Zexuan Qiang - Academia.edu (original) (raw)

Papers by Zexuan Qiang

Optics Communications, Aug 1, 2003

Based on the Giles model with ASE, modeling for all-optical gain-clamped L-band EDFA using a sing... more Based on the Giles model with ASE, modeling for all-optical gain-clamped L-band EDFA using a single fiber Bragg grating (FBG) is built. The influence of the configuration, the pump wavelength, the Bragg wavelength, the reflectivity, the length of erbium doped fiber (EDF) and the pump power to the gain-clamped characteristics is studied. Finally, a set of parameters for a gain-clamped L-band EDFA with flat-gain band is given.

Proceedings of SPIE, Oct 18, 2006

In this paper, we present the simulation results on the absorption modification in photonic cryst... more In this paper, we present the simulation results on the absorption modification in photonic crystal (PC) structures. For one-dimensional (1D) PC, using transfer matrix method (TMM), we obtained enhanced absorption in both defect-free and defect based PC structures. High absorption (>60%) and small bandwidth (< 0.1 λ0) at defect level were observed with optimal absorption layers of 10-15 for structures with single defect. We also present the modified infrared absorption in two-dimensional photonic crystal slabs (2D PCS), based on the three-dimensional finite-difference time-domain method (3D FDTD). The normalized absorption power spectral density in single defect based 2D PCS structures increased by a factor of 18 at the PC defect mode level. This enhancement factor is largely dependent upon the spectral overlap between the absorption material and the defect mode cavity. Complete absorption suppression within the photonic bandgap region was also observed in defect-free cavities, and in single defect cavities when the absorption spectral band has no overlap with the photonic bandgap.

IEEE Photonics Technology Letters, Sep 1, 2006

A fast approach based on effective index perturbation method is proposed to evaluate the intrinsi... more A fast approach based on effective index perturbation method is proposed to evaluate the intrinsic characteristics of photonic-crystal-slab-based microcavity with two-dimensional finite-difference time-domain (2-D FDTD) technique. For two widely used single defect structures, less than 2% computational error was obtained in calculating the defect mode frequencies. Accurate prediction of cavity modal properties and resonant peak frequencies is feasible based on 2-D FDTD simulation by adjusting the effective index to match the dielectric band edge for donor-like defect mode. The correlation between the modified effective index and the cavity (lasing) mode with the highest quality factor offers an efficient tool in the design of defect mode based photonic crystal microcavities. Index Terms-Cavity quality factor, defect-mode cavity, effective index method (EIM), effective index perturbation (EIP), photonic crystal slabs (PCSs).

Optics Express, Feb 19, 2007

We present here an optical add-drop filter (ADF) design based on ultra-compact photonic crystal r... more We present here an optical add-drop filter (ADF) design based on ultra-compact photonic crystal ring resonators (PCRRs). The normalized transmission spectra for single-ring and dual-ring configurations have been investigated by using the two-dimensional finite-difference time-domain (FDTD) technique in a square lattice dielectric-rod photonic-crystal structure. With the introduction of four scatterers at the corners of quasisquare-ring PCRR, high wavelength selectivity and close to 100% drop efficiency can be obtained. Both backward-and forward-dropping were achieved by controlling the coupling efficiency between two PCRR rings for resonant modes with different symmetry. The resonant-mode quality factor Q and the wavelength tunability were also analyzed, opening opportunities for PCRRs as ultra-compact filters, optical add-drop multiplexers, electrooptical N x N switches and electrooptical modulators.

Asia Communications and Photonics Conference and Exhibition, 2009

Abstract A Low-loss Fabry-Perot interferometer (FPI) constructed in a two-dimensional photonic cr... more Abstract A Low-loss Fabry-Perot interferometer (FPI) constructed in a two-dimensional photonic crystal (2D PhC) is proposed and investigated. The 2D PhC consists of a square-lattice of cylindrical silicon rods in air. It has flat equal frequency contours (EFCs) in the ...

Journal of Nanophotonics, Jun 1, 2007

Significantly enhanced absorption at the defect mode can be obtained at surfacenormal direction i... more Significantly enhanced absorption at the defect mode can be obtained at surfacenormal direction in a dielectric single-defect photonic-crystal-slab, with an absorption enhancement factor greater than 4,000. Complete absorption suppression within the photonic bandgap region can also be observed in defect-free photonic crystal cavities. High spectral selectivity and tunability is feasible with defect mode engineering, making photonic crystal defect cavities a promising nanophotonic platform for the spectrally selective infrared sensing and hyper-spectral imaging, with the incorporation of quantum well or quantum dot infrared photodetector heterostructures.

Optoelectronics Letters, May 1, 2010

A new photonic crystal ring resonator (PCRR) configuration is provided based on two-dimensional (... more A new photonic crystal ring resonator (PCRR) configuration is provided based on two-dimensional (2D) square lattice photonic crystal (PC) silicon rods. The ring is formed by removing the line defect along M direction instead of conventional X direction. Its spectral information including transmission intensity, dropped efficiency and quality factor affected by different physical parameters and the cascaded engineering including parallel and serial configurations are numerically analyzed with 2D finite-difference time-domain (FDTD) technique. The spectral quality factor of more than 830 and dropped efficiency of 90% at 1550 nm channel can be obtained with a less than 2.2 m ring radius.

Journal of Nanophotonics, May 1, 2008

Ultra-compact polymer modulators were proposed and simulated, based on the hybrid integration of ... more Ultra-compact polymer modulators were proposed and simulated, based on the hybrid integration of functional polymer materials with Si based photonic-crystal ring resonators (PCRRs). The simulations were carried out on device characteristics with an effective ring radius of 2.3 µm and tunable polymer index from 1.785 to 1.805. Investigating the loss, the cavity quality factor Q, and the free spectral range of such PCRRs, we found a 0.02 dB intrinsic loss that is independent of diameter, unlike the loss that varies inversely with diameter in microstrip resonators. Close to 100% drop efficiency at the drop channel of 1557.5 nm was obtained by design with a high spectral selectivity of Q greater than 1319 in the single-ring PCRR-based add-drop filters with ring radius of 1.2 µm.

Optics Communications, Jun 1, 2004

The insertion loss and channel crosstalk of an etched diffraction grating (EDG) demultiplexer is ... more The insertion loss and channel crosstalk of an etched diffraction grating (EDG) demultiplexer is significantly influenced by phase and amplitude errors. A statistical model to estimate the impact of phase and amplitude errors in an EDG is developed using scalar diffraction theory. The numerical results show that the influence of amplitude errors caused by nonuniformity in deposition and etching process is not distinct until the resolution of photomask is better than 40 nm. A basic requirement for an EDG demultiplexer with crosstalk less than)30 dB is given.

A fast approach based on effective index perturbation method is proposed to evaluate the intrinsi... more A fast approach based on effective index perturbation method is proposed to evaluate the intrinsic characteristics of photonic-crystal-slab-based microcavity with two-dimensional finite-difference time-domain (2-D FDTD) technique. For two widely used single defect structures, less than 2% computational error was obtained in calculating the defect mode frequencies. Accurate prediction of cavity modal properties and resonant peak frequencies is feasible based on 2-D FDTD simulation by adjusting the effective index to match the dielectric band edge for donor-like defect mode. The correlation between the modified effective index and the cavity (lasing) mode with the highest quality factor offers an efficient tool in the design of defect mode based photonic crystal microcavities. Index Terms-Cavity quality factor, defect-mode cavity, effective index method (EIM), effective index perturbation (EIP), photonic crystal slabs (PCSs).

Microwave and Optical Technology Letters, Oct 10, 2019

We presented a compact and enduring multiwavelength Tm-doped fiber laser at 2 μm employing a micr... more We presented a compact and enduring multiwavelength Tm-doped fiber laser at 2 μm employing a microfiber knot resonator (MKR). The MKR, made by the flame-brushing technique, has a fiber diameter of 10 μm and a ring diameter of 150 μm. The MKR plays a role as both the comb filter and the power equalization device, which is critical for the stable multiwavelength Tm-doped fiber laser. By properly adjusting the pump power, three wavelength lasing channels (1956.2, 1964.4, and 1971.8 nm) were observed stable and their average power density was around −8.76 dBm with 1 W pump power. In addition, the channel spacing is 5.8 nm with the 3-dB bandwidth of the channel smaller than 0.5 nm. The experiments demonstrated that the MKR can be utilized as a comb filter with the suitable transmission spectrum to reach a steady multiwavelength Tm-doped fiber laser.

Conference proceedings, Oct 1, 2007

Optics Express, 2007

We report here far infrared photonic crystals comprised of a lattice-matched pair of semiconducto... more We report here far infrared photonic crystals comprised of a lattice-matched pair of semiconductor materials: GaP and Si, or GaAs and Ge, or AlAs and GaAs. The crystals operate in a wavelength range where the real refractive index of one material undergoes a major dispersion associated with the LO and TO phonon absorption peaks. Using electromagnetic theory, we investigated the photonic-bandgap response for both TE and TM polarizations. Propagation losses for two types of crystals are estimated in this paper. These structures offer promise for the integration of III-V materials (GaP, GaAs) on group IV (Si, or Ge) for practical, active, far infrared photonic devices, such as light sources, amplifiers, modulators, reconfigurable waveguides and switches.

Chinese Physics Letters, Dec 1, 2012

We report 1 × 4 optical splitters (OSs) with different splitting ratios based on either rod-type ... more We report 1 × 4 optical splitters (OSs) with different splitting ratios based on either rod-type or hole-type silicon photonic crystal self-collimation ring resonators (SCRRs). The four beam splitters of the OSs are formed by changing the radii of silicon rods or air holes. The light beam propagating along the SCRR can be controlled by the self-collimation effect. The transmission spectra at the through and drop ports are investigated by using the finite-difference time-domain (FDTD) method. The simulated results agree well with the theoretical calculation. For 1550-nm dropping wavelength, the free spectral ranges for rod-type and hole-type configurations are 28.8nm and 32.5nm, respectively, which almost cover the whole optical communication C-band window. The dimensions of these structures are only about 10 μm × 10 μm.

2018 Asia Communications and Photonics Conference (ACP), 2018

Upconversion luminescence at ~800 nm based on Thulium-doped NaYF4 nanoparticles excited by a 980 ... more Upconversion luminescence at ~800 nm based on Thulium-doped NaYF4 nanoparticles excited by a 980 nm laser has been experimentally demonstrated. Under different concentrations, the fluorescence power is proportional to the pump power.

Optics Express, May 4, 2009

We report angular and polarization dependent transmission properties of Fano resonance optical fi... more We report angular and polarization dependent transmission properties of Fano resonance optical filters with transferred silicon nanomembrane on glass substrate. The transmission spectra of the filters can have either weak or strong polarization and angular dependence, depending on properties of individual Fano resonance modal dispersion. Measurement results agree very well with simulations based on a rigorous coupled-wave analysis for the transmission spectra, on planewave expansion wave-vector technique for the dispersion property analysis, and on a three-dimensional finite-difference time-domain technique for the propagating modal study. These results will provide importance guidance for the design of a new class of ultra-compact surface-normal frequency selective components with preferred polarization and angular properties. These components are highly desirable for silicon photonic integration.

Appl. Opt., Apr 21, 2009

New all-optical NOT and NOR logic gates based on a single ultracompact photonic crystal ring reso... more New all-optical NOT and NOR logic gates based on a single ultracompact photonic crystal ring resonator (PCRR) have been proposed. The PCRR was formed by removing the line defect along the ΓM direction instead of the conventional ΓX direction in a square-pattern cylindrical silicon-rod photonic crystal structure. The behavior of the proposed logic gates is qualitatively analyzed with the theory of beam interference and then numerically investigated by use of the two-dimensional finite-difference time-domain method. No nonlinear material is required with less than a 2:2 μm effective ring radius. The wavelengths of the input signal and the probe signal are the same. This new device can potentially be used in on-chip photonic logic-integrated circuits.

2006 International Symposium on Biophotonics, Nanophotonics and Metamaterials, 2006

A modified single defect photonic-crystal-slab microcavity is proposed by adjusting the six inner... more A modified single defect photonic-crystal-slab microcavity is proposed by adjusting the six inner holes size and shifting two of them along the ΓK direction. Two-dimensional finite-difference time-domain (FDTD) and modified effective index method have been introduced to investigate and optimize the characteristics of monopole mode of photonic crystal microcavities. It shows that by broking the symmetry of the microcavity, the quality factor can be greatly increased.

2018 Asia Communications and Photonics Conference (ACP), 2018

We propose a compact high-power, ~1ns, MHz pulsed ytterbium laser for micromachining using gain-s... more We propose a compact high-power, ~1ns, MHz pulsed ytterbium laser for micromachining using gain-switching and master oscillator power amplifier (MOPA) technique . We preliminary obtained a 1.2-ns, 1-MHz, 49-mW average single-mode output power before MOPA.

LEOS 2007 - IEEE Lasers and Electro-Optics Society Annual Meeting Conference Proceedings, 2007

There is an increasing and largely unfulfilled need for nanometer-scale photonic components, both... more There is an increasing and largely unfulfilled need for nanometer-scale photonic components, both passive and active, in intra-chip optical communications and other high-speed, ultra-low- power photonic applications. Silicon-based components are favored because they are capable of on-chip-network integration with CMOS electronics. This paper presents a detailed analysis of radiative waveguide bend loss in single-ring PCRRs, as well as bend loss in micro-strip rings as a function of effective radius from 1 to 15 mum at lambda ~ 1550 nm.

Optics Communications, Aug 1, 2003

Based on the Giles model with ASE, modeling for all-optical gain-clamped L-band EDFA using a sing... more Based on the Giles model with ASE, modeling for all-optical gain-clamped L-band EDFA using a single fiber Bragg grating (FBG) is built. The influence of the configuration, the pump wavelength, the Bragg wavelength, the reflectivity, the length of erbium doped fiber (EDF) and the pump power to the gain-clamped characteristics is studied. Finally, a set of parameters for a gain-clamped L-band EDFA with flat-gain band is given.

Proceedings of SPIE, Oct 18, 2006

In this paper, we present the simulation results on the absorption modification in photonic cryst... more In this paper, we present the simulation results on the absorption modification in photonic crystal (PC) structures. For one-dimensional (1D) PC, using transfer matrix method (TMM), we obtained enhanced absorption in both defect-free and defect based PC structures. High absorption (>60%) and small bandwidth (< 0.1 λ0) at defect level were observed with optimal absorption layers of 10-15 for structures with single defect. We also present the modified infrared absorption in two-dimensional photonic crystal slabs (2D PCS), based on the three-dimensional finite-difference time-domain method (3D FDTD). The normalized absorption power spectral density in single defect based 2D PCS structures increased by a factor of 18 at the PC defect mode level. This enhancement factor is largely dependent upon the spectral overlap between the absorption material and the defect mode cavity. Complete absorption suppression within the photonic bandgap region was also observed in defect-free cavities, and in single defect cavities when the absorption spectral band has no overlap with the photonic bandgap.

IEEE Photonics Technology Letters, Sep 1, 2006

A fast approach based on effective index perturbation method is proposed to evaluate the intrinsi... more A fast approach based on effective index perturbation method is proposed to evaluate the intrinsic characteristics of photonic-crystal-slab-based microcavity with two-dimensional finite-difference time-domain (2-D FDTD) technique. For two widely used single defect structures, less than 2% computational error was obtained in calculating the defect mode frequencies. Accurate prediction of cavity modal properties and resonant peak frequencies is feasible based on 2-D FDTD simulation by adjusting the effective index to match the dielectric band edge for donor-like defect mode. The correlation between the modified effective index and the cavity (lasing) mode with the highest quality factor offers an efficient tool in the design of defect mode based photonic crystal microcavities. Index Terms-Cavity quality factor, defect-mode cavity, effective index method (EIM), effective index perturbation (EIP), photonic crystal slabs (PCSs).

Optics Express, Feb 19, 2007

We present here an optical add-drop filter (ADF) design based on ultra-compact photonic crystal r... more We present here an optical add-drop filter (ADF) design based on ultra-compact photonic crystal ring resonators (PCRRs). The normalized transmission spectra for single-ring and dual-ring configurations have been investigated by using the two-dimensional finite-difference time-domain (FDTD) technique in a square lattice dielectric-rod photonic-crystal structure. With the introduction of four scatterers at the corners of quasisquare-ring PCRR, high wavelength selectivity and close to 100% drop efficiency can be obtained. Both backward-and forward-dropping were achieved by controlling the coupling efficiency between two PCRR rings for resonant modes with different symmetry. The resonant-mode quality factor Q and the wavelength tunability were also analyzed, opening opportunities for PCRRs as ultra-compact filters, optical add-drop multiplexers, electrooptical N x N switches and electrooptical modulators.

Asia Communications and Photonics Conference and Exhibition, 2009

Abstract A Low-loss Fabry-Perot interferometer (FPI) constructed in a two-dimensional photonic cr... more Abstract A Low-loss Fabry-Perot interferometer (FPI) constructed in a two-dimensional photonic crystal (2D PhC) is proposed and investigated. The 2D PhC consists of a square-lattice of cylindrical silicon rods in air. It has flat equal frequency contours (EFCs) in the ...

Journal of Nanophotonics, Jun 1, 2007

Significantly enhanced absorption at the defect mode can be obtained at surfacenormal direction i... more Significantly enhanced absorption at the defect mode can be obtained at surfacenormal direction in a dielectric single-defect photonic-crystal-slab, with an absorption enhancement factor greater than 4,000. Complete absorption suppression within the photonic bandgap region can also be observed in defect-free photonic crystal cavities. High spectral selectivity and tunability is feasible with defect mode engineering, making photonic crystal defect cavities a promising nanophotonic platform for the spectrally selective infrared sensing and hyper-spectral imaging, with the incorporation of quantum well or quantum dot infrared photodetector heterostructures.

Optoelectronics Letters, May 1, 2010

A new photonic crystal ring resonator (PCRR) configuration is provided based on two-dimensional (... more A new photonic crystal ring resonator (PCRR) configuration is provided based on two-dimensional (2D) square lattice photonic crystal (PC) silicon rods. The ring is formed by removing the line defect along M direction instead of conventional X direction. Its spectral information including transmission intensity, dropped efficiency and quality factor affected by different physical parameters and the cascaded engineering including parallel and serial configurations are numerically analyzed with 2D finite-difference time-domain (FDTD) technique. The spectral quality factor of more than 830 and dropped efficiency of 90% at 1550 nm channel can be obtained with a less than 2.2 m ring radius.

Journal of Nanophotonics, May 1, 2008

Ultra-compact polymer modulators were proposed and simulated, based on the hybrid integration of ... more Ultra-compact polymer modulators were proposed and simulated, based on the hybrid integration of functional polymer materials with Si based photonic-crystal ring resonators (PCRRs). The simulations were carried out on device characteristics with an effective ring radius of 2.3 µm and tunable polymer index from 1.785 to 1.805. Investigating the loss, the cavity quality factor Q, and the free spectral range of such PCRRs, we found a 0.02 dB intrinsic loss that is independent of diameter, unlike the loss that varies inversely with diameter in microstrip resonators. Close to 100% drop efficiency at the drop channel of 1557.5 nm was obtained by design with a high spectral selectivity of Q greater than 1319 in the single-ring PCRR-based add-drop filters with ring radius of 1.2 µm.

Optics Communications, Jun 1, 2004

The insertion loss and channel crosstalk of an etched diffraction grating (EDG) demultiplexer is ... more The insertion loss and channel crosstalk of an etched diffraction grating (EDG) demultiplexer is significantly influenced by phase and amplitude errors. A statistical model to estimate the impact of phase and amplitude errors in an EDG is developed using scalar diffraction theory. The numerical results show that the influence of amplitude errors caused by nonuniformity in deposition and etching process is not distinct until the resolution of photomask is better than 40 nm. A basic requirement for an EDG demultiplexer with crosstalk less than)30 dB is given.

A fast approach based on effective index perturbation method is proposed to evaluate the intrinsi... more A fast approach based on effective index perturbation method is proposed to evaluate the intrinsic characteristics of photonic-crystal-slab-based microcavity with two-dimensional finite-difference time-domain (2-D FDTD) technique. For two widely used single defect structures, less than 2% computational error was obtained in calculating the defect mode frequencies. Accurate prediction of cavity modal properties and resonant peak frequencies is feasible based on 2-D FDTD simulation by adjusting the effective index to match the dielectric band edge for donor-like defect mode. The correlation between the modified effective index and the cavity (lasing) mode with the highest quality factor offers an efficient tool in the design of defect mode based photonic crystal microcavities. Index Terms-Cavity quality factor, defect-mode cavity, effective index method (EIM), effective index perturbation (EIP), photonic crystal slabs (PCSs).

Microwave and Optical Technology Letters, Oct 10, 2019

We presented a compact and enduring multiwavelength Tm-doped fiber laser at 2 μm employing a micr... more We presented a compact and enduring multiwavelength Tm-doped fiber laser at 2 μm employing a microfiber knot resonator (MKR). The MKR, made by the flame-brushing technique, has a fiber diameter of 10 μm and a ring diameter of 150 μm. The MKR plays a role as both the comb filter and the power equalization device, which is critical for the stable multiwavelength Tm-doped fiber laser. By properly adjusting the pump power, three wavelength lasing channels (1956.2, 1964.4, and 1971.8 nm) were observed stable and their average power density was around −8.76 dBm with 1 W pump power. In addition, the channel spacing is 5.8 nm with the 3-dB bandwidth of the channel smaller than 0.5 nm. The experiments demonstrated that the MKR can be utilized as a comb filter with the suitable transmission spectrum to reach a steady multiwavelength Tm-doped fiber laser.

Conference proceedings, Oct 1, 2007

Optics Express, 2007

We report here far infrared photonic crystals comprised of a lattice-matched pair of semiconducto... more We report here far infrared photonic crystals comprised of a lattice-matched pair of semiconductor materials: GaP and Si, or GaAs and Ge, or AlAs and GaAs. The crystals operate in a wavelength range where the real refractive index of one material undergoes a major dispersion associated with the LO and TO phonon absorption peaks. Using electromagnetic theory, we investigated the photonic-bandgap response for both TE and TM polarizations. Propagation losses for two types of crystals are estimated in this paper. These structures offer promise for the integration of III-V materials (GaP, GaAs) on group IV (Si, or Ge) for practical, active, far infrared photonic devices, such as light sources, amplifiers, modulators, reconfigurable waveguides and switches.

Chinese Physics Letters, Dec 1, 2012

We report 1 × 4 optical splitters (OSs) with different splitting ratios based on either rod-type ... more We report 1 × 4 optical splitters (OSs) with different splitting ratios based on either rod-type or hole-type silicon photonic crystal self-collimation ring resonators (SCRRs). The four beam splitters of the OSs are formed by changing the radii of silicon rods or air holes. The light beam propagating along the SCRR can be controlled by the self-collimation effect. The transmission spectra at the through and drop ports are investigated by using the finite-difference time-domain (FDTD) method. The simulated results agree well with the theoretical calculation. For 1550-nm dropping wavelength, the free spectral ranges for rod-type and hole-type configurations are 28.8nm and 32.5nm, respectively, which almost cover the whole optical communication C-band window. The dimensions of these structures are only about 10 μm × 10 μm.

2018 Asia Communications and Photonics Conference (ACP), 2018

Upconversion luminescence at ~800 nm based on Thulium-doped NaYF4 nanoparticles excited by a 980 ... more Upconversion luminescence at ~800 nm based on Thulium-doped NaYF4 nanoparticles excited by a 980 nm laser has been experimentally demonstrated. Under different concentrations, the fluorescence power is proportional to the pump power.

Optics Express, May 4, 2009

We report angular and polarization dependent transmission properties of Fano resonance optical fi... more We report angular and polarization dependent transmission properties of Fano resonance optical filters with transferred silicon nanomembrane on glass substrate. The transmission spectra of the filters can have either weak or strong polarization and angular dependence, depending on properties of individual Fano resonance modal dispersion. Measurement results agree very well with simulations based on a rigorous coupled-wave analysis for the transmission spectra, on planewave expansion wave-vector technique for the dispersion property analysis, and on a three-dimensional finite-difference time-domain technique for the propagating modal study. These results will provide importance guidance for the design of a new class of ultra-compact surface-normal frequency selective components with preferred polarization and angular properties. These components are highly desirable for silicon photonic integration.

Appl. Opt., Apr 21, 2009

New all-optical NOT and NOR logic gates based on a single ultracompact photonic crystal ring reso... more New all-optical NOT and NOR logic gates based on a single ultracompact photonic crystal ring resonator (PCRR) have been proposed. The PCRR was formed by removing the line defect along the ΓM direction instead of the conventional ΓX direction in a square-pattern cylindrical silicon-rod photonic crystal structure. The behavior of the proposed logic gates is qualitatively analyzed with the theory of beam interference and then numerically investigated by use of the two-dimensional finite-difference time-domain method. No nonlinear material is required with less than a 2:2 μm effective ring radius. The wavelengths of the input signal and the probe signal are the same. This new device can potentially be used in on-chip photonic logic-integrated circuits.

2006 International Symposium on Biophotonics, Nanophotonics and Metamaterials, 2006

A modified single defect photonic-crystal-slab microcavity is proposed by adjusting the six inner... more A modified single defect photonic-crystal-slab microcavity is proposed by adjusting the six inner holes size and shifting two of them along the ΓK direction. Two-dimensional finite-difference time-domain (FDTD) and modified effective index method have been introduced to investigate and optimize the characteristics of monopole mode of photonic crystal microcavities. It shows that by broking the symmetry of the microcavity, the quality factor can be greatly increased.

2018 Asia Communications and Photonics Conference (ACP), 2018

We propose a compact high-power, ~1ns, MHz pulsed ytterbium laser for micromachining using gain-s... more We propose a compact high-power, ~1ns, MHz pulsed ytterbium laser for micromachining using gain-switching and master oscillator power amplifier (MOPA) technique . We preliminary obtained a 1.2-ns, 1-MHz, 49-mW average single-mode output power before MOPA.

LEOS 2007 - IEEE Lasers and Electro-Optics Society Annual Meeting Conference Proceedings, 2007

There is an increasing and largely unfulfilled need for nanometer-scale photonic components, both... more There is an increasing and largely unfulfilled need for nanometer-scale photonic components, both passive and active, in intra-chip optical communications and other high-speed, ultra-low- power photonic applications. Silicon-based components are favored because they are capable of on-chip-network integration with CMOS electronics. This paper presents a detailed analysis of radiative waveguide bend loss in single-ring PCRRs, as well as bend loss in micro-strip rings as a function of effective radius from 1 to 15 mum at lambda ~ 1550 nm.