Research On Injection Locking Of Diode Lasers

The technology of diode laser has been developed rapidly in recent years and the performance continuously improved. Because of its small size, long life, low price, easy to operate, tunable wavelength and pumped by current, diode laser in recent years has been widely used in optical fiber communications, high-resolution laser spectroscopy, laser cooling and trapping, and other fields. However, in the experiment of atoms laser cooling and trapping, a high power, narrow linewidth and frequency-stabilized laser is required. The injection locking technique is an effective method to obtain such laser. In order to realize the experiment of laser cooling and trapping, we have set up a laser diode injection locking system and achieve a laser with single mode, narrow linewidth and 70mW power output.The injection locking method consisted of two diode lasers. A fraction of the output beam of the first laser called the master laser (ML) was injected into the second laser referred to as the slave laser (SL). The locking occurred within a certain frequency locking range determined by the injection level and the amplitude-phase coupling coefficient.In the thesis, firstly, we report the development history of diode laser and injection locking. Secondly, we describe the setup of our laser diode injection locking system. In our experiment, the output of an external cavity diode laser (ECDL), which is locked onto the D2 line of 87Rb, is injected into a common commercial 784nm laser diode to achieve the injection locking. This yields a 70mW single mode laser with line-width less than 1MHz, which is to be used in laser trapping of 87Rb atom. Furthermore, the influences of the parameters, including the seed light power, the injection current and the temperature, on the operating characteristics of the injection locked laser diode is investigated by measuring the signals of saturated absorption. The threshold over which the locking would be interrupted due to the variation of the current and the temperature is also derived, which leads to the optimized operating parameters of injection locking. Thirdly, we research that as the different of injection laser power, diode laser induced instability and appeared chaos in theory. Finally, next work is previewed.