Optical transmitter-receiver
View Patent ↗An optical transmitter-receiver includes an optical integrated device in which at least an optical modulator and an optical detector are integrated as optical devices over the same substrate and an insulating layer is provided between the optical modulator and the substrate and between the optical detector and the substrate, and an electronic circuit chip that is connected to the optical integrated device and includes an electronic circuit including a ground wiring line. The optical integrated device includes a shield electrode between the optical modulator and the optical detector, and the shield electrode is provided sandwiching the insulating layer with the substrate to configure a capacitance and is connected to the ground wiring line of the electronic circuit chip. By the optical transmitter-receiver, crosstalk through the capacitance between the optical modulator and the substrate, the substrate, and the capacitance between the optical detector and the substrate can be suppressed to suppress deterioration of the reception characteristic.
1. An optical transmitter-receiver, comprising:
an optical integrated device in which at least an optical modulator and an optical detector are integrated as optical devices over the same substrate and an insulating layer is provided between the optical modulator and the substrate and between the optical detector and the substrate; and
an electronic circuit chip that is connected to the optical integrated device and includes an electronic circuit including a ground wiring line; and wherein
the optical integrated device includes a shield electrode between the optical modulator and the optical detector; and
the shield electrode is provided sandwiching the insulating layer with the substrate to configure a capacitance and is connected to the ground wiring line of the electronic circuit chip.
2. The optical transmitter-receiver according to claim 1 , wherein the substrate is a substrate having a resistivity of 100 ωcm or more.
3. The optical transmitter-receiver according to claim 1 , wherein the substrate is a silicon substrate; and
the insulating layer is an SiO 2 layer.
4. The optical transmitter-receiver according to claim 1 , wherein the optical detector includes a signal terminal and a bias terminal and is provided such that the signal terminal is positioned at the side far from the optical modulator; and
the electronic circuit chip includes a chip side bias terminal connected to the bias terminal of the optical detector and a capacitive element provided between the chip side bias terminal and the ground wiring line.
5. The optical transmitter-receiver according to claim 1 , wherein the electronic circuit chip is flip chip mounted on the optical integrated device; and
the shield electrode is connected to the ground wiring line of the electronic circuit chip through a bump.
6. The optical transmitter-receiver according to claim 1 , wherein the shield electrode is an electrode that is not connected to the optical device provided in the optical integrated device.
7. The optical transmitter-receiver according to claim 1 , wherein the shield electrode is provided on the surface of the optical integrated device.
8. The optical transmitter-receiver according to claim 1 , wherein the shield electrode is provided in the inside of the optical integrated device so as to be near to the substrate rather than the surface of the optical integrated device; and
the optical integrated device includes a shield wiring line that is connected to the shield electrode and extends to the surface of the optical integrated device.
9. The optical transmitter-receiver according to claim 1 , wherein the shield electrode is provided in plane.
10. The optical transmitter-receiver according to claim 1 , wherein the shield electrode is provided discretely.
11. The optical transmitter-receiver according to claim 1 , wherein the optical modulator is an optical modulator driven by a differential signal and includes a first signal terminal and a second signal terminal to which the differential signal is inputted;
the optical detector includes a signal terminal and a bias terminal;
the first signal terminal and the second signal terminal of the optical modulator are provided so as to be symmetric with respect to a line passing the center of the signal terminal of the optical detector; and
the shield electrode is provided so as to be symmetric with respect to a line passing the center of the signal terminal of the optical detector.
12. The optical transmitter-receiver according to claim 11 , wherein the optical detector is provided such that the signal terminal is positioned at the side far from the optical modulator; and
the electronic circuit chip includes a chip side bias terminal connected to the bias terminal of the optical detector and a capacitive element provided between the chip side bias terminal and the ground wiring line.