Optical fibers coated with various non-magnetized ferromagnetic materials and actuated by external magnetic fields were designed and characterized to demonstrate the feasibility for remote scanning. Cobalt, iron, nickel, and samarium-cobalt powders were used to enable the actuation. Silica optical fibers were coated with a mixture of 70% enamel paint and 30% various ferromagnetic materials. The static and dynamic measurements were preformed under the remote control of an electromagnet. Experiments with different ferromagnetic materials and different suspended fiber lengths of 3.2 cm, 4.2 cm, 5.2 cm, 6.2 cm, and 7.2 cm were performed to compare with theory. The static displacements, dynamic displacements and resonant frequencies of the actuation were measured.

A compact fiber optic scanner for biomedical applications such as optical coherent tomography has been designed, fabricated and tested. The scanner is designed as an in vivo device and composed of an optical fiber coated with nickelpowder loaded paint for external magnetic actuation. The compactness of the imaging device makes it suitable for applications where size, precision and low power consumption is critical. We have previously demonstrated the principles utilizing magnetic actuation for the fiber scanner coated with magnetic gel. This work focused on verification and optimization of the scanner operation. The magnetic properties of the nickel particle mixed with paint were characterized using an alternating gradient magnetometer. The optical scanner is externally actuated by an electromagnet and so it does not require a voltage or current supply in the probe itself. The displacements of the scanner were recorded using a position sensitive detector. The result showed a 0.8-mm displacement under the influence of a static magnetic field of 17.6 KA/m in a fiber with a moveable length of 4.2cm. Dynamic analysis showed a displacement of 0.83mm with an input current amplitude of 41mA and a magnetic field of 2.4 KA/m. The measurements are in good agreement with the theoretical lumped-element calculations. Finite-element analysis was performed and the results agree with the theoretical and experimental results. The static and dynamic displacements of the fiber optic scanner depend on the thickness and length of the magnetic coating. Thus, scanners for different displacements and operating frequencies can be designed by varying the coating thickness and length.

This paper presents the design, fabrication and testing of a fiber optic switch actuated electromagnetically. The ferromagnetic gel coated optical fiber is actuated using external electromagnetic fields. The ferromagnetic gel consists of ferromagnetic powders dispersed in epoxy. The fabrication utilizes a simple cost-effective coating setup. A direct fiberto-fiber alignment eliminates the need for complementary optical parts and the displacement of fiber switches the laser coupling. The magnetic characteristics of magnetized ferromagnetic materials are performed using alternating gradient magnetometer and the magnetic hysteresis curves are measured for different ferromagnetic materials including iron, cobalt, and nickel. Optical fiber switches with various fiber lengths are actuated and their static and dynamic responses for the same volume of ferromagnetic gel are summarized. The highest displacement is 1.345 mm with an input current of 260mA. In this paper, the performance of fiber switches with various coating materials is presented.