Electro-optic modulator, optical chip, and integrated chip
An electro-optic modulator is disposed on a surface of a substrate including: an optical waveguide layer disposed on the substrate, a modulation electrode disposed on the optical waveguide layer, and a metal electrode disposed on the modulation electrode and electrically connected to the modulation electrode. A first end of the metal electrode is coupled to a radio frequency driver, and receives a modulation signal input by the radio frequency driver. The modulation electrode is configured to perform electro-optic modulation on the optical waveguide layer based on the modulation signal. A second end of the metal electrode is coupled to a direct-current voltage end, and the direct-current voltage end is configured to input a voltage signal and provide a bias voltage for the radio frequency driver by using the metal electrode. This reduces costs and a size of the electro-optic modulator, and is conducive to device miniaturization.
1 . An electro-optic modulator disposed on a surface of a substrate, the electro-optic modulator comprising:
an optical waveguide layer disposed on the substrate;
modulation electrodes disposed on the optical waveguide layer; and
a dual-rail metal electrode disposed on and electrically connected to the modulation electrodes, a first end of the dual-rail metal electrode connected to a radio frequency driver, the dual-rail metal electrode being configured and connected to receive a modulation signal input from the radio frequency driver and apply the received modulation signal input to the modulation electrodes,
the modulation electrodes configured to perform electro-optic modulation on the optical waveguide layer based on the modulation signal input,
a second end of the dual-rail metal electrode electrically connected to a direct-current voltage terminal for supplying a direct-current bias voltage, the dual-rail metal electrode configured to carrying carry the direct-current bias voltage from the direct-current voltage terminal at the metal electrode second end to the radio frequency driver at the dual-rail metal electrode first end through direct-current coupling,
the optical waveguide layer comprising:
an electro-optic crystal layer parallel to the substrate, and
a ridge waveguide disposed on a side of the electro-optic crystal layer that is away from the substrate surface, the modulation electrodes configured to perform electro-optic modulation on a light wave transmitted by the ridge waveguide,
the ridge waveguide comprising:
a first branch and a second branch that are symmetrically disposed,
an input end of the first branch coupled to an input end of the second branch, an output end of the first branch coupled to an output end of the second branch, a first end of the modulation electrodes coupled to the input ends of the first branch and the second branch, and a second end of the modulation electrodes coupled to the output ends of the first branch and the second branch; and
the first end of the modulation electrodes coupled to a signal output end of the radio frequency driver, the second end of the modulation electrode connected to a terminal resistor, and a phase of an optical signal that is output from the first branch opposite to a phase of an optical signal that is output from the second branch,
wherein the modulation electrodes comprise a first electrode pair and a second electrode pair, the first electrode pair symmetrically disposed on first and second sides of the first branch, and the second electrode pair symmetrically disposed on first and second sides of the second branch, and
wherein the dual-rail metal electrode is disposed on the first side and the second side of both the first branch and the second branch and is configured to provide a differential voltage to the first electrode pair and the second electrode pair.
2 . The electro-optic modulator according to claim 1 , further comprising: an insulation layer disposed on the surface of the substrate, wherein the optical waveguide layer and the modulation electrodes are located in the insulation layer, the insulation layer defining an opening on a surface of the modulation electrodes, the metal electrode being formed at the opening.
3 . The electro-optic modulator according to claim 1 , wherein the metal electrode is continuously disposed, and the modulation electrodes are discontinuously disposed.
4 . The electro-optic modulator according to claim 1 , wherein:
the optical waveguide layer comprises an electro-optic material,
the first electrode pair is configured and connected to apply a direction of an electric field to the first branch that is the same as a direction of an electric field applied to the second branch by the second electrode pair, and
a polarization direction of the first branch is opposite to a polarization direction of the second branch.
5 . The electro-optic modulator according to claim 4 , wherein:
a first end of the first electrode pair is configured to be connected to the signal output end of the radio frequency driver,
a second end of the first electrode pair is connected to a first end of the second electrode pair,
a second end of the second electrode pair is connected to a terminal resistor,
the first branch and the second branch each comprise a first part and a second part,
the first part of the first branch is opposite to the first part of the second branch,
the second part of the first branch is opposite to the second part of the second branch,
the first electrode pair is disposed on sides of the first part of the first branch, and
the second electrode pair is disposed on sides of the second part of the second branch.
6 . The electro-optic modulator according to claim 4 , wherein:
first ends of the first electrode pair and the second electrode pair are configured to be separately connected to the signal output end of the radio frequency driver,
both second ends of the first electrode pair and the second electrode pair are connected to a terminal resistor;
the first electrode pair comprises a first electrode and a second electrode,
the second electrode pair comprises a third electrode and a fourth electrode,
the first electrode and the second electrode are located on sides of the first branch and the second branch,
the third electrode and the fourth electrode are located between the first branch and the second branch,
the first electrode and the third electrode are connected to a positive electrode of the signal output end of the radio frequency driver, and
the second electrode and the fourth electrode are configured to be connected to a negative electrode of the signal output end of the radio frequency driver.
7 . The electro-optic modulator according to claim 1 , wherein:
a direction of an electric field applied to the first branch by the first electrode pair is opposite to a direction of an electric field applied to the second branch by the second electrode pair, and
a polarization direction of the first branch is the same as a polarization direction of the second branch.
8 . The electro-optic modulator according to claim 7 , wherein:
the modulation electrodes further comprises a third electrode pair,
a first end of the first electrode pair is configured to be connected to the signal output end of the radio frequency driver,
a second end of the first electrode pair is connected to a first end of the second electrode pair,
a first end of the third electrode pair is connected to a second end of the second electrode pair,
a second end of the third electrode pair is connected to a terminal resistor;
the first branch and the second branch each comprise a first part, a second part, and a third part that are distributed in an S shape and that are parallel to each other, the second part is located between the first part and the third part,
the first electrode pair is disposed on two sides of the first part of the first branch,
the second electrode pair is disposed on two sides of the second part of the second branch,
the third electrode pair is disposed on two sides of the third part of the first branch, and
a direction of an electric field applied to the first branch by the third electrode pair is opposite to a direction of an electric field applied to the second branch by the second electrode pair.
9 . The electro-optic modulator according to claim 7 , wherein:
first ends of the first electrode pair and the second electrode pair are separately connected to the signal output end of the radio frequency driver,
both second ends of the first electrode pair and the second electrode pair are connected to a terminal resistor,
the first electrode pair comprises a first electrode and a second electrode,
the second electrode pair comprises a third electrode and a fourth electrode,
the first electrode and the second electrode are located on sides of the first branch and the second branch,
the third electrode and the fourth electrode are located between the first branch and the second branch,
the first electrode and the fourth electrode are connected to a positive electrode of the signal output end of the radio frequency driver, and
the second electrode and the third electrode are configured to be connected to a negative electrode of the signal output end of the radio frequency driver.
10 . The electro-optic modulator according to claim 1 , wherein the modulation electrodes comprises copper, zinc, or a transparent conductive oxide.
11 . The electro-optic modulator of claim 1 wherein the modulation electrodes are configured to perform push-pull electro-optic modulation on the optical waveguide layer.
12 . The integrated chip of claim 11 wherein the direct-current voltage terminal is configured to provide the bias voltage for the radio frequency driver through plural open-circuit direct-current coupling electrical paths that are free of DC-blocking capacitors.
13 . An optical chip comprising:
a substrate, and
an electro-optic modulator disposed on a surface of a substrate, the electro-optic modulator comprising:
an optical waveguide layer disposed on the substrate;
modulation electrodes disposed on the optical waveguide layer; and
a dual-rail metal electrode disposed on and electrically connected to the modulation electrodes,
a first end of the dual-rail metal electrode connected to a radio frequency driver, the dual-rail metal electrode being configured and connected to supply power to the radio frequency driver through a direct-current coupling free of inline DC blocking capacitors;
the dual-rail metal electrode configured to receive a modulation signal input from the radio frequency driver,
the modulation electrode configured to perform electro-optic modulation on the optical waveguide layer based on the modulation signal input;
a second end of the dual-rail metal electrode connected to a direct-current voltage terminal, and
the direct-current voltage terminal being configured to input a voltage and provide a direct-current bias voltage for the radio frequency driver through the dual-rail metal electrode,
wherein the optical waveguide layer comprises: an electro-optic crystal layer parallel to the substrate, and a ridge waveguide disposed on a side of the electro-optic crystal layer that is away from the substrate surface, the modulation electrodes are configured to perform electro-optic modulation on a light wave transmitted by the ridge waveguide,
the ridge waveguide comprising:
a first branch and a second branch that are symmetrically disposed,
an input end of the first branch is coupled to an input end of the second branch, an output end of the first branch is coupled to an output end of the second branch, a first end of the modulation electrodes is coupled to the input ends of the first branch and the second branch, and a second end of the modulation electrodes is coupled to the output ends of the first branch and the second branch; and
the first end of the modulation electrodes is coupled to a signal output end of the radio frequency driver, the second end of the modulation electrode is connected to a terminal resistor, and a phase of an optical signal that is output from the first branch is opposite to a phase of an optical signal that is output from the second branch,
the modulation electrodes comprise a first electrode pair and a second electrode pair, the first electrode pair is symmetrically disposed on first and second sides of the first branch, and the second electrode pair is symmetrically disposed on first and second sides of the second branch, and
wherein the dual-rail metal electrode is disposed on the first side and the second side of both the first branch and the second branch and is configured to provide a differential voltage to the first electrode pair and the second electrode pair.
14 . The optical chip according to claim 13 , further comprising an input waveguide and an output waveguide, wherein the input waveguide is connected to an input end of an optical waveguide layer, and the output waveguide is connected to an output end of the optical waveguide layer.
15 . The optical chip according to claim 14 , further comprising: a photoelectric detector connected to the output waveguide by using a connection waveguide, the photoelectric detector configured to detect a modulated optical signal.
16 . An integrated chip comprising:
an electrical chip, and
an optical chip,
the electrical chip being disposed on a surface of the optical chip,
the electrical chip being connected to the optical chip through welding by using a solder ball,
the optical chip comprising a substrate and an electro-optic modulator disposed on a surface of a substrate,
the electro-optic modulator comprising:
an optical waveguide layer disposed on the substrate;
modulation electrodes disposed on the optical waveguide layer; and
a dual-rail metal electrode disposed on the modulation electrode and electrically connected to the modulation electrodes,
a first end of the dual-rail metal electrode connected to a radio frequency driver;
the dual-rail metal electrode being configured to receive a modulation signal input from the radio frequency driver,
the dual-rail metal electrode being connected to provide direct-current coupling to the radio frequency driver free of inline DC blocking capacitors,
the modulation electrodes being configured to perform electro-optic modulation on the optical waveguide layer based on the modulation signal input;
a second end of the dual-rail metal electrode being configured to be coupled to a direct-current voltage terminal configured to input a voltage and provide a direct-current bias voltage for the radio frequency driver by using the dual-rail metal electrode;
wherein the optical waveguide layer comprises: an electro-optic crystal layer parallel to the substrate, and a ridge waveguide disposed on a side of the electro-optic crystal layer that is away from the substrate surface, the modulation electrodes are configured to perform electro-optic modulation on a light wave transmitted by the ridge waveguide,
the ridge waveguide comprising:
a first branch and a second branch that are symmetrically disposed,
an input end of the first branch is coupled to an input end of the second branch, an output end of the first branch is coupled to an output end of the second branch, a first end of the modulation electrodes is coupled to the input ends of the first branch and the second branch, and a second end of the modulation electrodes is coupled to the output ends of the first branch and the second branch; and
the first end of the modulation electrodes is coupled to a signal output end of the radio frequency driver, the second end of the modulation electrode is connected to a terminal resistor, and a phase of an optical signal that is output from the first branch is opposite to a phase of an optical signal that is output from the second branch,
the modulation electrodes comprise a first electrode pair and a second electrode pair, the first electrode pair is symmetrically disposed on first and second sides of the first branch, and the second electrode pair is symmetrically disposed on first and second sides of the second branch, and
wherein the dual-rail metal electrode is disposed on the first side and the second side of both the first branch and the second branch and is configured to provide a differential voltage to the first electrode pair and the second electrode pair.
17 . The integrated chip of claim 16 further comprising a radio frequency driver, the first end of the metal electrode is coupled to the radio frequency driver so that the first end of the modulation electrodes is coupled to the signal output end of the radio frequency driver.