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 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.
The fast growing market of organic electronics, including organic photovoltaics (OPV), stimulates the development of
versatile technologies for structuring thin-film materials. Ultraviolet lasers have proven their full potential for patterning
single organic layers, but in a multilayer organic device the obtained layer selectivity is limited as all organic layers show
high UV absorption. In this paper, we introduce mid-infrared (IR) resonant ablation as an alternative approach, in which
a short pulse mid-infrared laser can be wavelength tuned to one of the molecular vibrational transitions of the organic
material to be ablated. As a result, the technique is selective in respect of processing a diversity of organics, which
usually have different infrared absorption bands. Mid-IR resonant ablation is demonstrated for a variety of organic thin
films, employing both nanosecond (15 ns) and picosecond (250 ps) laser pulses tunable between 3 and 4 microns. The
nanosecond experimental set-up is based on a commercial laser at 1064 nm pumping a singly resonant Optical
Parametric Oscillator (OPO) built around a Periodically-Poled Lithium Niobate (PPLN) crystal with several Quasi-Phase
Matching (QPM) periods, delivering more than 0.3 W of mid-IR power, corresponding to 15 μJ pulses. The picosecond
laser set-up is based on Optical Parametric Amplification (OPA) in a similar crystal, allowing for a comparison between
both pulse length regimes.
The wavelength of the mid-infrared laser can be tuned to one of the molecular vibrational transitions of the organic
material to be ablated. For that reason, the IR absorption spectra of the organic materials used in a typical OPV device
were characterized in the wavelength region that can be reached by the laser setups. Focus was on OPV substrate
materials, transparent conductive materials, hole transport materials, and absorber materials. The process has been
successfully demonstrated for selective thin film patterning, and the influence of the various laser parameters is
This paper presents a study of selective ablation of thin organic films (LEP- Light Emitting Polymer, PEDOT:PSS- Poly
3,4-ethylenedioxythiophene: polystyrene sulfonate) by using 248 nm Excimer laser, on various kinds of multilayered
SiN barrier foils for the development of Organic Light Emitting Diodes (OLED). Different Silicon Nitride (SiN) barrier
foils with dedicated absorption spectra are taken into account for this purpose. The drive for looking into different types
of SiN originates from the fact that the laser selective removal of a polymer without damage to the barrier layer
underneath is challenging in the dynamic laser processing of thin films. The barrier is solely responsible for the proper
encapsulation of the OLED stack. The main limitation of current OLED design is its shorter life span, which is directly
related to the moisture or water permeation into the stack, leading to black spots. An optimization of laser parameters
like fluence and number of shots has been carried out for the various types of SiN barrier foils. We are able to obtain a
wider working process window for the selective removal of LEP and PEDOT:PSS from SiN barrier, by variation of the
different types of SiN.