6 Procedure a Nominal output signalpo we r: The nominal output sig al p wer is given by the minimum output sig al o tical p wer, for an input sig al o tical p wer sp cified in the releva
Trang 1Optical ampl fier s – T est methods –
Ampl ficateurs optiques – Méthodes d'essai –
Partie 1-3: Par amètres de puissance et de gain – Méthode par apparei de
Trang 2THIS PUBLICA TION IS COPYRIGHT PROTECTED
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Trang 3Optical ampl fier s – Test methods –
Part 1-3: Power and gain parameters – Optical power meter method
Ampl ficateurs optiques – Méthodes d'es ai –
Partie 1-3: Par amètres de puissance et de gain – Méthode par apparei de
INT ERNAT IONAL
ELECT ROT ECHNICAL
ELECT ROT ECHNIQUE
INT ERNAT IONALE
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Trang 4FOREWORD 3
1 Sco e 5
2 Normative referen es 5
3 Terms, definition an a breviation 5
3.1 Terms an definition 5
3.2 Ab reviation 6
4 Ap aratu 6
5 Test sample 9
6 Proced re 9
7 Calc lation 12 8 Test res lts 13 An ex A (informative) Optimization of o tical b n p s fi ter sp ctral width 15 Biblogra h 16 Fig re 1 – Typical ar an ement of o tical p wer meter test a p ratu for me s rement 7
Trang 5INTERNATIONAL ELECTROTECHNICAL COMMISSION
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International Stan ard IEC 612 0-1-3 has b en pre ared by s bcommite 8 C: Fibre o tic
s stems an active devices, of IEC tec nical commit e 8 : Fibre o tic
This third edition can els an re laces the secon edition publ s ed in 2 0 This edition
con titutes a tec nical revision
This edition in lu es the fol owin sig ificant tec nical c an es with resp ct to the previou
Trang 6The text of this stan ard is b sed on the fol owin doc ments:
Ful information on the votin for the a proval of this stan ard can b foun in the re ort on
votin in icated in the a ove ta le
This publ cation has b en draf ed in ac ordan e with the ISO/IEC Directives, Part 2
A lst of al p rts in the IEC 612 0 series, publ s ed u der the general title Op ticalamplfie rs –
Te st meth ds
1)
can b fou d on the IEC we site
This International Stan ard is to b u ed in conju ction with IEC-612 0-1
The commit e has decided that the contents of this publ cation 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 publ cation At this date, the publ cation wi b
Th first e itio s of s me of th s p rts were p bls e u d r th g n ral title O ptcal fibre am plfiers – B asic
sp ecificato or Optc l am plfier test meth ds
Trang 7OPTICAL AMPLIFIERS – TEST METHODS –
Part 1-3: Power and gain parameters –
Optical power meter method
This p rt of IEC 612 0-1 a pl es to al commercial y avai a le o tical ampl fiers (OA) an
o tical y ampl fied s bs stems It a pl es to OA u in o tical y pumped fibres (OFA b sed on
either rare-e rth do ed fibres or on the Raman efect , semicon u tors (SOA), an
waveg ides (POWA)
NOT Th a plc bi ty of th te t meth d d s rib d in th pre e t sta d rd to distrib te Rama amplfiers is
for furth r stu y
The o ject of this p rt of IEC 612 0-1 is to esta l s u iform req irements for ac urate an
rela le me s rements, by me n of the o tical p wer meter test method, of the fol owin OA
p rameters, as defined in IEC 612 1-1:
a) nominal output sig al p wer;
b) gain;
c) p larization-de en ent gain;
d) maximum output sig al p wer;
e) maximum total output p wer
Al n merical values fol owed by (‡) are s g ested values for whic the me s rement is
as ured Other values may b ac e ta le but s ould b verified
This p rt of IEC 612 0-1 a pl es to sin le-c an el ampl fiers For multic an el ampl fiers, the
IEC 612 0-10 series a pl es
The fol owin doc ments, in whole or in p rt, are normatively referen ed in this doc ment an
are in isp n a le for its a pl cation For dated referen es, only the edition cited a ples For
u dated referen es, the latest edition of the referen ed doc ment (in lu in any
amen ments) a pl es
IEC 6 7 3-1-4 , Optc l fibre s – Part 1-40 : Mea ureme nt me th ds and te st p ro cedure s –
Ate nu ato
IEC 612 0-1, Optc l amplfiers – Te st meth ds – Part 1: Po we r andg ain parame te rs
IEC 612 1-1, Optc l amplfie rs – Part 1: G ene ric sp e c ific to
3 Terms, definitions and abbreviations
3.1 Terms a d definitio s
For the purp ses of this doc ment, the terms an definition given in IEC 612 1-1 a ply
Trang 83.2 Abbre iations
ASE amplfied sp ntane u emis ion
DBR distributed Brag reflector (laser diode)
DFB distributed fe db c (laser diode)
POWA planar o tical waveg ide amplfier
SOA semicon u tor o tical ampl fier
4 Apparatus
A diagram of the me s rement set up is given in Fig re 1
Trang 9Figure 1a) Me surement of in ut signal p wer
Figure 1b) Me surement of o tic l ban pa s fi ter los an jumper los
Figure 1c) Me surement of o tp t signal p wer an g in
Figure 1d) Me surement of total o tp t p wer
Figure 1 – Typic l ar a g me t of optic l power
meter te t apparatus for me s reme t
The test eq ipment l sted b low, with the req ired c aracteristic , is ne ded
a) o tc l source: The o tical source s al b either at fixed wavelen th or wavelen th
Trang 10– fix d-wav le gth op tical sourc e : This o tical source s al generate a l g t with a
wavelen th an o tical p wer sp cified in the relevant detai sp cification Unles
otherwise sp cified, the o tical source s al emit a contin ou wave with FWHM of the
sp ctrum nar ower than 1 nm (‡) A distributed fe db c (DF ) laser, a distributed
Brag reflector (DBR) laser, an external cavity laser (ECL) diode, a l g t emit in diode
(LED) with a nar ow-b n fi ter an a sin le lne laser are a pl ca le, for example
The s p res ion ratio for the side modes for the DFB laser, the DBR laser or the ECL
s al b hig er than 3 dB (‡) The output p wer flu tuation s al b les than 0,0 dB
(‡), whic may b b ter ataina le with an o tical isolator at the output p rt of the
o tical source Sp ctral bro denin at the foot of the lasin sp ctrum s al b minimal
for laser sources, an the ratio of the source p wer to total sp ntane u emis ion
p wer of the laser s al b more than 3 dB
– wav le gth-u neab le op tic l source: This o tical source s al b a le to generate a
wavelen th- u e ble l g t within the ran e sp cified in the relevant detai sp cification
Its o tical p wer s al b sp cified in the relevant detai sp cification Unles
otherwise sp cified, the o tical source s al emit a contin ou wave with the ful width
at half maximum (FWHM) of the sp ctrum nar ower than 1 nm (‡) An ECL or an LED
with a nar ow b n p s o tical fiter is a pl ca le, for example The s p res ion ratio
of side modes for the ECL s al b hig er than 3 dB (‡) The output p wer flu tuation
s al b les than 0,0 dB, whic may b b t er ataina le with an o tical isolator at
the output p rt of the o tical source Sp ctral bro denin at the fo t of the lasin
sp ctrum s al b minimal for laser sources an the ratio of the source p wer to total
sp ntane u emis ion p wer of the laser s al b more than 3 dB
b) o ptc l po we r meter: It s al have a me s rement ac urac b ter than ±0,2 dB,
ir esp ctive of the state of p larization, within the o erational wavelen th b n width of the
OA A maximum o tical input p wer s al b large enoug [e.g + 0 dBm (‡)] Sen itivity
s al b hig enou h [e.g – 0 dBm (‡)] A d namic ran e ex e din the me s red gain is
req ired (e.g 4 dB)
c) o ptc l iso lato r: Optical isolators may b u ed to brac et the OA The p larization
-de en ent los (PDL) of the isolator s al b b ter than 0,2 dB (‡) Optical isolation s al
b b ter than 4 dB (‡) The reflectan e from this device s al b smal er than – 0 dB (‡)
at e c p rt
d) variable op tic al ate uator: The aten ation ran e an sta i ty s al b over 4 dB (‡) an
b ter than ± 0,1 dB (‡), resp ctively The reflectan e from this device s al b smal er
than – 0 dB (‡) at e c p rt
e) p olariz to c o ntrole r: This device s al b a le to provide as input sig al l g t al p s ible
states of p larization (e.g l ne r, el ptical an circ lar) For example, the p larization
control er may con ist of a l ne r p larizer fol owed by an al - ibre- yp p larization
control er, or by a l ne r p larizer fol owed by a q arter-wave plate rotata le by minimum
of 9 ° an a half wave plate rotata le by minimum of 18 ° The los variation of the
p larization controler s al b les than 0,2 dB (‡) The reflectan e from this device s al
b smal er than – 0 dB (‡) at e c p rt The u e of a p larization controler is con idered
o tional, ex e t for the me s rement of p larization de en ent gain, but may b
neces ary to ac ieve the desired ac urac for OA devices ex ibitin sig ificant
p larization de en ent gain
f o ptc l fibre ju mp rs: The mode field diameter of the o tical fibre jump rs u ed s ould b
as close as p s ible to that of fibres u ed as input an output p rts of the OA The
reflectan e from this device s al b smal er than – 0 dB (‡) at e c p rt, an the len th
of the jump r s al b s orter than 2 m
Stan ard o tical fibres defined in IEC 6 7 3-2-5 , B1 are recommen ed However, other
fib r typ may b u ed as inputoutput fiber In this case, the typ of fibre wi b
con idered
g) o ptc l c on e c to rs: The con ection los re e ta i ty s al b b t er than ± 0,2 dB The
reflectan e from this device s al b smal er than – 0 dB (‡)
h) o ptc l b andp as fi er: The o tical b n width (FWHM) of this device s al b les than
3 nm (‡) It s al b either wavelength- u e ble or an a pro riate set of fixed b n p s
Trang 11b n width an the o tical source centre wavelen th s al b no more than 1,5 nm (‡) The
PDL of the b n p s fi ter s al b les than 0,2 dB (‡) The reflectan e from this device
s al b smal er than – 0 dB (‡)
NOT 1 Optimiz tio of o tic l b n p s fiter s e tral width is dis u s d in An e A
i) o ptc l cou p le r: The p larization de en en e of the bran hin ratio of the coupler s al b
les than 0,1 dB (‡).An u con ected p rt of the coupler s al b pro erly terminated, in
s c a way as to decre se the reflectan e b low – 0 dB (‡)
NOT 2 Th c a g of th state of p lariz tio of th in ut lg t is ty ic ly n glgible
j) wav le gth meter: It s al have a wavelen th me s rement ac urac b ter than 0,1 nm (‡)
If the o tical source is so cal brated that the ac urac of the wavelen th is b t er than
0,1 nm (‡), the wavelen th meter is not neces ary
5 Test sample
The OA s al o erate at nominal o eratin con ition If the OA is lkely to cau e laser
os i ation d e to u wanted reflection , u e of o tical isolators is recommen ed to brac et
the OA u der test This wi minimize the sig al in ta i ty an the me s rement u certainty
For al parameter me s rements ex e t p larization-de en ent gain, care s al b taken to
maintain the state of p larization of the input lght d rin the me s rement Chan es in the
p larization state of the input l g t may res lt in input o tical p wer c an es b cau e of the
sl g t p larization de en en y exp cted from al the o tical comp nents u ed, th s le din to
me s rement er ors
6 Procedure
a) Nominal output signalpo we r: The nominal output sig al p wer is given by the minimum
output sig al o tical p wer, for an input sig al o tical p wer sp cified in the relevant
detai sp cification, an u der nominal o eratin con ition , given in the relevant detai
sp cification To fin this minimum value, input an output sig al p wer levels s al b
contin ou ly monitored for a given d ration of time an in presen e of c an es in the
state of p larization an other in ta i ties, as sp cified in the relevant detai sp cification
The me s rement proced res des rib d b low s al b fol owed, with referen e to
Fig re 1
In order to minimize the ampl fied sp ntane u emis ion (ASE) p wer contribution to the
sig al p wer output from the OA, several method may b u ed The o tical b n p s
fiter method is given b low
1) Set the o tical source at the test wavelen th sp cified in the relevant detai
sp cification, me s rin the input sig al wavelen th (e.g with a wavelen th meter)
2) Me s re the bran hin ratio of the o tical coupler throu h the sig al p wer levels
exitin the two output p rts with an o tical p wer meter
3) Me s re the los L
bj
of the o tical b n p s fi ter an the o tical fibre jump r b twe n
the OA an the o tical p wer meter (se Fig re 1(b) by the in ertion los tec niq e
(se Method B in IEC 6 7 3-1-4 )
4) Activate the OA u der test an evaluate the ASE p wer level p s ed throu h the
o tical fiter, PASE, by me s rin the o tical output p wer from the OA, as s own in
Fig re 1(c), without input sig al
NOT 1 In larg -sig al c n itio s, th me s reme t of th AS p wer is s metime omite
NOT 2 For c n id ratio of me s reme t u c rtainty, refer to th la t p ra ra h of An e A, whic
c n ern th o timiz tio of th o tic l b n p s fiter s e tral width
5) Set the o tical source an the varia le o tical aten ator in s c a way as to provide,
at the input p rt of the OA, the input o tical sig al p wer (P
in) sp cified in the relevant
detai sp cification Record the o tical p wer (P
o) me s red with an o tical p wer
Trang 12In tantly a plyin sig al l g t into the active OA can cau e the generation of an o tical
s rge whic may damage the o tical comp nents The input sig al s al have
s f iciently smal p wer to prevent the o tical s rge, when it is lau c ed to the OA
initial y The input p wer s al b grad al y in re sed to the sp cified level
6) Ke p the o tical sig al p wer at the OA input con tant (Pin) d rin the fol owin
me s rements, by monitorin the secon output p rt of the coupler an , if neces ary,
set in the varia le o tical at en ator in s c a way that the o tical p wer (P
o) exitin
the secon output p rt of the o tical coupler remain con tant
7) Con ect the fibre jump rs to the input an output p rt of the OA u der test, as s own
in Fig re 1(c) an evaluate the o tical output p wer (P
o t) with input sig al
In the case u in the p larization control er, the folowin proced re s al b ada ted
8) Set the p larization controler at a given state of p larization as sp cified in the
relevant detai sp cification; activate the OA, an monitor, by me n of the o tical
p wer meter, the o tical sig al p wer at the output of the OA, for the sp cified p riod
of time, recordin the minimum value
9) Chan e the state of p larization of the input sig al by me n of the p larization
control er, tryin to me s re maximum an minimum output o tical sig al p wers with
the o tical p wer meter, an re e t proced re 8)
10) Re e t proced re 9) for the dif erent states of p larization in icated in the relevant
detai sp cification an , final y, take the a solute minimum an maximum output
o tical sig al p wers recorded in the variou con ition : P
o t min
o t ma
Optical con ectors J1 an J2 s al not b removed d rin the me s rement to avoid
me s rement er ors d e to recon ection
The me s rement er or s al b red ced by el minatin the ef ect of the ASE
simultane u ly detected with the sig al This is b ter ataina le by placin an o tical
b n p s fi ter havin the nar ower p s b n at the output of the OA u der test, as it
has b en dis u sed in the main text For large o tical sig al p wer levels, the o tical
b n p s fi ter may not b neces ary to ac ieve an ac urate me s rement The u e of
the o tical b n p s fi ter is imp rtant, esp cial y when the input sig al to the OA is
smal This is b cau e the ASE p wer in re ses as the input sig al decre ses
However, if this kin of o tical fi ter is alre d bui t in the OA, the external o tical fi ter
is not ne ded The ef ectivenes of the o tical b n p s fi ter is further dis u sed in
An ex A
b) Gain and p lariz to dep ende t gain: As from proced res 1) to 7) in a), but this method
p rmits determination of the gain throu h the me s rements of the OA input sig al p wer
P
in
an the OA output p wer P
o ttakin into ac ou t the OA ampl fied sp ntane u
emis ion (ASE) p wer P
AS
at the sig al wavelen th
1 ) Re e t proced res 5) to 7), with in reasin input sig al p wer grad al y to the
maximum input sig al p wer given in the relevant detai sp cification Maintain the
pump p wer or pump c r ent with the firstly set p int Polarization-de en ent gain: as
in a), but this p rameter is determined throu h the me s rements of the OA input
sig al p wer, P
in, the OA output p wer, P
o t min
o tma, takin into ac ou t the
by me n of the p larization control er, so that s bstantial y al the
states of p larization, in prin iple, are s c es ively lau c ed into the input p rt of the OA
u der test
The p larization control er s al b op rated as sp cified in the relevant detai
sp cification A p s ible way, when u in a l ne r p larizer fol owed by a q arter-wave
rotata le plate, is the folowin : the l ne r p larizer is adju ted so that the OA output
p wer is maximized; the q arter-wave plate is then rotated by a minimum of 9 ° ste -
by-ste At e c ste , the half wave plate is rotated by a minimum of 18 ° ste -by-ste
Trang 13A s ort o tical jump r at the OA input, ke t as straig t as p s ible, s al b u ed, in order
to minimize the c an e of the state of p larization in u ed in it by p s ible stres an
anisotro y
The p larization-de en ent los of the o tical con ector s al b les than 0,2 dB (‡)
c) Maximum ou tput signal po we r: As in a), but this p rameter is determined by re e tin al
proced res at diferent wavelen th sp cified in the detai ed sp cification, an re lace
proced res 1), 4), 5) with the fol owin
1) Set the wavelen th- u e ble optical source at a test wavelen th within the sp cified
wavelen th ran e, me s ring the input sig al wavelen th (e.g with a wavelen th
meter)
4) Activate OA an adju t the maximum pump p wer or maximum pump c r ent of OA to
the nominal con ition as sp cified in the relevant detai sp cification When the OA
u der test is integrated with control circ itry, the OA s al b tested with con tant
pump p wer mode or con tant pump c r ent mode
5) Set the o tical source an the varia le o tical aten ator in s c a way as to provide,
at the input p rt of the OA, the maximum input o tical sig al p wer P
smal p wer to prevent the o tical s rge, when it is lau c ed into the OA initial y The
input p wer s al b grad al y in re sed to the sp cified level
d) Maximum total o u tp u t po we r: The maximum total output p wer is given by the hig est
o tical p wer level at the output p rt of the OA o eratin within the a solute maximum
ratin s To fin this maximum value, input an output sig al p wer levels s al b
contin ou ly monitored for a given d ration of time an in presen e of c an es in the
state of p larization an other in ta i ties, as sp cified in the relevant detai sp cification
The me s rement proced res des ribed b low s al b fol owed, with referen e to
Fig re 1
12)Me s re the bran hin ratio of the o tical coupler throu h the sig al p wer levels
exitin the two output p rts with an o tical p wer meter
13)Set the o tical source an the varia le o tical aten ator in s c a way as to provide,
at the input p rt of the OA, the maximum input o tical sig al p wer P
Put in sig al l g t into the active OA can cau e the generation of o tical s rge whic may
damage the o tical comp nents Input sig al s al have s ficiently smal p wer to prevent
the o tical s rge, when it is lau c ed to the OA in the b gin in An the input p wer
s al b grad al y in re sed to a certain level
14)Ke p the o tical sig al p wer at the OA input con tant (P
in-ma) d rin the fol owin
me s rements by monitorin the secon output p rt of the coupler an , if neces ary,
set in the varia le o tical at en ator in s c a way that the o tical p wer (P
o) exitin
the secon output p rt of the o tical coupler remain con tant
15)Con ect the fibre jump rs to the input an output p rt of the OA u der test, as s own
in Fig re 1(d) an activate OA an adju t the maximum pump p wer or maximum
pump c r ent of OA to the a solute maximum ratin s, given in the relevant detai
sp cification When the OA u der test is integrated with control circ itry, the OA s al
b tested with con tant pump power mode or con tant pump c r ent mode, an
evaluate the o tical output p wer (P
total-o t) with input sig al
If the p larization control er is u ed, proced res 5), 6), 7) s al b fol owed
16)Set the p larization controler at a given state of p larization as sp cified in the
relevant detai sp cification; activate the OA, an monitor, by me n of the o tical
p wer meter, the o tical sig al p wer at the output of the OA, for the sp cified p riod
Trang 1417)Chan e the state of p larization of the input sig al by me n of the p larization
control er, tryin to me s re maximum an minimum output o tical p wers with the
o tical p wer meter, an re e t proced re 5)
18)Re e t proced re 6) for the dif erent states of p larization in icated in the relevant
detai sp cification, an final y take the a solute minimum an maximum output o tical
p wers recorded in the variou con ition : P
total-o tmin
total-o t ma
Optical con ectors J1 an J2 s al not b removed d rin the me s rement to avoid
me s rement er ors d e to recon ection
The me s rement er or s al b red ced by el minatin the ef ect of the ASE
simultane u ly detected with the sig al This is b t er at aina le by placin an o tical
b n p s fi ter havin the nar ower p s b n at the output of the OA u der test, as it has
b en dis u sed in the main text For large o tical sig al p wer levels, the o tical
b n p s fi ter may not b neces ary to ac ieve an ac urate me s rement The u e of
the o tical b n p s fi ter is imp rtant, esp cial y when the input sig al to the OA is smal
This is b cau e the ASE p wer in re ses as the input sig al decre ses However, if this
kin of o tical fi ter is alre d bui t in the OA, the external o tical fi ter is not ne ded The
efectivenes of the o tical b n p s fi ter is further dis u sed in An ex A
o t– P
AS) + L
is the in ertion los of the o tical b n p s fi ter an fibre jump r placed b twe n
the OA an the o tical p wer meter (in dB)
NOT 1 If o tic l b n p s fiter is alre d b it in th OA, th e tern l o tic l fiter is n t n e e In this
c s , th in ertio lo s L
bj
is e u l to th t of th fibre jump r
NOT 2 A c mp ris n of th me s re v lu s o tain d with OSA, with th c lc late v lu s with o tic l
p wer meter u in v rio s b n p s fiters, is refer e to in An e A
b) G ain: The gain G at the sig al wavelen th s al b calc lated as
G = (P
o t – P
AS) P
o t– P
AS) P
AScould b negl gible with resp ct to P
o t
A comp rison of the
me s red values o tained with OSA, with the calc lated values with o tical p wer meter
u in variou b n p s fi ters, is refer ed to in An ex A
NOT 3 Th smal-sig al re ime is wh n th OA u d r te t o erate in th ln ar re ime, whie th larg
-sig al re ime is in th s turate re ime Th distin tio b twe n smal-sig al a d larg -sig al re ime c n b
c nfirme b plotin G v rs s th in ut sig al p wer Th ln ar re ime d ma d th time-a era e in ut
Trang 15c) Po lariz to n-dep ende t gain: Calc late the gain values at the dif erent states of
p larization as des rib d in b) Calc lation are proces ed u in the fol owin proced re
1) Calc late the gain values at the dif erent states of p larization, as in b)
d e n t n c s ariy in ic te th p s ible ma imum v riatio of th p lariz tio
d p n e c This is b c u e th ate u tio thro g th OA u d r te t is ma imum o ly wh n e c in ut
state of p lariz tio simulta e u ly yield ma imum ate u tio for e c c mp n nt in th OA u d r te t
NOT 7 Th me s reme t eror c n b b ter th n ± 0,5 dB (‡), d p n in mainly o th o tic l p wer
meter p lariz tio d p n e c
The input sig al p wer at whic the p rameter is sp cified an me s red s ould b stated
L rger input p wer is recommen ed con iderin the ASE factor contained in the output
2) sp ctral l newidth (FWHM) of the o tical source
3) in ication of the o tical pump p wer an p s ibly drivin c r ent of pump lasers for
OFAs, an injection c r ent for SOAs (if a pl ca le)
4) o eratin temp rature (if req ired)
10) c an e in the state of p larization given to the input sig al l g t
b) Gain: The detai s 1) to 8), previou ly l sted for the nominal o tical sig al p wer levels,
s al b presented an , in ad ition
1 ) gain
Parameters 5) an 9) may b re laced with the gain vers s input o tical sig al p wer
c rve
Trang 16Parameters 8) an 10) may b re laced with the gain vers s input sig al wavelen th
14) p larization-de en ent gain
15) c an e in the state of p larization given to the input sig al l g t
d) Maximum output signal po we r: The detai s 1) to 8), previou ly lsted for the gain, s al b
Trang 17Annex A
(informative)
Optimization of optical bandpass fi ter spectral width
The me s rement u certainty of this method de en s on the c oice of the b n p s fiter,
e.g in terms of the sp ctral width (FWHM) In fact, as mentioned, the purp se of this fi ter is
to can el the ASE contribution from the me s rement As s c , it is intuitive that the smal er
the fi ter FWHM is c osen the gre ter is the ASE can el ation an hen e the me s rement
u certainty However, if the fi ter sp ctral width is ex es ively nar ow, pro lems of al g ment
b twe n the fiter central freq en y an the sig al freq en y can arise, le din to sta i ty
pro lems whic can b detrimental to me s rement u certainty These con ideration
in icate that an o timal sp ctral width of the fiter s ould b c osen to minimize the
me s rement u certainty
A p s ible proced re to determine s c an o timal fi ter is to calbrate this o tical p wer
meter (OPM) method with the OSA tec niq e (se IEC 612 0-1-1), intrin icaly more ac urate
For a given OA typ log , OPM me s rements u in s c es ively diferent fiters (with FWHM
e.g from 1 nm to 5 nm) can b comp red with an OSA me s rement The o timal b n p s
fi ter to b c osen wi be the one whic minimizes the dif eren e b twe n the res lts from the
two me s rement method
For example, a plyin this cal bration proced re in a n merical y simulated case, the u e of a
b n p s fi ter of L rentzian typ with FWHM of 2 nm demon trated to s ficiently can el the
ef ect of ASE an ac ieve a diferen e with resp ct to OSA me s rements res lt les than
only 0,0 dB This dif eren e in re sed to a proximately 0,15 dB for a fi ter with FWHM of
5 nm It s ould b noted that, whi e the efect of ASE can b ac urately evaluated in smal
-sig al regime, even in large-sig al regime, notwith tan in les ac urate evaluation of ASE
p wer, the p rtion of ASE p wer b comes les sig ificant with resp ct to the sig al p wer As
a res lt, an ac urate OPM me s rement can b maintained over entire input sig al levels by
c o sin an o timal y nar ow FWHM of b n p s fi ter
Trang 18Bibl ography
IEC 6 7 3-1-1, Op tic al fib re s – Part 1-1: Mea ureme t meth ds and test p ro cedures –
G en ral and gu idanc e
IEC 6 7 3-2-5 , Optc l fib re s – Part 2-5 : Product spe c ificato ns – Secto al spe cific to
fo r c la s B single -mode fibre s
IEC 6 8 5-1, Safety o f la e r p ro duc ts – Part 1: Equ ipme nt c la sificato n and re u ireme ts
IEC 6 8 5-2, Safe ty of la erp roducts – Part 2: Safety of op tical fibre communic ato systems
(OFC S)
IEC 6 8 4-1, Fibre op tic inte rco ne ctn de vic e s and p as iv compo ne ts – C on ecto rs for
o ptc l fibre s and c b le s – Part 1: G ene ric sp e c ific ato
IEC 612 0-1-1, Optc l amplfie rs – Te st me th ds – Part 1-1: Powe r and gain paramete rs –
Op tic al sp ctru m analyzerme th d
IEC 612 0-10 (al p rts), O p tic al amplfie rs – Te st me th ds – Part 10: Mu ltchan e l
parame te rs
IEC TR 619 1, Fibre o ptc – Te rmino lo y
_ _ _ _ _ _ _