Provided are an optical coupler and an active optical module including the same. The optical coupler includes at least one first optical fiber, a second optical fiber, and a hollow optical block. The at least one first optical fiber transfers pump light. The second optical fiber includes a cladding with a facet enlarged from a first outer diameter to a second outer diameter, and passes the pump light which is transferred through the first optical fiber. The hollow optical block includes a through hole, an incident surface, and a coupling surface. The through hole passes the cladding with the first outer diameter. The incident surface is connected to the first optical fiber at a side end of the through hole. The coupling surface is joined to the facet of the second optical fiber at the other side end of the through hole facing the incident surface.