Silicon Photonics Test and Alignment

With the advantages, this new technology also brings about several production challenges, including the need for test platforms for testing of wafers / components prior to wafer dicing, analogous to conventional electrical-test wafer probing, but in the optical domain. Similarly, downstream packaging processes are more exacting and complex than ever.

Read IBM article “Silicon Integrated Nanophotonics Technology: from the Lab to the Fab”.

Since many classes of components have one or more inputs plus one or more outputs, and each of these needs to be aligned to nanoscale accuracies in order for test or packaging processes to proceed, it quickly becomes uneconomical to use traditional alignment techniques in a sequential fashion. Plus, the multiple couplings often interact, especially in the case of short waveguides. So a global, parallel, simultaneous alignment-optimization solution is needed.

An available solution is based on with PI’s E-712 photonics alignment controller and F-131 Fast Fiber Alignment Stage, a hybrid approach, where a coarse position is approached with a compact motorized positioning device (50 nanometer resolution) integrated with a high-speed piezo nanopositioning mechanism.

The video below demonstrates the capabilities. In this demo, an in-wafer, grating-coupled waveguide device is simulated by a short length of single-mode fiber. Its input and output are coupled via lensed fibers mounted on grippers on PI’s 6-Axis-Hexapod / XYZ piezo scanner combination, controlled by the E-712 controller.