A linewidth formula for semiconductor-optical fiber ring lasers

The authors derive a formula of linewidth for a semiconductor-optical-fiber ring laser by using coupled rate equations for the active and passive cavity. It is shown that the linewidth is not only the function of the two-cavity length ratio and time delay in fiber, but also the function of light intensity ratio of the two cavities and the phase shift introduced by junctions between the gain medium and the optical fiber.<
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