35GHz mode-locking of 1.3μm quantum dot lasers

35GHz passive mode-locking of 1.3μm (InGa)As∕GaAs quantum dot lasers is reported. Hybrid mode-locking was achieved at frequencies up to 20GHz. The minimum pulse width of the Fourier-limited pulses was 7ps with a peak power of 6mW. Low uncorrelated timing jitter below 1ps was found in cross correlation experiments. High-frequency operation of the lasers was eased by a ridge waveguide design that includes etching through the active layer.