Reconfigurable microfiber-coupled photonic crystal resonator.

We propose and demonstrate reconfigurable microfiber-coupled photonic crystal (PhC) lasers. In this generic configuration, the position of a PhC resonator can be defined (and redefined) repeatedly by simply relocating a curved microfiber along the linear PhC waveguide. In the proximity of the PhC waveguide in contact with the microfiber, the cutoff frequency (effective index) of the PhC waveguide becomes smaller (larger) than that of a bare PhC waveguide. Accordingly, when a curved microfiber is in contact with the PhC waveguide, a linear PhC resonator having Gaussian-shaped potential well is formed. Experimentally we confirm the formation of the reconfigurable resonator by observing laser operation slightly below three available band edges.