GenX Precision Matched Active
LMA Double Clad Fiber
GenX fibers are the newest series of Large Mode Area (LMA) double-clad fibers, specifically tailored to enable power
scaling of multi-kW -class fiber lasers and amplifiers. Offering superior photo-darkening (PD) performances with maintained
and/or higher absorption, these fibers are optimized to benefit both CW and pulsed multi-kW systems. The 14/250 GenX
design is ideal for efficient and reliable kW-class systems. The 20/400 GenX offers the same absorption with significantly
lower PD than comparable products providing an optimized platform for high efficiency and high-reliability multi-kW CW
lasers. The 25/250 GenX product combines higher absorption and superior PD, ideal for enabling multi-kW peak power
scaling with reduced cavity length and nonlinearities.
Typical Applications
• kW Class Fiber Lasers & Amplifiers
• Materials Processing
• Military, Industrial and Medical
Features & Benefits
• Superior photo-darkening performance in both CW and pulsed applications
• Enhanced reliability for power scaling beyond kW level
• Higher absorption mitigates non-linearities and enables higher peak powers
• NuCOAT-FA-HP – for enhanced coating reliability in industrial environments
• Designed to work with existing matched passive fibers
Optical Specifications
LMA-YDF-14/250-HP-XM
1365438
LMA-YDF-20/400-HP-XM
1398875
LMA-YDF-25/250-HP-XM
Operating Wavelength
1015 – 1115 nm
1015 – 1115 nm
1015 – 1115 nm
Core NA
0.070 ± 0.005
0.065 ± 0.005
0.070 ± 0.005
First Cladding NA (5%)
≥ 0.46
≥ 0.46
≥ 0.46
Core Attenuation
≤ 20.0 dB/km @ 1200 nm
≤ 15.0 dB/km @ 1200 nm
≤ 25.0 dB/km @ 1200 nm
Cladding Attenuation
≤ 15.0 dB/km @ 1095 nm
≤ 15.0 dB/km @ 1095 nm
≤ 15.0 dB/km @ 1095 nm
Cladding Absorption
0.80 ± 0.10 dB/m at 915 nm
3.40 dB/m near 976 nm
0.40 ± 0.05 dB/m at 915 nm 2.30 ± 0.30 dB/m at 915 nm
9.90 dB/m near 976 nm
Slope Efficiency
N/A
> 70.0%@ 915 nm
N/A
Geometrical & Mechanical
Specifications
Cladding Diameter (flat-to-flat)
250.0 ± 5.0 µm
400.0 ± 10.0 µm
250.0 ± 5.0 µm
Core Diameter
14.0 ± 1.0 µm
20.0 ± 1.5 µm
25.0 ± 1.5 µm
Coating Diameter
395.0 ± 15.0 µm
550.0 ± 15.0 µm
395.0 ± 15.0 µm
Core/Clad Offset
≤ 1.00 µm
≤ 2.00 µm
≤ 1.5 µm
Coating Material
Low Index Acrylate
Low Index Acrylate
Low Index Acrylate
Prooftest Level
≥ 100 kpsi (0.7 GN/m²)
≥ 100 kpsi (0.7 GN/m²)
≥ 100 kpsi (0.7 GN/m²)
