Power Budget Calculations For Ml810 Modules With Fiber Media - GE Multilink ML810 Instruction Manual

CHAPTER 4: OPERATION
MULTILINK ML810 MANAGED EDGE SWITCH – INSTRUCTION MANUAL

POWER BUDGET CALCULATIONS FOR ML810 MODULES WITH FIBER MEDIA

4.4 Power Budget Calculations for ML810 Modules 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
Multilin products, the following equations should be used:
OPB (Optical Power Budget) = P
where P = Transmitter Output Power, and P
T
Worst case OPB = OPB - 1dBm(for LED aging) - 1dBm(for insertion loss)
Worst case distance = {Worst case OPB, in dBm} / [Cable Loss, in dBm/Km]
where the "Cable Loss" for 62.5/125 and 50/125μm (M.m) is 2.8 dBm/km,
and the "Cable Loss" for 100/140 (Multi-mode, 850 nm) is 3.3 dBm/km,
and the "Cable Loss" for 9/125 (Single-mode, 1310 nm) is 0.5 dBm/km (a worst case
industry number)
and the "Cable Loss" for 9/125 (Single-mode, 1310 nm) is 0.4 dBm/km (H4)
and the "Cable Loss" for 9/125 (Single-mode,1550 nm) is 0.25 dBm/km (H5)
and the "Cable Loss" for 9/125 (Single-mode, 1550 nm) is 0.2 dBm/km (H6)
The use of either multi-mode or single-mode fiber to operate at 100 Mbps or Gb speed
over long distances (i.e., over approx. 400 meters) can be achieved only if the following
factors are both applied:
• The fiber segment must operate in full-duplex (FDX) mode
• The worst-case OPB of the fiber link must be greater than the fiber cable's passive
Attenuation. (Attenuation = Cable loss + LED aging loss + Insertion loss + safety
factor).
(min) - P (min)
T R
= Receiver Sensitivity
R
4–5