PHOTONIC CRYSTAL FIBERS FOR SUPERCONTINUUM GENERATION

PCFsenable flexible design of properties like dispersion,

nonlinearity etc.

Supercontinuum generationin PCFs enables applications like

spectroscopy, OCT, broadband sources

Result from interplay of nonlinear effects like SPM, XPM, Raman

scattering, FWM

Chalcogenide PCFsprovide high nonlinearity for spectral

broadening

Silicon nanowireshave high nonlinearity from large surface-to-

volume ratio

ProposedSi nanowire embedded PCFfor broadened spectrum

around 1550nm

Pentagonal lattice gives high birefringence

Tailored Si nanowire radius to get zero dispersion near 1550nm

Flattened, low dispersion and high nonlinearity obtained

Comparative studyof Si-nanowire, As2S3, and Silica PCFs

Si-nanowire PCF gives best characteristics for supercontinuum

generation

685nm broad spectrum from 1235-1920nm demonstrated with 25W,

50fs pulse

Key Highlights

PCFs enable flexible engineering of properties for nonlinear

applications

Chalcogenide and Si-nanowire PCFs provide high nonlinearity for

supercontinuum

Dispersion engineering by structural design enables broad spectra

Proposed Si-nanowire PCF gives ultra-flattened dispersion and high

nonlinearity

685nm wide supercontinuum spectrum achieved, suitable for optical

communications

Si-nanowire PCF outperforms alternatives like As2S3 and Silica PCFs

DISASTER MANAGEMENT SYSTEM USING FREE SPACE OPTICAL

COMMUNICATION

Introduction

India prone to natural disasters like floods, cyclones, earthquakes

etc.

Disaster management deals with protecting people and property

during disasters

FSO allows quick wireless communication by transmitting light

beams through air

Allows high bandwidth data transmission without need for license

Proposed System

Detect disasters like earthquakes, floods using sensors

Interface sensors to microcontroller to monitor readings

Trigger audio messages on crossing threshold values

Transmit audio messages to remote locations using laser

Intensity modulation of laser beam with audio signal

At receiver, convert light to electrical signal and play audio

Methodology

Use microphone for audio input, record messages in voice module

Interface sensors and voice module to microcontroller

Amplify messages and use laser driver to modulate light signal

At receiver, solar panel converts modulated light to electrical signal

Amplify recovered signal and feed it to speaker

Results

Implemented voice recording and playback circuitry

Interfaced sensors and voice module to microcontroller

Built transmitter to intensity modulate laser with audio

Constructed receiver with solar panel for opto-electrical conversion

Conclusion

Prototype demonstrates FSO based disaster alert system

Quickly establishes communication without infrastructure

Can transmit emergency data to aid disaster response

Leverages high bandwidth of FSO for critical applications

Key Highlights

FSO allows rapidly setting up wireless communication during

disasters

Sensors interfaced to microcontroller detect calamities like quakes,

floods

Recorded audio messages transmitted by modulating laser beam

Solar panel at receiver converts light signal back to electrical signal

Demonstrates using FSO for disaster alert and emergency

communication

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