Optical modulator having wide bandwidth based on Fabry-Perot resonant reflection is disclosed. The optical modulator includes: a bottom Distributed Bragg Reflector (DBR) layer; a top DBR layer including at least one layer, and a modified layer; and an active layer disposed between bottom and top DBR layers, wherein the at least one layer includes at least one pair of a first refractive index layer having a first refractive index and a second refractive index layer having a second refractive index, the modified layer includes at least one pair of a third refractive index layer having a third refractive index and a fourth refractive index layer having a fourth refractive index, the third and the fourth refractive indexes being different, and at least one of the third and the fourth refractive index layers has a second optical thickness that is not λ/4 or that is not an odd multiple thereof.