1.2 Optical Wavelength Bands
7
Solution Using Eq. (1.3) yields E(850 nm) = 1.46 eV, E(1310 nm) = 0.95 eV, and
E(1550 nm) = 0.80 eV.
Figure 1.2 shows the optical spectrum ranges from about 5 nm in the ultraviolet
region to 1 mm for far-infrared radiation. In between these limits is the 400-to700 nm visible band. Optical fiber communication uses the near-infrared spectral
band ranging from nominally 770–1675 nm.
The Telecomunications Sector of The International Telecommunications Union
(ITU-T) has designated six spectral bands for use in optical fiber communications
within the 1260-to-1675 nm region [24]. These long-wavelength band designations arose from the attenuation characteristics of optical fibers and the performance
behavior of an erbium-doped fiber amplifier (EDFA), as described in Chaps. 3 and
10, respectively. Figure 1.3 shows and Table 1.1 defines the regions and the origins
of their designations, which are known by the letters O, E, S, C, L, and U.
Traditionally fiber optic telecommunications organizations expressed interest in
transmitting high-capacity information over long distances. Thus the emphasis was
O-Band
E-Band
S-Band
C-Band
L-Band
U-Band
1260
1360
1460
1530 1565
1625
1675
Wavelength (nm)
238
220
238
193
179
T-Band
1000
300
Optical frequency (THz)
Defined by ITU-T
Proposed by NICT Japan
1550 nm/193 THz: widely used
Fig. 1.3 Designations of spectral bands used for optical fiber communications
Table 1.1 Spectral band designations used in optical fiber communications
Name
Designation Spectrum (nm) Origin of name
Thousand band
T-band
1000–1260
Thousands of potential additional
transmission channels
Original band
O-band
1260–1360
Original region used for single-mode fiber
links
Extended band
E-band
1360–1460
Link use can extend into the region for fibers
with low water content
Short band
S-band
1460–1530
Wavelengths are shorter than the C-band but
higher than the E-band
Conventional band C-band
1530–1565
Wavelength region used by EDFAs
Long band
L-band
1565–1625
Gain of an EDFA decreases steadily to 1 at
1625 nm in this band
Ultra-long band
U-band
1625–1675
Region beyond the response capability of an
EDFA
7
Solution Using Eq. (1.3) yields E(850 nm) = 1.46 eV, E(1310 nm) = 0.95 eV, and
E(1550 nm) = 0.80 eV.
Figure 1.2 shows the optical spectrum ranges from about 5 nm in the ultraviolet
region to 1 mm for far-infrared radiation. In between these limits is the 400-to700 nm visible band. Optical fiber communication uses the near-infrared spectral
band ranging from nominally 770–1675 nm.
The Telecomunications Sector of The International Telecommunications Union
(ITU-T) has designated six spectral bands for use in optical fiber communications
within the 1260-to-1675 nm region [24]. These long-wavelength band designations arose from the attenuation characteristics of optical fibers and the performance
behavior of an erbium-doped fiber amplifier (EDFA), as described in Chaps. 3 and
10, respectively. Figure 1.3 shows and Table 1.1 defines the regions and the origins
of their designations, which are known by the letters O, E, S, C, L, and U.
Traditionally fiber optic telecommunications organizations expressed interest in
transmitting high-capacity information over long distances. Thus the emphasis was
O-Band
E-Band
S-Band
C-Band
L-Band
U-Band
1260
1360
1460
1530 1565
1625
1675
Wavelength (nm)
238
220
238
193
179
T-Band
1000
300
Optical frequency (THz)
Defined by ITU-T
Proposed by NICT Japan
1550 nm/193 THz: widely used
Fig. 1.3 Designations of spectral bands used for optical fiber communications
Table 1.1 Spectral band designations used in optical fiber communications
Name
Designation Spectrum (nm) Origin of name
Thousand band
T-band
1000–1260
Thousands of potential additional
transmission channels
Original band
O-band
1260–1360
Original region used for single-mode fiber
links
Extended band
E-band
1360–1460
Link use can extend into the region for fibers
with low water content
Short band
S-band
1460–1530
Wavelengths are shorter than the C-band but
higher than the E-band
Conventional band C-band
1530–1565
Wavelength region used by EDFAs
Long band
L-band
1565–1625
Gain of an EDFA decreases steadily to 1 at
1625 nm in this band
Ultra-long band
U-band
1625–1675
Region beyond the response capability of an
EDFA