Browsing by Author "Donegan, John"
Now showing items 1-20 of 68
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1.3 μm wavelength tunable single-mode laser arrays based on slots
Donegan, John (2021)Two twelve-channel arrays based on surface-etched slot gratings, one with non-uniformly spaced slots and another with uniformly spaced slots are presented for laser operation in the O-band. A wavelength tuning range greater ... -
850 nm GaAs/AlGaAs DFB lasers with shallow surface gratings and oxide aperture
Donegan, John (2019)We present and experimentally demonstrate a novel oxide-confined ridge-waveguide distributed feedback (DFB) laser with the first-order surface grating using only a single growth step. The metal contacts are laterally offset ... -
All-optical pulse processing for advanced photonic communication system
Donegan, John; Bradley, Louise (IEEE, 2008)This paper investigates the use of a Two-Photon Absorption photodetector for high speed processing of ultrashort optical pulses in advanced photonic communication systems. Specifically the paper describes how the Two-Photon ... -
All-optical sampling based on two-photon absorption in a semiconductor microcavity for high-speed OTDM
Donegan, John; Bradley, Louise (SPIE, 2005)Future high-speed optical communications networks operating at data rates in excess of 100Gbit/s per channel will require a sensitive and ultrafast technique for precise optical signal monitoring.1 The standard way ... -
Associative Enhancement of Time Correlated Response to Heterogeneous Stimuli in a Neuromorphic Nanowire Device
Boland, John; Donegan, John (2016)In spite of the strong interest in brain‐like or neuromorphic computation, relatively few devices have emerged whose neuromorphic behavior is embedded in the hardware itself and not reliant on external programming of ... -
Athermal operation of multi-section slotted tunable lasers
Donegan, John; Bello, Frank; Mc Closkey, David (2017) -
Athermal tuning for a two-section, all-active DBR laser with high-order grating
Bello, Frank; Donegan, John; Wallace, Michael J.; McKenna, Robert; Jain, Gaurav; Lu, Qiaoyin Y.; Guo, Weihua H. (2018)We incorporate thermal effects for injection currents ranging up to 150 mA in order to model the tuning behavior of a two-section, all-active distributed-Bragg-reflector (DBR),ridge-wave guide semiconductor laser utilized ... -
Chromatic dispersion monitoring for high-speed WDM systems using two-photon absorption in a semiconductor microcavity
Donegan, John; Bradley, Louise (2009)This paper presents a theoretical and experimental investigation into the use of a two-photon absorption (TPA) photodetector for use in chromatic dispersion (CD) monitoring in high-speed, WDM network. In order to overcome ... -
Chromatic dispersion monitoring of 80 Gbps OTDM data signal via two-photon absorption in a semiconductor microcavity
Donegan, John; Bradley, Louise (2007)In this letter, a novel method of chromatic dispersion monitoring via two-photon absorption (TPA) is investigated. A specially designed semiconductor microcavity is employed as a TPA detector for monitoring ... -
CMOS-compatible multi-band plasmonic TE-pass polarizer
Bello, Frank; Donegan, John; Abadía, Nicolás; Saber, MD Ghulam; Samani, Alireza; El-Fiky, Eslam; Wang, Yun; Plant, David (2018)A CMOS-compatible plasmonic TE-pass polarizer capable of working in the O, E, S, C, L, and U bands is numerically analyzed. The device is based on an integrated hybrid plasmonic waveguide (HPW) with a segmented metal design. ... -
Collisional Broadening of Semiconductor Microcavity Polaritons
Donegan, John; Bradley, Louise; Hegarty, John (2002)We measure the effect of intensity on the homogeneous linewidth of two high finesse semiconductor microcavities in the strong coupling regime using degenerate four‐wave mixing. We find that the collisional broadening due ... -
Combining ϵ-Near-Zero Behavior and Stopped Light Energy Bands for Ultra-Low Reflection and Reduced Dispersion of Slow Light
Donegan, John; Bello, Frank; Hess, Ortwin (2017)We investigate media which exhibits epsilon-near-zero (ENZ) behavior while simultaneously sustaining stopped light energy bands which contain multiple points of zero group velocity (ZGV). This allows the merging of ... -
Confined optical modes in small photonic molecules with semiconductor nanocrystals
Donegan, John; Bradley, Louise (2004)We report on the coherent coupling of whispering gallery modes (WGMs) in a photonic molecule formed from two melamine-formaldehyde spherical microcavities coated with a thin shell of light-emitting CdTe nanocrystals ... -
Conical diffraction intensity profiles generated using a top-hat input beam
Donegan, John; Lunney, James; Eastham, Paul; Mc Closkey, David (2014) -
Constructive and destructive interference of Kerker-type scattering in an ultrathin silicon Huygens metasurface
Bradley, Louise; Donegan, John (2020)High refractive index dielectric nanoparticles have provided a new platform for exotic light manipulation through the interference of multipole modes. The Kerker effect is one example of a Huygens source design. Rather ... -
Coupled cavity modes in photonic molecules with semiconductor nanocrystals
Donegan, John; Bradley, Louise (2005)We present a detailed study of the localized coupled-cavity modes in a photonic molecule formed from two dielectric spherical microcavities with CdTe nanocrystals, which show a multi-peak narrowband modal structure resulting ... -
Description of polarisation dependence of two-photon absorption in silicon avalanche photodiodes
Donegan, John; Bradley, Louise (2010)A simple formula is obtained that very accurately describes the level of two-photon absorption (TPA) generated by elliptically polarised light in silicon avalanche photodiodes (Si-APDs). The dichroism parameter necessary ... -
Design of microcavity semiconductor devices for highly efficient optical switching and sampling applications
Bradley, Louise; Donegan, John (2002)Summary form only given. Two Photon Absorption (TPA) in semiconductors has recently been shown to be a serious candidate for optical autocorrelation of short pulses, and all-optical switching and sampling of high speed ... -
Directly accessing octave-spanning dissipative Kerr soliton frequency combs in an AlN microresonator
Donegan, John (2021)Self-referenced dissipative Kerr solitons (DKSs) based on optical microresonators offer prominent characteristics allowing for various applications from precision measurement to astronomical spectrometer calibration. To ... -
Dispersion monitoring for high-speed WDM networks via two-photon absorption in a semiconductor microcavity
Donegan, John; Bradley, Louise (2006)Due to the continued demand for bandwidth, network operators have to increase the data rates at which individual wavelengths operate at. As these data rates will exceed 100 Gbit/s in the next 5-10 years, it will be crucial ...