Fabrication and characterization of low-cost optical waveguides using recycled expanded polystyrene (EPS) as core material

This study aimed to explore fabrication of optical waveguides using recycled expanded polystyrene (EPS) as the core material. The recycling process was performed by heating EPS inside the furnace for 2 h, with temperature varying from 200 °C to 280 °C. Refractive index measurement showed that EPS heated at temperature of 200 (EPS200) and 210 (EPS210) exhibited the highest refractive index. Waveguides were fabricated using polymethylmethacrylate (PMMA) sheet as a cladding layer. This sheet was engraved with CNC engraving machine to form a groove at cross-section of 1 × 1 mm 2 filled with EPS. Furthermore, characterizations were conducted to investigate propagation loss (PL), temperature-dependent loss (TDL), operating temperature, and time-dependent loss. The results showed that waveguides from EPS200 and EPS210 had the lowest power loss of 3.38 dB and 4.13 dB, respectively, measured at a wavelength of 660 nm. In terms of PL, the fabricated waveguide showed comparable values of 3.46 dB/cm and 3.79 dB/cm for EPS200 and EPS210, respectively. TDL was 7.87 × 10 -2 dB/ o C and 4.06 × 10 -2 dB/ o C for EPS200 and EPS210, respectively. Under cyclic temperature loading, waveguides could withstand up to 60 °C. Meanwhile, for prolonged exposure at temperature of 40 °C, there were no significant alterations in terms of power loss.