Co-Packaged Optics (CPO) Edge Coupling Solutions

Edge Coupling in CPO Architecture 

Edge Coupling is another pivotal interface technology within CPO (Co-Packaged Optics) architectures, primarily responsible for efficiently interfacing optical signals from the side (End-face) of a Silicon Photonics chip with external fibers.  

Driven by the trend toward ultra-low loss in CPO systems, Edge Coupling provides a horizontal connectivity approach. Its principle involves designing a Spot-Size Converter (SSC) at the end of the silicon waveguide to expand the tiny internal optical spot to match the mode field size of the external fiber, thereby enabling direct optical coupling at a near-0° horizontal angle. 

Compared to Grating Coupling, which suffers from energy losses due to diffraction efficiency limits, Edge Coupling offers exceptionally high coupling efficiency. Its linear alignment characteristic significantly reduces insertion loss when signals enter the chip, which is critical for improving overall energy efficiency in power-sensitive CPO modules.