Title: Graphene oxide-polyvinyl alcohol film in micro cavity for optical comb filter generation

Authors: Siti Nur Fatin Zuikafly; Harith Ahmad; Suhaidi Shafie; Hong Ngee Lim; Fauzan Ahmad

Addresses: Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, 54100 Kuala Lumpur, Malaysia ' Photonics Research Centre, Department of Physics, University of Malaya, 50603 Kuala Lumpur, Malaysia ' Faculty of Engineering, Department of Electrical and Electronic Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia ' Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia ' Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, 54100 Kuala Lumpur, Malaysia

Abstract: An optical comb filter which is usually based on low pass characteristics is an excellent component for removing unwanted noise from high frequency spectra in data transmissions and signal processing. A simple interferometric based micro-cavity is proposed to generate an optical comb filter. Graphene oxide (GO)-polyvinyl alcohol (PVA) film was fabricated through a modified Hummer's method from graphite flakes. A micro cavity with a Fabry-Perot interferometer is supplied with an amplified spontaneous emission (ASE) through a single mode optical coupler. The comb filter started to form as the distance was set to over 100 μm owing to the interference effect in the micro cavity as the Fabry-Perot interferometer configuration was used to vary the distance from the fibre tip. The free spectral range, extinction ratio, quality factor, and finesse of the generated comb were recorded from 100 μm up to 400 μm, with the 400 μm distance exhibiting a more stable and efficient comb. The micro cavities parameters were compared with those with no GOPVA and both outputs were recorded. At 400 μm, GO-PVA film generated the most stable optical comb filter of free spectral range, extinction ratio, quality factor, and finesse of 1.94 nm, 11.74 dB, 997.54, and 1.24, respectively. With the advantage of the hydrophilic nature of GO, the device can be implemented in humidity sensor applications.

Keywords: optical comb filter; graphene oxide; modified Hummer's method; humidity sensing; Fabry-Perot interferometer.

DOI: 10.1504/IJNT.2020.112382

International Journal of Nanotechnology, 2020 Vol.17 No.11/12, pp.787 - 794

Published online: 13 Jan 2021 *

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