Excitation of core modes through side coupling to multimode optical fiber by hydrothermal growth of ZnO nanorods for wide angle optical reception

Abstract

Side coupling to core modes through zinc oxide (ZnO) nanorods grown around the fiber is demonstrated in this work. The scheme utilizes wet etching of the cladding region followed by hydrothermal growth of the nanorods. The combination of nanostructures and the optical fiber system is used to demonstrate a simple wide field of view (FOV) optical receiver. Core modes are excited by the light scattered in the region where the fiber core is exposed. The angular response of the receiver was tested using a nephlometer. Light coupling efficiency was extracted by deconvoluting the finite beam extinction from the measured power. The results were compared to a first-order analytical model in which the phase function is assumed to linearly shift with the incident angle. The trend of the experimental measurements agrees with the model. 180°FOV is verified, and maximum coupling efficiency of around 2.5% for a single fiber is reported. Excitation of core modes through side coupling shows potential for the application of these devices in optical receivers and sensors.

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Side coupling of multiple optical channels by spiral patterned zinc oxide coatings on large core plastic optical fibers

“…Depending on its doping condition, ZnO can be conductive (including n-type and p-type conductivity), semi-conductive, insulating, transparent and show piezoelectric behaviour, room temperature ferromagnetism, and huge magneto-optic and chemical sensing properties [1]. This versatility makes ZnO a suitable material for a variety of integrated nanosystems that include optoelectronics [2][3][4][5], biosensors [6][7][8], resonators [9], medical devices [10,11], imaging [12,13], and wireless communication [14]. In optical fiber systems, light is typically introduced from one end, guided through the fiber and collected at the other end.…”