Studies on Effects of Optical Feedback Based Micro-Ring Resonator on the Integrated 40 GHz Opto-Electronic Oscillator

  • Ugra Mohan Roy

Student thesis: Doctoral ThesisDoctor of Philosophy

Abstract

This thesis presents the design and simulation of 40 GHz Integrated Opto-Electronic Oscillator (IOEO) with high spectral purity, minimum phase noise, high quality factor as well a better thermal and frequency stability. Simulation studies of the designed IOEO have been carried out using a novel Linear Time Invariant (LTI) architecture having all optical components in the feedback path which is contrary to the conventional OEO. The long optical fiber present in the conventional OEO has been replaced by an Integrated Optical Microring Resonator (IOMR). The proposed IOMR replaces the few km long fiber cable making the IOEO compact. The designed IOEO exhibits a minimum phase noise of -245 dBcHz−1 at 100 kHz offset compared to phase noise of -160 dBcHz−1 of conventional design. The computation of the phase noise of the designed IOEO has been carried out using variance method. The proposed design of IOEO also eliminates the fiber loss thereby improving the Quality (Q) factor of the IOEO. The simulation study on the effect of IOMR on the Q factor of the IOEO reveals the loaded quality factor of 1000. Through simulation studies invoking Sellmeier model, the thermal stability of the designed IOEO is found to be ±0.325 ppmK−1 over a temperature range of 150-300K.Frequency stability analysis of the designed IOEO has been studied analytically using two port network theory. Effect of Butt-coupling coefficient on the stability is also explored.

This thesis presents a novel analytical model for the straight and curved waveguides of IOMR, invoking the Coupled Mode Theory (CMT). The potential utility of derived mathematical expressions has been illustrated in the calculation of quality factor, coupling length and gap between straight and curved waveguides of the ring resonator. The significance of Butt-coupling coefficient in the CMT has been explored and its effects on resonance and output power of IOMR have been analyzed for a novel resonance condition. The analysis of the effects of gap between straight and curved waveguides on the output power of IOEO facilitates additional insight into the underlying principles and its phase noise. The phase noise contribution of IOMR in the IOEO is found to be extremely small and is insignificant. The fabrication tolerance of the designed IOMR has been computed using derived analytical model to support the feasibility of manufacturing the IOEO.

The simulation model of proposed IOEO has been utilized for design and simulation of an optical beam steering system. The simulation study directed towards Wavelength Division Multiplexing (WDM) substantiates the utility and relevance of IOEO as modulator and modulation frequency generator simultaneously. This thesis also presents design and simulation studies on an IOEO based novel architecture for label-free optical Bio-sensor. The proposed IOEO based label free sensor eliminates the laborious labeling procedure and its associated cumbersome effects. The proposed Bio-sensor exhibits a bulk refractive index sensitivity of -140 MHzRIU−1.
Date of Award2016
Original languageEnglish
Awarding Institution
  • Coventry University
  • M S Ramaiah University of Applied Sciences
SupervisorGovind Kadambi (Supervisor) & Omid Razmkhah (Supervisor)

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