Optical interconnects based on VCSELs and low-loss silicon photonics

Timo Aalto, Mikko Harjanne, Mikko Karppinen, Matteo Cherchi, Aila Sitomaniemi, Jyrki Ollila, Antonio Malacarne, Christian Neumeyr

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    3 Citations (Scopus)


    Silicon photonics with micron-scale Si waveguides offers most of the benefits of submicron SOI technology while avoiding most of its limitations. In particular, thick silicon-on-insulator (SOI) waveguides offer 0.1 dB/cm propagation loss, polarization independency, broadband single-mode (SM) operation from 1.2 to >4 μm wavelength and ability to transmit high optical powers (>1 W). Here we describe the feasibility of Thick-SOI technology for advanced optical interconnects. With 12 μm SOI waveguides we demonstrate efficient coupling between standard single-mode fibers, vertical-cavity surface-emitting lasers (VCSELs) and photodetectors (PDs), as well as wavelength multiplexing in small footprint. Discrete VCSELs and PDs already support 28 Gb/s on-off keying (OOK), which shows a path towards 50-100 Gb/s bandwidth per wavelength by using more advanced modulation formats like PAM4. Directly modulated VCSELs enable very power-efficient optical interconnects for up to 40 km distance. Furthermore, with 3 μm SOI waveguides we demonstrate extremely dense and low-loss integration of numerous optical functions, such as multiplexers, filters, switches and delay lines. Also polarization independent and athermal operation is demonstrated. The latter is achieved by using short polymer waveguides to compensate for the thermo-optic effect in silicon. New concepts for isolator integration and polarization rotation are also explained.

    Original languageEnglish
    Title of host publicationOptical Interconnects XVIII
    PublisherInternational Society for Optics and Photonics SPIE
    ISBN (Electronic)978-1-5106-1561-8
    Publication statusPublished - 1 Jan 2018
    MoE publication typeA4 Article in a conference publication
    EventOptical Interconnects XVIII 2018 - San Francisco, United States
    Duration: 29 Jan 201831 Jan 2018

    Publication series

    SeriesProceedings of SPIE


    ConferenceOptical Interconnects XVIII 2018
    Country/TerritoryUnited States
    CitySan Francisco


    The results presented here were obtained from multiple projects. 1) The RAPIDO project (http://www.rapido-project.eu) was funded by the European Commission under the 7th Framework Programme with the grant agreement number 619806. 2) The OPEC project is funded by Tekes – the Finnish Funding Agency for Innovation – with the grant agreement number 2814/31/2015. 3) The PASSION project (http://www.passion-project.eu) is funded by the European Commission under the H2020 Programme with the grant agreement number 780326.


    • Faraday rotator
    • Hybrid integration
    • Long-wavelength VCSEL
    • Optical interconnect
    • Polarization independent
    • Silicon photonics
    • Silicon-on-insulator
    • Wavelength multiplexer
    • OtaNano


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