Dispersion measurements of fiber-optic components and applications of a novel tunable filter for optical communications

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Niemi, Tapio
dc.date.accessioned 2012-02-10T09:22:14Z
dc.date.available 2012-02-10T09:22:14Z
dc.date.issued 2002-06-14
dc.identifier.isbn 951-22-5986-9
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/2184
dc.description.abstract Optical communications has experienced a rapid development during the last decade. More bandwidth can be acquired by decreasing the spacing of the optical channels or by increasing the data rate. Characterization of the optical components and active monitoring of the network calls for accurate measurement methods. The objective of this thesis is to investigate and develop measurement methods and instruments for measuring important parameters of the components used in optical communications. Chromatic dispersion of optical fibers and frequency chirp of the laser transmitters set limits for the data rate and transmission distance. Measurements of dispersion have traditionally been performed using a phase-shift method. When high modulation frequencies are applied to achieve high resolution an error could be introduced. In this thesis, the measurement accuracy of this method is analyzed in detail and a novel method for estimating the accuracy and correcting the measurement result is developed. A Fabry-Perot interferometer finds numerous applications in many fields of optics. In this thesis, tunable Fabry-Perot etalon filters made of silicon were developed and several applications for these devices are demonstrated. A new device for measurements of time-resolved frequency chirp of directly modulated laser diodes in real time is developed. Interaction between the dispersion and frequency chirp limits the use of directly modulated lasers in long-haul optical links. Another application is monitoring of the wavelength of optical transmitters. The wavelength of the laser diode may shift due to aging and active monitoring and controlling of the wavelength is required. In addition, the filter improves the performance of the directly modulated transmitter by temporal reshaping of the pulses. The filter is also applied in reducing the frequency chirp of gain-switched pulses generated with a diode laser. These pulses can then be made transform limited and can for example be used in generation of optical solitons. Finally, the etalon is employed in realization of a compact wavelength reference for calibration of the wavelength scale of the optical spectrum analyzers and wavemeters. The transmission spectrum of the etalon consists of equidistant fringes. Each of these fringes can be applied as an accurate reference over a large wavelength range once the temperature of the filter is stabilized. This reference was developed to be automatic and it has an adequate accuracy for performing calibrations of field instruments. en
dc.format.extent 48, [34]
dc.format.mimetype application/pdf
dc.language.iso en en
dc.publisher Helsinki University of Technology en
dc.publisher Teknillinen korkeakoulu fi
dc.relation.haspart T. Niemi, M. Uusimaa, and H. Ludvigsen, Limitations of phase-shift method in measuring dense group delay ripple of fiber Bragg gratings, IEEE Photonics Technology Letters, Vol. 13, pp. 1334-1336, 2001. [article1.pdf] © 2001 IEEE. By permission.
dc.relation.haspart G. Genty, T. Niemi, and H. Ludvigsen, New method to improve the accuracy of group-delay measurements using the phase-shift technique, Optics Communications, Vol. 204, pp. 119-126, 2002. [article2.pdf] © 2002 Elsevier Science. By permission.
dc.relation.haspart T. Niemi, S. Tammela, T. Kajava, M. Kaivola, and H. Ludvigsen, Temperature-tunable silicon-wafer etalon for frequency chirp measurements, Microwave and Optical Technology Letters, Vol. 20, pp. 190-192, 1999.
dc.relation.haspart T. Niemi, S. Tammela, and H. Ludvigsen, Device for frequency chirp measurements of optical transmitters in real time, Review of Scientific Instruments, Vol. 73, pp. 1103-1107, 2002. [article4.pdf] © 2002 American Institute of Physics. By permission.
dc.relation.haspart T. Niemi, J-G. Zhang, and H. Ludvigsen, Effect of optical filtering on pulses generated with a gain-switched DFB laser, Optics Communications, Vol. 192, pp. 339-345, 2001. [article5.pdf] © 2001 Elsevier Science. By permission.
dc.relation.haspart T. Niemi, M. Uusimaa, S. Tammela, P. Heimala, T. Kajava, M. Kaivola, and H. Ludvigsen, Tunable silicon etalon for simultaneous spectral filtering and wavelength monitoring of a DWDM transmitter, IEEE Photonics Technology Letters, Vol. 13, pp. 58-60, 2001. [article6.pdf] © 2001 IEEE. By permission.
dc.subject.other Electrical engineering en
dc.title Dispersion measurements of fiber-optic components and applications of a novel tunable filter for optical communications en
dc.type G5 Artikkeliväitöskirja fi
dc.description.version reviewed en
dc.contributor.department Department of Electrical and Communications Engineering en
dc.contributor.department Sähkö- ja tietoliikennetekniikan osasto fi
dc.subject.keyword wavelength division multiplexing en
dc.subject.keyword optical communications en
dc.subject.keyword fiber-optic components en
dc.subject.keyword dispersion measurements en
dc.subject.keyword Fabry-Perot etalon en
dc.subject.keyword tunable optical filters en
dc.identifier.urn urn:nbn:fi:tkk-001549
dc.type.dcmitype text en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.type.ontasot Doctoral dissertation (article-based) en
dc.contributor.lab Metrology Research Institute en
dc.contributor.lab Mittaustekniikan laboratorio fi


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