Zhengrong Tong

Temperature-Independent Rotational Angle Sensor Based on Fiber Bragg Grating

A novel temperature-insensitive fiber Bragg grating (FBG) rotational angle sensor is presented. The temperature-independent property of the sensor, as well as the adjustability of sensitivity and measurement range by means of altering the dimensions of the sensor, is analyzed both theoretically and experimentally. The experimental results demonstrate that a high sensitivity of 0.743 nm/deg over the range of the rotational angle from -21 to +21 is achieved.

Multiwavelength erbium-doped fiber laser based on graphene oxide

A multiwavelength erbium-doped fiber (EDF) laser based on graphene oxide (GO) has been proposed, to the best of our knowledge, for the first time, to generate an output of stable wavelengths. The structure mainly comprises a few layers of GO between two single-mode fibers incorporated into a capillary device and a Lyot comb filter. GO can show a good nonlinear optical effect, which is beneficial to suppress the mode competition caused by the EDF and stabilize the multiwavelength output. With assistance from the GO device, 11 stable simultaneous lasing signals with a power nonuniformity of about 1.5 dB are obtained. Wavelength spacing is about 0.42 nm and the linewidth of each wavelength is less than 0.07 nm.

Temporal Characteristics of a High Power Erbium-Doped Fiber Ring Laser

The temporal characteristics of a fiber ring laser are reported. The laser has a simple configuration, which contains an Erbium-doped fiber amplifier (EDFA), a polarization controller (PC) and a coupler. The EDFA has a high saturation power of 27dBm to provide the gain in the cavity. The PC is used to control the polarization state of light. A 99/1 coupler is used to extract the laser output. There is no filter in the cavity to confine the spectrum of the laser. The simple laser configuration can operate in different temporal modes with different pump power. In the self mode locking state, the repetition rate is equal to the inverse of the round trip time of the cavity. The repetition rate of the laser can be increased by increasing the pump power of the EDFA. This self mode locking phenomena is due to the homogeneous gain medium in the cavity, rather than the nonlinear effect in the cavity. The nonlinear effect can suppress the self mode locking phenomena by inserting a short length highly nonlinear fiber in the laser cavity.

Research on the sensing characteristic of blazed fiber Bragg grating

As novel passive optical components, fiber gratings have a comprehensive prospect in optical communication and sensing systems, due to their excellent optical properties. Blazed fiber Bragg grating, an important member of fiber gratings, because of its special structure, not only has all properties of fiber Bragg grating, but also has its own unique properties. With the fiber sensitivity enhanced and the technology of fabrication fiber grating improved, blazed fiber Bragg grating with an excellent character comes true, which have been used in the area of gain flatten, sensing system and wavelength demodulation. The sensing theory of blazed fiber Bragg grating is presented in the paper. Theoretical and Experimental research on its temperature sensing characteristic, strain sensing characteristic have been taken. The blazed fiber Bragg grating has the same temperature sensing and strain sensing characteristic as fiber Bragg grating. The temperature sensitivity experiments of the grating have been studied. By packaging fiber gratings with a special type of polymer, the experiments indicate that the temperature sensitivity to seven times.

Research of FBG multiplexing/demodulation on LPG

Long-period grating(LPG) which has a grating period of more than 100μm is a new kind of fiber gratting and its principle is that optical power is coupled from the forward transmission fundamental core mode to the forward transmission cladding modes and is attenuated after some distance. Transmission spectrum of LPG has a range close to linearity in both side of the peak. This range can be use as double edge filter on this property. Cascaded LPGs have special spectrum which is used as filters in multiple technology.