Broadband and high-brightness light source: glass-clad Ti:sapphire crystal fiber

Abstract

High-brightness near-infrared broadband amplified spontaneous emission (ASE) was generated by glass-clad Ti:sapphire crystal fibers, which were developed using the co-drawing laser-heated pedestal growth method. As much as 29.2 mW of ASE power was generated using 520 nm laser diodes as the excitation source on an a-cut, 18 μm core-diameter Ti:sapphire crystal fiber (CF). The 3 dB bandwidth was 163.8 nm, and the radiance was 53.94 W·mm(-2) sr(-1). The propagation loss of the glass-clad sapphire CF measured using the cutback method was 0.017 cm(-1) at 780 nm. For single-mode applications, more than 100 μW of power was coupled into a SM600 single-mode fiber.

Application of Sapphire-Fiber-Bragg-Grating-Based Multi-Point Temperature Sensor in Boilers at a Commercial Power Plant

“…For an air-clad sapphire FBG, the reflection peaks of different modes can be easily distinguished once the diameter is smaller than 20 μm and each peak has a <1 nm bandwidth [25]. The fabrication of a small diameter sapphire fiber can be achieved by laser-heated pedestal growth (LHPG) fabrication [28], in which diameters down to about 20 microns can be achieved, or by chemical-etching processing [29], in which diameters down to one micron or below can be achieved.…”

Instant precipitation of KMgF3:Ni2+ nanocrystals with broad emission (1.3‐2.2 μm) for potential combustion gas sensors

“…For example, C 2 H 4 can be detected at around 1.0 μm, NH 3 at 1.5 μm, or CO around 5 μm . While the MIR spectral range remains difficult to access with native laser sources, there are mature devices on account of rare earth (RE) functionalized fiber lasers for the lower NIR regime . Also for the transitional range of 1.5‐2 μm, there is still a lack of emission sources with sufficiently high bandwidth.…”

“…The d‐d transitions of transition metals (TMs), on the other hand, are super sensitive to the surrounding environment of the active ion, depending on TM species enabling broad and tunable NIR emission across the absorption bands of the above‐mentioned types of gases . Yet, various challenges remain for the traditional techniques, including material fabrication (often involving single‐crystal growth) and the ability to produce optical fiber . Here, TM‐doped glasses appear to be highly attractive due to commonly available fiber drawing technology.…”

“…[4][5][6] While the MIR spectral range remains difficult to access with native laser sources, there are mature devices on account of rare earth (RE) functionalized fiber lasers for the lower NIR regime. [19][20][21][22] Also for the transitional range of 1.5-2 lm, there is still a lack of emission sources with sufficiently high bandwidth. For example, this addresses gases such as C 2 H 6 (~1.6 lm), CH 4 (1.65 lm), H 2 CO (1.7 lm), and NO (1.9 lm), relevant in air pollution control, mining, and industrial emissions.…”

“…[29][30][31] Yet, various challenges remain for the traditional techniques, including material fabrication (often involving single-crystal growth) and the ability to produce optical fiber. 20,29,32 Here, TMdoped glasses appear to be highly attractive due to commonly available fiber drawing technology. However, such glasses normally exhibit no or negligible NIR activity due to the large non-radiative transition probability resulting from their inherently disordered structure.…”