title: Lensless intracavity focusing in a passively Q-switched all-fiber laser using the mode-field-area mismatch.
abstract: Intense lensless intracavity focusing in a saturable absorber Q-switched all-fiber laser resonator by use of loss arrangement and mode-field-area mismatch between the fibers is investigated for the first time. The intracavity power distribution was related to the locations and values of the cavity losses as the saturable absorption loss, the reflection loss of the output coupler, and the splicing loss between the gain fiber and the absorber fiber. With a mode-field-area mismatch and a reduced splicing loss with the gain fiber, a power density in the absorber fiber was achieved that was 11.9 times higher than that in the gain fiber.
authors: Lasers and Photonics Laboratory, Institute of Microelectronics, Department of Electrical Engineering, National Cheng Kung University, No. 1 University Rd., Tainan City, 70101, Taiwan. tzongyow@mail.ncku.edu.tw
authors: Tzong-Yow
authors: TY
authors: Tsai
authors: Zhi-Cheng
authors: ZC
authors: Lee
authors: Hong-Xi
authors: HX
authors: Tsao
authors: Shih-Ting
authors: ST
authors: Lin