Tongxin Wang

Disordered microstructure polymer optical fiber for stabilized coherent random fiber laser

We have demonstrated the realization of a random polymer fiber laser (RPFL) based on laser dye Pyrromethene 597-doped one-dimensional disordered polymer optical fiber (POF). The stabilized coherent laser action for the disordered POF has been obtained by the weak optical multiple scattering of the polyhedral oligomeric silsesquioxanes nanoparticles in the core of the POF in situ formed during polymerization, which was enhanced by the waveguide confinement effect. Meanwhile, the threshold of our RPFL system is almost one order of magnitude lower than that of the liquid core random fiber laser reported previously, which promotes the development of random lasers.

High Performance Temperature Sensing of Single Mode-Multimode-Single Mode Fiber With Thermo-Optic Polymer as Cladding of Multimode Fiber Segment

We present a fiber sensing for temperature with two different mode interferences. The sensor consists of a single mode-multimode-single mode (SMS) fiber with a specifically designed and synthesized thermo-optic polymer cladding, forming a leaky mode fiber interferometer and a guided one at different temperatures. A maximum temperature sensitivity of 1.4 dB/°C below 61°C and of 15 nm/°C above 72°C have been achieved. The high temperature sensitivity is mainly attributed to the high thermo-optic coefficient of the polymer cladding. The phenomenon of the fiber temperature sensing around the transformation point can be observed and studied using the proposed fiber sample. It is found that the SMS fiber sensor is more sensitive to temperature for both of the mode interferences when the refractive index (RI) of the polymer is closer to that of the multimode fiber core, and the measurement range is relatively wide.

A theoretical model of a cylindrical luminescent solar concentrator with a dye-doping coating

A novel configuration for a luminescent solar concentrator is proposed, which employs a cylindrical waveguide with a dye-doping coating and is here called a cylindrical coated luminescent solar concentrator (CC LSC). An expression for the power conversion efficiency of the configuration is first established, and then its loss mechanisms, such as escape-cone loss, self-absorption probability, and host absorption, are investigated in terms of the theoretical model. Results are also compared with those for a cylindrical doped luminescent solar concentrator (CD LSC), from which it can be concluded that the power conversion efficiency for a CC LSC is 1.17–1.48 times as much as that for a CD LSC with an equivalent absorbance and geometric gain when Rhodamine 6G is used as a luminescent species and the ratio of the coating thickness to the radius of the cylinder, d/R, is 1/100. It is also found that the power conversion efficiency for a CC LSC increases with decreasing d/R at a certain geometric gain.

High-sensitivity stress sensor based on Bragg grating in BDK-doped photosensitive polymer optical fiber

Bragg grating in a single-mode photosensitive polymer optical fiber (POF) with benzil dimethyl ketal (BDK)-doped in core has been inscribed through the Sagnac ring interference method. The Bragg wavelength of grating is about 1570nm. The stress and strain response of fiber Bragg grating (FBG) has been studied respectively. By fitting the experimental result, the strain sensitivity of FBG in POF has been found to be almost same to that of conventional silica fiber Bragg gratings. However, the stress sensitivity of FBG in POF is measured to be 421pm/MPa, which is 28 times higher than FBG in silica fiber. And such high stress sensitivity makes Bragg grating in a single-mode BDK-doped POF appear to be very attractive for constructing stress sensor with high resolution.

Optical amplification of Eu(TTA) 3 Phensolution-filled hollow optical fiber

A liquid core optical fiber (LCOF) composed of hollow fiber and a solution of Eu(TTA)(3)Phen (TTA=2-thenoyltrifluoroacetone, Phen=1, 10-phenanthroline) in dimethyl sulfoxide (DMSO) has been fabricated, in which the concentration of Eu(TTA)(3)Phen in DMSO is 0.8 wt.%, the core diameter of the LCOF is 10 μm, and the fiber length is 8.1 cm. By the end pumping with a diode-pumped solid-state laser at 355 nm, a small optical signal at 613 nm was amplified with a gain of 8.2 dB at a pump power of 203 mW. Based on this experimental result, a liquid core optical fiber amplifier can be realized by the LCOF, which has wide potential applications in many optical devices.

Long period fiber gratings in 9-vinylanthracene-containing core of photosensitive polymer optical fiber

Long period fiber gratings (LPGs) with a period of 836 & #956;m has been fabricated in POF with high photosensitive core containing 9-vinylanthracene using point-by-point method.The LPGs has 51 periods inscribed totally and the -12.8 dB loss peak at 1534 nm has been observed.