A light-emitting element includes a light-emitting region which is made from a stacked structure configured from a first compound semiconductor layer, an active layer, and a second compound semiconductor layer, and a light propagation region which is made from the stacked structure, extends from the light-emitting region, and has a light-emitting end surface. The drive system may have an engine, a pump driven by the engine to pressurize fluid, a motor connected to the pump via an inlet passage and an outlet passage, and a traction device driven by the motor. The tensioner assembly of the present invention includes a cylinder, a stop tube disposed with the cylinder, and a ram slidably engaged within the stop tube.