Arrayed waveguide grating, optical transmitter, optical receiver, and optical communication system

Abstract

An arrayed waveguide grating (50), an optical transmitter (20), an optical receiver (40), and an optical communication system (10) are provided. The arrayed waveguide grating (50) includes m first waveguides (501), a first coupler (502), k second waveguides (503), a second coupler (504), and n third waveguides (505), where m, n, and k are all positive integers, and the lengths of the k second waveguides (503) increase in order. The first waveguide (501) is configured to transmit a first optical signal to the first coupler (502). The first coupler (502) is configured to generate k second optical signals based on the first optical signal. The second waveguide (503) is configured to transmit the second optical signal to a first phase-shift structure (506). The first phase-shift structure (506) is configured to adjust the amplitude of one or more optical signals of different wavelengths in the second optical signal to generate a third optical signal. The second coupler (504) is configured to generate n fourth optical signals based on the third optical signal. The third waveguide (505) is configured to output the fourth optical signals. Further provided are an optical transmitter (20), an optical receiver (40), and an optical communication system (10) that include the arrayed-waveguide grating (50).

Description

[Technical Field]

[0001] TECHNICAL FIELD Embodiments of this application relate to the field of optical communication technology, and in particular to an arrayed waveguide grating, an optical transmitting device, an optical receiving device, and an optical communication system. [Background technology]

[0002] Optical communication systems are currently the mainstream communication system. Optical communication systems typically use wavelength division multiplexing (WDM) technology to transmit optical signals. By using WDM technology in the optical transmitter of an optical communication system, multiple optical signals of different wavelengths can be multiplexed and the multiplexed signal can be transmitted over a single optical fiber. The optical receiver of the optical communication system separates the optical signals of different wavelengths from the optical signal transmitted over a single optical fiber and sends the optical signal of the specified wavelength to a specified optical receiver to carry out communication. By using WDM technology, the communication capacity and communication speed of the optical communication system can be increased.

[0003] In optical communication systems using WDM technology, an arrayed waveguide grating (AWG) is disposed in an optical receiver to separate optical signals of different wavelengths within a single optical signal beam. The arrayed waveguide grating includes multiple waveguides configured to output optical signals. When the AWG separates optical signals of different wavelengths within a single optical signal beam, the insertion loss of one or more of the waveguides configured to output the optical signals in the AWG is high. Summary of the Invention

[0004] Embodiments of the present application provide an arrayed waveguide grating, an optical transmitter, an optical receiver, and an optical communication system that provide low insertion loss for one or more waveguides configured to output an optical signal in the arrayed waveguide grating.

[0005] According to a first aspect, there is provided an arrayed waveguide grating. The arrayed waveguide grating includes m first waveguides, a first coupler, k second waveguides, a second coupler, and n third waveguides. The first coupler is connected between the first waveguide and the second waveguide. The second coupler is connected between the second waveguide and the third waveguide. m, n, and k are all positive integers. The lengths of the k second waveguides increase in order. The difference between the lengths of two adjacent second waveguides is a fixed value. A first phase shift structure is further disposed between the second waveguide and the second coupler. The first waveguide is configured to transmit a first optical signal to the first coupler. The first coupler is configured to receive a first optical signal transmitted by the first waveguide, generate k second optical signals based on the first optical signal, and couple one second optical signal to one second waveguide for transmission. The second waveguide is configured to transmit the second optical signal to the first phase shift structure. The first phase shift structure is configured to adjust the amplitude of one or more optical signals of different wavelengths in the second optical signal to generate a third optical signal. The second coupler is configured to receive the third optical signal generated by the first phase shift structure, generate n fourth optical signals based on the third optical signal, and couple one fourth optical signal to one third waveguide for transmission. The third waveguide is configured to output the fourth optical signal. In the arrayed waveguide grating, the first waveguide is configured to transmit the first optical signal to the first coupler. For example, the first optical signal includes an optical signal of wavelength λ1, an optical signal of wavelength λ2, and an optical signal of wavelength λ3. The first coupler generates k second optical signals based on the first optical signal and couples one second optical signal to one second waveguide for transmission. The second optical signals also include an optical signal with wavelength λ1, an optical signal with wavelength λ2, and an optical signal with wavelength λ3. The second waveguide is configured to transmit the second optical signals to the first phase shift structure. The first phase shift structure is configured to change the amplitude of the optical signals of one or more wavelengths in the second optical signal to generate a third optical signal. For example, the relationship between the divergence field distribution and the divergence angle of the second optical signal is Gaussian, with the amplitude smoothly decreasing from the center to the outside.For example, the amplitude of the optical signal of wavelength λ1 in the second optical signal and the amplitude of the optical signal of wavelength λ3 in the second optical signal are small, and the amplitude of the optical signal of wavelength λ2 (center wavelength) in the second optical signal is large. The first phase shift structure can change the amplitude of the optical signal of wavelength λ1 in the second optical signal and the amplitude of the optical signal of wavelength λ3 in the second optical signal to generate a third optical signal. The amplitude of the optical signal of wavelength λ1 in the third optical signal is larger than the amplitude of the optical signal of wavelength λ1 in the second optical signal. The amplitude of the optical signal of wavelength λ3 in the third optical signal is larger than the amplitude of the optical signal of wavelength λ3 in the second optical signal. The first phase shift structure transmits the third optical signal to the second coupler. The second coupler generates n fourth optical signals based on the third optical signal. For example, the n fourth optical signals include one fourth optical signal of wavelength λ1, one fourth optical signal of wavelength λ2, and one fourth optical signal of wavelength λ3. The second coupler couples a fourth optical signal to a second waveguide for transmission. The second waveguide outputs a fourth optical signal. The optical intensity of the fourth optical signal output by the third waveguide is positively correlated with the square of the amplitude of the fourth optical signal output by the third waveguide. The optical intensity of the fourth optical signal output by the third waveguide is negatively correlated with the insertion loss of the third waveguide. When the amplitude of the optical signal with wavelength λ1 in the third optical signal is greater than the amplitude of the optical signal with wavelength λ1 in the second optical signal, the amplitude of the fourth optical signal with wavelength λ1 generated based on the third optical signal increases. Therefore, the insertion loss of the third waveguide outputting the fourth optical signal with wavelength λ1 decreases. When the amplitude of the optical signal with wavelength λ3 in the third optical signal is greater than the amplitude of the optical signal with wavelength λ3 in the second optical signal, the amplitude of the fourth optical signal with wavelength λ3 generated based on the third optical signal increases. Therefore, the insertion loss of the third waveguide outputting the fourth optical signal with wavelength λ3 decreases.

[0006] Optionally, a second phase shift structure is further disposed between the first waveguide and the first coupler. The first waveguide is specifically configured to transmit the first optical signal to the second phase shift structure. The second phase shift structure is configured to adjust the amplitude of the optical signal of one or more wavelengths in the first optical signal to generate a fifth optical signal. The first coupler is specifically configured to receive the fifth optical signal generated by the second phase shift structure, generate k second optical signals based on the fifth optical signal, and couple one second optical signal to one second waveguide for transmission. In this optional solution, when a second phase shift structure is further disposed between the first waveguide and the first coupler, the second phase shift structure can change the amplitude of the optical signal of one or more wavelengths in the first optical signal to generate the fifth optical signal. For example, if the relationship between the divergence field distribution and the divergence angle of the fifth optical signal is a flat-top distribution, the relationship between the divergence field distribution and the divergence angle of the second optical signal generated by the first coupler based on the fifth optical signal will also be a flat-top distribution, so that the insertion loss of the waveguide 505 of the arrayed-waveguide grating 50 is further reduced.

[0007] Optionally, the divergence angle of the third optical signal is equal to a corresponding central angle on a Rowland circle of the arc between the first tertiary waveguide and the nth tertiary waveguide. In this optional manner, the first phase shift structure can further adjust the divergence angle of the third optical signal. When the divergence angle of the third optical signal generated by the first phase shift structure is equal to a corresponding central angle on a Rowland circle of the arc between the first tertiary waveguide and the nth tertiary waveguide, when the third optical signal is freely transmitted from the second coupler to the nth tertiary waveguides, the third optical signal has no energy distributed in areas other than the nth tertiary waveguides, and therefore, the device insertion loss of the arrayed-waveguide grating can be increased.

[0008] Optionally, the first phase shift structure is disposed within the second coupler. In this optional solution, the first phase shift structure is disposed within the second coupler, thus reducing the manufacturing process of the first phase shift structure and simplifying the manufacturing process of the first phase shift structure.

[0009] Optionally, the second phase shift structure is disposed within the first coupler. In this optional solution, the second phase shift structure is disposed within the first coupler, thus reducing the manufacturing process of the second phase shift structure and simplifying the manufacturing process of the second phase shift structure.

[0010] Optionally, the first phase shift structure includes any one of a Powell prism, a metalens, and a liquid crystal lens. In this optional manner, the Powell prism may enable the amplitudes of optical signals of one or more wavelengths in the optical signal output by the Powell prism to be the same. For example, the relationship between the divergence field distribution and the divergence angle of the optical signal output by the Powell prism is a flat-top distribution, and the divergence angles of the optical signals output by the Powell prism can be set to be different. A predetermined divergence angle can be obtained by adjusting the size of the Powell prism. The metalens may enable the amplitudes of optical signals of one or more wavelengths in the optical signal output by the metalens to be the same. For example, the relationship between the divergence field distribution and the divergence angle of the optical signal output by the metalens is a flat-top distribution, and the divergence angles of the optical signals output by the metalens can be set to be different. A predetermined divergence angle can be obtained by adjusting the size of the metalens. The liquid crystal lens may enable the amplitudes of optical signals of one or more wavelengths in the optical signal output by the liquid crystal lens to be the same. For example, the relationship between the divergence field distribution and divergence angle of the optical signal output by the metalens is a flat-top distribution, while the divergence angle of the optical signal output by the liquid crystal lens can be set to be different by adjusting the voltage values ​​in different regions of the liquid crystal lens to obtain a desired divergence angle.

[0011] Optionally, the second phase shift structure includes any one of a Powell prism, a metalens, and a liquid crystal lens. In this optional manner, the Powell prism may enable the amplitudes of optical signals of one or more wavelengths in the optical signal output by the Powell prism to be the same. For example, the relationship between the divergence field distribution and the divergence angle of the optical signal output by the Powell prism is a flat-top distribution, and the divergence angles of the optical signals output by the Powell prism can be set to be different. A predetermined divergence angle can be obtained by adjusting the size of the Powell prism. The metalens may enable the amplitudes of optical signals of one or more wavelengths in the optical signal output by the metalens to be the same. For example, the relationship between the divergence field distribution and the divergence angle of the optical signal output by the metalens is a flat-top distribution, and the divergence angles of the optical signals output by the metalens can be set to be different. A predetermined divergence angle can be obtained by adjusting the size of the metalens. The liquid crystal lens may enable the amplitudes of optical signals of one or more wavelengths in the optical signal output by the liquid crystal lens to be the same. For example, the relationship between the divergence field distribution and divergence angle of the optical signal output by the metalens is a flat-top distribution, while the divergence angle of the optical signal output by the liquid crystal lens can be set to be different by adjusting the voltage values ​​in different regions of the liquid crystal lens to obtain a desired divergence angle.

[0012] Optionally, the difference between the amplitudes of any two optical signals of different wavelengths in the plurality of optical signals of different wavelengths in the third optical signal is smaller than a predetermined value. For example, in this optional manner, if the difference between the amplitudes of any two optical signals of different wavelengths in the plurality of optical signals of different wavelengths in the third optical signal is smaller than a predetermined value, it indicates that the amplitudes of the plurality of optical signals of different wavelengths in the third optical signal are approximately equal. In this case, the relationship between the divergence field distribution and the divergence angle of the third optical signal is a flat-top distribution.

[0013] Optionally, the arrayed waveguide grating further comprises a substrate on which the m first waveguides, the first coupler, the k second waveguides, the first phase-shift structure, the second coupler, and the n third waveguides are fabricated.

[0014] According to a second aspect, there is provided an optical transmission device. The optical transmission device includes a light source, s optical modulators, and an arrayed-waveguide grating according to any one of the first aspects. One of the s optical modulators connects the light source to one first waveguide of the arrayed-waveguide grating. s is equal to or less than m. m is greater than n.

[0015] According to a third aspect, there is provided an optical transmission device. The optical transmission device includes s light sources, s optical modulators, and an arrayed-waveguide grating according to any one of the first aspects. One of the s optical modulators connects one of the s light sources to one first waveguide of the arrayed-waveguide grating. s is equal to or less than m. m is greater than n.

[0016] According to a fourth aspect, there is provided an optical receiving device. The optical receiving device includes an arrayed-waveguide grating according to any one of the first aspects and s optical receivers. One third waveguide of the arrayed-waveguide grating is connected to one optical receiver. s is equal to or less than n. m is smaller than n.

[0017] According to a fifth aspect, there is provided an optical communication system including an optical transmitter according to the second or third aspect, an optical receiver according to the fourth aspect, and an optical fiber connecting the optical transmitter and the optical receiver.

[0018] For technical effects achieved by any of the possible implementations of the second to fifth aspects, please refer to the technical effects achieved by any of the various implementations of the first aspect, and the details will not be described again here. [Brief explanation of the drawings]

[0019] [Figure 1]1 is a diagram of a configuration of an optical communication system according to one embodiment of the present application. [Figure 2] 1 is a diagram of the configuration of an optical transmitting device according to an embodiment of the present application; [Figure 3] FIG. 10 is a diagram illustrating the configuration of an optical transmitting device according to another embodiment of the present application. [Figure 4] 1 is a diagram of the configuration of an optical receiving device according to an embodiment of the present application; [Figure 5] FIG. 1 is a diagram of an arrayed waveguide grating configuration according to one embodiment of the present application. [Figure 6] FIG. 1 is a diagram of the output spectrum of an arrayed waveguide grating according to an embodiment of the present application. [Figure 7] FIG. 10 is a diagram of an arrayed waveguide grating configuration according to another embodiment of the present application. [Figure 8] FIG. 10 is a diagram of a configuration of a coupler in an arrayed waveguide grating according to another embodiment of the present application. [Figure 9] FIG. 2 is a first diagram of a diverging field of an optical signal according to another embodiment of the present application; [Figure 10] FIG. 10 is a second diagram of the divergence field of an optical signal according to another embodiment of the present application. [Figure 11] FIG. 10 is another diagram of a configuration of a coupler in an arrayed waveguide grating according to another embodiment of the present application. [Figure 12] FIG. 2 is a first diagram of interference of an optical signal according to another embodiment of the present application. [Figure 13] FIG. 10 is a second diagram of interference of an optical signal according to another embodiment of the present application. [Figure 14] FIG. 10 is a diagram of an arrayed waveguide grating configuration according to yet another embodiment of the present application. [Figure 15] FIG. 10 is a diagram of a configuration of a coupler in an arrayed waveguide grating according to yet another embodiment of the present application. [Figure 16] FIG. 10 is a diagram of an arrayed waveguide grating configuration according to yet another embodiment of the present application. [Figure 17]FIG. 10 is a diagram of the output spectrum of an arrayed waveguide grating according to yet another embodiment of the present application. [Figure 18] FIG. 10 is a diagram of an arrayed waveguide grating configuration according to another embodiment of the present application. [Figure 19] FIG. 10 is a diagram of a material layer configuration of an arrayed waveguide grating according to yet another embodiment of the present application. [Figure 20] FIG. 10 is a diagram of a configuration of a phase shift structure in an arrayed waveguide grating according to yet another embodiment of the present application. [Figure 21] FIG. 10 is a diagram of a configuration of a phase shift structure in an arrayed waveguide grating according to another embodiment of the present application. [Figure 22] FIG. 10 is a first diagram of a configuration of material layers of a phase-shifting structure in an arrayed waveguide grating according to another embodiment of the present application. [Figure 23] FIG. 10 is a second diagram of a configuration of material layers of a phase-shifting structure in an arrayed waveguide grating according to another embodiment of the present application. [Figure 24] FIG. 10 is a principle diagram of a phase shift structure in an arrayed waveguide grating according to another embodiment of the present application. [Figure 25] FIG. 10 is a diagram of a configuration of a phase shift structure in an arrayed waveguide grating according to yet another embodiment of the present application. [Figure 26] FIG. 10 is a diagram of a configuration of a phase shift structure in an arrayed waveguide grating according to yet another embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, the technical solutions in the embodiments of this application will be described with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only some but not all of the embodiments of this application.

[0021] Unless otherwise defined, all technical terms used herein have the same meanings as commonly known to those skilled in the art. In the embodiments of this application, "at least one" means one or more, and "plurality" means two or more. "And / or" describes an association relationship between related objects and indicates that three relationships may exist. For example, A and / or B can represent the following cases: only A is present, both A and B are present, and only B is present, where A and B may be singular or plural. The character " / " generally indicates an "or" relationship between related objects. "At least one of the following items" or similar expressions refers to a single item or any combination of items, including any combination of multiple items. For example, at least one item of a, b, or c can represent a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c may be singular or plural. Furthermore, in the embodiments of this application, terms such as "first" and "second" do not limit the quantity or order of execution.

[0022] Furthermore, in the embodiments of this application, position terms such as "top" and "bottom" are defined with respect to the positions of components in the accompanying drawings. It should be understood that these directional terms are relative concepts used for relative description and clarity, and may change corresponding to the positions of components in the accompanying drawings.

[0023] In the embodiments of this application, terms such as "example" or "for example" are used to indicate providing an example, illustration, or explanation. Any embodiment or design scheme described in the embodiments of this application as an "example" or "for example" should not be construed as being preferred or having more advantages than other embodiments or design schemes. Rather, the use of terms such as "example" or "for example" is intended to concretely present a relative concept.

[0024] Hereinafter, the technical solutions in the embodiments of this application will be described with reference to the accompanying drawings.

[0025] Please refer to FIG. 1. One embodiment of this application provides a diagram of the configuration of an optical communication system 10. The optical communication system 10 uses wavelength division multiplexing (WDM) technology to transmit optical signals. WDM technology is a technology in which optical signals of different wavelengths are multiplexed and transmitted through the same optical fiber. WDM technology continuously increases the communication capacity and communication speed of the optical communication system 10. The optical communication system 10 includes an optical transmitter 20, an optical fiber 30, and an optical receiver 40. The optical transmitter 20 is configured to generate modulated optical signals of multiple wavelengths, multiplex the modulated optical signals of the multiple wavelengths into a multiplexed optical signal, and transmit the multiplexed optical signal to the optical receiver 40 via the optical fiber 30. The optical receiver 40 is configured to receive the multiplexed optical signal transmitted through the optical fiber 30, separate the modulated optical signals of different wavelengths from the multiplexed optical signal, and send the modulated optical signal of a predetermined wavelength to a predetermined optical receiver.

[0026] For example, the optical communication system 10 further includes an optical amplifier and an optical add / drop multiplexer (OADM). The optical amplifier is disposed between two optical fibers. The optical amplifier is configured to amplify an optical signal transmitted in an optical fiber connected to an input end of the optical amplifier and output the amplified optical signal through an optical fiber connected to an output end of the optical amplifier. The optical add / drop multiplexer is disposed in the optical signal transmission path and configured to perform wavelength adding (add wave) and wavelength dropping (down wave) of one or more optical signals of wavelengths in the optical communication system, while also ensuring non-blocking passage of optical signals of other wavelengths. The optical communication system is not limited to this embodiment of this application.

[0027] For example, see FIG. 2. One embodiment of this application provides a diagram of the configuration of an optical transmission device. The optical transmission device 20 includes one light source 201, multiple optical modulators 202, and an arrayed waveguide grating (AWG) 203. The arrayed waveguide grating 203 includes multiple waveguides configured to receive optical signals and one waveguide configured to output an optical signal. One optical modulator 202 connects the light source 201 to one waveguide in the arrayed waveguide grating 203 configured to receive the optical signal. The waveguide in the arrayed waveguide grating 203 configured to output the optical signal is connected to an optical fiber 30. The light source 201 is configured to emit carrier optical signals of different wavelengths and transmit the carrier optical signals of different wavelengths to different optical modulators 202. The optical modulator 202 is configured to receive a carrier optical signal and a transmission signal of a predetermined wavelength, modulate the transmission signal onto the carrier optical signal of the predetermined wavelength to generate a modulated optical signal of the predetermined wavelength, and transmit the modulated optical signal of the predetermined wavelength to the arrayed waveguide grating 203. The arrayed waveguide grating 203 is configured to receive modulated optical signals of different wavelengths generated by the plurality of optical modulators 202, multiplex the modulated optical signals of different wavelengths to generate a multiplexed optical signal, and transmit the multiplexed optical signal to the optical receiving device 40 via the optical fiber 30.

[0028] For example, in FIG. 2, three optical modulators 202 are used as an example for explanation. The light source 201 is configured to generate carrier optical signals of three wavelengths. The three wavelengths are a carrier optical signal of wavelength λ1, a carrier optical signal of wavelength λ2, and a carrier optical signal of wavelength λ3, respectively. The light source 201 transmits the carrier optical signal of wavelength λ1 to a first optical modulator 202. The first optical modulator 202 is configured to receive the carrier optical signal of wavelength λ1 and transmission signal 1, and modulate the transmission signal 1 onto the carrier optical signal of wavelength λ1 to generate a modulated optical signal of wavelength λ1. The light source 201 transmits the carrier optical signal of wavelength λ2 to a second optical modulator 202. The second optical modulator 202 is configured to receive the carrier optical signal of wavelength λ2 and transmission signal 2, and modulate the transmission signal 2 onto the carrier optical signal of wavelength λ2 to generate a modulated optical signal of wavelength λ2. The light source 201 transmits a carrier optical signal of wavelength λ3 to the third optical modulator 202. The third optical modulator 202 is configured to receive the carrier optical signal of wavelength λ3 and the transmission signal 3, and modulate the transmission signal 3 onto the carrier optical signal of wavelength λ3 to generate a modulated optical signal of wavelength λ3. The arrayed waveguide grating 203 is configured to receive the modulated optical signal of wavelength λ1, the modulated optical signal of wavelength λ2, and the modulated optical signal of wavelength λ3, multiplex the modulated optical signal of wavelength λ1, the modulated optical signal of wavelength λ2, and the modulated optical signal of wavelength λ3 into a multiplexed optical signal, and transmit the multiplexed optical signal to the optical receiving device 40 via the optical fiber 30.

[0029] In some other embodiments, see FIG. 3. One embodiment of this application provides a diagram of the configuration of an optical transmitting device. The optical transmitting device 20 includes multiple light sources 201, multiple optical modulators 202, and an arrayed waveguide grating (AWG) 203. The arrayed waveguide grating 203 includes multiple waveguides configured to receive optical signals and one waveguide configured to output an optical signal. One optical modulator 202 connects one light source 201 to one waveguide in the arrayed waveguide grating 203 configured to receive the optical signal. The waveguide in the arrayed waveguide grating 203 configured to output the optical signal is connected to an optical fiber 30. The light source 201 is configured to emit a carrier optical signal of a predetermined wavelength and transmit the carrier optical signal of the predetermined wavelength to a predetermined optical modulator 202. The optical modulator 202 is configured to receive a carrier optical signal and a transmission signal of a predetermined wavelength, modulate the transmission signal onto the carrier optical signal of the predetermined wavelength to generate a modulated optical signal of the predetermined wavelength, and transmit the modulated optical signal of the predetermined wavelength to the arrayed waveguide grating 203. The arrayed waveguide grating 203 is configured to receive modulated optical signals of different wavelengths generated by the plurality of optical modulators 202, multiplex the modulated optical signals of different wavelengths to generate a multiplexed optical signal, and transmit the multiplexed optical signal to the optical receiving device 40 via the optical fiber 30.

[0030] For example, in FIG. 3 , three light sources 201 and three optical modulators 202 are used as an example for explanation. The first light source 201 is configured to generate a carrier optical signal of wavelength λ1 and transmit the carrier optical signal of wavelength λ1 to the first optical modulator 202. The first optical modulator 202 is configured to receive the carrier optical signal of wavelength λ1 and transmission signal 1 and modulate the transmission signal 1 onto the carrier optical signal of wavelength λ1 to generate a modulated optical signal of wavelength λ1. The second light source 201 is configured to generate a carrier optical signal of wavelength λ2 and transmit the carrier optical signal of wavelength λ2 to the second optical modulator 202. The second optical modulator 202 is configured to receive the carrier optical signal of wavelength λ2 and transmission signal 2 and modulate the transmission signal 2 onto the carrier optical signal of wavelength λ2 to generate a modulated optical signal of wavelength λ2. The third light source 201 is configured to generate a carrier optical signal of wavelength λ3 and transmit the carrier optical signal of wavelength λ3 to the third optical modulator 202. The third optical modulator 202 is configured to receive a carrier optical signal of wavelength λ3 and a transmission signal 3, and modulate the transmission signal 3 onto the carrier optical signal of wavelength λ3 to generate a modulated optical signal of wavelength λ3. The arrayed waveguide grating 203 is configured to receive the modulated optical signal of wavelength λ1, the modulated optical signal of wavelength λ2, and the modulated optical signal of wavelength λ3, multiplex the modulated optical signal of wavelength λ1, the modulated optical signal of wavelength λ2, and the modulated optical signal of wavelength λ3 into a multiplexed optical signal, and transmit the multiplexed optical signal to the optical receiving device 40 via the optical fiber 30.

[0031] For example, the optical transmission device 20 shown in Fig. 2 or 3 may further include an optical transmitter. The optical transmitter is configured to generate a transmission signal. The optical transmission device 20 is not limited to this embodiment of this application.

[0032] The multiplexed optical signal generated by the optical transmitting device 20 is transmitted to the optical receiving device 40 via the optical fiber 30. Please refer to FIG. 4. One embodiment of this application provides a diagram of the configuration of the optical receiving device 40. The optical receiving device 40 includes an arrayed waveguide grating (AWG) 401 and multiple optical receivers 402. The arrayed waveguide grating 401 includes one waveguide configured to receive an optical signal and multiple waveguides configured to output optical signals. One optical receiver 402 is connected to one waveguide in the arrayed waveguide grating 401 configured to output an optical signal. The waveguide in the arrayed waveguide grating 401 configured to receive the optical signal is connected to the optical fiber 30. The arrayed waveguide grating 401 is configured to receive the multiplexed optical signal transmitted through the optical fiber 30, separate modulated optical signals of different wavelengths from the multiplexed optical signal, and transmit the modulated optical signal of a predetermined wavelength to a predetermined optical receiver 402. The optical receiver 402 is configured to receive a modulated optical signal of a predetermined wavelength, obtain a transmission signal based on the modulated optical signal of the predetermined wavelength, and perform communication.

[0033] For example, in FIG. 4, three optical receivers 402 are used as an example for explanation. For example, if a multiplexed optical signal includes a modulated optical signal of wavelength λ1, a modulated optical signal of wavelength λ2, and a modulated optical signal of wavelength λ3, the arrayed waveguide grating 401 receives the multiplexed optical signal transmitted through the optical fiber 30, demultiplexes the multiplexed optical signal to generate modulated optical signals of different wavelengths, and transmits the modulated optical signal of wavelength λ1 to the first optical receiver 402. The first optical receiver 402 receives the modulated optical signal of wavelength λ1 and obtains transmission signal 1 from the modulated optical signal of wavelength λ1. The arrayed waveguide grating 401 transmits the modulated optical signal of wavelength λ2 to the second optical receiver 402. The second optical receiver 402 receives the modulated optical signal of wavelength λ2 and obtains transmission signal 2 from the modulated optical signal of wavelength λ2. The arrayed waveguide grating 401 transmits the modulated optical signal of wavelength λ3 to the third optical receiver 402. The third optical receiver 402 receives the modulated optical signal with wavelength λ3 and obtains the transmission signal 3 from the modulated optical signal with wavelength λ3.

[0034] For example, the optical receiving device 40 shown in Fig. 4 may further include an optical demodulator. The optical demodulator is connected between one optical receiver and one waveguide configured to output an optical signal in the arrayed-waveguide grating 401. The optical demodulator generates a received signal based on the optical signal output by the waveguide configured to output the optical signal in the arrayed-waveguide grating 401, and transmits the received signal to the optical receiver. The optical receiving device 40 is not limited to this embodiment of the present application.

[0035] For example, see FIG. 5. One embodiment of this application provides a diagram of the configuration of an arrayed waveguide grating. Referring to FIG. 5, the arrayed waveguide grating 50 includes m waveguides 501, a coupler 502, k waveguides 503, a coupler 504, and n waveguides 505. The coupler 502 is connected between the waveguide 501 and the waveguide 503. The coupler 504 is connected between the waveguide 503 and the waveguide 505. m, n, and k are all positive integers. The lengths of the k waveguides 503 increase sequentially. For example, based on the arrangement position of the arrayed waveguide grating 50 shown in FIG. 5, the lengths of the k waveguides 503 increase sequentially from bottom to top, and the difference between the length values ​​of two adjacent waveguides 503 within the k waveguides 503 is a fixed value. For example, the length values ​​of the k waveguides 503 form an arithmetic progression.

[0036] For example, when the arrayed-waveguide grating 50 is used in the optical receiving device 40, the arrayed-waveguide grating 50 is specifically the arrayed-waveguide grating 401 shown in FIG. 4 (see FIG. 5). An example in which the arrayed-waveguide grating 50 includes one waveguide 501, eleven waveguides 503, and three waveguides 505 is used for explanation. For example, the waveguide 501 in the arrayed-waveguide grating 50 is connected to the optical fiber 30 shown in FIG. 1. The waveguide 501 is configured to receive a multiplexed optical signal transmitted through the optical fiber 30. The multiplexed optical signal includes four modulated optical signals with different wavelengths. The waveguide 501 is further configured to input the multiplexed optical signal into a coupler 502. The multiplexed optical signal is freely transmitted within the coupler 502. The coupler 502 is configured to equally couple the multiplexed optical signal to eleven waveguides 503 and transmit the combined multiplexed optical signal to the coupler 504 via the eleven waveguides 503. The combined multiplexed optical signal is freely transmitted within the coupler 504 and output through a waveguide 505. After transmitting through the waveguides 503 and the coupler 504, modulated optical signals of different wavelengths in the multiplexed optical signal are focused onto one predetermined waveguide 505 and output through the waveguide 505. One of the three waveguides 503 is connected to one optical receiver 402 shown in FIG. 4. The arrayed-waveguide grating 50 separates the multiple modulated optical signals of different wavelengths in the multiplexed optical signal.

[0037] For example, see FIG. 5. When an optical signal transmitted to coupler 504 by any one of waveguides 503 is freely transmitted within coupler 504, the relationship between the divergence field distribution and the divergence angle of the optical signal is a Gaussian distribution, and the optical signal transmitted to coupler 504 by any one of waveguides 503 is located at the position of three waveguides 505. The amplitude peak is located at the center of the three waveguides 505, and the amplitude of the optical signal, which has a Gaussian distribution, decreases smoothly from the center to the outside. See FIG. 6. The three waveguides 505 output an optical signal of wavelength λ1, an optical signal of wavelength λ2, and an optical signal of wavelength λ3, respectively. The amplitude in waveguide 505 outputting the optical signal of wavelength λ2 is a first value, the amplitude in waveguide 505 outputting the optical signal of wavelength λ1 is a second value, and the amplitude in waveguide 505 outputting the optical signal of wavelength λ3 is also a second value. The first value is greater than the second value, and the optical intensity of the optical signal output by one waveguide 505 is positively correlated with the square of the amplitude of the optical signal output by the waveguide 505. Therefore, the optical intensity of the optical signal output by the waveguide 505 outputting the optical signal of wavelength λ2 is high, the optical intensity of the optical signal output by the waveguide 505 outputting the optical signal of wavelength λ1 is low, and the optical intensity of the optical signal output by the waveguide 505 outputting the optical signal of wavelength λ3 is low. The optical intensity of the optical signal output by one waveguide 505 is negatively correlated with the insertion loss (also called insertion loss) of the waveguide 505. Therefore, the insertion loss of the waveguide 505 outputting the optical signal of wavelength λ1 is large, and the insertion loss of the waveguide 505 outputting the optical signal of wavelength λ3 is large.

[0038] To reduce the insertion loss of a waveguide configured to output an optical signal in an arrayed waveguide grating, see FIG. 7. One embodiment of this application provides an arrayed waveguide grating. The arrayed waveguide grating includes m waveguides 501, a coupler 502, k waveguides 503, a coupler 504, and n waveguides 505. The coupler 502 is connected between the waveguide 501 and the waveguide 503. The coupler 504 is connected between the waveguide 503 and the waveguide 505. m, n, and k are all positive integers. The lengths of the k waveguides 503 increase sequentially. For example, based on the arrangement position of the arrayed waveguide grating 50 shown in FIG. 7, the lengths of the k waveguides 503 increase sequentially from bottom to top, the difference between the lengths of two adjacent waveguides 503 is a fixed value, and the length values ​​of the k waveguides 503 form an arithmetic progression.

[0039] A phase shift structure 506 is further disposed between the waveguide 503 and the coupler 504. For example, specifically, one phase shift structure 506 is disposed between each waveguide 503 and the coupler 504. See FIG. 7 . An example in which the arrayed-waveguide grating 50 includes one waveguide 501, eleven waveguides 503, and three waveguides 505 is used for explanation. Such an arrayed-waveguide grating 50 is configured to implement the function of separating optical signals of different wavelengths in a multiplexed optical signal. Specifically, the arrayed-waveguide grating 50 is the arrayed-waveguide grating 401 in the optical receiving device 40 shown in FIG. 4 . The waveguide 501 in the arrayed-waveguide grating 50 shown in FIG. 7 is connected to the optical fiber 30 shown in FIG. 1 . One waveguide 505 in the arrayed-waveguide grating 50 shown in FIG. 7 is connected to one optical receiver 402 shown in FIG. 4 . When the arrayed waveguide grating 50 is disposed in an optical receiving device, the arrayed waveguide grating 50 may include m waveguides 501, k waveguides 503, and n waveguides 505, and the optical receiving device includes s optical receivers, where m is greater than n and s is less than or equal to n.

[0040] Waveguide 501 is configured to transmit a first optical signal to coupler 502. For example, the first optical signal may be a multiplexed optical signal transmitted to optical receiving device 40 by optical fiber 30. In this case, the first optical signal includes an optical signal with wavelength λ1, an optical signal with wavelength λ2, and an optical signal with wavelength λ3.

[0041] The coupler 502 is configured to receive a first optical signal transmitted by the waveguide 501, generate eleven second optical signals based on the first optical signal, and couple one second optical signal to one waveguide 503 for transmission. Specifically, see FIG. 8. One embodiment of this application provides a diagram of the configuration of the coupler 502. The output end of the waveguide 501 is arranged on the circumference of the Rowland circle of the coupler 502, and the input ends of the eleven waveguides 503 are arranged on a diffraction grating circle having a radius twice the radius of the Rowland circle. The first optical signal transmitted from the output end of the waveguide 501 to the coupler 502 by the waveguide 501 is freely transmitted within the coupler 502. The coupler 502 generates eleven second optical signals based on the first optical signal. Specifically, the eleven second optical signals have equal power, and each second optical signal includes an optical signal with wavelength λ1, an optical signal with wavelength λ2, and an optical signal with wavelength λ3. Coupler 502 couples one second optical signal to one waveguide 503 for transmission.

[0042] When the optical signal of wavelength λ1 in the first optical signal is freely transmitted within coupler 502 to any one of eleven waveguides 503, the optical path is consistent and the phase is consistent. i =φ (λ1-1) It is written as Φ iis the phase of an optical signal of wavelength λ1 in the second optical signal received by the i-th waveguide 503 among the eleven waveguides 503, where i=[-5,-4,-3,-2,-1,0,1,2,3,4,5]. For example, based on the arrangement of the arrayed waveguide 50 shown in FIG. 5, the eleven waveguides 503 are, from bottom to top, the (-5)-th waveguide 503, the (-4)-th waveguide 503, the (-3)-th waveguide 503, . . . , the i-th waveguide 503, . . . , the 5-th waveguide. Based on the formula, it can be seen that the starting phase of any optical signal of wavelength λ1 in the second optical signal transmitted to the waveguide 503 is φ (λ1-1) When the optical signal of wavelength λ2 in the first optical signal is freely transmitted in the coupler 502 to any one of the eleven waveguides 503, the optical path is consistent and the phase is consistent. i =φ (λ2-1) It is written as Φ i is the phase of an optical signal of wavelength λ2 in the second optical signal received by the i-th waveguide 503 of the eleven waveguides 503, where i=[-5,-4,-3,-2,-1,0,1,2,3,4,5]. Therefore, the starting phase of any optical signal of wavelength λ2 in the second optical signal transmitted to a waveguide 503 is φ (λ2-1) When the optical signal of wavelength λ3 in the first optical signal is freely transmitted in the coupler 502 to any one of the eleven waveguides 503, the optical path is consistent and the phase is consistent. i =φ (λ3-1) It is written as Φ i is the phase of the optical signal of wavelength λ3 in the second optical signal received by the i-th waveguide 503 of the eleven waveguides 503, where i=[-5,-4,-3,-2,-1,0,1,2,3,4,5]. Therefore, the starting phase of any optical signal of wavelength λ3 in the second optical signal transmitted to the waveguide 503 is φ (λ3-1) is.

[0043] The waveguides 503 are configured to transmit the second optical signal to the phase-shift structure 506. For example, the lengths of the eleven waveguides 503 increase in order from bottom to top, the difference between the lengths of two adjacent waveguides 503 is a fixed value, and the length values ​​of the eleven waveguides 503 form an arithmetic progression. Therefore, the optical signal of wavelength λ1 in the second optical signal is transmitted through multiple different optical paths in the eleven waveguides 503, and the phase of the optical signal of wavelength λ1 in the second optical signal output by any one of the eleven waveguides 503 is also different. Equation n s ΔL=mλ1-n s Δl1 and formula Φ i =φ (λ1-1) +φ (λ1-2) +i*(2mπ-Δφ (λ1-1) ) See n s is the refractive index of the material of the waveguide 503. m is the diffraction order, m=1, 2, 3, . . . λ1 is the wavelength of the optical signal with wavelength λ1 in the second optical signal. φ (λ1-2) is the phase generated when an optical signal of wavelength λ1 in the second optical signal passes through the central waveguide of the eleven waveguides 503 (the waveguide 503 with i=0 is the central waveguide). ΔL is the difference in length between two adjacent waveguides 503. ΔL is designed based on an integer period (an integer multiple of 2π) of the central wavelength (for example, in this example, the central wavelength is λ2). Therefore, at a non-central wavelength of λ1, an offset Δl1 occurs, and therefore, a phase difference Δφ (λ1-1) is generated. Therefore, the phase difference between the optical signals of wavelength λ1 in the second optical signal output by two adjacent waveguides 503 of the eleven waveguides 503 is fixed, but is not an integer multiple of 2π. The optical signal of wavelength λ2 in the second optical signal is transmitted through multiple different optical paths in the eleven waveguides 503, and the phase of the optical signal of wavelength λ2 in the second optical signal output by any one of the eleven waveguides 503 is also different. Equation n c ΔL=mλ2 and formula Φ i =φ (λ2-1) +φ (λ2-2) See +i2mπ. n cis the refractive index of the material of the waveguide 503. m is the diffraction order, m=1, 2, 3, . . . λ2 is the wavelength of the optical signal with wavelength λ2 in the second optical signal. φ (λ2-2) is the phase generated when an optical signal of wavelength λ2 (center wavelength) in the second optical signal passes through a central waveguide among the multiple waveguides 503. ΔL is the difference in length between two adjacent waveguides 503. ΔL is designed based on an integer period (an integer multiple of 2π) of the center wavelength (λ2). Therefore, the phase difference between the optical signals of wavelength λ2 in the second optical signal output by two adjacent waveguides 503 among the eleven waveguides 503 is fixed, and the phase difference is an integer multiple of 2π. An optical signal of wavelength λ3 in the second optical signal is transmitted through multiple different optical paths among the eleven waveguides 503, and the phase of the optical signal of wavelength λ3 in the second optical signal output by any one of the eleven waveguides 503 is also different. Equation n s ΔL=mλ3-n s Δl1 and formula Φ i =φ (λ3-1) +φ (λ3-2) +i*(2mπ-Δφ (λ3-1) ) See n s is the refractive index of the material of the waveguide 503. m is the diffraction order, m=1, 2, 3, . . . λ3 is the wavelength of the optical signal with wavelength λ3 in the second optical signal. φ (λ3-2) is the phase generated when an optical signal of wavelength λ3 in the second optical signal passes through the central waveguide of the plurality of waveguides 503. ΔL is the difference in length between two adjacent waveguides 503. ΔL is designed based on an integer period (an integer multiple of 2π) of the central wavelength (for example, in this example, the central wavelength is λ2). Therefore, at a non-central wavelength of λ3, an offset Δl1 occurs, and therefore, a phase difference Δφ (λ3-1) Therefore, the phase difference between the optical signals of wavelength λ3 in the second optical signal output by two adjacent waveguides 503 of the eleven waveguides 503 is fixed but is not an integer multiple of 2π.

[0044] The phase shift structure 506 is configured to adjust the amplitude of the optical signal of one or more wavelengths in the second optical signal to generate a third optical signal. For example, the phase shift structure 506 can be disposed in the coupler 504, so that the manufacturing process of the phase shift structure 506 is simple. See FIG. 9. The relationship between the divergence field distribution and the divergence angle of the second optical signal is Gaussian, with the amplitude smoothly decreasing from the center to the outside. The size of the second optical signal on the xy plane is the size of the optical spot of the second optical signal. For example, the amplitudes of the optical signal of wavelength λ1 in the second optical signal and the optical signal of wavelength λ3 in the second optical signal are small, while the amplitude of the optical signal of wavelength λ2 (center wavelength) in the second optical signal is large. The phase shift structure 506 can change the amplitude of the optical signal of wavelength λ1 in the second optical signal and the optical signal of wavelength λ3 in the second optical signal. See FIG. 10, for example. Specifically, the phase shift structure 506 adjusts the phase of the second optical signal to adjust the amplitude of the optical signal with wavelength λ1 in the second optical signal and the amplitude of the optical signal with wavelength λ3 in the second optical signal to generate a third optical signal. The amplitude of the optical signal with wavelength λ1 in the third optical signal is greater than the amplitude of the optical signal with wavelength λ1 in the second optical signal. The amplitude of the optical signal with wavelength λ3 in the third optical signal is greater than the amplitude of the optical signal with wavelength λ3 in the second optical signal. For example, as shown in FIG. 10, the relationship between the divergence field distribution and the divergence angle of the third optical signal is a flat-top distribution. The size of the third optical signal on the xy plane is the size of the optical spot of the third optical signal. For example, within a predetermined radius range centered on the center of the optical spot, the difference between the amplitudes of any two optical signals with wavelengths in the third optical signal is less than a predetermined value. In other words, the amplitudes of the optical signals with different wavelengths in the third optical signal are approximately equal.

[0045] The phase shift structure 506 is configured to change the amplitude of one or more optical signals of different wavelengths in the second optical signal to generate a third optical signal. For example, the relationship between the divergence field distribution and the divergence angle of the third optical signal output by the phase shift structure 506 is a flat-top distribution, but the phase shift structure 506 does not change the phase difference between the optical signals of wavelength λ1 in the second optical signal output by two adjacent waveguides 503 of the eleven waveguides 503, does not change the phase difference between the optical signals of wavelength λ2 in the second optical signal output by two adjacent waveguides 503 of the eleven waveguides 503, and does not change the phase difference between the optical signals of wavelength λ3 in the second optical signal output by two adjacent waveguides 503 of the eleven waveguides 503. Therefore, the phase difference between the optical signals of wavelength λ1 in the third optical signal output by two adjacent phase shift structures 506 of the eleven phase shift structures 506 is fixed and is not an integer multiple of 2π. The phase difference between the optical signals of wavelength λ2 in the third optical signal output by two adjacent phase shift structures 506 of the eleven phase shift structures 506 is fixed and is an integer multiple of 2π. The phase difference between the optical signals of wavelength λ3 in the third optical signal output by two adjacent phase shift structures 506 of the eleven phase shift structures 506 is fixed and is not an integer multiple of 2π.

[0046] The coupler 504 is configured to receive the third optical signal generated by the phase shift structure 506, generate three fourth optical signals based on the third optical signal, and couple one fourth optical signal to one waveguide 505 for transmission. Specifically, see FIG. 11 . One embodiment of this application provides a diagram of the configuration of the coupler 504. The phase shift structure 506 is disposed within the coupler 504, and the couplers 504 and 502 are mirror images of each other. The input ends of the three waveguides 505 are disposed on the circumference of a Rowland circle of the coupler 504. The output ends of the eleven waveguides 503 are disposed on a circumference having a radius twice the radius of the Rowland circle. The amplitude of one or more wavelengths of optical signals in the second optical signal transmitted to the phase shift structure 506 by any one of the waveguides 503 is adjusted using the phase shift structure 506 to generate a third optical signal. The third optical signal is freely transmitted within the coupler 504. The coupler 504 generates three fourth optical signals based on the third optical signal. Any two of the fourth optical signals have different wavelengths. The coupler 504 couples one fourth optical signal to one waveguide 505 for transmission. The waveguide 505 is configured to output the fourth optical signals.

[0047] For example, the fourth optical signal output by the first waveguide 505 of the three waveguides 505 is an optical signal of wavelength λ1, the fourth optical signal output by the second waveguide 505 of the three waveguides 505 is an optical signal of wavelength λ2, and the fourth optical signal output by the third waveguide 505 of the three waveguides 505 is an optical signal of wavelength λ3. The second waveguide 505 of the three waveguides 505 is the central waveguide, and the wavelength of the optical signal of wavelength λ2 is the central wavelength. When the optical signals of wavelength λ1 in the third optical signal generated by each of the eleven phase shift structures 506 are freely transmitted from each phase shift structure 506 through the coupler 504 to the first of the three waveguides 505, the optical paths are different, and as a result, the phases of the optical signals of wavelength λ1 in the third optical signal generated by the different phase shift structures 506 are also different when these optical signals of wavelength λ1 are transmitted to the first of the three waveguides 505. i=l+i*Δl2 and formula Φ i =φ (λ1-1) +φ (λ1-2) +φ (λ1-3) +i*(2mπ-Δφ (λ1-1) +Δφ (λ1-2) ) See L i is the length from the i-th waveguide 503 to one of the eleven waveguides 503. l is the length from the central waveguide to that waveguide 505 among the multiple waveguides 503. φ (λ1-3) is the phase generated when an optical signal of wavelength λ1 in the third optical signal reaches the first of the three waveguides 505. All of the waveguides 505 have the same length from the central waveguide of the plurality of waveguides 503. When a non-central waveguide of the plurality of waveguides 503 reaches a different waveguide 505, an offset Δl2 occurs, and therefore a phase difference Δφ (λ1-2) When the optical signal of wavelength λ1 in the third optical signal reaches the first of the three waveguides 505, a phase difference Δφ is generated. (λ1-2) The value of Δφ (λ1-1)As a result, the phase difference between the optical signals of wavelength λ1 in the third optical signal generated by the different phase-shift structures 506 is exactly an integer multiple of 2π when these optical signals of wavelength λ1 are transmitted to the first of the three waveguides 505. See FIG. 12 . For example, the phase of the optical signal of wavelength λ1 in the third optical signal freely transmitted through the coupler 504 to the first of the three waveguides 505 by the x-th phase-shift structure 506 of the eleven phase-shift structures 506 in the first of the three waveguides 505 is (1+2*x)*π, where x=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]. Therefore, the optical signals of wavelength λ1 in the third optical signal generated by each of the eleven phase-shift structures 506 realize constructive interference in the first of the three waveguides 505. A first fourth optical signal is generated, and the optical intensity of the first fourth optical signal is a first predetermined value. Specifically, the fourth optical signal is an optical signal with wavelength λ1. The first waveguide 505 of the three waveguides 505 outputs the first fourth optical signal. For example, when the optical signal with wavelength λ1 in the third optical signal reaches the second waveguide 505 of the three waveguides 505, a phase difference Δφ (λ1-2) The value of Δφ (λ1-1), and as a result, the phase difference between the optical signals of wavelength λ1 in the third optical signal generated by the different phase-shift structures 506 when these optical signals of wavelength λ1 are transmitted to the first of the three waveguides 505 is not an integer multiple of 2π. See FIG. 13. The phase at the second of the three waveguides 505 of the optical signal of wavelength λ1 in the third optical signal that is freely transmitted through the coupler 504 to the second of the three waveguides 505 by the xth phase-shift structure 506 of the eleven phase-shift structures 506 is ((11*(x-1)) / 5)*π, where x=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]. The phase difference between the optical signals of wavelength λ1 in the third optical signal generated by the different phase-shift structures 506 is not an integer multiple of 2π when these optical signals of wavelength λ1 are transmitted to the second of the three waveguides 505. Thus, the optical signals of wavelength λ1 in the third optical signal generated by each of the eleven phase-shift structures 506 undergo destructive interference in the second of the three waveguides 505. Similarly, the optical signals of wavelength λ1 in the third optical signal generated by each of the eleven phase-shift structures 506 undergo destructive interference in the third of the three waveguides 505.

[0048] When the optical signals of wavelength λ2 in the third optical signal generated by each of the eleven phase-shift structures 506 are freely transmitted from each phase-shift structure 506 through the coupler 504 to the second waveguide 505 of the three waveguides 505, the optical paths are the same, and as a result, the phases of the optical signals of wavelength λ2 in the third optical signal generated by the different phase-shift structures 506 are the same when these optical signals of wavelength λ2 are transmitted to the second waveguide 505 of the three waveguides 505. The formula Φ i =φ (λ2-1) +φ (λ2-2) +φ (λ2-3) See +i2mπ. φ (λ2-3)is the phase generated when the optical signal of wavelength λ2 in the third optical signal reaches the second of the three waveguides 505. It can be seen that the phase difference between the optical signals of wavelength λ2 in the third optical signal generated by the different phase-shift structures 506 is exactly an integer multiple of 2π when these optical signals of wavelength λ2 are transmitted to the second of the three waveguides 505. See FIG. 12 . The phase at the second of the three waveguides 505 of the optical signal of wavelength λ2 in the third optical signal that is freely transmitted through the coupler 504 to the second of the three waveguides 505 by the x-th phase-shift structure 506 of the eleven phase-shift structures 506 is (1+2*x)*π, where x=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]. Therefore, the optical signal of wavelength λ2 in the third optical signal generated by each of the eleven phase-shift structures 506 realizes constructive interference in the second waveguide 505 of the three waveguides 505. A second fourth optical signal is generated, and the optical intensity of the second fourth optical signal is also a first predetermined value. The fourth optical signal is specifically an optical signal of wavelength λ2. The second waveguide 505 of the three waveguides 505 outputs the second fourth optical signal. When the optical signal of wavelength λ2 in the third optical signal generated by each of the eleven phase-shift structures 506 is freely transmitted from each phase-shift structure 506 through the coupler 504 to the first waveguide 505 of the three waveguides 505, the optical paths are different. As a result, the phases of the optical signals of wavelength λ2 in the third optical signals generated by different phase-shift structures 506 are also different when these optical signals of wavelength λ2 are transmitted to the first waveguide 505 of the three waveguides 505. i =l+i*Δl2 and formula Φ i =φ (λ2-1) +φ (λ2-2) +φ (λ2-3) +i*(2mπ+Δφ (λ2) ) When an optical signal of wavelength λ2 in the third optical signal is transmitted to the first of the three waveguides 505, a phase difference Δφ (λ2)As a result, the phase difference between the optical signals of wavelength λ2 in the third optical signal generated by the different phase-shift structures 506 is not an integer multiple of 2π when these optical signals of wavelength λ2 are transmitted to the first of the three waveguides 505. See FIG. 13. For example, the phase at the first of the three waveguides 505 of the optical signal of wavelength λ2 in the third optical signal that is freely transmitted through the coupler 504 to the first of the three waveguides 505 by the xth phase-shift structure 506 of the eleven phase-shift structures 506 is ((11*(x-1)) / 5)*π, where x=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]. Therefore, the optical signal of wavelength λ2 in the third optical signal generated by each of the eleven phase-shift structures 506 undergoes destructive interference in the first waveguide 505 of the three waveguides 505. Similarly, the optical signal of wavelength λ2 in the third optical signal generated by each of the eleven phase-shift structures 506 also undergoes destructive interference in the third waveguide 505 of the three waveguides 505.

[0049] When the optical signal of wavelength λ3 in the third optical signal generated by each of the eleven phase shift structures 506 is freely transmitted from each phase shift structure 506 through the coupler 504 to the third waveguide 505 of the three waveguides 505, the optical paths are different, and as a result, the phases of the optical signals of wavelength λ3 in the third optical signal generated by the different phase shift structures 506 are also different when these optical signals of wavelength λ3 are transmitted to the third waveguide 505 of the three waveguides 505. i =l+i*Δl2 and formula Φ i =φ (λ3-1) +φ (λ3-2) +φ (λ3-3) +i*(2mπ-Δφ (λ3) +Δφ (λ3) ) See L i is the length from the i-th waveguide 503 to one of the eleven waveguides 503. l is the length from the central waveguide to that waveguide 505 among the multiple waveguides 503. φ (λ3-3)is the phase generated when an optical signal of wavelength λ3 in the third optical signal reaches the third of the three waveguides 505. The lengths from the central waveguide of the plurality of waveguides 503 to all of the waveguides 505 are the same. An offset Δl2 occurs when a non-central waveguide of the plurality of waveguides 503 reaches a different waveguide 505, and therefore a phase difference Δφ (λ3-2) When the optical signal of wavelength λ3 in the third optical signal reaches the third of the three waveguides 505, a phase difference Δφ is generated. (λ1-2) The value of Δφ (λ1-1) As a result, the phase difference between the optical signals of wavelength λ3 in the third optical signal generated by different phase-shift structures 506 is exactly an integer multiple of 2π when these optical signals of wavelength λ3 are transmitted to the third waveguide 505 of the three waveguides 505. See FIG. 12 . For example, the phase of the optical signal of wavelength λ3 in the third optical signal freely transmitted through the coupler 504 to the third waveguide 505 of the three waveguides 505 by the x-th phase-shift structure 506 of the eleven phase-shift structures 506 is (1+2*x)π, where x=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]. Therefore, the optical signals of wavelength λ3 in the third optical signal generated by each of the eleven phase-shift structures 506 achieve constructive interference in the third waveguide 505 of the three waveguides 505. A third fourth optical signal is generated. Specifically, the fourth optical signal is an optical signal with wavelength λ3, and the optical intensity of the fourth optical signal is a first predetermined value. The third waveguide 505 of the three waveguides 505 outputs the third fourth optical signal. See FIG. 13 . For example, when the optical signal with wavelength λ3 in the third optical signal reaches the first waveguide 505 of the three waveguides 505, a phase difference Δφ generated is (λ3-2) The value of Δφ (λ3-1), and as a result, the phase difference between the optical signals of wavelength λ3 in the third optical signal generated by the different phase-shift structures 506 when these optical signals of wavelength λ3 are transmitted to the first of the three waveguides 505 is not an integer multiple of 2π. See FIG. 13. The phase at the first of the three waveguides 505 of the optical signal of wavelength λ3 in the third optical signal that is freely transmitted through the coupler 504 to the first of the three waveguides 505 by the x-th phase-shift structure 506 of the eleven phase-shift structures 506 is ((11*(x-1)) / 5)*π, where x=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]. The phase difference between the optical signals of wavelength λ3 in the third optical signal generated by the different phase-shift structures 506 is not an integer multiple of 2π when these optical signals of wavelength λ3 are transmitted to the first of the three waveguides 505. Therefore, the optical signals of wavelength λ3 in the third optical signal output by each of the eleven phase-shift structures 506 undergo destructive interference in the first of the three waveguides 505. Similarly, the optical signals of wavelength λ3 in the third optical signal output by each of the eleven phase-shift structures 506 undergo destructive interference in the second of the three waveguides 505.

[0050] For example, a phase shift structure 506 is disposed between waveguide 503 and coupler 504, or a phase shift structure 506 is disposed within coupler 504. This does not affect the constructive and destructive interference of optical signals of a given wavelength transmitted into waveguide 505.

[0051] For example, in the arrayed waveguide grating 50, the waveguide 501 is configured to transmit a first optical signal to the coupler 502. For example, the first optical signal includes an optical signal with a wavelength λ1, an optical signal with a wavelength λ2, and an optical signal with a wavelength λ3. The coupler 502 generates k second optical signals based on the first optical signal and couples one second optical signal to one waveguide 503 for transmission. The second optical signal also includes an optical signal with a wavelength λ1, an optical signal with a wavelength λ2, and an optical signal with a wavelength λ3. The waveguide 503 is configured to transmit the second optical signal to the phase shift structure 506. The phase shift structure 506 is configured to change the amplitude of one or more optical signals of the second optical signal to generate a third optical signal. For example, the relationship between the divergence field distribution and the divergence angle of the second optical signal is Gaussian, with the amplitude smoothly decreasing from the center to the outside. For example, the amplitude of the optical signal of wavelength λ1 in the second optical signal and the amplitude of the optical signal of wavelength λ3 in the second optical signal are small, and the amplitude of the optical signal of wavelength λ2 (center wavelength) in the second optical signal is large. The phase shift structure 506 can change the amplitude of the optical signal of wavelength λ1 in the second optical signal and the amplitude of the optical signal of wavelength λ3 in the second optical signal. Specifically, the phase shift structure 506 can adjust the phase of the second optical signal to adjust the amplitude of the optical signal of wavelength λ1 in the second optical signal and the amplitude of the optical signal of wavelength λ3 in the second optical signal to generate a third optical signal. The amplitude of the optical signal of wavelength λ1 in the third optical signal is larger than the amplitude of the optical signal of wavelength λ1 in the second optical signal. The amplitude of the optical signal of wavelength λ3 in the third optical signal is larger than the amplitude of the optical signal of wavelength λ3 in the second optical signal. The phase shift structure 506 transmits the third optical signal to the coupler 504. The coupler 504 generates n fourth optical signals based on the third optical signal. For example, the n fourth optical signals include one fourth optical signal with a wavelength λ1, one fourth optical signal with a wavelength λ2, and one fourth optical signal with a wavelength λ3. The coupler 504 couples one fourth optical signal to one waveguide 505 for transmission. The waveguide 505 outputs one fourth optical signal. The optical intensity of the fourth optical signal output by the waveguide 505 is positively correlated with the square of the amplitude of the fourth optical signal output by the waveguide 505.The optical intensity of the fourth optical signal output by the waveguide 505 is negatively correlated with the insertion loss of the waveguide 505. When the amplitude of the optical signal with wavelength λ1 in the third optical signal is greater than the amplitude of the optical signal with wavelength λ1 in the second optical signal, the amplitude of the fourth optical signal with wavelength λ1 generated based on the third optical signal increases. Therefore, the insertion loss of the waveguide 505 outputting the fourth optical signal with wavelength λ1 decreases. When the amplitude of the optical signal with wavelength λ3 in the third optical signal is greater than the amplitude of the optical signal with wavelength λ3 in the second optical signal, the amplitude of the fourth optical signal with wavelength λ3 generated based on the third optical signal increases. Therefore, the insertion loss of the waveguide 505 outputting the fourth optical signal with wavelength λ3 decreases.

[0052] 14. In some embodiments, a phase shift structure 507 is further disposed between the waveguide 501 and the coupler 502. Alternatively, the phase shift structure 507 may be disposed within the coupler 502 so that the manufacturing process of the phase shift structure 507 is simplified. The waveguide 501 is specifically configured to transmit a first optical signal to the phase shift structure 507. For example, the first optical signal includes an optical signal with a wavelength λ1, an optical signal with a wavelength λ2, and an optical signal with a wavelength λ3.

[0053] The phase-shift structure 507 is configured to adjust the amplitude of one or more optical signals of different wavelengths in the first optical signal to generate a fifth optical signal. See, for example, FIG. 9 . The relationship between the divergence field distribution and the divergence angle of the first optical signal is a Gaussian distribution, with the amplitude smoothly decreasing from the center to the outside. The size of the first optical signal on the xy plane is the size of the optical spot of the first optical signal. For example, the amplitudes of the optical signals of wavelengths λ1 and λ3 in the first optical signal are small, while the amplitude of the optical signal of wavelength λ2 (center wavelength) in the first optical signal is large. The phase-shift structure 507 can change the amplitude of the optical signal of wavelength λ1 in the first optical signal and the amplitude of the optical signal of wavelength λ3 in the second optical signal. See, for example, FIG. 10 . Specifically, the phase-shift structure 507 can adjust the amplitude of the optical signal of wavelength λ1 in the first optical signal and the amplitude of the optical signal of wavelength λ3 in the second optical signal by adjusting the phase of the first optical signal to generate a fifth optical signal. The amplitude of the optical signal with wavelength λ1 in the fifth optical signal is greater than the amplitude of the optical signal with wavelength λ1 in the first optical signal. The amplitude of the optical signal with wavelength λ3 in the fifth optical signal is greater than the amplitude of the optical signal with wavelength λ3 in the first optical signal. For example, as shown in FIG. 10, the relationship between the divergence field distribution and the divergence angle of the fifth optical signal is a flat-top distribution. The size of the third optical signal on the plane formed by x and y is the size of the optical spot of the third optical signal. For example, within a predetermined radius range centered on the center of the optical spot, the difference between the amplitudes of any two optical signals with wavelengths in the fifth optical signal is less than a predetermined value. In other words, the amplitudes of multiple optical signals with different wavelengths in the fifth optical signal are approximately equal.

[0054] The coupler 502 is specifically configured to receive a fifth optical signal generated by the phase-shift structure 507, generate k second optical signals based on the fifth optical signal, and couple one second optical signal to one waveguide 503 for transmission. Specifically, see FIG. 15 . One embodiment of this application provides a diagram of the configuration of the coupler 502. The phase-shift structure 507 is specifically disposed within the coupler 502. The output end of the waveguide 501 is disposed on the circumference of a Rowland circle of the coupler 502, and the input ends of the eleven waveguides 503 are disposed on the circumference of a diffraction grating circle having a radius twice the radius of the Rowland circle. The phase-shift structure 507 changes the amplitude of the optical signal of one or more wavelengths in the first optical signal transmitted by the waveguide 501 from the output end of the waveguide 501 to the coupler 502 to generate the fifth optical signal. The fifth optical signal is freely transmitted within the coupler 502. The coupler 502 generates eleven second optical signals based on the fifth optical signal. Specifically, the eleven second optical signals have equal power, and each second optical signal includes an optical signal of wavelength λ1, an optical signal of wavelength λ2, and an optical signal of wavelength λ3. One second optical signal is coupled to one waveguide 503 for transmission. Specifically, when the optical signal of wavelength λ1 in the fifth optical signal is freely transmitted within the coupler 502 to any one of the eleven waveguides 503, the optical signal of wavelength λ1 in the fifth optical signal has a consistent optical path and a consistent phase. The phase is expressed as Φ i =φ (λ1-1) When the optical signal of wavelength λ2 in the fifth optical signal is freely transmitted in the coupler 502 to any one of the eleven waveguides 503, the optical signal of wavelength λ2 in the fifth optical signal has a consistent optical path and a consistent phase. The phase is expressed as Φ i =φ (λ2-1) When the optical signal of wavelength λ3 in the fifth optical signal is freely transmitted in the coupler 502 to any one of the eleven waveguides 503, the optical signal of wavelength λ3 in the fifth optical signal has a consistent optical path and a consistent phase. The phase is expressed as Φ i =φ (λ3-1) It is written as follows.

[0055] If a phase-shift structure 507 is further disposed between the waveguide 501 and the coupler 502, the phase-shift structure 507 can change the amplitude of the optical signal of one or more wavelengths in the first optical signal to generate a fifth optical signal. For example, if the relationship between the divergence field distribution and the divergence angle of the fifth optical signal is a flat-top distribution, the relationship between the divergence field distribution and the divergence angle of the second optical signal generated by the coupler 502 based on the fifth optical signal also is a flat-top distribution, so that the insertion loss of some waveguides 505 in the arrayed-waveguide grating 50 is further reduced.

[0056] For example, the phase-shift structure 506 adjusts the amplitude of the optical signal of one or more wavelengths in the second optical signal to generate a third optical signal. The divergence angle of the third optical signal is equal to the corresponding central angle on the Rowland circle of the arc between the first waveguide 505 and the nth waveguide 505. Specifically, see FIG. 10 . When the optical signal shown in FIG. 10 is specifically any third optical signal, the phase-shift structure 506 can further adjust the divergence angle of the third optical signal. See FIG. 10 . The divergence angle is α. See FIG. 11 . When three waveguides 505 are present, the corresponding central angle on the Rowland circle of the arc between the first waveguide 505 and the third waveguide 505 is β. If the divergence angle α is equal to the central angle β, it indicates that when the third optical signal is freely transmitted from the coupler 504 to the three waveguides 505, the third optical signal does not have energy distributed in areas other than the three waveguides 505, which can result in an increase in the device insertion loss of the arrayed waveguide grating 50.

[0057] For example, there is a prior art solution to the problem of high insertion loss of one or more waveguides configured to output an optical signal in an arrayed waveguide grating. See FIG. 16. The arrayed waveguide grating 50 shown in FIG. 16 is based on the arrayed waveguide grating 50 shown in FIG. 5. An auxiliary waveguide 508 is further disposed at the input end of a waveguide 503. When the number of waveguides 503 is k, the number of auxiliary waveguides 508 is k+1. Each of the k-1 auxiliary waveguides 508 out of the k+1 auxiliary waveguides 508 is disposed between two adjacent waveguides 503, forming a configuration in which the auxiliary waveguides 508 are disposed on both sides of the waveguides 503, one of the k+1 auxiliary waveguides is disposed outside the first waveguide 503, and another of the k+1 auxiliary waveguides is disposed outside the kth waveguide 503. In addition, the k+1 auxiliary waveguides 508 and the input ends of the k waveguides 503 are arranged on the circumference of a diffraction grating circle having a radius twice the radius of the Rowland circle. When the coupler 502 is configured to equally couple optical signals to the 11 waveguides 503, the auxiliary waveguides arranged on both sides of the waveguides 503 also have optical signals coupled to them, so that the optical signal coupled to any of the waveguides 503 has more energy.

[0058] For example, an auxiliary waveguide 509 is further disposed at the optical signal output end of the waveguide 503. When the number of waveguides 503 is k, the number of auxiliary waveguides 509 is k+1. To form a configuration in which the auxiliary waveguides 509 are disposed on both sides of the waveguides 503, each of the k-1 auxiliary waveguides 509 is disposed between two adjacent waveguides 503, one of the k+1 auxiliary waveguides 509 is disposed outside the first waveguide 503, and the other of the k+1 auxiliary waveguides 509 is disposed outside the kth waveguide 503. Furthermore, the k+1 auxiliary waveguides 508 and the input ends of the k waveguides 503 are disposed on the circumference of a diffraction grating circle having a radius twice the radius of the Rowland circle. When a waveguide 503 transmits an optical signal to coupler 504, the optical signal transmitted by any one of the waveguides 503 is coupled to auxiliary waveguides 509 located on both sides of that waveguide 503. Thus, the optical signal transmitted by any one of the waveguides 503 to coupler 504 becomes a three-point source (the waveguide and the auxiliary waveguides located on both sides of the waveguide transmit the optical signal to coupler 504) or a multi-point source. Thus, the amplitude distribution of the optical signal transmitted by each waveguide 503 to coupler 504 becomes more uniform as the optical signal diverges within coupler 504.

[0059] However, the divergence angle of the optical signal cannot be changed by placing an auxiliary waveguide. Therefore, in the waveguide 505 shown in Fig. 16, energy is distributed in areas other than the n waveguides 505. As a result, the insertion loss of the arrayed waveguide grating 50 shown in Fig. 16 is high.

[0060] Please refer to Fig. 17. When the four waveguides 505 output an optical signal with wavelength λ1, an optical signal with wavelength λ2, an optical signal with wavelength λ3, and an optical signal with wavelength λ4, respectively, there is energy distributed in regions other than the four waveguides 505, as shown by the dashed lines in Fig. 17.

[0061] For example, in some other embodiments, see FIG. 18 . The arrayed waveguide grating 50 may include three waveguides 501, eleven waveguides 503, and one waveguide 505. Such an arrayed waveguide grating 50 is configured to implement the function of multiplexing optical signals of different wavelengths. Such an arrayed waveguide grating may be disposed in the optical transmission device 20 shown in FIG. 2 or 3. One of the three waveguides 501 is connected to one optical modulator 202, and the waveguide 505 is connected to the optical fiber 30 shown in FIG. 1. When the arrayed waveguide grating 50 is disposed in an optical transmission device, the arrayed waveguide grating 50 may include m waveguides 501, k waveguides 503, and n waveguides 505. The optical transmission device includes s optical modulators, where m is greater than n and s is equal to or less than m. Each of the three waveguides 501 is configured to receive a first optical signal of one wavelength, and the wavelength of the first optical signal received by any two of the three waveguides 501 is different. The waveguides 501 are configured to transmit the first optical signal to the coupler 502. For example, a first waveguide 501 of the three waveguides 501 transmits the first optical signal to the coupler 502, where the first optical signal has a wavelength of λ1; a second waveguide 501 of the three waveguides 501 transmits the first optical signal to the coupler 502, where the first optical signal has a wavelength of λ2; and a third waveguide 501 of the three waveguides 501 transmits the first optical signal to the coupler 502, where the first optical signal has a wavelength of λ3. Coupler 502 is configured to receive a first optical signal transmitted by waveguide 501, generate eleven second optical signals based on the first optical signal, and couple one second optical signal to one waveguide 503 for transmission. For example, a first optical signal of wavelength λ1 is freely transmitted within coupler 502 to generate eleven second optical signals of wavelength λ1, and one second optical signal of wavelength λ1 is coupled to one of the eleven waveguides 503 for transmission. A first optical signal of wavelength λ2 is freely transmitted within coupler 502 to generate eleven second optical signals of wavelength λ2, and one second optical signal of wavelength λ2 is coupled to one of the eleven waveguides 503 for transmission.A first optical signal of wavelength λ3 is freely transmitted within coupler 502 to generate eleven second optical signals of wavelength λ3, and one second optical signal of wavelength λ3 is coupled to one of eleven waveguides 503 for transmission. Waveguides 503 are configured to transmit the second optical signal to phase-shift structures 506. Because the differences in the lengths of the eleven waveguides form an arithmetic progression, the second optical signals of different wavelengths have a predetermined phase difference after being output by the eleven waveguides 503. Phase-shift structures 506 are configured to adjust the amplitude of one or more optical signals of the second optical signal to generate a third optical signal. Phase-shift structures 506 do not change the phase difference between the second optical signals output by different waveguides 503, but only convert the second optical signal into a third optical signal with a flat-top distribution. Therefore, the phase difference between the third optical signals output by different phase-shift structures 506 is the same as the phase difference between the second optical signals output by different waveguides 503. The coupler 504 is configured to receive the third optical signal transmitted by the phase-shift structure 506, generate a fourth optical signal based on the third optical signal, and couple the fourth optical signal to the waveguide 505 for transmission. The waveguide 505 is configured to output the fourth optical signal. If only one waveguide 505 is included, all third optical signals of different wavelengths are focused into the waveguide 505, which is the central waveguide of the coupler 504. In this way, the arrayed-waveguide grating 50 realizes the function of multiplexing optical signals of different wavelengths.

[0062] 18 may also be disposed within coupler 504. For example, phase shift structure 506 may be disposed between waveguide 503 and coupler 504, or phase shift structure 506 may be disposed within coupler 504. This does not affect the fourth optical signal output by waveguide 505.

[0063] 18 , a phase-shift structure 507 is further disposed between the waveguide 501 and the coupler 502. The waveguide 501 is specifically configured to transmit a first optical signal to the phase-shift structure 507. The phase-shift structure 507 is configured to adjust the amplitude of an optical signal of one or more wavelengths in the first optical signal to generate a fifth optical signal. The coupler 502 is specifically configured to receive the fifth optical signal generated by the phase-shift structure 507, generate k second optical signals based on the fifth optical signal, and couple one second optical signal to one second waveguide for transmission.

[0064] 18 may instead be located within coupler 502. For example, the phase shift structure may be located between waveguide 501 and coupler 502, or alternatively, phase shift structure 507 may be located within coupler 502. This does not affect the second optical signal transmitted to waveguide 503.

[0065] 19. The arrayed waveguide grating 50 provided in this embodiment of the present application may further include a substrate 100 (also referred to as a substrate base) and a material layer 200 disposed on the substrate. The waveguides 501, couplers 502, waveguides 503, phase-shift structures 506, couplers 504, and waveguides 505 are fabricated on the material layer 200, and the waveguides 501, couplers 502, waveguides 503, phase-shift structures 506, couplers 504, and waveguides 505 are collectively referred to as an arrayed waveguide grating pattern M. For example, the material of the substrate 100 may be lithium niobate (LiNbO), a III-V semiconductor compound, silicon dioxide (SiO), silicon (Si), a polymer, or glass. The material of the material layer 200 may be silicon (Si), silicon nitride (SiN), silicon oxynitride (SiON), or silicon dioxide. For example, the arrayed waveguide grating 50 may further include another material layer. For example, the arrayed waveguide grating may further include a protection layer 300 disposed on the material layer 200 and close to the substrate, and a protection layer 400 disposed on the material layer 200 and close to the substrate. The protection layer 300 and the protection layer 400 are configured to protect the arrayed waveguide grating pattern fabricated in the material layer 200 and extend the service life of the arrayed waveguide grating. For example, the material of the protection layer 400 and the protection layer 300 is both silicon dioxide.

[0066] For example, the phase-shifting structure 506 in the arrayed waveguide grating 50 includes any one of the Powell prism 61 shown in FIG. 21 , the metalens shown in FIG. 25 , and the liquid crystal lens 63 shown in FIG. 26 . The phase-shifting structure 507 includes any one of the Powell prism 61 shown in FIG. 21 , the metalens shown in FIG. 25 , and the liquid crystal lens 63 shown in FIG. 26 .

[0067] For example, if the phase-shifting structure 506 or the phase-shifting structure 507 includes a Powell prism, see FIG. 20 . An embodiment of this application provides diagrams of the phase-shifting structure 506 or the phase-shifting structure 507 in the material layer 200. See, for example, FIGS. 21 , 22 , and 23 . An embodiment of this application provides diagrams of the configuration of a Powell prism. FIG. 22 is a cross-sectional view taken along line AA′ in FIG. 21 . FIG. 23 is a cross-sectional view taken along line BB′ in FIG. 21 . Along the light transmission direction, the Powell prism 61 includes a first portion 610 and a second portion 611 disposed on the substrate 100. Specifically, the first portion 610 and the second portion 611 are disposed on the protective layer 300. Along the light transmission direction, the first portion 610 includes an end a and an end b. The end a is convex, and the size of the end a along the first direction is smaller than the size of the end b along the first direction, which is perpendicular to the light transmission direction. Along the light transmission direction, the size of the first portion 610 increases continuously along the first direction, and the included angle between the extension lines of the first portion 610 on two sides in the first direction is γ. End a is convex, and the chord length of the convex surface is 2*W1. The radius of curvature R of the convex surface can be obtained according to the formula R=W1*(cos(γ / 2)). Along the light transmission direction, the second portion 611 includes end c and end d. The size of end c along the first direction is equal to the size of end d along the first direction. The size of the second portion 611 along the first direction remains unchanged. Specifically, the size of end c or the size of end d along the first direction is 2*W2, and the size of the second portion 611 along the light transmission direction is L.

[0068] For example, if the difference between the size of end c along the first direction and the size of end d along the first direction is less than or equal to a predetermined value, the size of end c along the first direction can be considered equal to the size of end d along the first direction.

[0069] 22 is a cross-sectional view taken along line AA' in FIG. 21. Along the first direction, the first portion 610 includes subportions 6101, 6102, and 6103. The size of the subportion 6101 along the second direction is smaller than the size of the subportion 6102 along the second direction, and the size of the subportion 6103 along the second direction is smaller than the size of the subportion 6102 along the second direction. The equivalent refractive index of the first portion 610 can be adjusted by adjusting the size of the subportion 6101 along the second direction, the size of the subportion 6102 along the second direction, and the size of the subportion 6103 along the second direction.

[0070] 23 is a cross-sectional view taken along line BB' in FIG. 21. Along the first direction, the second portion 611 includes subportions 6111, 6112, and 6113. The size of the subportion 6111 along the second direction is smaller than the size of the subportion 6112 along the second direction, and the size of the subportion 6113 along the second direction is smaller than the size of the subportion 6112 along the second direction. The equivalent refractive index of the second portion 611 can be adjusted by adjusting the size of the subportion 6111 along the second direction, the size of the subportion 6112 along the second direction, and the size of the subportion 6113 along the second direction.

[0071] See FIG. 24. The Powell prism 61 can change the divergence angle of the optical signal passing through the Powell prism 61. Specifically, when an optical signal with an optical beam width W passes through the Powell prism 61, optical signals of one or more wavelengths in the optical signal output by the Powell prism 61 have the same amplitude. For example, the relationship between the divergence field distribution and the divergence angle of the optical signal output by the Powell prism 61 is a flat-top distribution, and the divergence angle of the optical signal output by the Powell prism 61 is α. The divergence angle α is negatively correlated with the radius of curvature R of the convex surface of the end a of the first portion 610.

[0072] If the divergence angle of the third optical signal generated by the phase-shifting structure 506 is required to be equal to the corresponding central angle on the Rowland circle of the arc between the first waveguide 505 and the nth waveguide 505, and the phase-shifting structure 506 is specifically a Powell prism 61, the radius of curvature R of the convex surface of the end a of the first portion 610 of the Powell prism 61 can be adjusted so that the divergence angle of the third optical signal passing through the Powell prism 61 is equal to the corresponding central angle on the Rowland circle of the arc between the first waveguide 505 and the nth waveguide 505.

[0073] For example, instead, the end c of the second portion of the Powell prism 61 may not be flat, which is not a limitation in this embodiment of the application.

[0074] For example, see FIG. 25 when phase-shifting structure 506 or phase-shifting structure 507 is a metalens. The metalens includes multiple subwavelength gaps 62 arranged along a first direction, and two adjacent subwavelength gaps 62 do not contact each other. The size of one subwavelength gap 62 along the first direction is W. The size of the subwavelength gap 62 along the light transmission direction is L. The distance between the first end of the first subwavelength gap 62 and the first end of the second subwavelength gap 62 of two adjacent subwavelength gaps 62 is D. When an optical signal is transmitted through one subwavelength gap 62, a predetermined phase φ is generated, specifically according to the equation φ=nk0L, where n is the effective refractive index of the subwavelength gap 62. k0=2π / λ is the free-space wave vector. λ is the wavelength of the optical signal transmitted through the subwavelength gap 62. L is the size L of the subwavelength gap 62 along the light transmission direction. The effective refractive index n of the subwavelength gaps 62 can be adjusted by adjusting the size W of the subwavelength gaps 62 along the first direction and the distance D between the first end of a first subwavelength gap and the first end of a second subwavelength gap in two adjacent subwavelength gaps. Accordingly, the value of the size W along the first direction of each of the plurality of subwavelength gaps 62 shown in FIG. 25 , the value of the size L along the light transmission direction of each of the plurality of subwavelength gaps 62, and the value of the distance D between the first end of a first subwavelength gap and the first end of a second subwavelength gap in two adjacent subwavelength gaps are set so that optical signals of one or more wavelengths in the optical signal output by the metalens have the same amplitude. For example, the relationship between the divergence field distribution and the divergence angle of the optical signal output by the metalens is a flat-top distribution.

[0075] If the divergence angle of the third optical signal generated by the phase-shifting structure 506 is required to be equal to the corresponding central angle on the Rowland circle of the arc between the first waveguide 505 and the nth waveguide 505, and if the phase-shifting structure 506 is specifically a metalens, then the value of the size W of each sub-wavelength gap 62 in the metalens along the first direction, the value of the size L along the light transmission direction, and the value of the distance D between a first end of the first sub-wavelength gap and a first end of the second sub-wavelength gap in two adjacent sub-wavelength gaps may be adjusted so that the divergence angle of the third optical signal passing through the metalens is equal to the corresponding central angle on the Rowland circle of the arc between the first waveguide 505 and the nth waveguide 505.

[0076] For example, if the phase-shifting structure 506 or the phase-shifting structure 507 is a liquid crystal lens, see FIG. 26 . The liquid crystal lens 63 includes a liquid crystal layer 631 and electrodes 632 and 633 disposed on both sides of the liquid crystal layer 631 along the second direction. The liquid crystal layer 631 is disposed on the substrate 100. More specifically, the liquid crystal layer 631 is disposed on the protective layer 300, with the electrode 632 disposed on the side of the liquid crystal layer 631 farther from the substrate 100 and the electrode 633 disposed on the side of the liquid crystal layer 631 closer to the substrate 100. The electrode 632 includes a plurality of sub-electrodes 6320. A predetermined voltage is applied to the sub-electrodes 6320 and the electrode layer 633. Under the action of the predetermined voltage, the liquid crystal in the portion of the liquid crystal layer 631 covered by the sub-electrodes 6320 is deflected, and the deflection of the liquid crystal changes the refractive index of the portion of the liquid crystal layer 631 covered by the sub-electrodes 6320. In this case, by applying different voltages to different sub-electrodes 6320 and applying a predetermined voltage to electrode 633, the refractive index of the liquid crystal layer 631 covered by the different sub-electrodes 6320 can be changed. Therefore, by adjusting the voltage values ​​applied to the different sub-electrodes 6320 shown in Figure 26 and the voltage value applied to electrode 633 shown in Figure 26, optical signals of one or more wavelengths in the optical signal output by liquid crystal lens 63 can be adjusted to have the same amplitude. For example, the relationship between the divergence field distribution and the divergence angle of the optical signal output by liquid crystal lens 63 is a flat-top distribution.

[0077] If the divergence angle of the third optical signal generated by the phase-shifting structure 506 is required to be equal to the corresponding central angle on the Rowland circle of the arc between the first waveguide 505 and the nth waveguide 505, and the phase-shifting structure 506 is specifically a liquid crystal lens 63, the voltage values ​​applied to the different sub-electrodes 6320 shown in FIG. 25 and the voltage value applied to the electrode 633 shown in FIG. 25 can be adjusted so that the divergence angle of the third optical signal passing through the liquid crystal lens 63 is equal to the corresponding central angle on the Rowland circle of the arc between the first waveguide 505 and the nth waveguide 505.

[0078] 25 may include a plurality of first sub-electrodes. A predetermined voltage is applied to the first sub-electrode corresponding to the sub-electrode 6320 and the sub-electrode 6320. Under the action of the predetermined voltage, the liquid crystal in the portion of the liquid crystal layer 631 covered by the sub-electrode 6320 is deflected, and the deflection of the liquid crystal changes the refractive index of the portion of the liquid crystal layer 631 covered by the sub-electrode 6320.

[0079] In some other embodiments, to enable arrayed waveguide grating 50 to implement both the function of multiplexing multiple optical signals of different wavelengths and the function of separating multiple optical signals of different wavelengths within one optical signal beam, a phase shift structure may be further disposed between waveguide 503 and coupler 502 in the arrayed waveguide grating shown in FIG. 7. Phase shift structure 506 adjusts the optical intensity of the optical signal output by waveguide 505 so that the insertion loss of each waveguide 505 is low when waveguide 505 outputs an optical signal. A phase shift structure is disposed between waveguide 501 and coupler 502 to adjust the optical intensity of the optical signal output by waveguide 503 so that the insertion loss of each waveguide 501 is low when waveguide 501 outputs an optical signal.

[0080] Although this application has been described with reference to specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of this application. Correspondingly, the specification and accompanying drawings are merely illustrative examples of this application, as defined by the appended claims, and any modifications, variations, combinations, or equivalents covering the scope of this application are contemplated. It is apparent that those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Thus, it is intended that this application also cover such modifications and variations as long as they fall within the scope of the claims of this application and equivalent technologies.

Claims

1. An arrayed waveguide grating having m first waveguides, a first coupler, k second waveguides, a second coupler, and n third waveguides, wherein the first coupler is connected between the first waveguide and the second waveguide, and the second coupler is connected between the second waveguide and the third waveguide, m, n, and k are all positive integers, the lengths of the k second waveguides increase in order, and the difference between the lengths of two adjacent second waveguides is a fixed value; a first phase shift structure is further disposed between the second waveguide and the second coupler; the first waveguide is configured to transmit a first optical signal to the first coupler; the first coupler is configured to receive the first optical signal transmitted by the first waveguide, generate k second optical signals based on the first optical signal, and couple one second optical signal to one second waveguide for transmission; the second waveguide is configured to transmit the second optical signal to the first phase shift structure; the first phase-shift structure is configured to adjust the amplitude of one or more optical signals of different wavelengths in the second optical signal to generate a third optical signal; the second coupler is configured to receive the third optical signal generated by the first phase-shift structure, generate n fourth optical signals based on the third optical signal, and couple one fourth optical signal to one third waveguide for transmission; and the third waveguide is configured to output the fourth optical signal; Arrayed waveguide grating.

2. a second phase shift structure is further disposed between the first waveguide and the first coupler; the first waveguide is specifically configured to transmit the first optical signal to the second phase shift structure; the second phase-shift structure is configured to adjust amplitudes of a plurality of optical signals of different wavelengths in phase with the first optical signal to generate a fifth optical signal; the first coupler is specifically configured to receive the fifth optical signal generated by the second phase-shift structure, generate k second optical signals based on the fifth optical signal, and couple one second optical signal to one second waveguide for transmission; 2. The arrayed waveguide grating of claim 1.

3. a divergence angle of the third optical signal is equal to a corresponding central angle on a Rowland circle of an arc between the first third waveguide and the nth third waveguide; 3. The arrayed waveguide grating according to claim 1 or 2.

4. the first phase shift structure is disposed within the second coupler; 2. The arrayed waveguide grating of claim 1.

5. the second phase shift structure is disposed within the first coupler; 3. The arrayed waveguide grating according to claim 2.

6. the first phase shift structure comprises one of a Powell prism, a metalens, and a liquid crystal lens; 2. The arrayed waveguide grating of claim 1.

7. the second phase shift structure comprises one of a Powell prism, a metalens, and a liquid crystal lens; 3. The arrayed waveguide grating according to claim 2.

8. a difference between the amplitudes of any two optical signals of different wavelengths among the plurality of optical signals of different wavelengths in the third optical signal is smaller than a predetermined value; 2. The arrayed waveguide grating of claim 1.

9. the arrayed waveguide grating further comprises a substrate, and the m first waveguides, the first coupler, the k second waveguides, the first phase-shift structure, the second coupler, and the n third waveguides are fabricated on the substrate.

9. The arrayed waveguide grating according to claim 1.

10. 10. An optical transmitter comprising a light source, s optical modulators, and the arrayed waveguide grating according to claim 1, one of the s optical modulators connects the light source to one first waveguide of the arrayed waveguide grating, s is equal to or less than m, and m is greater than n; Optical transmitter.

11. 10. An optical transmitter comprising: s light sources; s optical modulators; and the arrayed waveguide grating according to claim 1, one of the s optical modulators connects one of the s light sources to one first waveguide of the arrayed waveguide grating, s is equal to or less than m and m is greater than n; Optical transmitter.

12. 10. An optical receiving device comprising the arrayed waveguide grating according to claim 1 and s optical receivers, one third waveguide of the arrayed waveguide grating is connected to one optical receiver, s is equal to or less than n, and m is smaller than n; Optical receiving device.

13. 13. An optical communication system comprising: an optical transmitter according to claim 10 or 11; an optical receiver according to claim 12; and an optical fiber connecting said optical transmitter and said optical receiver.

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