An in-fiber Mach-Zehnder interferometer for strain measurement is proposed and experimentally demonstrated. The sensor consists of a taper followed by a short section of a multi-mode fiber （MMF） and a dispersion com...An in-fiber Mach-Zehnder interferometer for strain measurement is proposed and experimentally demonstrated. The sensor consists of a taper followed by a short section of a multi-mode fiber （MMF） and a dispersion com- pensating fiber （DCF）, which is sandwiched between two single mode fibers （SMFs）. The taper is used as a fiber coupler to excite cladding modes in the SMF, and these cladding modes transmit within the MMF and the DCF. The core mode and the cladding modes interfere in the DCF SMF fusion point to form intermodal interference. A well-defined interference spectrum is obtained in the experiment. Selected interference dips are used to measure the strain changes. The experimental results show that this device is sensitive to strain with the wavelength-referenced sensitivity of 2.6 pm/με and the power-referenced sensitivity of 0. 0027 dB/με, respectively.展开更多
The temperature-induced complex refractive index（CRI） effect of graphene is demonstrated theoretically and experimentally based on a graphene coated in-fiber MZI（Mach-Zehnder interferometer）. The relationships bet...The temperature-induced complex refractive index（CRI） effect of graphene is demonstrated theoretically and experimentally based on a graphene coated in-fiber MZI（Mach-Zehnder interferometer）. The relationships between real and imaginary parts of the graphene CRI and temperature are obtained through investigating the dip wavelength and intensity of the MZI interference spectrum changing with temperature, respectively. The temperature effect of CRI of the graphene is also analyzed theoretically. Both experimental and theoretical studies show that the real part and imaginary part of the CRI nonlinearly decrease and increase with temperature increasing, respectively. This graphene-coated in-fiber MZI structure also possesses the advantages of easy fabrication, miniaturization, low cost and robustness. It has potential applications in nanomaterial-based optic devices for communication and sensing.展开更多
An ultrasensitive magnetic field sensor based on a compact in-fiber Mach–Zehnder interferometer(MZI) created in twin-core fiber(TCF) is proposed, and its performance is experimentally demonstrated. A section of TCF w...An ultrasensitive magnetic field sensor based on a compact in-fiber Mach–Zehnder interferometer(MZI) created in twin-core fiber(TCF) is proposed, and its performance is experimentally demonstrated. A section of TCF was spliced between two sections of standard single-mode fibers, and then a microchannel was drilled through one core of the TCF by means of femtosecond laser micromachining. The TCF with one microchannel was then immersed in a water-based Fe_3O_4 magnetic fluid(MF), forming a direct component of the light propagation path,and then sealed in a capillary tube, achieving a magnetic sensing element, which merges the advantages of an MZI with an MF. Experiments were conducted to investigate the magnetic response of the proposed sensor. The developed magnetic field sensor exhibits a linear response within a measurement range from 5 to 9.5 m T and an ultrahigh sensitivity of 20.8 nm/m T, which, to our best knowledge, is 2 orders of magnitude greater than other previously reported magnetic sensors. The proposed sensor is expected to offer significant potential for detecting weak magnetic fields.展开更多
An all-optical temporal fractional order differentiator with ultrabroad bandwidth （-1.6 THz） and extremely simple fabrication is proposed and experimentally demonstrated based on an in-fiber ellipsoidal air-microcav...An all-optical temporal fractional order differentiator with ultrabroad bandwidth （-1.6 THz） and extremely simple fabrication is proposed and experimentally demonstrated based on an in-fiber ellipsoidal air-microcavity. The ellipsoidal air-microcavity is fabricated by splicing a single mode fiber （SMF） and a photonic crystal fiber （PCF） together using a simple arc-discharging technology. By changing the arc-discharging times, the propagation loss can be adjusted and then the differentiation order is tuned. A nearly Gaussian-like optical pulse with 3 dB bandwidth of 8 nm is launched into the differentiator and a 0.65 order differentiation of the input pulse is achieved with a processing error of 2.55%.展开更多
We report an efficient power tapping device working in near infra-red (800 nm) wavelength region based on UV-in- scribed 45° tilted fiber grating (45°-TFG) structure. Five 45°-TFGs were UV-inscribed in ...We report an efficient power tapping device working in near infra-red (800 nm) wavelength region based on UV-in- scribed 45° tilted fiber grating (45°-TFG) structure. Five 45°-TFGs were UV-inscribed in hydrogenated PS750 fiber using a custom-designed phase mask with different grating lengths of 3 mm, 5 mm, 9 mm, 12 mm and 15 mm, showing polarization dependent losses (PDLs) of 1 dB, 3 dB, 7 dB, 10 dB and 13 dB, respectively. The power side-tapping efficiency is clearly depending on the grating strength. It has been identified that the power tapping efficiency increases with the grating strength and deceases along the grating length. The side-tapped power profile has also been examined in azimuthal direction, showing a near-Gaussian distribution. These experimental results clearly demonstrated that 45°- TFGs may be used as in-fiber power tapping devices for applications requiring in-line signal monitoring.展开更多
针对卡尔曼反馈校正难以工程实现的问题,提出了用卡尔曼输出校正来进行组合导航滤波的方法。对卡尔曼输出校正的滤波效果进行了理论分析和仿真验证,并在基于光纤陀螺的INS/GPS(Inertial Navigation System/Global Position System)组合...针对卡尔曼反馈校正难以工程实现的问题,提出了用卡尔曼输出校正来进行组合导航滤波的方法。对卡尔曼输出校正的滤波效果进行了理论分析和仿真验证,并在基于光纤陀螺的INS/GPS(Inertial Navigation System/Global Position System)组合导航系统上进行了实验。实车实验结果表明:卡尔曼输出校正的定位精度和GPS定位精度相当,惯性导航系统误差随时间增长特性得到了有效抑制,从而验证了卡尔曼输出校正的方法在组合导航的应用中是可靠的。展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 61077006,60727004,and 61077060the China National Petroleum Corporation Science and Technology Development Projects under Grant No 2014B-4012the Science Research Plan Projects of Shaanxi Education Department under Grant No 14JK1580
文摘An in-fiber Mach-Zehnder interferometer for strain measurement is proposed and experimentally demonstrated. The sensor consists of a taper followed by a short section of a multi-mode fiber （MMF） and a dispersion com- pensating fiber （DCF）, which is sandwiched between two single mode fibers （SMFs）. The taper is used as a fiber coupler to excite cladding modes in the SMF, and these cladding modes transmit within the MMF and the DCF. The core mode and the cladding modes interfere in the DCF SMF fusion point to form intermodal interference. A well-defined interference spectrum is obtained in the experiment. Selected interference dips are used to measure the strain changes. The experimental results show that this device is sensitive to strain with the wavelength-referenced sensitivity of 2.6 pm/με and the power-referenced sensitivity of 0. 0027 dB/με, respectively.
基金Project supported by the Shandong Provincial Natural Science Foundation of China(Grant Nos.ZR2009AM017 and ZR2013FM019)the National Postdoctoral Project of China(Grant Nos.200902574 and 20080441150)+2 种基金the Shandong Provincial Education Department Foundation of China(Grant No.J06P14)the Opening Foundation of State Key Lab of Minning Disaster Prevention and Control Co-founded by Shandong Provincethe Ministry of Science and Technology of China(Grant No.MDPC201602)
文摘The temperature-induced complex refractive index（CRI） effect of graphene is demonstrated theoretically and experimentally based on a graphene coated in-fiber MZI（Mach-Zehnder interferometer）. The relationships between real and imaginary parts of the graphene CRI and temperature are obtained through investigating the dip wavelength and intensity of the MZI interference spectrum changing with temperature, respectively. The temperature effect of CRI of the graphene is also analyzed theoretically. Both experimental and theoretical studies show that the real part and imaginary part of the CRI nonlinearly decrease and increase with temperature increasing, respectively. This graphene-coated in-fiber MZI structure also possesses the advantages of easy fabrication, miniaturization, low cost and robustness. It has potential applications in nanomaterial-based optic devices for communication and sensing.
基金National Natural Science Foundation of China(NSFC)(61425007,61377090,61575128)Guangdong Science and Technology Department(2014A030308007,2014B050504010,2015B010105007,2015A030313541)+1 种基金Science and Technology Innovation Commission of Shenzhen(ZDSYS20140430164957664,GJHZ20150313093755757,KQCX20140512172532195,JCYJ20150324141711576)Pearl River Scholar Fellowships
文摘An ultrasensitive magnetic field sensor based on a compact in-fiber Mach–Zehnder interferometer(MZI) created in twin-core fiber(TCF) is proposed, and its performance is experimentally demonstrated. A section of TCF was spliced between two sections of standard single-mode fibers, and then a microchannel was drilled through one core of the TCF by means of femtosecond laser micromachining. The TCF with one microchannel was then immersed in a water-based Fe_3O_4 magnetic fluid(MF), forming a direct component of the light propagation path,and then sealed in a capillary tube, achieving a magnetic sensing element, which merges the advantages of an MZI with an MF. Experiments were conducted to investigate the magnetic response of the proposed sensor. The developed magnetic field sensor exhibits a linear response within a measurement range from 5 to 9.5 m T and an ultrahigh sensitivity of 20.8 nm/m T, which, to our best knowledge, is 2 orders of magnitude greater than other previously reported magnetic sensors. The proposed sensor is expected to offer significant potential for detecting weak magnetic fields.
基金Project supported by the the National Natural Science Foundation of China(Nos.61522509,61377002,61535012)the National HighTech Research&Development Program of China(No.SS2015AA011002)+1 种基金the Beijing Natural Science Foundation(No.4152052)supported in part by the Thousand Young Talent Program
文摘An all-optical temporal fractional order differentiator with ultrabroad bandwidth （-1.6 THz） and extremely simple fabrication is proposed and experimentally demonstrated based on an in-fiber ellipsoidal air-microcavity. The ellipsoidal air-microcavity is fabricated by splicing a single mode fiber （SMF） and a photonic crystal fiber （PCF） together using a simple arc-discharging technology. By changing the arc-discharging times, the propagation loss can be adjusted and then the differentiation order is tuned. A nearly Gaussian-like optical pulse with 3 dB bandwidth of 8 nm is launched into the differentiator and a 0.65 order differentiation of the input pulse is achieved with a processing error of 2.55%.
文摘We report an efficient power tapping device working in near infra-red (800 nm) wavelength region based on UV-in- scribed 45° tilted fiber grating (45°-TFG) structure. Five 45°-TFGs were UV-inscribed in hydrogenated PS750 fiber using a custom-designed phase mask with different grating lengths of 3 mm, 5 mm, 9 mm, 12 mm and 15 mm, showing polarization dependent losses (PDLs) of 1 dB, 3 dB, 7 dB, 10 dB and 13 dB, respectively. The power side-tapping efficiency is clearly depending on the grating strength. It has been identified that the power tapping efficiency increases with the grating strength and deceases along the grating length. The side-tapped power profile has also been examined in azimuthal direction, showing a near-Gaussian distribution. These experimental results clearly demonstrated that 45°- TFGs may be used as in-fiber power tapping devices for applications requiring in-line signal monitoring.
文摘针对卡尔曼反馈校正难以工程实现的问题,提出了用卡尔曼输出校正来进行组合导航滤波的方法。对卡尔曼输出校正的滤波效果进行了理论分析和仿真验证,并在基于光纤陀螺的INS/GPS(Inertial Navigation System/Global Position System)组合导航系统上进行了实验。实车实验结果表明:卡尔曼输出校正的定位精度和GPS定位精度相当,惯性导航系统误差随时间增长特性得到了有效抑制,从而验证了卡尔曼输出校正的方法在组合导航的应用中是可靠的。
