The operation speed of high-performance computers has increased dramatically over the last decades. For sustaining their growth, multimode fiber (MMF) links have been gradually deployed, and on-board interconnection is the next step. Polymer optical waveguides (POWs) have been expected as one of the key components for on-board interconnects: they are expected to connect the light source/ photo detector on-board and an MMF off-board.
As a unique fabrication method for POWs, we developed the Mosquito method to obtain graded index (GI) circular core polymer waveguides and confirmed their low propagation loss compared to conventional step-index (SI) core waveguides. However, the connection loss of the light source to waveguide, and the waveguide to an MMF is a concern: insertion of the polymer waveguide between the light source and MMF would increase the optical loss.
So, in this paper, a tapered GI core polymer waveguide is proposed for reducing the connection loss between the laser sources and fibers/waveguides by inserting it between the source and MMF.
In the Mosquito method, a liquid core monomer is dispensed from a thin needle attached to a syringe into a cladding monomer, using a microdispenser. Hence, the core diameter is axially varied by changing the needle-scan velocity.
First, the optimum refractive index profiles in the tapered core are theoretically predicted using the BPM method. Next, the refractive index profile formed in the core during the Mosquito method is also estimated by solving the Fick’s diffusion equation. Finally, we successfully fabricate a GI tapered core polymer waveguide as designed.
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