In this work, the optical absorption analysis of the Vertical Photodetector for Optical Interconnect is done. For efficient detection of the signal at the receiver, a photodetector is required for designing of efficient optical interconnects. The light transmitted from the optical source is coupled into the waveguide and received by the detector. Vertical photodetector can be designed using Si and Ge but due to large bandgap, Si can’t detect the optical signal efficiently at wavelengths used for optical communication (1.3 to 1.55 μm). This can be done by using smaller band gap material (Ge) to design a photo- detector. Ge photo- detector offer high performance optical interface solutions. The Optical absorption property of photodetector is analyzed using Lumerical FDTD. It is observed that the absorption rate of vertical Ge-Si photodetector vary in different plane and provides high responsivity at 1.55 μm because the region of absorption can be made longer to enable full absorption. We investigate the absorption rate of the designed vertical photodetector because the responsivity of the photodetector depends on the absorption rate. The designed structure can be used in on-chip optical interconnect with high absorption rate and low cost.
The limitation of conventional electronics is reduced by optical integrated circuits because of its high speed information and processing. Reversible logic gates are favorable in the processing of optical signals in optical domain. In all reversible gates inputs and outputs are correlated that is advantageous to collect the information from inputs and outputs. Reversible gates are useful in high speed data transmission with low power dissipation. Reversible gates are also used in quantum computing with low loss of information. In the current work, Reversible Feynman and Fredkin optical gates are designed using Mach Zehnder Modulator for high speed information processing. A Mach Zehnder Modulator has capability to switch the source light according biased electrical signal. The amount of biased electrical signal modulates the output. The reversible optical gates are used in optical switching, optical modulator and as protection switch. The proposed gates are explained with mathematical formulation and the truth table of the reversible gates is verified using Lumerical Interconnect tool.
In this work, we present the performance analysis of the Cu(InGa)Se2 (CIGS) thin-film solar cell by exploring the physics of varying CIGS thickness, bandgap, and the device temperature. The thickness optimization of the CIGS layer is important as this lowers the large-scale manufacturing cost and eliminates the issues associated with the handling of bulky conventional solar cells. The chalcopyrite CIGS material bandgap varies from 1eV to 1.7 eV depending upon the value of ‘x’ in the formula CuIn1-xGaxSe2. The bandgap can be engineered by varying the gallium (Ga) and indium (In) composition in CuIn1-xGaxSe2. The structure is numerically simulated using the SCAPS-1D code. We investigate how the photovoltaic parameters of the solar cell such as Voc, Jsc, FF, and η are affected by varying the thickness of the absorber layer ranging from 1m to 2μm and bandgap value from 1 eV to 1.7 eV. Further, we demonstrate how the performance of this chalcopyrite material based solar cell varies with the increase in the temperature ranging from 300- 360K. By detailed understanding, we anticipate that an efficient CIGS solar cell can be developed in the future.
In recent years, as demand for high speed communication with advanced technology is increasing in optical communicat ion,so optical logic gates are being widely investigated for various applications in signal processing such as optical binary adder, optical counters, optical time division mult iplexing and low power computing etc. In the proposed work we have demonstrated the implementation of different logic gates such as AND, OR, XOR, XNOR, NAND and NOR which are the basic components to design any combinational and sequential circuits using Mach Zehnder Modulator (MZM). The MZM minimizes the effect of dispersion and provides the fast switching for high speed optical communicat ion. The MZM is used for controlling the amplitude of optical wave by applying voltage that introduced phase shift in the wave passing through the arm. This allows us to switch the output power from high to low or vice - versa (from login 1 to 0 or vice-versa). The proposed optical logic gates using MZM has low complexity and high scalability.