Development of a 3D thin film polymer structure for low-cost coupling of high-speed lasers and photodiodes.

In order to make the optoelectronic devices work with high data rates, there dimension must be shrunk down. For instance, smaller the active area of the photodetector, larger is the bandwidth you are utilizing, thereby increasing the data rate. Which is the main direction for nowadays and for the near future for short- and long-range optical communications. However, direct contact between those devices results in high loss according to their sizes inequality. Consequently, we developed a structure which acts as an intermediary device to reduce the loss due to mismatching. This thesis aims to improve the optical efficiency between optical fibers and such high speed optoelectronic components like VCSEL lasers and photodetectors with very small aperture diameters of 10 × 10µm^2; 5 × 5µm^2, providing the possibility of exploiting a collective and passive coupling structure based on 3D thin film from SU-8 polymer materials. Guiding the light such that is sufficiently compressed and propagates through this 3D polymer structure with high quality to the receiving device. I performed measurements and simulations using the beam propagation method to optimize the coupling efficiency, increase the tolerance to misalignment and obtain an understanding of how varying such parameters affects the optical coupling performance. A novel solution technique called “Icon Technology” has been implemented and showed high optical coupling performance between single mode fiber (G652.D) at λ = 1.55µm, with small active areas of photodetectors, showing special interest according to its low cost for high data rates applications such as datacom and telecom sectors. Deep investigations and analysis have been utilized on the proposed polymer taper structure by optimizing its dimensions, in order to have improvements on optical coupling efficiency and on the misalignment tolerance.