Provided herein is an optical module including an optical bench having a first step with a first depth and a second step with a second depth that is smaller than the first depth; a silicon carrier disposed above the first step, and where at least one semiconductor chip is installed; an AWG chip (Arrayed Waveguide Grating chip) secured to the second step, extends up to the first step, and is chip-to-chip bonded with the silicon carrier above the first step; a lens disposed on an upper surface of the optical bench where the first step and the second step are not formed; and a metal package surrounding the optical bench, silicon carrier, AWG chip and lens, wherein at one side of the metal package, a double slit that includes an upper slit and a lower slit are formed, a DC FPCB (Direct Current FPCB) extends from outside towards inside the metal package through the upper slit and is secured to a support formed on an inner surface of the upper slit, and an RF FPCB (Radio Frequency FPCB) extends from outside towards inside the metal package through the lower slit and is secured to an upper portion of the silicon carrier, and the upper slit and the lower slit of the double slit being sealed by an elastic epoxy.