A heat dissipation system for an optical module, comprising a circuit card on which at least one optical module is mounted, wherein the optical module comprises a housing and a laser disposed inside the housing ; a first heat dissipation apparatus is fixedly disposed on the circuit card; a planar heat dissipation window provided in an area that is above the laser and on the housing of the optical module; and the first heat dissipation apparatus is configured to perform heat dissipation on the heat dissipation window ; wherein the heat dissipation window is a heat sink fin in a cross structure, wherein the heat sink fin comprises multiple first toothed bars disposed at intervals in a first direction along the window plane and multiple second toothed bars disposed at intervals in a second direction along the window plane, where the second direction is perpendicular to the first direction; and the second toothed bars are located on surfaces of the first toothed bars , and the second toothed bars and the first toothed bars are disposed in a cross manner, wherein the multiple first toothed bars are disposed parallel to each other; and the multiple second toothed bars are disposed parallel to each other, whereby discharge paths are formed by gaps between the first toothed bars and the second toothed bars , wherein the first heat dissipation apparatus is a piezoelectric film fan, wherein the piezoelectric film fan comprises a hollow body , a film , and a piezoelectric plate , and the piezoelectric plate and the film are fixedly connected to form a piezoelectric structure; and the piezoelectric structure is disposed inside a hollow cavity of the body, and a gap exists between the piezoelectric structure and an inner wall of the body; and a first opening is provided on a surface on a side, corresponding to the piezoelectric plate , of the body; a nozzle is provided on a surface, opposite to the first opening , of the body, and the nozzle faces to the heat dissipation window ; and the piezoelectric plate is configured to be electrically connected to an alternating current. wherein the heat dissipation window is a heat sink fin in a cross structure, wherein the heat sink fin comprises multiple first toothed bars disposed at intervals in a first direction along the window plane and multiple second toothed bars disposed at intervals in a second direction along the window plane, where the second direction is perpendicular to the first direction; and the second toothed bars are located on surfaces of the first toothed bars , and the second toothed bars and the first toothed bars are disposed in a cross manner, wherein the multiple first toothed bars are disposed parallel to each other; and the multiple second toothed bars are disposed parallel to each other, whereby discharge paths are formed by gaps between the first toothed bars and the second toothed bars , wherein the first heat dissipation apparatus is a piezoelectric film fan, wherein the piezoelectric film fan comprises a hollow body , a film , and a piezoelectric plate , and the piezoelectric plate and the film are fixedly connected to form a piezoelectric structure; and the piezoelectric structure is disposed inside a hollow cavity of the body, and a gap exists between the piezoelectric structure and an inner wall of the body; and a first opening is provided on a surface on a side, corresponding to the piezoelectric plate , of the body; a nozzle is provided on a surface, opposite to the first opening , of the body, and the nozzle faces to the heat dissipation window ; and the piezoelectric plate is configured to be electrically connected to an alternating current. <EOS>