Fiber-to-Waveguide Alignment Assisted by a Transparent Integrated Light Monitor

A novel fiber-to-waveguide alignment technique assisted by a transparent integrated light monitor is presented. The waveguide power is measured near the chip input facet by the contactless integrated photonic probe, which provides a feedback electrical signal steering the fiber positioning system. Automated single fiber to silicon nanowaveguide coupling is demonstrated with 40-nm resolution in a time scale of few seconds. The presented approach makes the fiber alignment procedure independent of the optical circuit integrated on the photonic chip, avoiding the need for simultaneous alignment of an output fiber, and thus easing optical chip characterization, wafer-level testing, and packaging of photonic devices.