BSc Thesis

INVESTIGATION ON MAPPING HIGHLY SENSITIVE AND TUNABLE HOLLOW CORE PHOTONIC CRYSTAL FIBER FACILITATED WITH ULTRA-SHORT PULSE FOR MULTIPURPOSE APPLICATIONS

Classical photonic crystal fiber (PCF) designs often faced a trade-off: high sensitivity with high confinement losses, or low sensitivity with minimal losses. My undergraduate thesis introduced a new sensing paradigm by combining hollow-core PCF (HC-PCF) with ultra-short pulses (USP) to detect petrochemical adulteration with enhanced precision and computational efficiency.

The major contributions of my thesis are as follows:

• Novel Sensing Approach – Developed a USP–HC-PCF–based detection method for diesel adulteration, analyzing pulse shape alterations (compression sensitivity, power upsurge) as a simpler yet highly effective alternative to traditional computationally heavy sensitivity parameters.

• Design & Simulation – Proposed and simulated an elliptical hollow-core PCF model using COMSOL Multiphysics, ensuring strong light confinement (94–98% power fraction) and maintaining single-mode operation around the telecom wavelength of 1550 nm.

• Nonlinearity Analysis – Extracted key nonlinear parameters (dispersion, propagation constant derivatives, nonlinear gamma) showing unique signatures for each adulterated sample, enabling accurate classification without exhaustive multiparameter monitoring.

• Performance Metrics – Demonstrated compression sensitivity up to 16% and power surges exceeding 600 W, validating the viability of USP–HC-PCF for real-world petrochemical sensing.

• Fabrication Compatibility & Scalability – Evaluated silica-based designs compatible with conventional fabrication methods and highlighted future applications in biomedical sensing, disease diagnostics, and nano-level chip integration.

In short, my undergraduate thesis provided a computationally efficient, highly sensitive, and fabrication-friendly optical sensing framework, advancing the intersection of ultrafast optics and photonic crystal fiber design.

Poster of Thesis