An optical coupler module (2; 2a; 2b; 3) for converting and transmitting an electrical signal or an optical signal, the optical coupler module (2; 2a; 2b; 3) configured to be pluggably coupled to an optical transmission element (60; 63; 66; 80; 90) and the optical coupler module (2; 2a; 2b; 3) characterized in that the optical coupler module (2; 2a; 2b; 3) comprises: a semiconductor substrate (20; 30) made of silicon and having a first surface (201; 301) and a second surface (202; 302) opposite to the first surface (201; 301); a first film (21; 21a; 31) and a second film (22; 32) formed on the first surface (201; 301) and the second surface (202; 302), respectively; an electrical transmission unit (23; 23b; 23c; 33) formed on the first film (21; 31) or the first surface (201; 301) for transmitting the electrical signal; at least one signal conversion unit (24; 24a~c; 34) mounted on and electrically connected to the electrical transmission unit (23; 23b; 23c; 33), for converting the electrical signal into a corresponding optical signal or converting the optical signal into a corresponding electrical signal; and a first optical waveguide structure (26; 26a~c; 36) made of the same silicon as the semiconductor substrate (20; 30) and formed on the second film (22; 32), and the first optical waveguide structure (26; 26a~c; 36) having a reflector (263; 363) at a first end (261; 361) and a waveguide body (260; 360), the position of the reflector (263; 363) corresponding to the signal conversion unit (24; 24a∼c; 34), wherein the corresponding optical signal sequentially passes the first film (21; 21a), the semiconductor substrate and the second film and enters the first optical waveguide structure (26; 26a∼c; 36) so that the corresponding optical signal is reflected by the reflector and transmitted in the waveguide body to a second end of the first optical waveguide structure (26; 26a∼c), the second end, in case the optical coupler module (2; 2a; 2b; 3) is pluggably coupled to the optical transmission element (60; 63; 66; 80; 90), optically coupled to the optical transmission element (60; 63; 66; 80; 90); or the optical signal is transmitted in the waveguide body from the second end of the first optical waveguide structure (26a∼c; 36) and reflected by the reflector, and the optical signal sequentially passes the second film, the semiconductor substrate and the first film to reach the signal conversion unit (24; 24a∼c; 34) to be converted into the corresponding electrical signal. a semiconductor substrate (20; 30) made of silicon and having a first surface (201; 301) and a second surface (202; 302) opposite to the first surface (201; 301); a first film (21; 21a; 31) and a second film (22; 32) formed on the first surface (201; 301) and the second surface (202; 302), respectively; an electrical transmission unit (23; 23b; 23c; 33) formed on the first film (21; 31) or the first surface (201; 301) for transmitting the electrical signal; at least one signal conversion unit (24; 24a~c; 34) mounted on and electrically connected to the electrical transmission unit (23; 23b; 23c; 33), for converting the electrical signal into a corresponding optical signal or converting the optical signal into a corresponding electrical signal; and a first optical waveguide structure (26; 26a~c; 36) made of the same silicon as the semiconductor substrate (20; 30) and formed on the second film (22; 32), and the first optical waveguide structure (26; 26a~c; 36) having a reflector (263; 363) at a first end (261; 361) and a waveguide body (260; 360), the position of the reflector (263; 363) corresponding to the signal conversion unit (24; 24a∼c; 34), wherein the corresponding optical signal sequentially passes the first film (21; 21a), the semiconductor substrate and the second film and enters the first optical waveguide structure (26; 26a∼c; 36) so that the corresponding optical signal is reflected by the reflector and transmitted in the waveguide body to a second end of the first optical waveguide structure (26; 26a∼c), the second end, in case the optical coupler module (2; 2a; 2b; 3) is pluggably coupled to the optical transmission element (60; 63; 66; 80; 90), optically coupled to the optical transmission element (60; 63; 66; 80; 90); or the optical signal is transmitted in the waveguide body from the second end of the first optical waveguide structure (26a∼c; 36) and reflected by the reflector, and the optical signal sequentially passes the second film, the semiconductor substrate and the first film to reach the signal conversion unit (24; 24a∼c; 34) to be converted into the corresponding electrical signal.