Semiconductor Quantum-Dot Based Wideband Emitter for Optical Sensors

Djie, H. S.; Dimas, Clara; Ooi, Boon S.

doi:10.1109/icsens.2005.1597853

Cited by 4 publications

(1 citation statement)

References 13 publications

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“…Titled angle SLDs often results in high coupling loss in fiber pigtailing during packaging. Recently, we reported the fabrication of QD SLDs that incorporate a photon absorber (PA) section in the device cavity to restrain the Fabry-Perot resonance, hence suppress lasing action and reduce optical feedback that result in spectral ripple [15].…”

Section: Introductionmentioning

confidence: 99%

InGaAs/GaAs Quantum-Dot Superluminescent Diode for Optical Sensor and Imaging

et al. 2007

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We report on the design and fabrication of a novel wideband superluminescent diode (SLD) based on InGaAs/GaAs quantum-dot structure. In this device, we monolithically integrate a photon absorber section to suppress lasing action and optical feedback oscillation. The fabricated SLDs produce a close-to-Gaussian shaped spectrum centered at 1210 nm with a bandwidth of 135 nm. Spectral ripple as low as 0.3 dB has been measured.Index Terms-Broadband light source, optical coherence tomography (OCT), quantum dot (QD), superluminescent diode.

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Section: Introductionmentioning

confidence: 99%

InGaAs/GaAs Quantum-Dot Superluminescent Diode for Optical Sensor and Imaging

et al. 2007

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1.3-$\mu$m Quantum-Dot Multisection Superluminescent Diodes With Extremely Broad Bandwidth

Yang

Martinez

Saiz

et al. 2007

IEEE Photon. Technol. Lett.

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proper operation of the proposed UWB circuit. Experimental results show that the pulse generator can yield an output pulse of 235 ps duration which has a bandwidth of 4.3 GHz at the center frequency of 2.15 GHz. The circuit is easy to implement and have low profile. It can be used for mobile UWB applications where space requirements are stringent. ACKNOWLEDGMENTSThe authors thank Ayhan Bozkurt during implementation of the circuit and Sertac Yilmaz for the time measurements of the UWB pulse generator. APPENDIX: TRANSMISSION LINE LENGTH RELATION AND THE TIME DELAYTo obtain the desired monopulse with no zero-frequency component, pulse width, or equivalently time delay between even and odd mode pulses, and the transmission line length should be both taken into consideration as design parameters. Basically, the odd mode and even mode propagate at different velocities, and the difference in velocities will create the time difference between the even and odd mode pulses at a specific point on the transmission line. So, for the desired pulse, the transmission line length should be a design parameter as well as the time duration of the pulse. To obtain a monopulse, the difference between time delays (t 2 Ϫ t 1 ) should be equal to the pulse width ⌬t. This statement can be expressed as,Assume that the length of the transmission line is l, then, the time duration that it takes for the odd and even mode voltages to reach the output port [port 3 in Fig. 3(a)] will be given by,where e ϭ c/ ͱ eff,e and o ϭ c/ ͱ eff,o are the velocities of the even and odd modes. Using Eqs. (A1)-(A3), we can obtain the transmission line length versus desired time delay between even and odd pulses relation as, l ϭ ⌬t ϫ c 1 ͱ eff,e Ϫ ͱ eff,oAs an example, for the same FR4 substrate of r ϭ 4.6, the calculated values of effective dielectric constants for the odd and even modes are given in Eq. (17), and if the desired time delay is taken as 75 ps, then, the transmission line length is calculated as 9.3 cm using Eq. (A4). Note that for a higher dielectric constant material and using meander trace, the area of the transmission line circuit could be made a few square-cm. Actually, antenna performances with respect to phase variation of the far-field, transfer function, and transient response in time-domain also pose a serious impact on antenna application. In this article, a printed SWB antenna is proposed and studied. It is composed by a corner-rounded ground plane, a tapered microstrip feeder and a patch made by a half-disc and a half-ellipse. Then various antenna characteristics are experimentally analyzed in detail by building a transceiving antenna system, including VSWR, radiation patterns, gain, group delay, and antenna transfer function. In addition, transient response is carefully investigated and presented by using four different signals, which provides designers with much useful information on true application of the antenna behind its more than 25:1 impedance bandwidth. DESCRIPTION OF THE ANTENNAConfiguration of the proposed SWB antenna is ...

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