Fiber-optic communications with microresonator frequency combs
Doctoral thesis, 2018

Modern data communication links target ever-higher information throughput. To utilize the available bandwidth in a single strand of fiber, optical communication links often require a large number of lasers, each operating at a different wavelength. A microresonator frequency comb is a chip-scale multi-wavelength laser source whose spectrum consists of multiple evenly spaced lines. As the line spacing of a microresonator comb is on the order of several tens of GHz, it provides a promising light source candidate for implementing an integrated multi-wavelength transceiver. The interest for using microresonator combs in communications applications has therefore increased greatly in the last five years. The application-related developments have been complemented with an increased exploration and understanding of the operating principles behind these devices.

This thesis studies microresonator frequency combs in both long-haul and high data-rate (multi-terabit per second) fiber communications systems. The results specifically include the longest demonstrated communications link with a microresonator light source as well as the highest order modulation format demonstration using any integrated comb source. The used microresonators are based on a high-Q silicon nitride platform provided by our collaborators at Purdue University. Part of the results are enabled by the high line powers resulting from a recently demonstrated novel comb state. This state bears similarities with dark solitons in fibers in that it corresponds to a train of dark pulses circulating inside the microresonator cavity. Overall, the results in this thesis provide a promising pathway towards enabling a future chip-scale multi-wavelength coherent transmitter.

Kollektorn, MC2
Opponent: Prof. Kerry Vahala, Applied Physics, California Institute of Technology (Caltech), USA


Attila Fülöp

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

Long-haul coherent communications using microresonator-based frequency combs

Optics Express,; Vol. 25(2017)p. 26678-26688

Journal article

Frequency noise of a normal dispersion microresonator-based frequency comb

Optics InfoBase Conference Papers,; (2017)p. W2A.6-

Paper in proceeding

Active feedback stabilization of normal-dispersion microresonator combs

Optics InfoBase Conference Papers,; Vol. Part F82-CLEO_Europe 2017(2017)

Paper in proceeding

Triply resonant coherent four-wave mixing in silicon nitride microresonators

Optics Letters,; Vol. 40(2015)p. 4006-4009

Journal article

Digital communications affect our everyday lives to an extraordinary extent. The Internet spans topics from entertainment and news consumption to personal communications as well as easing banking and long-distance business relations. While ever-faster Internet connections and data throughputs are required, energy consumption and price rises are not typically accepted. Suggested solutions and future targets therefore often include some form of chip-scale engineering to enhance mass-producibility and power efficiency. This thesis covers the multi-colored light sources needed to enable high-capacity optical communication links. It is possible to replace a large set of lasers with a chip-scale microresonator frequency comb. The publications presented in this thesis include both long-distance and high-data rate demonstrations where this device type enables modern and future-type communication channels. With these experiments, we have shown that microresonator combs can compete for state-of-the-art Tbit/s-scale optical communications applications.

Areas of Advance

Information and Communication Technology

Nanoscience and Nanotechnology

Subject Categories


Atom and Molecular Physics and Optics

Communication Systems

Nano Technology



Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4393

Technical report MC2 - Department of Microtechnology and Nanoscience, Chalmers University of Technology: 381



Kollektorn, MC2

Opponent: Prof. Kerry Vahala, Applied Physics, California Institute of Technology (Caltech), USA

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