Development of integrated microphotonics is widely recognized as the critical step for continuation of the optical revolution. Given the advanced processing technology and infrastructure, Si would be the ideal platform for development of integrated microphotonics, except for its optical inactivity due to its indirect bandgap. Strong optical activity can be obtained, however, from nanocrystal Si (nc-Si), and recent theoretical and experimental results suggest that the surface impurities of nc-Si luminescence play a critical role in determining the nc-Si luminescence. In this presentation, it will be shown that by intentionally introducing optical impurities, it is possible to control and enhance the nc-Si luminescence. Particular attention will be paid to the use of Er3+ as an optical dopant in the 1.54 mum range, and the control over the material structure and the nc-Si / Er interaction that need to be obtained in order to obtain efficient Er3+ luminescence. The use of such Er-doped nc-Si in fabricating Si microphotonic components will be demonstrated, and their potential for applications discussed. Finally, the use of carbon as another optical co-dopant to obtain luminescence in the visible range will be demonstrated.