OPTICAL TRANSMISSION MODULE

PROBLEM TO BE SOLVED: To provide an optical transmission module capable of further reducing noise.SOLUTION: An optical transmission module comprises a first semiconductor layer provided with a first electrode, an active layer formed in a stripe shape on the first semiconductor layer, and a second semiconductor layer formed in the stripe shape on the active layer, provided with a second electrode, and including a diffraction grating provided along an extension direction of the active layer. The active layer includes a first portion extending at a first stripe width from one end surface, a second portion extending at a second stripe width smaller than the first stripe width from the side opposite to the one end surface, and a connection portion having a taper shape in which the stripe width changes and connecting the first portion and the second portion. In a plan view, the diffraction grating overlaps with the first portion, and does not overlap with the second portion.SELECTED DRAWING: Figure 1 【課題】ノイズをより低減した光送信モジュールを提供する。【解決手段】光送信モジュールは、第１電極が設けられた第１半導体層と、前記第１半導体層の上に、ストライプ状に形成された活性層と、前記活性層の上にストライプ状に形成され、第２電極が設けられ、前記活性層の延伸方向に沿って設けられた回折格子を含む第２半導体層と、を有し、前記活性層は、一方の端面から第１のストライプ幅で延伸する第１部分と、前記一方の端面の反対側から前記第１のストライプ幅よりも小さい第２のストライプ幅で延伸する第２部分と、ストライプ幅が変化して前記第１部分と前記第２部分を接続する接続部分と、を含み、前記回折格子は、平面視において、前記第１部分と重畳し、前記第２部分と重畳しない。【選択図】図１