PROBLEM TO BE SOLVED: To provide a superluminescent diode capable of easily controlling an optical output and a spectral shape with high accuracy in a short period of time.SOLUTION: A light-emitting element 100 includes: an optical waveguide layer obtained by sequentially laminating a lower clad layer 112, an active layer 113 and an upper clad layer 114 on a base plate 111 provided with a lower electrode 110 from the base plate 111 side； an upper electrode 116 for injecting carrier into the active layer 113； and first and second end surfaces 101, 105 on which the optical waveguide layer is a light emission surface. The light-emitting element includes a first light reception part 104 for receiving a portion of the light power of an outgoing beam from the first end surface 101 and generating first light information, wherein the beam characteristic of the outgoing beam from the first end surface 101 is different from that of an outgoing beam from the second end surface 105, a second light reception part 107 for receiving a portion of the light power of the outgoing beam from the second end surface 105 and generating second light information, and a control part 120 for controlling a current injection amount to the upper electrode 116 on the basis of the first and second light information.SELECTED DRAWING: Figure 1
