The beam shape reflected by the PD was measured.
The measurement was done 5 cm and 15 cm far from the PD at 15 deg, 45 deg, and 60 deg in incident angle.
(Please note that only at 15 deg, the measurement was done at 5 cm because of the space constraint.)
The results are shown in Figs. 1 and 2 and Tabs. 1 and 2.
When Figs. 1 and 2 are observed, the beam shape reflected by the PD looks still gaussian.
In the simulation, the beam size is estimated as, at 5 cm, 403 um in x-direction and 391 um in y-direction and, at 15 cm, 792 um in x-direction and 766 um in y-direction, respectively.
When Tabs. 1 and 2 are observed, the measured beam size looks not so different from the simulated one.
Tab. 1 Beam size in x-direction
Tab. 2 Beam size in y-direciton