[Yamamoto, Ushiba]

We found the source of the TEMP BIAS jump of PLLX/Y observed yesterday.

Figure 1 shows the PLL guardian state and temperature feedback signals for PLL X/Y and main laser durng recovery work of PLL X/Y yesterday.
When lock loss happened (left T cursor), temperature feedback to the main laser was cleared by guardian (IMC guardian has a function to clear temperature feedback if the value is greater than 0.1 at DOWN state).
Due to this feedback clear, the main IR laser frequency is changed very quickly: that results in changing the good TEMP BIAS of PLL X/Y.

In terms of long-term stability, it is better to manage it at some point but I leave it as it is at this moment.