Premium
Coherency‐Broken Bragg Filters: Overcoming On‐Chip Rejection Limitations
Author(s) -
Oser Dorian,
Mazeas Florent,
Le Roux Xavier,
PérezGalacho Diego,
Alibart Olivier,
Tanzilli Sébastien,
Labonté Laurent,
MarrisMorini Delphine,
Vivien Laurent,
Cassan Éric,
AlonsoRamos Carlos
Publication year - 2019
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.201800226
Subject(s) - resonator , fiber bragg grating , filter (signal processing) , materials science , chip , waveguide , free spectral range , optics , photonics , interferometry , optical filter , fabrication , photonic integrated circuit , phase (matter) , optoelectronics , electronic engineering , physics , computer science , engineering , electrical engineering , wavelength , telecommunications , medicine , alternative medicine , pathology , quantum mechanics
Selective optical filters with high rejection levels are of fundamental importance for a wide range of advanced photonic circuits. However, the implementation of high‐rejection on‐chip optical filters is seriously hampered by phase errors arising from fabrication imperfections. Due to coherent interactions, unwanted phase‐shifts result in detrimental destructive interferences that distort the filter response, whatever the chosen strategy (resonators, interferometers, Bragg filters, etc.). State‐of‐the‐art high‐rejection filters partially circumvent the sensitivity to phase errors by means of active tuning, complicating device fabrication and operation. Here, a new approach based on coherency‐broken Bragg filters is proposed to overcome this fundamental limitation. Non‐coherent interaction among modal‐engineered waveguide Bragg gratings separated by single‐mode waveguides is exploited to yield effective cascading, even in the presence of phase errors. This technologically independent approach allows seamless combination of filter stages with moderate performance free of active control, providing a dramatic increase of on‐chip rejection. Based on this concept, on‐chip non‐coherent cascading of Si Bragg filters is experimentally demonstrated, achieving a light rejection exceeding 80 dB, the largest value reported for an all‐passive silicon filter.