Large mode area double-clad ytterbium-doped spun tapered fiber

Abstract

We performed a comparative study of Yb-doped double-clad large mode area ( M F D = 31 µ m ) spun tapered fibers with different pitch lengths. A novel type of spun tapered fibers with constant pitch lengths of 7.5, 15, and 30 mm, internal birefringence as low as ∼ 10 − 8 , and perfect output beam quality ( M 2 &lt;<!-- 1.2 ) has been manufactured and investigated. We demonstrated the efficient direct amplification of a picosecond pulsed signal (95 ps/100 MHz, 1064 nm) in the spun active tapered fiber with optimized geometry providing an average output power of 71 W (gain 32 dB, 74% slope efficiency). Efficient green light generation ( λ = 532 n m ) with 17 W average power (1.7 µJ) and 80 pm linewidth was demonstrated using the developed master oscillator power amplifier system.

550 W picoseconds pulsed compact laser system based on a Yb-doped spun tapered double-clad fiber

“…The amplified signal is launched into the narrow part of the Yb-doped sT-DCF amplifier. The sT-DCF was fabricated using a similar technology that was previously exploited for active spun fibers [4,5]. The stepindex Yb-doped preform was assembled with a 1:12 core/clad ratio, and the numerical aperture of the active core equalled 0.1.…”

“…Recently, a new type of T-DCF with low internal birefringence (spun T-DCF) has been demonstrated with higher resistance to temperature-induced polarization degradation naturally occurring during signal amplification in PANDA-type fibers [4,5].…”

Functional Fibers and Functional Fiber-Based Components for High-Power Lasers

“…With the development of fiber preform preparation and mechanical polishing technology, the studies of tapered fibers has evolved to more degrees of freedom along the longitudinal dimension, which is driven by better pump absorption capacity and greater single-mode potential. A series of representative results at several-kilowatt-level have been reported with near single-mode outputs [76,[258][259][260][261][262][263][264][265][266][267][267][268][269][270][271][272][273][274][275][276][277][278][279][280]. Table 2 summarizes the recent progress of tapered fibers for HPFLs applications.…”

Radially polarized picosecond MOPA system based on double-clad ytterbium-doped spun tapered fiber with ring-shaped active core

“…On another side, the isotropic fiber was characterised of random variation of birefringence in the core leading to the uncontrolled distortion of the spatial distribution of polarization and destroying the radial or azimuthal polarization profile. Recently, we have demonstrated a new type of T-DCF -so-called spun T-DCF (sT-DCF) with small birefringence supporting the propagation and amplification of radially polarized light with minimum distortion [7].…”