Optical fiber Standards

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According to ITU-T, three types of single-mode optical fibers are defined in G.652, G.653, and G.655 respectively. The differences between them are shown in the following table:

Type Definition Scope Main Specifications

G.652

The standard single-mode fiber (SMF) refers to the fiber whose zero-dispersion point (the zero-dispersion wavelength) is near to 1310 nm.

Used in both SDH system and DWDM system

Attenuation: The attenuation value of the 1310 nm band is 0.3–0.4 dB/km and the typical value is 0.35 dB/km. The attenuation value of the 1550 nm band is 0.17–0.25 dB/km and the typical value is 0.20 dB/km.Dispersion: The allowed value of the zero-dispersion wavelength is 1300–1324 nm. The dispersion coefficient of the 1550 nm band is positive and the typical value of the dispersion coefficient D is 17 ps/(nm.km). The maximum value is not more than 20 ps/(nm.km).

G.653

Dispersion-shifted fiber (DSF) refers to the fiber whose zero-dispersion point is near to 1550 nm. Compared with G.652 SMF, the zero-dispersion point of G.653 DSF shifts.

Used in the SDH system but not in the DWDM system

Attenuation: The attenuation value of the 1310 nm band is less than 0.55 dB/km and the typical value has not been confirmed. The attenuation value of the 1550 nm band is less than 0.35 dB/km and the typical value is 0.19–0.25 dB/km.Dispersion: The wavelengths in the G.653 DSF are near to 1550 nm, usually 1525–1575 nm. The maximum dispersion coefficient is 3.5 ps/(nm.km). The dispersion coefficient in the DSF is too small or may be 0 for 1550 nm bands, especially C band.

G.655

Non-zero dispersion-shifted fiber (NZDSF) refers to the fiber whose zero-dispersion point is shifted away from 1550 nm and not within the DWDM operating wavelength range near to 1550 nm.

Used in both SDH system and DWDM system, but more applicable to the DWDM system

Attenuation: The attenuation value of the 1310 nm band is not specified in ITU-T. The attenuation value of the 1550 nm band is less than 0.35 dB/km, usually 0.19–0.25 dB/km.Dispersion: If 1530 nm < < 1565 nm, 0.1 ps/(nm.km) < |D(λ)| < 6.0 ps/(nm.km). The typical value of the dispersion coefficient of the G.655 NZDSF varies with vendors and needs to be confirmed based on actual situations, usually 4.5 ps/(nm.km) and 6 ps/(nm.km).

G.652/G.653/G.655 Single-Mode Optical FibersG.652/G.653/G.655 Single-Mode Optical Fibers

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Characteristics of G.652/G.653/G.655 FibersCharacteristics of G.652/G.653/G.655 Fibers

Dispersion coefficient ps/(nm·km)

Positive dispersion coefficient of G.655 NZDSF

Wavelength (nm)15501310

17

1.The minimum dispersion and attenuation in the 1550 nm band, applicable to the DWDM system and able to transmit signals at a high speed.2.Applications: TrueWave fibers (SPM effects in the positive dispersion area facilitate transmission) and LEAF-large effective area fibers (non-linear effects are weakened)

G.652 SMF: large-scale laying, high-speed transmission and dispersion compensation

G.653 DSF: serious frequency mixture in the 1550 nm band and not applicable to the DWDM system

Negative dispersion coefficient of G.655 NZDSF

G.654Similar to G.653 DSF but different in cut-off wavelengths. The cut-off wavelength in G.654 fiber is 1530 nm.

Full wavelength fiber

Eliminating the "water peak" gain at 1380 nm.