a circuit board provided with a through hole;

a thermally conductive substrate fixed to the circuit board and comprising a first surface, a second surface, a connecting end, a first bearing seat, a second bearing seat and a third bearing seat; wherein the first surface and the second surface are opposite to each other; the connecting end connects the first surface and the second surface; the first bearing seat, the second bearing seat and the third bearing seat are disposed on the first surface; the area of the second surface is smaller than that of the first surface; part of the first surface contacts the circuit board; and the first bearing seat, the second bearing seat and the third bearing seat are exposed from the through opening;

a structural adhesive covering the connecting end and part of the circuit board to fix the thermally conductive substrate on the circuit board;

a silicon photonic chip disposed on the first bearing seat, electrically connected to the circuit board, and configured to output a first optical signal and receive a second optical signal and a third optical signal;

a laser assembly disposed on the second bearing seat and configured to provide the third optical signal to the silicon photonic chip; and

an optical fiber array assembly comprising an optical fiber array and a joint configured to fix an end of the optical fiber array, wherein the joint is glued to the third bearing seat to make the optical fiber array coupled and connected with the silicon photonic chip, to receive the first optical signal from the silicon photonic chip and provide the second optical signal to the silicon photonic chip; and a clearance area is provided between the optical fiber array near the joint and the thermally conductive substrate.