Fig. 1: Principle of passive Q-switching and the intergated Q-switched laser.
From: Silicon photonics-based high-energy passively Q-switched laser
a, The principle of passive Q-switching. b, A compact integrated LMA pulsed laser. WDM, wavelength division multiplexer; NLI-SA, nonlinear Michelson interferometer-based saturable absorber; H1 and H2, high- and low-power heater arms. The pump is coupled into the gain section through a WDM. Within the green box region, the LMA sections are over the straight SiN waveguides, which are connected with each other through adiabatic tapers and tight bends. The NLI-SA splits the signal into two arms through a directional coupler and back-reflects via loop mirrors. Inset, the LMA waveguide cross-section along with the signal mode profiles in an LMA gain region and a bend. c, An optical image of the chip containing the device placed on top of a 50 cent Euro coin. Owing to the large aspect ratio of the device, for clarity microscope images were taken at different regions (dashed lines connecting these images are simply guides to the eye).
