4 Numerical Capacity Results

All numerical evaluations were carried out on a 333MHz Pentium II using programs written in C and Perl. We used parameters from a 1064nm pulsed Q-switched Nd:YAG laser having slot width $T_s=31.25$ ns, required dead time $T_d = 432000$ ns, and modulation extinction ratio $\alpha_{er} = 10^6$. This laser was chosen based on its proposed use for X2000 2nd delivery [15]. The EG&G SLiK APD has the following parameters: $k_{\mbox{\small\em eff}}=0.007$, $T= 300^\circ$K, $R= 179700\Omega$, $B= {1 \over 2T_s}$ Hz., $I_b= 4\times 10^{-14}$ Amp., $I_s= 2\times 10^{-9}$ Amp., and $\eta= 38\%$. See Appendix A for a description of these parameters, or [4] for a more detailed explanation. All numerical results reported in the paper used an optimized APD gain. We discuss this optimization in Section 4.4; the optimal gain varied from 50 to 200, depending on the background level.