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Optical MIDO : Multiple Inputs-Digital Output : device

Alaiz-Gudin Antonio M., González-Marcos Ana P.

Opto-Electronics Review

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2021

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Vol. 29, No. 4

106--116

EN

Advances in photonic technologies, with new processes and scopes of photonic integrated circuits, have generated a lot of interest as the field allows to obtain sensors with reduced size and cost and build systems with high interconnectivity and information density. In this work, answering the needs of photonic sensors that must be portable, more energy- efficient, and more accurate than their electrical counterparts, also with a view to the emerging field of neuromorphic photonics, a versatile device is presented. The proposed device makes use of the well-known advantages provided by optical bistability. By combining two distributed feedback-multi quantum well semiconductor laser structures, this new optical multiple inputs - digital output device offers various essential purposes (such as logic gates, wavelength detector and monitoring) with no need for specific manufacturing for each of them. Through a commercial computer-aided design tool, VPIphotonics™, the necessary characterization of proposed device is also described.

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Design and analytical calculations of the width and arrangement of quantum well and barrier layers in GaN/AlGaN LED to enhance the performance

Sharma L., Sharma R.

Opto-Electronics Review

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2021

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Vol. 29, No. 4

141--147

EN

This research paper discusses an analytical approach to designing the active region of light emitting diodes to enhance its performance. The layers in the active region were modified and the effects of changing the width of quantum well and barrier layers in a multi-quantum light emitting diode on the output power and efficiency have been investigated. Also, the ratio of the quantum well width to the B layer width was calculated and proposed in this research paper. The study is carried out on two different LED structures. In the first case (i.e., first structure), the width of the quantum well layers is kept constant while the width of the B layers is varied. In the second case (i.e., second structure), both the quantum well and B layer widths are varied. Based on the simulation results, it has been observed that the LED power efficiency increases considerably for a given quantum well to B layers width ratio without increasing the production complexity. It is also seen that for a desired power efficiency the width of quantum well should be between 0.003 μm and 0.006 μm, and the range of B width (height) should be 2.2 to 6 times the quantum well width. The proposed study is carried out on the GaN-AlGaN-based multi-quantum well LED structure, but this study can be extended to multiple combinations of the semiconductor structures.

3

Temperature dependence of the spontaneous emission mechanisms of localized-state heterosystem

Lee J. C.

Optica Applicata

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2011

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Vol. 41, nr 4

911--919

EN

The temperature dependent photoluminescence (PL) spectra measured from localized-state material system is presented. Two localized-state heterosystems, including InGaN/GaN multi-quantum well (MQW) and InAs/GaAs quantum dot (QD) samples were prepared. The samples were investigated both experimentally and theoretically. It has been found that the temperature dependence of the PL peak energies from both samples behaves differently. S-shaped and anti-S-shaped PL peak energies have been observed for MQW and QD samples, respectively. We present a model which takes into account all of the key factors for the localized-carrier dynamics. The model is applied to interpret the experimental data obtained from the two kinds of material systems. Detailed discussion concerning this model provides an explicit interpretation that it is the difference in the electronic structure of the two material systems that leads to the significantly different temperature dependence of their luminescence bands.

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Recent developments and applications of quantum well infrared photodetector focal plane arrays

Gunapala S. D., Bandara S. V., Liu J. K., Luong E. M., Rafol S. B., Mumolo J. M., Ting D. Z., Bock J. J., Ressler M. E., Werner M. W., Levan P. D., Chehayeb R., Kukkonen C. A., Levy M., Levan P., Fauci M. A.

Opto-Electronics Review

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2001

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Vol. 9, No. 2

150-163

EN

One of the simplest device realisations of the calssic particle-in-the-box problem of basic quantum mechanics is the quantum well infrared photodetector (QWIP). In this paper we discuss the effect of focal plane array non-uniformity on the performance, optimisation of the detector design, material growth and processing that has culminated in realisation of large format long-wavelength QWIP cameras, holding forth great promise for many applications in 6-18 micron wavelength range in science, medicine, defence and industry. In addition, we present the recent developments in long-wavelength/very long-wavelength dualband QWIP imaging camera for various applications.