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| 52. |
- Lim, J.J., et al.
(author)
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Static and dynamic performance optimization of a 1.3 µm GaInNAs ridge waveguide laser
- 2008
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In: 2008 International Conference on Numerical Simulation of Optoelectronic Devices, NUSOD'08; Nottingham; United Kingdom; 1 September 2008 through 4 September 2008. - 9781424423071 ; , s. 121-122
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Conference paper (peer-reviewed)abstract
- In this work, we optimise the structure of an uncooled directly modulated 1.3 μm GaInNAs ridge waveguide laser for high temperature operation. The static and dynamic performance of the optimised design is analyzed using an accurate in-house 2D electro-opto-thermal laser simulator. The optimised structure Is shown to have a lower threshold current, higher efficiency, higher modulation bandwidth and lower vertical beam divergence compared to a reference structure with a conventional design. Large-signal 10 Gbit/s digital modulation simulations were performed and demonstrate the improved performance of the optimised structure especially under high temperature operation.
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| 53. |
- Lim, Jun, et al.
(author)
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Static and dynamic performance optimisation of a 1.3 mu m GaInNAs ridge waveguide laser
- 2008
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In: Optical and Quantum Electronics. - : Springer Science and Business Media LLC. - 0306-8919 .- 1572-817X. ; 40:14-15, s. 1181-1186
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Journal article (peer-reviewed)abstract
- In this work, we perform a multi-parameter design study to improve the performance of an uncooled directly modulated 1.3 mu m GaInNAs ridge waveguide laser for high speed operation especially at high temperature. The static and dynamic performance of the improved design is analyzed using an accurate in-house 2D electro-opto-thermal laser simulator. The improved structure is shown to have a lower threshold current, higher thermal roll-over limit and higher modulation bandwidth-especially under high temperature operation. The improved structure also has a lower vertical beam divergence compared to a reference structure with a conventional design.
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| 54. |
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| 55. |
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| 56. |
- Liu, Fangfei, et al.
(author)
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Compact optical temporal differentiator based on silicon microring resonator
- 2008
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In: Optics Express. - 1094-4087. ; 16:20, s. 15880-15886
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Journal article (peer-reviewed)abstract
- We propose and experimentally demonstrate a temporal differentiator in optical field based on a silicon microring resonator with a radius of 40 mu m. The microring resonator operates near the critical coupling region, and can take the first order derivative of the optical field. It features compact size thus is suitable for integration with silicon-on-insulator (SOI) based optical and electronic devices. The performance of this optical differentiator is tested using signals with typical shapes such as Gaussian, sinusoidal and square-like pulses at data rates of 10 Gb/s and 5 Gb/s.
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| 57. |
- Liu, F., et al.
(author)
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Demonstration of wavelength multicasting using a silicon mode-split microring resonator
- 2009
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In: 2009 15th Asia-Pacific Conference on Communications, APCC 2009. - 9781424447855 ; , s. 626-629
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Conference paper (peer-reviewed)abstract
- We experimentally demonstrate wavelength multicasting based on free carrier dispersion effect in a silicon mode-split microring resonator with a radius of ∼10 μm. The mode-split of the resonator is caused by mutual coupling between the co-propagating and counter-propagating modes inside the microring resonator, which is induced by the periodic grating-like roughness of the sidewalls. The free carriers are generated through the two photon absorption (TPA) effect and blue shift the resonance spectrum. 1.25-Gb/s data carried by the pump is simultaneously converted to two probe channels placed in the split resonances separated by ∼0.326 nm.
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| 58. |
- Liu, F., et al.
(author)
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On-chip photonic generation of ultra-wideband monocycle pulses
- 2009
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In: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 45:24, s. 1247-1248
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Journal article (peer-reviewed)abstract
- Proposed and experimentally demonstrated is photonic generation of ultra-wideband (UWB) monocycle pulses using a silicon microring resonator to perform phase-modulation-to-intensity-modulation conversion. The microring resonator features compact size and thus is cost-effective especially for applications in UWB communication systems that support multiple users. As a microring resonator with a pin diode can function as a modulator, the use of the microring resonator to realise bi-phase modulation is discussed.
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| 59. |
- Liu, Jin-ming, et al.
(author)
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Mid-term effects of lung volume reduction surgery on pulmonary function in patients with chronic obstructive pulmonary disease
- 2007
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In: Chinese Medical Journal. - 0366-6999. ; 120:8, s. 658-662
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Journal article (peer-reviewed)abstract
- Background Now lung volume reduction surgery (LVRS) has become one of the most effective methods for the management of some cases of severe chronic obstructive pulmonary disease (COPD). We evaluated the mid-term effects of LVRS on pulmonary function in patients with severe COPD. Methods Ten male patients with severe COPD aged 38-70 years underwent LVRS and their pulmonary function was assessed before, 3 months and 3 years after surgery. The spirometric and gas exchange parameters included residual volume, total lung capacity, inspiratory capacity, forced vital capacity, forced expiratory volume in one second, diffusion capacity for CO, and arterial blood gas. A 6-minute walk distance (6MWD) test was performed. Results As to preoperative assessment, most spirometric parameters and 6MWD were significantly improved after 3 months and slightly 3 years after LVRS. Gas exchange parameters were significantly improved 3 months after surgery, but returned to the preoperative levels after 3 years. Conclusions LVRS may significantly improve pulmonary function in patients with severe COPD indicating for LVRS. Mid-term pulmonary function 3 years after surgery can be decreased to the level at 3 months after surgery. Three years after LVRS, lung volume and pulmonary ventilation function can be significantly improved, but the improvement in gas exchange function was not significant.
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