Integrated Circuit and Method of Using the Same

Abstract

Embodiments of the present invention provide an integrated circuit and a method of using the same. The integrated circuit includes an electronic circuit. The integrated circuit further includes a photonic device. The photonic device includes a first photodetector (PD) electrically connected to the electronic circuit. The photonic device further includes a second PD electrically connected to the electronic circuit. The photonic device further includes a first waveguide configured to receive an optical signal input, wherein the first waveguide is optically connected to the first PD. The photonic device further includes a second waveguide optically connected to the second PD. The photonic device further includes a resonant structure between the first waveguide and the second waveguide, wherein the resonant structure is configured to optically couple the first waveguide to the second waveguide.

Description

Technical Field

[0001] Embodiments of the present invention relate to an integrated circuit and a method of using the same. Background Art

[0002] To transfer signals from one component to another faster than using electrical signals, photonic devices are used in integrated circuits (ICs). The electrical signal is converted into an optical signal at one end of a waveguide; the optical signal propagates along the waveguide, and the optical signal is converted back into an electrical signal at the other end of the waveguide.

[0003] However, photonic devices are made of inexpensive materials and are sensitive to process variations that affect their performance. For example, due to oxidation or moisture penetration, photonic devices are also sensitive to degradation over time. The large size of photonic devices limits further reduction of device size. Summary of the Invention

[0004] According to one aspect of an embodiment of the present invention, there is provided an integrated circuit including: an electronic circuit and a photonic device, wherein the photonic device includes: a first photodetector (PD) electrically connected to the electronic circuit; a second PD electrically connected to the electronic circuit; a first waveguide configured to receive an optical signal input, wherein the first waveguide is optically connected to the first PD; a second waveguide optically connected to the second PD; and a resonant structure located between the first waveguide and the second waveguide, wherein the resonant structure is configured to optically couple the first waveguide to the second waveguide.

[0005] According to another aspect of an embodiment of the present invention, there is provided an integrated circuit including: an electronic circuit and a photonic device, wherein the photonic device includes: a first photodetector (PD) electrically connected to the electronic circuit; a second PD electrically connected to the electronic circuit; a first waveguide configured to receive an optical signal input, wherein the first waveguide is optically connected to the first PD; a second waveguide optically connected to the second PD; a first resonant structure located between the first waveguide and the second waveguide, wherein the first resonant structure is configured to optically couple the first waveguide to the second waveguide; and a second resonant structure between the first waveguide and the second waveguide, wherein the second resonant structure is configured to optically couple the first waveguide to the second waveguide.

[0006] According to still another aspect of an embodiment of the present invention, there is provided a method of using an integrated circuit, the method including: monitoring a current between a first photodetector (PD) and an electronic circuit; determining whether the monitored current is abnormal; and in response to determining that the monitored current is abnormal, controlling a resonant structure to optically couple a first waveguide connected to the first PD to a second waveguide connected to a second PD different from the first PD. Description of the Drawings

[0007] As will be best understood from the following detailed description when read in conjunction with the accompanying drawings, various aspects of the present invention will be best understood. It should be emphasized that, in accordance with standard practice in the industry, the various components are not drawn to scale and are for illustrative purposes only. In fact, for the sake of clear discussion, the dimensions of the various components may be increased or decreased arbitrarily.

[0008] Figure 1 is a schematic diagram of a photonic device in an integrated circuit (IC) according to some embodiments.

[0009] Figure 2 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0010] Figure 3 is a graph of the optical signal power versus wavelength of a resonant structure at different temperatures according to some embodiments.

[0011] Figure 4 is a graph of the power ratio of optical signals at different ports of a photonic device versus wavelength according to some embodiments.

[0012] Figure 5 is a flowchart of a method of using a photonic device in an IC according to some embodiments.

[0013] Figure 6 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0014] Figure 7 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0015] Figure 8 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0016] Figures 9A - 9D is a cross-sectional view of a photonic device of an IC according to some embodiments.

[0017] Figure 10 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0018] Figure 11 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0019] Figure 12 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0020] Figure 13 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0021] Figure 14 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0022] Figure 15 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0023] Figure 16 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0024] Figure 17 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0025] Figure 18 is a flowchart of a method of using a photonic device in an IC according to some embodiments.

[0026] Figure 19 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0027] Figure 20 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0028] Figure 21 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0029] Figure 22 is a schematic diagram of a photonic device in an IC according to some embodiments.

[0030] Figure 23 is a block diagram of a controller used with a photonic device according to some embodiments. Detailed Description

[0031] The following disclosure provides many different embodiments or examples for implementing the features of the present invention. Specific embodiments or examples of components and arrangements are described below to simplify the present invention. Of course, these are only examples and are not intended to be limiting. For example, in the following description, forming a first component above or on a second component may include embodiments where the first and second components are in direct contact, and may also include embodiments where additional components may be formed between the first and second components such that the first and second components are not in direct contact. Additionally, the present invention may repeat reference numerals and / or letters in various examples. This repetition is for simplicity and clarity purposes and does not in itself indicate a relationship between the various embodiments and / or configurations discussed.

[0032] In addition, for ease of description, spatial relationship terms such as "below", "beneath", "lower", "above", "upper", etc. may be used herein to describe the relationship of one element or component to another element or component as shown in the figures. Except for the orientation shown in the figures, the spatial relationship terms are intended to include different orientations of the device during use or operation of the process. The device may be positioned otherwise (rotated 90 degrees or in other orientations), and the spatial relationship descriptors used herein may be interpreted accordingly.

[0033] Although photon devices in integrated circuits (ICs) help to transmit signals between components at a faster speed than electrical signals, the size of photon devices typically inhibits the formation of redundant systems that can be used in the case of partial failure of the photon device or failure of an IC component connected to the photon device. Photon devices are very sensitive to subsequent processes because the optical properties of silicon are affected by thermal variations. In cases where subsequent processes cause silicon to operate in an unsatisfactory manner, the final device is unusable, thereby reducing production yield. In addition, over time, oxidation and moisture penetration reduce the service life of some photon devices. There is no built-in redundancy in photon devices, and if a photon device deteriorates to the point of failure, the entire device will fail.

[0034] This description includes photon devices with redundant components, which helps to increase the production yield and service life of ICs including photon devices. In some embodiments, for example, thermal control or electrical control is used to actively control the redundant components. In some embodiments, the redundant components are passive, thus avoiding active control.

[0035] Compared with providing an entire redundant photon device, redundant components help to minimize the increase in device size. For example, the size of a resonant structure (such as a resonant ring) is approximately 100 square micrometers (μm 2 ). In contrast, the size of an electrical contact pad in some technology nodes is approximately 2500μm 2 . As a result, the photon device has less inhibition on further reducing the device size while increasing the production yield and service life of the device.

[0036] In addition to increasing yield and service life, the use of passive redundant elements also helps to improve the efficiency of the IC. For example, directing an optical signal to two photodetectors (PDs) can help improve the efficiency of converting an optical signal into an electrical signal. In addition, redundant components allow the power range of the receiver to be increased by distributing the optical signal over multiple PDs.

[0037] Figure 1Schematic diagram of a photonic device 100 in an IC according to some embodiments. The photonic device 100 includes a main waveguide 110 having an input port 112 and a through port 114. The photonic device 100 also includes a redundant waveguide 120 having a drop port 122 and an add port 124. A resonant structure 130 (sometimes referred to as a resonant ring) can be used to optically couple the main waveguide 110 to the redundant waveguide 120. A controller 140 is connected to a control element 142 that uses the resonant structure 130 to control the coupling. The through port 114 of the main waveguide 110 is optically connected to a first photodetector (PD) 150a. The drop port 122 of the redundant waveguide 120 is optically connected to a second PD 150b. Both the first PD 150a and the second PD 150b are configured to convert an incident optical signal into an electrical signal. Both the first PD 150a and the second PD 150b are electrically connected to an electronic circuit 160 of the IC.

[0038] The main waveguide 110 includes a core that includes an optically transparent material and is configured to allow an optical signal to propagate from the input port 112 to the through port 114. In some embodiments, the core of the main waveguide 110 includes silicon. In some embodiments, the core of the main waveguide 110 includes a polymer, glass, silicon nitride, or other suitable material. A cladding material surrounds the core. The cladding material has a different refractive index from the core to help reduce the amount of signal loss as the optical signal propagates along the main waveguide 110. In some embodiments, the cladding material is silicon oxide, a polymer, or other suitable material. In some embodiments, the cladding material is the same as the material used in an interlayer dielectric (ILD) layer or an intermetal dielectric (IMD) layer for the IC. In some embodiments, the cladding material is continuous and does not have the ILD layer or IMD layer of the IC. In some embodiments, the main waveguide 110 has a circular cross-section. In some embodiments, the main waveguide 110 has a rectangular cross-section.

[0039] The input port 112 is configured to receive an incident optical signal and couple the incident optical signal into the core of the main waveguide 110. In some embodiments, the incident optical signal is received from another component of the IC. In some embodiments, the incident optical signal is received from an external device. In some embodiments, a grating coupler is included at the input port 112 to couple the incident optical signal into the main waveguide 110. In some embodiments, an edge coupler having a lens or curvature is included at the input port 112 to increase the acceptance angle or assist in coupling the incident optical signal into the core of the main waveguide 110. In some embodiments, a coating such as an antireflection (AR) coating is located on the surface of the input port 112 to assist in coupling the incident optical signal into the core of the main waveguide 110.

[0040] The through port 114 is configured to emit an optical signal from the core of the main waveguide 110 to the first PD 150a. In some embodiments, a grating coupler is included at the through port 114 to output the optical signal to the first PD 150a. In some embodiments, an edge coupler with a lens or curvature is included at the via hole 114 to improve the coupling between the core of the main waveguide 110 and the first PD 150a and reduce crosstalk between adjacent PDs by minimizing the amount of optical signal incident on adjacent PDs. In some embodiments, a coating such as an AR coating is located on the through port 114 to maximize the intensity of the optical signal coupled to the first PD 150a.

[0041] The redundant waveguide 120 has a structure similar to that of the main waveguide 110. In some embodiments, the core of the redundant waveguide 120 includes the same material as the core of the main waveguide 110. In some embodiments, the core of the redundant waveguide 120 includes a different material from the core of the main waveguide 110. In some embodiments, the cladding of the redundant waveguide 120 has the same material as the cladding of the main waveguide 110. In some embodiments, the cladding of the redundant waveguide 120 has a different material from the cladding of the main waveguide 110. In some embodiments, the cladding of the redundant waveguide 120 is continuous with the cladding of the main waveguide 110. In some embodiments, the distance between the redundant waveguide 120 and the substrate is the same as that of the main waveguide 110. In some embodiments, the distance from the substrate to the redundant waveguide 120 is different from the distance from the substrate to the main waveguide 110.

[0042] The drop port 122 is configured to emit an optical signal from the core of the redundant waveguide 120 to the second PD 150b. In some embodiments, a grating coupler is included at the drop port 122 to output the optical signal to the second PD 150b. In some embodiments, an edge coupler with a lens or curvature is included at the drop port 122 to improve the coupling between the core of the redundant waveguide 120 and the second PD 150b and reduce crosstalk between adjacent PDs by minimizing the amount of optical signal incident on adjacent PDs. In some embodiments, a coating such as an AR coating is located on the drop port 122 to maximize the intensity of the optical signal coupled to the second PD 150b.

[0043] The add port 124 is configured not to be used during normal operation of the photonic device 100. In some embodiments, a coating such as an absorption coating is placed on the add port 124 to reduce the amount of light emitted from the add port 124 due to backscattering within the redundant waveguide 120 to help reduce the incidence of stray light on the first PD 150a or the second PD 150b. In some embodiments, the add port 124 is positioned to reduce the risk of stray light emitted from the add port 124 incident on the first PD 150a or the second PD 150b.

[0044] The resonant structure 130 is configured to selectively couple the main waveguide 110 to the redundant waveguide 120. The resonant structure 130 is positioned close to but not in contact with each of the main waveguide 110 and the redundant waveguide 120. The size of the gap between the resonant structure 130 and each of the main waveguide 110 and the redundant waveguide 120 determines the coupling efficiency between the resonant structure 130 and the corresponding waveguide. In addition to the gap, optical properties such as the refractive index also affect the coupling efficiency. Based on the arrow at the input port 112, the light coupled from the main waveguide 110 to the resonant structure 130 propagates in the counterclockwise direction. The light is enhanced due to constructive interference within the resonant structure 130. Then, the light can be coupled from the resonant structure 130 into the redundant waveguide 120 and output at the drop port 122 in the direction indicated by the arrow.

[0045] The material and cross-sectional shape of the resonant structure 130 are similar to those of the main waveguide 110. In some embodiments, the core material of the resonant structure 130 is the same as the core materials of the main waveguide 110 and the redundant waveguide 120. In some embodiments, the core material of the resonant structure 130 is different from at least one of the core materials of the main waveguide 110 and the redundant waveguide 120. In some embodiments, the cladding material of the resonant structure 130 is the same as the cladding materials of the main waveguide 110 and the redundant waveguide 120. In some embodiments, the cladding material of the resonant structure 130 is different from at least one of the cladding materials of the main waveguide 110 and the redundant waveguide 120. In some embodiments, the cladding material of the resonant structure 130 is continuous with the cladding material of at least one of the main waveguide 110 and the redundant waveguide 120.

[0046] In some embodiments, the resonant structure 130 is in the same plane as at least one of the main waveguide 110 or the redundant waveguide 120, i.e., at the same distance from the substrate. In some embodiments, the resonant structure 130 is closer to the substrate than at least one of the main waveguide 110 or the redundant waveguide 120. In some embodiments, the resonant structure is farther from the substrate than at least one of the main waveguide 110 or the redundant waveguide 120. In some embodiments, the resonant structure 130 is located between the main waveguide 110 and the redundant waveguide 120 in a direction away from the substrate. In some embodiments, in a plan view, the resonant structure 130 overlaps with at least one of the main waveguide 110 or the redundant waveguide 120. In the case where the resonant structure 130 is in a different plane from at least one of the main waveguide 110 or the redundant waveguide 120, the vertical distance is also included when determining the gap.

[0047] In some embodiments, the resonant structure 130 is an annular structure. In some embodiments, the resonant structure 130 includes a reflection grating within the resonant structure 130 to adjust the propagation direction of light within the resonant structure 130, i.e., to change the counterclockwise propagation to clockwise propagation.

[0048] In some embodiments, the cross-sectional dimensions of the resonant structure 130 are the same as those of the main waveguide 110 and the redundant waveguide 120. In some embodiments, the cross-sectional dimensions of the resonant structure 130 are different from those of the main waveguide 110 or the redundant waveguide 120.

[0049] The controller 140 is configured to actively control the coupling between the resonant structure 130 and both the main waveguide 110 and the redundant waveguide 120. To actively control the resonant structure 130 to control the coupling, the controller 140 is connected to a control element 142. The controller is configured to receive information from each of the first PD 150a and the second PD 150b to determine whether the optical signal incident on the input port 112 is being effectively converted into an electrical signal available to the electronic circuit 160 (e.g., by measuring the current between the first PD 150a and the electronic circuit 160). In response to determining that the first PD 150a is effectively converting the optical signal from the input port 112 into an electrical signal for the electronic circuit 160, the controller 140 controls the control element 142 to reduce or minimize the coupling between the resonant structure 130 and the main waveguide 110 such that the maximum amount of the optical signal incident on the input port 112 continues to the through port 114. In response to determining (e.g., by measuring the current between the first PD 150a and the electronic circuit 160) that the first PD 150a is not effectively converting the optical signal into an electrical signal for the electronic circuit 160, the controller 140 controls the control element 142 to increase or maximize the coupling between the resonant structure 130 and each of the main waveguide 110 and the redundant waveguide 120. As a result, an increased amount of the optical signal received at the input port 112 will be coupled through the resonant structure 130 to the redundant waveguide 120 and emitted through the drop port 122 to the second PD 150b.

[0050] In addition to controlling the coupling during operation, the controller 140 can also be used to tune the resonant structure 130 prior to normal operation. As described above, in some cases, the processing and optical characteristics of these components change during the process after the main waveguide 110, the redundant waveguide 120, and / or the resonant structure 130 are formed, and silicon is sensitive to the processing and optical characteristics of the changed main waveguide 110, redundant waveguide 120, and / or resonant structure 130. As a result, in some cases, the coupling between the components will be different from the initial design. The controller 140 is configured to control the control element 142 to determine the maximum and minimum coupling values by measuring the efficiency of converting the optical signal into an electrical signal (e.g., by measuring the current) through each of the first PD 150a and the second PD 150b. The parameters of the control element 142 that produce the maximum and minimum coupling values are stored for use by the controller during subsequent operation of the photonic device 100. In some embodiments, the tuning is periodically re-executed to account for changes in the performance of the photonic device 100 over time.

[0051] The control element 142 is controlled by the controller 140 to adjust the coupling between the resonant structure 130 and each of the main waveguide 110 and the redundant waveguide 120. In some embodiments, the control element 142 is a thermal element, such as a resistor. In some embodiments, the control element 142 is an electric field generating element, such as an inductor. The thermal control of the resonant structure 130 affects the optical properties of the resonant structure 130, such as the refractive index. The electric field control of the resonant structure 130 affects the optical properties, such as the refractive index. The photonic device 100 includes a single control element 142. However, in some embodiments, additional control elements are included. In some embodiments, at least one control element 142 is positioned to affect each of the main waveguide 110, the redundant waveguide 120, and / or the resonant structure 130.

[0052] The first PD 150a is configured to receive an optical signal emitted from the through port 114. The first PD 150a is configured to convert the received optical signal into an electrical signal and transmit the electrical signal to the electronic circuit 160. In some embodiments, the first PD 150a includes a photodiode. In some embodiments, the first PD 150a includes an isolation structure to reduce crosstalk between the first PD 150a and adjacent PDs.

[0053] The second PD 150b is configured to receive an optical signal emitted from the drop port 122. The second PD 150b is configured to convert the received optical signal into an electrical signal and transmit the electrical signal to the electronic circuit 160. In some embodiments, the second PD 150b includes a photodiode. In some embodiments, the second PD 150b includes an isolation structure to reduce crosstalk between the second PD 150b and adjacent PDs. In some embodiments, the second PD 150b abuts the first PD 150a. In some embodiments, the second PD 150b is spaced apart from the first PD 150a. In some embodiments, the second PD 150b is adjacent to the first PD 150a. In some embodiments, another PD is located between the second PD 150b and the first PD 150a.

[0054] The electronic circuit 160 is configured to receive electrical signals from the first PD 150a and the second PD 150b. The electronic circuit 160 is configured to use the electrical signals to perform functions for implementing the design functions of the IC. In some embodiments, the electronic circuit 160 includes a memory, a logic circuit, or other suitable components.

[0055] The above description is directed to a photonic device 100 that receives an optical signal and transfers the optical signal to an electronic circuit 160 via a first PD 150a and / or a second PD 150b. One of ordinary skill in the art will recognize that the functionality of the photonic device 100 can also receive an optical signal at a drop port 122 or a through port 114 and emit the signal from an input port 112. In such a configuration, the first PD 150a and the second PD 150b can be replaced with optical emission elements that receive an electrical signal from the electronic circuit 160; convert the electrical signal into an optical signal; and emit the optical signal to the drop port 122 or the through port 114. The resonant structure 130 then selectively couples the redundant waveguide 120 to the main waveguide 110 based on a signal from the controller 140 to emit the optical signal from the input port 112 to another component in an external device or an IC. One of ordinary skill in the art will understand this configuration based on the above description of the functionality of the photonic device 100, and thus additional drawings and descriptions of this configuration are omitted for the sake of brevity. One of ordinary skill in the art will recognize that similar modifications are possible for the other drawings described below. For example, a multiplexer (MUX) can be configured as a demultiplexer (DEMUX) that reverses the propagation direction of the optical signal within the MUX.

[0056] Figure 2 is a schematic diagram of a photonic device 200 in an IC according to some embodiments. The photonic device 200 is similar to the photonic device 100. Compared with the photonic device 100, the photonic device 200 includes a second resonant structure 132. The second resonant structure 132 is similar to the resonant structure 130. In some embodiments, the material, size, and / or shape of the second resonant structure 132 are the same as those of the resonant structure 130. In some embodiments, the second resonant structure 132 is different from the resonant structure 130 in at least one of the material, size, and / or shape. In some embodiments, the cladding of the second resonant structure 132 is continuous with the cladding of the resonant structure 130.

[0057] The inclusion of the second resonant structure 132 in the photonic device 200 results in a rearrangement of the redundant waveguide 120 ( Figure 1 ) to obtain an arrangement of the redundant waveguide 120'. The optical signal coupled from the main waveguide 110 to the redundant waveguide 120' via the resonant structure 130 and the second resonant structure 132 will propagate through the redundant waveguide 120' in a direction opposite to the direction in the redundant waveguide 120 ( Figure 1 ). That is, the optical signal will pass through the resonant structure 130 counterclockwise, as in the photonic device 100, and then pass through the resonant structure 132 clockwise before being coupled to the redundant waveguide 120'.

[0058] The photonic device 200 includes a single control element 142. In some embodiments, the photonic device 200 includes multiple control elements to separately control the resonant structure 130 and the second resonant structure 132. Similar to the coupling between the resonant structure 130 and the main waveguide 110 and the redundant waveguide 120 described with respect to the photonic device 100 ( Figure 1 ), the coupling between the resonant structure 130 and the second resonant structure 132 is controlled based on the optical properties and spacing between these components.

[0059] Figure 3 FIG. 300 is a graph of the optical signal power versus wavelength of the resonant structure at different temperatures according to some embodiments. As described above, the coupling efficiency between the resonant structure (e.g., the resonant structure 130 ( Figure 1 )) and the waveguide (e.g., the main waveguide 110 ( Figure 1 )) can be controlled using a thermal control element that controls the temperature of the resonant structure. FIG. 300 includes multi-peak coupling for each temperature of the resonant structure. The wavelength of the optical signal is indicated by the design wavelength 310 in FIG. 300. When the resonant structure is at a temperature of 20° C., a coupling peak is achieved at the design wavelength 310.

[0060] As a result, during operation, if coupling between the resonant structure and the waveguide is desired, the temperature of the resonant structure will be controlled at 20° C. Conversely, if coupling is to be avoided, the temperature of the resonant structure should be controlled below 20° C. Taking the photonic device 100 as an example, the controller 140 will drive the control element 142 to set the temperature of the resonant structure 130 to 20° C. to output an optical signal at the drop port 122, and will drive the control element 142 to set the temperature of the resonant structure 130 to a temperature different from 20° C. to output an optical signal at the through port 114. The determination of the coupling peak and the associated temperature can be determined by the controller (e.g., the controller 140 ( Figure 1 )) using the tuning process described above.

[0061] Figure 4 FIG. 400 is a graph of the power ratio of the optical signal at different ports of the photonic device versus wavelength according to some embodiments. FIG. 400 indicates that the output power at the through port is inversely proportional to the output power at the drop port. That is, when the output power at the through port is at a maximum, the output power at the drop port is at a minimum. The output power is related to the coupling of the resonant structure (e.g., the resonant structure 130 ( Figure 1 )) and the waveguide (e.g., the main waveguide 110 and / or the redundant waveguide 120). When the resonant structure is coupled to the two waveguides, then the optical signal is transmitted to the drop port. When the resonant structure is not coupled to the two waveguides, the optical signal remains in the main waveguide and propagates to the through port.

[0062] From the perspective of the output power ratio at the design wavelength of 310, the output power at the drop port is the maximum value, and the output power at the through port is the minimum power. Using the graph 300( Figure 3 ) and the photonic device 100( Figure 1 ) as an example, the controller 140 drives the control element 142 to make the temperature of the resonant structure 20 °C. As a result, the optical signal from the input port 112 is coupled to the redundant waveguide 120 through the resonant structure 130 and output at the drop port 122. This example generates the output power ratio of the graph 400 at the design wavelength of 310. Those of ordinary skill in the art will recognize that other design wavelengths are possible. Those of ordinary skill in the art will further recognize that the above tuning and control are applicable to many photonic devices, and for the sake of brevity, the detailed discussion on how to achieve tuning and control will not be repeated hereinafter.

[0063] Figure 5 is a flowchart of a method 500 for using a photonic device in an IC according to some embodiments. The method 500 can be used to tune and operate the photonic device 100( Figure 1 ), the photonic device 200( Figure 2 ) or other photonic devices including redundant waveguides.

[0064] In operation 505, light is emitted into the main waveguide, such as the main waveguide 110( Figure 1 ). In some embodiments, the light is emitted from a component of the IC including the photonic device. In some embodiments, the light is emitted from an external device. In some embodiments, the light includes a single wavelength. In some embodiments, the light includes multiple wavelengths.

[0065] In operation 510, the current between each PD of the photonic device and the electronic circuit is monitored. In some embodiments, an ammeter is used to monitor the current. In some embodiments, the current information is provided to the controller of the photonic device, such as the controller 140( Figure 1 ). In some embodiments, operation 510 is continuously performed throughout the method 500 to provide feedback on the state of the photonic device.

[0066] In operation 515, the main waveguide is coupled to at least one redundant waveguide using at least one resonant structure. In some embodiments, the controller (such as the controller 140( Figure 1 )) drives at least one control element (such as the control element 142( Figure 1 )) to couple the main waveguide to at least one redundant waveguide. In some embodiments, the control element is a thermal control element. In some embodiments, the control element is a voltage control element. In some embodiments, the main waveguide is passively coupled to at least one redundant waveguide through at least one resonator structure.

[0067] In operation 520, the control element is scanned over a range of values to tune at least one resonator structure. The current between each PD and the electronic circuit is measured during operation 520 to determine the path taken by the optical signal for each value of the control element. In some embodiments, a controller (e.g., controller 140( Figure 1 )) electrically controls the control element (e.g., control element 142( Figure 1 )) to set the control element to various different values. In some embodiments, the controller drives the control element to change the temperature of at least one resonator structure. In some embodiments, the controller drives the control element to change the electric field applied to at least one resonator structure. In some embodiments that include multiple resonator structures, multiple control elements are scanned to determine the path of the optical signal for different combinations of values of the control elements.

[0068] In operation 525, the control settings that produce the peak current for each PD are determined. Based on the data collected during operation 520, it is determined which settings produce the maximum current between each PD and the electronic circuit. For example, as shown in graph 300( Figure 3 ), different temperature values produce different peaks. Identifying the value that produces the maximum coupling at the design wavelength (e.g., 20 °C( Figure 3 )) helps the photon device to accurately switch between the main waveguide and the redundant waveguide during operation of the photon device. In some embodiments that include multiple resonator structures, multiple control values are identified as producing the peaks for different PDs.

[0069] In operation 530, the control settings are stored in a memory. In some embodiments, the time at which the control settings are stored is also stored in the memory. In some embodiments, after a predetermined period of time, operations 510 - 530 are repeated to characterize any changes in the performance of the photon device, such as due to oxidation or moisture penetration. Updating the control settings to characterize the changes in the photon device helps ensure that the photon device continues to operate at maximum performance throughout the lifespan of the photon device.

[0070] In operation 535, the photon device is operated using the main waveguide. The main waveguide (e.g., main waveguide 110( Figure 1 )) receives an optical signal at an input port (e.g., input port 112( Figure 1 )) and transmits the incident light through a through port (e.g., through port 114( Figure 1 )) to a first PD (e.g., first PD 150a( Figure 1 ). The first PD receives the optical signal and converts it into an electrical signal, which is then transmitted to an electronic circuit (e.g., electronic circuit 160( Figure 1 ). For example, during operation 535, the current of the electrical signal between the first PD and the electronic circuit is monitored using operation 510.

[0071] In operation 540, it is determined whether an abnormal current is detected at the first PD. The abnormal current indicates that the signal communication from an input port, such as the input port 112 of a main waveguide (e.g., main waveguide 110( Figure 1 ))), to an electronic circuit (e.g., electronic circuit 160( Figure 1 )) includes a defect. In response to the current between the first PD (e.g., first PD 150a( Figure 1 )) and the electronic circuit being different from an expected value, the abnormal current is identified. The expected value is based on the intensity of the transmitted light to be received by the input port of the main waveguide. In some embodiments, the current value obtained during the most recent iteration of operation 520 is used as the expected value. In some embodiments, a tolerance threshold is applied to the expected value to help characterize minor variations and defects in the photonic device. For example, if the main waveguide is damaged and light leaks from the main waveguide, the optical signal reaching the first PD will be reduced. As a result, the current between the first PD and the electronic circuit will be lower than expected. In another example, if current leaks from another PD adjacent to the first PD into the electronic circuit, the current between the first PD and the electronic circuit will be higher than expected. In both cases, the electrical signal received by the electronic circuit is not an accurate representation of the information the electronic circuit is to use. In some embodiments, this determination is made by a controller (e.g., controller 140( Figure 1 ))). Figure 1 ))

[0072] In response to determining that no abnormal current is detected, method 500 returns to operation 535 and continues normal operation.

[0073] In response to determining that an abnormal current is detected, method 500 proceeds to operation 545, where the main waveguide is coupled to at least one redundant waveguide using at least one resonant structure. Using the control settings stored in operation 530, the photonic device can accurately and precisely couple the optical signal into at least one redundant waveguide, such as redundant waveguide 120( Figure 1 ). Once the optical signal is coupled into at least one redundant waveguide, the electronic circuit (e.g., electronic circuit 160( Figure 1 )) will begin to receive an electrical signal from a PD (e.g., second PD 150b( Figure 1 )) optically connected to at least one redundant waveguide.

[0074] One of ordinary skill in the art will recognize that method 500 can be used to operate photonic devices including photonic device 100( Figure 1 ), photonic device 200( Figure 2and many photon devices including other photon devices with some of the photon devices described below. In some embodiments, the order of operations in method 500 is changed. For example, in some embodiments, operation 510 is performed after operation 515. In some embodiments, additional operations are included in method 500. For example, in some embodiments, operations 510-530 are periodically repeated to describe drift in the photon device. In some embodiments, at least one operation of method 500 is omitted. For example, in some embodiments, operation 515 is omitted or combined with operation 520.

[0075] In some embodiments, method 500 is used to split an optical signal between two PDs (e.g., a first PD 150a and a second PD 150b( Figure 1 )) to increase the total power that can be received by an electronic circuit (e.g., electronic circuit 160( Figure 1 )) while minimizing degradation.

[0076] Figure 6 is a schematic diagram of a photon device 600 in an IC according to some embodiments. The photon device 600 is similar to the photon device 200( Figure 2 ). The electronic circuit 160( Figure 2 ) is not included as part of Figure 6 , but those of ordinary skill in the art will recognize that the PDs of the photon device 600 are connected to the electronic circuit. Compared with the photon device 200( Figure 2 ), the photon device includes a second redundant waveguide 610, a third resonant structure 630, a fourth resonant structure 632, a second controller 640, a second control element 642, and a third PD 150c.

[0077] The second redundant waveguide 610 is located on the side of the main waveguide 110 opposite to the redundant waveguide 120'. The second redundant waveguide 610 includes an add port 612 and a drop port 614. The drop port is optically connected to the third PD 150c. In some embodiments, the second redundant waveguide 610 and the redundant waveguide 120' are located on the same side of the main waveguide 110.

[0078] The third resonant structure 630 and the fourth resonant structure 632 are independently similar to the resonant structure 130. In some embodiments, the materials, dimensions, and / or shapes of the third resonant structure 630 and the fourth resonant structure 632 are the same as those of the resonant structure 130. In some embodiments, at least one of the third resonant structure 630 or the fourth resonant structure 632 is different from the resonant structure 130 in at least one of the material, dimension, and / or shape. In some embodiments, the claddings of the third resonant structure 630 and the fourth resonant structure 632 are continuous with the cladding of the resonant structure 130. In some embodiments, the fourth resonant structure 632 is omitted. In some embodiments where the fourth resonant structure 632 is omitted, the second redundant waveguide 610 is arranged in a manner similar to the redundant waveguide 120( Figure 1 ) to describe the propagation direction of the optical signal. In some embodiments, the fourth resonant structure 642 and the second resonant structure 132 are omitted, and the redundant waveguide 120' and the second redundant waveguide 610 are adjusted accordingly. Although the photonic device 600 includes two resonant structures on each side of the main waveguide 110, those of ordinary skill in the art will recognize that arrangements with different numbers of resonant structures on each side of the main waveguide 110 are possible. For example, in some embodiments, one resonant structure is located on the first side of the main waveguide 110 and three resonant structures are located on the second side of the main waveguide 110.

[0079] The second controller 640 is similar to the controller 140. In some embodiments, the second controller and the controller 140 are combined into a single controller. In some embodiments, the single controller will maintain the ability to independently drive the control element 142 and the second control element 642.

[0080] The second control element 642 is similar to the control element 142. In some embodiments, the second control element 642 includes a first type of control element, and the control element 142 includes a second type of control element different from the first type. For example, in some embodiments, the control element 142 is a thermal control element and the second control element 642 is an electrical control element. In some embodiments, the control element 142 and the second control element 642 are of the same type of control element. For example, in some embodiments, both the control element 142 and the second control element 642 are thermal control elements. In some embodiments, the control element 142 and the second control element 642 are integrated into a single control element.

[0081] The third PD 150c is configured to receive an optical signal from the drop port 614. The third PD 150c is configured to convert the optical signal into an electrical signal and transmit the electrical signal to an electronic circuit, such as the electronic circuit 160( Figure 2)。In some embodiments, the third PD 150c is the same PD as the first PD 150a and the second PD 150b. In some embodiments, the third PD 150c is different from at least one of the first PD 150a or the second PD 150b.

[0082] Figure 7 is a schematic diagram of a photonic device 700 in an IC according to some embodiments. The photonic device 700 has a Mach-Zehnder interferometer (MZI) arrangement 710. The MZI arrangement 710 includes an input port 712 configured to receive an optical signal. A first beam splitter 720 is configured to split the optical signal between a first arm 722a and a second arm 722b. A controller 740 is configured to drive a first control element 742a to control the propagation of the split optical signal along the first arm 722a, and to drive a second control element 742b to control the propagation of the split optical signal along the second arm 722b. A second beam splitter 750 is configured to split each of the split optical signal along the first arm 722a and the split optical signal along the second arm 722b. A first through port 714a is configured to transmit the optical signal from the second beam splitter 750 to the first PD 150a. A second through port 714b is configured to transmit the optical signal from the second beam splitter 750 to the second PD 150b. Does not include the electronic circuit 160( Figure 2 ) as Figure 7 part of, but one of ordinary skill in the art will recognize that the PDs of the photonic device 700 are connected to the electronic circuit.

[0083] The input port 712 is similar to the input port 112( Figure 1 ). The first through port 714a and the second through port 714b are similar to the through ports 114( Figure 1 ). The controller 740 is similar to the controller 140( Figure 1 ). Compared with the controller 140, the controller 740 is configured to independently drive the first control element 742a and the second control element 742b. Each of the first arm 722a and the second arm 722b is similar to the main waveguide 110( Figure 1 ). In some embodiments, each of the first control element 742a and the second control element 742b is similar to the control element 142( Figure 1 ). In some embodiments, at least one of the first control element 742a or the second control element 742b includes a PIN phase shifter.

[0084] The first beam splitter 720 is configured to split an input optical signal into a first portion propagating along a first arm 722a and a second portion propagating along a second arm 722b. In some embodiments, the first beam splitter 720 is a 50-50 beam splitter, meaning that half of the optical signal received by the first beam splitter 720 is transmitted to each of the first arm 722a and the second arm 722b.

[0085] The second beam splitter 750 is configured to combine and split the optical signals from each of the first arm 722a and the second arm 722b to a first drop port 714a and a second drop port 714b. In some embodiments, the second beam splitter 750 is a 50-50 beam splitter. In some embodiments, the second beam splitter 750 includes a beam combining element and a beam splitting element. That is, in some embodiments, the optical signals from each of the first arm 722 and the second arm 722b are combined and then split into two optical paths. One of the optical paths is along the first drop port 714a and the other optical path is along the second drop port 714b.

[0086] Compared with the photonic device 100( Figure 1 ), selectively directing the optical signal to the first PD 150a or the second PD 150b is achieved by phase controlling the optical signals propagating along each of the first arm 722a and the second arm 722b. The first control element 742a is configured to slow down the propagation rate of the optical signal along the arm 722a. Slowing down the propagation rate changes the phase of the wave of the optical signal reaching the second splitter 750 from the first arm 722a. The change in phase results in destructive interference with the optical signal from the second arm 722b, which reduces the intensity of the optical signal along one of the first drop port 714a or the second drop port 714b. The second control element 742b operates similarly along the second arm 722b. By controlling the first control element 742a and the second control element 742b, the controller can adjust the amount of light along each of the first drop port 714a and the second drop port 714b by adjusting the interference pattern at the second beam splitter 750.

[0087] Figure 8 is a schematic diagram of a photonic device 800 in an IC according to some embodiments. The photonic device 800 is similar to the photonic device 700( Figure 7 ). Compared with the photonic device 700( Figure 7 ), the photonic device includes a second MZI 710' connected to the second drop port 714b of the MZI 710. The third drop port 714a' leaving the second MZI 710' is optically connected to the second PD 150b. The fourth drop port 714b' leaving the second MZI 710' is optically connected to the third PD 150c. Does not include the electronic circuit 160( Figure 2 ) as Figure 8portion, but one of ordinary skill in the art will recognize that the PDs of the photonic device 800 are connected to the electronic circuit.

[0088] The second MZI 710' is similar to the MZI 710. In some embodiments, the second MZI 710' includes control elements of the same type as the MZI 710. In some embodiments, the second MZI 710' includes control elements of a different type than the MZI 710. By connecting the second MZI 710' in series with the MZI 710, the number of PDs to which an optical signal can be directed is increased compared to a photonic device with fewer PDs, thus providing greater flexibility for the photonic device 800.

[0089] Figures 9A to 9D is a cross-sectional view of a photonic device for an IC according to some embodiments. Figure 9A is according to some embodiments along Figure 7 a cross-sectional view of the photonic device 900A taken along line A-A. One of ordinary skill in the art will recognize that although the photonic device 900A is along Figure 7 line A-A, the structure of the photonic device 900A can be used for other photonic devices, such as the photonic device 100 ( Figure 1 ), the photonic device 200 ( Figure 2 ), the photonic device 600 ( Figure 6 ), the photonic device 800 ( Figure 8 ) or other photonic devices.

[0090] The photonic device 900A includes a substrate 902 and a dielectric layer 904 above the substrate 902. A waveguide 910a extends through the dielectric layer 904. A contact 920 is located above the dielectric layer 904 and is electrically connected to a heater 940 through an interconnect structure 930. The heater 940 and the interconnect structure 930 are located in the dielectric layer 904. The heater 940 is close enough to the waveguide 910 so as to be able to change the temperature of the waveguide 910 in order to adjust the optical characteristics and / or the dimensions of the waveguide 910 based on the thermal expansion coefficient of the waveguide 910.

[0091] The substrate 902 includes a silicon substrate. The dielectric layer 904 provides electrical isolation between the components of the IC and serves as a cladding for the waveguide 910a. One of ordinary skill in the art will understand that the dielectric layer 904 extending across the substrate 902 will also surround the first arm 722a of the photonic device ( Figure 7 ). Thus, the cladding around the first arm 722a and the second arm 722b is continuous. As described in the present invention, a similar continuous cladding arrangement is also possible in other photonic devices. In some embodiments, the dielectric layer 904 includes silicon oxide. The waveguide 910a is the photonic device 700 ( Figure 7) the second arm 722b. In some embodiments, the waveguide 910 is a different waveguide in different photonic devices or resonant structures (such as the resonant structure 130( Figure 1 ) or other resonant structures). The contact 920 is an electrical contact for providing an electrical connection between the heater 940 and other components (such as the controller 140, Figure 1 ). The interconnect structure 930 is a combination of conductive wires and conductive vias for electrically connecting the contact 920 and the heater 940. In some embodiments, the contact 940 is part of the interconnect structure 930. The heater 940 is configured to receive an electrical signal and convert the electrical signal into a heat output. In some embodiments, the heater includes a resistive heating element. The heater 940 is configured to be used as the second control element 742b( Figure 7 ) of the photonic device 700.

[0092] Figure 9B is a cross-sectional view of the photonic device 900B taken along line A-A according to some embodiments. Those of ordinary skill in the art will recognize that although the photonic device 900B is along Figure 7 line A-A, the structure of the photonic device 900B can be used for other photonic devices, such as the photonic device 100( Figure 7 ), the photonic device 200( Figure 1 ), the photonic device 600( Figure 2 ), the photonic device 800( Figure 6 ), or other photonic devices. For simplicity of drawing, Figure 8 the substrate 902 and the dielectric layer 904 are not labeled in Figure 9B .

[0093] Compared with the photonic device 900A( Figure 9A ), the photonic device 900B includes a waveguide 910b, two contacts 920a and 920b, two interconnect structures 930a and 930b, two highly doped regions 935a and 935b, and two doped regions 950a and 950b. The waveguide 910b is similar to the waveguide 910a( Figure 9A ). The two contacts 920a and 920b are similar to the contact 920( Figure 9A ). The two interconnect structures 930a and 930b are similar to the interconnect structure 930( Figure 9A ).

[0094] The two highly doped regions 935a and 935b have the same dopant type. In some embodiments, the dopant type is p-type. In some embodiments, the dopant type is n-type. The highly doped region 935a is electrically connected to the contact 920a through the interconnect structure 930a. The highly doped region 935b is electrically connected to the contact 920b through the interconnect structure 930b.

[0095] The two doped regions 950a and 950b have the same dopant type. In some embodiments, the dopant type is p-type. In some embodiments, the dopant type is n-type. The two doped regions 950a and 950b have the same dopant type as the two highly doped regions 935a and 935b. The doping concentration of each of the two doped regions 950a and 950b is lower than the doping concentration of each of the two highly doped regions 935a and 935b. The doped region 950a extends from the highly doped region 935a towards the waveguide 910b. In some embodiments, the doped region 950a is in direct contact with the waveguide 910b. In some embodiments, the doped region 950a is separated from the waveguide 910b. The doped region 950b extends from the highly doped region 935b towards the waveguide 910b. In some embodiments, the doped region 950b is in direct contact with the waveguide 910b. In some embodiments, the doped region 950b is separated from the waveguide 910b. The highly doped regions 935a and 935b and the doped regions 950a and 950b are configured to be used as the second control element 742b of the photonic device 700( Figure 7 ).

[0096] Figure 9C is a cross-sectional view of the photonic device 900C taken along line A-A according to some embodiments. Those of ordinary skill in the art will recognize that although the photonic device 900C is along Figure 7 line A-A, the structure of the photonic device 900C can be used for other photonic devices, such as the photonic device 100( Figure 7 ), the photonic device 200( Figure 1 ), the photonic device 600( Figure 2 ), the photonic device 800( Figure 6 ) or other photonic devices. To simplify the drawing, Figure 8 the substrate 902 and the dielectric layer 904 are not labeled in Figure 9C .

[0097] Compared with the photonic device 900B( Figure 9B ), the photonic device 900C includes a waveguide 910c, two highly doped regions 935c and 935d, and doped regions 960a and 960b. The waveguide 910c is similar to the waveguide 910a( Figure 9A ). The two contacts 920a and 920b are similar to the contact 920( Figure 9A ). The two interconnect structures 930a and 930b are similar to the interconnect structure 930( Figure 9A ).

[0098] The two highly doped regions 935c and 935d have opposite dopant types. The highly doped region 935c is electrically connected to the contact 920a through the interconnect structure 930a. The highly doped region 935d is electrically connected to the contact 920b through the interconnect structure 930b.

[0099] The two doped regions 960a and 960b have opposite dopant types. The doped region 960a has the same dopant type as the highly doped region 935c. In some embodiments, the dopant type is p-type. In some embodiments, the dopant type is n-type. The doped region 960b has the same dopant type as the highly doped region 935d. In some embodiments, the dopant type is p-type. In some embodiments, the dopant type is n-type. The doping concentration of each of the two doped regions 960a and 960b is lower than the doping concentration of each of the two highly doped regions 935c and 935d. The doped region 960a extends from the highly doped region 935c to the waveguide 910c. In some embodiments, the doped region 960a directly contacts the waveguide 910c. In some embodiments, the doped region 960a is separated from the waveguide 910c. The doped region 960b extends from the highly doped region 935d to the waveguide 910c. In some embodiments, the doped region 960b directly contacts the waveguide 910c. In some embodiments, the doped region 960b is separated from the waveguide 910c. The highly doped regions 935c and 935d and the doped regions 960a and 960b are configured to be used as the second control element 742b of the photonic device 700( Figure 7 ).

[0100] Figure 9D is a cross-sectional view of the photonic device 900D taken along line B-B according to some embodiments. Those of ordinary skill in the art will recognize that although the photonic device 900D is along Figure 7 line B-B, the structure of the photonic device 900D can be used for other photonic devices, such as the photonic device 100( Figure 7 ), the photonic device 200( Figure 1 ), the photonic device 600( Figure 2 ), the photonic device 800( Figure 6 ), or other photonic devices. To simplify the drawing, Figure 8 the substrate 902 and the dielectric layer 904 are not labeled in Figure 9D .

[0101] is the same as the photonic device 900C( Figure 9C)In contrast, the photonic device 900D includes an electrical connection to the second PD 150b instead of a control element for the waveguide. In some embodiments, the second PD 150b is a germanium-based PD. Although the photonic device 900D is associated with the second PD 150b, one of ordinary skill in the art will recognize that the photonic device 900D is also applicable to the first PD 150a, the third PD 150c, and other PD structures.

[0102] The doped region 960a provides an electrical connection between the second PD 150b and the contact 920a through the highly doped region 935c and the interconnect structure 130a. The doped region 960b provides an electrical connection between the second PD 150b and the contact 920b through the highly doped region 935d and the interconnect structure 130b. Electrical connection to the electronic circuit 160( Figure 1 )is possible.

[0103] Figure 10 is a schematic diagram of a photonic device 1000 in an IC according to some embodiments. The photonic device 1000 functions as a 2x1 multiplexer (MUX). The photonic device 1000 includes a first input waveguide 1010a configured to receive light of a first wavelength. The photonic device 1000 further includes a second input waveguide 1010b configured to receive light of a second wavelength different from the first wavelength. The photonic device 1000 further includes an output waveguide 1020 configured to output an optical signal including both light of the first wavelength and light of the second wavelength. The first resonant structure 1030a is configured to optically couple the first input waveguide 1010a to the output waveguide 1020. The first redundant resonant structure 1030a' is configured to optically couple the first input waveguide 1010a to the output waveguide 1020. The second resonant structure 1030b is configured to optically couple the second input waveguide 1010b to the output waveguide 1020. The second redundant resonant structure 1030b' is configured to optically couple the second input waveguide 1010b to the output waveguide 1020. The controller 1040 is configured to control the coupling between the first input waveguide 1010a and the output waveguide 1020 through the first redundant resonant structure 1030a'. The controller 1040 is further configured to control the coupling between the second input waveguide 1010b and the output waveguide 1020 through the second redundant resonant structure 1030b'. The first monitoring structure 1050a is configured to monitor the amount of light remaining in the first input waveguide 1010a after being coupled by the first resonant structure 1030a and the first redundant resonant structure 1030a'. The second monitoring structure 1050b is configured to monitor the amount of light remaining in the second input waveguide 1010b after being coupled by the second resonant structure 1030b and the second redundant resonant structure 1030b'.

[0104] The first input waveguide 1010a includes a first input port 1012a and a first through port 1014a. The second input waveguide 1010b includes a second input port 1012b and a second through port 1014b. Each of the first input port 1012a and the second input port 1012b is similar to the input port 112( Figure 1 ). Each of the first through port 1014a and the second through port 1014b is similar to the through port 114( Figure 1 ).

[0105] The output waveguide 1020 includes a drop port 1022 and an add port 1024. The drop port 1022 is similar to the drop port 122( Figure 1 ). The add port 1024 is similar to the add port 124( Figure 1 ). One of ordinary skill in the art will recognize that the PD will be located at the output of the drop port 1022.

[0106] Each of the first resonant structure 1030a, the first redundant resonant structure 1030a', the second resonant structure 1030b, and the second redundant resonant structure 1030b' is similar to the resonant structure 130( Figure 1 ). By including redundant resonant structures (such as the first redundant resonant structure 1030a' and the second redundant resonant structure 1030b'), the photonic device 1000 can continue to operate even if one of the resonant structures fails.

[0107] The controller 1040 is similar to the controller 140( Figure 1 ). To simplify the drawing, although Figure 10 does not include control elements, one of ordinary skill in the art will recognize that the photonic device 1000 includes at least one control element to control the coupling through the first redundant resonant structure 1030a' and the second redundant resonant structure 1030b'. In some embodiments, a single controller 1040 controls all the control elements in the photonic device 1000. In some embodiments, the control elements are controlled by separate controllers 1040.

[0108] Each of the first monitoring structure 1050a and the second monitoring structure 1050b is capable of receiving light and converting the light into an electrical signal. In some embodiments, the first monitoring structure 1050a and the second monitoring structure 1050b are PDs. In some embodiments, the first monitoring structure 1050a and the second monitoring structure 1050b include grating couplers, doped silicon regions, or other suitable structures capable of converting an optical signal into an electrical signal. One of ordinary skill in the art will recognize that, for example, through an electronic circuit (such as the electronic circuit 160( Figure 1The electronic feedback of ()) is used to notify the controller 1040 of a fault in the light to be coupled out from either the first input waveguide 1010a or the second input waveguide 1010b. Based on this feedback, the controller 1040 can drive one or more control elements to couple the first input waveguide 1010a to the output waveguide 1020 through the first redundant resonant structure 1030a', or couple the second input waveguide 1010b to the output waveguide 1020 through the second redundant resonant structure 1030b'. The active control device provides a redundant resonant structure for maintaining the operation of the photonic device 1000 even when one of the resonant structures fails. Those of ordinary skill in the art will recognize that in some embodiments, the controller 1040 also drives at least one control element to assist in tuning the coupling using the first resonant structure 1030a and / or the second resonant structure 1030b.

[0109] Figure 11 is a schematic diagram of a photonic device 1100 in an IC according to some embodiments. The photonic device 1100 is similar to the photonic device 1000 ( Figure 10 ). Compared with the photonic device 1000 ( Figure 10 ), the photonic device 1100 includes a plurality of resonant rings in each of the first resonant structure 1130a, the first redundant resonant structure 1130a', the second resonant structure 1130b, and the second redundant resonant structure 1130b'. Compared with the photonic device 1000 ( Figure 10 ), the output waveguide 1020 is oriented in a different direction to illustrate the change in the propagation direction of the optical signal due to the inclusion of additional resonant rings. Those of ordinary skill in the art will recognize that in some embodiments, additional resonant rings can be included in the photonic device 1100. Although the photonic device 1100 includes two resonant structures at each location, those of ordinary skill in the art will recognize that arrangements with different numbers of resonant structures at each location are possible. For example, in some embodiments, one resonant structure is located at the first redundant resonant structure 1130a', and two resonant structures are located at the second redundant resonant structure 1130b'.

[0110] Figure 12 is a schematic diagram of a photonic device 1200 in an IC according to some embodiments. The photonic device 1200 is similar to the photonic device 1000 ( Figure 10 ). Compared with the photonic device 1000 ( Figure 10 ), the photonic device 1200 includes beam splitters 1205 and 1207 to divide the input port into two arms. As a result, the photonic device 1200 can operate as a 2x2 MUX.

[0111] The photonic device 1200 includes a first input port 1202 configured to receive light of a first wavelength. The photonic device 1200 further includes a second input port 1204 configured to receive light of a second wavelength different from the first wavelength. The optical signal at the first input port 1202 is split by a first beam splitter 1205 so that the split optical signal propagates along a first arm 1210a and a second arm 1210b. The optical signal at the second input port 1204 is split by a second beam splitter 1207 so that the split optical signal propagates along a third arm 1210c and a fourth arm 1210d. The photonic device 1200 further includes a first output waveguide 1220a and a second output waveguide 1220b configured to output an optical signal including both the first wavelength and the second wavelength of light. A first resonant structure 1230a is configured to optically couple the first arm 1210a to the first output waveguide 1220a. A first redundant resonant structure 1230a' is configured to optically couple the first arm 1210a to the first output waveguide 1220a. A second resonant structure 1230b is configured to optically couple the second arm 1210b to the second output waveguide 1220b. A second redundant resonant structure 1230b' is configured to optically couple the second arm 1210b to the second output waveguide 1220b. A third resonant structure 1230c is configured to optically couple the third arm 1210c to the second output waveguide 1220b. A third redundant resonant structure 1230c' is configured to optically couple the third arm 1210c to the second output waveguide 1220b. A fourth resonant structure 1230d is configured to optically couple the fourth arm 1210d to the first output waveguide 1220a. A fourth redundant resonant structure 1230d' is configured to optically couple the fourth arm 1210d to the first output waveguide 1220a.

[0112] A first monitoring structure 1250a is configured to monitor the amount of light remaining in the first arm 1210a after being coupled by the first resonant structure 1230a and the first redundant resonant structure 1230a'. A second monitoring structure 1250b is configured to monitor the amount of light remaining in the second arm 1210b after being coupled by the second resonant structure 1230b and the second redundant resonant structure 1230b'. A third monitoring structure 1250c is configured to monitor the amount of light remaining in the third arm 1210c after being coupled by the third resonant structure 1230c and the third redundant resonant structure 1230c'. A fourth monitoring structure 1250d is configured to monitor the amount of light remaining in the fourth arm 1210d after being coupled by the fourth resonant structure 1230d and the fourth redundant resonant structure 1230d'.

[0113] For simplicity of drawing, Figure 12 a controller is not included. However, the photonic device 1200 includes a component similar to the controller 1040 ( Figure 10) The controller is used to selectively couple the arms of the photonic device 1200 to the corresponding output waveguides using respective redundant resonant structures.

[0114] Each of the first input port 1202 and the second input port 1204 is similar to the input port 112 ( Figure 1 ). The first arm 1210a includes a first through port 1214a. The second arm 1210b includes a second through port 1214b. The third arm 1210c includes a third through port 1214c. The fourth arm 1210d includes a fourth through port 1214d. The first through port 1214a, the second through port 1214b, the third through port 1214c, and the fourth through port 1214d are similar to the through port 114 ( Figure 1 ). One of ordinary skill in the art will recognize that the PDs will be located at the outputs of the drop ports 1222a and 1222b.

[0115] The first output waveguide 1220a includes a first drop port 1222a and a first add port 1224a. The second output waveguide 1220b includes a second drop port 1222b and a second add port 1224b. Each of the first drop port 1222a and the second drop port 1222b is similar to the drop port 122 ( Figure 1 ). Each of the first add port 1224a and the second add port 1224b is similar to the add port 124 ( Figure 1 ).

[0116] Each of the first resonant structure 1230a, the first redundant resonant structure 1230a', the second resonant structure 1230b, the second redundant resonant structure 1230b', the third resonant structure 1230c, the third redundant resonant structure 1230c', the fourth resonant structure 1230d, and the fourth redundant resonant structure 1230d' is similar to the resonant structure 130 ( Figure 1 ). By including redundant resonant structures, such as the first redundant resonant structure 1230a', the second redundant resonant structure 1230b', the third redundant resonant structure 1230c', and the fourth redundant resonant structure 1230d', the photonic device 1200 can continue to operate even if one of the resonant structures fails.

[0117] To simplify the drawing, although Figure 12It does not include a control element, but those of ordinary skill in the art should recognize that the photonic device 1200 includes at least one control element for controlling the coupling through the first redundant resonant structure 1230a', the second redundant resonant structure 1203b', the third redundant resonant structure 1230c', and the fourth redundant resonant structure 1230d'. In some embodiments, a single controller controls all the control elements in the photonic device 1200. In some embodiments, the control elements are controlled by separate controllers.

[0118] The first monitoring structure 1250a, the second monitoring structure 1250b, the third monitoring structure 1250c, and the fourth monitoring structure 1250d are respectively similar to the first monitoring structure 1050a. Based on the output from the monitoring structures, the controller can use the photonic device 1200 so as to operate the photonic device 1200 in a manner similar to that described above with respect to the photonic device 1000 ( Figure 10 )

[0119] Figure 13 is a schematic diagram of a photonic device 1300 in an IC according to some embodiments. The photonic device 1300 is similar to the photonic device 1200 ( Figure 12 ). Compared with the photonic device 1200 ( Figure 12 ), the photonic device 1300 includes multiple resonant rings for each of the first resonant structure 1330a, the first redundant resonant structure 1330a', the second resonant structure 1330b, the second redundant resonant structure 1330b', the third resonant structure 1330c, the third redundant resonant structure 1330c', the fourth resonant structure 1330d, and the fourth redundant resonant structure 1330d'. Compared with the photonic device 1200 ( Figure 12 ), the first output waveguide 1220a and the second output waveguide 1220b are oriented in different directions to describe the change in the propagation direction of the optical signal due to the inclusion of additional resonant rings. Those of ordinary skill in the art will recognize that, in some embodiments, additional resonant rings can be included in the photonic device 1300. Although the photonic device 1300 includes two resonant structures at each location, those of ordinary skill in the art will recognize that arrangements with different numbers of resonant structures at each location are possible. For example, in some embodiments, one resonant structure is located at the first redundant resonant structure 1330a', and two resonant structures are located at the second redundant resonant structure 1330b'.

[0120] Figure 14Schematic diagram of a photonic device 1400 in an IC according to some embodiments. The photonic device 1400 is capable of operating as a demultiplexer DeMUX. The photonic device 1400 includes an input waveguide 1410 having an input port 1412 and a through port 1414. The through port 1414 is in optical communication with a monitoring device 1460. A first output waveguide 1420a is configured to be optically coupled to the input waveguide 1410 through a first resonant structure 1430a. A second output waveguide 1420b is configured to be optically coupled to the input waveguide 1410 through a second resonant structure 1430b. A redundant output waveguide 1420c is configured to be optically coupled to the input waveguide 1410 through a redundant resonant structure 1430c. For simplicity of drawing, although not labeled, each of the first output waveguide 1420a, the second output waveguide 1420b, and the redundant output waveguide 1420c includes an add port and a drop port. The drop port of the first output waveguide 1420a is optically coupled to a first PD 1450a. The drop port of the second output waveguide 1420b is optically coupled to a second PD 1450b. The drop port of the redundant waveguide 1420c is optically coupled to a redundant PD 1450c.

[0121] To be used as a demultiplexer, the photonic device 1400 is configured to receive light of multiple wavelengths in the input waveguide 1410. A first wavelength is coupled to the first output waveguide 1420a and output to the first PD 1450a. A second wavelength is coupled to the second output waveguide 1420b and output to the second PD 1450b. During operation, the redundant resonant structure 1430c is tunable to couple the first wavelength or the second wavelength to the redundant output waveguide 1420c and output to the redundant PD 1450c. In some embodiments, a control structure such as a controller 140 and a control element 142( Figure 1 ) is used to tune the redundant resonant structure 1430c. For clarity, Figure 14 the control structure is not shown in

[0122] By including redundant resonant structures 1430c, redundant output waveguides 1420c, and redundant PDs 1450c, the photonic device 1400 is able to continue operating as expected even if one of the structures associated with the first output waveguide 1420a or the second output waveguide 1420b is damaged or becomes inoperative. In some embodiments, even when the structures associated with the first output waveguide 1420a and the second output waveguide 1420b are operating properly, the redundant resonant structure 1430c is configured to couple the first wavelength or the second wavelength into the redundant output waveguide 1420c in order to maximize the amount of optical signal captured by the PDs of the photonic device 1400. In this way, any wavelength of the optical signal that is not coupled out of the input waveguide 1410 by the first resonant structure 1430a or the second resonant structure 1430b has a second chance to be coupled out of the input waveguide 1410 by the redundant resonant structure 1430c. Although Figure 14 two wavelengths are included, those of ordinary skill in the art will recognize that additional wavelengths may be considered for the photonic device 1400.

[0123] Each of the input waveguide 1410, the first output waveguide 1420a, the second output waveguide 1420b, and the redundant output waveguide 1420c is similar to the input waveguide 110( Figure 1 ). Each of the first resonant structure 1430a, the second resonant structure 1430b, and the redundant resonant structure 1430c is similar to the resonant structure 130( Figure 1 ). Each of the first PD 1450a, the second PD 1450b, and the redundant PD 1450c is similar to the first PD 150( Figure 1 ). The monitoring device 1460 is similar to the first monitoring structure 1250a( Figure 12 ).

[0124] Figure 15 is a schematic diagram of a photonic device 1500 in an IC according to some embodiments. The photonic device 1500 is similar to the photonic device 1400( Figure 14 ). Compared with the photonic device 1400( Figure 14 ), the photonic device 1500 includes multiple resonant rings in each of the first resonant structure 1530a, the second resonant structure 1530b, and the redundant resonant structure 1530c. Compared with the photonic device 1400( Figure 14)In contrast, the first output waveguide 1520a, the second output waveguide 1520b, and the redundant output waveguide 1520c are oriented in different directions to describe the change in the optical signal propagation direction due to the inclusion of the additional resonant ring. Those of ordinary skill in the art will recognize that, in some embodiments, the additional resonant ring can be included in the photonic device 1500. Although the photonic device 1500 includes two resonant structures at the location, those of ordinary skill in the art will recognize that arrangements with different numbers of resonant structures at each location are possible. For example, in some embodiments, one resonant structure is located at the first redundant resonant structure 1530a', and two resonant structures are located at the second redundant resonant structure 1530b'.

[0125] Figure 16 is a schematic diagram of a photonic device 1600 in an IC according to some embodiments. The photonic device 1600 can operate as a demultiplexer. The photonic device 1600 includes an input waveguide 1610 having an input port 1612 and a through port 1614. The through port 1614 is in optical communication with a monitoring device 1660. The first output waveguide 1620a is configured to be optically coupled to the input waveguide 1610 through the first resonant structure 1630a. The first redundant output waveguide 1620a' is configured to be optically coupled to the input waveguide 1610 through the first redundant resonant structure 1630a'. The second output waveguide 1620b is configured to be optically coupled to the input waveguide 1610 through the second resonant structure 1630b. The second redundant output waveguide 1620b' is configured to be optically coupled to the input waveguide 1610 through the second redundant resonant structure 1630b'. Although not labeled for clarity of the drawing, each of the first output waveguide 1620a, the first redundant output waveguide 1620a', the second output waveguide 1620b, and the second redundant output waveguide 1620b' includes an add port and a drop port. The drop ports of the first output waveguide 1620a and the first redundant output waveguide 1620a are both optically coupled to the first PD 1650a. The drop ports of the second output waveguide 1620b and the second redundant output waveguide 1620b' are both optically coupled to the second PD 1650b.

[0126] To be used as a demultiplexer, the photonic device 1600 is configured to receive light of multiple wavelengths in the input waveguide 1610. The first wavelength is coupled to the first output waveguide 1620a and output to the first PD 1650a. The second waveguide is coupled to the second output waveguide 1620b and output to the second PD 1650b. During operation, the first redundant resonant structure 1630a' is tunable to couple the first wavelength to the first redundant output waveguide 1620a' and output to the first PD 1650a. During operation, the second redundant resonant structure 1630b' is tunable to couple the second wavelength to the second redundant output waveguide 1620b' and output to the second PD 1650b. In some embodiments, a control structure such as the controller 140 and the control element 142( Figure 1 ) is used to tune at least one of the first redundant resonant structure 1630a' or the second redundant resonant structure 1630b'. For clarity, the control structure is not shown in the figure.

[0127] By including the first redundant resonant structure 1620a' and the second redundant resonant structure 1620b', the photonic device 1600 is able to continue operating as expected even if one of the structures associated with the first output waveguide 1620a or the second output waveguide 1620b is damaged or becomes inoperative. In some embodiments, even when the structures associated with the first output waveguide 1620a and the second output waveguide 1620b are operating properly, at least one of the first redundant resonant structure 1630a' or the second redundant resonant structure 1630b' is configured to couple the first wavelength or the second wavelength into the corresponding redundant output waveguide 1620a' or 1620b' in order to maximize the amount of optical signal captured by the PDs of the photonic device 1600. In this way, any wavelength of the optical signal that is not coupled out of the input waveguide 1610 by the first resonant structure 1630a or the second resonant structure 1630b has a second chance to be coupled out of the input waveguide 1610 to improve the overall coupling efficiency. Although Figure 16 only two wavelengths are included, those of ordinary skill in the art will recognize that the photonic device 1600 can contemplate additional wavelengths.

[0128] Each of the input waveguide 1610, the first output waveguide 1620a, the first redundant output waveguide 1620a', the second output waveguide 1620b, and the second redundant output waveguide 1620b' is similar to the input waveguide 110( Figure 1 ). Each of the first resonant structure 1630a, the first redundant resonant structure 1630a', the second resonant structure 1630b, and the second redundant resonant structure 1630b' is similar to the resonant structure 130( Figure 1 ). Each of the first PD 1650a and the second PD 1650b is similar to the first PD 150( Figure 1)。The monitoring device 1660 is similar to the first monitoring structure 1250a( Figure 12 )。

[0129] Figure 17 is a schematic diagram of a photonic device 1700 in an IC according to some embodiments. The photonic device 1700 is similar to the photonic device 1600( Figure 16 )。Compared with the photonic device 1600( Figure 16 ), the photonic device 1700 includes multiple resonant rings in each of a first resonant structure 1730a, a first redundant resonant structure 1730a', a second resonant structure 1730b, and a second redundant resonant structure 1730b'. Compared with the photonic device 1600( Figure 16 ), the first resonant structure 1730a, the first redundant resonant structure 1730a', the second resonant structure 1730b, and the second redundant resonant structure 1730b' are oriented in different directions to describe the change in the propagation direction of the optical signal due to the inclusion of additional resonant rings. Those of ordinary skill in the art will recognize that, in some embodiments, additional resonant rings can be included in the photonic device 1700. Although the photonic device 1700 includes two resonant structures at the location, those of ordinary skill in the art will recognize that arrangements with different numbers of resonant structures at each location are possible. For example, in some embodiments, one resonant structure is located at the first redundant resonant structure 1730a', and two resonant structures are located at the second redundant resonant structure 1730b'.

[0130] Figure 18 is a flowchart of a method 1800 for using a photonic device in an IC according to some embodiments. The method 1800 can be used to tune and operate the photonic device 1400( Figure 14 ), the photonic device 1500( Figure 15 ), the photonic device 1600( Figure 16 ), the photonic device 1700( Figure 17 ), or other photonic devices including redundant waveguides.

[0131] In operation 1805, light of a selected wavelength is emitted into an input waveguide, such as the input waveguide 1410( Figure 14 ). In some embodiments, the light is emitted from an IC component including the photonic device. In some embodiments, the light is emitted from an external device.

[0132] In operation 1810, the current between each PD and the electronic circuit of the photonic device is monitored. In some embodiments, an ammeter is used to monitor the current. In some embodiments, the current information is provided to a controller of the photonic device, such as the controller 140( Figure 1 ). In some embodiments, operation 1810 is continuously performed throughout the method 1800 to provide feedback on the state of the photonic device.

[0133] In operation 1815, an input waveguide is coupled to an output waveguide by scanning a control signal of at least one resonant structure. In some embodiments, a controller (e.g., controller 140( Figure 1 )) drives at least one control element (e.g., control element 142( Figure 1 )) to couple the input waveguide to at least one output waveguide. In some embodiments, the control element is a thermal control element. In some embodiments, the control element is a voltage control element. In some embodiments, the input waveguide is passively coupled to at least one output waveguide through at least one resonator structure.

[0134] In operation 1820, the control element is scanned over a range of values to tune at least one redundant resonator structure. The current between each PD and the electronic circuitry is measured during operation 1820 to determine the path taken by the optical signal for each value of the control element. In some embodiments, a controller (e.g., controller 140( Figure 1 )) electrically controls the control element (e.g., control element 142( Figure 1 )) to set the control element to various different values. In some embodiments, the controller drives the control element to change the temperature of at least one redundant resonator structure. In some embodiments, the controller drives the control element to change the electric field applied to at least one redundant resonator structure. In some embodiments that include multiple resonator structures, multiple control elements are scanned to determine the path of the optical signal for different combinations of values of the control elements.

[0135] Once the control settings that produce the peak current for each PD are determined, the control settings of the resonator structure and the redundant resonator structure are stored. In some embodiments, the time at which the control settings are stored is also stored in a memory. In some embodiments, after a predetermined period of time, operations 1805 - 1820 are repeated to account for any changes in the performance of the photonic device, such as due to oxidation or moisture penetration. Updating the control settings to account for changes in the photonic device helps ensure that the photonic device continues to operate at maximum performance throughout the lifespan of the photonic device.

[0136] In operation 1825, it is determined whether all of the wavelengths for which the photonic device is designed to receive have been tuned. In response to determining that fewer wavelengths than all wavelengths have been tuned, method 1800 proceeds to operation 1830. In response to determining that all wavelengths have been tuned, method 1800 advances to operation 1835.

[0137] In operation 1830, the next wavelength of the designed wavelength of the photonic device is selected, and method 1800 returns to operation 1805.

[0138] In operation 1835, the photonic device is operated using the initial settings. The input waveguide receives light at multiple wavelengths, and each wavelength to be separated is coupled to a corresponding output waveguide respectively. In some embodiments, at least one control element is used to maintain at least one resonant structure in a coupled mode during the initial settings. In some embodiments, the coupling between the input waveguide and the output waveguide is all through passive coupling. In some embodiments, redundant resonant structures are controlled to be in a coupled state. In some embodiments, at least one redundant resonant structure is not controlled to be in a coupled state.

[0139] In operation 1840, it is determined whether an abnormal current is detected at any PD of the photonic device. The abnormal current indicates that the communication of light at the corresponding wavelength to the electronic circuit includes a defect. In response to the current between a PD (e.g., the first PD 1450a( Figure 14 )) and the electronic circuit being different from the expected value, the abnormal current is identified. The expected value is based on the intensity of the emitted light to be received by the input port of the input waveguide. In some embodiments, the current value obtained during the most recent iteration of operation 1820 is used as the expected value. In some embodiments, a tolerance threshold is applied to the expected value to help describe minor variations and defects in the photonic device. For example, if any resonant structure is damaged and light leaks from the input waveguide or fails to couple, the corresponding wavelength reaching the PD will decrease. As a result, the current between the PD and the electronic circuit will be lower than expected. In another example, if current leaks from another PD into the electronic circuit, the current between the PD and the electronic circuit will be higher than expected. In both cases, the electrical signal received by the electronic circuit is not an accurate representation of the information that the electronic circuit is to use. In some embodiments, this determination is made by a controller (e.g., the controller 140( Figure 1 ))).

[0140] In response to determining that no abnormal current is detected, method 1800 returns to operation 1835 and continues normal operation.

[0141] In response to determining that an abnormal current is detected, method 1800 enters operation 1845, where the input waveguide is coupled to at least one redundant waveguide using at least one redundant resonant structure. Using the control settings determined in operations 1815 and 1820, the photonic device can accurately and precisely couple the optical signal into at least one redundant waveguide, such as the redundant waveguide 1420c( Figure 14 ). Once the optical signal is coupled into at least one redundant waveguide, the electronic circuit (e.g., the electronic circuit 160( Figure 1 )) will start receiving an electrical signal from the PD (e.g., the redundant PD 1450c( Figure 14 )) that is optically connected to at least one redundant waveguide.

[0142] Those of ordinary skill in the art will recognize that method 1800 can be used to operate many photonic devices including photonic device 1400( Figure 14 ), photonic device 1500( Figure 15 ), photonic device 1600( Figure 16 ), photonic device 1700( Figure 17 ) and other photonic devices including some of the photonic devices described below. In some embodiments, the order of operations in method 1800 is changed. For example, in some embodiments, operation 1810 is performed after operation 1815. In some embodiments, additional operations are included in method 1800. For example, in some embodiments, operations 1805 - 1820 are periodically repeated to account for drift in the photonic device. In some embodiments, at least one operation of method 1800 is omitted. For example, in some embodiments, operation 1815 is omitted or combined with operation 1820.

[0143] Although method 1800 for demultiplexing operations has been described, those of ordinary skill in the art will understand how to modify method 1800 to be applicable to, for example, the MUX structures in photonic device 1000( Figure 10 ), photonic device 1100( Figure 11 ), photonic device 1200( Figure 12 ), photonic device 1300( Figure 13 ) or additional photonic devices.

[0144] Figure 19 is a schematic diagram of photonic device 1900 in an IC according to some embodiments. Photonic device 1900 is similar to photonic device 1600( Figure 16 ). Compared with photonic device 1600( Figure 16 ), photonic device 1900 includes a two - stage resonant structure. The first two - stage resonant structure 1930a is configured to optically couple the input waveguide 1610 to the first output waveguide 1620a. The first redundant two - stage resonant structure 1930a' is configured to optically couple the input waveguide 1610 to the first redundant output waveguide 1620a'. The second two - stage resonant structure 1930b is configured to optically couple the input waveguide 1610 to the second output waveguide 1620b. The second redundant two - stage resonant structure 1930b' is configured to optically couple the input waveguide 1610 to the second redundant output waveguide 1620b'. Each of the two - stage resonant structures has a similar arrangement. For the sake of brevity, only the first two - stage resonant structure 1930a is discussed in detail.

[0145] The first two - stage resonant structure 1930a is configured to achieve a similar function as the resonant structure 1630a( Figure 16 ). In contrast, by including a two - stage resonant structure, crosstalk is reduced. That is, compared with using the first resonant structure 1630a(Figure 16 ) As compared, light other than the first wavelength reaching the first output waveguide 1620a is less likely when using the first two - stage resonant structure 1930a. However, the size of the first two - stage resonant structure 1930a is larger than that of the first resonant structure 1630a( Figure 16 ).

[0146] The first two - stage resonant structure 1930a includes a first resonant ring 1935 configured to optically couple the first wavelength from the input waveguide 1610 to the intermediate waveguide 1970. A second resonant ring 1937 is configured to couple the first wavelength from the intermediate waveguide 1970 to the first output waveguide 1620a. The monitoring structure 1960 is optically coupled to the drop port of the intermediate waveguide 1970. By including multiple couplings between the input waveguide 1610 and the first output waveguide 1620a, the risk of light with non - first wavelength reaching the first output waveguide 1620a is reduced compared to other resonant structures.

[0147] The intermediate waveguide 1970 is similar to the input waveguide 1610. Each of the first resonant ring 1935 and the second resonant ring 1937 is similar to the first resonant structure 1630a( Figure 16 ). The monitoring device 1960 is similar to the monitoring device 1660.

[0148] Although the photonic device 1900 includes two - stage resonant structures at each coupling position, those of ordinary skill in the art will recognize that a combination of two - stage resonant structures and single - stage resonant structures is possible. For example, in some embodiments, the photonic device includes a first two - stage resonant structure 1930a and a first redundant resonant structure 1630a' for coupling the first wavelength between the input waveguide 1610 and the first PD 1650a( Figure 16 ). By replacing the first redundant two - stage resonant structure 1930a' with the first redundant resonant structure 1630a', when using redundant components, the total size of the photonic device 1900 is reduced, but the risk of crosstalk increases.

[0149] Figure 20 is a schematic diagram of a photonic device 2000 in an IC according to some embodiments. The photonic device 2000 is similar to the photonic device 1900( Figure 19 ). Compared with the photonic device 1900( Figure 19 ), the photonic device 2000 includes multiple resonant rings coupled to each of a first two - stage resonant structure 2030a, a first redundant two - stage resonant structure 2030a', a second two - stage resonant structure 2030b, and a second redundant two - stage resonant structure 2030b'. Compared with the photonic device 1900( Figure 19)In contrast, the first two-stage resonant structure 2030a, the first redundant two-stage resonant structure 2030a', the second two-stage resonant structure 2030b, and the second redundant two-stage resonant structure 2030b' face different directions to describe the change in the optical signal propagation direction due to the inclusion of additional resonant rings. Those of ordinary skill in the art will recognize that, in some embodiments, the additional resonant rings can be included in the photonic device 2000. Although the photonic device 2000 includes two resonant structures at a position, those of ordinary skill in the art will recognize that arrangements with different numbers of resonant structures at each position are possible. Each of the two-stage resonant structures has a similar arrangement. For the sake of brevity, only the first two-stage resonant structure 2030a is discussed in detail.

[0150] The first two-stage resonant structure 2030a includes a first resonant ring 2035 configured to optically couple a first wavelength from the input waveguide 1610 to the intermediate waveguide 2070. A second resonant ring 2037 is configured to couple the first wavelength from the intermediate waveguide 2070 to the first output waveguide 1620a. The monitoring structure 2060 is optically coupled to the drop port of the intermediate waveguide 2070. By including multi-coupling between the input waveguide 1610 and the first output waveguide 1620a, the risk of light other than the first wavelength reaching the first output waveguide 1620a is reduced compared to other resonant structures.

[0151] The intermediate waveguide 2070 is similar to the input waveguide 1610. Each of the first resonant ring 2035 and the second resonant ring 2037 is similar to the first resonant structure 1730a( Figure 17 ). The monitoring device 2060 is similar to the monitoring device 1660.

[0152] Figure 21 is a schematic diagram of a photonic device 2100 in an IC according to some embodiments. The photonic device 2100 is similar to the photonic device 1000( Figure 10 ). Compared with the photonic device 1000( Figure 10 ), the photonic device 2100 includes two-stage resonant structures. The first two-stage resonant structure 1930a is configured to optically couple the first input waveguide 1010a to the output waveguide 1020. The first redundant two-stage resonant structure 1930a' is configured to optically couple the first input waveguide 1010a to the output waveguide 1020. The second two-stage resonant structure 1930b is configured to optically couple the second input waveguide 1010b to the output waveguide 1020. The second redundant two-stage resonant structure 1930b' is configured to optically couple the second input waveguide 1010b to the output waveguide 1020.

[0153] Although the photonic device 2100 includes a two-stage resonant structure at each coupling location, one of ordinary skill in the art will recognize that a combination of a two-stage resonant structure and a single-stage resonant structure is possible. For example, in some embodiments, the photonic device includes a first two-stage resonant structure 1930a and a first redundant resonant structure 1030a' ([ Figure 10 ) that couple a first wavelength between a first input waveguide 1010a and an output waveguide 1020. By replacing the first redundant two-stage resonant structure 1930a' with the first redundant resonant structure 1030a', when redundant components are used, the overall size of the photonic device 2100 is reduced, but the risk of crosstalk increases.

[0154] Figure 22 is a schematic diagram of a photonic device 2200 in an IC according to some embodiments. The photonic device 2200 is similar to the photonic device 2100 ([ Figure 21 ). Compared with the photonic device 2100 ([ Figure 21 ), the photonic device 2200 includes a plurality of resonant rings coupled to each of a first two-stage resonant structure 2030a, a first redundant two-stage resonant structure 2030a', a second two-stage resonant structure 2030b, and a second redundant two-stage resonant structure 2030b'. One of ordinary skill in the art will recognize that, in some embodiments, additional resonant rings can be included in the photonic device 2200. Although the photonic device 2200 includes two resonant structures at the location, one of ordinary skill in the art will recognize that an arrangement with a different number of resonant structures at each location is possible.

[0155] Figure 23 is a block diagram of a controller 2300 for use with a photonic device according to some embodiments. The controller 2300 includes a hardware processor 2302 and a non-transitory computer-readable storage medium 2304, which is encoded (i.e., stores) with computer program code 2306 (i.e., a set of executable instructions). The computer-readable storage medium 2304 is also encoded with instructions 2307 to interface with a control element (such as control element 142 ([ Figure 1 ). The processor 2302 is electrically coupled to the computer-readable storage medium 2304 via a bus 2308. The processor 2302 is also electrically coupled to an I / O interface 2310 via the bus 2308. A network interface 2312 is also electrically connected to the processor 2302 via the bus 2308. The network interface 2312 is connected to a network 2314 such that the processor 2302 and the computer-readable storage medium 2304 can be connected to external elements via the network 2314. The processor 2302 is configured to execute the computer program code 2306 encoded in the computer-readable storage medium 2304 so that the controller 2300 can be used to perform some or all of the operations described in method 500, method 1800, or any of the functional descriptions of the photonic device above.

[0156] In some embodiments, the processor 2302 is a central processing unit (CPU), a multiprocessor, a distributed processing system, an application specific integrated circuit (ASIC), and / or a suitable processing unit.

[0157] In some embodiments, the computer-readable storage medium 2304 is an electronic, magnetic, optical, electromagnetic, infrared, and / or semiconductor system (or apparatus or device). For example, the computer-readable storage medium 2304 includes semiconductor or solid state memories, magnetic tapes, removable computer floppy disks, random access memory (RAM), read-only memory (ROM), hard disks, and / or optical disks. In some embodiments using optical disks, the computer-readable storage medium 2304 includes compact disk read-only memory (CD-ROM), compact disk read / write (CD-R / W), and / or digital video disk (DVD).

[0158] In some embodiments, the storage medium 2304 stores computer program code 2306 configured to cause the controller 2300 to execute method 500, method 1800, or any of the functions described above with respect to the photonic device. In some embodiments, the storage medium 2304 also stores information required to execute method 500, method 1800, or any of the functions described above with respect to the photonic device, as well as information generated during the execution of method 500, method 1800, or any of the functions described above with respect to the photonic device, such as current measurement parameters 2316, wavelength parameters 2318, elapsed time parameters 2320, control element setting parameters 2322, and / or a set of executable instructions to perform the operations of method 500, method 1800, or any of the functions described above with respect to the photonic device. The current measurement parameters 2316 relate to the current measured between the PD and the electronic circuit. The wavelength parameters 2318 relate to the wavelength of the light to be coupled. In some embodiments, the wavelength parameters 2318 relate to light of multiple wavelengths. The elapsed time parameters 2320 relate to the amount of time elapsed since the previous tuning of the control element in the photonic device. The control element setting parameters 2322 relate to the voltage applied to each control element to selectively initiate coupling within the photonic device.

[0159] In some embodiments, the storage medium 2304 stores instructions 2307 for interfacing with the control element. The instructions 2307 enable the processor 2302 to generate signals readable by the control element to effectively implement method 500, method 1800, or any of the functions described above with respect to the photonic device.

[0160] The controller 2300 includes an I / O interface 2310. The I / O interface 2310 is coupled to an external circuit. In some embodiments, the I / O interface 2310 includes a keyboard, keypad, mouse, trackball, trackpad, and / or cursor direction keys for communicating information and commands to the processor 2302.

[0161] The controller 2300 also includes a network interface 2312 coupled to the processor 2302. The network interface 2312 allows the controller 2300 to communicate with a network 2314 that connects to one or more other computer systems. The network interface 2314 includes a wireless network interface, such as Bluetooth, WIFI, WIMAX, GPRS, or WCDMA; or a wired network interface, such as Ethernet, USB, or IEEE-1394. In some embodiments, the method 500, the method 1800, or any of the functions described above with respect to the photonic device are implemented in two or more controllers 2300, and information such as current measurements, wavelengths, elapsed time, and control element settings are exchanged between different controllers 2300 via the network 2314.

[0162] One aspect of this description relates to an integrated circuit. The integrated circuit includes an electronic circuit. The integrated circuit also includes a photonic device. The photonic device includes a first photodetector (PD) electrically connected to the electronic circuit. The photonic device also includes a second PD electrically connected to the electronic circuit. The photonic device also includes a first waveguide configured to receive an optical signal input, wherein the first waveguide is optically connected to the first PD. The photonic device also includes a second waveguide optically connected to the second PD. The photonic device also includes a resonant structure between the first waveguide and the second waveguide, wherein the resonant structure is configured to optically couple the first waveguide to the second waveguide. In some embodiments, the photonic device also includes a controller, wherein the controller is configured to tune the resonant structure to selectively optically couple the first waveguide to the second waveguide. In some embodiments, the controller is configured to tune the resonant structure by applying an electric field to the resonant structure. In some embodiments, the controller is configured to tune the resonant structure by controlling a control element for heating the resonant structure. In some embodiments, the controller is configured to tune the resonant structure based on a measured current between the first PD and the electronic circuit. In some embodiments, the resonant structure includes a plurality of resonant rings. In some embodiments, the resonant structure includes a single resonant ring. In some embodiments, the resonant structure includes a two-stage resonant structure. In some embodiments, the photonic device includes a multiplexer. In some embodiments, the photonic device includes a demultiplexer. In some embodiments, the photonic device includes a Mach-Zehnder interferometer (MZI). In some embodiments, the photonic device also includes a third PD electrically connected to the electronic circuit; a third waveguide optically connected to the third PD; and a second resonant structure between the first waveguide and the third waveguide, wherein the second resonant structure is configured to optically couple the first waveguide to the third waveguide. In some embodiments, the resonant structure has the same structure as the second resonant structure. In some embodiments, the resonant structure has a different structure from the second resonant structure.

[0163] One aspect of the present description relates to an integrated circuit. The integrated circuit includes an electronic circuit. The integrated circuit further includes a photonic device. The photonic device includes a first photodetector (PD) electrically connected to the electronic circuit. The photonic device further includes a second PD electrically connected to the electronic circuit. The photonic device further includes a first waveguide configured to receive an optical signal input, wherein the first waveguide is optically connected to the first PD. The photonic device further includes a second waveguide optically connected to the second PD. The photonic device further includes a first resonant structure between the first waveguide and the second waveguide, wherein the first resonant structure is configured to optically couple the first waveguide to the second waveguide. The photonic device further includes a second resonant structure between the first waveguide and the second waveguide, wherein the second resonant structure is configured to optically couple the first waveguide to the second waveguide. In some embodiments, the integrated circuit further includes a controller, wherein the controller is configured to tune the second resonant structure to selectively couple the first waveguide to the second waveguide. In some embodiments, the controller is configured to tune the second resonant structure based on a current between the first PD and the electronic circuit. In some embodiments, the second resonant structure is configured to optically couple the first waveguide to the second waveguide during the entire operation of the photonic device. In some embodiments, the photonic device includes a multiplexer or a demultiplexer.

[0164] One aspect of the present specification relates to a method of using an integrated circuit. The method includes monitoring a current between a first photodetector (PD) and an electronic circuit. The method further includes determining whether the monitored current is abnormal. The method further includes, in response to determining that the monitored current is abnormal, controlling a resonant structure to optically couple a first waveguide connected to the first PD to a second waveguide connected to a second PD different from the first PD.

[0165] The foregoing outlines the features of several embodiments so that those skilled in the art may better understand the various aspects of the present disclosure. Those skilled in the art should understand that they can readily use the present disclosure as a basis for designing or modifying other processes and structures for achieving the same purposes and / or achieving the same advantages as those introduced herein. Those skilled in the art should also recognize that such equivalent structures do not depart from the spirit and scope of the present invention, and that they may make various changes, substitutions, and alterations in the present invention without departing from the spirit and scope of the present invention.

Claims

1. An integrated circuit, comprising: An electronic circuit; And A photonic device, wherein the photonic device comprises: A first photodetector electrically connected to the electronic circuit; A second photodetector electrically connected to the electronic circuit through a contact; A first waveguide configured to receive an optical signal input, wherein the first waveguide is optically connected to the first photodetector; A second waveguide optically connected to the second photodetector; A third waveguide optically connected to the second photodetector; A first resonant structure located between the first waveguide and the second waveguide, wherein the first resonant structure is configured to optically couple the first waveguide to the second waveguide; A first redundant resonant structure located between the first waveguide and the third waveguide, wherein the first redundant resonant structure is configured to optically couple the first waveguide to the third waveguide; A controller comprising control elements, wherein the controller is configured to tune the first resonant structure and the first redundant resonant structure; A highly doped region located on both sides of the second photodetector; A doped region extending from the highly doped region towards the second photodetector, wherein the sidewalls and the bottom surface of the second photodetector are in contact with the doped region, Wherein the doped region provides an electrical connection between the second photodetector and the contact through the highly doped region and an interconnect structure located above the highly doped region.

2. The integrated circuit according to claim 1, wherein, The photonic device further comprises: heaters located above each of the first waveguide and the second waveguide; An interconnect structure located above the heaters; A contact located above the interconnect structure and electrically connected to the heaters through the interconnect structure.

3. The integrated circuit according to claim 1, wherein, The controller is configured to tune the first resonant structure by applying an electric field to the first resonant structure.

4. The integrated circuit according to claim 1, wherein, The controller is configured to tune the first resonant structure by controlling the control elements for heating the first resonant structure.

5. The integrated circuit according to claim 1, wherein The controller is configured to tune the first resonant structure based on a measured current between the first photodetector and the electronic circuit.

6. The integrated circuit according to claim 1, wherein, The first resonant structure comprises a plurality of resonant rings.

7. The integrated circuit according to claim 1, wherein, The first resonant structure comprises a single resonant ring.

8. The integrated circuit according to claim 1, wherein, The first resonant structure comprises a two-stage resonant structure.

9. The integrated circuit according to claim 1, wherein, The photonic device comprises a multiplexer.

10. The integrated circuit according to claim 1, wherein, The photonic device comprises a demultiplexer.

11. The integrated circuit according to claim 1, wherein, The photonic device comprises a Mach-Zehnder interferometer.

12. The integrated circuit according to claim 1, wherein, The photonic device further comprises: A third photodetector electrically connected to the electronic circuit; A fourth waveguide optically connected to the third photodetector; A fifth waveguide optically connected to the third photodetector; and A second resonant structure located between the first waveguide and the fourth waveguide, wherein the second resonant structure is configured to optically couple the first waveguide to the fourth waveguide; A second redundant resonant structure located between the first waveguide and the fifth waveguide, wherein the second redundant resonant structure is configured to optically couple the first waveguide to the fifth waveguide.

13. The integrated circuit according to claim 12, wherein, The first resonant structure has the same structure as the second resonant structure.

14. The integrated circuit according to claim 12, wherein, The first resonant structure has a structure different from that of the second resonant structure.

15. An integrated circuit, comprising: an electronic circuit; and a photonic device, wherein the photonic device includes: a first photodetector electrically connected to the electronic circuit; a second photodetector electrically connected to the electronic circuit through a first contact; a first waveguide configured to receive an optical signal input, wherein the first waveguide is optically connected to the first photodetector; a second waveguide optically connected to the second photodetector; a third waveguide optically connected to the second photodetector; a first resonant structure located between the first waveguide and the second waveguide, wherein the first resonant structure is configured to optically couple the first waveguide to the second waveguide; and a second resonant structure located between the first waveguide and the third waveguide, wherein the second resonant structure is configured to optically couple the first waveguide to the third waveguide; a controller including a control element, wherein the controller is configured to tune the second resonant structure to selectively couple the first waveguide to the third waveguide; a highly doped region located on both sides of the second photodetector; a doped region extending from the highly doped region towards the second photodetector, wherein the sidewalls and the bottom surface of the second photodetector are in contact with the doped region, wherein the doped region provides an electrical connection between the second photodetector and the first contact through the highly doped region and a first interconnect structure located above the highly doped region.

16. The integrated circuit according to claim 15, further comprising: a heater located above each of the first waveguide and the second waveguide; a second interconnect structure located above the heater; and a second contact located above the second interconnect structure and electrically connected to the heater through the second interconnect structure.

17. The integrated circuit according to claim 15, wherein, The controller is configured to tune the second resonant structure based on the current between the first photodetector and the electronic circuit.

18. The integrated circuit according to claim 15, wherein, The second resonant structure is configured to optically couple the first waveguide to the third waveguide during the entire operation of the photonic device.

19. The integrated circuit according to claim 15, wherein, The photonic device includes a multiplexer or a demultiplexer.

20. A method of using an integrated circuit, the method comprising: monitoring the current between a first photodetector and an electronic circuit; determining whether the monitored current is abnormal; and in response to determining that the monitored current is abnormal, controlling a resonant structure through a controller to optically couple a first waveguide connected to the first photodetector to a third waveguide connected to a second photodetector different from the first photodetector using at least one redundant resonant structure, wherein the second waveguide and the third waveguide are both connected to the second photodetector, and the second waveguide is optically coupled to the first waveguide through a first resonant structure. Wherein, the second photodetector is electrically connected to the electronic circuit through a contact, and an electrical connection is provided between the second photodetector and the contact through highly doped regions located on both sides of the second photodetector, doped regions extending from the highly doped regions towards the second photodetector, and an interconnect structure located above the highly doped regions, wherein sidewalls and a bottom surface of the second photodetector are in contact with the doped regions.

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