Preform Specifications

Item Requirements Remark 1 Average Preform Diameter (O.D.) 135 ~ 160 mm (Note 1.1) 2 Maximum Preform Diameter (ODmax) ≤ 160 mm 3 Minimum Preform Diameter (ODmin) ≥ 130 mm 4 Tolerance of O.D. (within a Preform) ≤ 20 mm ( in straight part ) 5 Preform Length (including handle part) 2600 ~ 3600 mm (Note 1.2) 6 Effective length ≥ 1800 mm 7 Taper length ≤ 250 mm 8 Diameter at the end of taper ≤ 30 9 Preform Non-circularity ≤ 1 % 10 Concentricity Error ≤ 0.5 μm 11 Appearance (Note 1.4&1.5)

Note 1.1:  The preform diameter shall be measured continuously in straight part with 10mm interval by the Laser Diameter Measurement System and to be defined as the average of measured values. Taper part shall be defined as the position between A to B. Straight Part shall be defined as the position between B to C. A is the position at end of preform. B is the start position having effective core. C is the end position having effective core. D is the end side of preform.

Note 1.2:  “ Preform Length” shall be defined as shown in the Figure 1.1.

Note 1.3:  Effective Part shall be defined as the position between B to C.

Chargeable Length = Effective Length -  ∑Unusable Length at Defect (LUD)

Location and Size of Bubble

Number / 1,000 cm3

Core Region (=core + inner cladding)

(See Note 1.5)

Outer Cladding Region

(=interface + outer cladding)

~ 0.5 mm

No Count

0.5 ~ 1.0 mm

≤ 10

1.0 ~ 1.5 mm

≤ 2

1.5 ~ 2.0 mm

≤ 1.0

2.1 mm ~

(See Note 1.5)

Target Fiber Characteristics

When the drawing conditions and the measurement conditions are optimum and stable, the preforms shall be expected to meet the target fiber specifications as shown in Table 2.1.

	Item	Requirements
1	Attenuation at 1310 nm	≤ 0.34 dB/km
	Attenuation at 1383 nm	≤ 0.34 dB/km	(Note 2.1)
	Attenuation at 1550 nm	≤ 0.20 dB/km
	Attenuation at 1625 nm	≤ 0.23 dB/km
	Uniformity of Attenuation	≤ 0.05 dB/km at 1310&1550 nm
2	Mode Field Diameter at 1310 nm	9.1± 0.4 µm
3	Cable Cutoff Wavelength (λcc)	≤ 1260 nm
4	Zero Dispersion Wavelength (λ0)	1300 ~ 1324 nm
5	Dispersion at 1285~1340 nm	-3.8 ~ 3.5 ps/(nm·km)
6	Dispersion 1550 nm	13.3 ~ 18.6 ps/(nm·km)
7	Dispersion 1625 nm	17.2 ~ 23.7 ps/(nm·km)
8	Dispersion Slope at λ0	0.073 ~ 0.092 ps/(nm2·km)
9	Core Concentricity Error	≤ 0.6 µm

Note 2.1: The attenuation at 1383 nm after hydrogen aging test shall not be included in the Table 2.1 because it highly depends on the fiber drawing conditions.