Itu-t rec. G. 957 (06/99) Optical interfaces for equipments and systems relating to the synchronous digital hierarchy

A.1 Operating wavelength ranges determined by fibre attenuation

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T-REC-G.957-199907-S!!PDF-E
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Figure A.1/G.957 – Typical spectral attenuation coefficient for the installed fibre cable between S and R

A.1
Operating wavelength ranges determined by fibre attenuation
The general form of attenuation coefficient for installed fibre cable used in this Recommendation is
shown in Figure A.1. Included here are losses due to installation splices, repair splices, and the
operating temperature range. Recommendation G.652 states that attenuation values in the range
0.3-0.4 dB/km in the 1310 nm region and 0.15-0.25 dB/km in the 1550 nm region have been
obtained.
The wavelength ranges indicated in Tables 2 to 4 have been confirmed by data from fibre
manufacturers combined with assumptions for a total margin to account for cabling, installation
splicing, repair splicing and temperature operating range. Therefore, the following reference
maximum attenuation coefficient values are considered appropriate only for systems calculations:
3.5 dB/km in case of intra-office, 0.8 dB/km in case of short-haul, 0.5 dB/km in case of 1310 nm
long-haul and 0.3 dB/km in case of 1550 nm long-haul applications. By using these attenuation
coefficient values, it is indicated that the approximate target distances in Table 1 are achievable.

Recommendation G.957 (06/99)
18
0
1
2
3
1200
1300
1400
1500
1600
1260
1280
1335
1360
1430
1480
1580
A
C
D
B
T1509000-92
nm
dB/km
Wavelength
A
tte
nua
ti
on co
ef
fi
ci
en
t
Ranges A and B are suitable for long-haul (L-N.x) applications, and
ranges C and D are suitable for short-haul (S-N.x) and intra-office (I-N)
applications.
Figure A.1/G.957 – Typical spectral attenuation coefficient
for the installed fibre cable between S and R

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