阅读说明：本技术 一种基于模式混合原理的w型硅基槽式片上偏振旋转器 (W-shaped silicon groove type on-chip polarization rotator based on mode mixing principle ) 是由 惠战强 攀登 文习建 于 2020-12-21 设计创作，主要内容包括：本发明公开了一种基于模式混合原理的W型硅基槽式片上偏振旋转器,属于光纤通信技术领域。该偏振旋转器包括：衬底,衬底由二氧化硅组成,在衬底的顶部设置有一段条形波导,形成偏振旋转区域；条形波导包括：W型沟槽波导、左侧阶梯型波导和右侧阶梯型波导,左侧阶梯型波导和右侧阶梯型波导分别连接在W型沟槽波导的两侧；W型沟槽波导由二氧化硅组成,左侧阶梯型波导和右侧阶梯型波导均由材料硅组成。在本发明中的偏振旋转器在300nm(1400nm-1700nm)波长范围内,对于入射光(TE/TM基模)在全波段范围内插入损耗IL＜0.4dB,模式光从input端口输入,从output端口输出,同时偏振旋转效率PCE在全波段范围内高于98.6％,1550nm中心波长处IL小于0.23dB,PCE高于99.96％。(The invention discloses a W-shaped silicon-based groove type on-chip polarization rotator based on a mode mixing principle, and belongs to the technical field of optical fiber communication. The polarization rotator includes: the substrate consists of silicon dioxide, a section of strip waveguide is arranged at the top of the substrate to form a polarization rotation area; the strip waveguide includes: the waveguide structure comprises a W-shaped groove waveguide, a left stepped waveguide and a right stepped waveguide, wherein the left stepped waveguide and the right stepped waveguide are respectively connected to two sides of the W-shaped groove waveguide; the W-shaped groove waveguide is composed of silicon dioxide, and the left stepped waveguide and the right stepped waveguide are both composed of silicon. In the invention, the polarization rotator has the insertion loss IL of less than 0.4dB in the whole wave band range for incident light (TE/TM fundamental mode) in the wavelength range of 300nm (1400nm-1700nm), mode light is input from an input port and output from an output port, meanwhile, the polarization rotation efficiency PCE is higher than 98.6% in the whole wave band range, IL is less than 0.23dB at the central wavelength of 1550nm, and PCE is higher than 99.96%.)

1. A W-type silicon trench-based on-chip polarization rotator based on a mode mixing principle, the polarization rotator comprising: the polarization rotation device comprises a substrate (1), wherein the substrate (1) is made of silicon dioxide, and a section of strip waveguide (2) is arranged at the top of the substrate (1) to form a polarization rotation region;

the strip waveguide (2) comprises: the waveguide comprises a W-shaped groove waveguide (3), a left stepped waveguide (4) and a right stepped waveguide (5), wherein the left stepped waveguide (4) and the right stepped waveguide (5) are respectively connected to two sides of the W-shaped groove waveguide (3); w type slot waveguide (3) comprise silica, left side notch cuttype waveguide (4) with right side notch cuttype waveguide (5) comprise by material silicon.

2. The W-type silicon slot on-chip polarization rotator based on the mode mixing principle as claimed in claim 1, wherein the strip waveguide (2) is wrapped outside the left-side stepped waveguide (4) and the right-side stepped waveguide (5) by taking air as a medium.

3. A W-type silicon trench on-chip polarization rotator based on mode mixing principle according to claim 2 characterized in that the W-type trench waveguide (3) comprises: a first waveguide (6), a second waveguide (7), a third waveguide (8) and a fourth waveguide (9); the first waveguides (6) are vertically distributed along the Y axis, and the second waveguides (7) are connected with the bottoms of the first waveguides (6) and are vertical to the first waveguides (6); the third waveguide (8) is connected with one end of the second waveguide (7) far away from the first waveguide (6) and is vertical to the second waveguide (7); the fourth waveguide (9) is connected with one end of the third waveguide (8) far away from the second waveguide (7) and is perpendicular to the third waveguide (8).

4. The W-shaped silicon groove type on-chip polarization rotator based on the mode mixing principle as claimed in claim 3Characterized in that the substrate (1) consists of silicon dioxide having a refractive index n at a wavelength of 1550nm_SiO2＝1.445。

5. The W-type silicon trench on-chip polarization rotator based on mode mixing principle as claimed in claim 4, wherein the W-type trench waveguide (3) is composed of silica having refractive index n at 1550nm wavelength_SiO21.445; the left-side stepped waveguide (4) and the right-side stepped waveguide (5) are both made of silicon, and the refractive index of silicon at 1550nm wavelength is n_Si＝3.455。

6. A W-type silicon slot on-chip polarization rotator based on mode mixing principle according to claim 5 characterized in that the thickness of the substrate (1) is 2 μm.

7. The W-type silicon-groove-type on-chip polarization rotator based on the mode mixing principle as claimed in claim 6, wherein the thickness H of the strip waveguide (2) is 400nm, the width W is 400nm, and the length along the transmission direction is L_C＝4.3um。

8. The W-type silicon slot on-chip polarization rotator based on the mode mixing principle as claimed in claim 7, wherein the width of the top of the left-side stepped waveguide (4) is W₁135 nm; the width of the connecting position of the left stepped waveguide (4) and the second waveguide (7) is W₂120 nm; the width and height of the connecting position of the left stepped waveguide (4) and the third waveguide (8) are H₂105 nm; the height of the left stepped waveguide (4) at one side of the fourth waveguide (9) is H₃＝150nm。

9. The W-type silicon slot type on-chip polarization rotator based on the mode mixing principle as claimed in claim 8, wherein the height of the contact position of the right-side stepped waveguide (5) and the first waveguide (6) is H₁100 nm; the width W of the contact position of the right stepped waveguide (5) and the fourth waveguide (9)₃＝100nm。

10. The W-type silicon-based slot-on-chip polarization rotator based on the mode mixing principle of claim 9, wherein the width of the first waveguide (6) is g₁-40 nm, said fourth waveguide (9) having a width g₂＝25nm。

Technical Field

The invention relates to the technical field of optical fiber communication, in particular to a W-type silicon-based groove type on-chip polarization rotator based on a mode mixing principle.

Background

Silicon photonic devices compatible with CMOS (complementary metal-oxide-semiconductor) processes have received widespread attention over the past decades, with SOI (Silicon-on-insulator) platform based photonic integrated waveguides (PICs) taking the leading position in the scientific research field. The high refractive index difference and the sub-micron structure of the SOI material result in SOI-based PIC devices with very high birefringence, which causes polarization dependent loss and polarization mode dispersion, limiting the application of SOI devices in the optical communication direction. The most effective solution to this problem is to introduce a polarization diversity system to reduce the polarization sensitivity of the silicon-based photonic device, so that the silicon-based photonic device has better performance for any polarized light, and the polarization diversity system generally consists of a Polarization Rotator (PR) and a Polarization Beam Splitter (PBS).

The current principles for implementing a Polarization Rotator (PR) can be classified into three types, a mode evolution type, a mode coupling type, and a mode mixing type.

The mode evolution type Polarization Rotator (PR) mainly realizes the gradual rotation of a polarization plane through the gradual change of a waveguide structure, and because a part of sharp edges can appear in the structure, the difference between the final performance parameters and the simulation result is large due to the fact that large deviation often appears in the actual process due to etching precision and the like, and meanwhile, the size of a mode evolution device is often large and difficult to integrate. Mode coupling type Polarization Rotators (PR) are usually realized by directional couplers, when effective refractive indexes of a TE mode in one waveguide and a TM mode in the other waveguide are the same, phase matching conditions are met, modes between the waveguides are coupled, and rotation is realized.

A mode hybrid type Polarization Rotator (PR) changes a transmission mode in a waveguide from a single mode to a hybrid mode by breaking cross-sectional symmetry, so that when TE mode or TM mode light is incident, energy is oscillated in two fundamental modes in the asymmetric cross-sectional waveguide, and polarization rotation is achieved by interference between the modes. Therefore, the key point for realizing the principle is to design the waveguide with the asymmetric section, and most of the existing schemes for realizing the asymmetric section realize the asymmetry of the section by mixing the silicon material and other materials so as to achieve the purpose of polarization rotation. However, due to the limitation of the manufacturing process, the manufacturing difficulty of most of waveguides with asymmetric cross sections is high, the tolerance is low, the manufacturing cost is increased, and the actual effect is not ideal.

Disclosure of Invention

In order to solve the problems of the prior art, the invention provides a W-type silicon groove type on-chip polarization rotator based on a mode mixing principle. The polarization rotator includes: the substrate consists of silicon dioxide, a section of strip waveguide is arranged at the top of the substrate to form a polarization rotation region; the strip waveguide includes: the waveguide comprises a W-shaped groove waveguide, a left stepped waveguide and a right stepped waveguide, wherein the left stepped waveguide and the right stepped waveguide are respectively connected to two sides of the W-shaped groove waveguide; the W-shaped groove waveguide is composed of silicon dioxide, and the left-side stepped waveguide and the right-side stepped waveguide are both composed of silicon.

And further, air is used as a medium to wrap the strip waveguide outside the left side stepped waveguide and the right side stepped waveguide.

Further, the W-type trench waveguide includes: a first waveguide, a second waveguide, a third waveguide, and a fourth waveguide; the first waveguides are vertically distributed along the Y axis, and the second waveguides are connected with the bottoms of the first waveguides and are vertical to the first waveguides; the third waveguide is connected with one end, far away from the first waveguide, of the second waveguide and is perpendicular to the second waveguide; the fourth waveguide is connected with one end, far away from the second waveguide, of the third waveguide, and is perpendicular to the third waveguide.

Further, the substrate is composed of silicon dioxide having a refractive index n at a wavelength of 1550nm_SiO2＝1.445。

Further, the W-type trench waveguide is composed of silica having a refractive index n at a wavelength of 1550nm_SiO21.445; the left-side stepped waveguide and the right-side stepped waveguide are both made of silicon, and the refractive index of silicon at 1550nm wavelength is n_Si＝3.455。

Further, the thickness of the substrate was 2 μm.

Further, the thickness H of the strip waveguide is 400nm, the width W of the strip waveguide is 400nm, and the length of the strip waveguide along the transmission direction is L_C＝4.3um。

Further, the width of the top of the left stepped waveguide is W₁135 nm; the width of the connecting position of the left stepped waveguide and the second waveguide is W₂120 nm; the width and height of the connection position of the left stepped waveguide and the third waveguide are H₂105 nm; the height of the left stepped waveguide at one side of the fourth waveguide is H₃＝150nm。

Further, the height of the position where the right stepped waveguide is in contact with the first waveguide is H₁100 nm; the width W of the contact position of the right stepped waveguide and the fourth waveguide₃＝100nm。

Further, the first waveguide has a width g₁The fourth waveguide has a width g of 40nm₂＝25nm。

The technical scheme provided by the embodiment of the invention has the following beneficial effects: in the invention, based on a standard SOI wafer structure, a substrate is a silicon dioxide waveguide, and a section of strip waveguide consisting of a W-shaped groove waveguide made of silicon dioxide and a left-side stepped waveguide and a right-side stepped waveguide made of silicon material is arranged above the silicon dioxide waveguide; the structure forms the W-type silicon-based groove type on-chip polarization rotator, so that the insertion loss IL of incident light (TE/TM fundamental mode) in the full-wave-band range is less than 0.4dB in the wavelength range of 300nm (1400nm-1700nm), mode light is input from an input port and output from an output port, meanwhile, the polarization rotation efficiency PCE is higher than 98.6% in the full-wave-band range, IL of the 1550nm central wavelength is less than 0.23dB, and the PCE is higher than 99.96%. In addition, tolerance analysis shows that when the parameters of the coupling region of the polarization rotator deviate from +/-10 nm, the polarization rotator keeps higher polarization rotation efficiency (PCE is more than 98%) and lower insertion loss (IL is less than 0.43dB) in a 300nm bandwidth, the manufacturing tolerance is large, the polarization rotator is simple in structure and high in process feasibility, and the polarization rotator has potential application value in the field of on-chip photonic integration.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a W-type silicon-based groove type on-chip polarization rotator based on a mode mixing principle provided by the invention;

FIG. 2 is a cross-sectional view of a W-type silicon slot on-chip polarization rotator provided by the present invention based on the principle of mode mixing;

FIG. 3 is a schematic structural diagram of a W-shaped trench waveguide provided in the present invention;

FIG. 4 is a TE diagram with two lowest-order mixed modes separately provided by the present invention₀And TM₀A mode field profile in cross section;

FIG. 5 is a separate input TE provided by the present invention₀And TM₀A polarization rotation process in mode;

FIG. 6 is a graph showing the calculation of light propagation characteristics in a waveguide for an input TE using a mode Expansion Method (EME) according to the present invention₀Mode conversion to output terminal TM₀Mode case, calculated polarization conversion efficiency and insertion loss as a function of coupling length L_CAnd a graph of the variation of the wavelength λ of the incident light;

in FIG. 7, (a) and (b) are respectively when TE is inputted₀In mode E_xAnd E_yThe transmission distribution diagram of the optical electric field component of (c) and (d) are respectively the current input TM₀In mode E_yAnd E_xThe transmission profile of the optical electric field component.

In FIG. 8, (a) and (b) are input TEs, respectively₀Mode and TM₀The insertion loss of the polarization rotator in mode is plotted against the polarization conversion efficiency.

In FIG. 9, (a) - (d) are for Δ W₁Respectively inputting TE in tolerance analysis of +/-10 nm₀And TM₀The transmittance curves of (e) - (h) are for Δ W₁Respectively inputting TE in tolerance analysis of +/-10 nm₀And TM₀Graph of insertion loss versus polarization rotation efficiency.

In FIG. 10, (a) - (d) are for Δ H₃Respectively inputting TE in tolerance analysis of +/-10 nm₀And TM₀The graph of transmittance when (e) - (H) are for Δ H₃Respectively inputting TE in tolerance analysis of +/-10 nm₀And TM₀Graph of insertion loss versus polarization rotation efficiency.

In FIG. 11, (a) - (d) are for Δ W₂Respectively inputting TE in tolerance analysis of +/-8 nm₀And TM₀The transmittance curves of (e) - (h) are for Δ W₂Respectively inputting TE in tolerance analysis of +/-8 nm₀And TM₀Graph of insertion loss versus polarization rotation efficiency.

In FIG. 12, (a) - (d) are for Δ H₂Respectively inputting TE in tolerance analysis of +/-8 nm₀And TM₀The graph of transmittance when (e) - (H) are for Δ H₂Respectively inputting TE in tolerance analysis of +/-8 nm₀And TM₀Graph of insertion loss versus polarization rotation efficiency.

Reference numerals: 1-a substrate; 2-a strip waveguide; 3-W type trench waveguide; 4-left side stepped waveguide; 5-right stepped waveguide; 6-a first waveguide; 7-a second waveguide; 8-a third waveguide; 9-fourth waveguide.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "upper", "lower", "left", "right" and the like as used herein are for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

FIG. 1 is a schematic structural diagram of a W-type silicon-based groove type on-chip polarization rotator based on a mode mixing principle provided by the invention; FIG. 2 is a cross-sectional view of a W-type silicon-based slot-on-chip polarization rotator provided by the invention based on the mode mixing principle. Referring to fig. 1-2, the polarization rotator includes: the polarization rotation device comprises a substrate 1, wherein the substrate 1 is composed of silicon dioxide, and a section of strip waveguide 2 is arranged at the top of the substrate 1 to form a polarization rotation region; the strip waveguide 2 includes: the W-shaped groove waveguide 3, the left stepped waveguide 4 and the right stepped waveguide 5 are respectively connected to two sides of the W-shaped groove waveguide 3; the W-shaped groove waveguide 3 is made of silicon dioxide, and the left stepped waveguide 4 and the right stepped waveguide 5 are made of silicon.

It should be noted that, the polarization rotator is focused on realizing the interconversion between different modes, and it can rotate the polarization direction of the light beam by 90 °, and convert one polarization state into another polarization state perpendicular to the polarization state while realizing the retention of the information carried by the polarization signal. Therefore, the polarization rotator has wide application in photonic integrated circuits, polarization division multiplexing coherent optical communication and quantum communication. With the rapid development of the information society, the structure of the polarization rotator is complicated based on a general cascade structure under the principle of the mode evolution type polarization rotator, and the manufacturing cost is increased. Therefore, the invention provides the W-type silicon-based groove type on-chip polarization rotator based on the mode mixing principle, which can not only input the optical signal TE₀Conversion to TM₀Mode out, and TM can also be output₀Mode conversion to TE₀An efficient scheme for mode output. When TE₀/TM₀When the mode is injected, due to the asymmetric structure of the waveguide, two mixed-mode lights are generated at the end face of the input light, and the TM is output by gradually rotating along with the transmission length₀/TE₀Mode(s).

In addition, FIG. 4 is a drawing of a display device provided by the present inventionTE for two lowest order mixed modes₀And TM₀A mode field profile in cross section; wherein TE₀Mode confinement in a predominantly W-type trench waveguide, TM₀The modes are mainly distributed in the left stepped waveguide 4, and the two modes respectively account for 50%. When TE is used, as shown in FIG. 4(a)₀When light in a polarization state is input, the two modes are excited almost equally, and because the two modes have different transmission constants in the asymmetric waveguide, 90-degree polarization rotation can be realized after the light is transmitted for a certain length L pi, so that TE (transverse electric) is enabled₀Mode conversion to TM₀Mode(s). TM₀Mechanism at input and TE₀Similarly.

FIG. 5 is a separate input TE provided by the present invention₀And TM₀Polarization rotation process at mode. Wherein S₁And S₂Two hybrid modes present in the structure, respectively. Input TE due to asymmetry of the cross-section₀Or TM₀In the mode, a mixed optical mode is generated in the optical waveguide. The two mixed mode polarization states S are generated by reasonably designing the size of the cross section₁、S₂At 45 deg. to the x-axis and y-axis, respectively, i.e. the transverse electric field component and the transverse magnetic field component in each mixed mode are identical, so that the TE is₀Mode and TM₀The modes are fully mixed, so that the polarization rotation function can be realized.

Further, the strip waveguide 2 is wrapped outside the left-side stepped waveguide 4 and the right-side stepped waveguide 5 by taking air as a medium. In order to increase the refractive index asymmetry in the perpendicular direction of the polarization rotator, air is used as a cladding, i.e., nAir ═ 1.

Further, referring to fig. 3, the W-type trench waveguide 3 includes: a first waveguide 6, a second waveguide 7, a third waveguide 8 and a fourth waveguide 9; the first waveguides 6 are vertically distributed along the Y axis, and the second waveguides 7 are connected with the bottom of the first waveguides 6 and are vertical to the first waveguides 6; the third waveguide 8 is connected with one end of the second waveguide 7 far away from the first waveguide 6 and is vertical to the second waveguide 7; the fourth waveguide 9 is connected to one end of the third waveguide 8 away from the second waveguide 7, and is perpendicular to the third waveguide 8.

Further, the substrate 1 is composed of silicon dioxide, which is at 155Refractive index of silica at 0nm wavelength of nSiO₂＝1.445。

Further, the W-type trench waveguide 3 is composed of silicon dioxide having a refractive index n at a wavelength of 1550nm_SiO21.445; the left-side stepped waveguide 4 and the right-side stepped waveguide 5 are both made of silicon, and the refractive index of the silicon at 1550nm wavelength is n_Si＝3.455。

Further, the thickness of the substrate 1 was 2 μm.

Further, the slab waveguide 2 has a thickness H of 400nm, a width W of 400nm, and a length L in the transmission direction_C＝4.3um。

Further, the width of the top of the left stepped waveguide 4 is W₁135 nm; the width of the connecting position of the left stepped waveguide 4 and the second waveguide 7 is W₂120 nm; the width and height of the connecting position of the left stepped waveguide 4 and the third waveguide 8 are H₂105 nm; the height of the left stepped waveguide 4 at one side of the fourth waveguide 9 is H₃＝150nm。

Further, the height of the position where the right stepped waveguide 5 contacts the first waveguide 6 is H₁100 nm; width W of contact position between right stepped waveguide 5 and fourth waveguide 9₃＝100nm。

Further, the first waveguide 6 has a width g₁40nm, the width of the fourth waveguide 9 is g₂＝25nm。

Fig. 6 is a diagram for calculating the light propagation characteristics in the waveguide using the mode Expansion Method (EME) and applying the calculated light propagation characteristics to the input TE₀Mode conversion to output terminal TM₀In the case of the mode, the dependent coupling length L is calculated_cAnd polarization conversion efficiency with a change in wavelength λ of incident light. FIG. 4(a) shows the analysis of insertion loss with the length L of the rotation region under these conditions_CAnd the wavelength λ of the incident light, from which it can be seen that L is the function of_CThe working wavelength band of the polarization rotator is increased from short wavelength to long wavelength, in order to increase the input TE between 1400nm and 1700nm as much as possible₀The conversion efficiency of the mode, Lc, is selected to be 4.3 μm. Similarly, FIG. 4(b) shows the analysis of polarization under this conditionConversion efficiency along with length L of rotating area_CAnd a change in wavelength λ of the incident light. It shows that the length of the rotation region of the polarization rotator is less affected by 4.3um ± 100nm on the conversion efficiency, and more affected by the performance after exceeding, so the length Lc of the rotation region of the polarization rotator is selected to be 4.3 μm, thereby obtaining all the structural parameters defining the polarization rotator: h ═ W ═ 400nm, W₁＝135nm，W₂＝120nm，W₃＝100nm，H₁＝100nm，H₂＝105nm，H₃＝150nm，g₁＝40nm，g₂25nm, polarization rotation length L_C4.3 μm. Under the parameter settings, the polarization rotator can realize the simultaneous realization of input polarized light TE in a wider (300nm) working wave band₀Conversion to TM₀And inputting polarized light TM₀Conversion to TE₀And (6) outputting the mode. The insertion loss is low in the bandwidth of 300nm, and the polarization conversion efficiency is excellent. Tolerance analysis shows that the polarization rotator still has high working performance in the E-to-U wave band of current optical fiber communication.

In FIG. 7, (a) and (b) are respectively when TE is inputted₀In mode E_xAnd E_yThe transmission profile of the photoelectric field component, from which the photoelectric field component E can be seen_xGradually decreases to disappear with the increase of the transmission distance in the rotation region, and the photoelectric field component E_yGradually increasing to the strongest. (c) And (d) are respectively as input TM₀In mode E_yAnd E_xThe transmission profile of the photoelectric field component, from which the photoelectric field component E can be seen_yGradually decreases to disappear with the increase of the transmission distance in the rotation region, and the photoelectric field component E_xGradually increasing to the strongest. It can be derived from FIG. 7 that TE is input regardless of the input₀Mode is also TM₀In a mode, the polarization rotator maintains better polarization rotation, and the good reciprocity of the polarization rotator is proved. The output end light field intensity also demonstrates the previously high polarization conversion efficiency.

In FIG. 8, (a) and (b) are input TEs, respectively₀Mode and TM₀The insertion loss and polarization conversion efficiency of the polarization rotator in mode. Can be seen to beTheory input TE₀Or TM₀The conversion efficiency of the polarization rotator is always higher than 98.6% in the wavelength range of 1400nm-1700nm, the insertion loss is higher than 99.96% at the position of 1550nm of the central wavelength, the insertion loss is lower than 0.4dB, and the insertion loss at the position of 1550nm of the central wavelength is only 0.23 dB.

The modern DUV photoetching process can generally achieve the purposes that the flatness of the line width on a chip is superior to 0.6nm, the flatness of the line width on the chip is superior to 2.6nm, and the nonuniformity in a 200mm SOI wafer is less than 1%, so that the maximum value of the tolerance in the width direction is 1% of the width, and the maximum value of the tolerance in the height direction is 10 nm.

In FIG. 9, (a) and (b) are W₁Manufacturing tolerance aw of₁When the input voltage is + -10nm, TE is input₀Mode time output TE₀And TM₀Transmittance in the mode, (c) and (d) are Δ W₁When the input is + -10nm, TM is input₀Mode time output TE₀And TM₀Transmittance of the mode. From (a) and (b), it can be seen that when Δ W₁Input TE of + -10nm₀Mode, output TE in the wavelength range of 1400nm-1700nm₀The transmittance of the mode is less than-15 dB; when inputting TM₀Mode, output terminal TM₀The mode transmittance is less than-15 dB. (e) And (g) is Δ W₁Respectively inputting TE when the input voltage is +10nm₀And TM₀Polarization Conversion Efficiency (PCE) and Insertion Loss (IL), (f) and (h) of the mode are Δ W₁Respectively inputting TE when the input voltage is-10 nm₀And TM₀Polarization Conversion Efficiency (PCE) and Insertion Loss (IL) of the mode. It can be seen that Δ W₁At +10nm, the PCE of the two modes in the wavelength range of 1400-1700nm is > 98.5%, IL is < 0.45dB, and Δ W₁PCE > 97.8% at 1400-1700nm wavelength range and IL <0.4 dB.

In FIG. 10, (a) and (b) are H₃Manufacturing tolerance Δ H of₃When the input voltage is +/-8 nm, inputting TE₀Mode time output TE₀And TM₀The transmittance in the mode (c) and (d) are Δ H₃When the input is +/-8 nm, inputting TM₀Mode time output TE₀And TM₀Transmittance of the mode. It can be seen from (a) and (b) that when Δ H₃Input TE ═ 8nm₀Mode in the wavelength range of 1400nm-1700nmInternal output terminal TE₀The transmittance of the mode is less than-15 dB; when inputting TM₀Mode output terminal TM₀The mode transmittance is less than-15 dB. (e) And (g) is Δ H₃Respectively inputting TE when the input voltage is +8nm₀And TM₀Polarization Conversion Efficiency (PCE) and Insertion Loss (IL), (f) and (H) of the modes are Δ H₃Respectively inputting TE when the input voltage is 8nm₀And TM₀Polarization Conversion Efficiency (PCE) and Insertion Loss (IL) of the mode. It can be seen that Δ H₃When +8nm, TE₀PCE > 97%, IL < 0.45dB, TM in the wavelength range of 1400-1700nm₀The PCE of the mode is more than 96.5 percent, IL is less than 0.45dB, and delta H₃The PCE of the two modes in the wavelength range of 1400nm-1700nm is more than 98.5% and the IL is less than 0.42dB when the wavelength is-8 nm.

In FIG. 11, (a) and (b) are W₂Manufacturing tolerance aw of₂When the input voltage is +/-8 nm, inputting TE₀Mode time output TE₀And TM₀Transmittance in the mode, (c) and (d) are Δ W₂When the input is +/-8 nm, inputting TM₀Mode time output TE₀And TM₀Transmittance of the mode. From (a) and (b), it can be seen that when Δ W₂Input TE ═ 8nm₀Mode, 0TE at output end in wavelength range of 1400nm-1700nm₀The transmittance of the mode is less than-15 dB; when inputting TM₀Mode output terminal TM₀The mode transmittance is less than-15 dB. (e) And (g) is Δ W₂Respectively inputting TE when the input voltage is +8nm₀And TM₀Polarization Conversion Efficiency (PCE) and Insertion Loss (IL), (f) and (h) of the mode are Δ W₂Respectively inputting TE when the input voltage is 8nm₀And TM₀Polarization Conversion Efficiency (PCE) and Insertion Loss (IL) of the mode. It can be seen that Δ W₂When +8nm, TE₀PCE > 97.5%, IL < 0.42dB, TM in the wavelength range of 1400nm-1700nm₀The PCE of the mode is more than 96.5 percent, IL is less than 0.45dB, and delta W₂PCE > 98.6% for both modes at-8 nm, IL <0.4 dB.

In FIG. 12, (a) and (b) are H₂Manufacturing tolerance Δ H of₂When the input voltage is +/-8 nm, inputting TE₀Mode time output TE₀And TM₀The transmittance in the mode (c) and (d) are Δ H₂When it is +/-8 nm, the blood is infusedInto TM₀Mode time output TE₀And TM₀Transmittance of the mode. It can be seen from (a) and (b) that when Δ H₂Input TE ═ 8nm₀Mode, 0TE at output end in wavelength range of 1400nm-1700nm₀The transmittance of the mode is less than-15 dB; when inputting TM₀Mode output terminal TM₀The mode transmittance is less than-15 dB. (e) And (g) is Δ H₂Respectively inputting TE when the input voltage is +8nm₀And TM₀Polarization Conversion Efficiency (PCE) and Insertion Loss (IL), (f) and (H) of the modes are Δ H₂Respectively inputting TE when the input voltage is 8nm₀And TM₀Polarization Conversion Efficiency (PCE) and Insertion Loss (IL) of the mode. It can be seen that Δ W₂When the wavelength is +8nm, the PCE of the two modes in the wavelength range of 1400nm-1700nm is more than 97.3 percent, and the IL is less than 0.42 dB; Δ H₂TE at-8 nm₀PCE > 98.5% for mode, IL <0.4dB, PCE > 97.6% for TM0 mode, IL < 0.42 dB.

It is worth pointing out that, in the invention, based on the standard SOI wafer structure, the substrate is a silicon dioxide waveguide, and a section of strip waveguide composed of a W-shaped groove waveguide made of silicon dioxide and a left-side stepped waveguide and a right-side stepped waveguide made of silicon material is arranged above the silicon dioxide waveguide; the structure forms the W-type silicon-based groove type on-chip polarization rotator, so that the insertion loss IL of incident light (TE/TM fundamental mode) in the full-wave-band range is less than 0.4dB in the wavelength range of 300nm (1400nm-1700nm), mode light is input from an input port and output from an output port, meanwhile, the polarization rotation efficiency PCE is higher than 98.6% in the full-wave-band range, IL of the 1550nm central wavelength is less than 0.23dB, and the PCE is higher than 99.96%. In addition, when the structural parameters of the coupling region of the polarization rotator deviate from +/-10 nm, the polarization rotator keeps higher polarization conversion efficiency and lower insertion loss PCE > 98.6% (IL <0.4dB) in a wider wave band (1400nm-1700nm), and has simple structure and high process feasibility.

The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.