Micro-ring modulator and forming method thereof

Abstract

The embodiment of the invention provides a micro-ring modulator and a forming method thereof, and the micro-ring modulator comprises a straight waveguide and an annular waveguide coupled with the straight waveguide. The annular waveguide comprises a low-power-consumption control part which comprises a first doped region and a second doped region which are arranged along a first direction and are opposite in doping type; the projection of the interface of the first doped region and the second doped region in the second direction is bent; the high-speed modulation part comprises a third doped region and a fourth doped region which are arranged along the first direction and have opposite doping types; and the coupling waveguide part is connected with the low-power-consumption control part and the high-speed modulation part and is positioned on one side of the straight waveguide.

Description

Technical Field

[0001] The present disclosure relates to the field of integrated optical devices, and in particular to a micro-ring modulator and a method for forming the same. Background Art

[0002] Micro-ring modulator is a commonly used structure in high-speed modulators. By confining the optical signal in a resonant cavity with a high quality factor (Q), the optical path length can be effectively increased, thereby increasing the interaction of the modulated carrier distribution. However, changes in ambient temperature during operation will cause the resonant wavelength of the resonant cavity in the micro-ring modulator to shift, thereby degrading the performance of the micro-ring modulator.

[0003] In the related art, the micro-ring modulator usually needs to add thermocouple modulation to actively control the working state of the micro-ring modulator; however, the introduction of thermocouples will cause the overall power consumption of the micro-ring modulator to be huge (15-20mW), which reduces the energy utilization efficiency of the micro-ring modulator and is not conducive to improving the modulation efficiency of the micro-ring modulator. Summary of the invention

[0004] In view of this, an embodiment of the present disclosure provides a micro-ring modulator and a method for forming the same.

[0005] In a first aspect, an embodiment of the present disclosure provides a micro-ring modulator, comprising: a straight waveguide, and a ring waveguide coupled to the straight waveguide; wherein the ring waveguide comprises:

[0006] The low power consumption control part comprises a first doping region and a second doping region arranged along a first direction and having opposite doping types; the projection of the interface between the first doping region and the second doping region in the second direction is a bent shape;

[0007] a high-speed modulation portion, comprising a third doping region and a fourth doping region arranged along the first direction and having opposite doping types;

[0008] A coupling waveguide part connected to the low power consumption control part and the high speed modulation part and located at one side of the straight waveguide;

[0009] The first direction is a direction extending outward from the center of the ring waveguide, and the second direction intersects with the plane where the micro-ring modulator is located.

[0010] In some embodiments, the low power consumption control portion further includes: an intrinsic region;

[0011] The intrinsic region is located between the first doping region and the second doping region, and a projection of the intrinsic region in the second direction is the bent shape.

[0012] In some embodiments, the annular waveguide is a ridge-shaped structure, which includes a ridge portion and flat plate portions located on both sides of the ridge portion along the first direction; wherein the bend is located on the ridge portion.

[0013] In some embodiments, a dimension of the bend in the first direction is smaller than or equal to a dimension of the ridge in the first direction.

[0014] In some embodiments, the bend shape includes at least a rectangular bend, a V-shaped bend, a U-shaped bend or an S-shaped bend.

[0015] In some embodiments, the first doped region includes a first lightly doped region and a first heavily doped region located on a side of the first lightly doped region close to the center of the ring waveguide;

[0016] The second doped region includes a second lightly doped region and a second heavily doped region located at a side of the second lightly doped region away from the center of the ring waveguide.

[0017] In some embodiments, the low power consumption control part further includes:

[0018] a first electrode connected to the first heavily doped region;

[0019] The second electrode is connected to the second heavily doped region.

[0020] In some embodiments, a projection of an interface between the third doping region and the fourth doping region in the second direction is an arc, and the arc is located on the ridge;

[0021] The third doped region includes a third lightly doped region and a third heavily doped region located on a side of the third lightly doped region close to the center of the ring waveguide;

[0022] The fourth doped region includes a fourth lightly doped region and a fourth heavily doped region located at a side of the fourth lightly doped region away from the center of the ring waveguide.

[0023] In some embodiments, the high speed modulation part further comprises:

[0024] a third electrode connected to the third heavily doped region;

[0025] A fourth electrode is connected to the fourth heavily doped region.

[0026] In a second aspect, an embodiment of the present disclosure provides a method for forming a micro-ring modulator, the method comprising:

[0027] providing a semiconductor substrate;

[0028] Etching the semiconductor substrate to form a straight waveguide and an initial ring waveguide located on one side of the straight waveguide;

[0029] The initial ring waveguide is ion doped to form a ring waveguide; wherein the ring waveguide includes a low power consumption control part, a high speed modulation part and a coupling waveguide part.

[0030] The disclosed embodiment provides a micro-ring modulator and a method for forming the same, wherein the micro-ring modulator includes: a straight waveguide, and a ring waveguide coupled with the straight waveguide; wherein the ring waveguide includes: a low-power control portion, including a first doping region and a second doping region arranged along a first direction and having opposite doping types; the projection of the interface of the first doping region and the second doping region in the second direction is a bent shape; a high-speed modulation portion, including a third doping region and a fourth doping region arranged along the first direction and having opposite doping types; a coupling waveguide portion, connected to the low-power control portion and the high-speed modulation portion, and located on one side of the straight waveguide. Here, since the low-power control portion is composed of the first doping region and the second doping region of opposite doping types, the low-power control portion can realize zero-power modulation under reverse bias, or realize low-power modulation under forward voltage, thereby reducing the power consumption during optical signal modulation; further, since the interface between the first doping region and the second doping region is a bent shape, the contact surface between the first doping region and the second doping region is increased, thereby increasing the length of the optical signal modulation area (i.e., the optical path length), thereby increasing the interaction of the modulated carrier distribution, and improving the modulation efficiency of the optical signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of a micro-ring modulator provided in an embodiment of the present disclosure Figure 1 ;

[0032] Figure 2 A schematic diagram of a micro-ring modulator provided in an embodiment of the present disclosure Figure 2 ;

[0033] Figure 3 A schematic diagram of a micro-ring modulator provided in an embodiment of the present disclosure Figure 3 ;

[0034] Figure 4 A schematic diagram of a micro-ring modulator provided in an embodiment of the present disclosure Figure 4 ;

[0035] Figure 5 A schematic diagram of a micro-ring modulator provided in an embodiment of the present disclosure Figure 5 ;

[0036] Figure 6 A schematic diagram of a micro-ring modulator provided in an embodiment of the present disclosure Figure 6;

[0037] Figure 7 A schematic diagram of a micro-ring modulator provided in an embodiment of the present disclosure Figure 7 ;

[0038] Figure 8 A schematic diagram of a micro-ring modulator provided in an embodiment of the present disclosure Figure 8 ;

[0039] Fig. 9 A schematic diagram of a micro-ring modulator provided in an embodiment of the present disclosure Figure 9 ;

[0040] Fig.10 A schematic diagram of a top view of a partially rectangular bend provided in an embodiment of the present disclosure;

[0041] Fig.11 A schematic diagram of a micro-ring modulator provided in an embodiment of the present disclosure Figure 10 ;

[0042] Fig.12 A schematic diagram of a method for forming a micro-ring modulator provided in an embodiment of the present disclosure;

[0043] Fig.13 A schematic diagram of a formation process of a micro-ring modulator provided in an embodiment of the present disclosure Figure 1 ;

[0044] Fig.14 A schematic diagram of a formation process of a micro-ring modulator provided in an embodiment of the present disclosure Figure 2 ;

[0045] Fig.15 A schematic diagram of the working principle of the micro-ring modulator provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. It is understood that the specific embodiments described herein are only used to explain the relevant disclosure, rather than to limit the disclosure. It should also be noted that, for the convenience of description, only the parts related to the relevant disclosure are shown in the drawings.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present disclosure belongs. The terms used herein are only for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure.

[0048] In the following description, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0049] It should be pointed out that the terms "first\second\third" involved in the embodiments of the present disclosure are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of the present disclosure described here can be implemented in an order other than that illustrated or described here.

[0050] At present, with the rise of new applications such as artificial intelligence generated content (AIGC) and cloud computing, short-distance optical interconnection links in data centers require higher transmission rates, more ports, and lower power consumption. Among them, high-speed electro-optical modulators are the core components in optical interconnection links, which are used to complete the conversion of electrical signals to optical signals.

[0051] Furthermore, the micro-ring modulator is a commonly used structure in high-speed modulators. The diameter of the micro-ring modulator is about 10 micrometers (μm), which is much smaller than the Mach-Zehnder modulator that is more than 2 mm long. By confining the optical signal in a resonant cavity with a quality factor (Q) through a micro-ring modulator, the optical path length can be effectively increased, thereby increasing the interaction of the modulated carrier distribution; where the wavelength in the resonant cavity is determined by 2πRneff=mλ, where 2πR is the circumference of the micro-ring resonator, neff is the effective refractive index of the waveguide, m is the order of resonance, and λ is the wavelength of the light wave.

[0052] Since the effective refractive index of the waveguide is temperature-dependent, changes in ambient temperature can cause the resonant wavelength of the resonant cavity in the microring modulator to shift, thereby degrading the performance of the microring modulator. In related technologies, microring modulators usually require the addition of thermocouple modulation to actively control the working state of the microring; however, the introduction of thermocouples results in a huge overall power consumption of the microring modulator (15-20mW), which is not conducive to reducing the efficiency of photoelectric conversion.

[0053] Based on this, the embodiment of the present disclosure provides a micro-ring modulator and a method for forming the same, wherein the micro-ring modulator includes: a straight waveguide, and a ring waveguide coupled to the straight waveguide; wherein the ring waveguide includes: a low-power control portion, including a first doping region and a second doping region arranged in a first direction and having opposite doping types; the projection of the interface of the first doping region and the second doping region in the second direction is a bent shape; a high-speed modulation portion, including a third doping region and a fourth doping region arranged in the first direction and having opposite doping types; a coupling waveguide portion, connected to the low-power control portion and the high-speed modulation portion, and located on one side of the straight waveguide. Here, since the low-power control portion is composed of the first doping region and the second doping region of opposite doping types, the low-power control portion can realize zero-power modulation under reverse bias, or realize low-power modulation under forward voltage, thereby reducing the power consumption during optical signal modulation; further, since the interface between the first doping region and the second doping region is bent, the contact surface between the first doping region and the second doping region is increased, thereby increasing the length of the optical signal modulation area (i.e., the optical path length), thereby increasing the interaction of the modulated carrier distribution, and improving the modulation efficiency of the optical signal.

[0054] Before introducing the embodiments of the present disclosure, two directions that may be used in the following embodiments to describe the three-dimensional structure are defined. The direction extending outward from the center of the ring waveguide on the plane where the micro-ring modulator is located is defined as the first direction; the direction intersecting (e.g., perpendicular) to the plane where the micro-ring modulator is located is defined as the second direction. In the embodiments of the present disclosure, the first direction is defined as the X-axis direction, and the second direction is defined as the Y-axis direction.

[0055] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0056] Figure 1 The present disclosure provides a micro-ring modulator 100 , which includes a straight waveguide 110 and a ring waveguide 120 coupled to the straight waveguide 110 .

[0057] In the disclosed embodiment, the annular waveguide 120 and the straight waveguide 110 transmit optical signals by lateral coupling. It is understood that the annular waveguide 120 and the straight waveguide 110 are in the same plane, the annular waveguide 120 is located on one side of the straight waveguide 110, and there is a coupling gap between the annular waveguide 120 and the straight waveguide 110.

[0058] In the disclosed embodiments, please refer to Figure 1 , the micro-ring modulator 100 includes a straight waveguide 110 and a ring waveguide 120 as an example for description. In other embodiments, the number of the straight waveguides 110 can be multiple, and / or the number of the ring waveguides 120 can be multiple; for example, Figure 2As shown, the micro-ring modulator 100 may include a straight waveguide 100 and two ring waveguides 120 coupled thereto; Figure 3 As shown, the micro-ring modulator 100 may include two straight waveguides 100 and a ring waveguide 120 coupled thereto.

[0059] In the embodiment of the present disclosure, the transmission path of the optical signal is as follows: Figure 1 As shown in the direction of the arrow in the middle; first, the straight waveguide 110 transmits the received optical signal to the area between the straight waveguide 110 and the ring waveguide 120; next, due to the coupling effect between the straight waveguide 110 and the ring waveguide 120, a part of the optical signal will be coupled from the straight waveguide 110 into the ring waveguide 120; finally, the phase, amplitude, etc. of the optical signal are modulated by the ring waveguide 120, and the modulated optical signal is coupled from the ring waveguide 120 back to the straight waveguide 110 for output.

[0060] Please continue to refer to Figure 1 The ring waveguide 120 includes: a low power consumption control part 121, a high speed modulation part 122 and a coupling waveguide part 123; the coupling waveguide part 123 is connected to the low power consumption control part 121 and the high speed modulation part 122, and is located on one side of the straight waveguide 110.

[0061] In the embodiment of the present disclosure, the coupling waveguide portion 123 is a portion of the ring waveguide 120 that is coupled with the straight waveguide 110, and is used to couple the optical signal from the straight waveguide 110 to the ring waveguide 120, and couple the modulated optical signal back to the straight waveguide 110. The number of the coupling waveguide portions 123 is the same as the number of the straight waveguides 110, for example, Figure 1 The number of the coupled waveguide parts 123 is one.

[0062] Please continue to refer to Figure 1 The low power consumption control part 121 includes a first doping region 121a and a second doping region 121b arranged along the X-axis direction and having opposite doping types; the projection of the interface between the first doping region 121a and the second doping region 121b in the Y-axis direction is a bent shape.

[0063] It should be noted that, in order to facilitate the description of the various parts in the ring waveguide 120, the X-axis direction is defined as the direction extending outward from the center of the ring waveguide 120; for example, for the low power control part 121, the X-axis direction refers to the direction from the center of the ring waveguide 120 to the low power control part 121.

[0064] In the embodiment of the present disclosure, since the doping types of the first doping region 121a and the second doping region 121b are opposite, the first doping region 121a and the second doping region 121b can form a PN junction. For example, the doping type of the first doping region 121a can be P-type doping, and the doping type of the second doping region 121b can be N-type doping; wherein the P-type doping region is doped with trivalent impurity elements such as boron, gallium, and indium, and the N-type doping region is doped with pentavalent impurity elements such as phosphorus, antimony, and arsenic.

[0065] In the embodiment of the present disclosure, when a reverse voltage is applied to the low power control part 121 (i.e., the PN junction), the width of the depletion region in the low power control part 121 (i.e., the PN junction) increases as the reverse voltage increases; further, since the width of the depletion region changes, the refractive index of the optical signal in the depletion region changes, so that the refractive index of the optical signal when passing through the low power control part 121 can be changed according to the magnitude of the reverse voltage, thereby achieving modulation of the phase or amplitude of the optical signal. In addition, since there is no static current in the low power control part 121 (i.e., the PN junction) when a reverse voltage is applied to the low power control part 121 (i.e., the PN junction), the low power control part 121 does not generate power consumption, so that the low power control part 121 can achieve zero power modulation under reverse bias.

[0066] In the embodiment of the present disclosure, when a forward voltage is applied to the low power control part 121 (i.e., PN junction), holes in the first doped region 121a (P region) will move to the second doped region 121b (N region), and electrons in the second doped region 121b (N region) will move to the first doped region 121a (P region), and these carriers will recombine in the depletion region of the low power control part 121 (i.e., PN junction). In this process, the carrier concentration on both sides of the low power control part 121 (i.e., PN junction) will increase, causing the refractive index of the low power control part 121 to change; thus, by controlling the magnitude and rate of change of the forward voltage, the amount of carrier injection and the change of the refractive index can be accurately controlled, thereby realizing modulation of the optical signal. In addition, a lower forward voltage can satisfy the movement of carriers, thereby realizing modulation of the optical signal under low power consumption.

[0067] Furthermore, since the interface between the first doped region and the second doped region is bent, the contact area between the first doped region and the second doped region is increased, thereby increasing the length of the depletion region in the low power consumption control part 121 under reverse voltage and forward voltage, making the length of the optical signal modulation area (i.e., the optical path length) longer, thereby increasing the interaction of the modulated carrier distribution and improving the modulation efficiency of the optical signal.

[0068] It should be noted that the number and length of the low power consumption control part 121 (ie, the length along the circumference of the ring waveguide 120) can be set as needed; for example, please refer to Figure 1 , the number of low power control parts 121 is 1; for example, please refer to Figure 4 , the number of low power consumption control parts 121 is 2.

[0069] Please continue to refer to Figure 1 The high-speed modulation portion 122 includes a third doping region 122a and a fourth doping region 122b arranged along the X' axis direction and having opposite doping types.

[0070] In the embodiment of the present disclosure, since the doping types of the third doping region 122a and the fourth doping region 122b are opposite, the third doping region 122a and the fourth doping region 122b can form a PN junction. For example, the doping type of the third doping region 122a can be P-type doping, and the doping type of the fourth doping region 122b can be N-type doping.

[0071] In the disclosed embodiment, an RF (radio frequency) signal is applied to the high-speed modulation part 122 (i.e., the PN junction) to change the carrier distribution in its depletion region. When the RF signal is applied to the high-speed modulation part 122 (i.e., the PN junction), the RF signal causes the width of the depletion region in the high-speed modulation part 122 (i.e., the PN junction) to change periodically, thereby affecting the carrier distribution in the high-speed modulation part 122, and further causing the refractive index of the high-speed modulation part 122 to change periodically, thereby achieving modulation of the optical signal.

[0072] It should be noted that the low power control part 121 in the embodiment of the present disclosure is used to reduce the energy consumption of the ring waveguide during operation, while the high-speed modulation part 122 is used to achieve high-speed modulation of the optical signal; therefore, the low power control part 121 and the high-speed modulation part 122 are both PN junctions, but the voltages applied to the low power control part 121 and the high-speed modulation part 122 are different, which not only improves the energy utilization efficiency of the micro-ring modulator, but also helps to improve the modulation efficiency of the micro-ring modulator.

[0073] It should also be noted that the number and length of the high-speed modulation part 122 (ie, the length along the circumference of the ring waveguide 120) can be set as needed; for example, please refer to Figure 1 , the number of high-speed modulation parts 122 is 1.

[0074] In addition, the connection sequence of the low power consumption control part 121, the high speed modulation part 122 and the coupling waveguide part 123 can be set as needed; for example, Figure 1 As shown, the coupling waveguide part 123 can be connected to the high-speed modulation part 122 and the low-power control part 121 in sequence in a counterclockwise direction, so that the optical signal can be input into the high-speed modulation part 122 and the low-power control part 121 in sequence for modulation.

[0075] In the embodiment of the present disclosure, by setting the interface between the first doped region and the second doped region to be bent, the length of the depletion region in the low power consumption control part 121 is increased, so that the length of the optical signal modulation area (i.e., the optical path length) is increased, thereby doubling the modulation efficiency of the optical signal.

[0076] Next, please refer to Figures 5 to 11 , the micro-ring modulator 100 provided in the embodiment of the present disclosure is introduced in detail.

[0077] In some embodiments, please refer to Figure 5 The low power consumption control part 121 further includes: an intrinsic region 121c; the intrinsic region 121c is located between the first doping region 121a and the second doping region 121b, and its projection in the Y-axis direction is a bent shape.

[0078] In the embodiment of the present disclosure, by adding the intrinsic region 121c, the width of the depletion region between the first doping region 121a and the second doping region 121b is made wider, so that the range of change of the refractive index of the low power control part 121 is larger, thereby widening the wavelength range of the optical signal modulation by the low power control part 121, and the amplitude or intensity change during the optical signal modulation process. In addition, the first doping region 121a, the intrinsic region 121c and the second doping region 121b constitute a PIN junction, and its modulation principle is similar to the modulation principle of the above-mentioned low power control part (PN junction), which will not be repeated here.

[0079] In some embodiments, the bend shape can be a rectangular bend (eg Figure 1 and Figure 5 As shown), V-shaped bend (as shown Figure 6 As shown), U-shaped bend or S-shaped bend (as shown Figure 7 In other embodiments, the bending shape may also be other achievable shapes, which are not limited in the present disclosure. In this way, the degree of freedom in designing the low power consumption control part 121 can be increased.

[0080] The bending shape in the embodiment of the present disclosure refers to: the projection of the interface of the first doping region 121a and the second doping region 121b in the Y-axis direction, or the projection of the intrinsic region 121c in the Y-axis direction is a bending shape; the bending shape in the following text can be understood according to this. In this way, when the optical signal is modulated by the low-power control part 121, the projection of its depletion region in the Y-axis direction is a bending shape, so that the length of the depletion region is longer, thereby increasing the length of the optical signal modulation area (i.e., the optical path length), thereby increasing the interaction of the modulated carrier distribution and improving the modulation efficiency of the optical signal.

[0081] In some embodiments, please refer to Figure 8 and Fig. 9The ring waveguide 120 is a ridge structure, which includes a ridge portion 131 and flat plate portions 132 located on both sides of the ridge portion 131 along the X-axis direction; wherein the bend is located on the ridge portion 131 .

[0082] In the disclosed embodiment, the ring waveguide 120 with a ridge structure helps to gather the energy of the optical signal, so that the optical signal has higher efficiency and stability when modulated in the ring waveguide 120; wherein, the ridge 131 is used to guide the optical signal to propagate in the ring waveguide 120, and the flat portion 132 helps to confine the energy of the optical signal (optical field) within the ridge 131, thereby reducing the leakage and loss of the optical signal. Since the bend is located on the ridge 131, the depletion region (or intrinsic region) of the low power control part 121 is located on the ridge 131, which is conducive to the modulation and propagation of the optical signal in the depletion region, thereby improving the performance of the micro-ring modulator 100.

[0083] In some embodiments, please refer to Figure 8 , the dimension d1 of the bend in the X-axis direction is smaller than the dimension d2 of the ridge 131 in the X-axis direction. In this way, under the forward voltage or the reverse voltage, the depletion region (or the intrinsic region) of the low power consumption control part 121 is located on the ridge 131, which is beneficial to confine the optical signal within the ridge 131 and reduce the leakage and loss of the optical signal.

[0084] In some embodiments, please refer to Fig. 9 , the dimension d1 of the meander in the X-axis direction is equal to the dimension d2 of the ridge 131 in the X-axis direction. In this way, the length of the meander can be made longer, that is, the length of the depletion region (or intrinsic region) of the low power control part 121 is longer, which is beneficial to increase the optical path length of the optical signal in the low power control part 121 and improve the modulation efficiency of the low power control part 121.

[0085] In the embodiment of the present disclosure, within any period of the meander shape, the projection areas of the first doping region 121a and the second doping region 121b in the Y-axis direction are equal. Fig.10 When the bend shape is a rectangular bend, within any period of the rectangular bend, the length h (i.e., the length along the circumferential direction of the ring waveguide 120) on the side close to the first doping region 121a is equal to the length (h / 2+h / 2) on the side close to the second doping region 121b. In this way, the projection areas of the first doping region 121a and the second doping region 121b in the Y-axis direction can be equal, so that when a voltage is applied to the low power control part 121, the electric field distribution is more uniform, thereby making the depletion region width in the low power control part 121 change more uniformly, thereby improving the performance of the micro-ring modulator.

[0086] In some embodiments, please refer to Figure 8 and Fig. 9The first doped region 121a includes a first lightly doped region 1211a and a first heavily doped region 1212a located on a side of the first lightly doped region 1211a close to the center of the ring waveguide 120; the second doped region 121b includes a second lightly doped region 1211b and a second heavily doped region 1212b located on a side of the second lightly doped region away from the center of the ring waveguide 120.

[0087] In some embodiments, please refer to Figure 8 and Fig. 9 The low power consumption control part 121 further includes: a first electrode 124a connected to the first heavily doped region 1212a; and a second electrode 124b connected to the second heavily doped region 1212b.

[0088] In the disclosed embodiment, since the ion concentration of the heavily doped region is high, the resistance of the heavily doped region is low. When the electrode is connected to the heavily doped region, the contact resistance can be significantly reduced, thereby improving the current transmission efficiency. In addition, a good ohmic contact can be formed between the electrode and the heavily doped region, so that the current can smoothly pass through the interface between the electrode and the heavily doped region.

[0089] In some embodiments, please refer to Fig.11 The projection of the interface between the third doping region 122a and the fourth doping region 122b in the Y-axis direction is an arc, and the arc is located on the ridge 131; the third doping region 122a includes a third lightly doped region 1221a, and a third heavily doped region 1222a located on the side of the third lightly doped region 1221a close to the center of the ring waveguide 120; the fourth doping region 122b includes a fourth lightly doped region 1221b, and a fourth heavily doped region 1222b located on the side of the fourth lightly doped region 1221b away from the center of the ring waveguide 120.

[0090] In the disclosed embodiment, since the projection of the interface between the third doping region 122a and the fourth doping region 122b in the Y-axis direction is an arc, when an RF (radio frequency) signal is applied to the high-speed modulation part 122 (i.e., the PN junction), the interface between the third doping region 122a and the fourth doping region 122b will not cause charge accumulation due to the bending angle, so that the width of the depletion region in the high-speed modulation part 122 (i.e., the PN junction) changes more uniformly, thereby increasing the performance of the micro-ring modulator. In other embodiments, the projection of the interface between the third doping region 122a and the fourth doping region 122b in the Y-axis direction may also be a bend shape, and the shape of the bend shape is similar to the bend shape in the above-mentioned embodiment. Please refer to the bend shape in the above-mentioned embodiment for understanding.

[0091] In addition, since the arc is located on the ridge 131, the depletion region of the high-speed modulation part 122 is located on the ridge 131, which is beneficial for the modulation and propagation of the optical signal in the depletion region.

[0092] In some embodiments, the high-speed modulation part 122 further includes: a third electrode 125a connected to the third heavily doped region 1222a; and a fourth electrode 125b connected to the fourth heavily doped region 1222b.

[0093] In the disclosed embodiment, since the ion concentration of the heavily doped region is high, the resistance of the heavily doped region is low. When the electrode is connected to the heavily doped region, the contact resistance can be significantly reduced, thereby improving the current transmission efficiency. In addition, a good ohmic contact can be formed between the electrode and the heavily doped region, so that the current can smoothly pass through the interface between the electrode and the heavily doped region.

[0094] In the embodiment of the present disclosure, the micro-ring modulator 100 is made of silicon-based materials. It is understandable that the low power consumption control part 121 and the high speed modulation part 122 can be formed by doping silicon; the connection area between the parts (for example, Fig.11 As shown in the A region in the figure, the ring waveguide 120 can be connected through the silicon-based ridge 131. In this way, the modulation area of ​​the ring waveguide 120 is divided into multiple parts by doping, and the parts are connected by the silicon-based ridge 131, so that the electrodes located on the heavily doped area form a series structure between the parts, and the PN junction (or PIN junction) capacitor is connected in series to reduce the total capacitance, thereby improving the bandwidth of the silicon-based micro-ring electro-optic modulator.

[0095] In addition, the present disclosure also provides a method for forming a micro-ring modulator 100. Fig.12 A schematic diagram of a process of forming a micro-ring modulator 100 provided in an embodiment of the present disclosure, Fig.13 and Fig.14 For Figure 1 The structure diagram of the micro-ring modulator 100 during the formation process is shown.

[0096] In the embodiments of the present disclosure, please refer to Fig.12 The method for forming the micro-ring modulator 100 includes: steps S110 to S130.

[0097] Step S110 , providing a semiconductor substrate 10 .

[0098] In this disclosure example, please refer to Fig.13 The semiconductor substrate 10 may be a silicon substrate, a germanium substrate, a silicon germanium substrate, a silicon-on-insulator (SOI) substrate, or a germanium on insulator (GOI) substrate.

[0099] Step S120 , etching the semiconductor substrate 10 to form a straight waveguide 110 and an initial ring waveguide 120 a located at one side of the straight waveguide 110 .

[0100] In the embodiment of the present disclosure, a dry etching process (such as a plasma etching process, a reactive ion etching process or an ion milling process) may be used to etch the Fig.13 The semiconductor substrate 10 shown is formed as Fig.14 An initial ring waveguide 120a is shown on one side of the straight waveguide 110.

[0101] Step S130 , ion doping is performed on the initial ring waveguide 120 a to form a ring waveguide 120 ; wherein the ring waveguide 120 includes a low power consumption control part 121 , a high speed modulation part 122 and a coupling waveguide part 123 .

[0102] In this disclosure example, please refer to Figure 1 The low power consumption control part 121 includes a first doping region 121a and a second doping region 121b arranged along the X-axis direction and having opposite doping types; the projection of the interface between the first doping region 121a and the second doping region 121b in the Y-axis direction is a bent shape. The high speed modulation part 122 includes a third doping region 122a and a fourth doping region 122b arranged along the X'-axis direction and having opposite doping types.

[0103] In the example disclosed herein, the doping type of the first doping region 121a may be P-type doping, and the doping type of the second doping region 121b may be N-type doping; the doping type of the third doping region 122a may be P-type doping, and the doping type of the fourth doping region 122b may be N-type doping. The P-type doping region is doped with trivalent impurity elements such as boron, gallium, and indium, and the N-type doping region is doped with pentavalent impurity elements such as phosphorus, antimony, and arsenic.

[0104] The low power consumption control part 121 formed in the embodiment of the present disclosure has a bent interface between the first doping region and the second doping region, which increases the contact area between the first doping region and the second doping region. This increases the length of the depletion region in the low power consumption control part 121 under reverse voltage and forward voltage, making the length of the optical signal modulation area (i.e., the optical path length) longer, thereby increasing the interaction of the modulated carrier distribution and improving the modulation efficiency of the optical signal.

[0105] In addition, if Fig.15 As shown in the left figure, the depletion region width of the low power control part 121 (ie, the PN junction) is shown when no voltage is applied to the low power control part 121; Fig.15 As shown in the right figure, when voltage is applied to the low power control part 121, the depletion region width of the low power control part 121 (ie, the PN junction) increases; that is, by applying voltage to the low power control part 121, the depletion region width can be changed, thereby changing the refractive index.

[0106] The high-speed modulation part 122 (i.e., PN junction) formed in the embodiment of the present disclosure causes the width of the depletion region therein to change periodically under the action of the RF (radio frequency) signal, thereby affecting the carrier distribution in the high-speed modulation part 122, and further causing the refractive index of the high-speed modulation part 122 to change periodically, thereby achieving modulation of the optical signal.

[0107] The micro-ring modulator formed in the embodiment of the present disclosure is similar to the micro-ring modulator provided in the above-mentioned embodiment. For the technical features not fully disclosed in the embodiment of the present disclosure, please refer to the above-mentioned embodiment for understanding, and no further details will be given here.

[0108] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the protection scope of the present disclosure.

[0109] It should be noted that in the present disclosure, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0110] The serial numbers of the above-mentioned embodiments of the present disclosure are only for description and do not represent the advantages or disadvantages of the embodiments.

[0111] The methods disclosed in several method embodiments provided in the present disclosure can be arbitrarily combined without conflict to obtain new method embodiments.

[0112] The features disclosed in several product embodiments provided in the present disclosure can be arbitrarily combined without conflict to obtain new product embodiments.

[0113] The features disclosed in several method or device embodiments provided in the present disclosure may be arbitrarily combined without conflict to obtain new method embodiments or device embodiments.

[0114] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A micro-ring modulator, It is characterized in that include: A straight waveguide, and a ring waveguide coupled to the straight waveguide; wherein the ring waveguide comprises: The low power consumption control part comprises a first doping region and a second doping region arranged along a first direction and having opposite doping types; the projection of the interface between the first doping region and the second doping region in the second direction is a bent shape; a high-speed modulation portion, comprising a third doping region and a fourth doping region arranged along the first direction and having opposite doping types; A coupling waveguide part connected to the low power consumption control part and the high speed modulation part and located at one side of the straight waveguide; The first direction is a direction extending outward from the center of the ring waveguide, and the second direction intersects with the plane where the micro-ring modulator is located.

2. The micro-ring modulator according to claim 1, It is characterized in that The low power consumption control part further includes: an intrinsic region; The intrinsic region is located between the first doping region and the second doping region, and a projection of the intrinsic region in the second direction is the bent shape.

3. The micro-ring modulator according to claim 1 or 2, It is characterized in that The annular waveguide is a ridge-shaped structure, which includes a ridge portion and flat plate portions located on both sides of the ridge portion along the first direction; wherein the bend is located on the ridge portion.

4. The micro-ring modulator according to claim 3, It is characterized in that A dimension of the bend in the first direction is smaller than or equal to a dimension of the ridge in the first direction.

5. The micro-ring modulator according to claim 4, It is characterized in that The bending shape at least includes a rectangular bend, a V-shaped bend, a U-shaped bend or an S-shaped bend.

6. The micro-ring modulator according to any one of claims 1 to 5, It is characterized in that The first doped region includes a first lightly doped region and a first heavily doped region located on a side of the first lightly doped region close to the center of the ring waveguide; The second doped region includes a second lightly doped region and a second heavily doped region located at a side of the second lightly doped region away from the center of the ring waveguide.

7. The micro-ring modulator according to claim 6, It is characterized in that The low power consumption control part also includes: a first electrode connected to the first heavily doped region; The second electrode is connected to the second heavily doped region.

8. The micro-ring modulator according to claim 3, It is characterized in that The projection of the interface between the third doping region and the fourth doping region in the second direction is an arc, and the arc is located on the ridge; The third doped region includes a third lightly doped region and a third heavily doped region located on a side of the third lightly doped region close to the center of the ring waveguide; The fourth doped region includes a fourth lightly doped region and a fourth heavily doped region located at a side of the fourth lightly doped region away from the center of the ring waveguide.

9. The micro-ring modulator according to claim 8, It is characterized in that The high-speed modulation part also includes: a third electrode connected to the third heavily doped region; A fourth electrode is connected to the fourth heavily doped region.

10. A method for forming a micro-ring modulator, It is characterized in that The method comprises: providing a semiconductor substrate; Etching the semiconductor substrate to form a straight waveguide and an initial ring waveguide located on one side of the straight waveguide; The initial ring waveguide is ion doped to form a ring waveguide; wherein the ring waveguide includes a low power consumption control part, a high speed modulation part and a coupling waveguide part.

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