Fiber scanners are portable and miniaturized laser scanning devices used for a wide range of applications, such as endoscopic probes for biomedical imaging. However, in order to achieve different resonant frequencies for 2D actuation, existing fiber scanners have complex actuation mechanisms and structures, resulting in being an obstacle for endoscopic imaging. By exploiting the intrinsic difference in bending stiffness of non-symmetrical fibers, we present the most simplified fiber scanner to date, containing only a single piezoelectric bimorph and a single non-symmetrical fiber with a 1D actuator for 2D laser scanning. 5-fps (frames per second) Lissajous scan is achieved with a scanning range of $>300\mathrm{\mu m}$ and a driving voltage of $\le 10{\mathit{V}}_{\mathrm{pp}}$. The ultra simplified structure of the fiber scanner enables a miniaturized optical probe with a diameter of 1.9 mm, and image quality comparable to that of commercial microscopes. Taking advantage of its ease of manufacture and low cost, the fiber scanner offers a transformative way forward for disposable endoscopic probes that avoid the risk of cross infection during endoscopic inspections.