Performance characterization of chirped return-to-zero modulation format using an accurate receiver model

We derive an explicit relationship between the Q factor and the optical signal-to-noise ratio in optical fiber transmission systems for an arbitrary pulse shape using an accurate receiver model under the assumption that the noise is unpolarized. We also define the enhancement factor and two other parameters that explicitly quantify the relative performance of different modulation formats. We use this method to compare the performance of the chirped return-to-zero, return-to-zero, and nonreturn-to-zero modulation formats with a finite extinction ratio. The method that we propose can also be used as a tool for the design and optimization of optical receivers.