[Tomoyuki]
Thanks for the measurements.

The transimpedance gain in AC is 4-times higher than DC gain in the newport  photodetector (see attached file: pdgain.png).
So the figures which Nogai-kun made were rivised (attached pdfs).   

[Uehara]
I miscalculated AM/ DC. AC gain is 4times-bigger than DC gain. Then AC voltage * 0.25 should be compared to DC voltage. (I miscalcurated like (AC voltage*4)/(DC Voltage) )
Attached is revised figures and data. AC voltages mean peak-topeak voltages in these figures, so the voltage should be divided by 2 for usual amplitude.

[Tomoyuki]
For this measurement, we used 1611, not 1811 newport photodetector. However, the sensitivity of 1611 is same as 1811.