Optical Communication Element
A COSA as an optical communication component that can prevent energy radiated in a package from causing performance degradation includes a DC block capacitor that is mounted on an upper surface of the package and located at a position different from those of a SiP chip and an optical modulator driver IC to cut off a DC signal included in a RF signal to be transmitted to the IC and a lid provided over an upper portion of the package. A separation projecting portion of the lid projecting toward an upper surface of the package separately defines a region where the capacitor is present and a region where the SiP chip and the IC are present. The separation projecting portion is connected to GND of the package, and the lid is at a GND potential.
1 . An optical communication component comprising:
a package having a flat plate shape;
an optical communication element mounted on an upper surface of the package;
an electronic circuit element mounted on the upper surface of the package and located at a position different from that of the optical communication element;
a direct-current block device mounted on the upper surface of the package and located at a position different from those of the optical communication element and the electronic circuit element to cut off a direct-current signal included in a high-frequency signal transmitted to the electronic circuit element via a conductive pattern provided on the package; and
a lid provided over an upper portion of the package to cover the optical communication element, the electronic circuit element, and the direct-current block device,
the lid having a separation projecting portion that projects toward the upper surface of the package to separately define a region where the direct-current block device is present and a region where the optical communication element and the electronic circuit element are present.
2 . The optical communication component according to claim 1 , wherein the lid is at a ground potential.
3 . The optical communication component according to claim 1 , wherein the conductive pattern on the package includes RF wires placed to connect, as a whole, the direct-current block device, the electronic circuit element, and the optical communication element such that the direct-current block device is interposed between the RF wires.
4 . The optical communication component according to claim 3 , wherein a portion of each of the RF wires has a wiring structure in which the portion of the RF wire temporarily extends into an inner layer of the package via one metal via wire and then returns again to a surface layer via another metal via wire at another position.
5 . The optical communication component according to claim 4 , wherein
a ground electrode is provided in a surface layer of the metal via wire and
the ground electrode is electrically connected to a tip surface of the separation projecting portion of the lid.
6 . The optical communication component according to claim 5 , wherein the ground electrode and the tip surface of the separation projecting portion of the lid are maintained in an electrically connected state by adhesive fixation using an adhesive.
7 . The optical communication component according to claim 6 , wherein the adhesive is a non-conductive adhesive adhesively fixing a side wall of the separation projecting portion in the vicinity of the tip surface thereof to a top surface of the package or a conductive adhesive adhesively fixing the ground electrode to the tip surface of the separation projecting portion.
8 . An optical communication component according to claim 1 , wherein
a material of the lid is a metal material having a high thermal conductivity and a material of the package has a thermal expansion coefficient close to that of a printed circuit board serving as a connection partner.