A new method is presented for the analysis of the modal content of a beam travelling in a waveguide. This method uses a
simple optical set up to record beam images. Depending on the application, the source can be broad band (BBS) or a
tunable laser. The method uses the eigenmode profiles of the waveguide under test, either theoretical or experimental
ones. In this case, the technique is applied to characterize the modal content of few moded large mode area (LMA)
fibers. Such LMA fibers are typically used in high power fiber lasers and amplifiers to reduce sensitivity to non-linear
effects. By calculating the scalar products of the unfolded experimental and theoretical 2D profiles, the modal content is
obtained. Access to such cost effective and easy to implement diagnosis tool will greatly help improving modal quality
preservation in components and systems based on the fundamental mode operation of few moded LMA fibers. The high
precision and performance of the method is evaluated using both computer generated and experimental data sets.
Most common high power fiber lasers use large mode area (LMA) fiber to reduce unwanted non-linearity. Such fibers
usually guide few modes but operate close to single mode regime (underfill condition) for best beam quality. For packaging
considerations or for high order mode filtering, coiling the gain fiber is mandatory. Determining the best coiling architecture
may look simple but extra care must be taken when dealing with few moded LMA fiber.
We present a formalism to quantitatively express the adiabaticity of an optical fiber coil based on the normalized coupling
coefficient betweens modes. The goal is to evaluate the capability of a coiling system to preserve the modal repartition of
the optical intensity and preserve beam quality at fiber output. We present typical coiling configurations as examples.
A simple interferometric measurement setup is proposed to study figures of merit of a coil.
Biodegradable microstructured polymer optical fibers have been created using synthetic biomaterials such as poly(L-lactic acid), poly(-caprolactone), and cellulose derivatives. Original processing techniques were utilized to fabricate a variety of biofriendly microstructured fibers that hold potential for in vivo light delivery, sensing, and controlled drug-release.