Bidirectionally adjustable thermo-optical phase shifter and its network structure

Abstract

The present invention provides a bidirectionally adjustable thermo-optical phase shifter and its network structure, the thermo-optical phase shifter comprises: at least two optical waveguide structures, at least two temperature adjustment units, a first electrical port and a second electrical port, the temperature adjustment units are arranged one by one above or on both sides of the optical waveguide structure; the temperature adjustment unit comprises: a PN junction and a metal heating unit connected in series; the PN junction in at least one temperature adjustment unit is arranged inversely to the PN junctions in the remaining temperature adjustment units and is connected to the first electrical port, and the metal heating units in all temperature adjustment units are connected to the second electrical port. The bidirectionally adjustable thermo-optical phase shifter and its network structure of the present invention can realize bidirectional adjustment of the phase difference of the optical waveguide structure without increasing the electrical ports, thereby effectively reducing the power consumption of the thermo-optical phase shifter; in addition, the number of electrical ports of the network structure based on the bidirectionally adjustable thermo-optical phase shifter is greatly reduced, while improving the process tolerance.

Description

Technical Field

[0001] The invention relates to the technical field of thermo-optic phase shifters, and in particular to a bidirectionally adjustable thermo-optic phase shifter and a network structure thereof. Background Art

[0002] With the development of semiconductor technology, the size of chips has been reduced to the limit. In order to further develop chips with higher performance and break Moore's Law, silicon-based optoelectronic chips that can improve device performance without reducing the size of the device have come into being. Silicon-based optoelectronic chips generally modulate the intensity, amplitude, frequency, phase, polarization, and propagation direction of light through electro-optics, thermo-optics, and acousto-optics. Among them, thermo-optic phase shifters that use thermo-optics to achieve optical phase changes are a commonly used functional device in silicon-based chips.

[0003] At present, the MZI structure composed of thermo-optical phase shifters has been applied to the topology of optical switch arrays of photonic integrated devices and networks such as photonic artificial intelligence. In these networks, MZI is designed as an equal-arm structure, which can ensure the large bandwidth of the network and the optical transmission rate in a 2P π The phase and power can be adjusted within the power consumption range. However, in the actual production process, the two arms of the MZI are often unequal due to process uncertainty, that is, the initial phase difference of the light after passing through the MZI is not at 0 phase, such as Figure 1 The example shown is used to illustrate, Figure 1 The MZI actually made in the experiment has an initial phase difference of 0π instead of 0 after the light passes through the MZI. At this time, for the traditional thermo-optic phase shifter, whether it is positive pressure or negative pressure, since the phase can only move in one direction, when the traditional thermo-optic phase shifter is needed to achieve a phase difference of 0.3π after the light passes through the MZI, due to the unidirectionality of its phase shift, the traditional thermo-optic phase shifter needs to first shift the phase to 2π and then continue to 2.3π to achieve a phase change of 0.3π. This process requires a voltage of about 6.5V to achieve, which will greatly increase the power consumption of the thermo-optic phase shifter.

[0004] In addition, the currently commonly used thermo-optical phase shifters require at least two electrical input / output (IO) ports for control. If bidirectional adjustable phase of the thermo-optical phase shifter is required, three electrical input / output ports are required. When such thermo-optical phase shifters are used as unit devices in network structures such as optical switch topologies and photonic artificial intelligence, the number of electrical ports will increase rapidly with the increase in the number of phase shifters, which greatly increases the difficulty and cost of device electrical packaging, and also limits the scale expansion of network structures based on thermo-optical phase shifters.

[0005] In summary, how to provide a thermo-optical phase shifter and a network structure thereof to reduce the power consumption of the thermo-optical phase shifter and reduce the number of electrical ports of the thermo-optical phase shifter network structure is a technical problem that currently needs to be solved urgently by those skilled in the art. Summary of the invention

[0006] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a bidirectionally adjustable thermo-optical phase shifter and its network structure, so as to solve the problems of high power consumption of the thermo-optical phase shifter in the prior art, unstable resistance of the temperature adjustment unit during actual operation, and a large number of electrical ports in the network structure based on the thermo-optical phase shifter.

[0007] In order to achieve the above-mentioned object and other related objects, the present invention provides a bidirectionally adjustable thermo-optical phase shifter, the thermo-optical phase shifter comprising:

[0008] At least two optical waveguide structures, at least two temperature adjustment units, a first electrical port and a second electrical port, wherein the temperature adjustment units are arranged one by one above or on both sides of the optical waveguide structures, and the temperature adjustment units are used to adjust the phase of the light wave guided by the corresponding optical waveguide structures;

[0009] The temperature adjustment unit comprises: a PN junction and a metal heating unit connected in series;

[0010] The PN junction in at least one of the temperature adjustment units is arranged inversely to the PN junctions in the remaining temperature adjustment units and are connected to the first electrical port in common, and the metal heating units in all the temperature adjustment units are connected to the second electrical port in common.

[0011] Optionally, the resistance of the PN junction and the metal heating unit connected in series satisfies the relationship R 01 / R 02 =C2 / C1, where R 01 is the initial resistance value of the PN junction, R 02 is the initial resistance value of the metal heating unit, C1 is the resistance temperature coefficient of the PN junction, and C2 is the resistance temperature coefficient of the metal heating unit.

[0012] Optionally, the substrate material of the bidirectionally adjustable thermo-optical phase shifter includes semiconductor material or polymer material.

[0013] Optionally, the PN junction includes a PN junction formed by a P-type doped waveguide and an N-type doped waveguide or a PN junction formed by a P-type semiconductor and an N-type semiconductor.

[0014] Optionally, the PN junction is composed of more than two sub-PN junctions, and all the sub-PN junctions are connected to each other in series or in parallel.

[0015] Optionally, the material of the metal heating unit includes TiN, W or Cu.

[0016] Optionally, the metal heating unit is composed of more than two sub-metal heating units, and all the sub-metal heating units are connected to each other in series, or in parallel, or in a combination of series and parallel.

[0017] Optionally, the metal heating unit and the PN junction are connected in series via a through silicon via structure or a metal lead; the metal heating unit and the second electrical port are connected via a metal lead or a direct connection.

[0018] Optionally, the initial phase difference of all the optical waveguide structures is between 0 and 2π.

[0019] The present invention also provides a network structure of a bidirectionally adjustable thermo-optic phase shifter, which includes more than two bidirectionally adjustable thermo-optic phase shifters as described above, and the metal heating units of all the bidirectionally adjustable thermo-optic phase shifters are connected to the same second electrical port.

[0020] As described above, the bidirectionally adjustable thermo-optical phase shifter and its network structure of the present invention can realize bidirectional adjustment of the phase difference of the optical waveguide structure without increasing the number of electrical ports by respectively arranging temperature adjustment units on at least two optical waveguide structures, and making a PN junction in the temperature adjustment unit on at least one optical waveguide structure that is arranged in the opposite direction to the temperature adjustment units on the other optical waveguide structures, and using two electrical ports to realize the control of at least two temperature adjustment units, thereby effectively reducing the power consumption of the thermo-optical phase shifter; in addition, the number of electrical ports of the network structure based on the bidirectionally adjustable thermo-optical phase shifter is greatly reduced, and the process tolerance is improved; furthermore, it is ensured that during the operation of the thermo-optical phase shifter, the resistance of the temperature adjustment unit will not change with the change of temperature, thereby increasing the precision and accuracy of phase adjustment and reducing the difficulty of control circuit design. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A graph showing the relationship between phase change and voltage of a conventional thermo-optical phase shifter is shown.

[0022] Figure 2 It is a schematic structural diagram showing the application of the bidirectionally adjustable thermo-optical phase shifter of the present invention to the MZI structure.

[0023] Figure 3a Shown is an equivalent circuit diagram of the bidirectionally adjustable thermo-optical phase shifter of the present invention, which includes two temperature adjustment units.

[0024] Figure 3bShown is an equivalent circuit diagram of the bidirectionally adjustable thermo-optical phase shifter of the present invention, which includes three temperature adjustment units.

[0025] Figure 3c Shown is an equivalent circuit diagram of the bidirectionally adjustable thermo-optical phase shifter of the present invention, which includes four temperature adjustment units.

[0026] Figure 4 FIG. 3 is an equivalent circuit diagram of a first implementation of a temperature adjustment unit of a bidirectionally adjustable thermo-optical phase shifter.

[0027] Figure 5 The equivalent circuit diagram of the second implementation of the temperature adjustment unit of the bidirectionally adjustable thermo-optical phase shifter in FIG. 3 is shown.

[0028] Figure 6 The equivalent circuit diagram of the third implementation of the temperature adjustment unit of the bidirectionally adjustable thermo-optical phase shifter in FIG. 3 is shown.

[0029] Figure 7 It is a schematic diagram showing a voltage regulation method for realizing different phase changes of the bidirectionally adjustable thermo-optical phase shifter of the present invention.

[0030] Figure 8 It shows the relationship between the phase change and the voltage of the bidirectionally adjustable thermo-optical phase shifter of the present invention.

[0031] Fig. 9 The bidirectionally adjustable thermo-optical phase shifter according to the present invention is shown in FIG. π A curve showing the relationship between the phase change and voltage size of the optical switch achieved within / 2 power consumption.

[0032] Fig.10 It shows a 1×N network structure formed by the bidirectionally adjustable thermo-optical phase shifter based on the present invention.

[0033] Fig.11 It shows a 1×2 network structure formed by the bidirectionally adjustable thermo-optical phase shifter based on the present invention.

[0034] Fig.12 Display as Fig.11 A schematic diagram of a voltage regulation method based on a 1×2 network structure formed by the bidirectionally adjustable thermo-optical phase shifter of the present invention.

[0035] Fig.13 It shows the relationship between the phase change and the voltage of the bidirectionally adjustable thermo-optical phase shifter of the present invention.

[0036] Component number description

[0037] 10 Optical structure

[0038] 11 Optical waveguide structure

[0039] 12 Temperature Control Unit

[0040] 13 Metal Heating Unit

[0041] 14 PN junction

[0042] 15 Sub-metal heating unit

[0043] 16 Sub-PN junction

[0044] 17 P-junction

[0045] 18 N-type junction

[0046] 19 First electrical port

[0047] 20 Second electrical port

[0048] 21 Metal lead

[0049] 22 Bidirectionally adjustable thermo-optical phase shifter DETAILED DESCRIPTION

[0050] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0051] See also Figures 1 to 12 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0052] Embodiment 1

[0053] like Figure 2 As shown in FIG3 , this embodiment provides a bidirectionally adjustable thermo-optical phase shifter, the thermo-optical phase shifter comprising:

[0054] At least two optical waveguide structures 11, at least two temperature adjustment units 12, a first electrical port 19 and a second electrical port 20, wherein the temperature adjustment units 12 are arranged one by one above or on both sides of the optical waveguide structure 11, and the temperature adjustment units 12 are used to adjust the phase of the light wave guided by the corresponding optical waveguide structure 11;

[0055] The temperature adjustment unit 12 includes: a PN junction 14 and a metal heating unit 13 connected in series;

[0056] The PN junction 14 in at least one of the temperature regulating units 12 is arranged inversely to the PN junctions 14 in the remaining temperature regulating units 12 and are connected to the first electrical port 19 , and the metal heating units 13 in all the temperature regulating units 12 are connected to the second electrical port 20 .

[0057] In this embodiment, the number of the optical waveguide structure 11 and the temperature adjustment unit 12 is not limited, as long as it is greater than two, for example Figure 3a There are two optical waveguide structures 11 and two temperature adjustment units 12, Figure 3b There are three optical waveguide structures 11 and three temperature adjustment units 12 shown. Figure 3c There are four optical waveguide structures 11 and four temperature adjustment units 12, and other numbers are also possible, which are not limited here and are set according to specific circumstances. In addition, in this embodiment, as long as at least one PN junction of the PN junctions 14 of all the temperature adjustment units 12 is set in the opposite direction to the other PN junctions, for example Figure 3a shows two PN junctions arranged in opposite directions, Figure 3b Shows a PN junction that is set inversely to the other two PN junctions. Figure 3c It is shown that two PN junctions are arranged inversely to the other two PN junctions, and other reverse arrangements are also possible, which are not limited here and are arranged according to specific circumstances.

[0058] The bidirectionally adjustable thermo-optical phase shifter of the present embodiment is configured by respectively setting temperature adjustment units on at least two optical waveguide structures, and making a PN junction 14 in the temperature adjustment unit 12 on at least one optical waveguide structure 11 that is set in the opposite direction to the temperature adjustment units 12 on the other optical waveguide structures 11, and using two electrical ports to realize control of at least two temperature adjustment units. It is possible to realize bidirectional adjustment of the phase difference of the optical waveguide structure 11 without increasing the number of electrical ports, thereby effectively reducing the power consumption of the thermo-optical phase shifter.

[0059] by Figure 2The bidirectional adjustable thermo-optical phase shifter based on the MZI structure shown is taken as an example to illustrate the power consumption reduction effect of the present embodiment. A P-type junction 17 is formed by a P-type doped waveguide structure and an N-type junction 18 is formed by an N-type doped waveguide structure. The P-type junction 17 and the N-type junction 18 respectively form two PN junctions 14 in opposite directions in the temperature adjustment unit 12 on the two optical waveguide structures 11 of the two arms of the MZI. Since the PN junction has the characteristics of forward conduction and reverse cutoff, and the phase change of the thermo-optical phase shifter of the MZI structure is mainly formed by the phase difference of the optical waveguide structures 11 of the two arms, the positive and negative changes of the phase difference between the two arms of the MZI can be achieved by heating the two arms of the MZI by changing the positive and negative voltage difference between the first electrical port 19 and the second electrical port 20 (the first electrical port and the second electrical port are generally referred to as electrical output and input I / O ports). When the voltage of the first electrical port 19 is greater than the voltage of the second electrical port 20, the PN junction in the temperature regulating unit 12 at the upper end of the MZI is turned on, and the PN junction in the temperature regulating unit 12 at the lower end of the MZI is turned off, then only the temperature regulating unit 12 at the upper end of the MZI works, causing the refractive index of the upper arm optical waveguide structure to change, causing the phase of light passing through the upper arm optical waveguide structure to change; when the voltage of the first electrical port 19 is less than the voltage of the second electrical port 20, the PN junction in the temperature regulating unit 12 at the lower end of the MZI is turned on, and the PN junction in the temperature regulating unit 12 at the upper end of the MZI is turned off, then only the temperature regulating unit 12 at the lower end of the MZI works, causing the refractive index of the lower arm optical waveguide structure to change, causing the phase of light passing through the lower arm optical waveguide structure to change. Take the actual MZI obtained after the initial phase of light passing through the MZI as 0.5π for illustration, when a thermo-optical phase shifter is required to realize that the phase of the MZI after the light passes through the MZI is 0, such as Fig.13 As shown, since the thermo-optical phase shifter of this embodiment can realize bidirectional adjustment, only 0.5P π The power consumption can be achieved; Figure 1 As shown, the use of traditional thermo-optical phase shifters requires 1.5*P due to the unidirectional nature of the phase shift. π Therefore, the use of the thermo-optical phase shifter of this embodiment can save P π Taking the example in the background technology, when a thermo-optical phase shifter is required to achieve a phase of 0.3π after light passes through the MZI, Fig.13 As shown, the thermo-optical phase shifter of this embodiment only needs 0.2*P π The power consumption can be reduced by about -2.5V voltage. Figure 1 As shown, the conventional thermo-optical phase shifter requires 1.8*P π The power consumption can be reduced by about 6.5V voltage, so the thermo-optical phase shifter of this embodiment can save 1.6*P πIn addition, when one of the temperature adjustment units fails, the operation of the other temperature adjustment unit will not be affected by the thermo-optical phase shifter of this embodiment. At this time, the thermo-optical phase shifter can still work, which effectively improves the process tolerance of the device.

[0060] As an example, the substrate material for preparing the bidirectionally adjustable thermo-optical phase shifter of this embodiment can be any suitable material selected according to the specific situation, for example, semiconductors such as silicon dioxide, silicon, silicon nitride, SOI and III-V compounds, and polymers can be selected.

[0061] As an example, the optical waveguide structure 11 includes but is not limited to single-mode waveguides and multi-mode waveguides commonly used in photon integration, and the width and height of the waveguide can be arbitrarily designed as needed. Preferably, the optical waveguide structure 11 includes a strip waveguide, a ridge waveguide, a slab waveguide, etc. More preferably, the optical waveguide structure 11 includes a step-type and a gradient waveguide structure.

[0062] As an example, the form of the PN junction 14 can be any suitable form, which is specifically set according to actual needs. Preferably, the PN junction 14 can be a PN junction composed of a waveguide with P-type doping and N-type doping or a PN junction composed of a P-type semiconductor and an N-type semiconductor. The doping form of the PN junction 14 includes but is not limited to light doping, heavy doping or mixed doping.

[0063] like Figures 4 to 6 As shown, as an example, the PN junction 14 is composed of more than two sub-PN junctions 16 (such as Figures 4 to 6 2 sub-PN junctions are shown in FIG. 1 ), and all the sub-PN junctions 16 are connected in series (such as Figure 4 as shown) or connected in parallel with each other (as shown Figure 6 shown).

[0064] like Figures 4 to 6 As shown, as an example, the metal heating unit 13 is composed of more than two sub-metal heating units 15, and all the sub-metal heating units 15 are connected to each other in series (such as Figure 4 ), or connected in parallel (as shown in Figure 5 ), or connected in series and parallel (as shown in Figure 6 shown).

[0065] As an example, the material of the metal heating unit 13 may be a metal material with a certain resistance, such as but not limited to a combination of one or more of TiN, W, and Cu. In this embodiment, TiN or W is preferred.

[0066] As an example, the relative position relationship between the metal heating unit 13 and the optical waveguide structure 11 can be selected in any suitable existing distribution mode, such as but not limited to vertical distribution, horizontal distribution or spaced arrangement.

[0067] As an example, the series connection of the metal heating unit 13 and the PN junction 14 includes but is not limited to series connection through a through silicon via structure, or through a metal lead 21; the connection of the metal heating unit 13 and the second electrical port 20 includes but is not limited to connection through a metal lead 21, or connection through a direct connection. Preferably, the first electrical port 19, the second electrical port 20 and the metal lead 21 are made of metal materials with low resistance, such as gold, copper, aluminum or titanium alloy.

[0068] As an example, the initial phase difference of all the optical waveguide structures 11 may be any phase between 0 and 2π.

[0069] like Figure 7 As shown, as an example, a voltage regulation method for realizing different phase changes of the bidirectionally adjustable thermo-optical phase shifter of this embodiment is illustrated, the second electrical port 20 (i.e., the electrical I port) is set to the reference 0 voltage position, and then the phase of the thermo-optical phase shifter can be arbitrarily adjusted between [-π, π] by changing the duration of the voltage applied to the first electrical port 19 (i.e., the electrical O port). Figure 7 A time sequence in the figure represents the time required for the phase shifter to change by π or -π. When the duration of the voltage is 1 / 2 of the entire time sequence, the phase change is π / 2 or -π / 2. This characteristic of the bidirectionally adjustable thermo-optical phase shifter is of great significance for using an algorithm to adjust the phase of the phase shifter. In addition, the phase adjustment of the thermo-optical phase shifter can also be achieved by changing the voltage of the first electrical port 19 (i.e., the electrical O port), such as Figure 8 A curve diagram showing the relationship between the phase change and voltage magnitude of the bidirectionally adjustable thermo-optical phase shifter of this embodiment is shown. According to the Joule effect of resistance, we can know that different voltages can generate different amounts of heat at both ends of the metal heating unit, thereby causing different phase changes of the thermo-optical phase shifter.

[0070] The bidirectionally adjustable thermo-optic phase shifter of this embodiment can be applied to an MZI structure with equal arm design to reduce power consumption. Similarly, for some special application scenarios, the initial phase of the thermo-optic phase shifter can be specially designed to reduce the power consumption of the device, such as Fig. 9As shown, it is a curve diagram of the relationship between the phase change and voltage of a low-power optical switch. The initial phase difference between the two arms of the MZI is designed to be 0.5π. Then, when a positive voltage plus a power consumption of 0.5Pπ is passed through the first electrical port 19 (i.e., the electrical O port), the phase difference can be adjusted to π to achieve a closed state; when a negative voltage plus a power consumption of 0.5Pπ is passed through the first electrical port 19 (i.e., the electrical O port), the phase difference can be adjusted to 0 to achieve an open state.

[0071] As an example, in this embodiment, the resistance of the temperature adjustment unit 12 is set not to change with temperature, so as to improve the accuracy and phase adjustment precision of the temperature adjustment unit 12, which is of great significance for using algorithms to adjust the arbitrary phases of different thermo-optical phase shifters. Since semiconductors have a negative temperature coefficient of resistance, the resistance decreases with the increase of temperature; on the contrary, metals have a positive temperature coefficient of resistance, and the resistance increases with the increase of temperature. Therefore, the actual resistance R2 of the metal heating unit 13 connected in series and the actual resistance R1 of the PN junction 14 in this embodiment can be expressed as:

[0072] R1=R01*(1+C1t); R2=R02*(1+C2t)

[0073] Among them, R01 and R02 represent the initial resistance values ​​of the PN junction and the metal heating unit respectively, C1 is the resistance temperature coefficient of the PN junction, C2 is the resistance temperature coefficient of the metal heating unit, and t represents the temperature.

[0074] The two actual resistors and can be expressed as:

[0075] R1+R2=R01+R01C1t+R02+R02C2t=(R01+R02)+(R01C1t+R02C2t)

[0076] In order to ensure that the resistance of the temperature adjustment unit in the thermo-optical phase shifter remains unchanged during operation, it is only necessary to keep (R01C1t+R02C2t) unchanged. Therefore, the initial resistance value of the PN junction and the metal heating unit only needs to satisfy R01 / R02=C2 / C1 to achieve that the resistance of the temperature adjustment unit 12 does not change with temperature.

[0077] Embodiment 2

[0078] This embodiment provides a network structure of bidirectionally adjustable thermo-optic phase shifters, which is based on the bidirectionally adjustable thermo-optic phase shifters described in Embodiment 1, and includes two or more bidirectionally adjustable thermo-optic phase shifters 22 as described in Embodiment 1, and the metal heating units 15 of all the bidirectionally adjustable thermo-optic phase shifters 22 are connected to the same second electrical port 20. The thermo-optic phase shifters in the network structure can be adjusted one by one through an algorithm, thereby reducing the number of electrical ports of the network from 2N+1 to N+1, which will be of great significance in large-scale photonic integrated networks, reducing the difficulty and cost of device electrical packaging, and facilitating large-scale integration of network structures.

[0079] like Fig.10 As shown, it is a 1×N network structure formed by the bidirectionally adjustable thermo-optical phase shifter 22 according to the first embodiment. Fig.11 As shown, a 1×2 network structure formed by the bidirectionally adjustable thermo-optical phase shifter 22 according to the first embodiment is shown. Taking the 1×2 network structure as an example, the 1×2 network structure is adopted. Figure 7 Similar to the voltage regulation method, the phase of any phase shifter in the network structure can be adjusted by changing the duty cycle of the phase shifter voltage control signal, that is, the duration of the high level. In addition, if a temperature adjustment unit 12 in the network does not work due to process errors, the phase change of 2π can be achieved by heating only other temperature adjustment units 12. This feature is of great significance for improving the process tolerance of large-scale photonic integrated networks based on thermo-optical phase shifters.

[0080] In summary, the bidirectionally adjustable thermo-optical phase shifter and its network structure of the present invention can realize bidirectional adjustment of the phase difference of the optical waveguide structure without increasing the number of electrical ports by respectively setting temperature adjustment units on at least two optical waveguide structures, and making a PN junction in the temperature adjustment unit on at least one optical waveguide structure that is set in the opposite direction to the temperature adjustment units on the other optical waveguide structures, and using two electrical ports to realize the control of at least two temperature adjustment units, thereby effectively reducing the power consumption of the thermo-optical phase shifter; in addition, the number of electrical ports of the network structure based on the bidirectionally adjustable thermo-optical phase shifter is greatly reduced, and the process tolerance is improved; furthermore, it is ensured that during the operation of the thermo-optical phase shifter, the resistance of the temperature adjustment unit will not change with the change of temperature, thereby increasing the precision and accuracy of phase adjustment and reducing the difficulty of control circuit design. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0081] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A bidirectionally adjustable thermo-optical phase shifter, characterized in that: The thermo-optical phase shifter comprises: At least two optical waveguide structures, at least two temperature adjustment units, a first electrical port and a second electrical port, wherein the temperature adjustment units are arranged one by one above or on both sides of the optical waveguide structures, and the temperature adjustment units are used to adjust the phase of the light wave guided by the corresponding optical waveguide structures; The temperature adjustment unit comprises: a PN junction and a metal heating unit connected in series; The PN junction and the metal heating unit in the same temperature adjustment unit are arranged above or on both sides of the same optical waveguide structure, and the PN junction is used to turn on or off the metal heating unit in the same temperature adjustment unit, and does not have any regulating effect on the optical waveguide structure; The PN junction in at least one of the temperature adjustment units is arranged inversely to the PN junctions in the remaining temperature adjustment units and are commonly connected to the first electrical port, and the metal heating units in all the temperature adjustment units are commonly connected to the second electrical port. By changing the positive and negative voltage difference between the first electrical port and the second electrical port, the optical waveguide structure is heated to change the positive and negative changes of the phase difference between the corresponding optical waveguide structures, thereby realizing bidirectional adjustment of the phase difference of the optical waveguide structure.

2. The bidirectionally adjustable thermo-optical phase shifter according to claim 1, characterized in that: The resistance of the PN junction and the metal heating unit connected in series satisfies the relationship R 01 / R 02 =C2 / C1, where R 01 is the initial resistance value of the PN junction, R 02 is the initial resistance value of the metal heating unit, C1 is the resistance temperature coefficient of the PN junction, and C2 is the resistance temperature coefficient of the metal heating unit.

3. The bidirectionally adjustable thermo-optical phase shifter according to claim 1, characterized in that: The substrate material of the bidirectionally adjustable thermo-optical phase shifter includes semiconductor material or polymer material.

4. The bidirectionally adjustable thermo-optical phase shifter according to claim 1, characterized in that: The PN junction includes a PN junction formed by a P-type doped waveguide and an N-type doped waveguide or a PN junction formed by a P-type semiconductor and an N-type semiconductor.

5. The bidirectionally adjustable thermo-optical phase shifter according to claim 1, characterized in that: The PN junction is composed of more than two sub-PN junctions, and all the sub-PN junctions are connected in series or in parallel.

6. The bidirectionally adjustable thermo-optical phase shifter according to claim 1, characterized in that: The material of the metal heating unit includes TiN, W or Cu.

7. The bidirectionally adjustable thermo-optical phase shifter according to claim 1, characterized in that: The metal heating unit is composed of more than two sub-metal heating units, and all the sub-metal heating units are connected to each other in series, or in parallel, or in a combination of series and parallel.

8. The bidirectionally adjustable thermo-optical phase shifter according to claim 1, characterized in that: The metal heating unit is connected in series with the PN junction via a through silicon via structure or a metal lead; the metal heating unit is connected to the second electrical port via a metal lead or a direct connection.

9. The bidirectionally adjustable thermo-optical phase shifter according to claim 1, characterized in that: The initial phase differences of all the optical waveguide structures are between 0 and 2π.

10. A network structure of a bidirectionally adjustable thermo-optical phase shifter, characterized in that: The network structure comprises two or more bidirectionally adjustable thermo-optical phase shifters according to any one of claims 1 to 9, and the metal heating units of all the bidirectionally adjustable thermo-optical phase shifters are connected to the same second electrical port.

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