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In this paper, we present the first tunable extended cavity integrated passively mode-locked laser realized in an anticolliding design. The laser is realized as an InP-based photonic integrated circuit. A detailed study of the laser performance under various operating conditions is presented. The evolution of the radio-frequency (RF) spectrum and optical spectrum with the injection current to the optical amplifier is investigated. Tuning over 9 nm is achieved by injecting current in a distributed Bragg reflector section. We demonstrate that tuning of the optical spectrum toward shorter wavelengths, which increases absorption in the saturable absorber section, leads to an improvement of the mode-locked laser performance in terms of reduction of fundamental RF linewidth and reduction of the pulsewidths.

In this paper, measurements and analysis of the small-signal net modal gain of single-layer InAs/InP(100) quantum-dot (QD) optical amplifiers are presented. The amplifiers use only a single layer of InAs QDs on top of a thin InAs quantum well. The devices have been fabricated using a layer stack that is compatible with active-passive integration scheme, which makes further integration possible. The measurement results show sufficient optical gain in the amplifiers and can thus be used in applications such as lasers for long-wavelength optical coherence tomography and gas detection. The temperature dependence of the modal gain is also characterized. An existing rate-equation model was adapted and has been applied to analyze the measured gain spectra. The current injection efficiency has been introduced in the model to obtain a good fit with the measurement. It is found that only a small portion ( ~ 1.7%) of the injected carriers is actually captured by the QDs. The temperature dependence of several parameters describing the QDs is also discovered. The mechanisms causing the blue shift of peak gain as the current density increases and the temperature changes are analyzed and discussed in detail.

We present the calibration method and characterization of a monolithically integrated semiconductor optical pulse shaper. The photonic integrated circuit has been realized in an InP-based generic photonic foundry process. In this circuit, a 20-channel arrayed waveguide grating filter with 50-GHz channel spacing and 20 phase modulators and semiconductor optical amplifiers are combined on the InP chip. By calibrating the device, a mathematical description of the pulse shaper is obtained. The theoretical procedure for complete calibration of the device is presented, and the details of the experiments and measurement setups are given. We demonstrate that the frequency response of the pulse shaper can be calculated from the response of the individual channels in a reference state of the control signals and a separate mask function that describes the effect of a change in the control signals.