ACTIVE LMA AIR-CLAD FIBERS

Double clad fibers is a group of very efficient brightness converting fibers. Such fibers are pumped by multimode diodes and provides lasing/amplification in a single mode.
Traditionally, double clad fibers have been made as step-index fibers of different materials - most typically with a polymer outer cladding. With the PCF technology, the fibers can be made of all silica.
Double clad fibers made with photonic crystal fiber technology are known as air-clad fibers and provide a range of new benefits: The extremely high numerical aperture (NA) for the pump core/inner cladding is possible, allowing efficient pumping with inexpensive/high power broad area emitting pumps. The large mode area for the single mode signal facilitating high power levels while avoiding nonlinearities and providing a good overlap between the pump guide and the signal guide area (= high pump absorption, high efficiency). The fibers have efficient mode and ray scrambling even for circular pump cores and the all glass design has a much higher damage threshold than standard double-clad fibers.

A variety of core dopants are possible such as Yb, Nd, Er, Er/Yb, Tm, Ho and others. Co-doping with photosensitive materials is also possible to allow fiber grating inscription. The fiber parameter space is very wide and a large range of signal and pump core dimensions are possible. Please contact our sales department for further information.

Advantages

- High NA (0.6-0.7)
- High pump absorption (up to 30 dB/m)
- Short fiber lengths
- All-glass design - no polymers - for excellent power handling
- Good thermal properties
- High reliability
- No skew-rays or whispering gallery modes.