Microstructure-Based Fiber-To-Chip Coupling of Polymer Planar Bragg Gratings for Harsh Environment Applications

Abstract

This article proposes and demonstrates a robust microstructure-based fiber-to-chip coupling scheme for planar Bragg grating devices. A polymer planar Bragg grating substrate is manufactured and microstructured by means of a micromilling process, while the respective photonic structures are generated by employing a sophisticated single-writing UV-exposure method. A stripped standard single mode fiber is inserted into the microstructure, which is filled with a UV-curable adhesive, and aligned with the integrated waveguide. After curing, final sensor assembly and thermal treatment, the proposed coupling scheme is capable of withstanding pressures up to 10 bar, at room temperature, and pressures up to 7.5 bar at an elevated temperature of 120 °C. Additionally, the coupling scheme is exceedingly robust towards tensile forces, limited only by the tensile strength of the employed single mode fiber. Due to its outstanding robustness, the coupling scheme enables the application of planar Bragg grating devices in harsh environments. This fact is underlined by integrating a microstructure-coupled photonic device into the center of a commercial-grade carbon fiber-reinforced polymer specimen. After its integration, the polymer-based Bragg grating sensor still exhibits a reflection peak with a dynamic range of 24 dB, and can thus be employed for sensing purposes.

Lattice-Like Waveguides With Integrated Bragg Gratings in Planar Cyclic Olefin Copolymers

“…Besides the fact that, in comparison with polymer optical fibers, planar substrates enable utilization of COC grades with higher temperature stability, handling and post-processing of planar devices is straightforward, while injection-molded substrates are also reasonably priced if they are manufactured in large quantities. Furthermore, the inherent robustness of COC substrates enables the harsh-environment application of these devices and also their subsequent electrification via femtosecond laser-based sintering JLT-33072-2023 2 processes [16], [17]. Additionally, COC is hemocompatible and the feasibility of merging integrated photonics with microfluidics on a single COC platform is already proven, thus paving the way towards COC-based lab-on-a-chip devices [18], [19].…”

Towards pressure sensors based on polymer planar Bragg gratings

“…They can furthermore withstand temperatures up to 160 °C14 . This fact, in combination with general physical robustness of the PPBG concept, enables their usage in the outline of harsh environments or processes 15 . Thus, several COC-PPBG-based devices, for example multidimensional strain sensors 16 and hypersensitive hydrogen detectors 17 as well as optoelectronic platforms 18 , were demonstrated successfully.…”

Polymer Optical Waveguide Grating-Based Biosensor to Detect Effective Drug Concentrations of Ginkgolide A for Inhibition of PMVEC Apoptosis

“…In contrast to other waveguide structures, grating-based sensors are more suitable for high sensitivity and fast detection of label-free solution or gas [14][15][16]. In particular, polymer waveguide grating-based sensors with better manual control, more fabricating flexibility, and more targeted selection have been used to realize state-of-the-art integrated functional sensing chips [17,18]. Furthermore, polymer waveguide materials with specific functional groups are more advantageous for selecting organic adhesion monomers and capturing small drug molecules from TCM solutions by multi-hydrogen-bonding interacting effects [19,20].…”