AbstractIn this paper, an all-optical filter is proposed which employs a resonant cavity localized between input and output waveguides as wavelength selecting part of the filter. We study the impact of different parameters on the filtering of the structure using plane wave expansion and finite difference time domain methods. We also study the effect of the output waveguide position on the performance of the filter and results show that the proper position of the output waveguide is straight to the center of the resonant cavity. The initial form of filter is capable of selecting the optical waves at λ = 1,554.2 nm and the transmission efficiency of the filter is obtained about 100 %. The total footprint of the filter is Manuscript profile

در این مقاله، یک سوئیچ نوری گرافنی پلاسمونیک با ویژگیهای بهینه تر و تعداد چهار کانال طراحی و شبیه سازی گردیده است. هر یک از این کانالها دارای عرض یکسانی به اندازه 20 نانومتر هستند که در فاصله 30 نانومتری از هم قرار گرفته اند. عمل سوئیچینگ با اعمال ولتاژ به بخشی از کانالهای خروجی قابل کنترل و تنظیم می باشد و می توان توسط ولتاژ کانال خروجی را تعیین نمود. از ویژگیهای عملکرد این سوئیچ نوری دستیابی به میزان گذردهی نسبتا بالا با میزان تلفات بسیار کم در محدوده فرکانسی 30 تراهرتز می باشد. همچنین در این ساختار میزان همشنوایی به صورت محسوسی بسیار کم می باشد. این ساختار در پتانسیلهای شیمیایی متفاوتی بررسی شده که یکی از بهترین حالات آن در پتانسیل شیمیایی 0.4 اتفاق افتاده است. ساختار ساده و کنترل پذیری آسان از مزایای این ساختار می باشد. تمامی تجزیه و تحلیلها و همچنین شبیه سازیهای مربوطه در نرم افزارهای Lumerical و MATLAB انجام پذیرفته اند. Manuscript profile

This article presents an avalanche photodiode with quantum dot layers in its active region which operates at 10µm. Performance of this structure is based on intersubband impact ionization phenomenon in quantum dots. It requires lower energy threshold for the onset of avalanche phenomenon, hence it can work in lower operating voltages than bulks. In this paper, by presenting a theoretical approach for  intersubband transition rate and electron-electron interaction the photo-generated current was modeled and consequently the responsivity can be calculated.  Results show that peak responsivity at a voltage of 14V is obtained about 1.9 A/W. Also the dark current is modeled and calculated at different temperatures and applied voltages. Manuscript profile

Transition metal dichalcogenide (TMDC) materials are very important in
electronic and optical integrated circuits and their growth is of great importance in this
field. In this paper we present growth and fabrication of MoS2 (Molibdan DiSulfide)
thin films by chemical bath method (CBD). The CBD method of growth makes it
possible to simply grow large area scale of the thin layers of this material in lower
temperatures (near room temperature) and atmosphere pressure in comparison to costly
complicated growth methods. The results show the effect of growth temperature and
time on the quality of layers and XRD measurements were performed for analysis of
crystalline structure of layers. The results show that for the bath temperature of 60oC
and for 75 min growth time, better quality of layers can be obtained with low intensity.
The low intensity of XRD peaks belongs to poor crystalline structure of layers. For
higher bath temperatures, the films lose their uniformity. The results were confirmed by
SEM images. Manuscript profile

An experimental study over the optical response of thin MoS2 films grown
by chemical bath deposition (CBD) method is presented. As two important factors, the
effect of bath temperature and growth time are considered on the photocurrent
generation in the grown samples. The results show that increasing the growth time leads
to better optical response and higher difference between dark and photocurrent. For
higher bath temperatures the layer loses its uniformity and the current reduces. Better
performance of optical response is obtained for t=90min and T=70oC. We also studied
the effect of post-annealing on the performance and quality of thin films. The I-V
measurements show no current flow for annealed films because of rupture of the film
structure. Temporal response of the films to light source ON and OFF states is also
studied and the results showed relaxation of photocurrent after about several seconds.
The importance of the MoS2 thin films obtained by CBD method is low-temperature
process and large area of fabricated layers which can be used in many applications. Manuscript profile