Due to the air humidity, the compressor grating absorbed some dust, this finally decrease the reflection efficiency. We replaced the old grating with the brand new one ordered from Spectra-physics. The measured power before compressor is about 500mW, after the compressor, the power is 300mW, which is bigger than 260mW using the old grating.
The power was decreased to 250mW when I added the 1.02ms delay for diode pump laser. After the delay time adjusted accurately, the power recovered to 300mW. The new delay time is 1020.2us.