Detecting Spurious Reflections in Integrated Photonic Devices

Spurious reflections can be a problematic issue in integrated optical devices, such as lasers [1], detectors [2], or multi-mode interference (MMI) couplers [3]. Here we demonstrate a simple method to localize such faint reflections occurring inside the chip, using only wavelength-swept power transmission measurements. The method does not require a special measurement setup and is based on minimum phase techniques, which were recently proposed for integrated optical device characterization [4].