474
11 Basics of Optical Amplifiers
−4.85 dBm + (7.1 + 0.375) dB = 2.63 dBm
which is within 0.37 dB of the normal +3 dBm level.
11.10 (a) For N input signals, the output signal level is given by
P s,out = G
N
i=1
P s,in (i) ≤ 1 mW.
The inputs are 1 μW (−30 dBm) each and the gain is 26 dB (a factor of 400).
Thus for one input signal, the output is (400)(1 μW) = 400 μW or −4 dBm.
For two input signals, the total output is 800 μW or −1 dBm. Thus the level
of each individual output signal is 400 μW or −4 dBm.
For four input signals, the total input level is 4 μW or −24 Bm. The output
then reaches its limit of 0 dBm, because the maximum gain is 26 dB. Thus
the level of each individual output signal is 250 μW or −6 dBm.
Similarly, for eight input channels the maximum output level is 0 dBm, so the
level of each individual output signal is 1/8(1 mW) = 125 μW or −9 dBm.
(b) When the pump power is doubled, the outputs for one and two inputs
remain at the same level. However, for four inputs, the individual output
level is 500 μW or −3 dBm, and for 8 inputs, the individual output level is
250 μW or −6 dBm.
References
1. D.R. Zimmerman, L.H. Spiekman, Amplifiers for the masses: EDFA, EDWA, and SOA amplets
for metro and access applications. J. Lightw. Technol. 22, 63–70 (2004)
2. R.E. Hunsperger, Optical amplifiers, chap. 13, in Integrated Optics, Springer, 6th edn. (2009),
pp. 259–275
3. V. Ter-Mikirtychev, Fundamentals of Fiber Lasers and Fiber Amplifiers (Springer, 2014)
4. S. Singh, R.S. Kaler, Review on recent developments in hybrid optical amplifier for dense
wavelength division multiplexed system. Opt. Eng. 54, 100901(1–11) (2015)
5. M. Singh, A review on hybrid optical amplifiers. J. Opt. Commun. 39(3), 267–272 (2018)
6. N.K. Dutta, Q. Wang, Semiconductor Optical Amplifiers, 2nd edn. (World Scientific, 2013)
7. B.L. Anderson, R.L. Anderson, Fundamentals of Semiconductor Devices, 2nd edn. (McGrawHill, 2018)
8. W. Miniscalco, Erbium-doped glasses for fiber amplifiers at 1500 nm. J. Lightw. Technol. 9,
234–250 (1991)
9. P.C. Becker, N.A. Olsson, J.R. Simpson, Erbium-Doped Fiber Amplifiers (Academic Press,
1999)
10. E. Desurvire, Erbium-Doped Fiber Amplifiers: Principles and Applications (Wiley, New York,
2002)
11. E. Desurvire, D. Bayart, B. Desthieux, S. Bigo, Erbium-Doped Fiber Amplifiers: Devices and
System Developments (Wiley, New York, 2002)
12. G.R. Khan, An analytical method for gain in erbium-doped fiber amplifier with pump excited
state absorption. Opt. Fiber Technol. 18(6), 421–424 (2012)
11 Basics of Optical Amplifiers
−4.85 dBm + (7.1 + 0.375) dB = 2.63 dBm
which is within 0.37 dB of the normal +3 dBm level.
11.10 (a) For N input signals, the output signal level is given by
P s,out = G
N
i=1
P s,in (i) ≤ 1 mW.
The inputs are 1 μW (−30 dBm) each and the gain is 26 dB (a factor of 400).
Thus for one input signal, the output is (400)(1 μW) = 400 μW or −4 dBm.
For two input signals, the total output is 800 μW or −1 dBm. Thus the level
of each individual output signal is 400 μW or −4 dBm.
For four input signals, the total input level is 4 μW or −24 Bm. The output
then reaches its limit of 0 dBm, because the maximum gain is 26 dB. Thus
the level of each individual output signal is 250 μW or −6 dBm.
Similarly, for eight input channels the maximum output level is 0 dBm, so the
level of each individual output signal is 1/8(1 mW) = 125 μW or −9 dBm.
(b) When the pump power is doubled, the outputs for one and two inputs
remain at the same level. However, for four inputs, the individual output
level is 500 μW or −3 dBm, and for 8 inputs, the individual output level is
250 μW or −6 dBm.
References
1. D.R. Zimmerman, L.H. Spiekman, Amplifiers for the masses: EDFA, EDWA, and SOA amplets
for metro and access applications. J. Lightw. Technol. 22, 63–70 (2004)
2. R.E. Hunsperger, Optical amplifiers, chap. 13, in Integrated Optics, Springer, 6th edn. (2009),
pp. 259–275
3. V. Ter-Mikirtychev, Fundamentals of Fiber Lasers and Fiber Amplifiers (Springer, 2014)
4. S. Singh, R.S. Kaler, Review on recent developments in hybrid optical amplifier for dense
wavelength division multiplexed system. Opt. Eng. 54, 100901(1–11) (2015)
5. M. Singh, A review on hybrid optical amplifiers. J. Opt. Commun. 39(3), 267–272 (2018)
6. N.K. Dutta, Q. Wang, Semiconductor Optical Amplifiers, 2nd edn. (World Scientific, 2013)
7. B.L. Anderson, R.L. Anderson, Fundamentals of Semiconductor Devices, 2nd edn. (McGrawHill, 2018)
8. W. Miniscalco, Erbium-doped glasses for fiber amplifiers at 1500 nm. J. Lightw. Technol. 9,
234–250 (1991)
9. P.C. Becker, N.A. Olsson, J.R. Simpson, Erbium-Doped Fiber Amplifiers (Academic Press,
1999)
10. E. Desurvire, Erbium-Doped Fiber Amplifiers: Principles and Applications (Wiley, New York,
2002)
11. E. Desurvire, D. Bayart, B. Desthieux, S. Bigo, Erbium-Doped Fiber Amplifiers: Devices and
System Developments (Wiley, New York, 2002)
12. G.R. Khan, An analytical method for gain in erbium-doped fiber amplifier with pump excited
state absorption. Opt. Fiber Technol. 18(6), 421–424 (2012)