Shanghai Gengyun Industrial Co., Ltd
25/250 type double clad passive matching fiber technical definition
The 25/250 double clad fiber adopts a step index design, with a core of 25 μ m ytterbium (Yb) doped active fiber and an outer layer of 250 μ m low numerical aperture (NA ≤ 0.46) pure silicon cladding, achieving efficient absorption of pump light and lossless transmission of signal light, specially customized for kilowatt level fiber lasers/amplifiers . Five core advantages
Ultimate power carrying capacity
Supports continuous laser output of ≥ 3kW (@ 1080nm), with a cladding power density of 50MW/cm ², far exceeding the limit of single cladding fiber .
Passive matching
By accurately matching geometric parameters with NA, there is no need for fusion point mode field adapters, and the direct fusion loss with transmission fiber is less than 0.1dB.
Heat dissipation and anti damage ability
High temperature resistant coating (polyimide) can withstand temperatures greater than 300 ° C, avoiding thermal lensing effects and fiber ablation under high power.
Pump absorption efficiency
The double clad structure increases the reflection path of pump light by 5 times, with an absorption efficiency greater than 95% (single clad fiber only 30-40%)
Bending insensitivity
The critical bending radius is ≤ 7cm (@ 1550nm), suitable for compact laser equipment integration.
Revolutionary application scenarios
Value contribution in the field
Continuous cutting of 20mm thick steel plate using industrial laser cutting (power>2kW)
Aerospace welding of titanium alloy deep penetration welding (beam quality M ²<1.1)
Medical laser ablation tissue vaporization accuracy reaches 0.1mm (thermal injury zone<50 μ m)
Research ultrafast laser pulse energy>1mJ (repetition rate 100kHz)
Selection Technical Guidelines
Active fiber length: optimized according to gain requirements (typical value 5-15m)
End cap fusion: forced matching of output end cap (anti reflective damage)
Sheath selection: Metal armor (resistant to mechanical stress)>Tight buffer layer (lightweight)
Summary: 25/250 double clad fiber redefines the limits of industrial lasers with “kilowatt level power+micrometer level accuracy”, providing the underlying optical engine for high-end manufacturing. Its passive matching characteristics significantly reduce system complexity, making it the next generation core medium to replace CO ₂ lasers.