Polymer optical bridges for efficient splicing of optical fibers

We present an application of optonumerical methodology for improvement of functional parameters of polymer optical bridges that connect two optical fibers. To fully determine and improve the properties of this kind of microstructure, experimental methods are combined with numerical modeling. The parameters describing the functionality of the polymer optical bridges are optical losses (insertion and return), which determine the usability of those elements as optical fiber splices. These parameters are the function of such features as refractive index distribution, microstructure geometry, and propagation of the light wavelength. To analyze the relation of those features on the functional parameters of the studied microstructures, the experimental results are compared to the ones obtained with simulations. Numerical modeling of the aforementioned optical bridges is performed by means of the finite-difference time-domain method. Experimental methods consist of optical diffraction tomography, which is used to obtain a full three-dimensional refractive index distribution of optical bridge, and measurement of optical losses. Implementation of the proposed methodology in iterative procedure allows the optimization of the fabrication procedure to produce efficient and reliable optical splices with desired functional parameters—insertion loss at the level of 0.2 dB and return loss above 60 dB.