| In this work a study on the optical noise present in the light generated by semiconductor lasers is presented. The mode partition noise and its conversion into intensity noise when the light generated by a multimode laser diode is passed through unbalanced interferometers are investigated. As a result of the effects observed, the idea of noise interferometry is introduced. Also an optical white noise source is built, based on the noise interferometer. This optical noise source is demonstrated to achieve the frequency response of a photodetector. Two systems of stabilization of the mode partition noise level are proposed and demonstrated. Techniques for minimizing the optical noise in fiber optic sensors are discussed. Techniques of noise suppression are demonstrated in a passive in-line current sensor. A technique of optical intensity noise cancellation in a fiber-optic gyroscope is proposed and demonstrated. Finally a fiber-optic thermometer is designed and built, motivated by the lack of a good and cheap similar sensor in the market. |
