Fig. 6
From: Ultrafast perturbation maps as a quantitative tool for testing of multi-port photonic devices
Illustration of the experimental setup. Infrared probe pulses are grating-coupled into the waveguide, travel through the device and are then out-coupled by another grating. The transmitted light is collected by an optical fiber and the transmission is recorded by an InGaAs photodetector connected to a lock-in amplifier. The pump pulses are incident perpendicular to the device’s surface, and the delay time between the two pulses is controlled via a variable time delay stage. The pump focusing objective is mounted to a 3D piezo stage which allows the pump spot to be focused and scanned over the device
