CN112666728B - an electro-optic modulator - Google Patents

Abstract

The present application discloses an electro-optic modulator, comprising a ridge waveguide, the ridge waveguide includes a ridge portion and a flat plate portion; a first doped region and a second doped region are arranged in the ridge waveguide, and the first doped region and the second doped region are arranged in the ridge waveguide. The doping types of the two doped regions are different; wherein, the first doped region includes a vertical region and a horizontal region which are arranged in the ridge portion and extend along the extending direction of the ridge portion, and are spaced along the extending direction of the ridge portion A plurality of vertical regions are set; the second doped region includes the part of the ridge except the first doped region, and is adjacent to the horizontal region, the vertical region and the vertical region of the first doped region respectively to form , the vertical direction and the vertical direction of the PN junction. The application designs multiple PN junctions in different directions in the ridge waveguide, which expands the range of the depletion region, effectively improves the modulation efficiency, reduces the optical loss, and does not introduce additional parasitic capacitance to avoid the additional capacitance affecting the modulation bandwidth.

Description

an electro-optic modulator

technical field

The present application relates to the technical field of optical devices, in particular to an electro-optical modulator.

Background technique

Silicon-based electro-optic modulator is one of the most important active devices in silicon-based optoelectronic chips, and plays an extremely important role in high-speed optical communication. Its function is to convert a high-speed changing electrical signal into a high-speed changing optical signal.

In the silicon photonics chip with single-wavelength 25G and above application scenarios, the most feasible and commonly used technical solution is the carrier depletion modulator (Carrier Depletion Modulator) based on the plasma dispersion effect. (Phase shifter) is a ridge waveguide structure, as shown in Figure 1, including a ridge part 11' and a flat plate part (slab part) 12', and the P-type doping 13' and N-type doping formed in the ridge part 11' The dopant 14', the P-type doping 13' and the N-type doping 14' are adjacent to form a vertical PN junction extending along the extending direction of the ridge portion. In the modulator with this structure, the depletion layer of the PN junction is only at the adjacent place of the two P-type doping 13' and N-type doping 14', and the modulation efficiency of the optical signal propagating in the ridge waveguide is low, which is difficult to meet High-speed optical communication requires high modulation efficiency of high-speed optical modulators.

Contents of the invention

The purpose of the present application is to provide an electro-optic modulator with higher light modulation efficiency or lower light loss.

In order to achieve one of the above objects, the present application provides an electro-optic modulator, including a ridge waveguide, the ridge waveguide includes a ridge portion and flat plate portions located on both sides of the ridge portion;

A first doped region and a second doped region are provided in the ridge waveguide, and the doping type of the first doped region is opposite to that of the second doped region;

The first doped region includes a vertical region and a horizontal region arranged in the ridge portion and extending along the extending direction of the ridge portion, and a plurality of intervals arranged along the extending direction of the ridge portion a vertical area, the vertical area extends into the flat plate portion on one side of the ridge portion along a direction perpendicular to the extending direction of the ridge portion;

The horizontal area, the vertical area and the vertical area are connected together, the bottoms of the horizontal area and the vertical area are higher than the bottom of the ridge waveguide, and the width of the horizontal area is smaller than that of the ridge waveguide. the width of the section;

The second doped region includes a portion of the ridge portion except the first doped region, and the second doped region extends into a flat plate portion on the other side opposite to the vertical region;

The second doped region is adjacent to the horizontal region, the vertical region and the vertical region of the first doped region to form a PN junction including the horizontal direction, the vertical direction and the vertical direction, respectively.

As a further improvement of the embodiment, the horizontal region of the first doped region is located at the bottom, middle or top of the vertical region.

As a further improvement of the embodiment, the horizontal region of the first doped region is located on one side or both sides of the vertical region.

As a further improvement of the embodiment, the bottoms of the horizontal region and the vertical region of the first doped region are at least 50 nm higher than the bottom of the ridge waveguide.

As a further improvement of the embodiment, the thickness of the horizontal region of the first doped region is greater than or equal to 30 nm.

As a further improvement of the embodiment, the plurality of vertical regions are arranged at equal intervals along the extending direction of the ridge portion.

As a further improvement of the embodiment, the duty cycle of the vertical region is 20%-80%.

As a further improvement of the embodiment, the slab portion where the vertical region is located is an intrinsic region or a first lightly doped region; the doping type of the first lightly doped region is the same as that of the first doped region.

As a further improvement of the embodiment, the width of the horizontal area is greater than or equal to the width of the vertical area.

As a further improvement of the implementation, the ridge waveguide further includes a first heavily doped region and a second heavily doped region: the first heavily doped region is located outside the vertical region of the first doped region and is adjacent to the vertical The end of the region is connected, the doping type of the first heavily doped region is the same as that of the first doped region, and its doping concentration is higher than that of the first doped region; the second heavily doped region The doped region is located outside the second doped region and connected to the second doped region, the second heavily doped region has the same doping type as the second doped region, and its doping concentration is higher than The doping concentration of the second doped region; the electro-optic modulator further includes at least two electrodes, and the first heavily doped region and the second heavily doped region are respectively electrically connected to the two electrodes.

As a further improvement of the embodiment, the extension length of the vertical region into the flat plate portion is greater than or equal to 500 nm.

As a further improvement of the embodiment, the ridge waveguide further includes a first moderately doped region and a second moderately doped region: the first moderately doped region is located between the first doped region and the first heavily doped Between the doped regions, connected to the end of the vertical region, the doping type of the first middle doped region is the same as that of the first doped region, and its doping concentration is higher than that of the first doped region The doping concentration is lower than the doping concentration of the first heavily doped region; the second medium doped region is located between the second doped region and the second heavily doped region, and the first The doping type of the second doped region is the same as that of the second doped region, and its doping concentration is higher than that of the second doped region, but lower than that of the second heavily doped region. concentration.

As a further improvement of the embodiment, the extension length of the vertical region into the flat plate part is between 0 nm and 500 nm.

The present application also provides another electro-optic modulator, which includes a ridge waveguide, and the ridge waveguide includes a ridge portion and flat plate portions located on both sides of the ridge portion;

A first doped region and a second doped region are provided in the ridge waveguide, and the doping type of the first doped region is opposite to that of the second doped region;

The first doped region includes a middle doped region arranged in the ridge portion and extending along the extension direction of the ridge portion, and a plurality of vertical doped regions arranged at intervals along the extension direction of the ridge portion. impurity region, the vertical doped region extends into the flat plate on one side of the ridge along a direction perpendicular to the extending direction of the ridge; the vertical doped region is connected to the central doped region ;

The second doped region includes two side doped regions located in the ridge portion on both sides of the central doped region of the first doped region, and located above the first doped region. The top doped region and/or the bottom doped region below; the two side doped regions are connected by the top doped region and/or the bottom doped region; the second doped region extends to the In the plate part on the other side opposite to the vertical doping region;

The second doped region is adjacent to the first doped region to form a PN junction including a horizontal direction, a vertical direction and a vertical direction.

As a further improvement of the embodiment, the cross-section of the central doped region of the first doped region is rectangular; or the central doped region of the first doped region includes a vertical region and a horizontal region, and the vertical The zone is connected to the horizontal zone.

As a further improvement of the embodiment, the slab portion where the vertical region is located is an intrinsic region or a first lightly doped region; the doping type of the first lightly doped region is the same as that of the first doped region.

As a further improvement of the embodiment, the width of the side doped region of the second doped region is greater than or equal to 50 nm, and the thickness of at least one of the top doped region and the bottom doped region is greater than or equal to 50 nm.

Beneficial effects of the application: multiple PN junctions in different directions are designed in the ridge waveguide, the range of the depletion region is expanded, the modulation efficiency is effectively improved, the optical loss is reduced, and no additional parasitic capacitance is introduced to avoid additional capacitance Affects modulation bandwidth.

Description of drawings

Figure 1 is a schematic diagram of the doping structure of a commonly used ridge waveguide;

FIG. 2 is a schematic diagram of the electro-optic modulator of Embodiment 1 of the present application;

3 is a schematic diagram of the doping structure of the ridge waveguide in Example 1 of the present application;

Fig. 4 is a schematic diagram of cross section A-A in Fig. 3;

Fig. 5 is a schematic diagram of longitudinal section B-B in Fig. 3;

FIG. 6 is a schematic diagram of the doping structure of the ridge waveguide in Example 2 of the present application;

FIG. 7 is a schematic diagram of the doping structure of the ridge waveguide in Example 3 of the present application;

FIG. 8 is a schematic diagram of the doping structure of the ridge waveguide in Example 4 of the present application;

FIG. 9 is a schematic diagram of the doping structure of the ridge waveguide in Example 5 of the present application;

FIG. 10 is a schematic diagram of the doping structure of the ridge waveguide in Embodiment 6 of the present application;

Fig. 11 is a schematic diagram of cross section C-C in Fig. 10;

FIG. 12 is a schematic diagram of the doping structure of the ridge waveguide in Example 7 of the present application;

Fig. 13 is a schematic diagram of cross section D-D in Fig. 12;

FIG. 14 is a schematic diagram of an electro-optic modulator according to Embodiment 8 of the present application.

Detailed ways

The application will be described in detail below in conjunction with specific implementations shown in the accompanying drawings. However, these implementations do not limit the present application, and any structural, method, or functional changes made by those skilled in the art based on these implementations are included in the protection scope of the present application.

In each drawing of the present application, some dimensions of structures or parts are exaggerated relative to other structures or parts for convenience of illustration, and therefore, are only used to illustrate the basic structure of the subject matter of the present application.

In addition, terms used herein such as "upper", "above", "under", "below", etc. to express relative positions in space are for convenience of description to describe a unit or feature as shown in the drawings relative to A relationship to another cell or feature. The terms of spatial relative position may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. When an element or layer is referred to as being "on," "connected to" another element or layer, it can be directly on, connected to, or Intervening elements or layers may be present.

Example 1

As shown in FIGS. 2-5 , the electro-optic modulator of this embodiment at least includes a ridge waveguide 10 and two electrodes 20 . Wherein, the ridge waveguide 10 includes a ridge portion 11 and flat plate portions 12 on both sides of the ridge portion 11 . The ridge waveguide 10 is provided with a first doped region 13 and a second doped region 14. In this embodiment, the first doped region 13 is P-type doped, and the second doped region 14 is N-type doped. Of course , in other embodiments, it is also possible that the first doped region 13 is N-type doped, and the second doped region 14 is P-type doped. The above-mentioned first doped region 13 includes a vertical region 132 and a horizontal region 131 arranged in the ridge portion 11 and extending along the extension direction of the ridge portion 11 (as shown in the y-axis direction), and along the ridge portion 11 A plurality of vertical regions 133 arranged at intervals in the extending direction, the plurality of vertical regions 133 extending into the flat plate portion 12 on one side of the ridge portion 11 along a direction perpendicular to the extending direction of the ridge portion 11 (that is, the x-axis direction in the figure) . The horizontal region 131 and the vertical region 132 of the above-mentioned first doped region 13 constitute the central doped region of the first doped region 13, the bottoms of the horizontal region 131 and the vertical region 132 are higher than the bottom of the ridge waveguide 10, and the horizontal region 131 The width of the vertical region 133 is smaller than the width of the ridge portion 11, and the vertical region 133 can also be called a vertical doped region. The second doped region 14 includes the portion of the ridge portion 11 other than the above-mentioned first doped region 13 , and extends to the flat plate portion 12 on the other side opposite to the vertical region 133 , mainly including the portion located on the ridge portion 11 The two side doped regions located on both sides of the central doped region of the first doped region 13, and the bottom doped region located below the central doped region. In other embodiments, the first doped region 13 may also A top doped region of the second doped region is disposed above the middle doped region. The two side doped regions of the second doped region are connected through the bottom doped region or the top doped region. The second doped region 14 adjoins the horizontal region 131 , the vertical region 132 and the vertical region 133 of the first doped region 13 to form a PN junction including the horizontal direction P1 , the vertical direction P2 and the vertical direction P3 respectively. Here, the horizontal area 131 is parallel to the illustrated xy plane, the vertical area 132 is parallel to the illustrated yz plane, and the vertical area 133 is parallel to the illustrated xz plane.

The slab portion 12 of the ridge waveguide 10 is further provided with a first heavily doped region 16 outside the vertical region 133 of the first doped region 13 and a second heavily doped region 17 outside the second doped region 14 . Wherein, the first heavily doped region 16 is connected to the end of the vertical region 133 of the first doped region 13, and the doping type of the first heavily doped region 16 is the same as that of the first doped region 13, and its doping concentration is high The doping concentration in the first doped region 13 . The second heavily doped region 17 is connected to the second doped region 14, and the doping type of the second heavily doped region 17 is the same as that of the second doped region 14, and its doping concentration is higher than that of the second doped region 14. doping concentration. In this embodiment, the doping concentrations of the first doped region 13 and the second doped region 14 are in the range of 1×10 ¹⁷ cm ⁻³ to 9×10 ¹⁸ cm ⁻³ ; the first heavily doped region 16 and the second doped region The doping concentration of the doubly doped region 17 is in the range of 5×10 ¹⁹ cm ⁻³ to 1×10 ²¹ cm ⁻³ . The first heavily doped region 16 and the second heavily doped region 17 are electrically connected to the two electrodes 20 through conductive vias 30 and the like. During operation, electrical signals are applied through the two electrodes 20 respectively, so that the first heavily doped region 16 is at a lower potential, and the second heavily doped region 17 is at a higher potential. The first heavily doped region 16 applies a low potential to the first doped region 13 through each vertical region 133 of the first doped region 13 , and the second heavily doped region 17 applies a high potential to the second doped region 14 In the above, depletion regions are generated at the PN junctions in the horizontal direction P1, the vertical direction P2 and the vertical direction P3, so that the effective refractive index of the optical signal propagating in the ridge waveguide is changed, thereby changing the phase of the optical signal, and realizing Modulation of optical signals. In the optical modulator of this embodiment, multiple PN junctions in different directions are designed in the ridge waveguide, and there are PN junctions in the horizontal direction, the vertical direction and the vertical direction, which expands the range of the depletion region and effectively improves the modulation efficiency.

In this embodiment, the bottoms of the horizontal region 131 and the vertical region 132 of the first doped region 13 are higher than the bottom of the ridge waveguide 10, and the width L of the horizontal region 131 is smaller than the width of the ridge portion 11 and larger than that of the vertical region 132. Width, in other embodiments, the width L of the horizontal region 131 may also be equal to the width of the vertical region 132 , that is, the cross section formed by the horizontal region 131 and the vertical region 132 is a rectangle. That is, the second doped region 14 on both sides and the bottom of the first doped region 13 is mutually conductive, so that the electrode 20 connected to the second doped region 14 only needs to be arranged on one side of the ridge portion 11, which is different from the commonly used The electrode of the electro-optic modulator designed by PN junction is common, and no additional parasitic capacitance will be introduced to prevent the additional capacitance from affecting the modulation bandwidth. Although increasing the number of PN junctions will affect the junction capacitance, the required extinction ratio and bandwidth, as well as smaller optical losses, can be obtained by designing an appropriate modulation length.

In this embodiment, the bottom of the horizontal region 131 and the vertical region 132 of the first doped region 13 is higher than the bottom of the ridge waveguide 10 by at least 50 nm, that is, the bottom of the second doped region 14 below the first doped region 13 The thickness H1 is still at least 50 nm, forming a PN junction in the horizontal direction P1 with the horizontal region 131 of the first doped region 13 , where the thickness H2 of the horizontal region 131 of the first doped region 13 is greater than or equal to 30 nm. The second doped regions 14 on both sides of the first doped region 13 respectively form PN junctions in the vertical direction P2 and the vertical direction P3 with the vertical region 132 and the vertical region 133 of the first doped region 13 . In this embodiment, the horizontal region 131 of the first doped region 13 is located on both sides of the bottom of the vertical region 132 , and together with the vertical region 132 forms a doped region with a cross-section of “⸄” shape. The upper and lower surfaces of the horizontal region 131 are adjacent to the second doped region 14 , forming two opposite PN junctions in the horizontal direction P1 . The vertical region 132 is also respectively adjacent to the second doped region 14 on both sides thereof, forming two PN junctions facing away from each other in the vertical direction P2. Each vertical region 133 is also adjacent to the second doped region 14 before and after it respectively, forming two PN junctions with back-to-back vertical directions P3, and forming multiple pairs of back-to-back vertical directions P3 at intervals in the extending direction of the ridge portion 11 PN junction. In this embodiment, a plurality of vertical regions 133 are arranged at equal intervals along the extending direction of the ridge portion 11 , and the duty ratio of the vertical regions 133 is 20%-80%. The slab portion 12 between the vertical regions 133 is an intrinsic region 15, and the extension length of the vertical region extending into the slab portion, that is, the width D of the intrinsic region 15, is greater than or equal to 500 nm, that is, the first heavily doped region 16 to the second The distance D between the two doped regions 14 is at least 500 nm to minimize optical loss. Of course, in other embodiments, the intrinsic region 15 can also be lightly doped and replaced by the first lightly doped region. The doping type of the first lightly doped region is the same as that of the first doped region, and its doping concentration is In the range of 1×10 ¹⁶ cm ^-3 to 1×10 ¹⁷ cm ^-3 .

Example 2

As shown in Figure 6, different from Embodiment 1, the horizontal region of the first doped region in this embodiment is only set on one side of the bottom of the vertical region, forming an "L"-shaped cross-section together with the vertical region. doped region. The upper and lower surfaces of the horizontal region are also adjacent to the second doped region, forming two opposite PN junctions in the horizontal direction. The vertical regions are also respectively adjacent to the second doped regions on both sides thereof, forming two back-to-back PN junctions in the vertical direction. Each vertical region is also adjacent to the second doped region before and after it respectively, forming two back-to-back vertical PN junctions, and multiple pairs of back-to-back vertical PN junctions are formed at intervals in the extending direction of the ridge portion. In this embodiment, the horizontal zone is set on the right side of the vertical zone. In other embodiments, the horizontal zone can also be set on the left side of the vertical zone, and the cross section together with the vertical zone is formed as an inverted "L" shape. doped region.

Example 3

As shown in Figure 7, different from Embodiment 1, the horizontal region 131 of the first doped region 13 in this embodiment is only set on one side of the middle part of the vertical region 132, forming a cross section together with the vertical region 132. It is a doped region similar to a horizontal "T" type. Equally, the bottom of the vertical region 132 is higher than the bottom of the ridge waveguide 10 by at least 50nm, that is, there is at least a 50nm thick second doped region 14 below the first doped region 13 to conduct the two sides of the first doped region 13. The second doped region 14 on the side. The upper and lower surfaces of the above-mentioned horizontal region 131 are also adjacent to the second doped region 14 , forming two PN junctions facing away from each other in the horizontal direction. The vertical region 132 is also respectively adjacent to the second doped region 14 on both sides thereof, forming two back-to-back PN junctions in the vertical direction. Each vertical region 133 is also adjacent to the second doped region 14 before and after it respectively, forming two back-to-back vertical PN junctions, and forming multiple pairs of back-to-back vertical PN junctions in the extending direction of the ridge portion 11 at intervals. Knot. In this embodiment, the horizontal area 131 is set on the left side of the vertical area 132 , and in other embodiments, the horizontal area 131 can also be set on the right side or both sides of the vertical area 132 .

Example 4

As shown in Figure 8, different from Embodiment 1, the horizontal region 131 of the first doped region 13 in this embodiment is divided into two parts, one part is set on the left top of the vertical region 132, and the other part is set on the vertical region 132. The right bottom of the region 132 forms a doped region with a “Z” cross-section together with the vertical region 132 . The bottom part of the horizontal region 131 at the top is adjacent to the second doped region 14, forming a single horizontal PN junction, and the upper and lower surfaces of the part of the horizontal region 131 at the bottom are also adjacent to the second doped region 14, forming two rear surfaces. P-N junctions in the horizontal direction. The vertical region 132 is also respectively adjacent to the second doped region 14 on both sides thereof, forming two back-to-back PN junctions in the vertical direction. Each vertical region 133 is also adjacent to the second doped region 14 before and after it respectively, forming two back-to-back vertical PN junctions, and forming multiple pairs of back-to-back vertical PN junctions in the extending direction of the ridge portion 11 at intervals. Knot.

Of course, in other embodiments, the horizontal region of the first doped region can also have different deformations, and its number is not limited. "Tu" type, "Wang" type or "T" type, "E" type, etc.

Example 5

As shown in FIG. 9 , the electro-optic modulator of this embodiment includes a ridge waveguide 10 and two electrodes, and the first heavily doped region and the second heavily doped region on both sides of the ridge waveguide 10 are respectively electrically connected to the two electrodes. Wherein, the ridge waveguide 10 includes a ridge portion 11 and flat plate portions 12 located on both sides of the ridge portion 11 . The ridge waveguide 10 is provided with a first doped region 13 and a second doped region 14, the doping types of the first doped region 13 and the second doped region 14 are opposite, in this embodiment, the first doped region 13 It is P-type doped, and the second doped region 14 is N-type doped. Certainly, in other embodiments, it is also possible that the first doped region 13 is N-type doped, and the second doped region 14 is P-type Doped. Wherein, the first doped region 13 includes a central doped region 134 (which may include a horizontal region and a vertical region) disposed in the ridge portion 11 and extending along the extension direction of the ridge portion 11 (ie, the y-axis direction shown in the figure). ), and a plurality of vertical doped regions 135 arranged at intervals along the extending direction of the ridge portion 11 (same as the vertical regions in the above-mentioned embodiments), the vertical doped regions 135 are along the direction perpendicular to the extending direction of the ridge portion 11 direction (that is, the x-axis direction in the figure) extends to the flat portion 12 on one side of the ridge portion 11 , and the vertical doped region 135 is connected to the central doped region 134 . The above-mentioned second doped region 14 includes two side doped regions 141 located in the ridge portion 11 respectively located on both sides of the middle doped region 134 of the first doped region 13 , and two side doped regions 141 located below the first doped region 13 . The bottom doped region 142 , the two side doped regions 141 are connected through the bottom doped region 142 . The second doped region 14 extends into the flat portion 12 on the other side opposite to the vertical doped region 135 . The two side doped regions 141 of the second doped region 14 are respectively adjacent to the central doped region 134 and the vertical doped region 135 of the first doped region 13, forming a PN junction including a vertical direction P2 and a vertical direction P3; The bottom doped region 142 of the second doped region 14 is adjacent to the middle doped region 134 of the first doped region 13 to form a PN junction in the horizontal direction P1.

As in Embodiment 1, the first heavily doped region outside the ridge waveguide is connected to the end of the vertical doped region 135 of the first doped region 13, and the doping of the first heavily doped region and the first doped region 13 The types are the same, and their doping concentration is higher than that of the first doping region 13 . The second heavily doped region is connected to the second doped region 14, and the doping type of the second heavily doped region is the same as that of the second doped region 14, and its doping concentration is higher than that of the second doped region 14. concentration. During operation, electric signals are applied through the two electrodes respectively, so that the first heavily doped region is at a lower potential, and the second heavily doped region is at a higher potential. The first heavily doped region applies a low potential to the first doped region 13 through the vertical doped regions 135 of the first doped region 13, and the second heavily doped region applies a high potential to the second doped region 14. In the above, depletion regions are generated at the PN junctions in the horizontal direction P1, the vertical direction P2 and the vertical direction P3, so that the effective refractive index of the optical signal propagating in the ridge waveguide is changed, thereby changing the phase of the optical signal, and realizing Modulation of optical signals. In the optical modulator of this embodiment, multiple PN junctions in different directions are designed in the ridge waveguide, and there are PN junctions in the horizontal direction, the vertical direction and the vertical direction, which expands the range of the depletion region and effectively improves the modulation efficiency.

In this embodiment, the width d of the side doped 141 region of the second doped region 14 is greater than or equal to 50 nm, the thickness h of the bottom doped region 142 is greater than or equal to 50 nm, and the two side doped regions 141 pass through the bottom doped region 142 connected. That is, the second doped region 14 on both sides and the bottom of the first doped region 13 are mutually conductive, so that the electrodes electrically connected to the second doped region 14 only need to be arranged on one side of the ridge portion 11, which is different from the commonly used The electrode of the electro-optic modulator designed by PN junction is common, and no additional parasitic capacitance will be introduced to prevent the additional capacitance from affecting the modulation bandwidth. Although increasing the number of PN junctions will affect the junction capacitance, the required extinction ratio and bandwidth, as well as smaller optical losses, can be obtained by designing an appropriate modulation length.

Same as the embodiment, in this embodiment, a plurality of vertical doped regions 135 are arranged at equal intervals along the extending direction of the ridge portion 11 , and the duty ratio of the vertical doped regions 135 is 20%-80%. The flat plate portion 12 between the vertical doped regions 135 is an intrinsic region 15, and the width D of the intrinsic region 15 is greater than or equal to 500 nm, that is, the distance D between the first heavily doped region and the second doped region 14 At least 500nm to minimize optical loss. Of course, in other embodiments, the intrinsic region 15 can also be lightly doped and replaced by the first lightly doped region. The doping type of the first lightly doped region is the same as that of the first doped region, and its doping concentration is less than the doping concentration of the first doped region.

In this embodiment, the cross-section of the central doped region 134 of the first doped region 13 is a rectangle. In other embodiments, the central doped region 134 of the first doped region 13 may also include a vertical region and a horizontal region. , the vertical area is connected with the horizontal area to form a cross-section in the shape of "ten", "tu", "dry", "wang", "丄" or "T", "E" "Type, "L" type, "Z" type, etc. The horizontal region of the middle doped region is adjacent to the bottom doped region of the second doped region to form a horizontal PN junction, and the vertical region of the middle doped region is adjacent to the two side doped regions of the second doped region to form a vertical junction. For vertical PN junctions, vertical doped regions are arranged at intervals in one of the side doped regions of the second doped region, and a plurality of vertical PN junctions are formed adjacent to the side doped regions.

Example 6

As shown in Figures 10 and 11, as in Embodiment 5, in this embodiment, the first doped region 13 includes a doped region 13 arranged in the ridge portion 11 and along the extending direction of the ridge portion 11 (that is, the y-axis direction shown in the figure). ) an extended central doped region 134 (may include a horizontal region and a vertical region), and a plurality of vertical doped regions 135 arranged at intervals along the extending direction of the ridge portion 11 (same as the vertical regions in the above-mentioned embodiments), The vertical doped region 135 extends to the flat plate portion 12 on one side of the ridge portion 11 along the direction perpendicular to the extending direction of the ridge portion 11 (that is, the x-axis direction in the figure), and the vertical doped region 135 and the central doped region 134 connected.

The difference from Embodiment 5 is that in this embodiment, the second doped region 14 includes two side doped regions located in the ridge portion 11 on both sides of the middle doped region 134 of the first doped region 13 141 , and a top doped region 143 located above the first doped region 13 , and the two side doped regions 141 are connected through the top doped region 143 . The second doped region 14 extends into the flat portion 12 on the other side opposite to the vertical doped region 135 . The two side doped regions 141 of the second doped region 14 are respectively adjacent to the central doped region 134 and the vertical doped region 135 of the first doped region 13, forming a PN junction including a vertical direction P2 and a vertical direction P3; The top doped region 143 of the second doped region 14 is adjacent to the middle doped region 134 of the first doped region 13 to form a PN junction in the horizontal direction P1.

In this embodiment, the width d of the side doped 141 region of the second doped region 14 is greater than or equal to 50 nm, the thickness h of the top doped region 143 is greater than or equal to 50 nm, and the two side doped regions 141 pass through the top doped region 143 connected. That is, the second doped region 14 on both sides and the top of the first doped region 13 are mutually conductive, so that the electrodes electrically connected to the second doped region 14 only need to be arranged on one side of the ridge portion 11, which is different from the commonly used The electrode of the electro-optic modulator designed by PN junction is common, and no additional parasitic capacitance will be introduced to prevent the additional capacitance from affecting the modulation bandwidth. Although increasing the number of PN junctions will affect the junction capacitance, the required extinction ratio and bandwidth, as well as smaller optical losses, can be obtained by designing an appropriate modulation length. In this embodiment, the height of the vertical doped region 135 of the first doped region 13 is the same as the height of the side doped region 141 of the second doped region 14, extending into the top doped region of the second doped region 14 In 143, the top doped region 143 of the second doped region 14 is divided into a comb-like structure, and the vertical doped region 135 is also adjacent to the top doped region 143 to form a PN junction in the vertical direction, which increases the PN junction in the vertical direction. area.

Example 7

As shown in Figures 12 and 13, different from Embodiment 6, in this embodiment, the height of the vertical doped region 135 of the first doped region 13 is lower than the height of the doped region 141 on the side of the second doped region 14 , which is equal to the height of the doped region 134 in the middle of the first doped region 13 . The doping structure is relatively simple and convenient for production.

In Embodiment 5-7, the second doped region includes two side doped regions and a top doped region or a bottom doped region. In other embodiments, the second doped region may also include a bottom doped region at the same time. region and top doped region. The bottom doped region and the top doped region can be connected to two side doped regions at the same time, or one of the top doped region and the bottom doped region is connected to two side doped regions at the same time, and the other is connected to at least one of the side doped regions. Miscellaneous area.

Example 8

As shown in FIG. 14 , different from Embodiment 1, the ridge waveguide of the electro-optic modulator in this embodiment further includes a first moderately doped region 18 and a second moderately doped region 19 . Wherein, the first moderately doped region 18 is located between the first doped region 13 and the first heavily doped region 16 , and is connected to the end of the vertical region 133 . The doping type of the first moderately doped region 18 is the same as that of the first doped region 13, and its doping concentration is higher than that of the first doped region 13 and lower than that of the first heavily doped region 16. concentration. The second moderately doped region 19 is located between the second doped region 14 and the second heavily doped region 17, the doping type of the second moderately doped region 19 is the same as that of the second doped region 14, and its doping concentration is The doping concentration is higher than that of the second doped region 14 and lower than that of the second heavily doped region 17 . Here, the doping concentrations of the first doped region 13 and the second doped region 14 are in the range of 1×10 ¹⁷ cm ⁻³ to 9×10 ¹⁸ cm ⁻³ , and the first moderately doped region 18 and the second moderately doped The doping concentration of the impurity region 19 is in the range of 1×10 ¹⁸ cm ^-3 to 9×10 ¹⁹ cm ^-3 , and the doping concentration of the first heavily doped region 16 and the second heavily doped region 17 is 5×10 ¹⁹ cm ^-3 ~ 1×10 ²¹ cm ^-3 range.

In this embodiment, the extension length of the vertical region 133 of the first doped region 13 into the flat part, that is, the width D of the intrinsic region 15, is in the range of 0 to 500 nm, that is, the first middle doped region 18 to the second The distance D between the doped regions 14 is in the range of 0-500 nm. In other embodiments, the intrinsic region 15 can also be lightly doped and replaced by a first lightly doped region, the doping type of the first lightly doped region is the same as that of the first doped region, and its doping concentration is between 1 In the range of ×10 ¹⁶ cm ^-3 to 1×10 ¹⁷ cm ^-3 .

In the above embodiments, the width of the ridge portion of the ridge waveguide is preferably in the range of 300-600 nm, the P-type doping is preferably boron as the doping impurity, and the N-type doping is preferably phosphorus as the doping impurity.

The series of detailed descriptions listed above are only specific descriptions of the feasible implementation modes of the application, and they are not intended to limit the protection scope of the application. Any equivalent implementation mode or All changes should be included within the scope of protection of this application.

Claims (17)

1. An electro-optic modulator, characterized in that: it comprises a ridge waveguide, and the ridge waveguide includes a ridge portion and flat plate portions located on both sides of the ridge portion; A first doped region and a second doped region are provided in the ridge waveguide, and the doping type of the first doped region is opposite to that of the second doped region; The first doped region includes a vertical region and a horizontal region arranged in the ridge portion and extending along the extending direction of the ridge portion, and a plurality of intervals arranged along the extending direction of the ridge portion a vertical area, the vertical area extends into the flat plate portion on one side of the ridge portion along a direction perpendicular to the extending direction of the ridge portion; The horizontal area, the vertical area and the vertical area are connected together, the bottoms of the horizontal area and the vertical area are higher than the bottom of the ridge waveguide, and the width of the horizontal area is smaller than that of the ridge waveguide. the width of the section; The second doped region includes a portion of the ridge portion except the first doped region, and the second doped region extends into a flat plate portion on the other side opposite to the vertical region; The second doped region is adjacent to the horizontal region, the vertical region and the vertical region of the first doped region to form a PN junction including the horizontal direction, the vertical direction and the vertical direction, respectively. 2. The electro-optic modulator according to claim 1, wherein the horizontal region of the first doped region is located at the bottom, middle or top of the vertical region. 3. The electro-optic modulator according to claim 2, wherein the horizontal region of the first doped region is located on one side or both sides of the vertical region. 4. The electro-optic modulator of claim 1, wherein the bottoms of the horizontal and vertical regions of the first doped region are at least 50 nm higher than the bottom of the ridge waveguide. 5. The electro-optic modulator according to claim 1, wherein the thickness of the horizontal region of the first doped region is greater than or equal to 30 nm. 6. The electro-optic modulator according to claim 1, wherein the plurality of vertical regions are arranged at equal intervals along the extending direction of the ridge portion. 7. The electro-optic modulator according to claim 6, wherein the duty cycle of the vertical region is 20%-80%. 8. The electro-optic modulator according to claim 1, characterized in that: the slab portion where the vertical region is located is an intrinsic region or a first lightly doped region; the first lightly doped region and the first lightly doped region The doping type of the doped regions is the same. 9. The electro-optic modulator according to claim 1, wherein the width of the horizontal region is greater than or equal to the width of the vertical region. 10. The electro-optic modulator according to any one of claims 1-9, characterized in that: The ridge waveguide also includes a first heavily doped region and a second heavily doped region: The first heavily doped region is located outside the vertical region of the first doped region and connected to the end of the vertical region, the first heavily doped region is of the same doping type as the first doped region, Its doping concentration is higher than that of the first doping region; The second heavily doped region is located outside the second doped region and connected to the second doped region, and the second heavily doped region has the same doping type as the second doped region, which a doping concentration higher than that of the second doping region; The electro-optic modulator further includes at least two electrodes, and the first heavily doped region and the second heavily doped region are respectively electrically connected to the two electrodes. 11 . The electro-optic modulator according to claim 10 , wherein the extension length of the vertical region into the flat plate portion is greater than or equal to 500 nm. 12. The electro-optic modulator according to claim 10, characterized in that: The ridge waveguide also includes a first middle doped region and a second middle doped region: The first moderately doped region is located between the first doped region and the first heavily doped region, and is connected to the end of the vertical region, and the first moderately doped region is connected to the first heavily doped region. The doping types of the doped regions are the same, and their doping concentration is higher than that of the first doped region and lower than that of the first heavily doped region; The second moderately doped region is located between the second doped region and the second heavily doped region, and the doping type of the second moderately doped region is the same as that of the second doped region, Its doping concentration is higher than that of the second doped region and lower than that of the second heavily doped region. 13 . The electro-optic modulator according to claim 12 , wherein the extension length of the vertical region into the flat plate portion is between 0 nm and 500 nm. 14 . 14. An electro-optic modulator, characterized in that it comprises a ridge waveguide, and the ridge waveguide includes a ridge portion and flat plate portions located on both sides of the ridge portion; A first doped region and a second doped region are provided in the ridge waveguide, and the doping type of the first doped region is opposite to that of the second doped region; The first doped region includes a middle doped region arranged in the ridge portion and extending along the extension direction of the ridge portion, and a plurality of vertical doped regions arranged at intervals along the extension direction of the ridge portion. impurity region, the vertical doped region extends into the flat plate on one side of the ridge along a direction perpendicular to the extending direction of the ridge; the vertical doped region is connected to the central doped region ; The second doped region includes two side doped regions located in the ridge portion on both sides of the central doped region of the first doped region, and located above the first doped region. The top doped region and/or the bottom doped region below; the two side doped regions are connected by the top doped region and/or the bottom doped region; the second doped region extends to the The second doped region is adjacent to the first doped region to form a PN junction including a horizontal direction, a vertical direction and a vertical direction. 15. The electro-optical modulator according to claim 14, characterized in that: the cross-section of the central doped region of the first doped region is rectangular; or the central doped region of the first doped region comprises vertical A vertical zone and a horizontal zone, the vertical zone and the horizontal zone are connected. 16. The electro-optical modulator according to claim 14, characterized in that: the slab portion where the vertically doped region is located is an intrinsic region or a first lightly doped region; the first lightly doped region and the The doping types of the first doped regions are the same. 17. The electro-optical modulator according to claim 14, characterized in that: the width of the side doped region of the second doped region is greater than or equal to 50 nm, and the width of the top doped region and the bottom doped region At least one of the thicknesses is greater than or equal to 50 nm.

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