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Govind P Agrawal - One of the best experts on this subject based on the ideXlab platform.
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mid infrared supercontinuum generation using dispersion engineered ge 11 5 as 24 se 64 5 chalcogenide channel waveguide
Optics Express, 2015Co-Authors: Mohammad Rezaul Karim, B. M. A. Rahman, Govind P AgrawalAbstract:We numerically investigate mid-infrared supercontinuum (SC) generation in dispersion-engineered, air-clad, Ge11.5As24Se64.5 chalcogenide-glass channel waveguides employing two different materials, Ge11.5As24S64.5 or MgF2 glass for their lower cladding. We study the effect of waveguide parameters on the bandwidth of the SC at the output of 1-cm-long waveguide. Our results show that output can vary over a wide range depending on its design and the pump wavelength employed. At the pump wavelength of 2 μm the SC never extended beyond 4.5 μm for any of our designs. However, supercontinuum could be extended to beyond 5 μm for a pump wavelength of 3.1 μm. A broadband SC spanning from 2 μm to 6 μm and extending over 1.5 Octave could be generated with a moderate peak power of 500 W at a pump wavelength of 3.1 μm using an air-clad, all-chalcogenide, channel waveguide. We show that SC can be extended even further when MgF2 glass is used for the lower cladding of chalcogenide waveguide. Our numerical simulations produced SC spectra covering the wavelength range 1.8–7.7 μm (> two Octaves) by using this geometry. Both ranges exceed the broadest SC bandwidths reported so far. Moreover, we realize it using 3.1 μm pump source and relatively low peak power pulses. By employing the same pump source, we show that SC spectra can cover a wavelength range of 1.8–11 μm (> 2.5 Octaves) in a channel waveguide employing MgF2 glass for its lower cladding with a moderate peak power of 3000 W.
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mid infrared supercontinuum generation using dispersion engineered ge 11 5 as 24 se 64 5 chalcogenide channel waveguide
Optics Express, 2015Co-Authors: Mohammad Rezaul Karim, B. M. A. Rahman, Govind P AgrawalAbstract:We numerically investigate mid-infrared supercontinuum (SC) generation in dispersion-engineered, air-clad, Ge(11.5)As(24)Se(64.5) chalcogenide-glass channel waveguides employing two different materials, Ge(11.5)As(24)Se(64.5) or MgF(2) glass for their lower cladding. We study the effect of waveguide parameters on the bandwidth of the SC at the output of 1-cm-long waveguide. Our results show that output can vary over a wide range depending on its design and the pump wavelength employed. At the pump wavelength of 2 μm the SC never extended beyond 4.5 μm for any of our designs. However, supercontinuum could be extended to beyond 5 μm for a pump wavelength of 3.1 μm. A broadband SC spanning from 2 μm to 6 μm and extending over 1.5 Octave could be generated with a moderate peak power of 500 W at a pump wavelength of 3.1 μm using an air-clad, all-chalcogenide, channel waveguide. We show that SC can be extended even further when MgF(2) glass is used for the lower cladding of chalcogenide waveguide. Our numerical simulations produced SC spectra covering the wavelength range 1.8-7.7 μm (> two Octaves) by using this geometry. Both ranges exceed the broadest SC bandwidths reported so far. Moreover, we realize it using 3.1 μm pump source and relatively low peak power pulses. By employing the same pump source, we show that SC spectra can cover a wavelength range of 1.8-11 μm (> 2.5 Octaves) in a channel waveguide employing MgF(2) glass for its lower cladding with a moderate peak power of 3000 W.
Mohammad Rezaul Karim - One of the best experts on this subject based on the ideXlab platform.
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mid infrared supercontinuum generation using dispersion engineered ge 11 5 as 24 se 64 5 chalcogenide channel waveguide
Optics Express, 2015Co-Authors: Mohammad Rezaul Karim, B. M. A. Rahman, Govind P AgrawalAbstract:We numerically investigate mid-infrared supercontinuum (SC) generation in dispersion-engineered, air-clad, Ge11.5As24Se64.5 chalcogenide-glass channel waveguides employing two different materials, Ge11.5As24S64.5 or MgF2 glass for their lower cladding. We study the effect of waveguide parameters on the bandwidth of the SC at the output of 1-cm-long waveguide. Our results show that output can vary over a wide range depending on its design and the pump wavelength employed. At the pump wavelength of 2 μm the SC never extended beyond 4.5 μm for any of our designs. However, supercontinuum could be extended to beyond 5 μm for a pump wavelength of 3.1 μm. A broadband SC spanning from 2 μm to 6 μm and extending over 1.5 Octave could be generated with a moderate peak power of 500 W at a pump wavelength of 3.1 μm using an air-clad, all-chalcogenide, channel waveguide. We show that SC can be extended even further when MgF2 glass is used for the lower cladding of chalcogenide waveguide. Our numerical simulations produced SC spectra covering the wavelength range 1.8–7.7 μm (> two Octaves) by using this geometry. Both ranges exceed the broadest SC bandwidths reported so far. Moreover, we realize it using 3.1 μm pump source and relatively low peak power pulses. By employing the same pump source, we show that SC spectra can cover a wavelength range of 1.8–11 μm (> 2.5 Octaves) in a channel waveguide employing MgF2 glass for its lower cladding with a moderate peak power of 3000 W.
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mid infrared supercontinuum generation using dispersion engineered ge 11 5 as 24 se 64 5 chalcogenide channel waveguide
Optics Express, 2015Co-Authors: Mohammad Rezaul Karim, B. M. A. Rahman, Govind P AgrawalAbstract:We numerically investigate mid-infrared supercontinuum (SC) generation in dispersion-engineered, air-clad, Ge(11.5)As(24)Se(64.5) chalcogenide-glass channel waveguides employing two different materials, Ge(11.5)As(24)Se(64.5) or MgF(2) glass for their lower cladding. We study the effect of waveguide parameters on the bandwidth of the SC at the output of 1-cm-long waveguide. Our results show that output can vary over a wide range depending on its design and the pump wavelength employed. At the pump wavelength of 2 μm the SC never extended beyond 4.5 μm for any of our designs. However, supercontinuum could be extended to beyond 5 μm for a pump wavelength of 3.1 μm. A broadband SC spanning from 2 μm to 6 μm and extending over 1.5 Octave could be generated with a moderate peak power of 500 W at a pump wavelength of 3.1 μm using an air-clad, all-chalcogenide, channel waveguide. We show that SC can be extended even further when MgF(2) glass is used for the lower cladding of chalcogenide waveguide. Our numerical simulations produced SC spectra covering the wavelength range 1.8-7.7 μm (> two Octaves) by using this geometry. Both ranges exceed the broadest SC bandwidths reported so far. Moreover, we realize it using 3.1 μm pump source and relatively low peak power pulses. By employing the same pump source, we show that SC spectra can cover a wavelength range of 1.8-11 μm (> 2.5 Octaves) in a channel waveguide employing MgF(2) glass for its lower cladding with a moderate peak power of 3000 W.
B. M. A. Rahman - One of the best experts on this subject based on the ideXlab platform.
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mid infrared supercontinuum generation using dispersion engineered ge 11 5 as 24 se 64 5 chalcogenide channel waveguide
Optics Express, 2015Co-Authors: Mohammad Rezaul Karim, B. M. A. Rahman, Govind P AgrawalAbstract:We numerically investigate mid-infrared supercontinuum (SC) generation in dispersion-engineered, air-clad, Ge11.5As24Se64.5 chalcogenide-glass channel waveguides employing two different materials, Ge11.5As24S64.5 or MgF2 glass for their lower cladding. We study the effect of waveguide parameters on the bandwidth of the SC at the output of 1-cm-long waveguide. Our results show that output can vary over a wide range depending on its design and the pump wavelength employed. At the pump wavelength of 2 μm the SC never extended beyond 4.5 μm for any of our designs. However, supercontinuum could be extended to beyond 5 μm for a pump wavelength of 3.1 μm. A broadband SC spanning from 2 μm to 6 μm and extending over 1.5 Octave could be generated with a moderate peak power of 500 W at a pump wavelength of 3.1 μm using an air-clad, all-chalcogenide, channel waveguide. We show that SC can be extended even further when MgF2 glass is used for the lower cladding of chalcogenide waveguide. Our numerical simulations produced SC spectra covering the wavelength range 1.8–7.7 μm (> two Octaves) by using this geometry. Both ranges exceed the broadest SC bandwidths reported so far. Moreover, we realize it using 3.1 μm pump source and relatively low peak power pulses. By employing the same pump source, we show that SC spectra can cover a wavelength range of 1.8–11 μm (> 2.5 Octaves) in a channel waveguide employing MgF2 glass for its lower cladding with a moderate peak power of 3000 W.
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mid infrared supercontinuum generation using dispersion engineered ge 11 5 as 24 se 64 5 chalcogenide channel waveguide
Optics Express, 2015Co-Authors: Mohammad Rezaul Karim, B. M. A. Rahman, Govind P AgrawalAbstract:We numerically investigate mid-infrared supercontinuum (SC) generation in dispersion-engineered, air-clad, Ge(11.5)As(24)Se(64.5) chalcogenide-glass channel waveguides employing two different materials, Ge(11.5)As(24)Se(64.5) or MgF(2) glass for their lower cladding. We study the effect of waveguide parameters on the bandwidth of the SC at the output of 1-cm-long waveguide. Our results show that output can vary over a wide range depending on its design and the pump wavelength employed. At the pump wavelength of 2 μm the SC never extended beyond 4.5 μm for any of our designs. However, supercontinuum could be extended to beyond 5 μm for a pump wavelength of 3.1 μm. A broadband SC spanning from 2 μm to 6 μm and extending over 1.5 Octave could be generated with a moderate peak power of 500 W at a pump wavelength of 3.1 μm using an air-clad, all-chalcogenide, channel waveguide. We show that SC can be extended even further when MgF(2) glass is used for the lower cladding of chalcogenide waveguide. Our numerical simulations produced SC spectra covering the wavelength range 1.8-7.7 μm (> two Octaves) by using this geometry. Both ranges exceed the broadest SC bandwidths reported so far. Moreover, we realize it using 3.1 μm pump source and relatively low peak power pulses. By employing the same pump source, we show that SC spectra can cover a wavelength range of 1.8-11 μm (> 2.5 Octaves) in a channel waveguide employing MgF(2) glass for its lower cladding with a moderate peak power of 3000 W.
Kartik Srinivasan - One of the best experts on this subject based on the ideXlab platform.
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broadband resonator waveguide coupling for efficient extraction of Octave spanning microcombs
Optics Letters, 2019Co-Authors: Gregory Moille, Travis C Briles, Tara E Drake, Ashutosh Rao, Daron A Westly, Scott B Papp, Kartik SrinivasanAbstract:Octave-spanning frequency combs have been successfully demonstrated in Kerr nonlinear microresonators. These microcombs rely on both engineered dispersion, to enable generation of frequency components across the Octave, and on engineered coupling, to efficiently extract the generated light into an access waveguide while maintaining a close to critically coupled pump. The latter is challenging, as the spatial overlap between the access waveguide and the ring modes decays with frequency. This leads to strong coupling variation across the Octave, with poor extraction at short wavelengths. Here, we investigate how a waveguide wrapped around a portion of the resonator, in a pulley scheme, can improve the extraction of Octave-spanning microcombs, in particular at short wavelengths. We use the coupled-mode theory to predict the performance of the pulley couplers and demonstrate good agreement with experimental measurements. Using an optimal pulley coupling design, we demonstrate a 20 dB improvement in extraction at short wavelengths compared to straight waveguide coupling.
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broadband resonator waveguide coupling for efficient extraction of Octave spanning microcombs
arXiv: Optics, 2019Co-Authors: Gregory Moille, Travis C Briles, Tara E Drake, Ashutosh Rao, Daron A Westly, Scott B Papp, Kartik SrinivasanAbstract:Frequency combs spanning over an Octave have been successfully demonstrated in Kerr nonlinear microresonators on-chip. These micro-combs rely on both engineered dispersion, to enable generation of frequency components across the Octave, and on engineered coupling, to efficiently extract the generated light into an access waveguide while maintaining a close to critically-coupled pump. The latter is challenging as the spatial overlap between the access waveguide and the ring modes decays with frequency. This leads to strong coupling variation across the Octave, with poor extraction at short wavelengths. Here, we investigate how a waveguide wrapped around a portion of the resonator, in a pulley scheme, can improve extraction of Octave-spanning microcombs, in particular at short wavelengths. We use coupled mode theory to predict the performance of the pulley couplers, and demonstrate good agreement with experimental measurements. Using an optimal pulley coupling design, we demonstrate a 20~dB improvement in extraction at short wavelengths compared to straight waveguide coupling.
Andrew Stua - One of the best experts on this subject based on the ideXlab platform.
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neonate auditory brainstem responses to ce chirp and ce chirp Octave band stimuli i versus click and tone burst stimuli
Ear and Hearing, 2016Co-Authors: Kensi M Cobb, Andrew StuaAbstract:OBJECTIVES The purpose of the study was to generate normative auditory brainstem response (ABR) wave component peak latency and amplitude values for neonates with air- and bone-conducted CE-Chirps and air-conducted CE-Chirp Octave band stimuli (i.e., 500, 1000, 2000, and 4000 Hz). A second objective was to compare neonate ABRs to CE-Chirp stimuli with ABR responses to traditional click and tone burst stimuli with the same stimulus parameters. DESIGN Participants were 168 healthy neonates. ABRs were obtained to air- and bone-conducted CE-Chirp and click stimuli and air-conducted CE-Chirp Octave band and tone burst stimuli. The effects of stimulus level, rate, and polarity were examined with air-conducted CE-Chirps and clicks. The effect of stimulus level was also examined with bone-conducted CE-Chirps and clicks and air-conducted CE-Chirp Octave band stimuli. RESULTS In general, ABR wave V amplitudes to air- and bone-conducted CE-Chirp stimuli were significantly larger (p < 0.05) than those evoked to traditional click and tone burst stimuli. Systematic statistically significant (p < 0.05) wave V latency differences existed between the air- and bone-conducted CE-Chirp and CE-Chirp Octave band stimuli relative to traditional click and tone burst stimuli. CONCLUSIONS ABRs to air- and bone-conducted CE-Chirps and CE-Chirp Octave band stimuli may be valuable in the assessment of newborn infants. However, the prognostic value of such stimuli needs to be validated.
