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UID:20260728T132300EDT-6263vVmuaj@132.216.98.100
DTSTAMP:20260728T172300Z
DESCRIPTION:Abstract\n\n\n	\n		\n			\n				Microwave photonics (MWP) harnesses optical
  devices and techniques to generate\, process\, and transport microwave an
 d millimeter-wave signals. By combining ultra-wideband optoelectronic devi
 ces\, low-loss fiber distribution\, strong immunity to electromagnetic int
 erference\, and compatibility with large-scale photonic integration\, MWP 
 provides an effective route to overcome bottlenecks in purely electronic s
 ystems. These capabilities support applications including 5G/6G mobile fro
 nthaul/backhaul\, distributed coherent radar\, true-time-delay beamforming
 \, broadband instantaneous frequency measurement\, reconfigurable microwav
 e signal processing\, low-phase-noise microwave generation\, and photonic 
 AI accelerators. In this thesis\, we explore how broadband optical sources
  (BOS)\, including coherent optical frequency combs (OFCs) and non-coheren
 t amplified spontaneous emission (ASE)\, can expand the performance and ap
 plication potential of MWP\, with a focus on microwave signal processing a
 nd generation.\n\n				The first part of this thesis investigates BOS-enabled m
 icrowave photonic filters (MPFs) and signal processors based on a finite-i
 mpulse-response (FIR) framework. In these architectures\, chromatic disper
 sion introduces wavelength-dependent delays between adjacent optical carri
 ers\, forming a tapped-delay-line filter closely related to FIR filtering 
 in digital signal processing. Based on this principle\, we develop and exp
 erimentally validate a versatile MWP signal processor reconfigurable for i
 ntegral and fractional Hilbert transforms\, differentiation\, and integrat
 ion\, using OFCs generated by a quantum-dash mode-locked laser as a cohere
 nt BOS. We then address a related challenge in dispersion-based FIR implem
 entations: in real fiber links\, third-order dispersion (TOD) distorts the
  designed tap delays and degrades the processor/filter response. To solve 
 this issue\, we propose and experimentally demonstrate\, in an ASE-based a
 rchitecture\, a chirp-like spectral slicing technique that effectively rem
 oves TOD-induced impairment.\n\n				The second part further investigates ASE-d
 riven optoelectronic oscillators (OEOs) for high-quality and reconfigurabl
 e microwave generation by amplifying the MPF output and feeding it back to
  form a closed optoelectronic loop. We demonstrate a single-cavity OEO tha
 t can switch among single-frequency\, dual-frequency\, and mode-locked reg
 imes. However\, this OEO is inherently prone to multimode oscillation beca
 use the MPF passband is relatively broad while the long cavity has a small
  free spectral range (FSR)\, allowing multiple cavity modes to oscillate. 
 This reflects a long-standing OEO trade-off: a long cavity improves phase 
 noise but reduces FSR\, making single-mode oscillation difficult. To overc
 ome this trade-off\, we propose cascaded zero-dispersion recirculating loo
 ps (ZD-RLs) as auxiliary FIR filters in an ASE-driven OEO to enhance the M
 PF Q-factor. Experiments show that progressively cascading ZD-RLs improves
  the sidemode suppression ratio (SMSR) without compromising phase-noise pe
 rformance\, providing the first experimental demonstration of overcoming t
 his trade-off. Building on the strength of ZD-RLs\, we further extend the 
 approach to a broader family of OEO regimes\, including a mode-locked OEO 
 for microwave frequency-comb generation with record-high harmonic mode-loc
 king order\, a dual-frequency OEO with independently tunable tones while m
 aintaining single-mode oscillation\, and a dispersion-tuned OEO that exper
 imentally demonstrates dispersion-enabled frequency tuning in an OEO for t
 he first time.\n\n				Overall\, this thesis establishes BOS as a versatile and
  scalable enabler for MWP\, advancing both reconfigurable microwave signal
  processing and high-quality microwave generation. By addressing key pract
 ical bottlenecks\, including dispersion-induced impairments in FIR-based p
 rocessors and the long-standing mode-purity–phase-noise trade-off in long-
 loop OEOs\, we push MWP signal processors and OEOs toward real-world deplo
 yment.\n			\n		\n	\n\n
DTSTART:20260618T140000Z
DTEND:20260618T160000Z
LOCATION:Room 603\, McConnell Engineering Building\, CA\, QC\, Montreal\, H
 3A 0E9\, 3480 rue University
SUMMARY:PhD defence of Zhuoran Wang – Broadband Optical Source Empowering M
 icrowave Photonics
URL:/ece/channels/event/phd-defence-zhuoran-wang-broad
 band-optical-source-empowering-microwave-photonics-373091
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