12-250 Active and Passive LMA Double Clad Optical Fibers for Fiber Laser Applications

The OFS family of TrueLase 12-250 LMA Double Clad Optical Fibers is an ideal tool for integrated high power fiber lasers and amplifiers. Our fibers combine high clad absorption, precision matched fiber waveguide designs and unprecedented manufacturing control ensuring easy integration across the entire laser architecture.
Unit of Measure


Core Numerical Aperture

N/A 0.070 ± 0.005

Mode Field Diameter

N/A LP01 @ 1070nm 12 ± 0.8 µm

Optical Specifications

Background Loss at 1150 nm

N/A <10 dB/km

Cladding Loss at 1100 nm

N/A <10 dB/km

LP01 Mode Field Diameter (MFD) at 1070 nm

N/A 12 ± 0.8 µm

Cladding Absorption at 915 nm

N/A 0.65 ± 0.15 dB/m

How To Order:

Order By Item #

N/A 79539

Mechanical and Testing Data

Proof Test Level

N/A 100 kpsi

Physical and Material Parameters

Core Concentricity Error

N/A <0.3 µm

Cladding Diameter (Flat to Flat)

N/A 250 ± 3 µm

Coating Outside Diameter

N/A 400 ± 15 µm

Coating Type

N/A TrueClad™ Low Index Coating

Fiber Geometry

N/A Octagonal


Fiber Efficiency (With Respect to 2 W Launched Power)1 N/A >71 %



N/A High Power Fiber Lasers and Amplifiers Industrial, Medical and Military Lasers for Material Processing


Industry Standard

N/A RoHS ISO 9001

Additional Information

Additional Information

N/A Development of the new OFS TrueLase™ Optical Fiber family was driven by an increasing demand for a reliable fiber supply in the rapidly growing fiber laser market space. Fiber lasers had their start in the erbium doped amplification work done in the early 1990’s. OFS, a global market leader in the design and manufacture of erbium doped fibers, possesses the expertise and experience in fiber fabrication technology necessary to meet that demand. OFS has been developing and manufacturing high power components and modules for many years and understands the reliability standards expected in the diverse material processing applications.

Features and Benefits

Features and Benefits

  • Enables easy & efficient integration for monolithic fiber lasers and amplifiers
  • Excellent fiber consistency and uniformity using OFS proprietary RE vapor phase delivery process
  • TrueClad™ low index coating for extensive durability in sensitive environment and operating conditions


N/A Specifications are preliminary and are subject to change.

TrueClad™ and TrueLase™ are trademarks of OFS Fitel, LLC. OFS reserves the right to make changes to the prices.

  • 1 915 nm forward pumped amplifier.