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CHAPTER 4: OPERATION OPERATION
MULTILINK ML2400 ETHERNET COMMUNICATIONS SWITCH – INSTRUCTION MANUAL 4–5
4.1.8 Power Budget Calculations with Fiber Media
Receiver sensitivity and transmitter power are the parameters necessary to compute the
power budget. To calculate the power budget of different fiber media installations using
MultiLink products, the following equations should be used:
(EQ 4.1)
where: OPB = optical power budget
P
T
= transmitter output power
P
R
= Receiver Sensitivity
The worst case OPB is as follows:
(EQ 4.2)
The worst-case distance is calculated as follows:
(EQ 4.3)
The cable loss in dB/km is defined in the following table:
The following data has been collected to provide guidance to network designers and
installers.
Table 4–1: Cable losses
Cable size Mode Cable loss
62.5 / 125 μmmulti-mode 2.8 dB/km
50 / 125 μmmulti-mode 2.8 dB/km
100 / 140 μmmulti-mode 3.3 dB/km
9 / 125 μm single-mode 0.5 dB/km
0.4 dB/km (LXSC25)
0.25 dB/km (LXSC40)
0.2 dB/km (LXSC70)
OPB P
tmin()
P
Rmin()
–=
OPB
worst
OPB 1dB (LED aging)– 1dB (insertion loss)–=
distance
worst
worst-case OPB (in dB)
cable loss (in dB/km)
--------------------------------------------------------=
Table 4–2: Power budget values for various modules
Module Speed Mode fdx (hdx) λ Size P
T
P
R
OPB
worst
d
worst
OPB
typ
d
typical
A1, A5 10 Mb FL multi 2 (2) km 850 nm 62.5/125 μm
100/140 μm
50/125 μm
-15.0 dB
-9.5 dB
-19.5 dB
-31 dB
-31 dB
-31 dB
14 dB
19.5 dB
19.5 dB
5.0 km
5.9 km
3.4 km
17 dB
23.5 dB
13.2 dB
6.0 km
7.0 km
4.8 km
A2, A3, A6 100 Mb FX multi 2 (0.4) km 1300 nm 62.5/125 μm
50/125 μm
-20 dB-
23.5 dB
-31 dB
-31 dB
9.0 dB
5.5 dB
3.0 km
2.0 km
14 dB
12 dB
5.0 km
4.0 km
A7, A8 100 Mb FX single 18+ (0.4) km 1300 nm 9/125 μm -15dB -31dB 14dB 28km 17.5dB 35km
AA, AB 100 Mb FX multi 2 (0.4) km 1310 nm 62.5/125 μm -19 dB -31 dB 12 dB 4.0 km 16 dB 5.7 km
AC, AD, AE 100 Mb FX single 15+ km 1310 nm 9/125 μm -15dB -28dB 11dB 22km -- --
AF 10 Mb FL multi 2 (2) km 850 nm 62.5/125 μm
100/140 μm
50/125 μm
-15.0 dB
-9.5 dB
-19.5 dB
-31 dB
-31 dB
-31 dB
14 dB
19.5 dB
9.5 dB
5.0 km
5.9 km
3.4 km
17 dB
23.5 dB
13.5 dB
6.0 km
7.0 km
4.8 km
AG 100 Mb FX single 18+ (0.4) km 1310 nm 9/125 μm -20dB -31dB 9.0dB 18km 12.5dB 25km
G7 1000 Mb multi 0.55 km 1310 nm 62.5/125 μm
50/125 μm
-9.5dB -17dB 5.5dB 2km 12.5dB 4km
G8 1000 Mb FX single 10 km 1310 nm 9/125 μm -9.5dB -20dB 8.5dB 17km 10.5dB 21km
G9, GM 1000 Mb FX single 25 km 1310 nm 9/125 μm -4.0 dB -21 dB 15 dB 38 km 17.5 dB 43 km
GA 1000 Mb FX single 40 km 1310 nm 9/125 μm -4.0 dB -21 dB 15 dB 60 km 17.5 dB 70 km
GB 1000 Mb FX single 70 km 1310 nm 9/125 μm -3.0 dB -23 dB 18 dB 90 km 20.5 dB 102 km