@article{SisLab2098,
          volume = {30},
          number = {6},
           month = {June},
          author = {Van Hoi Pham and Huy Bui and Thanh Son Pham and The Anh Nguyen and Thuy Van Nguyen and Huu Thang Le and Trung Ninh Bui and Van Phu Nguyen and Coisson Roberto},
           title = {Control of whispering-gallery-mode spectrum from
erbium-doped silica microsphere lasers},
         journal = {J. Opt. Soc. Am. B},
           pages = {1586--1589},
            year = {2013},
             url = {https://eprints.uet.vnu.edu.vn/eprints/id/eprint/2098/},
        abstract = {High-power whispering-gallery modes (WGMs) emitted from microcavity lasers have attracted attention for many
applications, such as optical signal processing, spectroscopy, optical sensors, and large-bandwidth optical com-
munications. In this paper, we present a simple approach for controlling the outputWGMs of erbium-doped silica
microsphere lasers. With the presented scheme, accurate adjustment of the coupling gap between the collection
fiber taper and the spherical surface allows us to select different single modes of the microsphere laser or different
multimode configurations (also functions of the waist diameter of taper and the Er-doped concentration). The
nonlinear frequency shift of the microsphere cavity as a function of intracavity power has also been studied.
The high intensity and high sidemode suppression ratio of the obtained singleWGMare suitable for spectroscopy,
optical sensors, and communications. {\copyright} 2013 Optical Society of America}
}