This present invention proposes new methods of designing single-use endoscopes with built-in optical fibers and operating fixtures. As compared to conventional endoscopes, a separate lumen is reserved for integrating a laser fiber along the insertion tube of the proposed endoscope, and an optical fiber placement device (OFPD) is correspondingly added in the endoscope handle for controlling the movement of the laser fiber. By sliding the slider or dialing the wheel of OFPD, a surgeon can conveniently control movement of the laser fiber. By pressing a retractable control stick in the OFPD, the surgeon can either push the laser fiber out from the endoscopes distal-end or pull back the laser fiber, further unlocking or locking the power switch of the laser fiber to avoid mis-operations. All these above operations can be performed by the surgeons one-hand, including the routine deflections and rotations of the endoscope. Four implementations of the OFPD are introduced in this invention. In addition, an ultra-small optical fiber based pressure sensor can be added at the distal end of the endoscope upon applications.