Electro-optical modulator, photonic integrated chip and optical module

Abstract

The utility model discloses an electro-optical modulator, a photonic integrated chip and an optical module. The electro-optical modulator comprises a pair of modulation arms, and each modulation arm comprises a ridge-shaped part and a flat plate part connected with the two transverse sides of the ridge-shaped part; the modulation arm is provided with a P-type region and an N-type region which are transversely arranged side by side, and a longitudinal PN junction formed in the ridge part; the height of the flat plate part is within 1 / 3 of the height of the ridge-shaped part; and the transverse width of the ridge-shaped part is 0.8-1.5 times of the height of the ridge-shaped part. Compared with a conventional ridge-shaped part with a flat structure, the electro-optical modulator can enable an optical signal to work in a vertical polarized light (TM) mode in the electro-optical modulator by increasing the etching depth of the flat plate part, thereby enabling the direction of a light field to be consistent with the direction of a PN junction, enabling the overlap ratio of the light field and a PN junction depletion region to be good, and enabling the performance of the electro-optical modulator to be improved. And the modulation efficiency of the electro-optical modulator is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of optical communication element manufacturing, and specifically relates to an electro-optic modulator, a photon integrated chip and an optical module. Background Art

[0002] Silicon photonic chips can effectively reduce the cost and power consumption of modules in optical communication systems and are a key technology for achieving optical interconnection. Electro-optical modulators are one of the most important active devices in silicon photonic chips and play an extremely important role in high-speed optical communications. Their function is to convert high-speed changing electrical signals into high-speed changing optical signals.

[0003] The phase shift region of a typical electro-optic modulator is a ridge waveguide structure, specifically including a ridge portion and a flat portion. The ridge portion is usually a horizontal flat structure and adapts to horizontally polarized light (TE), while the PN junction of the ridge portion is distributed vertically. As a result, in the phase shift region of the electro-optic modulator, due to the inconsistency in the directions of the longitudinal PN junction and the transverse light field, the overlap between the light field and the PN junction depletion region is poor, which in turn limits the modulation efficiency of the electro-optic modulator and results in low modulation efficiency. Utility Model Content

[0004] In order to solve the problem of limited modulation efficiency, the utility model aims to provide an electro-optic modulator, a photonic integrated chip and an optical module.

[0005] To achieve the above object, an embodiment provides an electro-optic modulator. The electro-optic modulator includes a pair of modulation arms, each of which includes a ridge portion and a flat plate portion connected to two lateral sides of the ridge portion;

[0006] The modulation arm has a P-type region and an N-type region arranged side by side in a transverse direction, and a longitudinal PN junction formed in the ridge portion;

[0007] The height of the flat plate portion is within 1 / 3 of the height of the ridge portion; and the lateral width of the ridge portion is 0.8 to 1.5 times of its height.

[0008] As a further improvement of one embodiment, the lateral width of the ridge portion is 150 to 550 nm, and the height of the ridge portion is 250 to 400 nm.

[0009] As a further improvement of one embodiment, the lateral width of the flat plate portion is not less than 100 nm.

[0010] As a further improvement of an embodiment, the modulation arm further includes a step portion connected to a lateral end of the flat portion and away from the ridge portion, and a height of the step portion is greater than a height of the flat portion.

[0011] As a further improvement of one embodiment, the step portion is configured as a single-step structure or a multi-step structure, and the height of the step portion is within 2 / 3 of the height of the ridge-shaped portion.

[0012] As a further improvement of an embodiment, the modulation arm further comprises a contact portion connected to a lateral end of the step portion and facing away from the ridge portion;

[0013] The electro-optic modulator further includes two electrodes, one of the electrodes is electrically connected to one of the contact portions, and the other of the electrodes is electrically connected to the other of the contact portions.

[0014] As a further improvement of an embodiment, on either lateral side of the ridge portion, the height from the flat plate portion to the contact portion increases sequentially.

[0015] As a further improvement of an embodiment, the P-type region and the N-type region each have a lightly doped region, a medium doped region and a heavily doped region which are sequentially arranged in a lateral direction away from the PN junction;

[0016] The flat plate portion and the ridge portion intersect at the lightly doped region, the flat plate portion and the step portion intersect at the lightly doped region, the medium doped region or the heavily doped region, and the step portion and the contact portion intersect at the heavily doped region.

[0017] As a further improvement of an implementation manner, the P-type region and the N-type region are arranged to be mirror-symmetrical with respect to the PN junction.

[0018] As a further improvement of one embodiment, the electro-optic modulator further includes a beam splitter and a beam combiner, and a pair of the modulation arms are connected in parallel between the beam splitter and the beam combiner.

[0019] To achieve the above object, an embodiment provides a photonic integrated chip. The photonic integrated chip comprises a first polarization rotation unit and the electro-optical modulator arranged in sequence along an optical path;

[0020] The first polarization rotation unit is used to change the received horizontal polarized light into vertical polarized light;

[0021] The electro-optic modulator is used to receive the vertically polarized light and modulate the vertically polarized light.

[0022] As a further improvement of one embodiment, the photonic integrated chip further includes a second polarization rotation unit located at the output end of the electro-optic modulator, wherein the second polarization rotation unit is used to receive the modulated vertical polarized light and change the vertical polarized light into the horizontal polarized light.

[0023] As a further improvement of one embodiment, the photonic integrated chip further includes:

[0024] A total beam splitter is located in the incident light path of the first polarization rotation unit, or in the light path between the first polarization rotation unit and the electro-optical modulator.

[0025] To achieve the above object, an embodiment provides an optical module. The optical module includes a light emitting unit and the photon integrated chip.

[0026] The first polarization rotation unit is used to change the horizontal polarized light emitted by the light emitting unit into vertical polarized light, and the electro-optical modulator is used to receive the vertical polarized light and modulate the vertical polarized light.

[0027] Compared with the prior art, the beneficial effect of the utility model is at least that: compared with the ridge-shaped portion of the conventional flat structure, the electro-optic modulator of the present application can make the optical signal operate in the vertical polarized light (TM) mode in the electro-optic modulator by increasing the etching depth of the flat portion, that is, the electro-optic modulator can be suitable for modulating vertical polarized light, so that the direction of the light field is consistent with the direction of the PN junction, the light field and the PN junction depletion region have a good overlap, which is beneficial to improving the modulation efficiency of the electro-optic modulator. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of an electro-optic modulator according to Embodiment 1 of the present utility model;

[0029] Figure 2 It is a module schematic diagram of the optical path of the electro-optic modulator of Example 1 of the utility model;

[0030] Figure 3 is a schematic block diagram of the photon integrated chip of Embodiment 1 of the present utility model;

[0031] Figure 4 It is a structural schematic diagram of an electro-optic modulator according to Embodiment 2 of the present utility model;

[0032] Figure 5 is a schematic block diagram of a photon integrated chip according to Embodiment 3 of the present utility model;

[0033] Figure 6 It is a schematic block diagram of the photonic integrated chip of Example 4 of the utility model. DETAILED DESCRIPTION

[0034] The present invention will be described in detail below in conjunction with the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional changes made by a person skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0035] Example 1

[0036] See also Figure 1 and Figure 2 , this embodiment provides an electro-optical modulator 100, which is used to modulate a received optical signal and output a modulated optical signal.

[0037] Specifically, refer to Figure 1 The electro-optic modulator 100 includes a pair of modulation arms 10 , and each modulation arm 10 includes a P-type region 15 and an N-type region 16 .

[0038] The P-type region 15 and the N-type region 16 are arranged side by side in a first direction, and a PN junction 14 extending in a second direction is formed therebetween, wherein the first direction and the second direction are perpendicular to each other.

[0039] For ease of understanding and description, in this application, the first direction is defined as the horizontal direction and the second direction is defined as the vertical direction, that is, the horizontal direction is defined by the relative positions of the P-type region 15 and the N-type region 16 , and the vertical direction is defined by the protruding direction of the PN junction 14 .

[0040] When the electro-optic modulator 100 is working, by applying electrical signals to the P-type region 15 and the N-type region 16 respectively, a depletion region is generated at the PN junction 14, so that the effective refractive index of the optical signal propagating in the modulation arm 10 changes, thereby changing the phase of the optical signal and realizing modulation of the optical signal.

[0041] In terms of configuration, the modulation arm 10 includes a ridge portion 11 and flat plate portions 12 a and 12 b connected to two lateral sides of the ridge portion 11 .

[0042] Among them, the flat plate portion 12a is connected to one lateral side of the ridge-shaped portion 11, and the flat plate portion 12a and a part of the ridge-shaped portion 11 are formed in the P-type region 15; and the flat plate portion 12b is connected to the other lateral side of the ridge-shaped portion 11, and the flat plate portion 12b and the other part of the ridge-shaped portion 11 are formed in the N-type region 16.

[0043] The height of the flat plate portions 12a and 12b is smaller than that of the ridge portion 11, and the ridge portion 11 can be formed by etching. The ridge portion 11 protrudes longitudinally relative to the flat plate portions 12a and 12b.

[0044] The PN junction 14 is formed in the ridge portion 11 and its extending direction is substantially consistent with the protruding direction of the ridge portion 11 .

[0045] In the present application, the lateral width W of the ridge portion 11 is 0.8 to 1.5 times of its height H, that is, 0.8H≤W≤1.5H; and the height of the flat plate portions 12a and 12b is ≤H / 3.

[0046] Here, the “lateral width of the ridge-shaped portion 11” refers to the size of the ridge-shaped portion 11 in the second direction. For example, the ridge-shaped portion 11 has a side edge 111 protruding longitudinally from the flat plate portion 12a at one lateral end, and has a side edge 112 protruding longitudinally from the flat plate portion 12b at the other lateral end. The side edge 111 and the side edge 112 are substantially parallel and laterally opposite, and the spacing therebetween defines the lateral width of the ridge-shaped portion 11.

[0047] Similarly, in the present application, the "height of the ridge portion 11" refers to the size of the ridge portion 11 in the first direction, that is, the size of the P-type region 15 and the N-type region 16 constituting the ridge portion 11 in a direction parallel to the protruding direction of the ridge portion 11; similarly, the height of the flat portion 12a refers to the local size h of the P-type region 15 constituting the flat portion 12a in the first direction, and the height of the flat portion 12b refers to the local size h of the N-type region 16 constituting the flat portion 12b in the first direction.

[0048] Thus, compared to the conventional flat structure of the ridge portion 11, the present application can make the optical signal operate in the vertical polarized light (TM) mode in the electro-optic modulator 100 by increasing the etching depth of the flat plate portions 12a and 12b, that is, the electro-optic modulator 100 can be suitable for modulating vertical polarized light, so that the direction of the light field is consistent with the direction of the PN junction 14, and the light field and the PN junction depletion region have a good overlap, which is beneficial to improving the modulation efficiency of the electro-optic modulator 100.

[0049] It should be noted that the height of the flat plate portion 12a and the height of the flat plate portion 12b can be set to be the same, for example, as shown in the figure, they are marked with the same symbol h; and in the present application, the height of the flat plate portion 12a and the height of the flat plate portion 12b can also be set to be different.

[0050] The lateral width W of the ridge portion 11 is 150 to 550 nm, and the height H of the ridge portion 11 is 250 to 400 nm.

[0051] The lateral width w of the flat plate portion 12 a is not less than 100 nm. Similarly, the lateral width w of the flat plate portion 12 b is not less than 100 nm.

[0052] Here, the lateral width of the flat plate portion 12a and the lateral width of the flat plate portion 12b can be set to be the same, for example, as shown in the figure, they are marked with the same symbol w; and in the present application, the lateral width of the flat plate portion 12a and the lateral width of the flat plate portion 12b can also be set to be different.

[0053] Furthermore, the modulation arm 10 further includes contact portions 13a and 13b.

[0054] In this embodiment, the contact portion 13a is connected to the lateral end of the flat plate portion 12a and turns away from the ridge-shaped portion 11, that is, the contact portion 13a and the ridge-shaped portion 11 are separated at the two lateral ends of the flat plate portion 12a; the contact portion 13b is connected to the lateral end of the flat plate portion 12b and turns away from the ridge-shaped portion 11, that is, the contact portion 13b and the ridge-shaped portion 11 are separated at the two lateral ends of the flat plate portion 12b.

[0055] Each modulation arm 10 further includes electrodes 191 and 192 located around the modulation arm 10. The electrode 191 is electrically connected to the contact portion 13a, specifically through the conductive via structure 18; similarly, the electrode 192 is electrically connected to the contact portion 13b, specifically through the conductive via structure 18.

[0056] In this way, when the electro-optic modulator 100 is working, electrical signals are applied to the P-type region 15 and the N-type region 16 through the electrodes 191 and 192 respectively, so that the P-type region 15 is at a low potential and the N-type region 16 is at a high potential, and a depletion region is generated at the PN junction 14, so that the effective refractive index of the optical signal propagating in the modulation arm 10 changes, thereby changing the phase of the optical signal and realizing modulation of the optical signal.

[0057] Furthermore, on one lateral side of the ridge-shaped portion 11, the height from the flat plate portion 12a to the contact portion 13a increases successively, that is, the height of the contact portion 13a is greater than the height of the flat plate portion 12a; similarly, on the other lateral side of the ridge-shaped portion 11, the height from the flat plate portion 12b to the contact portion 13b increases successively, that is, the height of the contact portion 13b is greater than the height of the flat plate portion 12b.

[0058] In this embodiment, the height of the contact portions 13 a and 13 b is substantially consistent with the height H of the ridge portion 11 .

[0059] Furthermore, the P-type region 15 has a P-type lightly doped region 151, a medium doped region 152, and a heavily doped region 153 which are arranged in sequence in the lateral direction away from the PN junction 14. It can be understood that the P-type lightly doped region 151, the P-type medium doped region 152, and the P-type heavily doped region 153 are all P-type doped, and the doping concentration increases in sequence. Optionally, the doping concentration of the P-type lightly doped region 151 is 1×10 16 cm -3 ~1×10 18 cm -3 , the doping concentration of the P-type doping region 152 is 1×10 17 cm -3 ~1×10 20 cm -3 , the doping concentration of the P-type heavily doped region 153 is 1×10 19 cm -3 ~1×1022 cm -3 .

[0060] Similarly, the N-type region 16 has an N-type lightly doped region 161, an N-type medium doped region 162, and an N-type heavily doped region 163 which are arranged in sequence in the lateral direction away from the PN junction 14. It can be understood that the N-type lightly doped region 161, the N-type medium doped region 162, and the N-type heavily doped region 163 are all N-type doped, and the doping concentration increases in sequence. Optionally, the doping concentration of the N-type lightly doped region 161 is 1×10 16 cm -3 ~1×10 18 cm -3 , the doping concentration of the N-type doping region 162 is 1×10 17 cm -3 ~1×10 20 cm -3 , the doping concentration of the N-type heavily doped region 163 is 1×10 19 cm -3 ~1×10 22 cm -3 .

[0061] In this embodiment, the flat plate portion 12a and the ridge portion 11 intersect at the P-type lightly doped region 151, and the flat plate portion 12a and the contact portion 13a intersect at the P-type heavily doped region 153. That is, a portion of the P-type lightly doped region 151 is located at the ridge portion 11, and another portion is located at the flat plate portion 12a; a portion of the P-type heavily doped region 153 is located at the contact portion 13a, and another portion is located at the flat plate portion 12a; and the P-type medium doped region 152 is located at the flat plate portion 12a.

[0062] The plate portion 12b and the ridge portion 11 intersect at the N-type lightly doped region 161, and the plate portion 12b and the contact portion 13b intersect at the N-type heavily doped region 163. That is, a portion of the N-type lightly doped region 161 is located at the ridge portion 11, and another portion is located at the plate portion 12b; a portion of the N-type heavily doped region 163 is located at the contact portion 13b, and another portion is located at the plate portion 12b; and the N-type medium doped region 162 is located at the plate portion 12b.

[0063] That is, the P-type heavily doped region 153 of the P-type region 15 is electrically connected to the electrode 191 and is connected to a relatively low potential through the electrode 191 ; the N-type heavily doped region 163 of the N-type region 16 is electrically connected to the electrode 192 and is connected to a relatively high potential through the electrode 192 .

[0064] In this embodiment, the shape of the modulation arm 10 is set to be mirror-symmetrical with the PN junction 14 as the symmetry plane. Accordingly, in the ridge portion 11, the lateral width of the N-type lightly doped region 161 of the N-type region 16 is the same as the lateral width of the P-type lightly doped region 151 of the P-type region 15, and the height of the N-type lightly doped region 161 is the same as the height of the P-type lightly doped region 151; the plate portion 12a and the plate portion 12b have the same height and width; the contact portion 13a and the contact portion 13b have the same height and width.

[0065] In addition, the P-type lightly doped region 151 and the N-type lightly doped region 161 have different doping ion types, but the doping concentrations are basically the same (for example, of the same order of magnitude); similarly, the P-type medium doped region 152 and the N-type medium doped region 162 have different doping ion types, but the doping concentrations are basically the same (for example, of the same order of magnitude); similarly, the P-type heavily doped region 153 and the N-type heavily doped region 163 have different doping ion types, but the doping concentrations are basically the same (for example, of the same order of magnitude).

[0066] Further, see Figure 2 The electro-optic modulator 100 further includes a beam splitter 101 and a beam combiner 102. A pair of modulation arms 10 are arranged in parallel between the beam splitter 101 and the beam combiner 102.

[0067] In the application of the electro-optic modulator 100, the vertical polarized light received by the electro-optic modulator 100 is first split into two beams of vertical polarized light by the beam splitter 101, wherein one beam of vertical polarized light is output to one modulation arm 10 for modulation, and the other beam of vertical polarized light is output to the other modulation arm 10 for modulation, and the two modulated beams of vertical polarized light are both output to the beam combiner 102, and the beam combiner 102 combines the two beams of vertical polarized light into one beam of vertical polarized light, and then outputs it.

[0068] Specifically, the electro-optic modulator 100 may be a Mach–Zehnder Modulator (MZM for short).

[0069] Further, Figure 3 This embodiment also provides a photonic integrated chip, which includes the electro-optic modulator 100.

[0070] Specifically, the photonic integrated chip comprises a first polarization rotation unit 201 and an electro-optic modulator 100 which are sequentially arranged along the transmission direction of the optical path.

[0071] That is, the first polarization rotation unit 201 is relatively in front, and the electro-optical modulator 100 is relatively in the back. In the present application, "front" and "back" are defined based on the light transmission direction. "Front" means that the light signal in the light path arrives first, and "back" means that the light signal in the light path arrives later.

[0072] The first polarization rotation unit 201 is used to receive horizontally polarized light, and change the polarization state of the received horizontally polarized light, that is, convert it into vertically polarized light, and then output the vertically polarized light backward.

[0073] From the foregoing introduction, it can be seen that the photonic integrated chip of this embodiment, when receiving the vertically polarized light output by the first polarization rotation unit 201, its electro-optical modulator 100 has excellent adaptability to the vertically polarized light, the direction of the light field is consistent with the direction of the PN junction 14, the overlap between the light field and the PN junction depletion region is good, the modulation efficiency is greatly improved, and thus the coupling loss of the photonic integrated chip is reduced.

[0074] Furthermore, the photonic integrated chip further includes a second polarization rotation unit 202 located at the output end of the electro-optic modulator 100 .

[0075] The second polarization rotation unit 202 is used to receive the modulated vertical polarized light, and change the polarization state of the received vertical polarized light, that is, convert it into horizontal polarized light, and then output the horizontal polarized light backward.

[0076] Thus, by sequentially arranging the first polarization rotation unit 201, the electro-optic modulator 100 and the second polarization rotation unit 202 along the optical path, vertically polarized light is transmitted in the electro-optic modulator 100, thereby greatly reducing the nonlinear loss caused by light transmission on the ridge waveguide.

[0077] Furthermore, this embodiment also provides an optical module, which includes a housing, a circuit board, and the photonic integrated chip, and correspondingly, also includes the electro-optic modulator 100 .

[0078] The housing forms a housing cavity for accommodating at least the photonic integrated chip and the circuit board. The housing forms an optical port, which allows the optical module to be connected to an external optical fiber. The optical signal emitted by the optical component is output to the external optical fiber at the optical port to realize the optical signal transmission function of the optical module.

[0079] In addition, the optical module may further include a light emitting unit, a focusing lens, a first isolator, a mode spot conversion unit, a second isolator, a coupling lens, an optical fiber, and the like.

[0080] For example, the light emitting unit, the focusing lens, the first isolator, and the mode spot conversion unit are sequentially arranged in the optical path before the photonic integrated chip (in order of Figure 3 For example, that is, in the optical path before the first polarization rotation unit 201), the second isolator, the coupling lens, and the optical fiber are sequentially arranged in the optical path after the photonic integrated chip (with Figure 3 For example, that is, in the light path after the second polarization rotation unit 202).

[0081] When the photonic integrated chip is working, the light emitting unit emits horizontally polarized light, and the light signal passes through the focusing lens, the first isolator, and the mode spot conversion unit in sequence, and then enters the first polarization rotation unit 201; the first polarization rotation unit 201 converts the horizontal polarized light into vertical polarized light; then, the vertical polarized light enters the electro-optic modulator 100, and the beam splitter 101 splits the vertical polarized light into two paths, and modulates them respectively through the two modulation arms of the electro-optic modulator, and then the two modulated vertical polarized lights are combined into one vertical polarized light through the beam combiner 102 to serve as the output light of the electro-optic modulator 100; then, the output vertical polarized light is converted into horizontal polarized light by the second polarization rotation unit 202; then, the horizontal polarized light passes through the second isolator, the coupling lens, and the optical fiber in sequence to be emitted backward.

[0082] The light emitting unit may be configured as a semiconductor laser, specifically a distributed feedback laser (DFB-LD), and may of course also be implemented as other light emitters known in the art.

[0083] In one implementation, the optical module may be a TOSA (Total Optical Spectrum Sender) having only an optical transmission function, or an integrated optical transceiver having both an optical transmission function and an optical reception function.

[0084] In summary, this embodiment has at least the following beneficial effects: compared with the ridge portion 11 of the conventional flat structure, this embodiment increases the etching depth of the flat plate portions 12a and 12b, so that the optical signal can operate in the vertical polarized light (TM) mode in the electro-optic modulator 100, so that the direction of the light field is consistent with the direction of the PN junction 14, and the light field and the depletion region of the PN junction 14 have a good overlap, which is beneficial to improving the modulation efficiency of the electro-optic modulator 100.

[0085] Example 2

[0086] See also Figure 4 This embodiment provides an electro-optic modulator, as well as a photonic integrated chip and an optical module having the electro-optic modulator.

[0087] This embodiment is basically the same as the aforementioned embodiment 1, and the only difference is that an additional step portion 17a is added between the flat plate portion 12a and the contact portion 13a, and an additional step portion 17b is added between the flat plate portion 12b and the contact portion 13b. In addition, the rest of the contents of this embodiment are the same as those of embodiment 1, and only the above-mentioned differences are introduced below. For other identical technical contents, please refer to embodiment 1, which will not be repeated here.

[0088] Specifically, in the above embodiment 1, the lateral end of the flat plate portion 12a is connected to the contact portion 13a, and the lateral end of the flat plate portion 12b is connected to the contact portion 13b. However, unlike the above embodiment 1, in this embodiment, the modulation arm 10 further includes step portions 17a and 17b.

[0089] Specifically, the step portion 17a is connected to the lateral end of the flat portion 12a and is away from the ridge portion 11, that is, the step portion 17a and the ridge portion 11 are separated at the lateral ends of the flat portion 12a, and the height h1 of the step portion 17a is greater than the height h of the flat portion 12a.

[0090] Similarly, the step portion 17b is connected to the lateral end of the flat portion 12b and is away from the ridge portion 11, that is, the step portion 17b and the ridge portion 11 are separated at the lateral ends of the flat portion 12b, and the height h1 of the step portion 17b is greater than the height h of the flat portion 12b.

[0091] In this way, while ensuring that the flat plate portions 12a and 12b are obtained by deep etching, compared with Example 1, this embodiment provides step portions 17a and 17b with greater height at the end of the flat plate portions 12a and 12b that are away from the ridge-shaped portion 11, so that the flat plate portions 12a and 12b and the step portions 17a and 17b together constitute the connection areas on both sides of the ridge-shaped portion 11 (i.e., the channels for electrical connection), thereby utilizing the step portions 17a and 17b to greatly reduce the resistance of the modulation arm 10 and improve the bandwidth of the electro-optical modulator.

[0092] Here, similar to what is described in the previous embodiment 1, in the present application, the height of the step portion 17a refers to the local dimension h1 of the P-type region 15 constituting the step portion 17a in the first direction, and the height of the step portion 17b refers to the local dimension h1 of the N-type region 16 constituting the step portion 17b in the first direction.

[0093] The height of the step portion 17a and the height of the step portion 17b can be set to be the same, for example, as shown in the figure, they are marked with the same symbol h1; however, in the present application, the height of the step portion 17a and the height of the step portion 17b can also be set to be different.

[0094] Correspondingly, different from the above-mentioned embodiment 1, in this embodiment, the contact portion 13a of the modulation arm 10 is connected to the lateral end of the step portion 17a and is away from the ridge-shaped portion 11; the contact portion 13b of the modulation arm 10 is connected to the lateral end of the step portion 17b and is away from the ridge-shaped portion 11.

[0095] That is, in the above embodiment 1, the flat plate portions 12a, 12b are directly connected to the contact portions 13a, 13b respectively. In this embodiment, step portions 17a, 17b are added between the flat plate portions 12a, 12b and the contact portions 13a, 13b respectively.

[0096] Further, in the present embodiment, the step portion 17a is set as a single-step structure, that is, it has a single constant height h1; similarly, the step portion 17b is set as a single-step structure, that is, it has a single constant height h1. Preferably, the height h1 of the step portions 17a and 12b is ≤ 2H / 3. The step portions 17a and 17b of the present application are not limited to a single-step structure. For example, in a variation embodiment, the step portions 17a and 17b can also be set as a multi-step structure, for example, each including a first step with a single constant height h1 and a second or more steps with a height less than h1.

[0097] Preferably, on one lateral side of the ridge-shaped portion 11, the height from the flat plate portion 12a to the contact portion 13a increases in sequence, that is, the height of the contact portion 13a is greater than the height h1 of the step portion 17a, and the height h1 of the step portion 17a is greater than the height h of the flat plate portion 12a. When the step portion 17a is a multi-step structure, the height of each step also increases step by step as it approaches the contact portion 13a. Similarly, on the other lateral side of the ridge-shaped portion 11, the height from the flat plate portion 12b to the contact portion 13b increases in sequence, that is, the height of the contact portion 13b is greater than the height h1 of the step portion 17b, and the height h1 of the step portion 17b is greater than the height h of the flat plate portion 12b. When the step portion 17b is a multi-step structure, the height of each step also increases step by step as it approaches the contact portion 13b.

[0098] Further, in this embodiment, the flat plate portion 12a and the ridge portion 11 intersect at the P-type lightly doped region 151, the step portion 17a and the contact portion 13a intersect at the P-type heavily doped region 153, and the step portion 17a and the flat plate portion 12a can be as follows: Figure 3 As shown, it intersects with the P-type medium doping region 152 , or can be changed to intersect with the P-type lightly doped region 151 , or can be changed to intersect with the P-type heavily doped region 153 .

[0099] Similarly, the flat plate portion 12b and the ridge portion 11 intersect at the N-type lightly doped region 161, and the step portion 17b and the contact portion 13b intersect at the N-type heavily doped region 163. The step portion 17b and the flat plate portion 12b may be as follows: Figure 3 As shown, the intersection is at the N-type medium doping region 162 , or may be changed to intersect at the N-type lightly doped region 161 , or may be changed to intersect at the N-type heavily doped region 163 .

[0100] In this embodiment, the shape of the modulation arm 10 is set to be mirror-symmetric with the PN junction 14. Accordingly, in the ridge portion 11, the lateral width of the N-type lightly doped region 161 of the N-type region 16 is the same as the lateral width of the P-type lightly doped region 151 of the P-type region 15, and the height of the N-type lightly doped region 161 is the same as the height of the P-type lightly doped region 151; the plate portion 12a and the plate portion 12b have the same height and width; the step portion 17a and the step portion 17b have the same height and width; the contact portion 13a and the contact portion 13b have the same height and width.

[0101] Compared with the previous embodiment 1, this embodiment 2 has further beneficial effects: by providing step portions 17a and 17b with greater height at the end of the flat portion 12a and 12b away from the ridge portion 11, the flat portion 12a and 12b and the step portions 17a and 17b together constitute the connection areas on both sides of the ridge portion 11 (i.e., the channels for electrical connection), so that the step portions 17a and 17b can be used to greatly reduce the resistance of the modulation arm 10 and improve the bandwidth of the electro-optical modulator.

[0102] Example 3

[0103] Ginseng Figure 5 This embodiment provides an electro-optic modulator, as well as a photonic integrated chip and an optical module having the electro-optic modulator.

[0104] The electro-optic modulator of this embodiment can be completely the same as the electro-optic modulator described in the above-described embodiment 1 or embodiment 2, and the difference between this embodiment and the above-described embodiment 1 or embodiment 2 is that the photon integrated chip has more than two optical outputs and corresponding optical path structures. These differences are described below.

[0105] In this embodiment, the photonic integrated chip includes a total beam splitter 203, and the total beam splitter 203 is used to split the received optical signal into n optical signals.

[0106] Here, n is set to a positive integer greater than 2, such as 2, 3, 4, 8, 12, etc.

[0107] In this embodiment, corresponding to the n optical signals, the photonic integrated chip further includes a first polarization rotation unit 201, an electro-optical modulator 100, and a second polarization rotation unit 202 in each of the n optical signals. Thus, each optical signal output by the total beam splitter 203 is first converted into vertically polarized light by the first polarization rotation unit 201 in the optical path, then modulated by the electro-optical modulator 100 in the optical path, and then converted into horizontally polarized light by the second polarization rotation unit 202 in the optical path, and then continues to be output backward.

[0108] The optical module includes a light emitting unit, a focusing lens, a first isolator, and a mode spot conversion unit which are sequentially arranged in the incident light path of the total beam splitter 203. The light emitting unit emits horizontally polarized light. After passing through the focusing lens, the first isolator, and the mode spot conversion unit in sequence, the light signal enters the total beam splitter 203 and is divided into n light signals by the total beam splitter 203.

[0109] In addition, corresponding to the n optical signals, the optical module further includes a second isolator, a coupling lens, an optical fiber, etc. in each of the n optical signals. After the second polarization rotation unit 202 in each path converts the vertical polarized light into horizontal polarized light, the horizontal polarized light passes through the second isolator, coupling lens, and optical fiber in the optical path in sequence to be emitted backward. Thus, the photonic integrated chip realizes the output of n optical signals.

[0110] The other technical contents of this embodiment are the same as those of the previous embodiment 1 or embodiment 2 and will not be repeated here.

[0111] Example 4

[0112] Ginseng Figure 6 This embodiment provides an electro-optic modulator, as well as a photonic integrated chip and an optical module having the electro-optic modulator.

[0113] This embodiment is basically the same as the previously described embodiment 3, and the difference between this embodiment and the previously described embodiment 3 is only the position of the total beam splitter 203 in the optical path and the number of first polarization rotation units 201 adapted thereto. These differences are described below.

[0114] In the aforementioned embodiment 3, the total beam splitter 203 is located in the optical path before the n first polarization rotation units 201 . In other words, the n optical signals split by the total beam splitter 203 each have a corresponding first polarization rotation unit 201 .

[0115] In this embodiment, the total beam splitter 203 is located in the optical path after the first polarization rotation unit 201, that is, in the output optical path of the first polarization rotation unit 201. In this way, one path of horizontal polarized light is first converted into vertical polarized light by the first polarization rotation unit 201, and the total beam splitter 203 is used to receive the vertical polarized light from the first polarization rotation unit 201 and divide the vertical polarized light into n paths of vertical polarized light, and each path of vertical polarized light output by the total beam splitter 203 is output to the electro-optical modulator 100 in each optical path for modulation, and then converted into horizontal polarized light by the second polarization rotation unit 202 in each optical path, and then continuously output backward.

[0116] The other technical contents of this embodiment are the same as those of the previous embodiment 3 and will not be repeated here.

[0117] In summary, the beneficial effect of the present application is that compared with the ridge-shaped portion 11 of the conventional flat structure, the electro-optic modulator 100 of the present application can make the optical signal operate in the vertical polarized light (TM) mode in the electro-optic modulator 100 by increasing the etching depth of the flat plate portions 12a and 12b, that is, the electro-optic modulator can be suitable for modulating vertical polarized light, so that the direction of the light field is consistent with the direction of the PN junction 14, and the overlap between the light field and the PN junction depletion region is good, which is beneficial to improving the modulation efficiency of the electro-optic modulator 100.

[0118] It should be understood that although the present specification is described according to embodiments, not every embodiment contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0119] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the utility model. They are not intended to limit the protection scope of the utility model. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. An electro-optic modulator, comprising a pair of modulation arms, each of the modulation arms comprising a ridge portion and a flat plate portion connected to two lateral sides of the ridge portion; The modulation arm has a P-type region and an N-type region arranged side by side in a transverse direction, and a longitudinal PN junction formed in the ridge portion; characterized in that: The height of the flat plate portion is within 1 / 3 of the height of the ridge portion; and the lateral width of the ridge portion is 0.8 to 1.5 times of its height.

2. The electro-optic modulator according to claim 1, characterized in that The lateral width of the ridge portion is 150 to 550 nm, and the height of the ridge portion is 250 to 400 nm.

3. The electro-optic modulator according to claim 1, characterized in that The lateral width of the flat plate portion is not less than 100 nm.

4. The electro-optic modulator according to claim 1, characterized in that The modulation arm further includes a step portion connected to a lateral end of the flat plate portion and facing away from the ridge portion, wherein a height of the step portion is greater than a height of the flat plate portion.

5. The electro-optic modulator according to claim 4, characterized in that The step portion is configured as a single-step structure or a multi-step structure, and the height of the step portion is within 2 / 3 of the height of the ridge portion.

6. The electro-optic modulator according to claim 4, characterized in that The modulation arm further includes a contact portion connected to a lateral end of the step portion and facing away from the ridge portion; The electro-optic modulator further includes two electrodes, one of the electrodes is electrically connected to one of the contact portions, and the other of the electrodes is electrically connected to the other of the contact portions.

7. The electro-optic modulator according to claim 6, characterized in that On either lateral side of the ridge portion, the height from the flat plate portion to the contact portion increases sequentially.

8. The electro-optic modulator according to claim 6, characterized in that The P-type region and the N-type region each have a lightly doped region, a medium doped region and a heavily doped region which are sequentially arranged in a lateral direction away from the PN junction; The flat plate portion and the ridge portion intersect at the lightly doped region, the flat plate portion and the step portion intersect at the lightly doped region, the medium doped region or the heavily doped region, and the step portion and the contact portion intersect at the heavily doped region.

9. The electro-optic modulator according to claim 1, characterized in that: The P-type region and the N-type region are arranged to be mirror-symmetrical with respect to the PN junction.

10. The electro-optic modulator according to claim 1, characterized in that: The electro-optic modulator further includes a beam splitter and a beam combiner, and a pair of modulation arms are connected in parallel between the beam splitter and the beam combiner.

11. A photonic integrated chip, characterized in that: The photonic integrated chip comprises a first polarization rotation unit and an electro-optic modulator according to any one of claims 1 to 10 which are sequentially arranged along an optical path; The first polarization rotation unit is used to change the received horizontal polarized light into vertical polarized light; The electro-optic modulator is used to receive the vertically polarized light and modulate the vertically polarized light.

12. The photonic integrated chip according to claim 11, characterized in that: The photonic integrated chip further comprises a second polarization rotation unit located at the output end of the electro-optic modulator, wherein the second polarization rotation unit is used for receiving the modulated vertical polarized light and changing the vertical polarized light into the horizontal polarized light.

13. The photonic integrated chip according to claim 11, characterized in that: The photon integrated chip further comprises: A total beam splitter is located in the incident light path of the first polarization rotation unit, or in the light path between the first polarization rotation unit and the electro-optical modulator.

14. An optical module, characterized in that: The optical module comprises a light emitting unit and the photonic integrated chip according to any one of claims 11 to 13, The first polarization rotation unit is used to change the horizontal polarized light emitted by the light emitting unit into vertical polarized light, and the electro-optical modulator is used to receive the vertical polarized light and modulate the vertical polarized light.

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