APPLICATIONS OF OPTICAL FREQUENCY COMBS IN MICROWAVE PHOTONICS AND QUANTUM OPTICS
Remarkable miniaturization of optical frequency combs was achieved using integrated microring resonators based on the Kerr nonlinearity. Operated below the parametric instability threshold, such microrings can generate high-dimensionally entangled biphoton frequency combs. To process such states, we encode qudits in the time and frequency degree of freedom of a single photon and experimentally demonstrate a deterministic high-dimensional 16 by 16 SUM gate. We then operate this gate on two frequency-bin entangled photons - each carrying two 32-dimensional qudits - to generate a two-photon four-party Greenberger-Horne-Zeilinger state. Subsequently, we utilize single-photon encoding concepts to demonstrate the first qutrit-based phase implementation of the quantum phase estimation algorithm - a key subroutine of several important algorithms - and successfully retrieve the eigenphase with one ternary digit of precision. Lastly, by manipulating the input state using an electro-optic phase modulator, we implement a tunable frequency-domain quantum walk demonstrating ballistic energy transport and energy bound states. These demonstrations highlight the potential of frequency-domain encoding and processing using well-established tools developed for the communication industry. The second part of this thesis focuses on the microwave photonic applications of frequency combs. Using dual electro-optic combs, we exploit the Vernier effect to develop an optical-based radio-frequency subsampled link and derive a detailed analytical model identifying a third-order limited operational point. In a second demonstration, we use Kerr combs to mitigate detrimental stimulated Brillouin scattering effects in long-haul analog optical links. Using both dark pulses and solitons in a sampled analog link, we perform thorough measurements of the analog link metrics to compare their performance and study the effect of the combs' conversion efficiency. Finally, we report on our progress towards integrating atomic-optical clocks, where we experimentally generate on-chip octave-spanning solitons and discuss a novel Vernier division scheme to readout the comb's large repetition rate. To address challenges imposed by the low comb-line powers, we propose a comb stabilization scheme that utilizes the clock laser for the nonlinear frequency mixing operations, relieving the need for external lasers or amplifiers.
National Science Foundation under award number 1839191-ECCS.
U.S. Office of Naval Research under Award N00173-19-1-G900.
National Science Foundation under grant 1809784-ECCS.
Saudi Arabian Cultural Mission (SACM) and King Saud University Scholarship