TELKOM
NIKA
, Vol. 11, No. 2, Februa
ry 2013, pp. 948~953
ISSN: 2302-4
046
948
Re
cei
v
ed Se
ptem
ber 17, 2012; Revi
se
d Jan
uary 2, 2012; Accept
ed Ja
nua
ry 1
5
, 2013
Resear
ch on OSNR and BER of 40G DWDM System on
DRZ
FENG Xianc
h
eng*, LI Xiaopeng, SI Qinghua
Coll
eg
e of Elec
trical an
d Elect
r
onic En
gin
eer
i
ng
W
uha
n Insti
t
ute of
T
e
chnol
og
y, W
uhan
43
007
3, Chi
n
a
*Corres
p
o
ndi
n
g
author, e-ma
i
l
: xcfen
g68
@h
otmail.com
A
b
st
r
a
ct
The
signal
mo
du
latio
n
format
is
a
k
e
y issue for 4
0
G
DWDM fiber optical c
o
mmunic
a
tion syste
m
,
w
h
ich deter
mi
n
e
s transmissio
n
qua
lity and s
pectral effici
en
cy. F
i
rstly, the
sche
m
e of key
technol
ogi
es a
n
d
m
o
dulation for
m
at (ODB, CS
RZ, DRZ, DPSK, DQPSK) of
40G DWDM sy
stem
is introduced. Through t
h
e
Q value w
i
th
OSNR an
d B
E
R, the theor
etical c
u
rve b
e
tw
een OSNR
and BE
R is
give
n. And th
en i
t
prop
oses o
p
tic
a
l interfac
e p
a
r
ameters req
u
i
r
em
ents of 40
G DWDM system. By w
a
y o
f
adopti
ng VO
A
compe
n
satio
n
i
n
exp
e
ri
me
ntal
system, OTU typica
l s
pectru
m
,eye
dia
g
ra
m, BER and OS
NR perfor
m
anc
es
have
bee
n te
sted an
d an
al
y
z
e
d
. Exper
iment result
s sh
ow
that DRZ
code
have
be
tter transmiss
i
o
n
perfor
m
a
n
ce, are
su
itab
le
fo
r
lon
g
or mid
d
le dist
a
n
ce tr
ans
missi
on,
meet the
de
ma
nd
of co
mmer
ci
a
l
app
licati
on.
Ke
y
w
ords
:
D
W
DM, 40G Modul
ation F
o
r
m
a
t, OSNR
，
BER
，
Differential Retu
rn Zero Code
Copy
right
©
2013 Un
ive
r
sita
s Ah
mad
Dah
l
an
. All rig
h
t
s r
ese
rved
.
1. Introduc
tion
It is the
incre
a
sin
g
cap
a
cit
y
and
rate
re
quire
ment th
at improve th
e devel
opme
n
t of 40
G
DW
DM
Tb/
s
sy
st
em,
su
ch
as
B
r
oad
ban
d, IPTV, Tripl
e
Play, P2P,
et
c. In recent
years, OF
C a
nd
ECOC h
a
ve repo
rted a g
r
eat numbe
r
of transmi
ss
i
on experi
m
e
n
ts in labo
rat
o
rie
s
or te
sting
grou
nd
s of
4
0
Gbp
s
WDM
syste
m
. Nu
mero
us eq
ui
pment m
anuf
acturers
hav
e be
en
con
s
t
antly
laun
ching different kind
s of
module
s
compatible
to
40Gb
p
s to
meet the ap
plicatio
n of 4
0
G
interface. Some leadin
g
equipm
ent m
anufa
c
ture
rs have ann
oun
ced to p
r
ovi
de high
-capa
city
WDM tra
n
smi
ssi
on
syste
m
with
40G
int
e
rface.
While
releva
nt te
ch
nologi
es are
well-develo
p
e
d
,
40G t
r
an
smi
ssi
on i
s
in
l
a
ck of
co
rre
s
po
ndin
g
st
a
ndards. A
c
co
rding
to a
survey by
He
avy
Rea
d
ing, 60
% of operators will choo
se
40G opti
c
-n
etwork technol
ogy in three years. The ma
rke
t
scale of 40G
techn
o
logy wi
ll reac
h 2 billi
on dolla
rs u
n
til 2010[1-4].
2. Ke
y
Technologies of
40G Sy
stem
2.1. The Mod
u
lation Co
de
T
y
pe Techn
o
log
y
of 40G
To impleme
n
t
40G DWDM system, these key te
chn
o
logie
s
should be ta
ken into
con
s
id
eratio
n
:
In a 40G
bp
s sy
stem, it i
s
ne
ce
ssa
r
y to further in
crea
se th
e em
issi
on p
o
wer
of
optical
sign
al
s to meet the
deman
d of O
S
NR. As
a
re
sult, the nonli
near
effect of
optical fibe
r
will
lead to the
seri
ou
s di
sto
r
tion of
NRZ
-co
de o
p
tical
sign
al. The
new
mod
u
lation code t
y
pe,
combi
n
ing various modulat
ion
modes such as ODB, CSRZ,
DRZ
,
DPSK, DQPSK and
so
on,
has b
e
come
the major
co
de type in 40
Gbp
s
WDM
system for its excellent propertie
s
[5-7]. In
addition, th
e
sel
e
ctio
n o
f
modulatio
n
format
of
40Gb
p
s high
-sp
eed
DWDM optical fi
ber
transmissio
n
system i
s
rel
e
vant to the
overall
d
e
si
g
n
ing of the e
n
tire sy
stem,
whi
c
h in
clud
es
asp
e
ct
s like t
y
pe of opti
c
al
fiber, inte
rval
of tr
an
smi
ssi
on
system, di
stan
ce, n
u
mb
er of
ch
annel
s,
interval of
ch
annel
s. In te
rms of t
r
an
smi
ssi
on p
h
ys
i
c
a
l
effect, not o
n
ly disp
ersio
n
and
inte
r-b
and
nonlin
ear effe
ct but also P
M
D and in
-b
a
nd nonli
nea
r effect sho
u
ld
be co
nsi
dere
d
[8-10].
2.2. The Rela
tionship be
tw
e
e
n
OS
NR
and BE
R
Optical
sign
al con
s
ist
s
of modulate
d
m
a
rk
a
nd spa
c
e. In ASK direct dire
ction
system,
mark
“1” an
d
sp
ace “0” is
rep
r
e
s
ente
d
by non
-opti
c
a
l
pul
se. If “1”
and
“0
” b
eha
ve acco
rdin
g
to
Gau
ssi
an di
stribution, then
Evaluation Warning : The document was created with Spire.PDF for Python.
TELKOM
NIKA
ISSN:
2302-4
046
Re
sea
r
ch on
ONSR
and B
E
R of 40G DWDM System
on DRZ (FE
N
G Xian
che
n
g
)
949
)
2
exp(
2
1
2
Q
Q
BER
(1)
Q for Quality factor, eg.
9
10
BER
Q=6
，
Figu
re 1 is the relation curve between
BER and Q.
Figure 1. The
Relation
Curve Between
BER
and Q
Figure 3. The
Relation
Curve of BER and
OSNR
av
g
2.3. The Rela
tion bet
w
e
e
n
Q and SNR
Q rep
r
e
s
ent
s quality factor, a useful in
d
e
x to
descri
b
e system
noi
se p
e
rfo
r
man
c
e. Even
though th
e value of BER
is lo
w, Q can
be prec
i
s
ely
measured.
Q ca
n be
re
pre
s
ente
d
by
the
func
tion of OSNR (mainly ASE noi
s
e
) through trans
f
ormation.
OSNR
OSNR
p
p
mP
P
m
mP
mP
P
P
P
P
P
P
Q
N
S
N
S
N
N
N
S
S
BEAT
BEAT
S
2
1
1
2
1
1
2
1
2
0
1
2
2
2
2
0
1
0
1
(2)
P
s
for amplification sig
nal p
o
we
r, P
N
for ASE power,
m for polari
z
ation mode (m
=1 or
2),
2
BEAT
for ASE beat noise.
OSNR
P
P
mP
P
total
ASE
S
N
S
，
m=
2
(3)
Q = 6, then OSNR=44.5 or
16.4dB. Notice that
the average OS
NR of signal modulated by ASK
is lower than
this value: O
S
NR
av
g
=13.4
d
B. Figure 2 i
s
the relatio
n
curve b
e
twe
e
n
OSNR and
Q.
Usi
ng eq
uatio
n (1)
(2) to co
nne
ct BER and OSNR
through Q. Figu
re 3 is the rela
tion curve of
BER and OS
NR
av
g
Figure 2. The
Relation
Curve Between
OSNR
and Q
2.4. OSNR
Budget
In a
optical
fiber comm
unication
sy
stem,
the
si
gnal
disto
r
tio
n
an
d
OSNR of
the
receiver’
s
inp
u
t end is th
e most imp
o
r
tant fact
o
r
to determine
the ch
ara
c
te
ristic of BER in
sy
st
em.
The
f
o
llowin
g
f
u
rt
her
di
sc
us
se
s som
e
im
p
o
r
tant p
r
in
ciple
s
of
sy
stem
desi
gning,
ba
sed
on the req
u
irement of OSNR.
0
5
10
15
20
10
-2
0
10
-1
5
10
-1
0
10
-5
10
0
O
S
N
R
av
g(
dB
)
Îó
Â
ëÂ
Ê
BER
0
2
4
6
8
10
10
-2
5
10
-2
0
10
-1
5
10
-1
0
10
-5
10
0
10
5
Q
BER
0
2
4
6
8
10
12
0
20
40
60
80
100
120
QÖ
µ
Ð
Å
Ô
ë±
È
S
N
R
0
2
4
6
8
10
10
0
10
1
10
2
QÖ
µ
Ð
Å
Ô
ë±
È
S
NR(
d
B
)
Evaluation Warning : The document was created with Spire.PDF for Python.
ISSN: 23
02-4
046
TELKOM
NIKA
Vol. 11, No. 2, Februa
ry 2013 : 948 – 953
950
Definition of
OSNR:
P
sig
for avera
ge o
p
tical
po
wer of
ce
rtai
n chan
nel, P
si
g
=P
out
-10log
M; P
out
for E
D
FA total
output po
wer;
M for chan
n
e
l numbe
r;
P
ASE
=F (G-
1
) h
v
Bo ( N
+
1
)
fo
r amplified A
SE inside EDFA,
noise po
we
r i
n
optical filter band
width
Bo
ca
scad
ed b
y
N+1
optical f
i
ber
se
ction
a
nd EDFA.
Bo
is
usu
a
lly defin
ed to be
12.6
GHz (0.1nm
), or 10lo
g
(
hvBo
)=-58
dBm
in de
cibel
s,
F for EDFA
n
o
ise
coeffici
ent an
d G for amp
lification mult
iple
. If every EDFA has the sam
e
gai
n and exactl
y
cou
n
tera
ct st
he loss of opt
ical fiber
se
ction, then
(4)
Due t
o
the i
n
cre
a
se of
P
AS
E
and the
len
g
th of opti
c
al
fiber
se
ction f
o
llowed by th
e linea
r
increa
se of amplifier’
s pro
g
re
ssi
on, low gai
n with more prog
re
ssi
on has mu
ch
higher OS
NR
than high g
a
i
n
with less progre
s
sion
wh
en the total system length
maintain
s the
same.
In fac
t, the los
s
of
N optical fiber sec
t
ions
i
s
not the
same. B
u
t ea
ch l
e
vel of E
D
FA g
a
in
is possibl
e to be con
s
id
e
r
ed a
s
line loss (
L
i
=
G
i+1
) to make u
p
for the former opti
c
al fiber
se
ction, be
ca
use E
D
FA m
a
inly wo
rks i
n
(de
ep)
sat
u
rated
co
ndit
i
ons. In en
gi
neeri
ng de
si
gn
,
given the
fact
that ea
ch
opt
ical
amplifier
mainly
works
in saturate
d
condition
s, tot
a
l outp
u
t po
wer
remai
n
ing un
cha
nge
d, the gain of operating point
wi
ll spontan
eou
sly adapt to the sam
e
as the
former
optical
fiber se
ction’
loss, which is
different
with rated gai
n. As a re
sult, OSNR:
(5)
Acco
rdi
ng to
the line
lo
ss,
the
OSNR e
v
ol
utionary p
r
ocess
of DWDM system
ca
n
b
e
estimated, which i
s
of vital guiding
signif
i
can
c
e in e
ngi
neeri
ng for n
e
twork pla
nni
ng.
Take e
qual
-lo
ss o
p
tical fibe
r se
ction for e
x
ample,
we can obtain the
total output powe
r
of EDF
A
:
(6)
⊿
P
[
dB
] is the cha
nnel p
o
w
er
differen
c
e cau
s
e
d
by variou
s facto
r
s (su
c
h a
s
EDFA and
wavele
ngth chara
c
te
risti
c
s of each com
pone
nt’s gain
or loss, nonli
near effe
ct of optical fiber). It
can al
so be
con
c
lu
ded th
at when EDFA total output powe
r
mai
n
tains the sa
me, numbe
r of
cha
nnel
s M a
nd numb
e
r of
optical fiber
se
ction
s
sh
ou
ld meet:
(7)
For
example,
data
rate of
ch
annel
=
4
0
Gbp
s
(OSNR lo
we
r limit
=2
0dB), E
D
FA total
output po
wer= 23
dB
m, F=8dB,
P=3dB
，
G
=
22
dB(0.2
75
dB/km×80
km
), and then
M(N+1
)
=631
，
M=40, thu
s
N=14.
I
n
sum,
40
G
DW
DM
sy
st
e
m
is a
sop
h
is
t
i
cat
ed inte
grated sy
stem
whi
c
h
combi
n
es late
st
cod
e
-type
mo
dulating
tech
nology, m
ana
gement
techn
o
logy of
stron
g
di
spe
r
sion,
high tol
e
ra
nce
of OSNR, hig
h
sen
s
itivity of testing and re
ceivin
g and
codi
ng erro
r correctin
g
tech
nology.
3. Optical Interfa
ce of 4
0
G
WDM Sy
st
em
The refe
ren
c
e config
uratio
n of 40G DWDM syst
em is sh
own in Figure 4. In it, OUT for
optical
wavel
ength
conve
r
t
e
r to fulfill 3
R
function
(re-amplifying, re
-formin
g
, re
-ti
m
ing); O
M
U f
o
r
optical m
u
ltipl
e
xer unit to f
u
lfill multiplexing of va
rious wavelength; OA for opti
c
al
amplifying unit
to fulfill signal opti
c
al domain amplificatio
n (including di
spersi
on
compensation); ODU for
photolysi
s
mu
ltiplexer unit to fulfill photolysis mult
iplex
i
ng of various wavelength;
Tx/Rx for client
side
-light inte
rface.
Figure 4 defines 6 refe
re
nce poi
nts o
u
tside
the sy
stem and 2 i
n
sid
e
, and they are S,
MPI-SM, RM, SM, MPI-RM, R and Sn, Rn. Among the
m
, R and S are interfa
c
e
referen
c
e p
o
in
ts
of MS-UL
H
WDM syste
m
and cu
sto
m
er
system.
MPI-SM, RM, SM, MPI-
RM are refe
rence
Pout
[
dB
m
]
=
G
[
dB
]
F
[
dB
]
OS
NR
[
dB
]
10
log
[
M
(
N
1)]
+⊿
P
[
dB
]
58
OSNR
[d
B
]
=
P
out
[
d
Bm
]
-10
l
og
M
+58-
NF
[d
B
]
-
10
log
[
G
(1)
+
1
)
(
N
i
L
]
OSNR
[d
B
]
≈
P
ou
t
[
dBm
]
-10
l
og
M
+58-[
NF
[d
B
]
+G
[d
B
]
+
10
l
o
g
(N+
1
)
]
M
(
N
1
)≤10
0.1
(
58+
P
ou
t
[
dBm
]
G
[
dB
]
F
[
dB
]
OSNR
[
dB
]
⊿
P
[
dB
]
)
OSNR
P
sig
/
P
ASE
Evaluation Warning : The document was created with Spire.PDF for Python.
TELKOM
NIKA
ISSN:
2302-4
046
Re
sea
r
ch on
ONSR
and B
E
R of 40G DWDM System
on DRZ (FE
N
G Xian
che
n
g
)
951
points
of m
a
in opti
c
al
chann
el of M
S
-UL
H
WDM system;
Sn, Rn a
r
e
referen
c
e p
o
ints
respe
c
tively betwe
en O
U
T and OM
U, ODU in
M
S
-UL
H
WDM system.
And the sp
e
c
ific
meanin
g
s of these refe
ren
c
e points a
r
e a
s
follows:
Figure 4. The
Refere
nce Confi
guration o
f
40G DWDM
System
S for
refe
ren
c
e poi
nt at
opti
c
al fib
e
r joint
after the
cust
om
sign
al em
itter outp
u
t int
e
rface;
Sn for refe
rence point a
t
optical fibe
r joint after
OUT’
con
n
e
c
tion to OMU output
interface;
MPI-SM for referenc
e point at optic
al fiber
joint after
OA, after OMU, output interfac
e;
RM for refere
nce p
o
int at optical fiber joi
n
t before OA
input interfa
c
e;
SM for refere
nce p
o
int at optical fi
ber joi
n
t after OA output interface;
MPI-RM for referen
c
e p
o
in
t at optical fiber
joint befo
r
e
OA, before ODU, input in
terface;
Rn fo
r
refe
re
nce
poi
nt at
optical
fiber j
o
in
t befo
r
e
in
put inte
rface
con
n
e
c
ting
O
U
T, after
ODU;
R for refe
ren
c
e point at optical fiber joi
n
t bef
ore
cu
sto
m
er si
gnal re
ceiver in
put interface.
4. Testing an
d Analy
s
is
4.1 Con
f
igur
ation Tes
t
in
g
OTU p
e
rfo
r
m
ance testing
of 40G DWDM
system is
shown in Figu
re 5.
Figure 5. Con
f
iguration
Dia
g
ram
of 40 G
OTU Pe
rform
ance Test
Figure 6. Co
nfiguratio
n di
agra
m
of 40 G OTU OS
NR Perfo
r
man
c
e Te
st
Among them,
VOA represe
n
ted in dotted
line mean
s t
o
add in p
r
op
er VOA wh
en
testing
eye pattern p
e
rform
a
n
c
e
so as to ma
ke
it meet
the d
e
mand
of inp
u
t optical
po
wer re
qui
rem
ent
rang
e of
co
mmuni
cation
sign
al an
al
yzer. Th
e d
eployment di
agra
m
of B
E
R and
OS
NR
perfo
rman
ce
testing of 40
G DWDM
system is sh
own
as Figu
re 6.
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ISSN: 23
02-4
046
TELKOM
NIKA
Vol. 11, No. 2, Februa
ry 2013 : 948 – 953
952
4.2 Wav
e
length Co
nv
erter and Sy
stem Experiment
1) 40G
DWWM Wavelen
g
th Conve
r
ter
Spectrum an
d Eye diagra
m
DRZ
40
G DWWM wavele
ngth conve
r
te
r spe
c
tr
um
an
d eye
diag
ra
m are
sho
w
n
Figure 7.
The typical -3
dB spe
c
trum
width of DRZ
module i
s
0.6
n
m.
Figure 7. DRZ 40G DWDM OTU Typi
cal Spectrum
Figure 8. DRZ 40G DWDM OTU Typi
cal Eye Diagra
m
Acco
rdi
ng to
the test results, 40G
wavel
engt
h
conve
r
ter of DRZ
ca
n co
ntinue to
use th
e
curre
n
t WDM
system fre
q
uen
cy, but it has
wi
de
r spectrum wi
dth and lo
we
r
duty ratio th
an
norm
a
l NRZ.
2) OSNR an
d
BER Performance of 40
G DWDM
Wa
velength Con
v
erter
A
cco
rdi
ng t
o
t
e
st
re
sult
s f
r
om Figu
re 9,
the lowe
st tolerated
OSNR of DRZ 40
G
DWDM
wavele
ngth converte
r at E-03 error
rate i
s
app
roximat
e
ly 14dB.
Figure 9. 40G
DWDM System back-to-b
ack
Testing of BE
R and OS
NR
Based o
n
DRZ
Figure 10. 40
G DWDM 1
6
00km lo
ng
-fib
er
Tran
smi
ssi
on
BER and OS
NR
Curve
In Figu
re
1
0
, 166
0km
long
-fibe
r
transmissio
n
syste
m
ha
s impl
eme
n
ted p
r
e
-
comp
en
satio
n
of dispe
r
si
o
n
. The
singl
e
cha
nnel t
r
an
smissio
n
opti
c
al p
o
wer i
s
4dBm/ch,
so
the
lowe
st OSNR of 1600km lo
ng-fibe
r tran
smissi
on is a
p
p
roximately 1
8
.6dB.
3) The T
r
an
smissi
on Perfo
r
man
c
e of 40
G DWDM
Wa
velength Con
v
erter
1.
DRZ 4
0
G
DWDM Wavele
ngth Co
nvert
e
r
System Transmi
ssion O
S
NR Perfo
r
m
ance
2.
The
Di
spe
r
si
on T
o
leran
c
e
of
DRZ
40
G
DW
DM
Wav
e
length
Conv
erter throug
h
System
Tran
smi
ssi
on
Figure
11 i
s
the disp
ersi
on win
d
o
w
af
ter DRZ tra
n
s
mitting 16
00
km; we
can
see th
at the di
sp
ersion
win
d
o
w
i
s
ve
ry sm
all of
40
ps/n
m
with a
dding
the
win
dow by
config
urin
g T
DC.
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TELKOM
NIKA
ISSN:
2302-4
046
Re
sea
r
ch on
ONSR
and B
E
R of 40G DWDM System
on DRZ (FE
N
G Xian
che
n
g
)
953
Figure 11. 40G DWDM Transmi
ssion
1
600
km S
y
st
e
m
Disp
er
sio
n
Curv
e
5. Conclusio
n
Diffe
rent modul
ation code
s h
a
ve different
ch
a
r
a
c
teri
sti
cs
of optical
sign
al ch
an
nel
transmissio
n. To cho
o
se whi
c
h mod
u
l
a
tion co
de to
be adopte
d
i
n
a spe
c
ific
h
i
gh sp
eed o
p
t
ical
transmissio
n
sy
stem,
we
sh
ould
ta
ke
the
actu
al
deman
d i
n
to
acco
unt
an
d cond
uct
some
compl
e
x syst
em simulatio
n
s or expe
ri
ments. To
ju
dge a modul
ation cod
e
, we shoul
d reg
a
rd of
not only its capability of di
spe
r
si
on resi
stan
ce,
pol
ari
z
ation m
ode
disp
ersion
re
sista
n
ce, and
the
negative effe
cts of n
on-li
n
ear
re
sista
n
ce, but also
its ba
nd
width
efficien
cy an
d noi
se imm
u
nity.
No
wad
a
ys, optical tra
n
smissi
on sy
stem based o
n
NRZ
cod
e
has be
en
use
d
in Chi
na’s
Comm
uni
cati
on Netwo
r
k in vast
scale. Ho
weve
r, from 2
0
0
6
, som
e
tel
e
com
m
uni
cat
i
on
comp
anie
s
i
n
Chi
na
have
begu
n u
s
in
g
optical
tran
smissi
on
syst
e
m
with
a
sp
e
ed of
40
Gb/
s
fo
r
field trial and tes
t, to meet the requirement of
sy
stem upg
ra
de.
From th
e re
sults
of pract
i
cal
appli
c
ation
s
,
we’ve fo
und t
hat the
syste
m
with
a
spe
ed of
40
G m
u
st u
s
e
mod
u
l
ation
code
from
NRZ
cod
e
wh
ich ha
s be
en
use
d
for long
time into RZ or othe
r more
efficient cod
e
s [11-12].
Long
distance
tran
sm
issi
on
expe
ri
ment
re
sults
has
sho
w
n t
hat, includi
ng
data like th
e
lowe
st tolerat
ed OSNR a
nd tolerance
of disp
e
r
sion,
N×4
0
G
DWDM sy
stem that is ba
sed
on
modulatin
g a
nd coding te
chn
o
logy such as
DRZ
is mature a
nd
able to me
et the dema
n
d
of
busi
n
e
ss req
u
irem
ents.
Referen
ces
[1]
XU
Xi
ao
gen
g, Z
H
ANG Xin
lia
n
g
, LIU Deming,
et
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e
rime
ntal Stud
y on T
r
ansmissi
on P
e
rformanc
e
of
T
h
ree Diffe
rent F
o
rmats in 40Gb/
s Optical F
i
ber Com
m
unic
a
tion S
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Chines
e
Journa
l of
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. 20
05;1
0
(32): 13
71-
13
76.
[2]
X
IONG Bo, Chen Yongz
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r
ansmission
performa
nce r
e
searc
h
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R
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r
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u
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c
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Ho
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N
B
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yi
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UN
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Verific
a
tion
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e
Measur
emen
t
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a
ch
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nd OSN
R
Onlin
e
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ang, S C
h
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-
T
b
/s single-ch
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el c
o
h
e
rent
optic
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DM
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w
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u
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r 40/10
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ANG F
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A
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turn-to-ze
r
o
differenti
a
l
ph
a
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dul
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r ra
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