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Subwavelength grating Fourier‐transform interferometer array in silicon‐on‐insulator
Author(s) -
Bock Przemek J.,
Cheben Pavel,
Velasco Aitor V.,
Schmid Jens H.,
Delâge André,
Florjańczyk Mirosław,
Lapointe Jean,
Xu DanXia,
Vachon Martin,
Janz Siegfried,
Calvo María L.
Publication year - 2013
Publication title -
laser and photonics reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.778
H-Index - 116
eISSN - 1863-8899
pISSN - 1863-8880
DOI - 10.1002/lpor.201300063
Subject(s) - astronomical interferometer , optics , free spectral range , grating , interferometry , materials science , arrayed waveguide grating , waveguide , mach–zehnder interferometer , diffraction grating , spectrometer , planar , fourier transform , optoelectronics , wavelength , physics , wavelength division multiplexing , computer graphics (images) , quantum mechanics , computer science
A planar waveguide Fourier‐transform spectrometer with densely arrayed Mach‐Zehnder interferometers is demonstrated. Subwavelength gratings are used to produce an optical path difference without waveguide bends. The fabricated device comprises of an array of 32 Mach‐Zehnder interferometers, which produce a spatial interferogram without any moving parts, yielding a spectral resolution of 50 pm and a free‐spectral range of 0.78 nm. As a result of similar propagation losses in subwavelength grating waveguides and conventional strip waveguides, loss imbalance is minimized and high interferometic extinction ratio of −25 to −30 dB is obtained. Furthermore, phase and amplitude errors arising from normal fabrication variation are compensated by the spectral retrieval process using calibration measurements.