Principles and performance of tapered fiber lasers: from uniform to flared geometry

Abstract

We have studied the recently demonstrated concept of fiber lasers based on active tapered double-clad fiber (T-DCF) in copropagating and counterpropagating configurations, both theoretically and experimentally, and compared the performance to fiber lasers based on conventional cylindrical fibers in end-pumped configurations. Specific properties of T-DCFs were considered theoretically using a rate-equation model developed for tapered fibers, and a detailed comparative study was carried out experimentally. Furthermore, we have studied mode coupling effects in long adiabatic tapers due to coiling and local bending. The results allow us to conclude that, with proper fiber design, the T-DCF technology offers a high-potential alternative for bright, cost-effective fiber devices.

Ultra-large core birefringent Yb-doped tapered double clad fiber for high power amplifiers

“…The presence of borosilicate tensile rods in the cladding leads to a good mixing of the cladding modes, and therefore no shaping of the clad is required for good clad pump absorption. The double-clad pump absorption in the T-DCF is determined by a number of parameters [22]:…”

193-GHz 53-W Subpicosecond Pulse Source

“…Firstly, a tapered active fiber has a large clad diameter (up to 1.5 mm) and, consequently, can be easily pumped by low brightness laser diodes with high power. Further, a tapered fiber has better double clad absorption per unit length compared with an axially uniform fiber [24], which allows the amplifier to be made shorter. The short length and, simultaneously, a large core diameter are important aspects for mitigating non-linear effects during amplification.…”

“…This is facilitated by vignetting, a natural mechanism of amplified spontaneous emission suppression owing to tapered fiber geometry. To increase double clad absorption, the fiber was four times truncated similarly as described in [24] and [26]. The clad and core diameters of the Yb-doped tapered fiber were 770 um and 45 um at the wide end of the fiber, and 170 and 10 um at the narrow end of the fiber, respectively.…”

“…The NA of the core was 0.11. The taper had a parabolic shape with a total length of 5.5 m [24], [26]. Double clad absorption at 976 nm was 4 dB/m.…”

CO2Laser Assisted Fabrication of Micro-lensed Single-mode Optical Fiber

“…Although optical fibers have been designed primarily for optical communication, they show promise in a wide range of application areas including coupling [1], fiber lasers [2], optical sensors [3][4][5][6][7][8][9], imaging and spectroscopy [10,11], and biomedical engineering [12]. In most of the cases, micro-structuring of the optical fibers is required to produce application specific optical fibers.…”