| With development of information technology, optical fiber communication system has been widely used, the high-speed coherent optical communication system will be the next target. Fiber bragg grating external cavity semiconductor laser (FBG-ECL) has narrowed linewidth, tunable wavelength, good frequency stability and many other advantages, making it the ideal light source for high-speed coherent optical communication system. In addition, FBG-ECL also has broad application prospects in spectral analysis, coherent detection, medical diagnosis.In this thesis, FBG-ECL is the research target. First, the background and development of semiconductor lasers is introduced, working principle, performance parameters and method of manufacture of the two part of FBG-ECL, semiconductor laser and fiber bragg grating, are introduced and analyzed. Second, using the rate equations of external cavity laser, optical feedback theory of equivalent cavity, get the reflectivity of equivalent external cavity, the linewidth and noise of the FBG-ECL is analyzed. Last, design and product the chip of the semiconductor laser, design and choose the fiber bragg grating, get the butterfly packaged external cavity laser. Within 25?250 mA drive current, laser has mono mode output and output power will be lOmW, side-mode suppression ratio more than 40dB, linewidth less than 100kHz. Design and built a tunable external optical feedback system, in which the optical feedback intensity can be adjusted. The linewidth of the laser is measured by delayed self-homodyne technique, and the changes of linewidth of the laser with different external optical feedback are analyzed. The experiments show that the linewidth of the laser decreases without change of relative intensity noise when the optical feedback increases in a scope. At different work temperature, the experiments have the same result, so this feedback system could be an effective way to narrow the linewidth of packaged FBG-ECL. |
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