Figure 8
From: Efficient, high-power, narrow-linewidth, continuous-wave quantum-dot semiconductor comb laser

Setup for RIN measurement showing clockwise from top left the FP comb laser with drive and absorber bias sections, a free space isolator and fiber coupler (in a laser butterfly package), a 10/90 splitter with an OSA and a semiconductor optical amplifier (SOA), a circulator with a tunable free-space grating filter, a 10/90 splitter with a second OSA, a 10/90 splitter with a power monitor and a high-speed photodetectorwith a chirped fiber bragg grating reflector, a high-speed MZI (24 GHz) driven by a signal oscillator (OSC) for down-conversion of the comb beat frequency, a 10/90 splitter with a power monitor (PM) and variable optical attenuator (VOA) followed by a high-speed photodetector and an electrical spectrum analyzer (ESA). PM fibers used (blue lines).