Recently, there have been increasing demands for high-speed signal transmissions in the field of supercomputers, high-end servers, and the like. Next-generation interfaces currently being developed, such as InfiniBand Trade Association's Enhanced Data Rate (IBTA EDR) and 100 Gigabit Ethernet (registered trademark), have an extended distance of signal transmissions, e.g., several-ten meters. Therefore, there has been increased use of optical communications capable of supporting high speed signal transmissions with an extended transmission distance.
In optical communications, optical modules are used to perform conversions between an electric signal and light. In the frontplane or the backplane of a high-end server, for example, an optical module is used in a connection between an optical cable and a server blade. The optical module converts the light received from the optical cable into an electric signal, and outputs the electric signal to the server blade. The optical module also converts an electric signal received from the server blade into light, and outputs the light to the optical cable.
In the housing of an optical module, a “photoelectric transducer” for performing conversions between an electric signal and light is provided. A photoelectric transducer is a flexible printed circuit (FPC) implemented with a photoemitter, a driver integrated circuit (IC) for driving the photoemitter, a photoreceiver, and a trans-impedance amplifier (TIA) for converting a current received from the photoreceiver into a voltage. A related-art example is disclosed in Japanese Laid-open Patent Publication No. 2012-068539.
The photoelectric transducer becomes highly heated as it operates. The driver IC and the TIA are the main sources of the heat. Hence, when the heat released from the photoelectric transducer stays in the housing of the optical module, the temperature rises inside of the housing, and such a temperature rise may cause malfunctioning of the photoemitter and the photoreceiver, or deformation of the FPC, for example, and result in failure of the optical module.