In this work, an Erbium doped ring fiber laser cavity based on in-line fiber optic interferometer (IFOI) for multiwavelength operation is proposed. To fabricate the modal filter small sections of thin-core fiber (TCF) and no-core fiber (NCF) were used. The TCF is a highly Erbium doped fiber that generated special characteristics such as: side mode suppression ratio of 43.10 dB, low threshold (75mA), minimal power instabilities (0.47dB) and lower wavelength drift (0.1nm). By controlling the bending of the fiber filter and adjusting the polarization stage is possible to obtain: single, dual and triple laser emission. The laser offers compactness and low-cost implementation.
We present a multi-wavelength ring fiber laser cavity based on modified loop fiber optic interferometer. Here, the interferometer is composed by three segments: two thin-core fiber (TCF) sections and one no-core fiber (NCF) section, these fibers are arranged as follows: TCF-NFC-TCF, then this structure is set into a fiber loop. Hence, by using a conventional ring laser cavity the proposed fiber optic loop is seed. Afterward, by controlling the modal fiber curvature and the ring cavity polarization state: single, dual and triple lasing modes can be achieved. The laser offers good power and wavelength stability, the maximal variations are 0.2 nm and 0.12 dB.