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A programmable passive amplifier based on temporal self-imaging (Talbot) effect and application.


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Jeon, Jinwoo (2018). A programmable passive amplifier based on temporal self-imaging (Talbot) effect and application. Mémoire. Québec, Université du Québec, Institut national de la recherche scientifique, Maîtrise en télécommunications, 108 p.

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The temporal Talbot effect, also referred to as temporal self-imaging effects (TSI) is observed when a periodic pulse train propagates through a first-order dispersive medium. Under specific dispersion conditions, either an exact or a repetition-rate multiplied self-image of the input signal is reproduced at the output. Moreover, the TSI possesses an interesting self-restoration capability, which proves effective even when acting over an aperiodic train of pulses. Besides its compelling interest as a physical phenomenon, the TSI has additionally been put into practice in several areas. This work targets application of TSI in two different fronts, namely for signal intensity amplification and for clock recovery in telecommunication systems, with a focus on optical-domain waveform processing. On the one hand, signal intensity amplification is an essential process in plentiful of applications, including for initiating physical processes, diagnostics, sensing, communications and measurement, just to name a few. On the other hand, clock recovery (CR) from data coded signals is a fundamental functionality to establish the needed synchronization in high-speed telecommunication links and signal-processing platforms, including systems based on optical signals. In these two applications, the notion of programmability is of fundamental importance. To begin with, it is obvious that for any amplification system, the capability of tuning the amplifier gain is crucial for a practical, real-world use of the amplifier. In regards to the CR problem, it should be noted that it is often desired to have access to the capability of recovering a clock signal (e.g., periodic pulse train), synchronized with the incoming data packet, with a pulse rate either identical to the symbol rate of the data signal (base-rate CR, or BR-CR) or at a divided rate with respect to the input data (sub-harmonic CR, or SH-CR). SH-CR is particularly interesting in the context of time-division multiplexing systems. The capability of tuning the clock rate with respect to the input data provides an additional important versatility in the telecommunication or signal-processing platform at hand. An advanced new feature of TSI, referred to as inverse temporal self-imaging (I-TSI), has been recently reported that enables to obtain a self-image of an incoming periodic temporal waveform (e.g., optical pulse train) but with a divided repetition rate. This is achieved through a lossless process that incorporates a suitably designed temporal phase-modulation stage before the dispersive medium. I-TSI has been demonstrated for passive amplification of repetitive optical waveforms, as induced by a lossless repetition-rate division of the incoming waveform, as well as to recover the sub-harmonic clock signal from pulsed telecommunication data signals. Unfortunately, in previous designs for passive waveform amplification and sub-harmonic clock recovery based on I-TSI, a different gain factor or a different clock rate-division factor required the use of a different amount of dispersion, a significant and unpractical modification in the amplifier setup. The possibility of achieving a reconfigurable gain factor or rate division factor in these systems constitutes the central scope of this work. In this context, the main contribution reported in this thesis resides in the derivation of a non-trivial generalization of the I-TSI equations (i.e., designing equations for the phase modulation and dispersive stages), which allow us to obtain a relatively wide range of different gain factors, or the associated rate-division factors, using a fixed dispersion, by suitably programming the temporal phase modulation step. Such a reconfigurability can be achieved by electronic means using an electro-optic phase modulator for implementation of the temporal phase modulation step. Experimental results are reported to validate the newly proposed design for passive Talbot amplification of repetitive optical waveforms in which the gain factor can be electrically reconfigurable. An all-fiber design is also demonstrated for a programmable base/sub-harmonic optical clock recovery circuit from pulsed (return-to-zero, RZ) telecommunication data signals, in which the divided clock rate can be electrically reconfigurable as well.

Type de document: Thèse Mémoire
Directeur de mémoire/thèse: Azaña, José
Mots-clés libres: télécommunications
Centre: Centre Énergie Matériaux Télécommunications
Date de dépôt: 29 janv. 2019 15:59
Dernière modification: 29 janv. 2019 15:59
URI: http://espace.inrs.ca/id/eprint/7644

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