Integrated tunable quantum-dot laser for optical coherence tomography in the 1.7 μm wavelength region

In this paper we present the design and characterization of a monolithically integrated tunable laser for optical coherence tomography in medicine. This laser is the first monolithic photonic integrated circuit containing quantum-dot amplifiers, phase modulators and passive components. We demonstrate electro-optical tuning capabilities over 60nm between 1685 and 1745nm, which is the largest tuning range demonstrated for an arrayed waveguide grating controlled tunable laser. Furthermore, it demonstrates that the activepassive integration technology designed for the 1550nm telecom wavelength region can also be used in the 1600-1800nm region. The tunable laser has a 0.11nm effective linewidth and an approximately 0.1mW output power. Scanning capabilities of the laser are demonstrated in a free space Michelson interferometer setup where the laser is scanned over the 60nm in 4000 steps with a 500Hz scan frequency. Switching between two wavelengths within this 60nm range is demonstrated to be possible within 500ns.