato be the light pores treveittod through « polaroid
‘cet whem ie ie oriental para! to the eetons @, , © @ and ex
hoow in Fig. 4. Zy said Fy seo suamitted powers when the polarvid
Tellowe & \/L plate which pmduces © phoap differanse of 2 beoreen
oan,

Tour nrewisennts axe necessary to determine SS. 8

("Tho totel power ofthe beam, Swot te pola
‘Phe dagro nf lane polarization wily respect fo gwo aibrary

anthogoral sxe, 8) — 1, — Dy

«oi The degree of pla polaris ith seepect vo wnat of othoge
‘on anes onfnted £045" lative tothe provious bt Sy = Fa

ie

‘The degase of cielar polsiastion, S, = I, ~ Ty

Partially polaris Tight may be split ink Uw parts: one of power
=e co)

ie is polasian and eter of power Sp — S, wih ic unpolarized.
"The polaraedSraction ef light, peat be computed ru:

oe C)

"The charter of Uy swlatzed tretion of Eght- my be express in
2»

ahfZe Armee wed to eens Ve rrave Sols of aed

(erm of the monochronutie elie Fld strnuth, B, relative to the
trthogonal axes 6, and 8:

equation (2) may be simplified by detning ‘he comple polaization
faotor, Q = tary exp [sla — 6) which uniquely deerme the

Vig 4 oben of a pun wy son 2944
sme oontes 7

itis deta ec iroqende “horas he dni
ie 89a eel es hase Tiince ol 2 Bebecce esto

polviration of on enatrornagnatie wore
B= byewp lie! 1 a))ie + Gest.

‘Pee magne and pase of Q ney be exposed in looms of the Stokes

a= LES) ape cow (8)

148

‘To meke s polarisation swam, @ polagsid shoot was rotated.
ie the light to be analeasd. The pelaroid was eouinte on the geared
Thechnisn: in Vig So which waa used co drive w protaion poten
Ger The nagulir yeition of the polroid sheet waa reoorded on tho
Sanis of an # — y recone. Tho Tight she eransmitted through the
Irtvoid was eoleted by a xkerell snd coo the nde of the revonder
iy eoavestion, the dvetion defied by ein Fig. @eomsjonded to
tho optie nai ofthe polorid when the sheet was ajuted for maxinzam,
ight crapstnssios. Carve (3) om Hig, 5 made in linearly polarized
[esc ict, is «profil of tae trnarisad ight power, 7, a6 8 fusion
fF the gl, @, maaan clockwise between e, ant” Lhe polaoid’s

‘Curve (i) in Fig 6 sos win! shen the poacelel followed 3/4
late whieh prodasod « pis difeence a x/2 between e, al eof Fi
2S mu ma syerew ecuew, Jovnsany sacar wrt

Fig Plants cata Ss Hamty pl ue yh Th ppt
ght vey, py we ecg Fama tte cy sgl nee
eet pisces yet eration 9k ere

‘pond 8 uifect itatss of the put ier a nave oe

4. ‘Tho lineaey polarized ihe whion aye incident on the pave became
‘érvalrlypolaizad and the ansount of light transmittd by the polaroid
thest waa the stmne forall riantation, Tae reneiing curves of Fg, 5
torressond to four ditions! 3° pate urontations relive to ey. Tey
‘ae eel cousin ch a flere aiament of Pig. 4. Fo example
the re would Lave to be eulabed 45" eounisrloleise in onler to
free af referenee for the 2/4 plate orientation corresponding to
carve (4). ‘Phe posse power of the Bg, 8 , showed be invaniont
te rotstion of Fig. 4 Tae quality ofthe 3/4 plate wos aasesed by
comparing , computed for the five orientations: (3) through (e)
‘The rasizsum deviation aroce betwen (i) end () and only emounted
to L.82 parent
‘Beveral eorectng ttetore fd to he determined before the Stokes
musumeton oud he encesured abealutely. Twn dillerent solar ele
‘reve enployed. One detactor we used to naceune git trenatted
‘hrongh the poescid Ge, $8, Sy). The osber ws used to maasize
the total power, Se ‘The sensitivity a jinearty of both detators were
compared the tans beam, Ibe tranemisaivty, Tq, = a/Sy = O78,
tho policed shect in il wea measured by comparing the Heh power
taansmitted wes ita optic axis was parallel toe; wit the total pow
ransnssivty ofthe 9/8 plate mei, Tn. = 1/Se = 047, wns
rmousured by eompuring the ight poxer teasumiticd through it with
the totl pover,
igum 4 strates typical mcanaroments ofthe atete of polation
use o08 »

of the partly poarina ight Ieaving sarple Her lengths, Curve 2}
1 Fig 6 offers consecutive messurements for threo dient ond cuts
of the come 10 pm alad Sber which had boon totally immored in el
Te ilustrates that end efoss ure negli fc imerva bers

‘Tie profiles, off vena & appar “or cage raarursment ia Fy. 6
One profi we obtained when the polar folloted a4 plate whi
odced « phase diferenee of 12 botwoen esd es «Th was wed to
‘determine Sy . The otter profile vas ublained without the Af4 plate
snd was used to datersing 8 nad S,. Tho threo guramelers 8, So
tnd &y ware nosuaniaed rbtive tothe toil power, Sy , od were used
tocompute the polarized "wanton a ight, fm equation (1) and (2)
Home wil Ue couples goltiaation Tector, Q, tm equation ().
CCoupasious of Figs Ga aad Ge with Hig, GB iiutrates that the do-
‘ge of sealer polaszation, determined from the mensuramont with

eo

seaman

ade hun Sola Reh SR Se SP

im,
the 4/4 plat, could vary over x wide range. The analy owt on the
poe in Fiz wre nelle is ot Figure. The ale Tigh we
75 peroort polaranl. Tie polzvaod traction wea chavastetzal by
= 105 exp (225°) Such meta should be independent of light power
fand choy were aypnovinaaly a0, Figure 7a ie plok of were nat
alized fap. pow for a Al-om length of 25 ym tiber with a= 241
pereeut, Figine 7h abows @ plowted in the parpiex plane with light
Intensity as Ube parmoter. ‘Thi poi arp mmbers sequal
correspond to pels of Fig. Ta reading from veht to lat. If depolar-
‘ation Val not gecurrd the light would havoboca 100 vaecnt polarized
Ge, p = 1) and all dasa pointe ic the complex @ plans woud have
been foes at 1 | 0%. The mse of Fig. Ta ard Windies tah,
seg. 0,10) deviated by only =b87 porennt, 42.5", £18 poreont frm
thee mean vac when the input power mse doubled

a 2 eh, oF
eM y

Tig Teste of plc as yr uel er cy a= 244038
SESSA SE I EG os ae eee
PERL OL SEDS cede Ue eg ine tale
roe omnes a

Optinal poopertioe of Sbers weve weaned ae a feelin» of Aber
Ter, fi neasined fm the apa lip. The ngch wes hanged by
culling ol? kuowi Geesements of Shor. Some fumes euotin sovera!
fut of dala points, Ras? 2 of ponse conrad to a cifenent Ske.
‘Archos lager power was nel he rata beéxeen rune, i remained
late dusing toe court of ringle eel ef mereuremonts

‘The tension loss elem, g, of wr i Mets’ fom
tho slope ft semirloganizamie pio of dotelur output, Z, vreue 1

Binoe

1 ©
then

o
FFigsre & aul illite tricia anormorerente mage on ta

Effet’ 1pm nnchad Lieve shied hae boss iorised in oi whose
reltactise inex was 244 perce este than the idee of tho sous
ove ah 6828 A, "The daa pote, sbed sequontin ly needing itor
ah: fio eal Us vtsrpend to soltrtatins meaeutenons
Trade or che ease fibers wi ovonded iz Tig 9. Tight power, , was
“cased i toms of the seals ants et + lakes ample. The stan
Shion eooiekait of nled fibers inenmse ncrkedls ard the powe=
Inpnt, 7, devia Sven an exposentisl deveenee ot for L <I,
{Ths behavior was stobsbly else tn Tsanching pamnemous, Tb wes
inqusensentialsnos mseeurenrets rte always made oa lensths Long,
cningh to take tronszivion pnperties solely cependeat upon fher
pucomelers, Oteasicnaly, ask of lineasity wie notee now the end
[Tuba fe, Theos pce inctesace i extention oeeused en,
Tenzlis of fiber which bid usw conlaminatad upon eonteet with
stasty suface, gure Sr ilsiraes tranesision meuewrements mde
fn a 3 yan clad fiber, The daca paints are coded to correspon to
Polarnation meneurements rvorded is Tiz. 10. The discontinuty at
{ince point 7 of Fig, 80s duo oo «grass imporeetion within the eore
fr ab te cone eladeing itsefuce o Uw 3 inl ie

‘Transmission raeasarement results, Zor clad and uneled fibers exe
sommatied im Tele 1 be hse rimstennts made on olnd bots
ferved (9 calibrate the experimental wshaque, They are consistent
a2 es, svar coemiou. sorasin, seesa

wen av

t
i=
i

set nae O Seana ato ane

swith results ereiallyobtsined hy A.P Tyas eat Fiber diameter
{ia}, the index miematah Inswoan ta oare and ite eurcundings (8),
the seymplotie value of the polarize fretion of lighe fo: long length
cof fiber (py), the eharaetertie mumsar 9 the fiber waveguide

s9Saia),

(= 7 enteg = nin =

and she epproximate number of propugutine modes (N) appeer 25
parameters, Lace eocicinta of th el mln etrounding the immered
‘Shere were meat watt epiesl Tasegain mranaring wl howe
Feoultsy include in Twble T, and the analy outlived in Appenvi B
ineste thet the Sraction of « due to exeey propagating, within the
fl wa lene than 8 patent

‘The dita Tate is Tale U iedicala that she aiention eerstant,
Incrones for decreasing ther diameter, 28, and index misma, 3,
bur nemuirs apprasimacely eonatant whoa the preseding parameter