After found a half waveplate in TAMA(it is a square one as in attached Fig.1), I used it to rotate the polarization of the output of FI.

After increasing laser power around 300mW,

     I checked the power before and after FI(see Fig.2 and Fig.3). The ratio is 90.55%(=280.8mW(detect after FI)/310.1mW(detect after the first lens)).

     The light comeing from the side of FI is really not a point. So it is very diffcult to detect it. Roughtly there is 7mW coming out from output side port, 3mW from input side port.

     I checked the p-polarization portion is 113.4uW, s-polarization portion is 235mW.(The total power sending to PBS is 245.9mW, this means we lose a lot of light by half waveplate and focal lens)

The maximun power we can reach for our laser is around 600mW.