The Experts below are selected from a list of 7887 Experts worldwide ranked by ideXlab platform
Xuxing Chen - One of the best experts on this subject based on the ideXlab platform.
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High Channel-Count Ultra-Narrow Comb-Filter Based on a Triply Sampled Fiber Bragg Grating
IEEE Photonics Technology Letters, 2014Co-Authors: Hongpu Li, Xuxing ChenAbstract:Based on a sampled fiber Bragg grating (FBG) with simultaneous utilization of two amplitude-assisted phase sampling functions and a phase-only sampling (POS) function, a novel comb filter that has a high Channel Count and an excellent Channel uniformity is first proposed. With the proposed method, an ultra-narrow FBG-based filter with consecutive 1377 Channels, a Channel bandwidth of 1.5 GHz, and a Channel spacing of 25 GHz is theoretically demonstrated.
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High Channel-Count ultra-narrow comb-filter based on a sampled fiber Bragg grating
2011Co-Authors: Xuxing ChenAbstract:An ultra-narrow comb-filter formed by a piezoelectric transducer (PZT)-induced phase-shift in a phase-only sampled FBG is proposed and experimentally demonstrated. Moreover, the high Channel-Count scheme based on a triply sampled FBG is firstly proposed.
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Ultrahigh-Channel-Count fiber Bragg grating based on the triple sampling method
Optics Communications, 2011Co-Authors: Xuxing Chen, Junya HayashiAbstract:Abstract A triple sampling method to have enabled excellent Channel uniformity and high in-band energy efficiency is firstly proposed for the design of an ultrahigh-Channel-Count fiber Bragg grating (FBG), which is based on the simultaneous utilization of two amplitude-assisted phase sampling (AAPS) functions and a phase-only sampling (POS) function. As an example, one linearly chirped FBG with consecutive 1215 Channels enabling to cover all fiber telecom bands (O + E + S + C + L + U) is numerically demonstrated, which has a length of 9 cm, a dispersion of − 1360 ps/nm, and a Channel spacing of 50 GHz. The maximum index-change required for 10 dB strength of the FBG is less than 6 × 10 − 3 .
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Ultra-high Channel-Count fiber Bragg grating based on the utilization of the phase-only sampling
Holography Diffractive Optics and Applications IV, 2010Co-Authors: Xuxing ChenAbstract:As one of the fiber-based wide-band promising components, high Channel-Count fiber Bragg grating has recently attracted great interests. In this paper, we introduce our recent developments in the design techniques for the ultra-high Channel-Count fiber Bragg gratings (FBG). The key technique is based on the utilization of a continuous phase-only sampling, which is the same as the one for the optimization of a phase-only grating in the diffractive optics. With the proposed sampling method, we have theoretically demonstrated a novel doubly sampled FBG with Channels up to 405, which could be used as either the dispersion compensator or the comb filter in broad-band wavelength-division multiplexing (WDM) system.
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Advanced design of the ultrahigh-Channel-Count fiber Bragg grating based on the double sampling method
Optics express, 2009Co-Authors: Xuxing Chen, Junya HayashiAbstract:A double sampling method enabling to have excellent Channel uniformity and high in-band energy efficiency is firstly proposed for the design of an ultrahigh-Channel-Count fiber Bragg grating (FBG), which is based on the simultaneously utilization of an amplitude-assisted phase sampling (AAPS) function and a phase-only sampling (POS) function. As examples, two typical 10-dB FBGs with a length of 12 cm, dispersion of - 1360ps/nm, Channel spacing of 0.8 nm, and a consecutive 135- and 405- Channels are numerically designed. The maximum index-modulations required are about 0.8×10-3, and 1.3×10-3, respectively. Compared with the proposed method, the other two kinds of double sampling schemes by utilizing either the double AAPS (i.e., AAPS+AAPS) or the double POS (i.e., POS+POS) have also been introduced for the design of the multiChannel FBGs. Fabrication tolerances to the designed 135-Channel FBG obtained with the AAPS plus POS method are numerically investigated.
Andrew J Mason - One of the best experts on this subject based on the ideXlab platform.
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microfabricated capacitive electrodes for high Channel Count ecog recording
International IEEE EMBS Conference on Neural Engineering, 2019Co-Authors: Heyu Yin, Ehsan Ashoori, Sina Parsnejad, Joseph W Salatino, Erin K Purcell, Andrew J MasonAbstract:Toward understanding brain functionality, high Channel Count ECoG arrays enable expanding the resolution and/or physical scope of neural recordings. For fully implanted ECoG arrays, one limiting factor to scaling Channel Count is the size of the front-end recording electronics, which is dominated by the coupling capacitor needed at every recording Channel. This paper presents an ECoG array with coupling capacitors fabricated into the electrodes that significantly reduces the area required for recording electronics and thus enables scaling to higher Channel Counts. Two different fabrication procedures were explored to form 4x4 arrays of 8 pF capacitor-embedded electrodes utilizing a stack of Cu, Ta2O5, and Ti/Au on a flexible substrate. Several in vivo experiments were performed on an adult rat, and physiologically evoked activity was successfully observed for shoulder and hindlimb tapping as well as for whisker deflection.
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NER - Microfabricated Capacitive Electrodes for High Channel Count ECoG Recording
2019 9th International IEEE EMBS Conference on Neural Engineering (NER), 2019Co-Authors: Heyu Yin, Ehsan Ashoori, Sina Parsnejad, Joseph W Salatino, Erin K Purcell, Andrew J MasonAbstract:Toward understanding brain functionality, high Channel Count ECoG arrays enable expanding the resolution and/or physical scope of neural recordings. For fully implanted ECoG arrays, one limiting factor to scaling Channel Count is the size of the front-end recording electronics, which is dominated by the coupling capacitor needed at every recording Channel. This paper presents an ECoG array with coupling capacitors fabricated into the electrodes that significantly reduces the area required for recording electronics and thus enables scaling to higher Channel Counts. Two different fabrication procedures were explored to form 4x4 arrays of 8 pF capacitor-embedded electrodes utilizing a stack of Cu, Ta2O5, and Ti/Au on a flexible substrate. Several in vivo experiments were performed on an adult rat, and physiologically evoked activity was successfully observed for shoulder and hindlimb tapping as well as for whisker deflection.
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compact and low power analog front end with in situ data decimator for high Channel Count ecog recording
International Symposium on Circuits and Systems, 2018Co-Authors: Ehsan Ashoori, Sylmarie Davilamontero, Andrew J MasonAbstract:High Channel Count neural implants that can record brain activities across diverse cortical regions represent the next step toward whole brain interfaces that will enable new understanding of brain operation and treatment of many neural disorders. To overcome the size and power constraints limiting the Channel Count of existing neural implants, this paper presents a new neural amplifier array design that utilizes hardware sharing to achieve low power and compact size. Moreover, to ease the burden of large volume data handling, in-situ data decimation is performed to enable off body evaluation of synchrony between signal pairs. A 32-Channel analog front end array was designed and post-layout simulations show that the entire front end occupies only 0.031 mm2 per Channel while consuming only 3.34 μW per Channel at 3.3 V in 0.5 μm CMOS. This front end decimates data by an order of magnitude while keeping the synchrony information with more than 89.1% accuracy.
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ISCAS - Compact and Low Power Analog Front End with in-situ Data Decimator for High-Channel-Count ECoG Recording
2018 IEEE International Symposium on Circuits and Systems (ISCAS), 2018Co-Authors: Ehsan Ashoori, Sylmarie Davila-montero, Andrew J MasonAbstract:High Channel Count neural implants that can record brain activities across diverse cortical regions represent the next step toward whole brain interfaces that will enable new understanding of brain operation and treatment of many neural disorders. To overcome the size and power constraints limiting the Channel Count of existing neural implants, this paper presents a new neural amplifier array design that utilizes hardware sharing to achieve low power and compact size. Moreover, to ease the burden of large volume data handling, in-situ data decimation is performed to enable off body evaluation of synchrony between signal pairs. A 32-Channel analog front end array was designed and post-layout simulations show that the entire front end occupies only 0.031 mm2 per Channel while consuming only 3.34 μW per Channel at 3.3 V in 0.5 μm CMOS. This front end decimates data by an order of magnitude while keeping the synchrony information with more than 89.1% accuracy.
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BioCAS - ECoG Electrode Array with Embedded Coupling Capacitors for Area Efficient Neural Recording
2018 IEEE Biomedical Circuits and Systems Conference (BioCAS), 2018Co-Authors: Ehsan Ashoori, Heyu Yin, Sina Parsnejad, Joseph W Salatino, Erin K Purcell, Andrew J MasonAbstract:ECoG electrode arrays offer great potential for high-Channel-Count monitoring of large scale brain activity. However, scaling ECoG recording systems to high Channel Count is challenging due to the large silicon area demanded by the coupling capacitors necessary for DC offset voltage rejection. This paper presents a new approach to reduce the per-Channel area of recording circuits by introducing a capacitor-embedded ECoG electrode structure that implements coupling capacitors within the existing electrode area. For proof of concept, a 4×4 array of 8 pF capacitor-embedded electrodes was fabricated in a 2mm × 2mm area using a three-mask process to form a capacitor stack of Cu, Ta 2 O 5 , and Ti/Cu/ Au. In vivo experiments performed on an adult rat show that physiologically-evoked activity was accurately detected according to the placement of the electrodes for manual whisker deflection, shoulder tapping and hindlimb tapping. The capacitor-embedded ECoG electrode structure provides a new method for achieving high Channel Count neural recording.
Junya Hayashi - One of the best experts on this subject based on the ideXlab platform.
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Ultrahigh-Channel-Count fiber Bragg grating based on the triple sampling method
Optics Communications, 2011Co-Authors: Xuxing Chen, Junya HayashiAbstract:Abstract A triple sampling method to have enabled excellent Channel uniformity and high in-band energy efficiency is firstly proposed for the design of an ultrahigh-Channel-Count fiber Bragg grating (FBG), which is based on the simultaneous utilization of two amplitude-assisted phase sampling (AAPS) functions and a phase-only sampling (POS) function. As an example, one linearly chirped FBG with consecutive 1215 Channels enabling to cover all fiber telecom bands (O + E + S + C + L + U) is numerically demonstrated, which has a length of 9 cm, a dispersion of − 1360 ps/nm, and a Channel spacing of 50 GHz. The maximum index-change required for 10 dB strength of the FBG is less than 6 × 10 − 3 .
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Advanced design of the ultrahigh-Channel-Count fiber Bragg grating based on the double sampling method
Optics express, 2009Co-Authors: Xuxing Chen, Junya HayashiAbstract:A double sampling method enabling to have excellent Channel uniformity and high in-band energy efficiency is firstly proposed for the design of an ultrahigh-Channel-Count fiber Bragg grating (FBG), which is based on the simultaneously utilization of an amplitude-assisted phase sampling (AAPS) function and a phase-only sampling (POS) function. As examples, two typical 10-dB FBGs with a length of 12 cm, dispersion of - 1360ps/nm, Channel spacing of 0.8 nm, and a consecutive 135- and 405- Channels are numerically designed. The maximum index-modulations required are about 0.8×10-3, and 1.3×10-3, respectively. Compared with the proposed method, the other two kinds of double sampling schemes by utilizing either the double AAPS (i.e., AAPS+AAPS) or the double POS (i.e., POS+POS) have also been introduced for the design of the multiChannel FBGs. Fabrication tolerances to the designed 135-Channel FBG obtained with the AAPS plus POS method are numerically investigated.
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Ultrahigh-Channel-Count phase-only sampled fiber Bragg grating covering the S, C, and L bands
Optics letters, 2009Co-Authors: Junya HayashiAbstract:A continuous phase-only sampling scheme enabling one to create an ultrahigh-Channel-Count fiber Bragg grating (FBG) with excellent Channel uniformity and high in-band energy efficiency is proposed that is based on the simultaneous utilization of two phase-only sampling functions. With this method, a linearly chirped 135-Channel FBG with a length of 10 cm, a dispersion of 1360 ps/nm, Channel spacing of 0.8 nm, and grating strength of 10 dB is theoretically demonstrated, and the maximum refractive index change required is less than 10−3.
Hongpu Li - One of the best experts on this subject based on the ideXlab platform.
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High Channel-Count Ultra-Narrow Comb-Filter Based on a Triply Sampled Fiber Bragg Grating
IEEE Photonics Technology Letters, 2014Co-Authors: Hongpu Li, Xuxing ChenAbstract:Based on a sampled fiber Bragg grating (FBG) with simultaneous utilization of two amplitude-assisted phase sampling functions and a phase-only sampling (POS) function, a novel comb filter that has a high Channel Count and an excellent Channel uniformity is first proposed. With the proposed method, an ultra-narrow FBG-based filter with consecutive 1377 Channels, a Channel bandwidth of 1.5 GHz, and a Channel spacing of 25 GHz is theoretically demonstrated.
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advances in the design and fabrication of high Channel Count fiber bragg gratings
Journal of Lightwave Technology, 2007Co-Authors: Hongpu Li, Yunlong Sheng, Ming Li, Joshua E RothenbergAbstract:In this paper, we review our recent developments in the design and fabrication techniques for high-Channel-Count fiber Bragg gratings (FBGs). We have presented a theory for the phase-only sampled FBG and demonstrated that a sampled FBG of N Channels would require radicN/etamiddot times higher maximum reflective index modulation than that of the single-Channel FBG. We experimentally demonstrate a 45- and 81-Channel linearly chirped FBG for nearly whole C-band dispersion compensation, which is fabricated with a novel diffraction precompensated phase mask. The grating specifications obtained agree well with the theoretical design. We have presented a novel method for multiChannel FBG design, which enables us to design any kind of multiChannel FBGs, where the spectrum response of each Channel could be either identical or nonidentical. Particularly, the nine-Channel nonlinearly chirped FBG, which is used as a simultaneous dispersion and dispersion slope compensator, has been demonstrated.
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phased only sampled fiber bragg gratings for high Channel Count chromatic dispersion compensation
Journal of Lightwave Technology, 2003Co-Authors: Hongpu Li, Yunlong Sheng, Yao Li, Joshua E RothenbergAbstract:Binary and multilevel phase-only sampling functions are proposed for the sampled fiber Bragg gratings (FBGs) with high Channel Count, which require significantly less refractive-index modulation than that does the sampled grating with amplitude sampling. The design using the new simulated quenching optimization with temperature rescaling results in high Channel uniformity and minimum energy in the out-of-band Channels. The technique can be applied to the sampled FBGs with very high Channel Count. A five-Channel nonlinearly chirped multilevel phase-only sampled FBG for tunable chromatic dispersion compensation is demonstrated.
John E Bowers - One of the best experts on this subject based on the ideXlab platform.
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high resolution high Channel Count mid infrared arrayed waveguide gratings in silicon
Optics Letters, 2020Co-Authors: Aditya Malik, Alexander Spott, Yue Wang, Eric J Stanton, Jon Peters, John E BowersAbstract:Arrayed waveguide gratings (AWGs) working in the 4.7 µm wavelength range are reported on silicon-on-insulator waveguides with 1500 nm thick silicon and 2 µm thick buried oxide layers. For eight Channel devices, three different Channel spacings (200 GHz, 100 GHz, and 50 GHz) with cross talk levels of -32.31dB, -31.87dB, and -27.28dB and insertion loss levels of -1.43dB, -4.2dB, and -2.3dB, respectively, are demonstrated. Fourteen Channel AWGs with 170 GHz Channel spacing and 16 Channel AWGs with 87 GHz Channel spacing are shown to have a cross talk value of -21.67dB and -24.30dB and insertion loss value of -4.2dB and -3.8dB, respectively. Two AWGs with 10 nm difference in Channel peak are designed, and the measurements show a 9.3 nm difference. The transmission spectrum shift as a function of temperature is found to be 0.22 nm/°C.
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a low noise high Channel Count 20 ghz passively mode locked quantum dot laser grown on si
Optical Fiber Communication Conference, 2019Co-Authors: Songtao Liu, Daehwan Jung, Justin Norman, M J Kennedy, A C Gossard, John E BowersAbstract:We report, for the first time, a low noise high-Channel-Count 20 GHz passively mode locked quantum dot laser grown on CMOS compatible on-axis (001) silicon substrate. The laser demonstrates a wide mode locking regime in the O-band. A record low timing jitter value of 82.7 fs (4–80 MHz) and a narrow RF 3-dB linewidth of 1.8 kHz are reported. A total of 58 wavelength Channels within 3 dB optical bandwidth (80 lines within 10 dB) is also shown. The integrated average relative intensity noise values of the whole spectrum and a single Channel are − 152 dB/Hz and − 133 dB/Hz in the frequency range from 10 MHz to 10 GHz, respectively.
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high Channel Count 20 ghz passively mode locked quantum dot laser directly grown on si with 41 tbit s transmission capacity
Optica, 2019Co-Authors: Songtao Liu, Daehwan Jung, Justin Norman, M J Kennedy, A C Gossard, Hon Ki Tsang, John E BowersAbstract:Low-cost, small-footprint, highly efficient, and mass-producible on-chip wavelength-division-multiplexing (WDM) light sources are key components in future silicon electronic and photonic integrated circuits (EPICs), which can fulfill the rapidly increasing bandwidth and lower energy per bit requirements. We present here, for the first time to our knowledge, a low-noise high-Channel-Count 20 GHz passively mode-locked quantum dot laser grown on a complementary metal-oxide-semiconductor compatible on-axis (001) silicon substrate. The laser demonstrates a wide mode-locking regime in the O band. A record low timing jitter value for passively mode-locked semiconductor lasers of 82.7 fs (4–80 MHz) and a narrow RF 3 dB linewidth of 1.8 kHz are measured. The 3 dB optical bandwidth of the comb is 6.1 nm (containing 58 lines, with 80 lines within the 10 dB bandwidth). The integrated average relative intensity noise values of the whole spectrum and a single wavelength Channel are −152 dB/Hz and −133 dB/Hz in the frequency range from 10 MHz to 10 GHz, respectively. Utilizing 64 Channels, an aggregate total transmission capacity of 4.1 terabits per second is realized by employing a 32 Gbaud Nyquist four-level pulse amplitude modulation format. The demonstrated performance makes the laser a compelling on-chip WDM source for multi-terabit/s optical interconnects in future large-scale silicon EPICs.
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OFC - A Low-Noise High-Channel-Count 20 GHz Passively Mode Locked Quantum Dot Laser Grown on Si
Optical Fiber Communication Conference (OFC) 2019, 2019Co-Authors: Songtao Liu, Daehwan Jung, Justin Norman, M J Kennedy, A C Gossard, John E BowersAbstract:We report, for the first time, a low noise high-Channel-Count 20 GHz passively mode locked quantum dot laser grown on CMOS compatible on-axis (001) silicon substrate. The laser demonstrates a wide mode locking regime in the O-band. A record low timing jitter value of 82.7 fs (4–80 MHz) and a narrow RF 3-dB linewidth of 1.8 kHz are reported. A total of 58 wavelength Channels within 3 dB optical bandwidth (80 lines within 10 dB) is also shown. The integrated average relative intensity noise values of the whole spectrum and a single Channel are − 152 dB/Hz and − 133 dB/Hz in the frequency range from 10 MHz to 10 GHz, respectively.
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high Channel Count 20 ghz passively mode locked quantum dot laser directly grown on si with 4 1 tbit s transmission capacity
arXiv: Optics, 2018Co-Authors: Songtao Liu, Daehwan Jung, Justin Norman, M J Kennedy, A C Gossard, Hon Ki Tsang, John E BowersAbstract:Low cost, small footprint, highly efficient and mass producible on-chip wavelength-division-multiplexing (WDM) light sources are key components in future silicon electronic and photonic integrated circuits (EPICs) which can fulfill the rapidly increasing bandwidth and lower energy per bit requirements. We present here, for the first time, a low noise high-Channel-Count 20 GHz passively mode-locked quantum dot laser grown on complementary metal-oxide-semiconductor compatible on-axis (001) silicon substrate. The laser demonstrates a wide mode-locking regime in the O-band. A record low timing jitter value of 82.7 fs (4 - 80 MHz) and a narrow RF 3-dB linewidth of 1.8 kHz are measured. The 3 dB optical bandwidth of the comb is 6.1 nm (containing 58 lines, with 80 lines within the 10 dB bandwidth). The integrated average relative intensity noise values of the whole spectrum and a single wavelength Channel are - 152 dB/Hz and - 133 dB/Hz in the frequency range from 10 MHz to 10 GHz, respectively. Utilizing 64 Channels, an aggregate total transmission capacity of 4.1 terabits per second is realized by employing a 32 Gbaud Nyquist four-level pulse amplitude modulation format. The demonstrated performance makes the laser a compelling on-chip WDM source for multi-terabit/s optical interconnects in future large-scale silicon EPICs.