Optical microfiber-based ultrafast fiber lasers

Optical microfibers drawn from conventional fibers have attracted considerable interests and have found many novel applications. Here, we review recent advances in ultrafast fiber lasers based on optical microfibers. Starting with characteristics and fabrication of optical microfibers, which are closely related to ultrafast fiber lasers, we show that characteristics of large portion of evanescent field, tailorable dispersion, high optical nonlinearity, very low optical loss and full compatibility with conventional fibers are greatly beneficial to novel ultrafast fiber lasers. We then highlight recent works on ultrafast fiber lasers based on optical microfibers in terms of fast saturable absorbers made from optical microfiber-supported nanomaterials, dispersion management and high optical nonlinearity, as well as some other novel ultrafast fiber lasers. Finally, we briefly discuss future opportunities for optical microfiber-based ultrafast fiber lasers, such as high-order dispersion management, nonlinearity management and applications for sensing and measurement.