Optimization of vertical coupling induced by 45° micro-mirrors in double-layer polymer optical waveguides with CO 2 laser smoothing
Year: 2024
Type: article
Abstract: The vertical coupling performance induced by 45° micro-mirrors in double-layer polymer optical waveguides is enhanced through CO 2 laser smoothing. The optimal double- layer waveguides were designed via ray-tracing simulation. The results show that the minimum vertical coupling loss is 0.28 dB for the upper-layer waveguide and 0.40 dB for the lower-layer waveguide with a core size of 42 µm × 42 µm. A vertical coupling model considering the roughness of 45° micro-mirrors indicates that the surface roughness should be less than 100 nm to ensure a vertical coupling loss of less than 1 dB. The 45° micro-mirrors in double-layer polymer optical waveguides were fabricated using a combination of ultraviolet lithography and stepped laser-ablation method. CO 2 laser smoothing at 0.6 W for 40 s reduces the average roughness of the micro-mirrors by 16.67 nm. The vertical coupling loss induced by the micro- mirrors treated with CO 2 laser smoothing was measured as 2.89 dB at 850 nm and 1.29 dB at 1310 nm using a 50-µm core multi-mode fiber receiver. This is significantly lower than the average vertical coupling loss of 5.47 dB at 850 nm and 2.50 dB at 1310 nm induced by untreated 45° micro-mirrors. This straightforward and effective method for fabricating and optimizing 45° micro-mirrors holds significant potential for application in vertical coupling within optical printed circuit board (OPCB) interconnection technologies.
Source: Optics Express
DOI: 10.1364/oe.533232
Language: English
Topic: Photonic and Optical Devices
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,270
Awards: G4421024858, G8759337311
OpenAlex ID: W4402380310