An optical sensing system comprising: a light output part configured to emit a first light to an object; and a sensing part configured to sense a second light reflected from the object, wherein the sensing part comprises: a photodetector; an active optical device disposed on an optical path between the photodetector and the object; a lens system, having positive refractive power, disposed on the optical path between the active optical device and the object, wherein the light output part comprises: a light source generating the first light; and a beam steering device configured to two-dimensionally steer the first light; wherein the first light is incident on the object along a first optical path, wherein the second light is reflected from the object along a second optical path different from the first optical path, wherein the lens system is configured to direct the second light transmitted therethrough to different regions of the active optical device depending on the location and direction that the second light is incident on the lens system, wherein the active optical device is configured to control an orientation of the second light transmitted therethrough and comprises a refractive-index change layer having a refractive index which is changeable by application of electrical signal, wherein the refractive-index change layer is divided into a plurality of unit regions, and wherein refractive indexes of the plurality of unit regions are individually controlled. a light output part configured to emit a first light to an object; and a sensing part configured to sense a second light reflected from the object, wherein the sensing part comprises: a photodetector; an active optical device disposed on an optical path between the photodetector and the object; a lens system, having positive refractive power, disposed on the optical path between the active optical device and the object, wherein the light output part comprises: a light source generating the first light; and a beam steering device configured to two-dimensionally steer the first light; wherein the first light is incident on the object along a first optical path, wherein the second light is reflected from the object along a second optical path different from the first optical path, wherein the lens system is configured to direct the second light transmitted therethrough to different regions of the active optical device depending on the location and direction that the second light is incident on the lens system, wherein the active optical device is configured to control an orientation of the second light transmitted therethrough and comprises a refractive-index change layer having a refractive index which is changeable by application of electrical signal, wherein the refractive-index change layer is divided into a plurality of unit regions, and wherein refractive indexes of the plurality of unit regions are individually controlled. a photodetector; an active optical device disposed on an optical path between the photodetector and the object; a lens system, having positive refractive power, disposed on the optical path between the active optical device and the object, wherein the light output part comprises: a light source generating the first light; and a beam steering device configured to two-dimensionally steer the first light; wherein the first light is incident on the object along a first optical path, wherein the second light is reflected from the object along a second optical path different from the first optical path, wherein the lens system is configured to direct the second light transmitted therethrough to different regions of the active optical device depending on the location and direction that the second light is incident on the lens system, wherein the active optical device is configured to control an orientation of the second light transmitted therethrough and comprises a refractive-index change layer having a refractive index which is changeable by application of electrical signal, wherein the refractive-index change layer is divided into a plurality of unit regions, and wherein refractive indexes of the plurality of unit regions are individually controlled. a light source generating the first light; and a beam steering device configured to two-dimensionally steer the first light; wherein the first light is incident on the object along a first optical path, wherein the second light is reflected from the object along a second optical path different from the first optical path, wherein the lens system is configured to direct the second light transmitted therethrough to different regions of the active optical device depending on the location and direction that the second light is incident on the lens system, wherein the active optical device is configured to control an orientation of the second light transmitted therethrough and comprises a refractive-index change layer having a refractive index which is changeable by application of electrical signal, wherein the refractive-index change layer is divided into a plurality of unit regions, and wherein refractive indexes of the plurality of unit regions are individually controlled.