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127 results on '"Childs, David T. D."'

1. Resonator embedded photonic crystal surface emitting lasers

Author

Bian, Zijun, Zhao, Xingyu, Liu, Jingzhao, Kim, Daehyun, McKenzie, Adam F., Thoms, Stephen, Reynolds, Paul, Gerrard, Neil D., Kyaw, Aye S. M., Grant, James, Rae, Katherine, Orchard, Jonathan R., Hill, Calum H., Munro, Connor W., Ivanov, Pavlo, Childs, David T. D., Taylor, Richard J. E., and Hogg, Richard A.

Published
2024
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2. Void Engineering in Epitaxially Regrown GaAs-Based Photonic Crystal Surface Emitting Lasers by Grating Profile Design

Author

McKenzie, Adam F., King, Ben C., Rae, Katherine J., Thoms, Stephen, Gerrard, Neil D., Orchard, Jonathan, Nishi, Kenishi, Takemasa, Keizo, Sugawara, Mitsuru, Taylor, Richard J. E., Childs, David T. D., McLaren, Donald A., and Hogg, Richard A.

Subjects
Physics - Applied Physics, Condensed Matter - Materials Science, Physics - Optics
Abstract

We report the engineering of air-voids embedded in GaAs-based photonic crystal surface emitting lasers realised by metalorganic vapour-phase epitaxy regrowth. Two distinct void geometries are obtained by modifying the photonic crystal grating profile within the reactor prior to regrowth. The mechanism of void formation is inferred from scanning transmission electron microscopy analysis, with the evolution of the growth front illustrated though the use of an AlAs/GaAs superlattice structure. Competition between rapid lateral growth of the (100) surface and slow diffusion across higher index planes is exploited in order to increase void volume, leading to an order of magnitude reduction in threshold current and an increase in output power through an increase in the associated grating coupling strength., Comment: 7 pages, 4 figures

Published
2020
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3. Coherent Power Scaling in Photonic Crystal Surface Emitting Laser Arrays

Author

King, Ben C., Rae, Katherine J., McKenzie, Adam F., Boldin, Aleksander, Kim, Daehyun, Gerrard, Neil D., Li, Guangrui, Nishi, Kenishi, Sugawara, Mitsuru, Taylor, Richard J. E., Childs, David T. D., and Hogg, Richard A.

Subjects
Physics - Optics, Physics - Applied Physics
Abstract

A key benefit of photonic crystal surface emitting lasers (PCSELs) is the abillity to increase output power through scaling the emission area while mainting high quality single mode emission, allowing them to close the brightness gap which exists between semiconductor lasers and gas and fibre lasers. However, there are practical limits to the size, and hence power, of an individual PCSEL device and there are trade-offs between single-mode stability and parasitic in-plane losses with increasing device size. In this paper we discuss 2D coherent arrays as an approach to area and coherent power scaling of PCSELs. We demonstrate in two and three element PCSEL arrays an increase in the differential efficiency of the system due to a reduction in in-plane loss., Comment: Paper submitted. 9 pages, 4 figures

Published
2020
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5. Epitaxially regrown quantum dot photonic crystal surface emitting lasers

Author

Kyaw, Aye S. M., primary, King, Ben C., additional, McKenzie, Adam F., additional, Bian, Zijun, additional, Kim, Daehyun, additional, Gerrard, Neil D., additional, Nishi, Kenichi, additional, Takemasa, Keizo, additional, Sugawara, Mitsuru, additional, Childs, David T. D., additional, Hill, Calum H., additional, Taylor, Richard J. E., additional, and Hogg, Richard A., additional

Published
2024
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6. Epitaxially regrown quantum dot photonic crystal surface emitting lasers

Author

Kyaw, Aye S. M., King, Ben C., McKenzie, Adam F., Bian, Zijun, Kim, Daehyun, Gerrard, Neil D., Nishi, Kenichi, Takemasa, Keizo, Sugawara, Mitsuru, Childs, David T. D., Hill, Calum H., Taylor, Richard J. E., Hogg, Richard A., Kyaw, Aye S. M., King, Ben C., McKenzie, Adam F., Bian, Zijun, Kim, Daehyun, Gerrard, Neil D., Nishi, Kenichi, Takemasa, Keizo, Sugawara, Mitsuru, Childs, David T. D., Hill, Calum H., Taylor, Richard J. E., and Hogg, Richard A.

Abstract

Quantum dot-based epitaxially regrown photonic crystal surface emitting lasers are demonstrated at room temperature. The GaAs-based devices, which are monolithically integrated on the same wafer, exhibit ground state lasing at ∼1230 nm and excited state lasing at ∼1140 nm with threshold current densities of 0.69 and 1.05 kA/cm2, respectively.

Published
2024

8. Epitaxially Regrown Quantum Dot Photonic Crystal Surface Emitting Laser

Author

Kyaw, Aye S. M., primary, King, Ben C., additional, McKenzie, Adam F., additional, Gerrard, Neil D., additional, Bian, Zijun, additional, Kim, Daehyun, additional, Liu, Jingzhao, additional, Zhao, Xingyu, additional, Nishi, Kenichi, additional, Takemasa, Keizo, additional, Sugawara, Mitsuru, additional, Childs, David T. D., additional, Hill, Calum H., additional, Taylor, Richard J. E., additional, and Hogg, Richard A., additional

Published
2022
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10. Resonator Embedded Photonic Crystal Surface Emitting Lasers

Author

Bian, Zijun, primary, Zhao, Xingyu, additional, Rae, Katherine J., additional, Kyaw, Aye S. M., additional, Kim, Daehyun, additional, McKenzie, Adam F., additional, King, Ben C., additional, Liu, Jingzhao, additional, Thoms, Stephen, additional, Reynolds, Paul, additional, Gerrard, Neil D., additional, Grant, James, additional, Orchard, Jonathan R., additional, Hill, Calum H., additional, Munro, Connor W., additional, Ivanov, Pavlo, additional, Childs, David T. D., additional, Taylor, Richard J. E., additional, and Hogg, Richard A., additional

Published
2022
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12. Monolithic All-Semiconductor PCSELs emitting at 1.3µm

Author

Hill, Calum, primary, Orchard, Jonathan R., additional, Javed, Ibrahim, additional, Munro, Connor W., additional, Kim, Daehyun, additional, Bian, Zijun, additional, McKenzie, Adam F., additional, Gerrard, Neil D., additional, Rae, Katherine J., additional, Ivanov, Pavlo, additional, Taylor, Richard J. E., additional, Hogg, Richard A., additional, and Childs, David T. D., additional

Published
2021
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14. Systematic Study of External Optical Feedback Tolerance in 1300 nm Quantum Dot Lasers

Author

Sobhani, Soroush A., Hogg, Richard A., Takemasa, Keizo, Nishi, Kenichi, Sugawara, Mitsuru, and Childs, David T. D.

Abstract

Resilience of 1300nm In(Ga)As/GaAs quantum dot lasers to external optical feedback is systematically investigated from − 10°C to 85 °C. The high-resolution spectral and current-dependent linewidth enhancement factor is measured for all modes in the positive net modal gain region. Complimentary to that, analysis of the free-running and under deployment specific feedback relative intensity noise is discussed in the context of compliance against the IEEE 802.3ah specifications at the full range of temperatures.

Published
2023
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16. Coherent power scaling in photonic crystal surface emitting laser arrays

Author

King, Ben C., primary, Rae, Katherine J., additional, McKenzie, Adam F., additional, Boldin, Aleksandr, additional, Kim, Daehyun, additional, Gerrard, Neil D., additional, Li, Guangrui, additional, Nishi, Kenichi, additional, Takemasa, Keizo, additional, Sugawara, Mitsuru, additional, Taylor, Richard J. E., additional, Childs, David T. D., additional, and Hogg, Richard A., additional

Published
2021
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18. Properties of laterally coupled photonic crystal surface-emitting laser two-dimensional arrays (Conference Presentation)

Author

Boldin, Aleksandr, primary, Kim, Daehyun, additional, Taylor, Richard J. E., additional, King, Ben, additional, McKenzie, Adam, additional, Babazadeh, Nasser, additional, Ivanov, Pavlo, additional, Orchard, Jonathan R., additional, Gerrard, Neil D., additional, Childs, David T. D., additional, and Hogg, Richard A., additional

Published
2020
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20. Superluminescent diode with a broadband gain based on self-assembled InAs quantum dots and segmented contacts for an optical coherence tomography light source.

Author

Nobuhiko Ozaki, Childs, David T. D., Sarma, Jayanta, Roberts, Timothy S., Takuma Yasuda, Hiroshi Shibata, Hirotaka Ohsato, Eiichiro Watanabe, Naoki Ikeda, Yoshimasa Sugimoto, and Hogg, Richard A.

Subjects
*SUPERLUMINESCENT diodes, *LIGHT emitting diodes, *QUANTUM dots, *COHERENCE (Optics), *BANDWIDTHS, *ELECTROLUMINESCENCE, *CURRENT density (Electromagnetism)
Abstract

We report a broadband-gain superluminescent diode (SLD) based on self-assembled InAs quantum dots (QDs) for application in a high-resolution optical coherence tomography (OCT) light source. Four InAs QD layers, with sequentially shifted emission wavelengths achieved by varying the thickness of the In0.2Ga0.8As strain-reducing capping layers, were embedded in a conventional p-n heterojunction comprising GaAs and AlGaAs layers. A ridge-type waveguide with segmented contacts was formed on the grown wafer, and an as-cleaved 4-mm-long chip (QD-SLD) was prepared. The segmented contacts were effective in applying a high injection current density to the QDs and obtaining emission from excited states of the QDs, resulting in an extension of the bandwidth of the electroluminescence spectrum. In addition, gain spectra deduced with the segmented contacts indicated a broadband smooth positive gain region spanning 160 nm. Furthermore, OCT imaging with the fabricated QD-SLD was performed, and OCT images with an axial resolution of ∼4 μm in air were obtained. These results demonstrate the effectiveness of the QD-SLD with segmented contacts as a highresolution OCT light source. [ABSTRACT FROM AUTHOR]

Published
2016
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22. Development of a broadband superluminescent diode based on self-assembled InAs quantum dots and demonstration of high-axial-resolution optical coherence tomography imaging

Author

Ozaki, Nobuhiko, primary, Yamauchi, Sho, additional, Hayashi, Yuma, additional, Watanabe, Eiichiro, additional, Ohsato, Hirotaka, additional, Ikeda, Naoki, additional, Sugimoto, Yoshimasa, additional, Furuki, Kenji, additional, Oikawa, Yoichi, additional, Miyaji, Kunio, additional, Childs, David T D, additional, and Hogg, Richard A, additional

Published
2019
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24. Tunable external cavity laser diode based on wavelength controlled self-assembled InAs quantum dots for swept-source optical coherence tomography applications at 1100 nm wavelength band

Author

Ozaki, Nobuhiko, primary, Childs, David T. D., primary, Boldin, Aleksandr, primary, Ikuno, Daigo, primary, Onoue, Katsuya, primary, Ohsato, Hirotaka, primary, Watanabe, Eiichiro, primary, Ikeda, Naoki, primary, Sugimoto, Yoshimasa, primary, and Hogg, Richard A., primary

Published
2019
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25. Development of All-Semiconductor Photonic Crystal Surface Emitting Lasers

Author

Taylor, Richard J E, primary, Childs, David T D, additional, Li, Guangrui, additional, Sarma, Jayanta, additional, Bian, Zijun, additional, King, Ben C, additional, Boldin, Aleksandr, additional, Ignatova, Olesya, additional, Thoms, Stephen, additional, Stevens, Ben J, additional, Roberts, Timothy S, additional, Harrison, Brett, additional, Orchard, Jon, additional, Gerrard, Neil D, additional, Ivanov, Pavlo, additional, McKenzie, Adam, additional, and Hogg, Richard A, additional

Published
2019
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26. Develoment of All-Semiconductor Photonic Crystal Surface Emitting Lasers

Author

Taylor, Richard J E, primary, Li, Guangrui, additional, King, Ben, additional, Bian, Zijun, additional, Boldin, Aleksandr, additional, Stevens, Benjamin, additional, Roberts, Tim, additional, Tooley, Ian, additional, Thoms, Steven, additional, Sarma, Jayanta, additional, Childs, David T D, additional, and Hogg, Richard A, additional

Published
2018
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35. Proposal for Common Active 1.3- $\mu$ m Quantum Dot Electroabsorption Modulated DFB Laser.

Author

Sobhani, Soroush A., Stevens, Ben J., Babazadeh, Nasser, Takemasa, Keizo, Nishi, Kenichi, Sugawara, Mitsuru, Hogg, Richard A., and Childs, David T. D.

Abstract

Opportunities for the monolithic integration of a novel common quantum dot (QD)-active electroabsorption modulated laser are explored. An electric-field and temperature-dependent spectroscopic study of optical absorption and gain are presented in the state-of-the-art 1.3- $\mu \text{m}$ In(Ga)As/GaAs QD active material. The unique gain/absorption spectral shape, attributed to the QD’s density of states, allows for a number of possible modulation schemes dependent upon the selected laser wavelength detuning from the gain peak. Intensity modulation and change in absorption, leading to negative chirp operation, are demonstrated via absorption spectroscopy and gain measurement of eight-layer-stack QD-active material. Such a device would be able to provide positive or negative chirp dependent upon modulation scheme and gain/Bragg wavelength detuning. [ABSTRACT FROM AUTHOR]

Published
2019
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41. Superluminescent diode with a broadband gain based on self-assembled InAs quantum dots and segmented contacts for an optical coherence tomography light source

Author

Ozaki, Nobuhiko, primary, Childs, David T. D., additional, Sarma, Jayanta, additional, Roberts, Timothy S., additional, Yasuda, Takuma, additional, Shibata, Hiroshi, additional, Ohsato, Hirotaka, additional, Watanabe, Eiichiro, additional, Ikeda, Naoki, additional, Sugimoto, Yoshimasa, additional, and Hogg, Richard A., additional

Published
2016
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44. Coherently Coupled Photonic-Crystal Surface-Emitting Laser Array

Author

Taylor, Richard J. E., primary, Childs, David T. D., additional, Ivanov, Pavlo, additional, Stevens, Ben J., additional, Babazadeh, Nasser, additional, Sarma, Jayanta, additional, Khamas, Salam, additional, Crombie, Alex J., additional, Li, Guangrui, additional, Ternent, Gary, additional, Thoms, Stephen, additional, Zhou, Haiping, additional, and Hogg, Richard A., additional

Published
2015
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48. Strain Balancing of Metal-Organic Vapour Phase Epitaxy InAs/GaAs Quantum Dot Lasers.

Author

Roberts, Timothy S., Stevens, Benjamin J., Clarke, Edmund, Tooley, Ian, Orchard, Jonathan, Farrer, Ian, Childs, David T. D., Babazadeh, Nasser, Ozaki, Nobuhiko, Mowbray, David, and Hogg, Richard A.

Abstract

Incorporation of a GaAs0.8P0.2 layer allows strain balancing to be achieved in self-assembled InAs/GaAs quantum dots (QDs) grown by metal organic vapor phase epitaxy. Tuneable wavelength and high density are obtained through growth parameter optimization, with emission at 1.27 μm and QD layer density 3 × 10 10 cm–2. Strain balancing allows close vertical stacking (30 nm) of the QD layers, giving the potential for increased optical gain. Modeling and device characterization indicates minimal degradation in the optical and electrical characteristics unless the phosphorus percentage is increased above 20%. Laser structures are fabricated with a layer separation of 30 nm, demonstrating low temperature lasing with a threshold current density of 100 A/cm2 at 130 K without any facet coating. [ABSTRACT FROM PUBLISHER]

Published
2017
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