"The fiber winding interferometric filter structure and its corresponding random laser output."

"The partially coherent light source with moderate introduction of incoherent modes combines high resolution with speckle suppression. However, the achievement of a balanced lasing mode and tunable output remains a critical challenge, influenced by mode interaction and gain competition. Here, a fiber winding interferometric filter was fabricated using a chemical etching method to suppress mode competition. The TiO\u2082 nanoparticles were then deposited on the etched region to introduce coherent feedback, which, in conjunction with the incoherent feedback from a single-mode fiber (SMF), formed a hybrid-feedback cavity. Compared to traditional partially coherent random laser (RL), the maximum proportion of the coherent mode was increased by a factor of 2.6. Moreover, the limitations of traditional RL systems, where coherent modes are suppressed and mode intensity fractions are inaccurate under high pump power, have been overcome. Our work provides a tunable partially coherent light source for dynamic scattering environments, such as geological exploration, biomedicine, and marine detection, while also offering key insights and technical solutions for hybrid feedback mechanisms and the balanced modes coexistence."