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UID:20260728T121720EDT-9085irt1DB@132.216.98.100
DTSTAMP:20260728T161720Z
DESCRIPTION:Abstract\n\nMicrowave photonics (MWP) is an interdisciplinary f
 ield that merges the principles of microwave engineering and photonics\, a
 iming to enhance the performance and capabilities of microwave systems. Be
 nefiting from the broad bandwidth of electro-optical modulators (EOMs) and
  photodiodes (PDs)\, the MWP system can achieve much higher operation freq
 uency than conventional digital signal processing (DSP) systems. Moreover\
 , a quantum dash (QDash) mode-locked laser (MLL) and a programable optical
  filter (waveshaper) together offers a set of stable\, programable and rec
 onfigurable optical taps. Compared to other optical frequency comb (OFC) s
 ources\, such as ring resonator and cascaded EOMs\, the motivation of usin
 g QDash MLL is its flat comb spectrum\, reasonable free spectral range (FS
 R)\, and a large number of comb lines. The flat comb spectrum can maximize
  the efficiency of comb shaping\, more comb lines offer more programmabili
 ty and flexibility\, and reasonable free spectral range enable the operati
 on frequency range for RF and mmWave signals. This thesis delves into the 
 innovative applications of MWP\, focusing on the development and optimizat
 ion of MWP filters\, reconfigurable instantaneous frequency measurement (I
 FM) systems\, arbitrary waveform generation (AWG) systems\, phased array a
 ntennas (PAAs)\, and photonic analog-to-digital converters (ADCs).\n\nThe 
 first part of the thesis introduces the fundamental concepts and structure
 s of MWP filters\, including coherent and digital finite impulse response 
 (FIR) filters. Coherent MWP filters\, though capable of achieving high cen
 ter frequencies\, face challenges in narrow transition bands. Digital FIR-
 based MWP filters\, however\, offer programmability and reconfigurability\
 , allowing for the design of arbitrarily shaped filters\, thus broadening 
 their applicability. A significant contribution of this work is the demons
 tration of a reconfigurable IFM system with linear frequency response util
 izing MWP filters based on a QDash MLL. The QDash MLL\, with its flat comb
  spectrum and sufficient OFC lines\, proves ideal for comb shaping\, enabl
 ing the system to achieve a maximum frequency range of 20 GHz and improved
  measurement accuracy of a root mean square error 30-42 MHz through an amp
 litude comparison function system.\n\nThe thesis also explores a programma
 ble MWP-AWG system\, leveraging the impulse response of MWP filters to gen
 erate various waveforms with adjustable characteristics. This system showc
 ases the flexibility and precision of MWP technologies in waveform generat
 ion\, including rectangular\, triangular and sine burst waveforms. In the 
 realm of PAAs\, the research demonstrates the use of a QDash MLL as an OFC
  source to achieve discretely tunable steering angles and beam scanning ca
 pabilities in the range of -90~90 degree (half circle) and 0~360 degree (f
 ull circle). The system benefits from uniform comb spacing and fiber dispe
 rsion\, providing effective beamforming and scanning functions. Finally\, 
 the thesis investigates photonic ADCs for RF and millimeter-wave signals\,
  presenting time-interleaved and heterodyne photonic ADCs. These ADCs exhi
 bit enhanced effective number of bits (ENOB) up to 11 across their operati
 ng frequency ranges and demonstrate their potential for advanced and real-
 time signal processing in future communication systems\, including 5G and 
 beyond.\n\nThis comprehensive study underscores the transformative potenti
 al of MWP technologies\, offering high-frequency operation\, reconfigurabi
 lity\, and advanced signal processing capabilities. The findings and devel
 opments presented in this thesis pave the way for more efficient\, flexibl
 e\, and powerful communication systems\, highlighting the promising future
  of microwave photonics in the evolution of photonic signal processing tec
 hnologies.\n
DTSTART:20241105T183000Z
DTEND:20241105T203000Z
LOCATION:Room MC437\, McConnell Engineering Building\, CA\, QC\, Montreal\,
  H3A 0E9\, 3480 rue University
SUMMARY:PhD defence of Yuxuan Xie – Applications of Quantum-Dash Mode-Locke
 d Laser in Microwave Photonics
URL:/ece/channels/event/phd-defence-yuxuan-xie-applica
 tions-quantum-dash-mode-locked-laser-microwave-photonics-360706
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