Research On Multiwavelength Brillouin-Erbium Fiber Laser And Its Application

Mutiwavelength Brillouin-erbium fiber laser (MBEFL) combines the Brillouin nonlinear gain and the erbium-doped fiber linear gain. It has the merits of high conversion efficiency, narrow linewidth, low threshold, high optical signal-to-noise ratio and constant wavelength spacing. It has the potential applications in all-optical communication and fiber-optic sensor. With the dramatically increasing demand for information capacity, the high-speed, large-capacity and long-distance optical communication are the trends of development in the next generation all-optical network. The dense wave division multiplexing (DWDM) technology is an effective avenue to tackle with the limited frequency of optical communication. This technology needs the channel spacing should meet the ITU-T frequency grid (such as 10GHz,25GHz,50GHz and etc.). So the MBEFL with different channel spacing will be the ideal optical communication light source in the future. In addition, MBEFL can be applied to microwave photonics (such as photonic generation of microwave signal, and microwave photonic filter) to overcome the "electronic bottleneck" of all-optical communication or/and wireless optical communication. Also, Brillouin optical fiber sensing technology takes the advantage of measuring temperaute and strain simultaneously, and can be applied to large bridges, tunnels, dams, railways, ships and warships, aerospace, electric power and etc. Brillouin-erbium fiber laser can stably generate high-order Brillouin signal at room temperature. Owing to high-order Brillouin signal has high sensitivity response to temperature and strain, high temperature of strain sensitivity can be achieved. So, intensively studying multiwavelength Brillouin-erbium fiber laser is not only has academic value, but also has important social significance.The main works are as follows:1. We have investigated the method of expanding the wavelength spacing of multiwavelength Brillouin-erbium fiber laser. A method of expanding the wavelength spacing and getting a multiple Brillouin frequency shift spaced multiwavelength fiber laser have been proposed by nesting two low-order Brillouin frequency shifter with each other. We have experimentally demonstrated multiwavelength Brillouin-erbium fiber lasers (MBEFLs) with triple-spacing and with quadruple-spacing. The triple-spaced and the quadruple-spaced multiwavelength Brillouin-erbium fiber lasers can operate stably in room temperature. The two MBEFLs own tunable output wavelength range and high optical signal-to-noise ratio. The triple-spaced MBEFL can be tuned within more than 30nm range by inseting a tunable bandpass filter in the caivity. The quadruple-spaced MBEFL have four stably output channels and the wavelength spacing is 0.353nm. The total power of output channels is about 4.2dBm, the power fluctuation is within±0.03dB.2. A microwave photonic filter based on self-seeded multiwavelength Brillouin-erbium fiber laser has been proposed and experimentally demonstrated. The filter frequency response holds a single passband feature. The filter frequency and the 3dB bandwidth of the filter can be tuned by adjusting the output spectra of the fiber laser. The filter frequency is tuned around the range of 5.76GHz-5.96GHz and the 3dB bandwidth is tuned around 120MHz-160MHz under a 100km long delay and dispersion fiber.3. Based on the beating demodulation technology, we propose a δ-type multiwavelength Brillouin-erbium fiber laser based temperature sensor. This sensor uses the mechanism that the high order Brillouin signal is dependant on temperature and strain with high sensitivity response. The proposed fiber laser sensor can realize temperature or strain sensor with high sensitivity. We have experimentally studied the temperature response of each high order Brillouin signal. The 12nd-order Brillouin signal holds the temperature sensitivity coefficient with 13.08MHz/℃.