Study Of Magnetic Fluid Transmittance Properties In Optical Fiber By Applying Magnetic Field

Magnetic fluid, with magnetism and liquidity of liquid, is a kind of nanometer material. Under the effect of magnetic field, it can display peculiar transmittance characteristic of light. These light transmittance properties of magnetic fluid will probably be applied in the field of optical device and fiber optical sensors. Therefore, the study of the influence that magnetic field will make on light transmittance properties of magnetic fluid is very significant.Though the study of this field has been done a lot for many years, but its mechanism and laws also is not very clear, and the studies usually focused on the magnetic fluid in the sample box. This paper tries to study it from a new angle. The sample will be got by putting magnetic fluid in optical fibers. And then the light transmittance characteristics of magnetic fluid in optical fibers will be studied in this paper. The research content and result will conclude the following part:1The preparation of magnetic-fluid core optical fiber and the design of the external magnetic fieldAccording to the particular structure of optic fibers, in order to place magnetic fluid in optic fiber, a set of device was designed. According to the requirements, magnetic field device was designed too.2The research of the light transmittance characteristics of magnetic-fluid in optical fiber under well-distributed magnetic fieldPut the sampling into the environment of uniform magnetic field and discussed the influence of magnetic field intensity and magnetic field direction to the magnetic fluid in the optic fiber. At the same time, we also discussed the switch characteristic and time response of the magnetic fluid.3The research of the light transmittance characteristics of the magnetic fluid in the optic fiber under gradient magnetic fieldIn the condition of the gradient magnetic field, we have studied the light transmittance of the magnetic fluid and put forward a new theory model that density distribution of magnetic particle is gradient under the effect of gradient magnetic field. Based on that, we analyzed the theory. At the same time, we also discussed the time response and the phenomenon of hysteresis. The experiment results indict: Magnetic fluid in optical fiber obviously has the light transmittance modulation and switching characteristics under applied magnetic. The Light transmittance power of the magnetic fluid in the gradient field is much bigger than that in the uniform magnetic field, but the stabilization time is shorter. Analysis shows that the magnetic particles mainly form chains and agglomeration under uniform magnetic field, otherwise, they not only form chains and agglomeration but also appear to be a distribution of intensity gradient under gradient magnetic field. So the transmittance characteristic is different under different magnetic field. The research of the change of the magnetic fluid in the optic fiber under the extra magnetic field is hoped to be used in optical switch, optical modulator, optical attenuator, magnetic field sensor, current sensor and so on..