OPTICAL AUTOCORRELATION (Report)

 

The project aims to understand Optical Autocorrelation including building the setup from different optical components and to measure the laser linewidth in optical spectrum analyser (OSA) based on the optical beat signal of two laser paths where one is frequency-shifted by acousto-optic modulator and other propagated in a long optical fiber. Measurement is taken for two fibers of length 150m and 10km.

 

 

Direct Laser Writing and Scanning Electron Microscopy (Report) 

 

Optical pro cesses are limited by diffraction which can analytically b e expressed by the Rayleigh criteria. The aim of this exp eriment was to intro duce us with a cutting edge technique for 3D laser writing b eyond the diffraction limit, which nowadays allows an increasing numb er of applications. Obtaining knowledge of physical principles b ehind the metho d, the direct laser writing setup, attaining exp ertise on using scanning electron microscop e and imp ortant parameters to characterize the recorded samples were the key training areas of this exp eriment.

 

 

Organic Light Emitting Diodes (Report)

 

OLEDs were manufactured in the clean room by using the technique of spin coating for the deposition of the polymer layers. And it was learnt how sensible the cathode layer is for the final performance of the device. We have understood the advantages of organic sources in comparison with other ones and the important photometric parameters to characterize such sources.

 

 

Solar Cells (Report)

 

In this experiment we have examined sample solar cells in order to get insight into different characteristics of solar cells. From the experimental data solar cells were characterized after the measurements. Effect of temperature and intensity are examined.

 

 

 

An electronic machine built using combinatorial and sequential logic circuitry. It has provision for counting votes cast to three candidates, as well as the total number of votes. 

 

Special Feature: Ensuring single vote per voter. This is essential for avoiding rigging. The circuitry ensures this in the following way— When a voter casts a vote by pressing a voting switch, the input section is automatically deactivated. It can be activated only after pressing another switch, which is controlled by the presiding officer. The entire circuitry was designed using simple logic gates and no microcontroller was used. 

 

Major Challenge: First, designing the logic circuitry for ensuring one vote per voter. Second, overcoming the switch bouncing problem. The logic circuitry serving the previous purpose helps to overcome this problem too, as only the first vote is counted and then the system goes into a deactivated mode. Hence, bouncing cannot cause multiple vote cast.

 

A 4 bit computer is designed in Proteus that can execute 16 instructions. The design is inspired from the SAP-1 and SAP-2 architecture, and is generalized enough to execute more instructions.

 

 

 

Yaw control system of a wind turbine is implemented using stepper motor. A microcontroller ATmega16 is used to control the stepper motor. LDR is used to detect the angular position of the yaw. 

 

Special Feature: Whenever the yaw rotates to follow the direction of the wind, the LDRs track the change in angular position and the microcontroller accordingly commands the stepper motor to rotate the axis of the turbine to align with the wind direction. 

 

Major Challenge: First, designing the mechanical structure of the system. Second, interfacing the stepper motor.

 

 

 

As a part of undergraduate thesis work, two dimensional GaN based power semiconductor devices have been simulated to extract characteristic curves using MATLAB and TCAD softwares.