Studies of Noise in Semiconductor Laser Arrays
Final rept. Feb 1989-Feb 1990
DAYTON UNIV OH GRADUATE SCHOOL OF ENGINEERING AND RESEARCH
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Measurements were made of noise in laser arrays, both commercial gain-guided and experimental 10 element index-guided. Relative Intensity Noise RIN was found to be comparable to single element gain guided arrays, with approximately 15dB more noise than from a distributed feedback DFB laser. Comparable results for gain-guided and index-guided lasers, with supporting theoretical studies, indicate that mode competition is probably the source of the increased noise. Because the arrays produce more power, the increased noise does not necessarily degrade the signal-to-noise ratio. The results of this study indicate that if the system is operating in the receiver-noise-limited regime 0.1 milliwatts of detected optical power, use of an array will increase the overall signal-to-noise ratio. It was also shown that a reduction in laser noise can be achieved by low frequency modulation. For example, modulation at 10 MHz resulted in a decrease in noise by 5 to 10 dB at 100 MHz.
- Lasers and Masers
- Solid State Physics