Study On The Controllable Slow And Fast Light In Optical Fiber And Its Application

The physics of the phenomenon of light propagation in medium with reduced oraccelerated group velocity is defined as slow and fast light. Due to the features of compactsize, room temperature operation and compatibility with present communication systems,slow and fast light in fiber have some important applications in all optical communication,optical sensor and enhancement of nonlinear effect, etc. The techniques of tunable slow andfast light have been widely studied. We have studied the slow and fast light in fiber. In thispaper we are focusing on the techniques based on stimulated Brillouin scattering (SBS) andcoherent population oscillation (CPO) effect in fiber. Based on this research, we realize a newtype of refractive index (RI) fiber sensing application using Brillouin fast light. The maincontents are as follows:1. Controllable slow and fast light in highly-doped erbium-doped fiber is studied. Basedon self-developed high gain erbium-ytterbium co-doped single-mode phosphate glass fiber,ultraslow propagation and superluminal propagation with group velocity values from8.4to14.7m/s are observed in a3.86cm long Er3+/Yb3+co-doped single-mode phosphate glassfiber. A slow/fast light device with a sealed size of130mm×30mm×3mm has beendemonstrated. The dependence of pump power, modulation frequency, and wavelength on theslow/fast light effect in this fiber is investigated in detail. The application of linewidthmeasurements of narrow linewidth laser based on slow/fast light effect is explored inexperiments.2. Fast light in fiber based on SBS is analyzed and demonstrated experimentally.Controllable self-induced SBS fast-light is realized in an optical fiber ring. The influence ofdifferent Brillouin gain medium on the fast light is investigated in detail. When using a10mlong HI1060FLEX single-mode fiber as Brillouin gain medium in the fiber ring, fast lightwith fractional advancement of0.7is achieved. A section of microfiber is inserted into theBrillouin fiber ring, and fast light with fractional advancement of0.66is achieved.3. A new type of RI sensor based on Brillouin fast light is proposed and demonstratedexperimentally. The RI sensor is invented by combining the evanescent-field scatteringsensing mechanism with the Brillouin fast light scheme. The RI of solution is achieved bymeasuring the signal advancement of SBS fast light. Within the RI range of1.436to1.449,the signal advancement decreases with the RI in the case the pump power is500mW. Thepotential measurement accuracy of the Brillouin-fast-light-based RI sensor is found to be on the order of Δn~2.510-6.