Interrogation of photonic biosensors using optical frequency combs

Markus Knoerzer, Crispin Szydzik, Guanghui Ren, Cesar S. Huertas, Sonya Palmer, Phuong Tang, Thach G. Nguyen, Lam Bui, Andreas Boes, Arnan Mitchell

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


In this contribution, we show how the stability and ease-of-use of an integrated interferometric photonic biosensor platform can be enhanced using optical frequency combs, without any necessary changes to the sensor chip design. We show that if the comb line spacing of the optical frequency comb is adjusted to be at 120° intervals of the periodic spectral response of the used Mach-Zehnder interferometer and the transmission power values of the three comb lines are recorded over time, it is possible to extract the interferometer phase linearly and continuously for every sample point. This measurement approach provides an accurate phase measurement and is independent of the interferometer bias. Furthermore, it is robust against intensity fluctuations which are common to all three used comb lines. Our demonstration uses a simple silicon photonic interferometric refractive index sensor, and we show that the benefits of our approach can be achieved without degrading the lower limit of detection of 3.70×10-7 RIU of our sensor platform. Our technique can be applied to any interferometric sensor and only requires a single input and single output and does not need any special couplers. This technique offers a drop-in replacement to the commonly used single wavelength phase measurement.

Original languageEnglish
Title of host publicationBiophotonics Australasia 2019
EditorsEwa M. Goldys, Brant C. Gibson
Place of PublicationBellingham WA USA
PublisherSPIE - International Society for Optical Engineering
Number of pages2
ISBN (Electronic)9781510631441
ISBN (Print)9781510631458
Publication statusPublished - 30 Dec 2019
EventSPIE Biophotonics Australasia 2019 - Melbourne, Australia
Duration: 9 Dec 201912 Dec 2019

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceSPIE Biophotonics Australasia 2019


  • Optical frequency comb
  • linear phase readout
  • refractive index sensor
  • Mach-Zehnder Interferometer

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