Commercialization of high-speed wireless optical transmitter module based on optical phased array chip

Abstract

Optical wireless communication (OWC) is an alternative technology to overcome RF communication, which is reaching the limit of bandwidth due to the continuous growth of communication traffic. OWC technology, which has a much higher carrier frequency than RF or mm-wave, can be a fundamental solution to meet the recent large bandwidth requirements such as 8K TV, mobility, metaverse and 6G. By using optical phased array (OPA), it is possible to implement a beam-forming OWC that steers a laser signal with high-speed modulated data in a desired direction. In particular, silicon-based OPA has many advantages in terms of size, power consumption, and steering range. In this research, we propose an optical wireless transmission system using OPA. We demonstrate 32 Gbps pseudo-random bit sequence (PRBS) data transmission based on silicon OPA by combining an electro-optic phase shifter and a thermo-optic emitter for two-dimensional beam steering by selecting suitable components for the transmitter and receiver. In order to commercialize high-speed data transmission using OPA, we further research on the optical packaging method that can modularize the developed OPA chip. We developed a new technology called direct optical wire (DOW) bonding which uses polymer to create an optical waveguide that can be fabricated in free space. This technology interconnects optical chips in a very similar way to metal wire bonding, and can solve the problems in existing optical packaging methods which is low yield, large volume, and high cost. The wireless transmission module is developed by analyzing the advantages and disadvantages of other optical packaging technologies applicable to the OPA chip. Finally, 8K video data transmission using the OPA chip based wireless optical transmission module was demonstrated for proving that it can be applied to commercial systems.