We demonstrate an adjustable pure dispersion slope compensating-module based on strain-chirped fiber Bragg gratings. The center wavelength of the module is preserved while the pure dispersion slope is tuned.
The effects of color centers＇ absorption on fibers and interferometric fiber optical gyroscopes（IFOGs） are studied in the paper. The irradiation induced attenuation（RIA） spectra of three types of polarization-mai...The effects of color centers＇ absorption on fibers and interferometric fiber optical gyroscopes（IFOGs） are studied in the paper. The irradiation induced attenuation（RIA） spectra of three types of polarization-maintaining fibers（PMFs）, i.e.,P-doped, Ge-doped, and pure silica, irradiated at 100 Gy and 1000 Gy are measured in a wavelength range from 1100 nm to1600 nm and decomposed according to the Gaussian model. The relationship of the color centers absorption intensity with radiation dose is investigated based on a power model. Furthermore, the effects of all color centers＇ absorption on RIA and mean wavelength shifts（MWS） at 1300 nm and 1550 nm are discussed respectively. Finally, the random walk coefficient（RWC） degradation induced from RIA and the scale factor error induced by MWS of the IFOG are simulated and tested at a wavelength of 1300 nm. This research will contribute to the applications of the fibers in radiation environments.展开更多
Nonradiative recombination (NRR) centers in n-type GaN samples grown by MOCVD technique on a LT-GaN buffer layer and aAlN buffer layer have been studied by two wavelength excited photoluminescence (TWEPL). The near ba...Nonradiative recombination (NRR) centers in n-type GaN samples grown by MOCVD technique on a LT-GaN buffer layer and aAlN buffer layer have been studied by two wavelength excited photoluminescence (TWEPL). The near band-edge photoluminescence (PL) intensity decreases due to the superposition of below-gap excitation (BGE) light of energies 0.93, 1.17 and 1.27 eV over above-gap excitation (AGE) light of energy 4.66 eV. The decrease in PL intensity due to the addition of the BGE has been explained by a two levels recombination model based on SRH statistics. It indicates the presence of a pair of NRR centers in both samples, which are activated by the BGE. The degree of quenching in PL intensity for the sample grown on LT-GaN buffer layer is stronger than the sample grown on AlN buffer layer for all BGE sources. This result implies that the use of the AlN buffer layer is more effective for reducing the NRR centers in n-GaN layers than the LT-GaN buffer layer. The dependence of PL quenching on the AGE density, the BGE density and temperature has been also investigated. The NRR parameters have been quantitatively determined by solving rate equations and fitting the simulated results with the experimental data.展开更多
文摘We demonstrate an adjustable pure dispersion slope compensating-module based on strain-chirped fiber Bragg gratings. The center wavelength of the module is preserved while the pure dispersion slope is tuned.
基金supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry,China
文摘The effects of color centers＇ absorption on fibers and interferometric fiber optical gyroscopes（IFOGs） are studied in the paper. The irradiation induced attenuation（RIA） spectra of three types of polarization-maintaining fibers（PMFs）, i.e.,P-doped, Ge-doped, and pure silica, irradiated at 100 Gy and 1000 Gy are measured in a wavelength range from 1100 nm to1600 nm and decomposed according to the Gaussian model. The relationship of the color centers absorption intensity with radiation dose is investigated based on a power model. Furthermore, the effects of all color centers＇ absorption on RIA and mean wavelength shifts（MWS） at 1300 nm and 1550 nm are discussed respectively. Finally, the random walk coefficient（RWC） degradation induced from RIA and the scale factor error induced by MWS of the IFOG are simulated and tested at a wavelength of 1300 nm. This research will contribute to the applications of the fibers in radiation environments.
文摘Nonradiative recombination (NRR) centers in n-type GaN samples grown by MOCVD technique on a LT-GaN buffer layer and aAlN buffer layer have been studied by two wavelength excited photoluminescence (TWEPL). The near band-edge photoluminescence (PL) intensity decreases due to the superposition of below-gap excitation (BGE) light of energies 0.93, 1.17 and 1.27 eV over above-gap excitation (AGE) light of energy 4.66 eV. The decrease in PL intensity due to the addition of the BGE has been explained by a two levels recombination model based on SRH statistics. It indicates the presence of a pair of NRR centers in both samples, which are activated by the BGE. The degree of quenching in PL intensity for the sample grown on LT-GaN buffer layer is stronger than the sample grown on AlN buffer layer for all BGE sources. This result implies that the use of the AlN buffer layer is more effective for reducing the NRR centers in n-GaN layers than the LT-GaN buffer layer. The dependence of PL quenching on the AGE density, the BGE density and temperature has been also investigated. The NRR parameters have been quantitatively determined by solving rate equations and fitting the simulated results with the experimental data.
