Research

<h2>Force-Spoc collaboration</h2>
<h3>Integrated WDM Transmitters for Ultra-High Capacity Datacenter Connectivity (iTRAN)</h3>
<p>The iTRAN (Integrated WDM Transmitters for Ultra-High Capacity Datacenter Connectivity) project is a joint effort between the research centers FORCE at Chalmers University of Technology and SPOC at the Technical University of Denmark. iTRAN aims at demonstrating high-capacity multi-wavelength transmitters for coarse and dense WDM optical interconnects by developing multi-wavelength optical sources and silicon photonic integration techniques.</p>
<h2>Long-haul optical links</h2>

<p>For a band-limited channel, there is only one way to significantly increase the spectral efficiency, and that is to apply multilevel modulation. In this project, we analyze multilevel modulation formats suitable for coherent, optical transmission. Modulation formats are optimized under ideal conditions as well as considering realistic optical impairments, such as self-phase modulation and transmitter/receiver saturation.</p>
<p>An electromagnetic carrier offers essentially four degrees of freedom in which data can be modulated: the amplitude and phase in two polarizations each. In order to maximize the data rate in a fiber-optical link, all four degrees of freedom should be exploited, which can be interpreted as four-dimensional modulation. Moreover, the transmitted power can be significantly reduced by transmitting dependent data in the four dimensions, instead of regarding them as independent, parallel subchannels. If the extra complexity can be afforded, coded modulation schemes can further improve the power efficiency with several dB at the same data rate and bandwidth. In the other extreme, there are short-link applications in which coherent transmission is too costly. E.g., developing modulation techniques for the so-called optical intensity channel has recently emerged as a promising spinoff from this project.</p>
<h4>Objectives</h4>
<ul>
<li>Derive fundamental digital communication theory for transmission over fiber-optical links</li>
<li>Design spectrally efficient modulation formats, which admit a higher bit rate in the same bandwidth</li>
<li>Develop coded modulation schemes for optical channels come as close as possible to the fundamental limits, without unreasonably high decoding complexity</li>
<li>Cooptimize coding, modulation, and detection algorithms over both polarizations</li>
</ul>
<h4>Funded by</h4>
<ul>
<li><a rel="noopener" href="https://www.vr.se/" target="_blank" title="Vetenskapsrådet - vr.se (opens in new window)">Vetenskapsrådet (VR)</a></li>
<li><a rel="noopener" href="https://www.vinnova.se/" target="_blank" title="Vinnova - Sveriges innovationsmyndighet - vinnova.se (opens in new window)">VINNOVA</a></li>
</ul>
<h4>Project members</h4>

<p><strong>Cristian Bogdan Czegledi</strong><br />PhD student, Electrical engineering</p>

<p>Optical amplifiers are essential building blocks in many areas of research and in several applications. For example, in optical communication systems, which constitute the backbone of the Internet, they compensate loss induced by the transmission fiber ensuring signal integrity of the information being transmitted. The purpose of this project is to explore fundamentally new aspects and applications of optical phase-sensitive amplifiers (PSAs). PSAs are truly unique in the sense that they are the only known optical amplifiers that can achieve a quantum-limited noise figure (NF) of 0 dB, i.e. noiseless amplification.</p>
<p>We will leverage our world-leading expertise in optical fiber-based PSAs. We have previously focused on understanding the fundamental principles of PSAs and studied their impact in fiber-optic communication systems. We are now placed in a unique position to give a significant leap forward in this research field by exploring fundamentally new concepts and technology platforms, and utilize them in scenarios beyond the realm of optical communications.</p>
<p>More specifically, we will address questions such as: How would a laser based on a noiseless gain medium behave? In addition to the frequency, can the space dimension of light be amplified in a phase-sensitive manner? How can they improve quantum communications?</p>
<p>In order to address these questions, we will investigate new nonlinear waveguide structures different than those currently mostly used (optical fibers) to serve as the nonlinear element for amplification.</p>
<p>More specifically, we aim to study:</p>
<ul>
<li>Compact and high-performance nonlinear platforms for PSAs and other applications.</li>
<li>Devices enabled by PSAs including ultralow noise lasers and broadband amplifiers.</li>
<li>New optical amplification approaches for spatial division multiplexed systems.</li>
<li>Few-photon nonlinear optics and quantum communications.</li>
</ul>
<p>The significance of this project is that we will push forward with research on a new platform of optical amplifiers, which due to its generic feature of in principle being implementable at any wavelength, allows a very broad range of potential applications also outside the field of conventional optical transmission. Thus, this project can be expected to be an incubator for new and often cross-disciplinary (and sometimes unexpected) research areas. Much of the proposed work is exploratory, with aspects never studied before and with large potential benefits.</p>
<h4>Funded by</h4>
<p>Swedish Research Council (VR) (Public, Sweden)</p>
<h4>Project members</h4>

<p><strong>Ravikiran Kakarla</strong><br />PhD student, Microtechnology and Nanoscience, Photonics Laboratory</p>

<h2>Microcombs</h2>
<p><a rel="noopener" href="https://research.chalmers.se/en/project/8456" target="_blank" title="Research Chalmers - research.chalmers.se (opens in new window)">Dark-Soliton Engineering in Microresonator Frequency Combs (DarkComb)</a><br />Research project, 2018-2023</p>
<p><a rel="noopener" href="https://research.chalmers.se/en/project/9141" target="_blank" title="Research Chalmers - research.chalmers.se (opens in new window)">MICROCOMB</a><br />Research project, 2019-2022</p>
<p><a rel="noopener" href="https://research.chalmers.se/en/project/9883" target="_blank" title="Research Chalmers - research.chalmers.se (opens in new window)">Multidimensional coherent communications with microcombs</a><br />Research project, 2020-2026</p>

<h2>Publications</h2>
<p>A large number of publications are written every year by members of FORCE.</p>
<p>Chalmers is using the Open Access Policy since 2010-01-01. You will therefore find full-text copy of the publications in research.chalmers.se. You can also use the search functionality provided to refine the list of publications</p>

https://research.chalmers.se/en/organization/?tab=publications&query=Persons.PersonData.IdentifierCid:%22agrell%22+OR+Persons.PersonData.IdentifierCid:%22andrekso%22+OR+Persons.PersonData.IdentifierCid:%22andersla%22+OR+Persons.PersonData.IdentifierCid:%22magkar%22+OR+Persons.PersonData.IdentifierCid:%22perla%22+OR+Persons.PersonData.IdentifierCid:%22larssv%22+OR+Persons.PersonData.IdentifierCid:%22alexandre%22+OR+Persons.PersonData.IdentifierCid:%22johangus%22+OR+Persons.PersonData.Identifi

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Force

Research Force

Force-Spoc collaboration

Integrated WDM Transmitters for Ultra-High Capacity Datacenter Connectivity (iTRAN)

Long-haul optical links

Advanced modulation and coding

Phase-sensitive amplifiers

Noiseless phase-sensitive optical amplifiers and their applications

Microcombs

Publications

Chalmers Research