Donor incorporation properties in an n-type modulation-doped beam-expander-integrated laser fabricated by shadow-mask growth

We investigated the donor incorporation properties in the beam expander (BEX) region of an n-type modulation doped (MD) MQW grown by both shadow mask growth (SMG) and selective area growth (SAG) from the viewpoint of the optical loss. As a result, we confirm that the donor concentration in the BEX region can be reduced for SMG, which is promising for decreasing the optical loss in the BEX region with keeping the MD effect in the gain region.