Various embodiments of the present invention are related to microresonator systems that can be used as a laser, a modulator, and a photodetector and to methods for fabricating the microresonator systems. In one embodiment, a microresonator system (100) comprises a substrate (106) having a top surface layer (104), at least one waveguide (114,116) embedded within the substrate (106), and a microdisk (102) having a top layer (118), an intermediate layer (122), a bottom layer (120), current isolation region (128), and a peripheral annular region (124,126). The bottom layer (120) of the microdisk (102) is in electrical communication with the top surface layer (104) of the substrate (106) and is positioned so that at least a portion of the peripheral annular region (124,126) is located above the at least one waveguide (114,116). The current isolation region (128) is configured to occupy at least a portion of a central region of the microdisk and has a relatively lower refractive index and relatively larger bandgap than the peripheral annular region.