Light emitting chip and optical device

Abstract

The utility model provides a light emitting chip and an optical device. The light emitting chip comprises N groups of light modulation channels, P light input ports and Q light output ports, the optical signal input ends of the N groups of optical modulation channels are respectively connected with the corresponding optical input ports, the output ends of the N groups of optical modulation channels are respectively connected with the corresponding optical output ports, and each optical modulation channel modulates an input optical signal; each group of light modulation channels comprises a radio frequency filter and a traveling wave Mach-Zehnder modulator; the radio frequency filter performs high-pass filtering on the received electric signal; the optical signal input end of the traveling wave Mach-Zehnder modulator receives a corresponding optical signal, and the electric signal input end is connected with the output end of the radio frequency filter. According to the utility model, the electric signal is provided for the traveling wave Mach-Zehnder modulator after being subjected to high-pass filtering, and the frequency response of the light emitting chip is adjusted through the radio frequency filter, so that the effect of simultaneously optimizing the bandwidth and the modulation efficiency of the light emitting chip is realized, and the performance of the light emitting chip is greatly improved.

Description

Technical Field

[0001] The utility model relates to the field of optical communications, in particular to a light emitting chip and an optical device. Background Art

[0002] Silicon photonics transmitter chips based on traveling-wave Mach-Zehnder modulators (TW-MZMs) have been widely used in data centers and long-haul communications, achieving single-wavelength 100G communication rates, thanks to their high speed, high integration, and low cost. The transition to single-wavelength 200G communication rates and the development of linear-drive pluggable optical modules (LPOs) are placing higher demands on the bandwidth performance of optical transmitter chips.

[0003] The bandwidth of traditional silicon photonics transmitter chips based on traveling-wave Mach-Zehnder modulators (TWMZMs) is entirely determined by the TWM. Generally speaking, there's a trade-off between bandwidth and modulation efficiency when designing TWMZMs. Compared to TWMs used in single-wavelength 100G transmission, further increasing the TWMZM's bandwidth comes at the expense of modulation efficiency. Insufficient modulation efficiency, however, translates to higher drive voltages and power consumption, or a smaller system noise margin.

[0004] Therefore, how to achieve simultaneous optimization of the bandwidth and modulation efficiency of an optical transmitter chip has become one of the urgent problems to be solved by those skilled in the art.

[0005] It should be noted that the above technical background is merely for the purpose of providing a clear and complete description of the technical solutions of the present invention and to facilitate understanding by those skilled in the art. It should not be assumed that the above technical solutions are well known to those skilled in the art simply because they are described in the background technology section of the present invention. Utility Model Content

[0006] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a light emitting chip and an optical device to solve the problem in the prior art that the bandwidth and modulation efficiency of the light emitting chip cannot be optimized simultaneously.

[0007] To achieve the above-mentioned and other related purposes, the present invention provides a light emitting chip, which at least includes:

[0008] N groups of optical modulation channels, P optical input ports, and Q optical output ports, where M is a natural number greater than or equal to 1, and P and Q are natural numbers less than or equal to M;

[0009] The optical signal input ends of N groups of optical modulation channels are respectively connected to corresponding optical input ports, and the optical signal output ends of N groups of optical modulation channels are respectively connected to corresponding optical output ports. Each optical modulation channel modulates the input optical signal.

[0010] Each group of optical modulation channels includes a radio frequency filter and a traveling wave Mach-Zehnder modulator; the radio frequency filter performs high-pass filtering on the received electrical signal; the optical signal input end of the traveling wave Mach-Zehnder modulator receives the corresponding optical signal, and the electrical signal input end is connected to the output end of the radio frequency filter.

[0011] Optionally, the optical modulation channel is of a differential structure.

[0012] More optionally, the radio frequency filter includes a first filtering unit and a second filtering unit; the first filtering unit performs high-pass filtering on one path of the differential signal, and the second filtering unit performs high-pass filtering on the other path of the differential signal.

[0013] Optionally, the optical modulation channel is of a single-ended structure.

[0014] More optionally, the radio frequency filter includes a first filtering unit; the first filtering unit performs high-pass filtering on the electrical signal.

[0015] More optionally, each filtering unit is a passive high-pass filtering structure.

[0016] More optionally, each filtering unit includes an inductor and a resistor. One end of the inductor serves as the input / output end of the corresponding filtering unit, and the other end is grounded via the resistor.

[0017] More optionally, the traveling wave Mach-Zehnder modulator includes a Mach-Zehnder interference structure, a traveling wave phase shifter, and a radio frequency terminal;

[0018] The traveling wave phase shifter acts on the waveguide arms of the Mach-Zehnder interference structure to modulate the phase of the optical signal in the Mach-Zehnder interference structure;

[0019] The radio frequency terminal is connected to the output end of the traveling wave phase shifter.

[0020] To achieve the above and other related purposes, the present invention also provides an optical device, and the optical device at least includes the above optical emission chip.

[0021] As described above, the optical emission chip and the optical device of the present invention have the following beneficial effects:

[0022] The optical emission chip and optical device of the present utility model overcome the defect that it is difficult to optimize the bandwidth and modulation frequency of the traditional traveling-wave Mach-Zehnder modulator at the same time. After high-pass filtering the electrical signal, it is provided to the traveling-wave Mach-Zehnder modulator, and the frequency response of the optical emission chip is adjusted through a radio frequency filter, thereby achieving the effect of optimizing the bandwidth and modulation efficiency of the optical emission chip at the same time, and greatly improving the performance of the optical emission chip.

[0023] The optical emission chip and optical device of the present utility model expand the performance space of the bandwidth and modulation efficiency of the traditional silicon optical emission chip through overall optimized design of the radio frequency filter and the traveling-wave Mach-Zehnder modulator, that is, increasing the bandwidth while maintaining the modulation efficiency. Brief Description of the Drawings

[0024] Figure 1 It shows a schematic structural diagram of an optical emission chip of the present utility model.

[0025] Figure 2 It shows an example of an optical modulation channel of the present utility model.

[0026] Figure 3 It shows a circuit diagram of a radio frequency filter of the present utility model.

[0027] Figure 4 It shows a schematic structural diagram of a traveling-wave Mach-Zehnder modulator of the present utility model.

[0028] Figure 5 It shows another schematic structural diagram of a traveling-wave Mach-Zehnder modulator of the present utility model.

[0029] Figure 6 It shows a differential circuit diagram of an optical modulation channel of the present utility model. [[ID=3I]]

[0030] Figure 7 It shows a schematic diagram of the performance comparison between the optical emission chip of the present utility model and the traditional structure.

[0031] Description of Component Labels

[0032] 1 Optical emission chip

[0033] 2a First optical modulation channel

[0034] 2b Second optical modulation channel

[0035] 2c Third optical modulation channel

[0036] 2d Fourth optical modulation channel

[0037] 21 Radio frequency filter

[0038] 22 Traveling-wave Mach-Zehnder modulator

[0039] 221 Mach-Zehnder interference structure

[0040] 222 Traveling-wave phase shifter

[0041] 223 RF terminal

[0042] 22a Beam splitter

[0043] 22b First waveguide arm

[0044] 22c Second waveguide arm

[0045] 22d Combiner

[0046] 22e First traveling-wave electrode

[0047] 22f Second traveling-wave electrode

[0048] 22g First PN junction

[0049] 22h Second PN junction

[0050] 3 Optical input port

[0051] 4 Optical output port Specific implementation mode

[0052] The following uses specific specific examples to illustrate the implementation mode of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0053] Please refer to Figures 1 to 7 Note that the diagrams provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0054] As Figure 1 shown, this embodiment provides an optical emission chip 1, and the optical emission chip 1 includes:

[0055] N groups of optical modulation channels, P optical input ports, and Q optical output ports, where M is a natural number greater than or equal to 1, and P and Q are natural numbers less than or equal to M.

[0056] As Figure 1As shown, the optical signal input ends of N groups of optical modulation channels are respectively connected to corresponding optical input ports, and the optical signal output ends of N groups of optical modulation channels are respectively connected to corresponding optical output ports.

[0057] Specifically, in this embodiment, N is set to 4, which are respectively denoted as the first optical modulation channel 2a, the second optical modulation channel 2b, the third optical modulation channel 2c, and the fourth optical modulation channel 2d. P is set to 1, and Q is set to 1. That is, the optical signal input ends of each optical modulation channel are connected to the same optical input port 3, and the optical signal output ends of each optical modulation channel are connected to the same optical output port 4. In actual use, the numbers of N, P, and Q can be set according to actual needs. Multiple optical modulation channels can share one optical input port and / or multiple optical modulation channels can share one optical output port, including but not limited to, 4 groups of optical modulation channels configured with 2 optical input ports and 3 optical output ports, which are not listed one by one here.

[0058] As Figure 1 shown, each optical modulation channel modulates the input optical signal.

[0059] Specifically, each group of optical modulation channels includes a radio frequency filter 21 and a traveling wave Mach-Zehnder modulator 22; the radio frequency filter 21 performs high-pass filtering on the received electrical signal; the optical signal input end of the traveling wave Mach-Zehnder modulator 22 receives the corresponding optical signal, and the electrical signal input end is connected to the output end of the radio frequency filter 21.

[0060] More specifically, the radio frequency filter 21 receives the electrical signal and provides the high-pass filtered electrical signal to the traveling wave Mach-Zehnder modulator 22. As Figure 1 shown, as an implementation manner of this embodiment, the optical modulation channel is set to a differential structure; then the radio frequency filter 21 includes a first filtering unit and a second filtering unit. The first filtering unit performs high-pass filtering on one path of the differential signal, and the second filtering unit performs high-pass filtering on the other path of the differential signal; of course, the radio frequency filter 21 can also be set to an entire filtering structure to filter the two differential signals at the same time, which is not limited to this embodiment. As Figure 2 shown, as another implementation manner of this embodiment, the optical modulation channel is set to a single-ended structure; then the radio frequency filter 21 only includes a first filtering unit, and the first filtering unit performs high-pass filtering on the electrical signal.

[0061] As Figure 3As shown, by way of example, each filtering unit includes an inductor L and a resistor R; one end of the inductor L serves as the input / output end of the corresponding filtering unit, and the other end is grounded via the resistor R. In actual use, any circuit structure that can achieve high-pass filtering is applicable to the present utility model, including but not limited to a passive high-pass filtering structure composed of one or more passive network elements (inductor, capacitor, resistor); each filtering unit can be configured with the same structure or different structures, which will not be elaborated one by one here.

[0062] More specifically, as Figure 4 and Figure 5 shown, the traveling-wave Mach-Zehnder modulator 22 receives an optical signal and modulates the optical signal based on the electrical signal provided by the radio frequency filter 21. In this embodiment, the traveling-wave Mach-Zehnder modulator 22 includes a Mach-Zehnder interference structure 221, a traveling-wave phase shifter 222, and a radio frequency terminal 223. The Mach-Zehnder interference structure 221 provides a propagation path for the optical signal. The traveling-wave phase shifter 222 acts on the waveguide arms of the Mach-Zehnder interference structure 221 to modulate the phase of the optical signal in the Mach-Zehnder interference structure 221. The radio frequency terminal 223 is connected to the output end of the traveling-wave phase shifter 222.

[0063] Among them, as Figure 4 and Figure 5As shown, the Mach-Zehnder interference structure 221 includes a beam splitter 22a, a first waveguide arm 22b, a second waveguide arm 22c, and a combiner 22d; the two waveguide arms are arranged side by side between the beam splitter 22a and the combiner 22d. As an example, the beam splitter 22a is implemented based on a beam splitting waveguide. The input end of the beam splitter 22a is a single waveguide, and the output end is divided into two waveguides, so as to achieve the purpose of splitting the input optical signal into two beams. In this embodiment, the beam splitter 22a is configured as a 50 / 50 beam splitting waveguide structure, that is, the two waveguides at the output end respectively obtain 50% of the input optical signal. The first ends of the first waveguide arm 22b and the second waveguide arm 22c are respectively connected to the two output ends of the beam splitter 22a, so that the two split beams of light are respectively transmitted and modulated in the corresponding waveguide arms; in this embodiment, the lengths of the two waveguide arms are equal to ensure that the propagation paths of the two split beams of optical signals are the same. The first waveguide arm 22b and the second waveguide arm 22c are disposed on a substrate, and each waveguide arm includes a P-doped region and an N-doped region to form a PN junction; as an example, the N-doped regions of the first waveguide arm 22b and the second waveguide arm 22c are adjacent to each other, and the P-doped regions are disposed on the outside. As an example, the combiner 22d is implemented based on a combining waveguide. The input end of the combiner 22d is two waveguides, and the output end is combined into a single waveguide. The two input ends are respectively connected to the second ends of the first waveguide arm 22b and the second waveguide arm 22c, so that the two beams of light output from the first waveguide arm 22b and the second waveguide arm 22c interfere in the combining region, and the interfering light is then output from the output end of the combiner 22d. In this embodiment, the combiner 22d is configured as a 50 / 50 combining waveguide structure, that is, the two waveguides at the input end respectively provide 50% of the optical signal for combining.

[0064] As Figure 1 shown, as an implementation manner of this embodiment, the optical modulation channel is set as a differential structure; then as Figure 4As shown in the figure, the traveling wave phase shifter 222 includes a first traveling wave electrode 22e (traveling wave electrodes, TWE), a second traveling wave electrode 22f, a first PN junction 22g on the first waveguide arm 22b, and a second PN junction 22h on the second waveguide arm 22c. The first traveling wave electrode 22e is electrically connected to the anode (or cathode) of the first PN junction 22g, forming a first phase shifter to modulate the optical signal in the first waveguide arm 22b. The second traveling wave electrode 22f is electrically connected to the anode (or cathode) of the second PN junction 22h, forming a second phase shifter to modulate the optical signal in the second waveguide arm 22c. The cathodes (or anodes) of the first PN junction 22g and the second PN junction 22h are connected together and connected to the corresponding common electrode Vbias; and both the first PN junction 22g and the second PN junction 22h are in the reverse bias state. In this example, each waveguide arm and each traveling wave electrode are arranged in parallel. The electrical signal processed by the first filtering unit in the RF filter 21 is loaded onto the first traveling wave electrode 22e, and the electrical signal processed by the second filtering unit in the RF filter 21 is loaded onto the second traveling wave electrode 22f. As Figure 2 shown, as another implementation manner of this embodiment, the optical modulation channel is set to a single-ended structure; then as Figure 5 shown, the structure of the traveling wave phase shifter 222 is the same as Figure 1 that, but both ends of the second traveling wave electrode 22f are grounded, that is, only the optical signal of the first waveguide arm 22b is modulated. The second traveling wave electrode 22f can also be directly removed, which will not be elaborated here one by one.

[0065] As Figure 1 、 2 、4, and 5 shown, the RF terminal 223 is used to absorb the electrical signal output by the traveling wave phase shifter 222. As Figure 1 shown, as an implementation manner of this embodiment, the optical modulation channel is set to a differential structure; then as Figure 4 shown, the RF terminal 223 includes a first terminal resistor RL1 and a second terminal resistor RL2. The first ends of the first terminal resistor RL1 and the second terminal resistor RL2 are respectively connected to the differential output terminals of the traveling wave phase shifter 222, and the second ends are connected together (connected to the same potential, or floating); as an example, the resistance values of the first terminal resistor RL1 and the second terminal resistor RL2 are the same, denoted as RL. Further, in another example, the second ends of the first terminal resistor RL1 and the second terminal resistor RL2 are also connected to the common mode voltage or grounded. As Figure 2 shown, as another implementation manner of this embodiment, the optical modulation channel is set to a single-ended structure; then as Figure 5As shown, the radio frequency terminal 223 only includes a first terminal resistor RL1. The first end of the first terminal resistor RL1 is connected to the output end of the traveling wave phase shifter 222, and the second end is connected to the common mode voltage or ground. In actual use, any structure that can be used as a radio frequency terminal to absorb the electrical signal output by the traveling wave phase shifter 222 is applicable to the present invention, including but not limited to a structure composed of one or more passive network elements (inductor, capacitor, resistor); this is not limited to this embodiment.

[0066] It should be noted that the traveling wave Mach-Zehnder modulator 22 in each optical modulation channel can be configured with the same structure or different structures, and is set according to actual needs.

[0067] As Figure 6 Shown is the differential circuit diagram of the optical modulation channel of this embodiment. The low-frequency signal in the differential electrical signal Vdiff is absorbed by the filtering unit in the radio frequency filter 21, and the high-frequency signal is coupled to the traveling wave phase shifter 22 through the filtering unit and finally absorbed by the terminal resistor. The optical signal enters two waveguide arms after being split. The traveling wave phase shifter 22 modulates the optical signals propagating in the two waveguide arms, so that the optical signals in the two waveguide arms generate opposite phase differences. When the optical signals propagating on the two waveguide arms are combined, the phase difference is converted into an intensity-modulated optical signal. The electrical signal of the present invention first passes through a passive radio frequency filter and then enters the traveling wave Mach-Zehnder modulator to convert the optical wave into a modulated optical signal. At this time, the bandwidth of the optical emission chip is jointly determined by the radio frequency filter and the traveling wave Mach-Zehnder modulator. The radio frequency filter performs low-frequency filtering or high-frequency enhancement on the input electrical signal, providing an additional means of bandwidth enhancement. Combined with a longer traveling wave phase shifter, the effect of optimizing the bandwidth and modulation efficiency of the optical emission chip at the same time is achieved.

[0068] As Figure 7 Shown, the solid line is the S21 parameter curve of the present invention, and the dotted line is the S21 parameter curve of the traditional structure; it can be seen that the radio frequency filter of the present invention provides additional design freedom. By using a high-pass filter, an additional means of chip bandwidth enhancement is provided. Combined with a longer traveling wave phase shifter, the high-frequency response can be increased while maintaining the low-frequency response, that is, the bandwidth is increased.

[0069] This embodiment also provides an optical device, which at least includes the optical emission chip 1 of this embodiment.

[0070] In summary, the present utility model provides an optical emission chip and an optical device, comprising: N groups of optical modulation channels, P optical input ports, and Q optical output ports, where M is a natural number greater than or equal to 1, and P and Q are natural numbers less than or equal to M; the optical signal input ends of the N groups of optical modulation channels are respectively connected to the corresponding optical input ports, and the optical signal output ends of the N groups of optical modulation channels are respectively connected to the corresponding optical output ports, and each optical modulation channel modulates the input optical signal; each group of optical modulation channels includes a radio frequency filter and a traveling wave Mach-Zehnder modulator; the radio frequency filter performs high-pass filtering on the received electrical signal; the optical signal input end of the traveling wave Mach-Zehnder modulator receives the corresponding optical signal, and the electrical signal input end is connected to the output end of the radio frequency filter. The optical emission chip and the optical device of the present utility model provide the electrical signal to the traveling wave Mach-Zehnder modulator after high-pass filtering, and adjust the frequency response of the optical emission chip through the radio frequency filter, thereby achieving the effect of simultaneously optimizing the bandwidth and modulation efficiency of the optical emission chip, and greatly improving the performance of the optical emission chip. Therefore, the present utility model effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0071] The above embodiments are only illustrative of the principles and effects of the present utility model, and are not used to limit the present utility model. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present utility model. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present utility model should still be covered by the claims of the present utility model.

Claims

1. A light-emitting chip, characterized in that, The optical emission chip at least includes: N groups of optical modulation channels, P optical input ports, and Q optical output ports, where M is a natural number greater than or equal to 1, and P and Q are natural numbers less than or equal to M; The optical signal input ends of the N groups of optical modulation channels are respectively connected to the corresponding optical input ports, and the optical signal output ends of the N groups of optical modulation channels are respectively connected to the corresponding optical output ports. Each optical modulation channel modulates the input optical signal; Each group of optical modulation channels includes a radio frequency filter and a traveling-wave Mach-Zehnder modulator; the radio frequency filter performs high-pass filtering on the received electrical signal; the optical signal input end of the traveling-wave Mach-Zehnder modulator receives the corresponding optical signal, and the electrical signal input end is connected to the output end of the radio frequency filter.

2. The optical emission chip according to claim 1, wherein: The optical modulation channel is of a differential structure.

3. The optical emission chip according to claim 2, characterized in that: The radio frequency filter includes a first filtering unit and a second filtering unit; the first filtering unit performs high-pass filtering on one path of the differential signal, and the second filtering unit performs high-pass filtering on the other path of the differential signal.

4. The optical emission chip according to claim 1, wherein: The optical modulation channel is of a single-ended structure.

5. The optical emission chip according to claim 4, characterized in that: The radio frequency filter includes a first filtering unit; the first filtering unit performs high-pass filtering on the electrical signal.

6. The optical emission chip according to claim 3 or 5, characterized in that: Each filtering unit is a passive high-pass filtering structure.

7. The optical emission chip according to claim 6, wherein: Each filtering unit includes an inductor and a resistor. One end of the inductor serves as the input / output end of the corresponding filtering unit, and the other end is grounded via the resistor.

8. The optical emission chip according to any one of claims 2-5, characterized in that: The traveling-wave Mach-Zehnder modulator includes a Mach-Zehnder interference structure, a traveling-wave phase shifter, and a radio frequency terminal; The traveling-wave phase shifter acts on the waveguide arms of the Mach-Zehnder interference structure to modulate the phase of the optical signal in the Mach-Zehnder interference structure; The radio frequency terminal is connected to the output end of the traveling-wave phase shifter.

9. An optical device, characterized in that, The optical device at least includes the optical emission chip according to any one of claims 1-8.

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