Contactless probes for PICs and packaging
Non-invasive optical monitoring enables precise fiber-to-chip alignment and scalable photonic integration.
Researchers have highlighted the potential of contactless integrated photonic probes (CLIPPs) to enable non-invasive optical power monitoring in large-scale photonic integrated circuits (PICs), offering new opportunities for silicon photonics, advanced photonic packaging and optical-electronic integration.
The technology, detailed in a review published in Frontiers of Optoelectronics, enables optical power monitoring without extracting light from waveguides, overcoming the insertion losses associated with conventional optical taps and photodetectors.
CLIPPs operate by detecting light-induced electrical conductivity changes within silicon waveguides using metal electrodes deposited above the dielectric cladding.
The approach is compatible with standard CMOS manufacturing processes and does not require additional doping or ion implantation, making it attractive for scalable silicon photonics integration.
A key application lies in advanced photonic packaging, where CLIPP technology enables automated, high-precision fiber-to-chip alignment.
By placing a probe near the input facet of a photonic chip, researchers have demonstrated single-sided fiber alignment within a few seconds, achieving a spatial precision of 40 nm without requiring optical power collection at the output.
This capability could simplify optical assembly, reduce packaging complexity and improve manufacturing throughput.
The technology also supports real-time monitoring and closed-loop stabilization of microring resonators, Mach-Zehnder interferometers and reconfigurable photonic processors.
Dedicated electronic readout circuits have demonstrated parallel monitoring of up to 32 contactless probes, highlighting the potential for scalable optical-electronic integration.
Looking ahead, further developments in sensor miniaturization, crosstalk suppression and CMOS readout integration could support the deployment of CLIPPs in next-generation photonic systems, including co-packaged optics (CPO), optical computing, telecommunications and quantum photonics.
