Confining Light in 3-D Space
New communication technology such as ultra-wideband and 5G is increasing the demand for Photonic Integrated Circuits (PIC). PIC was thought of as being a planar structure that can only guide light in a single plane but research from Dr. Gao Hongwei, from the Singapore University, shows that PIC can be 3-D structures that can guide light in two planes.
PIC manufacturing is done through multiphoton lithography, which uses a femtosecond light source incident on a photosensitive material where the two-photon absorption causes the photosensitive material to polymerize and that allows for the desired structure or pattern to be formed. Below is a visual of how a femtosecond laser pulse can be used for two-photon polarization. Dr. Hongwei and his group created a spiral and air-bridge configuration which can be seen in the published paper ‘High-Resolution 3D Printed Photonic Waveguides’ .
The benefit of PIC is the improvement of current technology, for example, PIC is shown to have a 1.6 dB loss while current industry circuits experience a 1 dB loss with extremely complex and labor-intensive circuits. Other benefits of PIC waveguides is that it is shown to have an error-free 30Gbps Non-Return-to-Zero and 56 Gbps Pulse Amplitude Modulation level 4 data transmission . This is an important achievement in telecommunication systems because these highspeed benchmarks are used in current telecommunication systems, meaning that these 3D PIC can be integrated immediately into existing systems.