IEC 62496 2 Edition 1 0 201 7 05 INTERNATIONAL STANDARD Optical circuit boards – Basic test and measurement procedures – Part 2 General guidance for definition of measurement conditions for optical ch[.]
Trang 1IEC 62496- 2
Editio 1.0 2 17-0
Opt ical circuit boards – Basic t est and measurement procedures –
Part 2: General guidance for definit ion of measurement condit ions for opt ical
charact erist ics of opt ical circuit boards
Trang 2THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyr ight © 2 17 IEC, Ge e a, Switzer la d
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Trang 3IEC 62496- 2
Edit io 1.0 2 17-0
Opt ical circuit boards – Basic t est and measurement procedures –
Part 2: General guidance for definit ion of measurement condit ions for opt ical
charact erist ics of opt ical circuit boards
Trang 4CONTENTS
FOREWORD 4
INTRODUCTION 6
1 Sco e 7
2 Normative ref eren es 7
3 Terms an definition 7
4 Me s rement def i ition s stem for o tical circ it b ard 9
4.1 General 9
4.2 Me s rement def i ition s stem req irements 9
4.2.1 Ac urac 9
4.2.2 Ac ounta i ty 9
4.2.3 Ef ficien y 10 4.2.4 Con enien e 10 4.2.5 In e en ent 10 4.2 6 Scala le 1
0 4.2.7 Cu tomised req irements 10 4.2.8 Prioritised stru ture 10 4.3 Me s rement def i ition criteria 10 4.3.1 General 10 4.3.2 Source c aracteristic 1
4.3.3 L u c con ition 1
4.3.4 Input coupl n con ition 14 4.3.5 Output coupl n con ition 15 4.3.6 Ca turin con ition 16 4.4 L u c an ca turin p sition 16 4.5 L u c an ca ture direction 17 5 Me s rement identification code 1
9 5.1 General 19 5.2 Me s rement identification code con tru tion 19 5.2.1 General 19 5.2.2 AAA – Source c aracteristic 19 5.2.3 BBB(b1) – L u c con ition 19 5.2.4 CCC – Input coupln con ition 2
5.2.5 DDD – Output coupl n con ition 2
5.2.6 EEE – Ca turin con ition 2
5.3 Exten ed me s rement identification code with c stomisation p rameters 2
5.3.1 General 2
5.3.2 Cu tomisation p rameters with placeholders 2
5.4 Referen e me s rements 21
5.5 Co rdinate ta le AAA – Source c aracteristic 21
5.5.1 Man atory p rameters 21
5.5.2 Cu tomisation p rameters 21
5.6 Co rdinate ta le BBB – L u c con ition 2
5.6.1 Man atory p rameter 2
5.6.2 Cu tomisation p rameters 2
Trang 55.7.1 Man atory p rameters 2
5.7.2 Cu tomisation p rameters 2
5.8 Co rdinate ta le DDD – Output coupl n con ition 2
5.8.1 Man atory p rameters 2
5.8.2 Cu tomisation p rameters 2
5.9 Co rdinate ta le EEE – Ca turin con ition 31
5.9.1 Man atory p rameters 31
5.9.2 Cu tomisation p rameters 31
5.10 Examples of de loyment 3
5.10.1 General 3
5.10.2 MIC-0 2-1 3(4 0)-0 1-0 1-1 2 (integratin sphere device detais in lu in s p l er an model n mb r) 3
5.10.3 MIC-0 2-12 (2 5)-0 3(1.5 , X,X)-0 1-0 2 (integratin sphere device detai s in lu in s p l er an model n mb r) 3
5.10.4 Fast p larisation axis: MIC-0 1-0 2(15 )-0 2(1.5 , 2 , -3 )-0 1-0 4; slow p larisation axis: MIC-0 1-0 2(7 )-0 2(1.5 , 2 , -12 )-0 1-0 4 3
An ex A (informative) State of the art in o tical intercon ect tec nologies 3
A.1 Diversity of o tical intercon ect tec nologies 3
A.2 Fibre-optic circ it laminates 3
A.3 Polymer waveg ides 3
A.4 Planar glas waveg ides 3
A.5 Fre sp ce optic 3
A.6 Target a pl cation 3
Bibl ogra h 3
Fig re 1 – Optical circ it b ard varieties 6
Fig re 2 – Recommen ed test setup for sin le-mode f ibre lau c con ition 13 Fig re 3 – Recommen ed test setup for multimode fibre lau c con ition 13 Fig re 4 – Cros -sectional views of c an el u der test at input 15 Fig re 5 – Cros -sectional views of the c an el u der test at output 16 Fig re 6 – Me s rement setup with col ne r lau c an ca ture direction 17 Fig re 7 – Me s rement setup with orthogonal lau c an ca ture direction 18 Fig re 8 – Me s rement setup with o l q e lau c an ca ture direction 18 Fig re 9 – Me s rement identification code con tru tion 19 Fig re 10 – Referen e me s rements with the same MIC 21
Ta le 1 – Recommen ed modal lau c profi es 12 Ta le 2 – AAA co rdinate ref eren e f or source c aracteristic 2
Ta le 3 – BBB co rdinate ref eren e f or lau c con ition 2
Ta le 4 – CCC co rdinate referen e for input coupl n con ition 2
Ta le 5 – DDD co rdinate referen e for output coupl n con ition 3
Ta le 6 – EEE co rdinate ref eren e f or ca turin con ition 3
Trang 6INTERNATIONAL ELECTROTECHNICAL COMMISSION
_
OPTICAL CIRCUIT BOA RDS –
Part 2: General guidance for definition of measurement conditions f or
optical characteristics of optical circuit boards
1 Th Intern tio al Ele trote h ic l Commis io (IEC) is a worldwid org niz tio for sta d rdiz tio c mprisin
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Ful information on the votin for the a proval of this International Stan ard can b fou d in
the re ort on votin in icated in the a ove ta le
Trang 7A lst of al p rts in the IEC 6 4 6 series, publ s ed u der the general title Optic l circ it
b ards – Basic test a d me sureme t pro ed ures, can b f ou d on the IEC we site
Future stan ard in this series wi car y the new general title as cited a ove Titles of existin
stan ard in this series wi b updated at the time of the next edition
The commite has decided that the contents of this doc ment wi remain u c an ed u ti the
sta i ty date in icated on the IEC we site u der "ht p:/ we store.iec.c " in the data related to
the sp cific doc ment At this date, the doc ment wi b
• reconfirmed,
• with rawn,
• re laced by a revised edition, or
A bi n ual version of this publ cation may b is ued at a later date
IMPORTANT – Th 'colour in ide' logo on the cover pa e of this publ c tion indic te
that it contain colours whic are consid re to be us f ul f or th cor e t
und rsta din of its conte ts Us rs s ould theref ore print this doc me t usin a
colour printer
Trang 8Ban width den ities in modern data commu ication s stems are driven by interconnect
sp ed an s ala le input output (I/O) an wi contin e to in re se over the comin ye rs,
there y severely imp ctin cost an p rorman e in future data commu ication s stems,
brin in in re sed deman s in terms of sig al integrity an p wer con umption
The projected in re se in ca acity, proces in p wer and b n width den ity in f uture
inf ormation commu ication s stems wi ne d to b ad res ed by the migration of emb d ed
o tical intercon ects into s stem en los res In p rtic lar, this would neces itate the
de loyment of o tical circ it b ard tec nologies on some or al key s stem card , s c as the
b c plane, motherb ard an p ripheral circ it b ard
Man varieties of o tical circ it b ard tec nolog exist today, whic dif fer stron ly f rom e c
other in terms of their intrin ic waveg ide tec nolog As s own in Fig re 1, these varieties
in lu e, but are not l mited to: a) f ibre-o tic laminate, b) p lymer waveg ides an c) planar
glas waveg ides An ex A provides a detai ed overview of the state of the art of s c o tical
intercon ect tec nologies
a) Fibre-o tic laminate b) P ly mer waveg ide c) Planar gla s waveg ide
Figure 1 – Optic l circ it board v rietie
One imp rtant prereq isite to the commercial ado tion of o tical circ it b ard is a rel a le
test an me s rement definition s stem that is ag ostic to the typ of waveg ide s stem
u der test an , theref ore, can b a pl ed to diff erent o tical circ it b ard tec nologies as wel
as b in ada ta le to future variants A seriou an common pro lem with the me s rement
of o tical waveg ide s stems has b en lac of pro er definition of the me s rement
con ition for a given test regime, an con eq ently stron in on isten ies en ue in the
res lts of me s rements by dif ferent p rties on the same test sample To date, no
methodolog has b en esta l s ed to en ure that test an me s rement con ition for s c
o tical waveg ide s stems are pro erly identif ied
This doc ment sp cifies a method of ca turin s f ficient information a out the me s rement
con ition for a given o tical circ it b ard to en ure con isten y of me s rement res lts
within an ac e ta le margin
Given the s bstantial variety in pro erties an req irements for dif ferent o tical circ it b ard
typ s, some test en ironments an con ition are more a pro riate than others f or a given
o tical circ it b ard It is, therefore, cru ial that this me s rement identification stan ard
en omp s a comprehen ive ran e of test an me s rement s enarios for al k own typ s of
o tical circ it b ard an their waveg ide s stems, whie also b in s ff i iently ada ta le an
exten a le to ac ommodate future waveg ide tec nologies In ad ition, a degre of
Trang 9OPTICAL CIRCUIT BOA RDS –
Part 2: General guidance for definition of measurement conditions f or
optical characteristics of optical circuit boards
This p rt of IEC 6 4 6 sp cifies a method of def i in the con ition for me s rements of
o tical c aracteristic of o tical circ it b ard The method comprises the u e of code
referen e lo k-up ta les to identify diff erent critical asp cts of the me s rement en ironment
The values extracted f rom the ta les are u ed to con tru t a me s rement identif i ation code,
whic , in itself , ca tures s ff i ient inf ormation a out the me s rement con ition , so as to
en ure con isten y of in e en ently me s red res lts within an ac e ta le margin
Recommen ed me s rement con ition are sp cified to minimise further variation in
in e en ently me s red res lts
The folowin doc ments are refer ed to in the text in s c a way that some or al of their
content con titutes req irements of this doc ment For dated referen es, only the edition
cited a pl es For u dated referen es, the latest edition of the referen ed doc ment (in lu in
an amen ments) a pl es
IEC 613 0-1, Fibre o tic interc n e ting d evic s a d p s ive c mp n nts – Basic test a d
me sureme t pro ed ures – Part 1: Ge eral a d g ida c
IEC 613 0-3-5 , Fibre o tic interc n e t in d evices a d p s iv c mp n nts – Basic test
a d me sureme t pro edures – Part 3-53: Ex amin t ions a d me sureme ts – Encircl ed
a g lar fl ux (EAF) me sureme t method b sed o two-d ime sion l far field d ata fom ste
ind ex multimod e wa e uide (in l ud in fibre)
IEC 6 614, Fibre o t ics – L u c c nd ition re uireme ts for me suring multimod e
Trang 10optic l c a nel me s reme t ide tif ic tion code
MIC
n merical code u ed to ca ture s ff i ient information a out the me s rement con ition on a
waveg ide u der test in an o tical circ it b ard, s c as to en ure in e en ent re e ta i ty
of the me s rement an con isten y of me s red res lts on an identical sample
3.2
optic l c a nel und r te t
o tical circ it b ard c an el s bjected to test an me s rement regime
3.3
parabol c profi e parameter
p rameter whic des rib s the ref ractive in ex prof ile of waveg ide ac ordin to the fol owin
ar
ar
n
rn
g
∆
∆
21
21
)(
11
22
1
2/ nn
stru ture or mec anism whic g ides l g t f rom the me s rement test source to the input
facet of the o tical c an el u der test
Note 1 to e try: Ex mple in lu e o tic l fibre , o tic l wa e uid s or o tic l train
3.5
c pturing conduit
stru ture or mec anism whic g ides l g t f om the output facet of the o tical c an el u der
test to a me s rement device
3.6
top input a is of c a nel u der te t
axis defined by the tester within the plane of the input facet u ed as a referen e, again t
whic the p larisation axis of the lau c con uit can b defined
3.7
top output a is of c a nel und r te t
axis defined by the tester within the plane of the output facet u ed as a ref eren e, again t
whic the p larisation axis of the ca turin con uit can b def i ed
3.8
polaris tion maintaining o tic l fibre
sin le-mode o tical f ibre in whic l ne rly p larized l g t, if pro erly lau c ed into the fibre,
Trang 11p larisation state with l tle or no cros -coupl n of o tical p wer b twe n the two p larisation
modes
Note 1 to e try: Su h fibre is u e in s e ial a plc tio s wh re pre ervin p laris tio is e s ntial a d is
c ara teris d b a f ast a is a d a slow a is
3.9
ref ra tiv inde matc in material
compl ant or fixed material with a ref ractive in ex eq al to the ref active in ex of the core of
the c an el u der test at the me s rement wavelen th an me s rement con ition , whic ,
u les otherwise stated, is the stan ard atmospheric con ition as ac ordin to IEC 613 0-1
3.10
ref ra tiv inde damping material
compl ant or fixed material with a refactive in ex within 0,0 of the refactive in ex of the
core of the c an el u der test at the me s rement wavelen th an me s rement con ition ,
whic , u les otherwise stated, is the stan ard atmospheric con ition as ac ordin to
IEC 613 0-1
4 Measurement def inition system f or optical circuit boards
A relable test an me s rement definition s stem for o tical intercon ect is a cru ial
prereq isite f or future commercial ado tion of o tical circ it b ard tec nology
In e en ent re e ta i ty of waveg ide me s rements is sti very diff i ult to ac ieve d e to
the lac of clarity on how me s rement con ition are sp cif ied
Therefore, s c a definition s stem s al ca ture s f ficient inf ormation a out the
me s rement con ition to en ure that the res lts of me s rement on an identical test
sample by in e en ent p rties wi b con istent within an ac e ta le margin of er or
Given the large n mb r of me s rement p rameter p rmutation p s ible, the amou t of
inf ormation req ired to des rib s ff i iently the me s rement con ition is prohibitive It
would b impractical f or testers to provide a ful textual des ription f or e c typ of
me s rement, esp cial y in situation where o tical circ it b ard are s bjected to a variety
of diff erent me s rement regimes, f or in tan e, as p rt of a comprehen ive q alty as uran e
regime in a commercial o tical circ it b ard fou dry
IEC 6 4 6-2-1 provides detai s on variou typ s of me s rements that can b car ied out on
o tical circ it b ard
4.2 Me s reme t definition s stem re uireme ts
4.2.1 Ac ura y
The me s rement definition s stem s al ca ture s f ficient information to en ure varia i ty in
in e en ently me s red res lts within an ac e ta le margin
4.2.2 Ac ountabi ity
The me s rement def i ition s stem s al force testers to b ac ou ta le to provide s f ficient
information a out the me s rement con ition The s stem s al therefore comprise a
f ormalsed famework to ca ture the req ired amou t of inf ormation a out the me s rement
Trang 124.2.3 Ef ficie c
The me s rement definition s stem s al alow the entirety of the me s rement con ition
information to b a breviated into an o tical c an el me s rement identif i ation code (MIC)
s c that it can b contained within no more than one l ne of text
4.2.4 Conv nie c
The me s rement identif i ation code s ould b e s to con tru t an decon tru t u ing the
ref eren es lo k-up ta les in this doc ment
4.2.5 Ind pe de t
The me s rement definition s stem s al b in e en ent of the typ of o tical circ it b ard
u der test in order to ac ommodate diff erent varieties of o tical intercon ect To this en , the
typ of o tical c an el u der test wi not b in lu ed in the inf ormation to b sp cified; it wi
b tre ted as a "blac b x" b u ded by the input facet an output f acet of the o tical c an el
u der test
4.2.6 Sc lable
The me s rement definition s stem s al b s ala le to ac ommodate new me s rement
con ition a pro riate to existin or as yet u k own o tical intercon ect typ s To this en ,
the s stem wi have placeholders to al ow e s ad ition of new inf ormation in f uture
4.2.7 Cu tomis d re uireme ts
Where the p rameters of a me s rement con ition are not expl citly provided in the
cor esp n in lo k-up ta les, the MIC s al b exten a le to ac ommodate u er def i ed
p rameters
4.2.8 Prioritis d stru ture
The me s rement def i ition s stem s al give pref eren e to me s rement config ration that
are
• ac es ible, favourin the u e of avai a le an af forda le eq ipment,
• via le, f avourin me s rements whic can b e si y car ied out by most organisation
without the req irement for sp cial sed or restricted eq ipment or exp rtise, an
• u eful, favourin me s rement of o tical c an el c aracteristic , whic are most common
an relevant to its de loyment an o eration, for example in ertion los
4.3 Me s reme t definition criteria
The me s rement def i ition s stem s al provide information on the fol owin five critical
asp cts of the me s rement en ironment:
• source c aracteristic (4.3.2);
• lau c con ition (4.3.3);
• input coupl n con ition (4.3.4);
• output coupl n con ition (4.3.5);
Trang 134.3.2 Sourc c ara teristic
Typical sources f or common me s rements on o tical circ it b ard c an els in lu e LEDs,
laser diodes an white l g t sources, whi e les common sources in lu e ampl fied
sp ntane u emis ion devices In order to ac ommodate a comprehen ive ran e of avaia le
source typ s and c aracteristic , the me s rement identif i ation s stem wi def i e most
sources in terms of p rmutation of key pro erties in lu in wavelen th an sp ctral width
Source o tical p wer or modal profi e ne d not b sp cified as only the o tical p wer, an
modal profi e at the lau c f acet ne d b sp cified as p rt of the lau c con ition Ta le 1 in
IEC 6 4 6-2-1:2 1 provides a l st of recommen ed source c aracteristic
4.3.2.2 Modulate sourc s
Ac ordin to this doc ment, the source ampl tu e an phase is con idered u -mod lated
Optical mod lation is a large an complex are with many p s ible p rmutation of
mod lation typ , d ty c cle an data c aracteristic Mod lation s hemes in lu e stan ard
on-of f keyin (OOK) an multi-level mod lation s hemes s c as phase ampltu e mod lation
(PAM), in-phase an q aternary (IQ) mod lation s hemes s c as q adrature phase s if t
keyin (QPSK), multi-level q adrature ampl tu e mod lation (nQAM), multi-pulse mod lation
s hemes, an dis rete multi-tone (DMT) Data c aracteristic would in lu e pseu o ran om
binary seq en e (PRBS) data with variou cor elation len th , as wel as test data as ociated
with re l data tran mis ion protocols Mod lation wi not b in lu ed in the me s rement
definition s stem des rib d in this doc ment In the event of a mod lated source, the
mod lation c aracteristic s al b stated expl citly
4.3.2.3 Wa ele gth division multiple e sourc s
Ac ordin to this doc ment, the source is con idered to b centred on a sin le wavelen th
with varyin sp ctral width , or white, whic is con istent with the u e of common commercial
sources in lu in laser diodes, LEDs or ampl f ied sp ntane u emis ion devices It may b
desira le to c aracterise the p rf orman e of the c an el u der test with wavelen th division
multiplexed (WDM) l g t in whic multiple wavelen th are s p rp sed onto the lau c
con uit in ac ordan e with variou WDM s hemes For example, the co rse wavelen th
division multiplexin (CWDM) s heme al ows on the order of ten sig als to b en oded onto
se arate wavelen th The den e wavelen th division multiplexin (DWDM) s heme al ows
on the order of h n red of sig als to b en oded onto se arate, more closely sp ced,
wavelen th
WDM sources are not in lu ed in this doc ment, as the p s ible p rmutation would b
prohibitively complex In the event of a wavelen th division multiplexed source, the
wavelen th division multiplexing c aracteristic s al b explcitly stated Prefera ly, if
con enient, e c wavelen th-en oded c an el can b u iq ely sp cif ied u in the
me s rement identification s stem outl ned in this doc ment
4.3.3 La nc condition
L u c con ition have the gre test ef fect on varia i ty of me s rement res lts on o tical
circ it b ard c an els It is, therefore, cru ial that these b s ff i iently defined
L u c con ition s al in lu e the f ol owin information that determines how l g t pro agates
throu h the o tical c an el u der test an , therefore, determines the in e en ent
re rod cibi ty of the me s rement:
a) lau c facet size an s a e, whic is typical y def i ed by the core of the lau c con uit –
f or a stan ard fibre, it would b s f ficient to sp cify the f ibre typ ;
Trang 14c) sp tial (ne r f ield) an an ular (far field) o tical p wer distribution of l g t at the lau c
facet The lau c con ition f or multimode fibres s ould pref era ly comply with en ircled
flu (EF) req irements defined in IEC 613 0-1 or en ircled an ular flu (EAF)
req irements def i ed in IEC 613 0-3-5 Su h lau c con ition can b rel a ly ac ieved
by de loyin a pro riate mode fi terin eq ipment arou d or in-l ne with the lau c
con uit The lau c con ition for sin le-mode fibres s ould comply with IEC 613 0-1
4.3.3.2 Re omme d d la nc conditions
Ta le 1 def i es key recommen ed lau c profi es, in lu in u deri ed prof iles, variou mode
f iltered multimode profies an overi ed prof iles, as wel as recommen ation on how to
re rod ce some of these modal prof iles
Th s urc is p s e into a 5 mgra e in e multimo e fibre
(GI-MMF), whic is wra p d 2 time aro n a 3 mm diameter
ma drel Th o tp t of th ma drel is th n p s e thro g a
mo e c ntroler/fiter pro u in a mo e fitere o tic l inte sity
pro le, whic c mple with E re uireme t of IEC 612 0-4-
This is th n u e a th in ut to a 5 m GI-MMF, whic is
wra p d 2 time aro n a 3 mm diameter ma drelto
pro u e a mo e-strip e o tic l inte sity pro le at th GI-MMF
5 m gra e in e multimo e fibre (GI-MMF) is p s e thro g
a mo e c ntroler/fiter pro u in a mo e fitere o tic l
inte sity profie at th GI-MMF la n h fa et, whic c mple
with E re uireme t of IEC 612 0-4-
L
a)
EMD
Eq i brium mo al distrib tio
5 m 5 µm gra e in e OM3 multimo e fibre (GI-MMF) is
wra p d 2 time aro n a 3 mm diameter ma drel to
pro u e a mo e-strip e o tic l inte sity profie at th GI-MMF
la n h fa et
L
a)
OF
Ov ri e distrib tio – u iform
n arf i ld o tic l inte sity
distrib tio
5 m 10 µmste in e multimo e f i re (SI-MMF) is wra p d 2
time aro n a 3 mm diameter ma drel to cre te a mo e
-s ramble , o eri e o tic l inte sity profie at th SI-MMF
5 m 2 0 mc re ste -in e fibre (SI-MMF) is p s e thro g a
mo e c ntroler pro u in a mo e f iltere o tic l inte sity
pro le at th la n h f ac t, whic c mple with th EAF
re uireme t of IEC 613 0-3-5
a)
Be d in e sitiv fibre is n t re omme d d for MM or SM te t le d
4.3.3.3 Re omme de sin le-mode fibre la nc me s reme t s tup
The recommen ed me s rement setup for sin le-mode f ibre lau c con ition is s own in
Fig re 2 A sin le-mode o tical source s ould b con ected with a sin le-mode o tical fibre,
f irst throug a sin le-mode o tical isolator to s ield the source fom u wanted b c
-reflection oc ur in at diff erent interf aces f urther on down the test l n , esp cial y the
interf ace b twe n the lau c facet an the input f acet of the c an el u der test The output
f om the o tical isolator s ould then b con ected throu h a varia le sin le-mode o tical
Trang 15the req ired o tical p wer as defined in the me s rement identification code This can
alternatively b ac ieved by u in a p wer tu e ble source
Figure 2 – Re omme de te t s tup for single-mod fibre la nc con itions
4.3.3.4 Re omme de multimod fibre la n h me s reme t s tup
A sin le-mode or multimode o tical source s ould b connected with a sin le-mode or
multimode o tical fibre, first throu h a sin le-mode or multimode o tical isolator to s ield the
source f rom u wanted b c - eflection oc ur in at dif ferent interf aces f urther on in the test
l n , esp cial y the interf ace b twe n the lau c facet an the input f acet of the c an el
u der test If the source is a coherent source, it wi b imp rtant to u e a sp c le fiter to
average out the ef fects of sp c le at the lau c facet One device can b an
electromec anical s aker a pled af ter the source but b fore the varia le o tical at en ator If
u in s c a device, it is imp rtant that the fibre b completely mec anical y decoupled fom
the lau c f acet, so the device s ould b a pled b twe n the source an the varia le o tical
at en ator The photodetector u ed to me s re the received l g t would ne d to b config red
to record average values over an a pro riate time p riod, rather than immediate values The
output fom the o tical isolator s ould then b con ected with sin le-mode or multimode f ibre
to the input of a varia le sin le-mode or multimode o tical at en ator This wi alow the
tester to adju t the o tical p wer at the lau c facet to matc the req ired o tical p wer as
defined in the me s rement identif i ation code Alternatively, this can b ac ieved by u in a
p wer tu e ble source Then the output of the varia le o tical at en ator wi b con ected
with multimode f ibre to the input of a modal con itionin or fiterin s stem, the output of
whic wi b con ected with multimode f ibre to the lau c facet The purp se of the modal
con itionin or fi terin s stem is to en ure that the modal profi e of the lau c f acet is
defined ac ordin to L , L , L , L or L in Ta le 1 Fig re 3 s ows the recommen ed test
setup
L is the prefer ed lau c con ition, in whic a modal profi e is generated, whic compl es
with the restricted lau c EF req irements of IEC 613 0-1, an this in turn is injected into a
GI-MMF f ibre man rel to prod ce a normal sed output
Trang 164.3.4 Input coupl ng conditions
Input coupl n con ition provide information on how the lau c con uit is con ected to the
input facet of the o tical c an el u der test, f or example throu h but-coupl n or imagin
throu h a len s stem, an whether or not the input facet is tre ted with ref active in ex
matc in or dampin materials to mitigate s at erin los es
4.3.4.2 Compl a t a d fix d refra tiv inde matc in material or refra tiv inde
damping material
It is common practice to a ply a ref ractive in ex matc in or dampin material to the input
an /or output f acet of the c an el u der test in order to mitigate Fres el ref lection an
s at erin ef fects cau ed by the rou h es of the input an /or output facet s r ace The
refactive in ex material can b in the f orm of a l q id or gel, whic wi provide a compl ant
buff er, an is b st s ited to me s rement where y the lau c f acet is but-coupled in direct
contact or within a few micron of the input facet, s c that the l q id or gel completely fi s
the ga b twe n the lau c facet an the input facet of the c an el u der test The u e of
l q id or gel would not b s ita le in the case of a f e sp ce projection of l g t onto the input
f acet of the c an el u der test (s c as imagin of the output of a fibre facet onto the input
f acet of the c an el u der test u in a len as embly), as the s r ace ten ion of the
compl ant material would cau e it to f orm a b u dary of u predicta le ge metry arou d the
input f acet of the c an el u der test The alternative to u in a complant ref ractive in ex
matc in material or ref active in ex dampin material is to u e a f i ed ref ractive in ex
matc in or dampin material with a defined flat s r ace, s c as a thin fim This is u eful
when the input facet of the c an el u der test has hig rou h es , but a f e sp ce lau c is
u ed
4.3.4.3 Polaris tion depe de t input coupl ng conditions
One imp rtant p s ible me s rement p rameter f or sin le-mode lau c con ition is the f ast
or slow p larisation axis of the lau c facet relative to the c an el u der test For example,
this would b req ired to c aracterise the p larisation de en ent los or the birefin en e of
the c an el u der test For this purp se, a to axis of the input c an el u der test s al b
defined by the first tester or test sample cre tor an cle rly marked on the sample containin
the one or more c an els u der test or otherwise des rib d in ac omp n in l terature
In me s rements req irin a defined p larisation, the sin le-mode fibre could b a
p larisation maintainin o tical fibre as defined in IEC TR 6 3 9 The o tical p wer exitin a
p larisation maintainin o tical fibre wi b divided b twe n the fast axis an the orthogonal
slow axis The ratio of o tical p wer contained in the f ast axis to the o tical p wer contained
in the slow axis de en s on a n mb r of con ition , in lu in how the p wer was lau c ed
into fibre
In the event that a p larisation maintainin o tical fibre or other sp cial ty fibre is u ed in
whic the o tical p wer contained in the two orthogonal p larisation axes of the lau c facet
is a req ired me s rement p rameter, the me s rement wi b defined u in two in tan es
of the me s rement identification s stem outl ned in this doc ment In this way, a sin le
me s rement wi b tre ted as two se arate me s rements, e c definin one of the
p larisation on its own
Fig re 4 s ows that the to axis of the c an el u der test an the c osen p larisation axis of
the lau c f acet of a p larisation maintainin o tical fibre wi form a relative an le c3 in u its
of degre s This an le wi b def i ed as p rt of the me s rement identification s stem
Trang 174 a) Cros -s ctio al f ro t view of the in ut fa et of the chan el u der te t
4 b) Cros -s ctio al ba k view of lau ch co d it
4 c) Cros -s ctio al f ro t view of chan el u der te t with lau ch fa et alg ed o er it
NOT 1 In Fig re 4 a), th to in ut a is is s own
NOT 2 In Fig re 4 b), th c o e p laris tio a is of th la n h f ac t is in lu e
NOT 3 In Fig re 4 c), th to a is of th c a n l u d r te t forms a a gle c in d gre s with th c o e
p laris tio a is of th la n h f ac t
Fig re 4 – Cros -s ctional views of c a nel under te t at input
4.3.5 Output coupl ng conditions
Output coupl n con ition provide information on how the l g t is coupled out of the output
facet of the o tical c an el u der test to the ca turin con uit, for example throu h but
-coupl n or imagin throu h a len s stem, an whether or not the output f acet is tre ted with
refactive in ex matc in or dampin materials to mitigate s at erin los es
One imp rtant p s ible me s rement p rameter for sin le-mode ca turin con ition is the
p larisation axis of the ca turin facet relative to the to axis of the output facet of the
c an el u der test For this purp se, a to axis of the output c an el u der test s al b
defined by the first tester or test sample cre tor an cle rly marked on the sample containin
the one or more c an els u der test or otherwise des rib d in ac omp n in l terature In
me s rements req irin a def i ed p larisation, the sin le-mode fibre s ould b a p larisation
maintainin o tical f ibre as def i ed in IEC TR 6 3 9 Fig re 5 s ows that the to axis of the
output facet of the c an el u der test an the c osen p larisation axis of the ca turin facet
of a p larisation maintainin o tical f ibre wi form a relative an le d3 in u its of degre s This
an le wi b defined as p rt of the me s rement identification s stem outlned in this
doc ment As viewed facin the output f acet of the c an el u der test, movin anticloc wise
f om the to axis, the an le in re ses p sitively for the entire revolution
Trang 185 a) Cros -s ctio al f ro t view of he o tp t f ac t of he chan el u der te t
5 b) Cros -s ctio al ba k view of he c pturin co d it
5 c) Cros -s ctio al f ro t view of the o tp t f ac t of chan el u der te t
with the c pturin fa et alg ed o er it
NOT 1 In Fig re 5 a), th to o tp t a is of c a n l u d r te t is s own
NOT 2 In Fig re 5 b), th c o e p laris tio a is of th c pturin fa et is in lu e
NOT 3 In Fig re 5 c), th to a is of th o tp t c a n l u d r te t forms a a gle d in d gre s with th c o e
p laris tio a is of th c pturin f ac t
Fig re 5 – Cros -s ctional views of the c a nel under te t at output
4.3.6 Capturin con itions
The ca turin con ition in lu e information on the ca turin con uit u ed to extract the
o tical sig al f rom the o tical c an el u der test an b sic inf ormation on the me s rin
element, s c as a photodetector or CCD camera However, it s al b noted that, al other
con ition b in eq al, the resp n e of the me s rement eq ipment itself wi vary fom
device to device, so it is a req irement of this doc ment that the me s rement eq ipment b
sp cified explcitly as wel
4.4 La nc a d c pturing position
The p sition of the lau c f acet relative to the input facet of the c an el u der test an the
p sition of the ca turin f acet relative to the output f acet of the c an el u der test are critical
p rameters In waveg ide me s rements, the stan ard proced re is to adju t the lau c an
ca turin axes arou d the input an output f acets of a c an el u der test resp ctively to
ac ieve the maximum tran mitan e or minimum in ertion los The resp ctive p sition of
lau c an ca turin axes relative to the input an output f acets of the c an el u der test
req ired to ac ieve maximum tran mit an e de en stron ly on the ge metry of the c an el
u der test an rarely coin ide with the exact centre of the input an output f acets In e d, it
would b prohibitively diff i ult f or testers to identify the exact centre of the input an output
facets an al g the centres of their lau c an ca turin facets to them
The most via le an re e ta le me s rement is, theref ore, the maximum tran mit an e
ac ieva le on a given c annel u der test This as umes comp ten es of the testers to adju t
pro erly their lau c an ca turin devices to identify this, but this is the most re rod cible
Trang 194.5 La nc a d c pture dire tion
The input facet of the o tical c an el u der test is defined as the are throu h whic the lg t
ne d to b injected in order to b b st con eyed into the o tical c an el u der test The
output f acet of the o tical c an el u der test is def i ed as the are throug whic l g t exits
the o tical c an el un er test
In most o tical waveg ide c an els, the input an output f acets of the c an el u der test are
orthogonal to the axis of the c an el u der test, as s own in Fig re 6 If the input facet of the
c an el u der test is orthogonal to the axis of the c an el u der test, the axis of the lau c
con uit s al b col ne r with the axis of the c an el u der test when car yin out the
fu damental me s rement If the output facet of the c an el u der test is orthogonal to the
axis of the c an el u der test, then the axis of the ca turin con uit s al b col ne r with the
axis of the c an el u der test when car yin out the fu damental me s rement
Fig re 6 – Me s reme t s tup with col ine r la nc a d c pture dire tion
In some o tical waveg ide c an els, a deflection element or stru ture that deflects the l g t
pro agatin alon the main waveg ide axis by 9 ° can b in orp rated In s c cases, the
input an /or output facets of the c an el u der test can b p ral el to the axis of the c an el
u der test, as s own in Fig re 7
If the input f acet of the c an el u der test is p ral el to the axis of the c an el u der test, the
axis of the lau c con uit s al b orthogonal to the axis of the c an el u der test when
car yin out the fu damental me s rement of minimum in ertion los If the output f acet of
the c an el u der test is orthogonal to the axis of the c an el u der test, the axis of the
ca turin con uit s al b orthogonal to the axis of the c an el u der test when car yin out
the fu damental me s rement of minimum in ertion los
IE C
So rc
Dete tor
Trang 20Figure 7 – Me s reme t s tup with orthogonal la nc a d c pture dire tion
There may b other cases in whic the axis of the lau c con uit an the ca turin con uit
are not normal to the input an output f acet For example, Fig re 8 s ows a waveg ide with a
s rf ace gratin coupln stru ture o timised to def lect l g t out of the waveg ide at an o l q e
an le, althou h the input facet an output facet are p ral el to the waveg ide axis
Trang 21It is un ersto d in this doc ment that the lau c con uit an ca turin con uit wi b
oriented as req ired relative to the input an output facets of the o tical c an el u der test to
al ow the fu damental me s rement Therefore, there is no restriction on the direction of the
lau c an ca turin con uit relative to the input f acet an output facet of the c an el u der
test
5 Measurement identif ication code
The me s rement def i ition s stem req ires the u e a me s rement identification code (MIC)
to sp cify s ff i iently the me s rement con ition for the o tical c an el un er test (Fig re 9)
NOT 1 Ma d tory p rameters are in b ld te t
NOT 2 Cu tomis tio p rameters are in italc
Fig re 9 – Me s reme t ide tif ic tion code construction
5.2 Me s reme t ide tif ic tion code construction
5.2.1 Ge eral
The MIC is comprised of five thre -digit n merical co rdinates that re resent the f i e critical
are s of the me s rement environment, as des rib d a ove Eac co rdinate is also f ol owed
by a set of c stomisation p rameters in p rentheses relatin to that co rdinate
5.2.2 AAA – Sourc c ara teristic
Co rdinate AAA contain the inf ormation a out the source u ed to stimulate the o tical
c an el The co rdinate value is o tained fom the first referen e lo k-up ta le (Ta le 2)
5.2.3 BBB(b1) – La nc condition
Co rdinate BBB contain information a out the con uit u ed b twe n the l g t f rom the
source an the input p int of the o tical c an el u der test The co rdinate value is o tained
f rom the secon ref eren e lo k-up ta le (Ta le 3) The BBB co rdinate s al b fol owed by
the value of the total average o tical p wer as me s red at the lau c f acet expres ed in
u its of microwat s This is man atory
IE C
MIC A A(a , a2) – B B(b1,b2, b3, b4) – C C(c , c2, c3) – D D(d1, d 2, d ) – E E(e , e2, e3, e )
Trang 225.2.4 CCC – Input coupl ng conditions
Co rdinate CCC contain information a out how l g t is coupled f om the lau c con uit to
the input p int of the o tical c an el u der test The co rdinate value is o tained f rom the
third ref eren e lo k-up ta le (Ta le 4)
5.2.5 DDD – Output coupl ng condition
Co rdinate DDD contain inf ormation a out how l g t is coupled out of the output facet of the
o tical c an el u der test to the ca turin con uit or element The co rdinate value is
o tained f om the f ourth referen e lo k-up ta le (Ta le 5)
5.2.6 EEE – Capturing conditions
Co rdinate EEE contain information a out the ca turin con uit (if any) b twe n the output
f acet an the o tical me s rement device The co rdinate value is o tained f rom the f if th
ref eren e lo k-up ta le (Ta le 6)
The n merical value of e c co rdinate wi b extracted f om the cor esp n in co rdinate
ref eren e ta les in the f ol owin s bclau es
5.3 Exte de me s reme t ide tif ic tion code with c stomis tion parameters
The MIC can b exten ed, if neces ary, to ac ommodate sp cific c stomisation p rameters
for u er def i a le me s rement c aracteristic
In this case, the c stomisation p rameters are in lu ed in brac ets immediately after the
3-digit co rdinate value to whic it a pl es The c stomisation p rameters are def i ed f or e c
co rdinate ref eren e ta le
The ful MIC with al c stomisation p rameters is defined as fol ows:
MIC AAA(a1, a ) – BBB(b1, b , b , b ) – CCC(c1, c2, c3) – DDD(d1, d2, d3) – EEE(e1, e ,
e , e )
For certain co rdinate values, c stomisation p rameters s al b sp cif ied
Cu tomisation ad s complexity to the me s rement definition s stem, p tential y in re ses
me s rement u certainty, an s ould b avoided
The BBB c stomisation p rameter b1, however, s al alway b sp cified
Pref era ly, the me s rement con ition c osen in most cases wi b f om a smal set of
common test setups an wi not req ire c stomisation
5.3.2 Customis tion parameters with pla e olders
In most cases, for a given co rdinate value (e.g CCC), only some of al p s ible
c stomisation p rameters wi b req ired, with others not a pl ca le If an c stomisation
p rameters are sp cified f or a given co rdinate value, ina pl ca le c stomisation p rameters
s ould have an "X" value in the cor esp n in p sition to serve as a placeholder The only
ex e tion is b1, whic is a man atory p rameter, so if there are no values req ired for b , b
or b4, only the b1 p rameter ne d b s own after the BBB co rdinate value