In an optical communications system, an optical module is mainly configured to implement optical-to-electrical conversion and electrical-to-optical conversion, that is, convert a to-be-sent data signal into an optical signal and send the optical signal to a peer end by using an optical fiber, and after receiving, from the optical fiber, an optical signal sent by the peer end and converting the optical signal into an electrical signal, recover received data from the electrical signal.
Currently, an optical component mainly has two packaging manners: a miniature device (XMD) and a Transistor-Outline Can (TO-CAN). If precision of a transmit wavelength of an optical transmitter needs to be ensured, the optical transmitter needs to have a cooling function. In an existing solution, thermoelectric coolers (TECs) are all packaged inside a housing (a TO-CAN or an XMD). Most TECs are placed above a base of the optical component. However, a principle of the TEC is to manufacture the TEC by using a Peltier effect of a semiconductor material. The Peltier effect is a phenomenon that when a direct current passes through a galvanic couple formed by two types of semiconductor materials, one end of the galvanic couple absorbs heat, and the other end dissipates heat. In a current existing typical design, the TECs are all placed inside the packaging housing (the TO-CAN or the XMD). That is, heat absorption and heat dissipation phenomena of the TEC exist in one environment. The heat dissipation phenomenon causes an increase in temperature of the packaging housing and an increase in a temperature inside the housing. This increases a cooling burden of the TEC. That is, power consumption of the TEC is increased and precision of the optical transmitter is affected.