# Quiz 1 answers - 5. The power into an optical amplifier is...

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Quiz 1 Answers 1. What is -7dBm in mW? P = 10 (-7/10) = 0.2mW 2. What is 40mW in dBm? P = 10log 10 (40) = 16dBm 3. The input power to a 5km fibre is 20mW. The fibre loss is 0.4dB/km. What is the output power in mW? Pin = 10log 10 (20) = 13dBm Total Loss = 0.4dB/km x 5km = 2dB Pout = Pin – Total Loss = 11dBm Pout (mW) = 10 (11/10) = 12.6mW (1dp) 4. An optical signal passes into an ideal 50/50 fibre optic power splitter. What is the loss in dB when you examine one of the output ports? Half (50%) of the power is lost to the other port so the linear loss is 0.5. So the change in power is = 10log10(0.5) = -3dB So we would say there was a 3dB loss.

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Unformatted text preview: 5. The power into an optical amplifier is 5mW. The gain of the amplifier is 23dB and the saturation output power is 33dBm. What would the amplifiers output power be in mW? Pin = 10log10(5) = 7dBm Pout = Pin + gain = 7 + 23 = 30dBm Pout (mW) = 10 (30/10) = 1000mW = 1W 6. The input power is increased to 20mW what would the new output power be? Pin = 10log10(20) = 13dBm Pout = Pin + gain = 13 + 23 = 36dBm But because this is above the amplifiers saturation output power the amplifier will be in saturation. Therefore the output power will be limited to the saturation output power of 33dBm or 2W....
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## This note was uploaded on 03/23/2011 for the course EEE 174 taught by Professor Kasab during the Spring '11 term at ASU.

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Quiz 1 answers - 5. The power into an optical amplifier is...

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