The authors report on the first demonstration of mode locking in an active waveguide laser manufactured by femtosecond laser writing. The active waveguide is fabricated in an Er-Yb-doped phosphate glass, and the mode locker ...

We propose a method to track signals from quadrant photodiodes (QPDs) in heterodyne laser interferometers that employ digital phase-locked loops for phase readout. Instead of separately tracking the four segments from the ...