Few-mode Fibre (FMF)

General Details

The MDM transmission system uses the limited orthogonal modes in few mode fibre (FMF) as the independent channels to carry out information transmission in order to multiply the transmission capacity of the system. The few mode optical fibre uses different modes in the fibre as a new degree of freedom, and the spectrum efficiency of the system can be improved successfully by FMF. As FMF has large mode field areas, its nonlinear tolerance is always better than that of SMF. It not only improves the capacity of the optical transmission system but also avoids the nonlinear effects. The MDM system based on FMF can solve the future single-mode fibre bandwidth crisis. The FMFs take advantage of PCVD process which is able to manufacture complex index-profile accurately, it can get various types of core layer structure, such as Step-Index, Graded-Index etc. According to different design, 2-mode, 4-mode, 6-mode, 9-mode FMFs and even Ultra-low-loss (ULL) FMFs can be realized.

Features
  • Strictly controlled optical and geometrical parameters
  • Customized waveguide is available
  • Low macro-bending loss
  • Low DMD for graded index fibre
  • High DMD for step index fibre
Specifications

Specifications of Two Mode Fibre (Graded-Index)

Fibre Type FM GI-2
Part No. FM2010-A
Optical Characteristics@1550nm Range Typical Value
Core Diameter (μm) 20±0.3
Cladding Diameter (μm) 125±0.5
Cladding Non-circularity (%) < 0.7
Wavelength (nm) 1450-1700
Coating Diameter (μm) 245±10
Dispersion (ps/(nm·km)) LP01 ≤23 21.2
LP11 ≤23 20.5
Dispersion Slope (ps/(nm2·km)) LP01 ≤0.11 0.098
LP11 ≤0.11 0.096
Effective Area (μm2) LP01 ≥100 112
LP11 ≥140 152
Attenuation (dB/km) LP01 ≤0.21 0.19
LP11 ≤0.21 0.2
Differential Group Delay (ps/m) LP11-LP01 – 0.3 to  0.3 -0.14

 

Specifications of Two Mode Fibre (Step-Index)

Fibre Type FM SI-2
Part No. FM2010-B
Optical Characteristics@1550nm Range Typical Value
Core Diameter (μm) 14±0.5
Core Refractive Index 1.4485
Cladding Diameter (μm) 125±0.7
Cladding Non-circularity (%) < 0.7
Coating Diameter (μm) 245±10
Dispersion (ps/(nm·km)) LP01 <22 21
LP11 <21 19.5
Dispersion Slope (ps/(nm2·km)) LP01 <0.1 0.08
LP11 <0.1 0.07
Effective Area (μm2) LP01 >100 130
LP11 >200 220
Attenuation (dB/km) LP01 <0.21 0.19
LP11 <0.21 0.19
Differential Group Delay (ps/m) LP11-LP01 <2.1 1.9

 

Specifications of ULL-Two Mode Fibre (Step-Index)

Fibre Type FM SI-2-ULL
Part No. FM2010-C
Optical Characteristics@1550nm Range Typical Value
Core Diameter (μm) 16±0.2
Cladding Diameter (μm) 125±1
Cladding Non-circularity (%) < 0.7
Wavelength (nm) 1450-1700
Coating Diameter (μm) 245±10
Dispersion (ps/(nm·km)) LP01 ≤23 22.53
LP11 ≤23 22.82
Dispersion Slope (ps/(nm2·km)) LP01 ≤0.11 0.1012
LP11 ≤0.11 0.1011
Effective Area (μm2) LP01 150 – 200 169
LP11 150 – 200 167
Attenuation (dB/km) LP01 ≤0.17 0.161
LP11 ≤0.17 0.161
Differential Group Delay (ps/m) LP11-LP01 ≤5 2.36
Applications
  • Mode division multiplexing(MDM)
  • Communication
  • Sensing
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