Calculating the Power Budget for Fiber-Optic Cable for the SRX1400 Services Gateway

To ensure that fiber-optic connections have sufficient power for correct operation, you need to calculate the link's power budget, which is the maximum amount of power it can transmit. When you calculate the power budget, you use a worst-case analysis to provide a margin of error, even though all the parts of an actual system do not operate at the worst-case levels. To calculate the worst-case estimate of power budget (P_B), you assume minimum transmitter power (P_T) and minimum receiver sensitivity (P_R):

P_B = P_T – P_R

The following hypothetical power budget equation uses values measured in decibels (dB) and decibels referred to one milliwatt (dBm):

P_B = P_T – P_R

P_B = –15 dBm – (–28 dBm)

P_B = 13 dB

Related Documentation

• SRX1400 Services Gateway Electrical Wiring Guidelines
• Signal Loss in Multimode and Single-Mode Fiber-Optic Cable for the SRX1400 Services Gateway
• Attenuation and Dispersion in Fiber-Optic Cable for the SRX1400 Services Gateway
• Calculating the Power Margin for Fiber-Optic Cable for the SRX1400 Services Gateway