Single mode EDF fiber laser using an ultra-narrow bandwidth tunable optical filter

摘要

span style="mso-fareast-font-family: Calibri" lang="EN-GB"Single longitudinal mode (SLM) erbium-doped fiber (EDF) laser operation using a commercialized ultra-narrow bandwidth optical filter has been studied. A two-meter long EDF with an absorption coefficient of 24??dBmsupspan style="font-family:Symbol;mso-ascii-font-family:" times="" new="" roman";="" mso-fareast-font-family:calibri;mso-hansi-font-family:"times="" mso-char-type:symbol;mso-symbol-font-family:symbol"="" lang="EN-GB"-/span/supsupspan style="mso-fareast-font-family:Calibri" lang="EN-GB"1 /span/supspan style="mso-fareast-font-family:Calibri" lang="EN-GB"at the pump wavelength is used as gain medium. The ultra-narrow tunable filter is used for selection of a single longitudinal mode from the available spectrum of multiple modes, which originally exists in the FBG's reflection spectrum. Our approach provides a relatively simple and direct method for the realization of SLM operation. A high-resolution optical spectral analyzer with a resolution of 0.16 pm, is used to observe the output spectrum. To verify the SLM operation, the delayed self-heterodyne method is used, giving a measured laser linewidth of 61.5 kHz. /span/span