## 4 Discussion  
### Optical Amplifier Characterization Discussion  
In Figure 15, all four simulations agreed well with the measured data. The best fits were with the 26 and 55 cm fibers, except for the attenuation step between 66 mW and 226 mW of pump power. For these pump powers on the 55 cm fiber, it is believed there was additional attenuation than nominal, such as dust or other particles on the ND filter that were not fully accounted for when adjusting the attenuated measured signal. The 86 cm and 106 cm fibers did not appear to be matched as well, but this is also believed to be from an attenuation step. The 86 cm fiber had a change in attenuation at 191 mW of pump power and the 106 cm fiber had an attenuation change at a pump power of 208 mW, which both correspond to the steps in data. Initially, the fit parameter values in Table 5 were all similar; however, the 86 cm fiber and the 106 cm fiber fit much better by almost doubling \(C_{upcon}\) and increasing the connector losses by \(\sim\)25% each. This was believed to be caused by either differences in the manufacturing batch or connector polishing, since the 86 cm and the 106 cm fiber were purchased a few years after the 26 cm and 55 cm fibers. Additionally, it is possible that the model does not fully capture some losses that increase with fiber length and is thus negligible for the 55 cm and 26 cm fibers and not not negligible for 86 cm and 106 cm. One possibility is that the ASE spectrum may be too narrow or the steps may be too coarse to capture the losses. The ASE band simulated was 1520 to 1580 nm, since this is the optical band that can pass through the exit isolator and are included in the detector measurement.  
The model could be better evaluated if measurements at higher pump powers were taken. The reason for the 300 mW cap of pump power with a pump capable of delivering 500 mW of power is that the losses from the pump to the entrance of the erbium doped fiber were high (\(\sim\)40%). These losses were attributable to the addition of the pump pickoff measurements that were used to provide a higher certainty of the pump power emitted than the integrated monitor diode. The pump pickoff utilized HI106 FLEX fiber which has different optical properties than the SMF-28 fiber that was used throughout the rest of the fiber optics. It should be noted that the erbium doped fiber was not SMF-28 but is designed to be compatible with it. Splicing all connections, utilizing the same fiber (or compatible), and having a well-calibrated pump monitor diode would increase the pump power delivered to the erbium doped fiber without sacrificing knowledge of how much pump power is being emitted.  
As seen in the simulation results in Figure 16, the MOCT amplifier design is anticipated to be able to close all three optical links. Both the guard time and the pump power should be considered when tuning the transmitted peak power for an optical link. For instance, consider a LEO to LEO crosslink where M is 32 and the slot width is 400 ps. Utilizing 1.5 W of pump power requires \(\sim\)15 us guard time and the corresponding data rate is \(\sim\)333 kbps. Increasing the pump to 4 W requires a guard time of \(\sim\)2 us and the data rate for this higher pump power goes up to \(\sim\)2.48 Mbps. Depending on the mission situation, it may be worth the additional power consumption to achieve a higher data rate.