A lithium niobate intensity modulator and optical transceiver module

Abstract

The present invention provides a lithium niobate intensity modulator and an optical transceiver module, comprising a substrate, a waveguide and a traveling wave electrode, wherein the waveguide and the traveling wave electrode are both formed on the substrate, a traveling wave electrode is arranged on the substrate, the traveling wave electrode is arranged along the axial direction of the waveguide, the middle part of the traveling wave electrode has an inwardly concave groove, so that a connecting part is formed in the middle part, the diameter of the connecting part is smaller than the diameter of the traveling wave electrode except for the part thereof, two waveguides are arranged on the substrate, the opposite ends of the two waveguides are spaced apart and are respectively close to the ends of the groove, and the traveling wave electrode pairs on both sides of the groove can respectively perform relative unidirectional modulation on the optical signal on the waveguide. The present invention, on the basis of realizing bidirectional modulation, the lithium niobate intensity modulator has a small device volume and a high degree of integration of peripheral circuits, which can further contribute to space saving.

Description

Technical Field

[0001] The present invention relates to the technical field of phase modulators, in particular to a lithium niobate intensity modulator and an optical transceiver module. Background Art

[0002] Lithium niobate modulators have excellent properties such as large transmission capacity, high transmission quality, long relay distance, good anti-electromagnetic interference performance, and good confidentiality performance. They are widely used in optical transceiver systems in the fields of high-speed network computer interconnection, sensor fusion, data fusion, image fusion, integrated detection, optically controlled phased array radar, electronic warfare, etc.

[0003] The conventional existing lithium niobate intensity modulator can only modulate the optical signal in a single direction. In order to solve this problem, in the prior art solution, the lithium niobate phase modulator with bidirectional modulation is disclosed in the authorization announcement number CN105607299B, such as Figure 1 As shown, it has two traveling wave electrodes 3, one of which can unidirectionally modulate the optical signal transmitted from end A to end B on the strip waveguide 2, and the other traveling wave electrode 3 can unidirectionally modulate the optical signal transmitted from end B to end A on the waveguide 2. This prior art solution uses two traveling wave electrodes for modulation, and its device size is miniaturized and the integration of peripheral circuits can be further improved. Summary of the invention

[0004] The object of the present invention is to provide a lithium niobate intensity modulator and an optical transceiver module to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A lithium niobate intensity modulator comprises a substrate, a waveguide and a traveling wave electrode, wherein the waveguide and the traveling wave electrode are both formed on the substrate, a traveling wave electrode is arranged on the substrate, the traveling wave electrode is arranged along the axial direction of the waveguide, the middle part of the traveling wave electrode has an inwardly recessed groove, so that a connecting part is formed in the middle part, the diameter of the connecting part is smaller than the diameter of the traveling wave electrode except the connecting part, two waveguides are arranged on the substrate, the opposite ends of the two waveguides are spaced apart and are respectively close to the ends of the groove, and the traveling wave electrode pairs on both sides of the groove can respectively perform relative unidirectional modulation on the optical signal on the waveguide.

[0007] Preferably, the resistivity of the connecting portion is greater than the resistivity of the traveling wave electrode other than the connecting portion.

[0008] Preferably, it further comprises a metal mesh, wherein the metal mesh comprises a first metal mesh, and the first metal mesh is located in the groove and wrapped around the connecting portion.

[0009] Preferably, the metal mesh further includes a second metal mesh, a portion of mesh wires of the second metal mesh passes through the connecting portion and is connected to the first metal mesh.

[0010] Preferably, the port corresponding to the traveling wave electrode comprises a radio frequency input terminal and a matching resistor connection terminal, wherein the radio frequency input terminal is respectively located on both sides of the slot.

[0011] Preferably, the RF input terminal is matched with impedance.

[0012] Preferably, the matching resistor connection end is connected in series with a switch matching resistor.

[0013] To achieve the above object, the present invention also provides the following technical solutions:

[0014] An optical transceiver module comprises an antenna and a lithium niobate intensity modulator as described in any one of the above, wherein the antenna receives and transmits signals through a matching resistor connection end.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] In the present invention, only one traveling wave electrode is used to form two modulation areas, the first modulation area is located on the left, the second modulation area is located on the right, the RF input end corresponding to the first modulation area is located on the right side of the first modulation area, the matching resistor connection end corresponding to the first modulation area is located on the left side of the first modulation area, the RF input end corresponding to the second modulation area is located on the left side of the second modulation area, and the matching resistor connection end corresponding to the second modulation area is located on the right side of the second modulation area; both RF input ends are electrically connected to a power distribution module. After adopting this scheme, the traveling wave electrode can share a set of microwave signal generating circuits, and the RF signals output by the microwave signal generating circuits are distributed by the power distribution module and then input into the traveling wave electrodes by the corresponding RF input ends.

[0017] In the present invention, the ports of the traveling wave electrode are located on the same side of the lithium niobate substrate. After adopting this solution, compared with the existing technical solution, the corresponding peripheral circuits and devices can be arranged on the same side of the lithium niobate substrate, which can further help save space; on the basis of realizing bidirectional modulation, the device volume is smaller and the peripheral circuit integration is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of a lithium niobate intensity modulator used for modulating bidirectional optical signals in the prior art;

[0019] Figure 2 It is a schematic diagram of the overall structure of the present invention;

[0020] Figure 3 Another schematic diagram of the overall structure of the present invention.

[0021] In the figure: 1 substrate, 2 waveguide, 3 traveling wave electrode, 4 RF input terminal, 5 matching resistor connection terminal, 6 resistor, 7 power distribution module, 8 slot, 9 connecting part, 10 metal mesh, 11 first metal mesh, 12 second metal mesh, 13 impedance, 14 switch, 15 antenna. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example:

[0024] See also Figures 1 to 3 , the present invention provides a technical solution:

[0025] A lithium niobate intensity modulator comprises a substrate 1, a waveguide 2 and a traveling wave electrode 3, wherein the waveguide 2 and the traveling wave electrode 3 are both formed on the substrate 1, a traveling wave electrode 3 is arranged on the substrate 1, the traveling wave electrode 3 is arranged along the axial direction of the waveguide 2, the middle part of the traveling wave electrode 3 has an inwardly recessed groove 8, so that a connecting part 9 is formed in the middle part, the diameter of the connecting part 9 is smaller than the diameter of the traveling wave electrode 3 except the connecting part, two waveguides 2 are arranged on the substrate 1, the opposite ends of the two waveguides 2 are spaced apart and are respectively close to the ends of the groove 8, and the pairs of traveling wave electrodes 3 on both sides of the groove 8 can respectively perform relative unidirectional modulation on the optical signal on the waveguide 2.

[0026] Specifically, in the present invention, the substrate 1 can be an X-cut lithium niobate substrate or a Z-cut lithium niobate substrate. During operation, the laser provides a continuous optical carrier for the lithium niobate intensity modulator. Based on the fact that the lithium niobate intensity modulator can utilize the electro-optical effect of the lithium niobate crystal, the phase of the optical signal in the optical waveguide is modulated by applying a microwave signal to the traveling wave electrode 3. The microwave field can be effective when the transmission direction is the same as the transmission direction of the optical wave in the (optical) waveguide 2, and the optical wave cannot be effectively modulated in the opposite direction.

[0027] Based on this, Figure 2As shown, by setting a concave groove 8 in the middle of the traveling wave electrode 3 and forming a connecting portion 9, the waveguide 2 is cut off in the middle, that is, two waveguides 2 are formed, and the ends of the two waveguides 2 approaching each other are close to the ends of the groove 8, so that the middle of the traveling wave electrode 3 and the waveguide 2 move relative to each other in the axial direction, so that the middle of the traveling wave electrode 3 moves outside the waveguide 2, so that the electric field of this part is far away from the optical waveguide and does not work for electro-optical modulation; the groove 8 can improve the response when the traveling wave electrode 3 modulates the optical signal and output it quickly from the matching resistor connection end 5. Therefore, the radio frequency signal output by the microwave signal generating circuit is distributed by the power distribution module 7 and then input into the corresponding traveling wave electrodes on the left and right for unidirectional modulation, and then output by the two matching resistor connection ends 5.

[0028] Specifically, in the present invention, Figure 2 As shown, the resistivity of the connection portion 9 is greater than the resistivity of the traveling wave electrode 3 except for the connection portion 9. The dielectric loss generated by the middle connection portion 9 of the traveling wave electrode 3 is greater than that of the traveling wave electrode 3 except for the connection portion 9, so as to ensure that the microwave signal entering from the left RF input terminal 4 can be modulated by the optical signal of the traveling wave electrode on the left in the corresponding direction, and the microwave signal entering from the right RF input terminal 4 can be modulated by the optical signal of the traveling wave electrode on the right in the corresponding direction, without affecting the optical signal transmitted in the reverse direction, so that the optical signals in two directions can be modulated simultaneously, greatly improving the integration of the bidirectional modulator.

[0029] Specifically, in the present invention, Figure 3 As shown, it also includes a shielding part, which adopts a metal mesh 10. The metal mesh 10 includes a first metal mesh 11, which is located in the groove 8 and wrapped on the connecting part 9. The metal mesh 10 also includes a second metal mesh 12, a part of the mesh of the second metal mesh 12 passes through the connecting part 9 and is connected to the first metal mesh 11. The ports corresponding to the traveling wave electrode 3 include a radio frequency input terminal 4 and a matching resistor connection terminal 5, wherein the radio frequency input terminal 4 is respectively located on both sides of the groove 8. In order to ensure that the microwave signals entering from the two radio frequency input terminals 4 at the same time will not cross, thereby affecting the simultaneous modulation of the optical signal, the metal mesh 10 is further used as a signal shielding block. In particular, the second metal mesh 12 is perpendicular to the connecting part 9, and the connection between the connecting part 9 and the second metal mesh 12 is similar to a woven and interlaced state, thereby realizing the simultaneous modulation of the optical signals in two directions, so that the modulator has a higher transmit and receive isolation.

[0030] Specifically, in the present invention, Figure 3As shown, the RF input terminal 4 is matched with an impedance 13. The matching resistor connection terminal 5 is matched with a resistor 6 by connecting a switch 14 in series. The matching impedance 13 is used to reduce the transmission power of the power distribution module 7 and reduce power loss. The switch 14 is set to facilitate the adjustment of the resistor 6 to adapt to electro-optical modulation of different frequencies.

[0031] In the present invention, only one traveling wave electrode 3 is used to form two modulation areas. Figure 3 For example, the first modulation area is located on the left, the second modulation area is located on the right, the RF input terminal 4 corresponding to the first modulation area is located on the right side of the first modulation area, the matching resistor connection terminal 5 corresponding to the first modulation area is located on the left side of the first modulation area, the RF input terminal 4 corresponding to the second modulation area is located on the left side of the second modulation area, and the matching resistor connection terminal 5 corresponding to the second modulation area is located on the right side of the second modulation area; both RF input terminals 4 are electrically connected to a power distribution module 7. After adopting this solution, the traveling wave electrode 3 can share a set of microwave signal generating circuits, and the RF signal output by the microwave signal generating circuit is distributed by the power distribution module 7 and then input into the traveling wave electrode 3 by the corresponding RF input terminals 4.

[0032] In the present invention, the ports of the traveling wave electrode 3 are located on the same side of the lithium niobate substrate. With this solution, compared with the prior art solution, the corresponding peripheral circuits and devices can be arranged on the same side of the lithium niobate substrate, which can further help save space; on the basis of achieving bidirectional modulation, the device size is smaller and the peripheral circuit integration is higher.

[0033] An optical transceiver module includes an antenna 15 and the lithium niobate intensity modulator as described above, wherein the antenna 15 receives and transmits signals through a matching resistor connection terminal 5. The detailed structure of the optical transceiver module can refer to the above embodiment, which will not be described in detail here; it can be understood that since the above lithium niobate intensity modulator is used in the optical transceiver module of the present invention, the embodiment of the optical transceiver module of the present invention includes all technical solutions of all embodiments of the above lithium niobate intensity modulator, and the technical effects achieved are also exactly the same, which will not be described in detail here.

[0034] The remaining parts of the present invention that are not described may be the same as the prior art, or are well-known technologies, or may be implemented by using the prior art, and will not be described in detail here.

[0035] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A lithium niobate intensity modulator, characterized in that: The invention comprises a substrate (1), a waveguide (2) and a traveling wave electrode (3), wherein the waveguide (2) and the traveling wave electrode (3) are both formed on the substrate (1), a traveling wave electrode (3) is arranged on the substrate (1), the traveling wave electrode (3) is arranged along the axial direction of the waveguide (2), the middle part of the traveling wave electrode (3) has an inwardly recessed groove (8), so that a connecting part (9) is formed in the middle part, and the diameter of the connecting part (9) is smaller than the diameter of the traveling wave electrode (3) other than the connecting part, two waveguides (2) are arranged on the substrate (1), the opposite ends of the two waveguides (2) are spaced apart and are respectively close to the ends of the groove (8), and the traveling wave electrode (3) pairs located on both sides of the groove (8) can respectively perform relative unidirectional modulation on the optical signal on the waveguide (2).

2. A lithium niobate intensity modulator according to claim 1, characterized in that: The resistivity of the connecting portion (9) is greater than the resistivity of the traveling wave electrode (3) other than the connecting portion (9).

3. A lithium niobate intensity modulator according to claim 1, characterized in that: It also comprises a metal mesh (10), wherein the metal mesh (10) comprises a first metal mesh (11), wherein the first metal mesh (11) is located in the groove (8) and wrapped around the connecting portion (9).

4. A lithium niobate intensity modulator according to claim 3, characterized in that: The metal mesh (10) further comprises a second metal mesh (12), a portion of mesh wires of the second metal mesh (12) passing through the connecting portion (9) and connected to the first metal mesh (11).

5. The lithium niobate intensity modulator according to claim 1, characterized in that: The ports corresponding to the traveling wave electrode (3) include a radio frequency input end (4) and a matching resistor connection end (5), wherein the radio frequency input end (4) is located at two sides of the slot (8) respectively.

6. A lithium niobate intensity modulator according to claim 5, characterized in that: The radio frequency input end (4) is connected to an impedance (13).

7. The lithium niobate intensity modulator according to claim 5, characterized in that: The matching resistor connection end (5) is connected in series with a matching resistor (6) via a switch (14).

8. An optical transceiver module, characterized in that: It comprises an antenna (15) and a lithium niobate intensity modulator as claimed in any one of claims 1 to 7, wherein the antenna (15) receives and sends signals via a matching resistor connection terminal (5).

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