Marc and Yuhang

On Monday, we found CC PLL couldn't be locked. We checked the RF signals, LO signals, locking loop set-up and correction signals.

LO signal is about -2dBm. Locking loop set-up was reloaded. Correction signal seems to be saturated. In the end, we found the RF signal was very small.

Although this may be related with just alignment, we decide to replace fiber since I remember there is a damage of CC PLL fiber (see fig 1).

The new fiber is fixed on top of AA breadboard, which makes it easier to be checked in the future. (see fig 2)

The RF signal reaches PLL lock loop is about -8.5dBm with new fiber and amplifier. (see fig 3)

The monitor channel shows -33dBm on the lower spectrum amplifier (see fig 4). Note that the fiber PD used for monitor is battery powered, which seems to be able to provide only RF signal.