24
1 Perspectives on Lightwave Communications
1980
1985
1990
1995
2000
2005
2010
2015
Year
Bit rate (b/s)
10M
100M
1G
10G
1T
100G
45 Mb/s
20 km
155 Mb/s
20 km
622 Mb/s
80 km
2.5 Gb/s
400 km
10 Gb/s
1000 km
40 Gb/s
1000 km
DPSK
100 Gb/s
1000 km
DP-QPSK
400 Gb/s
to 1Tb/s
MQAM
On-off keying (OOK)
modulaon
Single wavelength
WDM
Advanced
modulaon
2020
10 Tb/s
MQAM
10T
Fig. 1.12 Evolution in optical communication network capacities
about 1995, an optical fiber typically carried data on a single wavelength using OOK
modulation. Progressively higher data transmission rates were achieved mainly by
developing more efficient data routing and switching equipment and taking advantage
of improvements in silicon device technology for laser drivers. Then in the mid-1990s
the use of wavelength division multiplexing (WDM) allowed a significant increase
in link capacity by sending information on several wavelengths simultaneously over
an individual optical fiber. In addition, the development and deployment of optical
amplifiers enabled carriers to send information over longer distances without the
need for intermediate repeater stations.
Initially, to send data the telecom companies (carriers) used simple OOK modulation at the transmitter and direct detection schemes at the receiver. This changed
starting in 2005 with the introduction of advanced modulation techniques to increase
spectral efficiency, coherent detection to enable multilevel demodulation, sophisticated digital signal processing (DSP) to compensate for optical signal impairment,
and forward error correction (FEC) processing to reduce signal-to-noise ratio requirements. Differential phase-shift keying (DPSK) modulation schemes introduced in
2005 allowed transmissions at 40 Gb/s per wavelength. Dual polarization quadrature phase-shift keying (DP-QPSK) modulation with a coherent receiver started being
implemented in 2011 for 100 Gb/s per wavelength transmission. The next step starting
in 2017 was to use higher-order modulation techniques, such as 16QAM and 64QAM
(quadrature amplitude modulation), to achieve from 400 Gb/s to 10 Tb/s and beyond
[36–39] (see Chap. 13 for more details on these techniques).
1 Perspectives on Lightwave Communications
1980
1985
1990
1995
2000
2005
2010
2015
Year
Bit rate (b/s)
10M
100M
1G
10G
1T
100G
45 Mb/s
20 km
155 Mb/s
20 km
622 Mb/s
80 km
2.5 Gb/s
400 km
10 Gb/s
1000 km
40 Gb/s
1000 km
DPSK
100 Gb/s
1000 km
DP-QPSK
400 Gb/s
to 1Tb/s
MQAM
On-off keying (OOK)
modulaon
Single wavelength
WDM
Advanced
modulaon
2020
10 Tb/s
MQAM
10T
Fig. 1.12 Evolution in optical communication network capacities
about 1995, an optical fiber typically carried data on a single wavelength using OOK
modulation. Progressively higher data transmission rates were achieved mainly by
developing more efficient data routing and switching equipment and taking advantage
of improvements in silicon device technology for laser drivers. Then in the mid-1990s
the use of wavelength division multiplexing (WDM) allowed a significant increase
in link capacity by sending information on several wavelengths simultaneously over
an individual optical fiber. In addition, the development and deployment of optical
amplifiers enabled carriers to send information over longer distances without the
need for intermediate repeater stations.
Initially, to send data the telecom companies (carriers) used simple OOK modulation at the transmitter and direct detection schemes at the receiver. This changed
starting in 2005 with the introduction of advanced modulation techniques to increase
spectral efficiency, coherent detection to enable multilevel demodulation, sophisticated digital signal processing (DSP) to compensate for optical signal impairment,
and forward error correction (FEC) processing to reduce signal-to-noise ratio requirements. Differential phase-shift keying (DPSK) modulation schemes introduced in
2005 allowed transmissions at 40 Gb/s per wavelength. Dual polarization quadrature phase-shift keying (DP-QPSK) modulation with a coherent receiver started being
implemented in 2011 for 100 Gb/s per wavelength transmission. The next step starting
in 2017 was to use higher-order modulation techniques, such as 16QAM and 64QAM
(quadrature amplitude modulation), to achieve from 400 Gb/s to 10 Tb/s and beyond
[36–39] (see Chap. 13 for more details on these techniques).