The reflection and transmission characteristics of a high-birefringence fiber loop mirror (HiBi-FLM), which is composed of a standard fiber coupler and one-section or multisection high-birefringence fibers (HBFs), are analyzed and discussed in detail. Theoretical reflectivity and transmissivity expressions for HiBi-FLMs with one-, two-, and three-section HBFs were obtained. The procedure for calculating reflectivity and transmissivity for HiBi-FLMs with n-section HBFs is given. Experimental results have verified the theoretical model. The basic characteristics of the one-section HiBi-FLM when strain and high temperature are applied to HBFs were analyzed and investigated theoretically and experimentally. The experimental results are in good agreement with the theoretical analysis. Furthermore, a strain– temperature sensor that makes use of those characteristics, which is new for applications of HiBi-FLMs, has been proposed and demonstrated.

A novel and simple technique, based on nonlinear polarization rotation (NPR) effect, to generate stable multiwavelength oscillations in an erbium-doped fiber laser is proposed and successfully demonstrated. The NPR effect effectively induced intensity- and wavelength-dependent loss to alleviate mode competition caused by homogeneous gain broadening in erbium-doped fibers. Up to 28-wavelength lasing operation with wavelength spacing of 0.8 nm has been achieved. The outputs had uniform power distributions, and the power fluctuation in each wavelength is smaller than 0.2 dB within a period of an hour.

In this paper, the pressure response of fiber Bragg gratings in grapefruit microstructured fibers was experimentally investigated and theoretically analyzed with full-vector finite element method. The theoretical calculation agrees well with the experimental results. The pressure changes the refractive index and induces axial strain of the fiber. The radial pressure induces positive strain, but axial pressure induces negative strain. The negative strain dominates. The existence of large air holes make grapefruit microstructured fibers experience larger negative strain than standard single-mode fiber, therefore fiber Bragg gratings in grapefruit microstructured fibers have larger pressure sensitivity than that in SMF.

A microwave photonic filter using a simple and novel multiwavelength erbium-doped fiber laser (EDFL) is proposed. The filter was experimentally demonstrated featuring tunability and reconfigurability by adjustment of the output from the EDFL. The experimental results show excellent agreement with the numerical simulations.

In this letter, a simple, switchable dual-wavelength erbium-doped fiber laser operating in L-band is successfully proposed and demonstrated. The two wavelengths are specified by a Bragg grating formed in multimode fiber and the wavelength separation is 1.7 nm. The multimode section including the multimode fiber grating selects not only the lasing wavelengths but also the polarization states of the lasing lines. Stable dual-wavelength operation can be achieved due to the spatial mode beating effect induced by a single-mode/multimode/single-mode fiber combination structure. By simple adjustment of a polarization controller, the proposed laser can operate in stable dual-wavelength or switch between two wavelengths, all at room temperature.