Frequency Noise in Widely Tunable Lasers for Coherent Communication
The objectives of this thesis are to measure the frequency noise of a widely tunable semiconductor laser, determine the main causes for the frequency uctuations and investigate the requirements for laser frequency noise for mQAM modulation formats by means of simulations. The following theoretical a...
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KTH, Skolan för informations- och kommunikationsteknik (ICT)
2013
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ndltd-UPSALLA1-oai-DiVA.org-kth-1432092018-01-12T05:12:36ZFrequency Noise in Widely Tunable Lasers for Coherent CommunicationengFrekvensbrus hos mycket avstämbara lasrar för koherent kommunikationDascalu, Gabriela CristinaKTH, Skolan för informations- och kommunikationsteknik (ICT)2013Computer and Information SciencesData- och informationsvetenskapThe objectives of this thesis are to measure the frequency noise of a widely tunable semiconductor laser, determine the main causes for the frequency uctuations and investigate the requirements for laser frequency noise for mQAM modulation formats by means of simulations. The following theoretical aspects are covered: the derivation of the frequency noise spectrum and the detuned loading effect from the rate equations; the shape and the causes of the frequency noise power spectral density; the derivation of the linewidth spectrum from white and 1/f frequency noise; the functionality of the laser and feedback loop used for the measurements. Measurements using the feedback loop showed substantial improvements in the -3 dB laser line width, but further investigation is needed in order to obtain a laser that is suitable both as a transmitter and as a local oscillator in coherent communication. Simulations outlined the dependence of linewidth, constellation diagrams and symbol error rates on frequency noise, for BPSK, QPSK, 8PSK modulation formats and their respective differential formats. Student thesisinfo:eu-repo/semantics/bachelorThesistexthttp://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-143209TRITA-ICT-EX ; 239application/pdfinfo:eu-repo/semantics/openAccess |
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English |
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Computer and Information Sciences Data- och informationsvetenskap |
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Computer and Information Sciences Data- och informationsvetenskap Dascalu, Gabriela Cristina Frequency Noise in Widely Tunable Lasers for Coherent Communication |
description |
The objectives of this thesis are to measure the frequency noise of a widely tunable semiconductor laser, determine the main causes for the frequency uctuations and investigate the requirements for laser frequency noise for mQAM modulation formats by means of simulations. The following theoretical aspects are covered: the derivation of the frequency noise spectrum and the detuned loading effect from the rate equations; the shape and the causes of the frequency noise power spectral density; the derivation of the linewidth spectrum from white and 1/f frequency noise; the functionality of the laser and feedback loop used for the measurements. Measurements using the feedback loop showed substantial improvements in the -3 dB laser line width, but further investigation is needed in order to obtain a laser that is suitable both as a transmitter and as a local oscillator in coherent communication. Simulations outlined the dependence of linewidth, constellation diagrams and symbol error rates on frequency noise, for BPSK, QPSK, 8PSK modulation formats and their respective differential formats. |
author |
Dascalu, Gabriela Cristina |
author_facet |
Dascalu, Gabriela Cristina |
author_sort |
Dascalu, Gabriela Cristina |
title |
Frequency Noise in Widely Tunable Lasers for Coherent Communication |
title_short |
Frequency Noise in Widely Tunable Lasers for Coherent Communication |
title_full |
Frequency Noise in Widely Tunable Lasers for Coherent Communication |
title_fullStr |
Frequency Noise in Widely Tunable Lasers for Coherent Communication |
title_full_unstemmed |
Frequency Noise in Widely Tunable Lasers for Coherent Communication |
title_sort |
frequency noise in widely tunable lasers for coherent communication |
publisher |
KTH, Skolan för informations- och kommunikationsteknik (ICT) |
publishDate |
2013 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-143209 |
work_keys_str_mv |
AT dascalugabrielacristina frequencynoiseinwidelytunablelasersforcoherentcommunication AT dascalugabrielacristina frekvensbrushosmycketavstambaralasrarforkoherentkommunikation |
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1718606364604891136 |