As Koji pointed out, I messed up the calibration.  However, fixing it doesn't change things that much.

From this calibration by Yuta, the Xarm ALS calibration is 54 deg / MHz, or 19.17 kHz / deg.  So, I multiply my data which is in these degree units by 19.17e3 to get Hz.  Then I use delta_f / f = delta_L / L to convert to meters.  f = c / lambda_green, and L = 37.5 meters. 

This only changes the calibration by about 10-15%.  It still looks like the ALS noise is well above the RIN level of the sqrtInv signal.