Pub Date : 2012-12-01DOI: 10.1109/PGC.2012.6458007
F. Vollmer
Whispering gallery mode (WGM) biosensors derive their unprecedented sensitivity for label-free detection of biomolecules from the high-quality (Q) factor of an optical resonance phenomenon. Plasmonic excitations in metal nanostructures which are able to localize the WGM field at the target binding site can further enhance sensitivity by local electric field amplification. Random nanoparticle layers and nanopost antennas are investigated for this purpose, and an efficiency parameter is introduced to quantitate the local field overlap with analyte molecules, a pre-requisite for single molecule detection.
{"title":"Plasmon-enhanced whispering gallery mode biosensing","authors":"F. Vollmer","doi":"10.1109/PGC.2012.6458007","DOIUrl":"https://doi.org/10.1109/PGC.2012.6458007","url":null,"abstract":"Whispering gallery mode (WGM) biosensors derive their unprecedented sensitivity for label-free detection of biomolecules from the high-quality (Q) factor of an optical resonance phenomenon. Plasmonic excitations in metal nanostructures which are able to localize the WGM field at the target binding site can further enhance sensitivity by local electric field amplification. Random nanoparticle layers and nanopost antennas are investigated for this purpose, and an efficiency parameter is introduced to quantitate the local field overlap with analyte molecules, a pre-requisite for single molecule detection.","PeriodicalId":158783,"journal":{"name":"2012 Photonics Global Conference (PGC)","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125343771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/PGC.2012.6457995
Q. Meng, Xinyong Dong, Zhemin Chen, K. Ni
A fiber sensor scheme for simultaneous measurement of curvature and temperature is presented. The sensor head is formed by combining a fiber Bragg grating (FBG) with a all-fiber Mach-Zehnder interferometer (MZI), which is formed by cascading two waist-enlarged fiber tapers. The MZI is sensitive to curvature and surrounding temperature, while the FBG is only sensitive to the later. As a result, simultaneous measurement of curvature and temperature can be achieved by monitoring wavelength shifts of the MZI and the FBG. Sensitivities of 6.75 nm/m-1 and 54.7 pm/°C are achieved experimentally for curvature and temperature measurements, respectively. This sensor has a compact configuration, because the FBG is inset into the MZI. Furthermore, the sensor also has the advantages of low-cost fabrication process and good physical strength.
{"title":"Simultaneous measurement of curvature and temperature based on two waist-enlarged fiber tapers and a fiber Bragg grating","authors":"Q. Meng, Xinyong Dong, Zhemin Chen, K. Ni","doi":"10.1109/PGC.2012.6457995","DOIUrl":"https://doi.org/10.1109/PGC.2012.6457995","url":null,"abstract":"A fiber sensor scheme for simultaneous measurement of curvature and temperature is presented. The sensor head is formed by combining a fiber Bragg grating (FBG) with a all-fiber Mach-Zehnder interferometer (MZI), which is formed by cascading two waist-enlarged fiber tapers. The MZI is sensitive to curvature and surrounding temperature, while the FBG is only sensitive to the later. As a result, simultaneous measurement of curvature and temperature can be achieved by monitoring wavelength shifts of the MZI and the FBG. Sensitivities of 6.75 nm/m-1 and 54.7 pm/°C are achieved experimentally for curvature and temperature measurements, respectively. This sensor has a compact configuration, because the FBG is inset into the MZI. Furthermore, the sensor also has the advantages of low-cost fabrication process and good physical strength.","PeriodicalId":158783,"journal":{"name":"2012 Photonics Global Conference (PGC)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125791037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/PGC.2012.6457932
Ching-Yun Huang, Wei-Huan Fu, V. Hsiao
We demonstrate an optically switchable all-fiber optical polarizer based on a side-polished fiber (SPF) overlaid with a photoresponsive liquid crystal (PLC) containing a nematic LC and a photosensitive azobenzene molecule. The trans-cis photoisomerization of azobenzene modulates the overlaid LC's birefringence, changes the refractive index (RI) of the PLC-overlaid SPF, and further controls the polarization of light propagating within the fiber.
{"title":"Optically switchable all-fiber optic polarizer","authors":"Ching-Yun Huang, Wei-Huan Fu, V. Hsiao","doi":"10.1109/PGC.2012.6457932","DOIUrl":"https://doi.org/10.1109/PGC.2012.6457932","url":null,"abstract":"We demonstrate an optically switchable all-fiber optical polarizer based on a side-polished fiber (SPF) overlaid with a photoresponsive liquid crystal (PLC) containing a nematic LC and a photosensitive azobenzene molecule. The trans-cis photoisomerization of azobenzene modulates the overlaid LC's birefringence, changes the refractive index (RI) of the PLC-overlaid SPF, and further controls the polarization of light propagating within the fiber.","PeriodicalId":158783,"journal":{"name":"2012 Photonics Global Conference (PGC)","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116041545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/PGC.2012.6457939
P. Pukhrambam, Ming-Hsueh Chuang, San-Liang Lee, G. Keiser, Y. Hung, J. W. Simatupang
We investigated experimentally the effects of optical injection locking on the performance of a directly modulated semiconductor distributed feedback laser, aiming for radio-over-fiber (RoF) applications. The resonance frequency and noise level are measured at various frequency detuning and external injection ratios. Under optical injection locking with a -2.9dB injection ratio and -12.5GHz detuning, the resonance frequency improved 2.81 times and noise level at the peak reduced by 3.5dB compared to a free running laser. We also achieved 5dB dynamic range enhancement with the same injection conditions. A resonance frequency improvement of 4.2 times was achieved with increased detuning. Performances of a ROF system were evaluated at RF frequencies of 2, 2.5 and 3GHz using a 64-QAM signal. From the error vector magnitude measurements, the optical injection locking can both enhance the linearity and reduce the noise for direct modulation, and thus extending the dynamic range of input RF signals.
{"title":"Performance enhancement of radio-over-fiber system by optical injection locking of a directly modulated semiconductor laser","authors":"P. Pukhrambam, Ming-Hsueh Chuang, San-Liang Lee, G. Keiser, Y. Hung, J. W. Simatupang","doi":"10.1109/PGC.2012.6457939","DOIUrl":"https://doi.org/10.1109/PGC.2012.6457939","url":null,"abstract":"We investigated experimentally the effects of optical injection locking on the performance of a directly modulated semiconductor distributed feedback laser, aiming for radio-over-fiber (RoF) applications. The resonance frequency and noise level are measured at various frequency detuning and external injection ratios. Under optical injection locking with a -2.9dB injection ratio and -12.5GHz detuning, the resonance frequency improved 2.81 times and noise level at the peak reduced by 3.5dB compared to a free running laser. We also achieved 5dB dynamic range enhancement with the same injection conditions. A resonance frequency improvement of 4.2 times was achieved with increased detuning. Performances of a ROF system were evaluated at RF frequencies of 2, 2.5 and 3GHz using a 64-QAM signal. From the error vector magnitude measurements, the optical injection locking can both enhance the linearity and reduce the noise for direct modulation, and thus extending the dynamic range of input RF signals.","PeriodicalId":158783,"journal":{"name":"2012 Photonics Global Conference (PGC)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127896773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/PGC.2012.6458055
Xuantao Su, Yan Yang, Xuming Sun, Xu Qiao, K. Song, B. Kong
Flow cytometry has wide applications in cell biology and medicine. Compared with conventional fluorescence labeling, light scattering can be adopted as a label-free cytometric method. Integration of optics with microfluidics, the optofluidic technology may help for the advancement of the next generation miniaturized label-free cytometry. Optofluidic label-free cytometry that can obtain two dimensional light scattering patterns from single cells has been developed. Laser light is fibered-coupled onto a microfluidic chip, and light scattering patterns can be obtained via a CMOS detector. Light scattering from cells or particles in such a cytometric setup can be simulated via the Mie theory or finite-difference time-domain (FDTD) method. The experimental results agree well with the simulated ones for yeast cells. Further development of the optofluidic label-free cytometric technique may help for early cancer screening, and provide portable instruments for clinics and home care.
{"title":"Miniaturized optofluidic label-free cytometry","authors":"Xuantao Su, Yan Yang, Xuming Sun, Xu Qiao, K. Song, B. Kong","doi":"10.1109/PGC.2012.6458055","DOIUrl":"https://doi.org/10.1109/PGC.2012.6458055","url":null,"abstract":"Flow cytometry has wide applications in cell biology and medicine. Compared with conventional fluorescence labeling, light scattering can be adopted as a label-free cytometric method. Integration of optics with microfluidics, the optofluidic technology may help for the advancement of the next generation miniaturized label-free cytometry. Optofluidic label-free cytometry that can obtain two dimensional light scattering patterns from single cells has been developed. Laser light is fibered-coupled onto a microfluidic chip, and light scattering patterns can be obtained via a CMOS detector. Light scattering from cells or particles in such a cytometric setup can be simulated via the Mie theory or finite-difference time-domain (FDTD) method. The experimental results agree well with the simulated ones for yeast cells. Further development of the optofluidic label-free cytometric technique may help for early cancer screening, and provide portable instruments for clinics and home care.","PeriodicalId":158783,"journal":{"name":"2012 Photonics Global Conference (PGC)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116911121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/PGC.2012.6457992
Zhe Xiao, F. Luan, T. Liow, Jing Zhang, P. Shum
An optimized grating coupler featuring both ultra-broad bandwidth and high-efficiency has been achieved for the first time for the +1 diffraction order at a central operating wavelength 1.55 μm for TM polarization in horizontal slot waveguides. With proper design of the thickness of the groove thickness in grating region, we achieved a 60 nm 1 dB bandwidth, and the 3 dB bandwidth is 92 nm covering the entire C-band, and most of L-band and S-band. It is nearly two times more than the previously reported value. Maximum coupling efficiency of 65% has been achieved for positive detuned grating couplers with incident light from SMF at 8o. Sensitivity to fabrication and alignment tolerances of the structure has been analyzed.
{"title":"Tolerant wideband high-efficiency grating coupler for TM mode excitation","authors":"Zhe Xiao, F. Luan, T. Liow, Jing Zhang, P. Shum","doi":"10.1109/PGC.2012.6457992","DOIUrl":"https://doi.org/10.1109/PGC.2012.6457992","url":null,"abstract":"An optimized grating coupler featuring both ultra-broad bandwidth and high-efficiency has been achieved for the first time for the +1 diffraction order at a central operating wavelength 1.55 μm for TM polarization in horizontal slot waveguides. With proper design of the thickness of the groove thickness in grating region, we achieved a 60 nm 1 dB bandwidth, and the 3 dB bandwidth is 92 nm covering the entire C-band, and most of L-band and S-band. It is nearly two times more than the previously reported value. Maximum coupling efficiency of 65% has been achieved for positive detuned grating couplers with incident light from SMF at 8o. Sensitivity to fabrication and alignment tolerances of the structure has been analyzed.","PeriodicalId":158783,"journal":{"name":"2012 Photonics Global Conference (PGC)","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117245831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/PGC.2012.6457975
B. Meng, Qijie Wang
We report the design and demonstration of ~14 μm quantum cascade lasers based on the three-phonon-resonance active region design. The as-cleaved device with 40 periods of active region and size of 3.8 mm×28μm shows ~10 mW peak power at 280 K and maximum working temperature of 295 K. Due to the Stark effect, the laser wavelength blue-shifts from 13.75 to 13.4 μm for temperature changing from 200 K to 295 K at around roll-over current density, with characteristics temperature of 440 K.
{"title":"Quantum cascade lasers of λ ≈ 14µm based on three-phonon-resonance design","authors":"B. Meng, Qijie Wang","doi":"10.1109/PGC.2012.6457975","DOIUrl":"https://doi.org/10.1109/PGC.2012.6457975","url":null,"abstract":"We report the design and demonstration of ~14 μm quantum cascade lasers based on the three-phonon-resonance active region design. The as-cleaved device with 40 periods of active region and size of 3.8 mm×28μm shows ~10 mW peak power at 280 K and maximum working temperature of 295 K. Due to the Stark effect, the laser wavelength blue-shifts from 13.75 to 13.4 μm for temperature changing from 200 K to 295 K at around roll-over current density, with characteristics temperature of 440 K.","PeriodicalId":158783,"journal":{"name":"2012 Photonics Global Conference (PGC)","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132493820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/PGC.2012.6458113
S. Harun, H. Ahmad, A. A. Jasim, A. Sulaiman
Fabrication of various microfiber structures such as loop, knot, mach-zenhder interferometer and coil resonators have been successfully demonstrated using a flame brushing technique. A compact inline microfiber Mach-Zehnder interferometer (MMZI) is also demonstrated for high temperature sensing. The temperature sensitivity of the device was measured to be 13.4 pm/°C with an excellent linearity for temperature measurement up to 800°C. Another MMZI structure is also proposed for application in tunable Erbium-doped fiber laser (EDFL). The operating wavelength of the laser can be tuned from 1530.2 nm to 1532.7 nm by changing the path length difference inside the MMZI from 1.6 mm to 2.7 mm at room temperature.
{"title":"Microfiber structures and its sensor and laser applications","authors":"S. Harun, H. Ahmad, A. A. Jasim, A. Sulaiman","doi":"10.1109/PGC.2012.6458113","DOIUrl":"https://doi.org/10.1109/PGC.2012.6458113","url":null,"abstract":"Fabrication of various microfiber structures such as loop, knot, mach-zenhder interferometer and coil resonators have been successfully demonstrated using a flame brushing technique. A compact inline microfiber Mach-Zehnder interferometer (MMZI) is also demonstrated for high temperature sensing. The temperature sensitivity of the device was measured to be 13.4 pm/°C with an excellent linearity for temperature measurement up to 800°C. Another MMZI structure is also proposed for application in tunable Erbium-doped fiber laser (EDFL). The operating wavelength of the laser can be tuned from 1530.2 nm to 1532.7 nm by changing the path length difference inside the MMZI from 1.6 mm to 2.7 mm at room temperature.","PeriodicalId":158783,"journal":{"name":"2012 Photonics Global Conference (PGC)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128095627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/PGC.2012.6458077
Zi-jian Wu, Yang Ming, Fei Xu, Yan-qing Lu
We propose optical frequency comb generation in a monolithic micro-ring resonator. Being different from the previously reported nonlinear optical frequency combs, our scheme is based on more efficient quadratic frequency conversion rather than the third-order nonlinearity. To overcome the phase mismatch, a partly poled nonlinear ring is employed. Cascading second harmonic generation and parametric down conversion processes thus are realized through quasi-phase matching (QPM). Coupling equations are used to describe the related nonlinear interactions among different whispering-gallery modes, showing some interesting characteristics that are different from conventional QPM technology.
{"title":"Optical frequency comb generation by cascaded second-order nonlinear effect in a quasi-phase matched micro-ring resonator","authors":"Zi-jian Wu, Yang Ming, Fei Xu, Yan-qing Lu","doi":"10.1109/PGC.2012.6458077","DOIUrl":"https://doi.org/10.1109/PGC.2012.6458077","url":null,"abstract":"We propose optical frequency comb generation in a monolithic micro-ring resonator. Being different from the previously reported nonlinear optical frequency combs, our scheme is based on more efficient quadratic frequency conversion rather than the third-order nonlinearity. To overcome the phase mismatch, a partly poled nonlinear ring is employed. Cascading second harmonic generation and parametric down conversion processes thus are realized through quasi-phase matching (QPM). Coupling equations are used to describe the related nonlinear interactions among different whispering-gallery modes, showing some interesting characteristics that are different from conventional QPM technology.","PeriodicalId":158783,"journal":{"name":"2012 Photonics Global Conference (PGC)","volume":"22 7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134382859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/PGC.2012.6458116
Xiaowei Zhou, Lingyi Chen, C. Tse, Trevor B. Penney, Nanguang Chen
The optical path of near-infrared light propagation in multi-layer brain models was investigated by theoretical and computational analysis for three DOT systems. The brain models are comprised a three-layer slab or three-layer semi-sphere intersected by a same size three-layer slab. In each model, the light penetration depths and the shapes of light paths for different source and detector pairs were analyzed with a numerical diffusion forward model based on the finite element method. The simulation results revealed that the light path was affected by source and detector distance, and varied in the different brain models. Specifically, the effective penetration depths were different for the different DOT systems and deeper penetration depth was observed using a fast time-domain DOT system.
{"title":"Theoretical investigation of near-infrared light path in multi-layer brain models for three DOT systems","authors":"Xiaowei Zhou, Lingyi Chen, C. Tse, Trevor B. Penney, Nanguang Chen","doi":"10.1109/PGC.2012.6458116","DOIUrl":"https://doi.org/10.1109/PGC.2012.6458116","url":null,"abstract":"The optical path of near-infrared light propagation in multi-layer brain models was investigated by theoretical and computational analysis for three DOT systems. The brain models are comprised a three-layer slab or three-layer semi-sphere intersected by a same size three-layer slab. In each model, the light penetration depths and the shapes of light paths for different source and detector pairs were analyzed with a numerical diffusion forward model based on the finite element method. The simulation results revealed that the light path was affected by source and detector distance, and varied in the different brain models. Specifically, the effective penetration depths were different for the different DOT systems and deeper penetration depth was observed using a fast time-domain DOT system.","PeriodicalId":158783,"journal":{"name":"2012 Photonics Global Conference (PGC)","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122388584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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