GarrettCom Quad manual Fiber Port Module

Magnum Quad-Series Fiber Switches Installation and User Guide (06/03)

4.7Power Budget Calculations for Quad-Series QPM’s 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 Magnum products, the following equations should be used:

OPB (Optical Power Budget) = PT(min) - PR(min)

where PT = Transmitter Output Power, and PR = Receiver Sensitivity

Worst case OPB = OPB - 1dB(for LED aging) - 1dB(for insertion loss) Worst case distance = {Worst case OPB, in dB} / [Cable Loss, in dB/Km]

where the “Cable Loss” for 62.5/125 and 50/125∝m (M.m) is 2.8 dB/km, and the “Cable Loss” for 100/140 (Multi-mode) is 3.3 dB/km,

and the “Cable Loss” for 9/125 (Single-mode) is 0.5 dB/km

The following data has been collected from component manufacturer’s (Agilent’s and Siemens’) web sites and catalogs to provide guidance to network designers and installers.

Fiber

Port

Module

QPM10-

FST

QPM-

MST, MSC

QPM-SSC

QPM-

MTRJ

QPM-

MV45

Speed,		Std.	Wave	Cable	X’mitr	R’cvr	Worst	Worst*	typical	typical*
Std.	Mode	km	-	Size	Output	Sens.	OPB,	distance	OPB,	distance
		fdx	length	∝m	PT , dB	PR ,dB	dB	Km, fdx	dB	Km, fdx
		(hdx)	nm
10 Mb	Multi-	2		62.5/125	-15.0	-31	14	5	17	6
			850	100/140	-9.5	-31	19.5	5.9	23.5	7
FL	mode	(2)
				50/125	-19.5	-31	9.5	3.4	13.5	4.8
100Mb	Multi-	2	1300	62.5/125	-20	-31	9.0	2.5	14	5
FX	mode	(0.4)		50/125	-23.5	-31	5.5	2.0	12	4
100Mb	Single-	18+	1300	9/125	-15	-31	14	28	17.5	35
FX	mode	(0.4)
100Mb	Multi-	2	1300	62.5/125	-20	-31	9.0	3.0	15.8	5.5
FX	mode	(0.4)		50/125	-23.5	-31	5.5	2.0	12.2	4.0
100Mb	Multi-	2	1300	62.5/125	-14	-31	15	5	16	5.7
FX	mode	(0.4)

*Note: The use of either multi-mode or single-mode fiber to operate at 100Mbps speed over long distances (i.e., in excess of approx. 400 meters) can be achieved only if the following factors are both applied:

•The 100Mb fiber segment must operate in full-duplex (FDX) mode, i.e. the full-duplex (factory default) setting for 100Mbps fiber ports must be used, and

•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)

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