Abstract: The present disclosure provides a waveguide integrated optical modulator, which is made of a bismuth film, an antimony film, or a tellurium film. A thickness of the bismuth film, the antimony film, or the tellurium film is between 10 nm and 200 nm, and the bismuth film, the antimony film, or the tellurium film is produced by physical vapor deposition method. The waveguide integrated optical modulator can directly add the symmetrical electrode on the surface of the bismuth film, the antimony film, or the tellurium film, and apply an external bias voltage of different amplitudes to the bismuth film, the antimony film, or the tellurium film by adjusting the power source. Thus, the waveguide integrated optical modulator can actively control the nonlinear optical characteristics of the saturable absorber by changing the magnitude of the external voltage, and further actively modulate the laser characteristics of the pulse.

Abstract: The present disclosure provides a waveguide integrated optical modulator, which is made of a bismuth film, an antimony film, or a tellurium film. A thickness of the bismuth film, the antimony film, or the tellurium film is between 10 nm and 200 nm, and the bismuth film, the antimony film, or the tellurium film is produced by physical vapor deposition method. The waveguide integrated optical modulator can directly add the symmetrical electrode on the surface of the bismuth film, the antimony film, or the tellurium film, and apply an external bias voltage of different amplitudes to the bismuth film, the antimony film, or the tellurium film by adjusting the power source. Thus, the waveguide integrated optical modulator can actively control the nonlinear optical characteristics of the saturable absorber by changing the magnitude of the external voltage, and further actively modulate the laser characteristics of the pulse.

Abstract: The present disclosure provides an apparatus and a method for measuring a concentration of pollutants in water. A passive Q-switched fiber laser outputs an evanescent wave to a to-be-tested water sample after emitting a Q-switched pulse laser signal and transmitting it via an evanescent field fiber, and based on an evanescent wave change caused by an absorption effect of the pollutants in the to-be-tested water sample to the evanescent wave and an output repetition frequency change of the passive Q-switched fiber laser due to the evanescent wave change, outputs an output repetition frequency result of the passive Q-switched fiber laser. The method is simple; and the apparatus based on the method is simple in structure and low in cost.

Abstract: The present disclosure provides an apparatus and a method for measuring a concentration of pollutants in water. A passive Q-switched fiber laser outputs an evanescent wave to a to-be-tested water sample after emitting a Q-switched pulse laser signal and transmitting it via an evanescent field fiber, and based on an evanescent wave change caused by an absorption effect of the pollutants in the to-be-tested water sample to the evanescent wave and an output repetition frequency change of the passive Q-switched fiber laser due to the evanescent wave change, outputs an output repetition frequency result of the passive Q-switched fiber laser. The method is simple; and the apparatus based on the method is simple in structure and low in cost.

Abstract: A two-dimensional semiconductor saturable absorber mirror comprises an optical fiber, a two-dimensional semiconductor thin film attached to an end surface of the optical fiber, and a gold film attached to the two-dimensional semiconductor thin film. A method for fabricating the two-dimensional semiconductor saturable absorber mirror comprises the following steps: cutting the optical fiber, putting the cut optical fiber and a two-dimensional semiconductor target into a vacuum chamber, ionizing a surface of two-dimensional semiconductor target to generate two-dimensional semiconductor plasma, depositing the two-dimensional semiconductor plasma on an exposed end surface of the optical fiber to form the two-dimensional semiconductor thin film, and by controlling deposition time and/or deposition temperature, ensuring the two-dimensional semiconductor thin film to be a desired thickness; and plating the gold film on the resulting two-dimensional semi-conductor thin film.