A fuel injector includes a nozzle having at least one first orifice provided therein. The at least one first orifice is adapted to selectively inject one of a fuel and an oxidant. An outer check is disposed movably within the nozzle. The outer check includes at least one second orifice provided therein. The at least one second orifice is adapted to selectively inject an other of the oxidant and the fuel. An inner check is disposed movably and concentrically within the outer chock. The at least one second orifice is adapted to align with respect to the at least one first orifice to selectively inject the fuel and the oxidant together through the at least one first orifice based on a position of each of the outer check and the inner check.