Authors:	B. Ouyang, Y. Li, M. Kruidhof, R. Horsten, K. Van Dongen, J. Caro
Title:	On-chip silicon Mach-Zehnder interferometer sensor for ultrasound detection
Format:	International Journal
Publication date:	4/2019
Journal/Conference/Book:	Optics Letters
Volume(Issue):	44(8) p.1928-1931
DOI:	10.1364/ol.44.001928
Citations:	22 (Dimensions.ai - last update: 21/4/2024) 4 (OpenCitations - last update: 19/4/2024) Look up on Google Scholar
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Abstract

A highly sensitive ultrasound sensor based on an integrated photonics Mach-Zehnder interferometer (MZI) fabricated in silicon-on-insulator technology is reported. The sensing spiral is located on a membrane of size 121  μm x 121  μm. Ultrasound waves excite the membrane's vibrational mode, which translates to modulation of the MZI transmission. The measured sensor transfer function is centered at 0.47 MHz and has a −6  dB bandwidth of 21.2%. The sensor sensitivity is linear in the optical input power and reaches a maximum 0.62 mV/Pa, which is limited by the interrogation method. At 0.47 MHz and for an optical power of 1.0 mW the detection limit is 0.38  mPa/sqrt(Hz) and the dynamic range is 59 dB. The MZI's gradual transmission function allows a wide range of wavelength operation points. This strongly facilitates sensor use and is promising for applications.