We investigate slow light effect of subwavelength gratings via Rayleigh Anomaly on both infinite and finite size high index contrast gratings. Our results show that the local group velocity of the transmitted light can be significantly reduced due to the optical vortex, which can inspire a new mechanism to enhance light-matter interactions for optical sensing and photo detection. However, the slow light effect will diminish as the transmitted light propagates further away from the grating surface, and the slow-down factor decreases as the grating size shrinks.
{"title":"Slow-light effect via Rayleigh anomaly in high contrast gratings","authors":"Kyoung-Youm Kim, Xinyuan Chong, Alan X. Wang","doi":"10.1117/12.2214041","DOIUrl":"https://doi.org/10.1117/12.2214041","url":null,"abstract":"We investigate slow light effect of subwavelength gratings via Rayleigh Anomaly on both infinite and finite size high index contrast gratings. Our results show that the local group velocity of the transmitted light can be significantly reduced due to the optical vortex, which can inspire a new mechanism to enhance light-matter interactions for optical sensing and photo detection. However, the slow light effect will diminish as the transmitted light propagates further away from the grating surface, and the slow-down factor decreases as the grating size shrinks.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124902547","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}
This paper reports on the progress related to a multichannel photonic alignment concept, which aims to achieve submicrometer alignment of the waveguides of two photonic integrated circuits (PICs). The concept consists of two steps: chip-to-chip positioning and fixing provide a coarse alignment after which waveguide-to-waveguide positioning and fixing result in a fine alignment. For the waveguide-to-waveguide alignment, mechanically flexible waveguides are used. Positioning of the waveguides is performed by integrated MEMS actuators. The flexible waveguides and the actuators are both integrated in one of the PICs. This paper reports on the fabrication and the mechanical characterization of the suspended waveguide structures. The flexible waveguide array is created in a PIC which is based on TriPleX technology, i.e. a silicon nitride (Si3N4) core encapsulated in a silicon dioxide (SiO2) cladding. The realized flexible waveguide structures consist of parallel cantilevered waveguide beams and a crossbar that connects the free ends of the waveguide beams. The fabrication of suspended structures consisting of a thick, i.e. 15 µm, TriPleX layer stack is challenged by the compressive mean stress in the SiO2. We have developed a fabrication method for the reliable release of flexible TriPleX structures, resulting in a 96% yield of cantilever beams. The realized suspended waveguide arrays have a natural out-of-plane deformation, which is studied using white light interferometry. Suspended waveguide beams reveal a downward slope at the base of the beams close to 0:5_. In addition to this slope, the beams have a concave upward profile. The constant curvature over the length of the waveguide beams is measured to range from 0:2 µm to 0:8 µm. The profiles measured over the length of the crossbars do not seem to follow a circular curvature. The variation in deflection within crossbars is measured to be smaller than 0:2 µm.
{"title":"Mechanically flexible waveguide arrays for optical chip-to-chip coupling","authors":"T. Peters, M. Tichem","doi":"10.1117/12.2205227","DOIUrl":"https://doi.org/10.1117/12.2205227","url":null,"abstract":"This paper reports on the progress related to a multichannel photonic alignment concept, which aims to achieve submicrometer alignment of the waveguides of two photonic integrated circuits (PICs). The concept consists of two steps: chip-to-chip positioning and fixing provide a coarse alignment after which waveguide-to-waveguide positioning and fixing result in a fine alignment. For the waveguide-to-waveguide alignment, mechanically flexible waveguides are used. Positioning of the waveguides is performed by integrated MEMS actuators. The flexible waveguides and the actuators are both integrated in one of the PICs. This paper reports on the fabrication and the mechanical characterization of the suspended waveguide structures. The flexible waveguide array is created in a PIC which is based on TriPleX technology, i.e. a silicon nitride (Si3N4) core encapsulated in a silicon dioxide (SiO2) cladding. The realized flexible waveguide structures consist of parallel cantilevered waveguide beams and a crossbar that connects the free ends of the waveguide beams. The fabrication of suspended structures consisting of a thick, i.e. 15 µm, TriPleX layer stack is challenged by the compressive mean stress in the SiO2. We have developed a fabrication method for the reliable release of flexible TriPleX structures, resulting in a 96% yield of cantilever beams. The realized suspended waveguide arrays have a natural out-of-plane deformation, which is studied using white light interferometry. Suspended waveguide beams reveal a downward slope at the base of the beams close to 0:5_. In addition to this slope, the beams have a concave upward profile. The constant curvature over the length of the waveguide beams is measured to range from 0:2 µm to 0:8 µm. The profiles measured over the length of the crossbars do not seem to follow a circular curvature. The variation in deflection within crossbars is measured to be smaller than 0:2 µm.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122548745","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}
H. Price, T. Ozawa, N. Goldman, O. Zilberberg, I. Carusotto
Recent advances in silicon ring-resonator arrays have stimulated the development of topological lattices for photons, with potential applications in integrated photonic devices. Taking inspiration from ultracold atoms, we propose how such arrays can be extended into an additional synthetic dimension by coupling together the different modes of each ring resonator.1 In this way, a 1D resonator chain can become an effective 2D system, while a 3D resonator array can be exploited as a 4D photonic lattice. As an example of the power of this approach, we discuss how to experimentally realise an optical analogue of the 4D quantum Hall effect for the first time. This opens up the way towards the exploration of higher-dimensional lattices in integrated photonics.
{"title":"Towards four-dimensional photonics","authors":"H. Price, T. Ozawa, N. Goldman, O. Zilberberg, I. Carusotto","doi":"10.1117/12.2218539","DOIUrl":"https://doi.org/10.1117/12.2218539","url":null,"abstract":"Recent advances in silicon ring-resonator arrays have stimulated the development of topological lattices for photons, with potential applications in integrated photonic devices. Taking inspiration from ultracold atoms, we propose how such arrays can be extended into an additional synthetic dimension by coupling together the different modes of each ring resonator.1 In this way, a 1D resonator chain can become an effective 2D system, while a 3D resonator array can be exploited as a 4D photonic lattice. As an example of the power of this approach, we discuss how to experimentally realise an optical analogue of the 4D quantum Hall effect for the first time. This opens up the way towards the exploration of higher-dimensional lattices in integrated photonics.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127689972","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}
R. Walker, H. Ding, D. Coulas, D. Grobnic, P. Lu, S. Mihailov, M. Duchesne, R. Hughes, D. McCalden, Ryan Burchat, Robert Yandon
Femtosecond pulse duration infrared laser (fs-IR) written fiber Bragg gratings (FBGs), have demonstrated great potential for extreme environment sensing. Harsh environments are inherent to the advanced power plant technologies under development to reduce greenhouse gas emissions. The performance of new power systems are currently limited by the lack of sensors and controls capable of withstanding the high temperature, pressure and corrosive conditions present. This paper discusses fabrication and deployment of several fs-IR written FBG arrays, for monitoring the temperature distribution within a fluidized bed combustor. Results include: calibration data to ~ 1100 °C, discussion of deployment strategies, contrast with thermocouple data, and comments on reliability.
{"title":"High temperature monitoring of an oxy-fuel fluidized bed combustor using femtosecond infrared laser written fiber Bragg gratings","authors":"R. Walker, H. Ding, D. Coulas, D. Grobnic, P. Lu, S. Mihailov, M. Duchesne, R. Hughes, D. McCalden, Ryan Burchat, Robert Yandon","doi":"10.1117/12.2209399","DOIUrl":"https://doi.org/10.1117/12.2209399","url":null,"abstract":"Femtosecond pulse duration infrared laser (fs-IR) written fiber Bragg gratings (FBGs), have demonstrated great potential for extreme environment sensing. Harsh environments are inherent to the advanced power plant technologies under development to reduce greenhouse gas emissions. The performance of new power systems are currently limited by the lack of sensors and controls capable of withstanding the high temperature, pressure and corrosive conditions present. This paper discusses fabrication and deployment of several fs-IR written FBG arrays, for monitoring the temperature distribution within a fluidized bed combustor. Results include: calibration data to ~ 1100 °C, discussion of deployment strategies, contrast with thermocouple data, and comments on reliability.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134379897","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}
D. Panda, S. Shetty, A. Balgarkashi, H. Ghadi, N. Sehara, S. Chakrabarti
In this paper, we have reported the optical and electrical properties of strain coupled multi-stack quantum dot infrared photodetectors (QDIPs) of In0.5Ga0.5As dots with different capping compositions. Bilayer, trilayer, pentalayer and heptalayer coupled QDIPs are grown by solid source molecular beam epitaxy with one set of samples containing conventional GaAs capping (12nm) and second set containing a combinational capping of In0.15Ga0.85As (3nm) and GaAs (9nm) layers with same total thickness. The entire set of strain coupled quantum dots (QDs) shows a red shift in ground state photoluminescence peak in comparison to the uncoupled structures. Due to the reduction in indium interdiffusion from In0.5Ga0.5As dots in the combinational capped structures, a higher redshift is observed compared to the GaAs capped structures, which attributes larger dot size in the former ones. Full width half maximum value (FWHM) of In0.15Ga0.85As/GaAs capped QDs are lower, showing uniform distribution of dot size compared to the corresponding GaAs capped QDs. Trilayer sample with In0.15Ga0.85As/GaAs capping shows the best result in terms of the peak emission wavelength of 1177nm, FWHM of 15.67nm and activation energy of 339meV compared to all the structures. Trilayer sample seems to be the optimum stacking having the best confinement resulting lower dark current density of 6.5E-8 A/cm2 measured at 100K. The sample also shows a multicolor response at ~4.89μm and at ~7.08μm in the mid infrared range. Further optimization of the spacer thickness and dot layer deposition can improve the response towards the long infrared range.
{"title":"Effect of varying capping composition and number of strain-coupled stacks on In0.5Ga0.5As quantum dot infrared photodetectors","authors":"D. Panda, S. Shetty, A. Balgarkashi, H. Ghadi, N. Sehara, S. Chakrabarti","doi":"10.1117/12.2209308","DOIUrl":"https://doi.org/10.1117/12.2209308","url":null,"abstract":"In this paper, we have reported the optical and electrical properties of strain coupled multi-stack quantum dot infrared photodetectors (QDIPs) of In0.5Ga0.5As dots with different capping compositions. Bilayer, trilayer, pentalayer and heptalayer coupled QDIPs are grown by solid source molecular beam epitaxy with one set of samples containing conventional GaAs capping (12nm) and second set containing a combinational capping of In0.15Ga0.85As (3nm) and GaAs (9nm) layers with same total thickness. The entire set of strain coupled quantum dots (QDs) shows a red shift in ground state photoluminescence peak in comparison to the uncoupled structures. Due to the reduction in indium interdiffusion from In0.5Ga0.5As dots in the combinational capped structures, a higher redshift is observed compared to the GaAs capped structures, which attributes larger dot size in the former ones. Full width half maximum value (FWHM) of In0.15Ga0.85As/GaAs capped QDs are lower, showing uniform distribution of dot size compared to the corresponding GaAs capped QDs. Trilayer sample with In0.15Ga0.85As/GaAs capping shows the best result in terms of the peak emission wavelength of 1177nm, FWHM of 15.67nm and activation energy of 339meV compared to all the structures. Trilayer sample seems to be the optimum stacking having the best confinement resulting lower dark current density of 6.5E-8 A/cm2 measured at 100K. The sample also shows a multicolor response at ~4.89μm and at ~7.08μm in the mid infrared range. Further optimization of the spacer thickness and dot layer deposition can improve the response towards the long infrared range.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114629878","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}
The high-speed, high-efficient, compact phase modulator array is indispensable in the Optical-phased array (OPA) which has been considered as a promising technology for realizing flexible and efficient beam steering. In our research, two methods are presented to utilize high-contrast grating (HCG) as high-efficient phase modulator. One is that HCG possesses high-Q resonances that origins from the cancellation of leaky waves. As a result, sharp resonance peaks appear on the reflection spectrum thus HCGs can be utilized as efficient phase shifters. Another is that low-Q mode HCG is utilized as ultra-lightweight mirror. With MEMS technology, small HCG displacement (~50 nm) leads to large phase change (~1.7π). Effective beam steering is achieved in Connie Chang-Hasnian’s group. On the other hand, we theoretically and experimentally investigate the system design for silicon-based optical phased array, including the star coupler, phased array, emission elements and far-field patterns. Further, the non-uniform optical phased array is presented.
{"title":"Progress and prospects of silicon-based design for optical phased array","authors":"Weiwei Hu, Chao Peng, C. Chang-Hasnain","doi":"10.1117/12.2214155","DOIUrl":"https://doi.org/10.1117/12.2214155","url":null,"abstract":"The high-speed, high-efficient, compact phase modulator array is indispensable in the Optical-phased array (OPA) which has been considered as a promising technology for realizing flexible and efficient beam steering. In our research, two methods are presented to utilize high-contrast grating (HCG) as high-efficient phase modulator. One is that HCG possesses high-Q resonances that origins from the cancellation of leaky waves. As a result, sharp resonance peaks appear on the reflection spectrum thus HCGs can be utilized as efficient phase shifters. Another is that low-Q mode HCG is utilized as ultra-lightweight mirror. With MEMS technology, small HCG displacement (~50 nm) leads to large phase change (~1.7π). Effective beam steering is achieved in Connie Chang-Hasnian’s group. On the other hand, we theoretically and experimentally investigate the system design for silicon-based optical phased array, including the star coupler, phased array, emission elements and far-field patterns. Further, the non-uniform optical phased array is presented.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114537774","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}
Lingjun Jiang, Stephen R. Anderson, H. Taleb, Z. Huang, Weimin Zhou
In this work, we have designed a novel Si based 1-dimensional high contrast meta-structure waveguide that has slow light effect as well as phase tunability using p-n junction. The goal is to use such waveguide to design active optical devices such as high frequency modulators and tunable filters for analog RF-photonics or data communication applications. The Si ridge waveguide has a pair of high contrast grating wings adhered to the waveguide core in the center. Grating bars at two sides of the waveguide are doped P and N-type respectively, while a p-n junction region is formed in the middle of the waveguide core. By applying a voltage to bias the p-n junction, one can sweep the free carriers to change the effective index of the waveguide as well as the dispersion property of the grating. This metastructure Si waveguide is ideal in the design of high frequency optical modulators since the slow light effect can reduce the modulator waveguide length, increase the modulation efficiency as well as compensate other nonlinearity factors of the modulator for analog applications.
{"title":"Active tunable high contrast meta-structure Si waveguide","authors":"Lingjun Jiang, Stephen R. Anderson, H. Taleb, Z. Huang, Weimin Zhou","doi":"10.1117/12.2216273","DOIUrl":"https://doi.org/10.1117/12.2216273","url":null,"abstract":"In this work, we have designed a novel Si based 1-dimensional high contrast meta-structure waveguide that has slow light effect as well as phase tunability using p-n junction. The goal is to use such waveguide to design active optical devices such as high frequency modulators and tunable filters for analog RF-photonics or data communication applications. The Si ridge waveguide has a pair of high contrast grating wings adhered to the waveguide core in the center. Grating bars at two sides of the waveguide are doped P and N-type respectively, while a p-n junction region is formed in the middle of the waveguide core. By applying a voltage to bias the p-n junction, one can sweep the free carriers to change the effective index of the waveguide as well as the dispersion property of the grating. This metastructure Si waveguide is ideal in the design of high frequency optical modulators since the slow light effect can reduce the modulator waveguide length, increase the modulation efficiency as well as compensate other nonlinearity factors of the modulator for analog applications.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115914799","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}
Z. Wang, Xiaochuan Xu, D. Fan, Yaguo Wang, Ray T. Chen
In recent decades, silicon photonics has attracted intensive research interest in optical communications due to its advantageous compact dimensions and high-volume manufacturability. Particularly, micro-ring resonators on silicon-oninsulator (SOI) platform have been widely exploited as a basic building block for a vast range of applications such as switches, modulators, and sensors. A majority of these applications involve light-matter interaction, which can be substantially enhanced by the high quality factor micro-ring resonators. However, conventional strip waveguide based micro-ring resonators suffer from the intrinsic dilemma in achieving high light confinement and strong light-matter interaction simultaneously. Subwavelength grating (SWG) waveguides, comprised of periodically interleaved high and low refractive index materials with a pitch less than one wavelength, have been demonstrated as a promising alternative. For SWG waveguides built on SOI wafers, the ratio of silicon and cladding materials can be engineered microscopically to achieve desired macroscopic properties. The control of these properties could potentially lead to significant performance improvements compared with conventional micro-ring resonators based photonic devices, such as filters and sensors. However, SWG waveguide based micro-ring resonators (SWGMRs) that have been demonstrated so far can only provide a moderate quality factor (~5600) with a large radius (e.g. 15 μm), which greatly jeopardize the wide spread research efforts in this area. In this paper, we propose to use trapezoidal silicon pillars to reduce the bend loss of SWGMRs to improve the quality factor. For the first time, we experimentally demonstrate the smallest SWGMR (the micro-ring radius equals to 5 μm) with an applicable quality factor as high as 11,500. This approach also can be applied to SWGMRs with larger radii for higher quality factors. We also experimentally demonstrated a 10 μm radius SWGMR that can provide a quality factor up to 45,000. Compared to SWGMRs built with conventional rectangular silicon pillars, the quality factors is increased by 4.6 times from a 5 μm radius SWGMR and 3 times from a 10 μm SWGMR radius, respectively.
{"title":"High quality factor trapezoidal subwavelength grating waveguide micro-ring resonator","authors":"Z. Wang, Xiaochuan Xu, D. Fan, Yaguo Wang, Ray T. Chen","doi":"10.1117/12.2213935","DOIUrl":"https://doi.org/10.1117/12.2213935","url":null,"abstract":"In recent decades, silicon photonics has attracted intensive research interest in optical communications due to its advantageous compact dimensions and high-volume manufacturability. Particularly, micro-ring resonators on silicon-oninsulator (SOI) platform have been widely exploited as a basic building block for a vast range of applications such as switches, modulators, and sensors. A majority of these applications involve light-matter interaction, which can be substantially enhanced by the high quality factor micro-ring resonators. However, conventional strip waveguide based micro-ring resonators suffer from the intrinsic dilemma in achieving high light confinement and strong light-matter interaction simultaneously. Subwavelength grating (SWG) waveguides, comprised of periodically interleaved high and low refractive index materials with a pitch less than one wavelength, have been demonstrated as a promising alternative. For SWG waveguides built on SOI wafers, the ratio of silicon and cladding materials can be engineered microscopically to achieve desired macroscopic properties. The control of these properties could potentially lead to significant performance improvements compared with conventional micro-ring resonators based photonic devices, such as filters and sensors. However, SWG waveguide based micro-ring resonators (SWGMRs) that have been demonstrated so far can only provide a moderate quality factor (~5600) with a large radius (e.g. 15 μm), which greatly jeopardize the wide spread research efforts in this area. In this paper, we propose to use trapezoidal silicon pillars to reduce the bend loss of SWGMRs to improve the quality factor. For the first time, we experimentally demonstrate the smallest SWGMR (the micro-ring radius equals to 5 μm) with an applicable quality factor as high as 11,500. This approach also can be applied to SWGMRs with larger radii for higher quality factors. We also experimentally demonstrated a 10 μm radius SWGMR that can provide a quality factor up to 45,000. Compared to SWGMRs built with conventional rectangular silicon pillars, the quality factors is increased by 4.6 times from a 5 μm radius SWGMR and 3 times from a 10 μm SWGMR radius, respectively.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115390813","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}
Fast scanning is highly desired for both ultrasound and photoacoustic microscopic imaging. Limited by water environment required for acoustic propagation, traditional mircoelectromechanical system (MEMS) scanning mirrors could not be widely used. In this paper, a new water-immersible scanning mirror microsystem has been designed, fabricated and tested. Polymer hinges were employed to achieve reliable under water performance. Two pairs of high strength neodymium magnet disc and three compact RF choke inductor were used to actuate mirror module. Experimental results show that the fast axis can reach a mechanical scanning angle of ±15° at the resonance frequency of 350 Hz in air, and ±12.5° at the resonance frequency of 240 Hz in water, respectively. The slow axis can reach a mechanical scanning angle of ±15° at the resonance frequency of 20 Hz in air, and ±12.5° at the resonance frequency of 13 Hz in water, respectively. The two scanning axes have very different resonance frequencies, which are suitable for raster scanning.
{"title":"A two-axis water-immersible MEMS scanning mirror for scanning optical and acoustic microscopy","authors":"Song Xu, Chih-Hsien Huang, J. Zou","doi":"10.1117/12.2211752","DOIUrl":"https://doi.org/10.1117/12.2211752","url":null,"abstract":"Fast scanning is highly desired for both ultrasound and photoacoustic microscopic imaging. Limited by water environment required for acoustic propagation, traditional mircoelectromechanical system (MEMS) scanning mirrors could not be widely used. In this paper, a new water-immersible scanning mirror microsystem has been designed, fabricated and tested. Polymer hinges were employed to achieve reliable under water performance. Two pairs of high strength neodymium magnet disc and three compact RF choke inductor were used to actuate mirror module. Experimental results show that the fast axis can reach a mechanical scanning angle of ±15° at the resonance frequency of 350 Hz in air, and ±12.5° at the resonance frequency of 240 Hz in water, respectively. The slow axis can reach a mechanical scanning angle of ±15° at the resonance frequency of 20 Hz in air, and ±12.5° at the resonance frequency of 13 Hz in water, respectively. The two scanning axes have very different resonance frequencies, which are suitable for raster scanning.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"690 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124719902","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}
Traffic in data centers networks (DCNs) is steadily growing to support various applications and virtualization technologies. Multi-tenancy enabling efficient resource utilization is considered as a key requirement for the next generation DCs resulting from the growing demands for services and applications. Virtualization mechanisms and technologies can leverage statistical multiplexing and fast switch reconfiguration to further extend the DC efficiency and agility. We present a novel high performance flat DCN employing bufferless and distributed fast (sub-microsecond) optical switches with wavelength, space, and time switching operation. The fast optical switches can enhance the performance of the DCNs by providing large-capacity switching capability and efficiently sharing the data plane resources by exploiting statistical multiplexing. Benefiting from the Software-Defined Networking (SDN) control of the optical switches, virtual DCNs can be flexibly created and reconfigured by the DCN provider. Numerical and experimental investigations of the DCN based on the fast optical switches show the successful setup of virtual network slices for intra-data center interconnections. Experimental results to assess the DCN performance in terms of latency and packet loss show less than 10^-5 packet loss and 640ns end-to-end latency with 0.4 load and 16- packet size buffer. Numerical investigation on the performance of the systems when the port number of the optical switch is scaled to 32x32 system indicate that more than 1000 ToRs each with Terabit/s interface can be interconnected providing a Petabit/s capacity. The roadmap to photonic integration of large port optical switches will be also presented.
{"title":"High-performance flat data center network architecture based on scalable and flow-controlled optical switching system","authors":"N. Calabretta, W. Miao, H. Dorren","doi":"10.1117/12.2205231","DOIUrl":"https://doi.org/10.1117/12.2205231","url":null,"abstract":"Traffic in data centers networks (DCNs) is steadily growing to support various applications and virtualization technologies. Multi-tenancy enabling efficient resource utilization is considered as a key requirement for the next generation DCs resulting from the growing demands for services and applications. Virtualization mechanisms and technologies can leverage statistical multiplexing and fast switch reconfiguration to further extend the DC efficiency and agility. We present a novel high performance flat DCN employing bufferless and distributed fast (sub-microsecond) optical switches with wavelength, space, and time switching operation. The fast optical switches can enhance the performance of the DCNs by providing large-capacity switching capability and efficiently sharing the data plane resources by exploiting statistical multiplexing. Benefiting from the Software-Defined Networking (SDN) control of the optical switches, virtual DCNs can be flexibly created and reconfigured by the DCN provider. Numerical and experimental investigations of the DCN based on the fast optical switches show the successful setup of virtual network slices for intra-data center interconnections. Experimental results to assess the DCN performance in terms of latency and packet loss show less than 10^-5 packet loss and 640ns end-to-end latency with 0.4 load and 16- packet size buffer. Numerical investigation on the performance of the systems when the port number of the optical switch is scaled to 32x32 system indicate that more than 1000 ToRs each with Terabit/s interface can be interconnected providing a Petabit/s capacity. The roadmap to photonic integration of large port optical switches will be also presented.","PeriodicalId":122702,"journal":{"name":"SPIE OPTO","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124863948","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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