Optical signal receiving unit, transmitting unit, chip and processing method

Abstract

This invention provides an optical signal receiving unit, a transmitting unit, a chip, and a processing method. The optical signal receiving unit includes: a first edge coupler, a pair of demultiplexers, and a polarization processor. The polarization processor receives the optical signal emitted by the first edge coupler and converts it into two transmitted optical signals, wherein at least one of the transmitted optical signals uses a waveguide with a fundamental transverse magnetic mode for polarization orthogonal transmission. The demultiplexer includes at least two transmission channels and is used to decompose one of the transmitted optical signals into optical signals of different wavelengths. This invention reduces process sensitivity by ensuring that at least one of the optical signals arriving at the demultiplexer is transmitted by a waveguide with a fundamental transverse magnetic mode.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, and in particular to an optical signal receiving unit, a transmitting unit, a chip, and a processing method. Background Technology

[0002] To meet the demands and development trends for larger information capacity and faster transmission rates, wavelength division multiplexing (WDM) technology has been proposed. Its key components are the wavelength division multiplexer (Mux) and demultiplexer (Demux). Meanwhile, silicon-based optoelectronic chips, leveraging mature CMOS technology, can realize the development and integration of various optical devices, effectively reducing the cost of modules in optical communication and achieving module miniaturization. Silicon-based WDM (demultiplexer) devices based on the cascaded Mach-Zehnder interferometer (MZI) structure have been widely studied due to their excellent performance. Taking a four-channel demultiplexer (Demux) as an example, the conventional technique used by researchers in this field is to design the receiver of the silicon-based optoelectronic chip as follows... Figure 1 The block diagram shown illustrates that the receiver includes an edge coupler (EC) 101, a polarization splitter and rotator (PSR) 102, a TE mode waveguide 103, demultiplexers A104 and A105, and a PD array 106. Both demultiplexers A and B are four-channel, enabling them to split a beam of light into four different wavelengths. The TE mode is the Basic Horizontal Electric Mode (TE). Figure 1 The working principle of the receiver of the silicon-based optoelectronic chip shown is as follows: The PSR converts the optical signal transmitted through a waveguide with two orthogonal polarization modes into an optical signal transmitted through two waveguides with two orthogonal polarization modes, both in TE mode. Therefore, both demultiplexer A and demultiplexer B need to be designed based on the TE mode. However, this structure is very sensitive to changes in the manufacturing process. For example, when the waveguide size changes, the overall performance of the demux will deteriorate, such as reducing the channel bandwidth, increasing channel crosstalk, affecting optical insertion loss, and shifting the channel center wavelength. This will greatly reduce the yield of the device. Furthermore, commonly used PSR devices are generally large in size, about several hundred micrometers long, which makes the design difficult and is not conducive to the miniaturization of silicon photonic chips. Moreover, the overall performance of the receiver is limited by the performance parameters of the PSR, such as loss and polarization extinction ratio.

[0003] Therefore, this invention proposes an optical signal receiving unit, a transmitting unit, a chip, and a processing method to reduce the process sensitivity of Mux and Demux. Summary of the Invention

[0004] This invention provides an optical signal receiving unit, a transmitting unit, a chip, and a processing method to solve the technical problem of high process sensitivity of Mux and Demux based on the cascaded Mach-Zehnder interferometer (MZI) structure in the prior art.

[0005] In a first aspect, the present invention provides an optical signal receiving unit, comprising: a first edge coupler, a pair of demultiplexers, and a polarization processor; the polarization processor is used to receive an optical signal emitted by the first edge coupler and convert the optical signal emitted by the first edge coupler into two transmitted optical signals, wherein the polarization orthogonal mode of the waveguide used for transmitting the optical signal in at least one of the two transmitted optical signals is a basic transverse magnetic mode; the demultiplexer includes at least two transmission channels and is used to decompose the optical signal transmitted in one of the two channels into optical signals of different wavelengths.

[0006] Its beneficial effect is that, compared with the existing technology where the optical signals arriving at the demultiplexer are all transmitted through waveguides in the basic horizontal electric mode (TE), the present invention ensures that at least one of the optical signals arriving at the demultiplexer is transmitted through a waveguide in the basic horizontal electric mode, which can reduce process sensitivity.

[0007] Optionally, the polarization processor includes a polarization beamsplitter; the polarization beamsplitter receives the optical signal emitted by the first edge coupler and converts the optical signal emitted by the first edge coupler into two transmitted optical signals, wherein the polarization orthogonal mode of the waveguide used for transmitting the optical signal in one of the two paths is a basic transverse magnetic mode, and the polarization orthogonal mode of the waveguide used for transmitting the optical signal in the other of the two paths is a basic transverse electric mode. Its advantages are that by eliminating the PSR in the prior art through the polarization processor, the overall area can be reduced, which is beneficial to the miniaturization of silicon chips.

[0008] Optionally, the polarization processor includes a polarization beamsplitter and a polarization rotator. The polarization beamsplitter receives the optical signal emitted by the first edge coupler and converts it into two transmitted optical signals. One of the transmitted optical signals uses a waveguide with a fundamental transverse magnetic polarization mode, and the other uses a waveguide with a fundamental transverse electric polarization mode. The polarization rotator changes the transverse electric polarization mode of the waveguide in the other transmitted optical signal path from the fundamental transverse magnetic polarization mode to the fundamental transverse magnetic polarization mode. The advantage is that by ensuring all optical signals arriving at the demultiplexer are transmitted through waveguides in the fundamental transverse magnetic mode, the process sensitivity is significantly reduced.

[0009] Optionally, the optical signal receiving unit further includes a photodetector array, which is used to receive the optical signal emitted by the demultiplexer and convert it into photocurrent to complete the conversion from optical signal to electrical signal.

[0010] Optionally, the demultiplexer includes: at least one process-sensitive suppression unit, the process-sensitive suppression unit including a first directional coupler, a second directional coupler, a first optical waveguide delay line, and a second optical waveguide delay line; one end of the first optical waveguide delay line is connected to a first end of the first directional coupler, and the other end of the first optical waveguide delay line is connected to a second end of the second directional coupler; one end of the second optical waveguide delay line is connected to a third end of the first directional coupler, and the other end of the second optical waveguide delay line is connected to a fourth end of the second directional coupler.

[0011] Optionally, the width of the waveguide in the first and second directional couplers ranges from 1.3 to 2.5 micrometers. The advantage is that the commonly used width of the waveguide in the first and second directional couplers is 0.7-0.8 micrometers, which has high process sensitivity. This invention reduces process sensitivity by limiting the width of the waveguide in the first and second directional couplers to 1.3-2.5 micrometers.

[0012] Optionally, the width of the waveguide in the first optical waveguide delay line and the second optical waveguide delay line is in the range of 1.3-2.5 micrometers.

[0013] Secondly, the present invention provides a silicon-based optoelectronic chip, comprising: at least one optical signal receiving unit. Its beneficial effects are the same as those in the first aspect.

[0014] Thirdly, the present invention provides an optical signal transmission unit, comprising: at least one mode conversion unit and a wavelength division multiplexer; the mode conversion unit is used to change the polarization orthogonal mode of the waveguide transmitting the optical signal from a basic transverse electric mode to a basic transverse magnetic mode; the wavelength division multiplexer is used to receive the optical signal emitted by at least one mode conversion unit and combine the received optical signal into a beam of optical signal.

[0015] Its beneficial effect is to reduce process sensitivity.

[0016] Optionally, the mode conversion unit includes: a light source, a second edge coupler, an electro-optic modulator, and a polarization rotator; the light source is used to emit an optical signal; the second edge coupler is used to receive the optical signal emitted by the light source and transmitted through a waveguide with a polarization orthogonal mode of basic transverse electric mode; the electro-optic modulator is used to electro-optically modulate the optical signal emitted by the second edge coupler; the polarization rotator is used to receive the optical signal emitted by the second edge coupler after modulation by the electro-optic modulator, and is used to change the polarization orthogonal mode of the waveguide transmitting the optical signal from a basic transverse electric mode to a basic transverse magnetic mode. Its beneficial effect is that it effectively reduces process sensitivity.

[0017] Fourthly, the present invention provides a method for processing optical signals, applied to an optical signal receiving unit as described in any one of the first aspects, comprising: providing the optical signal receiving unit, the optical signal receiving unit including a first edge coupler, a pair of demultiplexers, and a polarization processor; the first edge coupler receiving an optical signal transmitted through a waveguide having two polarization orthogonal modes; the polarization processor receiving an optical signal emitted by the first edge coupler and converting the optical signal emitted by the first edge coupler into two transmitted optical signals, wherein at least one of the two transmitted optical signals has a waveguide with a fundamental transverse magnetic mode for transmitting the optical signal; the demultiplexer including at least two transmission channels and decomposing the optical signal transmitted in one of the two channels into optical signals of different wavelengths.

[0018] Fifthly, the present invention provides a method for processing optical signals, applied to an optical signal transmitting unit as described in any one of the third aspects, comprising: providing the optical signal transmitting unit, the optical signal transmitting unit including at least one mode conversion unit and a wavelength division multiplexer; the mode conversion unit converting the polarization orthogonal mode of the waveguide transmitting the optical signal from a basic transverse electric mode to a basic transverse magnetic mode; the wavelength division multiplexer receiving the optical signal emitted by at least one mode conversion unit and combining the received optical signal into a beam of optical signal.

[0019] For information on the beneficial effects of the fourth and fifth aspects, please refer to the beneficial effects of other aspects. Attached Figure Description

[0020] Figure 1 This is a block diagram of the receiver end of a silicon-based optoelectronic chip;

[0021] Figure 2 This is a schematic diagram of a wavelength division multiplexer (demultiplexer) based on a cascaded MZI structure;

[0022] Figure 3 This invention provides a schematic diagram of an optical signal receiving unit structure;

[0023] Figure 4 A curve showing the change of the equivalent refractive index of a waveguide as a function of the width sensitivity of a silicon nitride waveguide, provided by the present invention;

[0024] Figure 5 This is a schematic diagram of an embodiment of a wavelength division (demultiplexer) based on a cascaded MZI structure provided by the present invention;

[0025] Figure 6 A schematic diagram illustrating the effect of waveguide width variation of an optical waveguide delay line on the spectrum of a wavelength division (demultiplexer) in TM mode, as provided by this invention.

[0026] Figure 7 A schematic diagram illustrating the effect of waveguide width variation of an optical waveguide delay line on the spectrum of a wavelength division (demultiplexer) in TE mode, as provided by this invention.

[0027] Figure 8 A curve showing the change of the equivalent refractive index of a waveguide made of silicon material as a function of temperature sensitivity, provided for the present invention.

[0028] Figure 9 This is a schematic diagram of a silicon-based optoelectronic chip embodiment provided by the present invention;

[0029] Figure 10 A schematic diagram of another embodiment of a silicon-based optoelectronic chip provided by the present invention;

[0030] Figure 11 A schematic diagram of an optical signal transmission unit structure provided by the present invention;

[0031] Figure 12 A schematic diagram of another embodiment of a silicon-based optoelectronic chip provided by the present invention;

[0032] Figure 13 A schematic flowchart illustrating an optical signal processing method provided by the present invention;

[0033] Figure 14 This is a flowchart illustrating another optical signal processing method provided by the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of this application are described below with reference to the accompanying drawings. In the description of the embodiments of this application, the terminology used in the following embodiments is for the purpose of describing specific embodiments only and is not intended to limit the application. As used in the specification and appended claims of this application, the singular expressions "a," "the," "the," "the," and "this" are intended to also include expressions such as "one or more," unless the context clearly indicates otherwise. It should also be understood that in the following embodiments of this application, "at least one" and "one or more" refer to one or more (including two). The term "and / or" is used to describe the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0035] References to "one embodiment" or "some embodiments" in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized. The term "connection" includes direct connections and indirect connections, unless otherwise stated. "First" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0036] In the embodiments of this application, the words "exemplarily" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplarily" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of the words "exemplarily" or "for example" is intended to present the relevant concepts in a specific manner.

[0037] Figure 2An MZI structure is shown, comprising two directional couplers and two optical waveguide delay lines, namely directional coupler A201, directional coupler B202, optical waveguide delay line 203, and optical waveguide delay line 204. Optical waveguide delay lines 203 and 204 have different lengths, thereby providing a phase difference between the upper and lower arms of the MZI. Typically, the directional couplers and optical waveguide delay lines are designed using single-mode waveguides based on the TE mode. However, during fabrication, the waveguide width fluctuates within ±10% of the design value. This affects the splitting ratio of the two output ports of the directional coupler and the phase difference between the upper and lower arms of the MZI, thus degrading the overall performance of the Mux or Demux, such as reduced channel bandwidth, increased channel crosstalk, affected optical insertion loss, and shifted channel center wavelength.

[0038] To address the above problems, the present invention provides an optical signal receiving unit, such as... Figure 3 As shown, the optical signal receiving unit includes: a first edge coupler 301, a polarization processor 302, a first demultiplexer 3031, and a second demultiplexer 3032; the polarization processor 302 is used to receive the optical signal emitted by the first edge coupler 301 and convert the optical signal emitted by the first edge coupler 301 into two transmitted optical signals, and the polarization orthogonal mode of the waveguide used for transmitting the optical signal in at least one of the two transmitted optical signals is a basic transverse magnetic mode; the first demultiplexer 3031 and the second demultiplexer 3032 each include at least two transmission channels and are used to decompose the optical signal transmitted in one of the two channels into optical signals of different wavelengths.

[0039] Compared to existing technologies where all optical signals arriving at the demultiplexer are transmitted through a basic transverse electric mode (TE) waveguide, this invention ensures that at least one of the optical signals arriving at the demultiplexer is transmitted through a basic transverse magnetic mode waveguide, thus reducing process sensitivity.

[0040] In some embodiments, the polarization processor includes a polarization beamsplitter; the polarization beamsplitter is used to receive the optical signal emitted by the first edge coupler and convert the optical signal emitted by the first edge coupler into two transmitted optical signals, wherein the polarization orthogonal mode of the waveguide used for transmitting the optical signal in one of the two paths is a basic transverse magnetic mode, and the polarization orthogonal mode of the waveguide used for transmitting the optical signal in the other of the two paths is a basic transverse electric mode. By eliminating the PSR in the prior art through the polarization processor, the overall area can be reduced, which is beneficial for the miniaturization of silicon chips.

[0041] In some embodiments, the polarization processor includes a polarization beamsplitter and a polarization rotator. The polarization beamsplitter receives the optical signal emitted by the first edge coupler and converts it into two transmitted optical signals. One of the transmitted optical signals has a waveguide polarization orthogonal mode of a fundamental transverse magnetic mode, and the other has a waveguide polarization orthogonal mode of a fundamental transverse electric mode. The polarization rotator changes the polarization orthogonal mode of the waveguide in the other transmitted optical signal from the fundamental transverse electric mode to the fundamental transverse magnetic mode. By ensuring that all optical signals arriving at the demultiplexer are transmitted through waveguides in the fundamental transverse magnetic mode, process sensitivity is significantly reduced.

[0042] In some embodiments, the optical signal receiving unit further includes a photo-diode array (PDArray), which receives the optical signal emitted by the demultiplexer and converts it into photocurrent to complete the conversion from optical signal to electrical signal. The photo-diode array is also known as a PD array.

[0043] In some embodiments, the demultiplexer includes: at least one process-sensitive suppression unit, the process-sensitive suppression unit including a first directional coupler, a second directional coupler, a first optical waveguide delay line, and a second optical waveguide delay line; one end of the first optical waveguide delay line is connected to a first end of the first directional coupler, and the other end of the first optical waveguide delay line is connected to a second end of the second directional coupler; one end of the second optical waveguide delay line is connected to a third end of the first directional coupler, and the other end of the second optical waveguide delay line is connected to a fourth end of the second directional coupler. The widths of both the first and second optical waveguide delay lines are wider than the widths of delay lines in demultiplexers in the prior art. In some specific embodiments, the widths of both the first and second optical waveguide delay lines are 2 to 3 times larger than the widths of delay lines in demultiplexers in the prior art.

[0044] In some embodiments, the width of the waveguides in the first and second directional couplers ranges from 1.3 to 2.5 micrometers. Currently, the commonly used width of the waveguides in the first and second directional couplers is 0.7 to 0.8 micrometers, which has high process sensitivity. This invention reduces process sensitivity by limiting the width of the waveguides in the first and second directional couplers to a range of 1.3 to 2.5 micrometers.

[0045] For example, the relationship between the wavelength λ at the center of the Mux or Demux channel and the waveguide width w can be represented by Δλ / Δw, and the relationship between the waveguide equivalent refractive index n and the sensitivity of the silicon nitride waveguide width w can be represented by dn / dw, while Δλ / Δw ∝ dn / dw. Figure 4 Taking silicon nitride (SN) waveguides as an example, a curve showing the equivalent refractive index of the waveguide versus its width sensitivity (dn / dw) is presented. The curve shows that as the waveguide width increases, the dn / dw value decreases, indicating that the waveguide is less sensitive to width. Preferably, the waveguide width constituting the first directional coupler, the second directional coupler, the first optical waveguide delay line, and the second optical waveguide delay line is 2 micrometers. At this width, the waveguide sensitivity is very low, and the sensitivity near 2 micrometers is essentially stable. When the waveguide width is 2 micrometers, the dn / dw values ​​in TE and TM modes are essentially the same. Therefore, the MZI optical waveguide delay line can be designed with a wide waveguide to reduce its sensitivity to waveguide width. Furthermore, this invention provides a demultiplexer or wavelength division multiplexer. Taking the demultiplexer as an example, the demultiplexer includes an improved MZI, the structure of which is as follows... Figure 5 As shown, the improved MZI includes a first directional coupler 501, a second directional coupler 502, a first optical waveguide delay line 503, and a second optical waveguide delay line 504. The waveguides of the first directional coupler 501, the second directional coupler 502, the first optical waveguide delay line 503, and the second optical waveguide delay line 504 are all designed based on the TM mode, and both the first directional coupler 501 and the second directional coupler 502 include two waveguides. The width of the waveguides of the first optical waveguide delay line 503 and the second optical waveguide delay line 504 is increased by 2 to 3 times compared to the prior art. In a preferred embodiment, the width of the waveguides of the first optical waveguide delay line 503 and the second optical waveguide delay line 504 is increased by 2, 2.5, or 3 times compared to the prior art, reducing the process sensitivity of the optical waveguide delay lines in the MZI structure, and thus reducing the process sensitivity of the demultiplexer. However, because directional couplers need to consider beam splitting, the waveguides of the first directional coupler 501 and the second directional coupler 502 are generally single-mode waveguides for transmission. Therefore, the waveguide width cannot be too large. The waveguide widths of the first directional coupler 501 and the second directional coupler 502 are generally controlled between 1.3-2.5 μm. Within this waveguide width range, from Figure 4In the diagram, we can observe that the waveguide in TM mode has a smaller dn / dw ratio, meaning that the waveguide in TM mode is less sensitive to width. In some preferred embodiments, the waveguide widths of the first directional coupler 501 and the second directional coupler 502 are 1.3µm, 1.5µm, 1.7µm, 2.0µm, 2.3µm, or 2.5µm. Therefore, by designing directional couplers and optical waveguide delay lines based on TM mode MZI, and realizing TM mode Mux or Demux through cascading MZI, the impact of waveguide width fluctuations on the performance of Mux or Demux devices can be reduced. Figure 6 and Figure 7 These are the effects of changes in the waveguide width of the MZI optical waveguide delay line on the spectral center wavelength in TE and TM modes, respectively. For every 100nm increase in waveguide width, the center wavelength of the Mux or Demux spectrum will redshift by 1.5nm in TE mode and by 1nm in TM mode. Therefore, the sensitivity of the spectral center wavelength to the waveguide width will be reduced in Demux designed in TM mode.

[0046] In addition, such as Figure 8 The graph shows the equivalent refractive index of a silicon waveguide as a function of temperature sensitivity (dn / dT). It can be seen that the silicon waveguide is less sensitive to temperature in TM mode compared to TE mode. Therefore, using TM mode in a Mux or Demux design can reduce the device's temperature sensitivity. Typically, Mux or Demux incorporates thermal phase tuners in the upper and lower arms of the MZI circuit using TM mode design. Because the device's temperature sensitivity is reduced, the power consumption of the thermal phase tuner can be decreased.

[0047] Based on the optical signal receiving unit provided in any of the above embodiments, the present invention provides a silicon-based optoelectronic chip, comprising: at least one optical signal receiving unit.

[0048] To provide a more detailed description of the silicon-based optoelectronic chip provided by this invention, specific examples are given below.

[0049] Example 1:

[0050] like Figure 9As shown, this embodiment is applicable to the receiver of a silicon-based optoelectronic chip. Light in the optical fiber is coupled into the silicon photonic chip via an edge coupler C901. The optical signal is then transmitted through a waveguide containing both TE and TM modes. It is then split by a polarizing beam splitter (PS) 902 into a waveguide 9032 containing only TE mode and a waveguide 9031 containing only TM mode. After demultiplexing by demultiplexers C904 and D905 respectively, each output contains four different wavelengths of optical signal, which then enters the first PD array 906. Since the first PD array 906 can be designed to be insensitive to the polarization orthogonal modes of the waveguides, demultiplexers C and D can be designed based on TE and TM modes respectively. Compared to... Figure 1 The commonly used system shown no longer uses a PSR in its architecture. Furthermore, the PS is generally smaller and has lower insertion loss than the PSR, which facilitates device miniaturization and simplifies design. Simultaneously, the use of a TM-mode Demux reduces the device's sensitivity to process conditions and improves yield.

[0051] Example 2:

[0052] like Figure 10 As shown, this embodiment is also applicable to the receiver of a silicon-based optoelectronic chip. Compared to Embodiment 1, the two demultiplexers in this embodiment, namely demultiplexer E1006 and demultiplexer F1005, both employ waveguides designed in TM mode. Light in the optical fiber is coupled into the silicon photonic chip via edge coupler D1001. After being split by polarization beamsplitter 1002, a polarization rotator 1004 (PR) is introduced into the path containing the TE mode waveguide 1032 to convert the TE mode waveguide into a TM mode waveguide. This embodiment, compared to... Figure 1 The PS and PR work together to replace the PSR, but the overall size and design complexity are reduced. In addition, Demux, which uses the TM mode of waveguide polarization orthogonal mode, reduces the sensitivity to process technology and can improve yield.

[0053] The present invention also provides an optical signal transmitting unit. Specifically, the optical signal receiving unit described in any of the above embodiments can be used to receive an optical signal emitted by the optical signal transmitting unit. The optical signal transmitting unit, such as... Figure 11As shown, it includes: at least one mode conversion unit 1101 and a wavelength division multiplexer 1102; the mode conversion unit 1101 is used to change the polarization orthogonal mode of the waveguide transmitting the optical signal from a basic transverse electric mode to a basic transverse magnetic mode; the wavelength division multiplexer 1102 is used to receive the optical signal emitted by at least one mode conversion unit and combine the received optical signals into a single optical signal. The optical signal transmitting unit provided by this invention and the optical signal receiving unit described in any of the above embodiments belong to the same general inventive concept, both replacing the conventional technical means in the prior art, that is, waveguides that use the basic transverse electric mode to transmit optical signals, with waveguides that use the basic transverse magnetic mode to transmit optical signals.

[0054] In some embodiments, the mode conversion unit includes: a light source, a second edge coupler, an electro-optic modulator, and a polarization rotator; the light source is used to emit an optical signal; the second edge coupler is used to receive the optical signal emitted by the light source and transmitted through a waveguide whose polarization orthogonality mode is a basic transverse electric mode; the electro-optic modulator is used to electro-optically modulate the optical signal emitted by the second edge coupler; the polarization rotator is used to receive the optical signal emitted by the second edge coupler after being modulated by the electro-optic modulator, and is used to change the polarization orthogonality mode of the waveguide transmitting the optical signal from a basic transverse electric mode to a basic transverse magnetic mode.

[0055] The optical signal transmitting unit can also constitute another embodiment of a silicon-based optoelectronic chip, specifically:

[0056] Example 3:

[0057] like Figure 12 As shown, this embodiment is applicable to the transmitting end of a silicon-based optoelectronic chip. The silicon-based optoelectronic chip includes a first light source 1201, a second light source 1202, a third light source 1203, a fourth light source 1204, an edge coupler E1205, an edge coupler F1206, an edge coupler G1207, an edge coupler H1208, a first electro-optic modulator 1209, a second electro-optic modulator 1210, a third electro-optic modulator 1211, a fourth electro-optic modulator 1212, a polarization rotator A1213, and a polarization selector. The device comprises a polarization selector B1214, a polarization rotator C1215, a polarization rotator D1216, and a wavelength division multiplexer 1217. The wavelength division multiplexer 1217 acquires four transmitted optical signals composed of the above-mentioned devices. The waveguide of the wavelength division multiplexer 1217 is designed in TM mode. The polarization rotator A1213, polarization selector B1214, polarization rotator C1215, and polarization rotator D1216 respectively change the transmission waveguide of the optical signal sent through the corresponding electro-optic modulator from TE mode to TM mode.

[0058] The waveguides used in any embodiment of the present invention include, but are not limited to, silicon waveguides, silicon nitride waveguides, silicon oxynitride waveguides, lithium niobate waveguides, indium phosphide waveguides, alumina waveguides, polymer waveguides, or other waveguides with a refractive index higher than that of silicon oxide.

[0059] The MZI structure proposed in this invention can be applied not only to wavelength division multiplexers or demultiplexers, but also to other applications, including but not limited to tunable filters, laser resonant cavities, and dispersion compensators.

[0060] Based on the optical signal receiving unit provided in any of the above embodiments, the present invention provides a method for processing optical signals, such as... Figure 13 As shown, it includes:

[0061] S1301. Provide the optical signal receiving unit, the optical signal receiving unit including a first edge coupler, a pair of demultiplexers and a polarization processor;

[0062] S1302, The polarization processor receives the optical signal emitted by the first edge coupler and converts the optical signal emitted by the first edge coupler into two transmitted optical signals, and the polarization orthogonal mode of the waveguide used for transmitting the optical signal in at least one of the two transmitted optical signals is the basic transverse magnetic mode.

[0063] S1303 The demultiplexer includes at least two transmission channels and decomposes the optical signal transmitted by one of the two channels into optical signals of different wavelengths.

[0064] Based on the optical signal transmitting unit provided in any of the above embodiments, the present invention provides an optical signal processing method, such as... Figure 14 As shown, it includes:

[0065] S1401. Provide the optical signal transmission unit, the optical signal transmission unit including at least one mode conversion unit and a wavelength division multiplexer;

[0066] S1402, The mode conversion unit changes the polarization orthogonal mode of the waveguide transmitting the optical signal from the basic transverse electric mode to the basic transverse magnetic mode.

[0067] S1403 The wavelength division multiplexer receives optical signals emitted by at least one mode conversion unit and combines the received optical signals into a single optical signal.

[0068] The above description is merely a specific implementation of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the embodiments of this application should be covered within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be determined by the protection scope of the claims.

Claims

1. An optical signal receiving unit, characterized in that, include: A first edge coupler, a pair of demultiplexers, and a polarization processor; The polarization processor is used to receive the optical signal emitted by the first edge coupler and convert the optical signal emitted by the first edge coupler into two transmitted optical signals, wherein the polarization orthogonal mode of the waveguide used for transmitting the optical signal in at least one of the two transmitted optical signals is the basic transverse magnetic mode. The demultiplexer includes at least two transmission channels and is used to decompose the optical signal transmitted in one of the two channels into optical signals of different wavelengths. The demultiplexer further includes: at least one process-sensitive suppression unit, the process-sensitive suppression unit including a first directional coupler, a second directional coupler, a first optical waveguide delay line, and a second optical waveguide delay line; One end of the first optical waveguide delay line is connected to the first end of the first directional coupler, and the other end of the first optical waveguide delay line is connected to the second end of the second directional coupler. One end of the second optical waveguide delay line is connected to the third end of the first directional coupler, and the other end of the second optical waveguide delay line is connected to the fourth end of the second directional coupler.

2. The optical signal receiving unit according to claim 1, characterized in that, The polarization processor includes: a polarization beam splitter; The polarization beam splitter is used to receive the optical signal emitted by the first edge coupler and convert the optical signal emitted by the first edge coupler into two transmitted optical signals. The polarization orthogonal mode of the waveguide used for transmitting the optical signal on one of the two paths is a basic transverse magnetic mode, and the polarization orthogonal mode of the waveguide used for transmitting the optical signal on the other path is a basic transverse electric mode.

3. The optical signal receiving unit according to claim 1, characterized in that, The polarization processor includes: a polarization beam splitter and a polarization rotator; The polarization beam splitter is used to receive the optical signal emitted by the first edge coupler and convert the optical signal emitted by the first edge coupler into two transmitted optical signals. The polarization orthogonal mode of the waveguide used for transmitting the optical signal on one of the two paths is a basic transverse magnetic mode, and the polarization orthogonal mode of the waveguide used for transmitting the optical signal on the other path is a basic transverse electric mode. The polarization rotator is used to change the polarization orthogonal mode of the waveguide used for transmitting optical signals on the other of the two paths from the basic transverse electric mode to the basic transverse magnetic mode.

4. The optical signal receiving unit according to claim 2 or 3, characterized in that, Also includes: A photoelectric detection array is used to receive the optical signal emitted by the demultiplexer and convert it into photocurrent to complete the conversion from optical signal to electrical signal.

5. The optical signal receiving unit according to claim 1, characterized in that, The width of the waveguide in the first directional coupler and the second directional coupler ranges from 1.3 to 2.5 micrometers.

6. The optical signal receiving unit according to claim 1, characterized in that, The width of the waveguide in the first and second optical waveguide delay lines ranges from 1.3 to 2.5 micrometers.

7. A method for processing optical signals, characterized in that, The optical signal receiving unit applied to any one of claims 1-6 comprises: The optical signal receiving unit is provided, the optical signal receiving unit including a first edge coupler, a pair of demultiplexers and a polarization processor; The polarization processor receives the optical signal emitted by the first edge coupler and converts the optical signal emitted by the first edge coupler into two transmitted optical signals, wherein the polarization orthogonal mode of the waveguide used for transmitting the optical signal in at least one of the two transmitted optical signals is the basic transverse magnetic mode. The demultiplexer includes at least two transmission channels and decomposes the optical signal transmitted by one of the two channels into optical signals of different wavelengths; The demultiplexer further includes: at least one process-sensitive suppression unit, the process-sensitive suppression unit including a first directional coupler, a second directional coupler, a first optical waveguide delay line, and a second optical waveguide delay line; One end of the first optical waveguide delay line is connected to the first end of the first directional coupler, and the other end of the first optical waveguide delay line is connected to the second end of the second directional coupler. One end of the second optical waveguide delay line is connected to the third end of the first directional coupler, and the other end of the second optical waveguide delay line is connected to the fourth end of the second directional coupler.

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