@inproceedings{788176d8d0ea4455bd814b7d0ef43741,
title = "Low-loss delay lines with small footprint on a micron-scale SOI platform",
abstract = "Long and yet compact spiral waveguides based on micron-scale silicon strip waveguides has been enabled very recently by the introduction of the Euler bends. By ensuring effective broadband single mode operation of otherwise highly multimodal waveguides, these bends can have very low losses (<0.01 dB/90°) even with effective radii of a few microns. Together with the low propagation losses (< 0.15 dB/cm) of micron-scale strip waveguides, these bends enable centimeter-long delay lines with negligible losses and very small foot-print (< 1 mm2). In particular, interferometers delayed by ≈ 1 cm long spirals on one of the two arms have been fabricated on SOI wafers with both 3 um- and 4 umthick silicon layer, based on the well assessed process developed by VTT. The full devices have footprint smaller than 1.5 mm2, and they have been measured to have extinction ratios < 15 dB (reaching up to 21 dB) and about 3 dB excess losses. Functional characterization of the delayed interferometers at about 10 Gbps through demodulation of pseudorandom Differential Phase Shift Keying signals led to clearly opened eye diagrams with Q factor of 8.6 and bit error rates lower than 10-15.",
keywords = "delay lines, delayed interferometers, DPSK demodulation, integrated optics, photonic integrated circuits, silicon photonics, spiral waveguides",
author = "Matteo Cherchi and Mikko Harjanne and Konstantinos Vyrsokinos and Sami Ylinen and Markku Kapulainen and Tapani Vehmas and Timo Aalto",
year = "2015",
month = feb,
day = "27",
doi = "10.1117/12.2079560",
language = "English",
isbn = "978-1-6284-1457-8",
series = "Proceedings of SPIE",
publisher = "International Society for Optics and Photonics SPIE",
editor = "Reed, {Graham T.} and Watts, {Michael R.}",
booktitle = "Silicon Photonics X",
address = "United States",
note = "Silicon Photonics X, SPIE OPTO ; Conference date: 09-02-2015 Through 12-02-2015",
}