The optical fiber communication band around 1530 to 1565 nm. Silica fiber loss is lowest there (about 0.2 dB/km) and erbium-doped fiber amplifiers (EDFAs) can amplify it, so it is used for long-haul links and dense wavelength division multiplexing (DWDM).
Japanese name: Cバンド
C-band appears in 4 practice questions across 1 topic, including Silicon photonics.
Field: Silicon photonics
Answer: A. It is the band where loss in silica optical fiber is lowest
Loss in silica (SiO2) fiber increases from Rayleigh scattering at short wavelengths and from infrared absorption at long wavelengths, so it is lowest in between, around 1.55 µm (about 0.2 dB/km). Even after 100 km the loss is only about 20 dB, and the ability to amplify the light directly in the optical domain with erbium-doped fiber amplifiers (EDFAs) is another reason the C-band is used for long-haul communication. In standard single-mode fiber, chromatic dispersion is nearly zero around 1.31 µm (O-band); dispersion remains at 1.55 µm. Silicon barely absorbs this wavelength.
Answer: C. About 0.8 nm
Δλ ≈ (1.55×10⁻⁶ m)² × 100×10⁹ Hz ÷ (3×10⁸ m/s) ≈ 0.8×10⁻⁹ m, or about 0.8 nm. In DWDM (dense wavelength division multiplexing), used for long-haul, high-capacity communication, dozens of wavelengths are placed on the frequency grid defined by ITU-T at spacings such as 100 GHz (about 0.8 nm) or 50 GHz (about 0.4 nm). Because the spacing is narrow, laser wavelengths must be precisely stabilized by temperature control or similar means. Since optical frequency and wavelength are inversely proportional, when the spacing is set in frequency, the wavelength spacing becomes slightly narrower at shorter wavelengths.
Even after 100 km the loss is only about 20 dB, and the ability to amplify the light directly in the optical domain with erbium-doped fiber amplifiers (EDFAs) is another reason the C-band is used for long-haul communication.
In long-haul optical fiber communication, what is the main …Because it does not rely on diffraction, its wavelength dependence is small, making it easy to obtain low loss of about 1–2 dB or less over a wide band spanning the O-band and C-band, and it also handles different polarizations more easily.
Which correctly describes an edge coupler, which couples to…Silicon's refractive index changes strongly with temperature (thermo-optic coefficient about 1.8×10⁻⁴ /K), so the resonant wavelength of a C-band ring resonator shifts toward longer wavelengths by about 0.07–0.08 nm per 1 °C.
Why do optical circuits using ring resonators often place a…As an Amazon Associate I earn from qualifying purchases.
O-band Waveguide Single-mode fiber Chromatic dispersion WDM (wavelength division multiplexing) Edge coupler Grating coupler Dicing Refractive index Ring resonator