Intracavity and resonant Raman crystal fiber laser

Abstract

We demonstrated an efficient, compact, and continuous-wave Raman crystal fiber laser (RCFL) using an intracavity and resonant χ(3) approach. The gain and nonlinear medium was Cr4+:Y3Al5O12 double-clad crystal fiber grown using the codrawing laser-heated pedestal growth technique. The RCFL threshold was only 50 mW, and the slope efficiency reached 14.3% above a pump power of 350 mW. The result is in good agreement with theory, which indicates a near-100% quantum efficiency of resonant stimulated Raman scattering.

Near-Field Lasing Dynamics of a Crystal-Glass Core–Shell Hybrid Fiber

“…With use of the CDLHPG process, − a 68-μm Cr 4+ :YAG single crystalline core was first drawn and then inserted into a fused silica capillary to form a double-shell structure with a core diameter of 20 μm. The inner and outer shell diameters were 93 and 320 μm, respectively.…”

“…The high-emission cross-section, low-threshold lasing, and efficient χ (3) process of crystalline-core fibers signify numerous promising applications in telecommunications and metrology as well as emerging areas such as integrated photonics and biomedical applications. − A double-shell architecture grown by a co-drawing laser-heated pedestal growth (CDLHPG) technique is a simple yet effective approach that allows strong wave confinement and a small mode diameter, which, due to the large refractive index difference (Δ n ∼ 1.1) between the crystal core (Y 3 Al 5 O 12 ; YAG) and the glass inner shell (YAG + SiO 2 ), − ,− allows higher pump intensities, lower lasing thresholds, and enhanced nonlinearity. However, many applications require single-mode output, and multimode operation of crystalline-core fibers is considered problematic due to the large Δ n .…”

Defect-driven fiber-based UV-VIS broadband white light generation

“…With three diameter reduction steps by the LHPG technique [2], [3], a 40-μm Ti:sapphire single crystalline core was grown in an ambient (i.e., oxidizing) atmosphere. At this stage, the nominal concentration of Ti in the sample was decreased to be ~50 ppm, because of the Ti ions evaporate out during the LHPG process.…”

Toward Single-Mode Active Crystal Fibers for Next-Generation High-Power Fiber Devices

“…In the field of high-power active single-mode fiber devices, the exploration of materials with unique properties as relevant alternatives to existing glass-based fibers is critical to achieving further improvement in the power that such devices can carry. Crystal fiber, a typical example of the crystalline-core configuration, features exceptional optical properties in comparison to conventional glass or polymer fiber, − such as a high emission cross-section and low-threshold lasing, − high thermal loading and a high laser damage threshold, − and efficient χ (3) processes; − crystal fiber is expected to provide a key architecture for scaling the fiber laser power in the near future. Scaling fiber lasers and amplifiers to high average powers requires materials with high thermal conductivity such that heat can be easily dissipated from the interior, in this case, from the crystalline core of the fiber.…”