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## Multiwavelength transmitters in Generic Photonic Integration Technologies

### Katarzyna Ławniczuk

#### Abstract

Indium phosphide (InP)-based photonic integration platforms are nowadays one of the most promising technologies for realization of functionally advanced and compact optical circuits. These platforms allow for light generation, ampliﬁcation, detection and fast modu- lation, and thus provide multifunctional devices for a multitude of applications. By making use of these platforms and following the generic technology concept we developed various multiwavelength transmitters. These photonic devices were fabricated via multi-project wafer runs in generic processes by an industrial foundry partner. The size of the fabricated chips is a few mm2. To design our photonic integrated circuits we took advantage of standardized and pa- rameterized photonic building blocks, such as: passive waveguide devices, semiconductor optical ampliﬁers, electro-optical phase modulators and distributed Bragg reﬂector (DBR) gratings. Our multiwavelength sources used arrayed waveguide gratings (AWGs) as multi- plexers of optical signals and as intra-cavity ﬁlters within lasers. The sources were monolith- ically integrated with electro-optical modulators in a Mach-Zehnder conﬁguration. In this research work we investigated three approaches for realizing multiwavelength transmitters: (1) AWG-laser based transmitters; (2) DBR-laser based transmitters; and (3) AWG-DBR-laser based transmitters. We proposed two conﬁgurations of the AWG-laser based transmitters, that used a novel conﬁguration of on-chip integrated Michelson interferometers for light out-coupling. These interferometers are composed of 2 × 2 multi-mode interference cou- plers (MMIs), which allowed to eliminate the 3 dB loss that would be normally introduced when using 1 × 2 MMI-couplers. In addition, Michelson interferometers provided a free choice of the out-coupling ratios. The DBR-laser based transmitters took advantage of an array of tunable DBR-based lasers. These transmitters were used to explore a generic pack- aging solution that enabled multiport DC and RF electrical access. The AWG-DBR-laser based transmitters demonstrated a novel conﬁguration of the AWG sources by utilizing a wavelength-selective DBR mirror. By implementing the DBR mirrors we could freely po- sition the on-chip reﬂectors within the photonic circuit and select the laser operation on a single free spectral range of AWG. An extended-cavity conﬁguration of these lasers re- sulted in a narrow optical linewidth (275 kHz). The proposed conﬁgurations of the trans- mitter circuits allowed for operation as 4- and 8-channel devices in the telecommunication C-band spectral range. We focused on implementation of the transmitter circuits that allow for simultaneous production of both continuous-wave pilot tones that act as a carrier for the upstream data and modulated downstream signals. The modulation speed of the de- vices reached 12.5 Gb/s per transmission channel. The devices operated with optical out- put power in the range of a few milliwatts in ﬁber, and provided error-free transmission for distances up to 50 km.
Record ID
WUT9748439182ff49f6941a962005805206
Diploma type
Doctor of Philosophy
Author
Katarzyna Ławniczuk Katarzyna Ławniczuk,, The Institute of Microelectronics and Optoelectronics (FEIT/MO)Faculty of Electronics and Information Technology (FEIT)
Title in Polish
Analiza możliwości zastosowania generycznych technologii fotoniki scalonej do wytwarzania wielokanałowych nadajników optycznych
Title in English
Multiwavelength transmitters in Generic Photonic Integration Technologies
Language
(en) English
Certifying Unit
Faculty of Electronics and Information Technology (FEIT)
Certifying University/Institution (when outside WUT)
Eindhoven University of Technology (TU/e)
Discipline
electronics / (technology domain) / (technological sciences)
Status
Finished
Defense Date
22-01-2014
Title date
22-01-2014
Supervisor
Honored
yes
Pages
1-156
Keywords in English
generic integration, multiwavelength transmitters, photonic integrated circuits
Abstract in English
Indium phosphide (InP)-based photonic integration platforms are nowadays one of the most promising technologies for realization of functionally advanced and compact optical circuits. These platforms allow for light generation, ampliﬁcation, detection and fast modu- lation, and thus provide multifunctional devices for a multitude of applications. By making use of these platforms and following the generic technology concept we developed various multiwavelength transmitters. These photonic devices were fabricated via multi-project wafer runs in generic processes by an industrial foundry partner. The size of the fabricated chips is a few mm2. To design our photonic integrated circuits we took advantage of standardized and pa- rameterized photonic building blocks, such as: passive waveguide devices, semiconductor optical ampliﬁers, electro-optical phase modulators and distributed Bragg reﬂector (DBR) gratings. Our multiwavelength sources used arrayed waveguide gratings (AWGs) as multi- plexers of optical signals and as intra-cavity ﬁlters within lasers. The sources were monolith- ically integrated with electro-optical modulators in a Mach-Zehnder conﬁguration. In this research work we investigated three approaches for realizing multiwavelength transmitters: (1) AWG-laser based transmitters; (2) DBR-laser based transmitters; and (3) AWG-DBR-laser based transmitters. We proposed two conﬁgurations of the AWG-laser based transmitters, that used a novel conﬁguration of on-chip integrated Michelson interferometers for light out-coupling. These interferometers are composed of 2 × 2 multi-mode interference cou- plers (MMIs), which allowed to eliminate the 3 dB loss that would be normally introduced when using 1 × 2 MMI-couplers. In addition, Michelson interferometers provided a free choice of the out-coupling ratios. The DBR-laser based transmitters took advantage of an array of tunable DBR-based lasers. These transmitters were used to explore a generic pack- aging solution that enabled multiport DC and RF electrical access. The AWG-DBR-laser based transmitters demonstrated a novel conﬁguration of the AWG sources by utilizing a wavelength-selective DBR mirror. By implementing the DBR mirrors we could freely po- sition the on-chip reﬂectors within the photonic circuit and select the laser operation on a single free spectral range of AWG. An extended-cavity conﬁguration of these lasers re- sulted in a narrow optical linewidth (275 kHz). The proposed conﬁgurations of the trans- mitter circuits allowed for operation as 4- and 8-channel devices in the telecommunication C-band spectral range. We focused on implementation of the transmitter circuits that allow for simultaneous production of both continuous-wave pilot tones that act as a carrier for the upstream data and modulated downstream signals. The modulation speed of the de- vices reached 12.5 Gb/s per transmission channel. The devices operated with optical out- put power in the range of a few milliwatts in ﬁber, and provided error-free transmission for distances up to 50 km.
Thesis file
• File: 1
Ławniczuk-doktorat.pdf
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Uniform Resource Identifier
https://repo.pw.edu.pl/info/phd/WUT9748439182ff49f6941a962005805206/
URN
urn:pw-repo:WUT9748439182ff49f6941a962005805206

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