Patent Application
20250216708
The disclosed implementations relate generally to systems and methods used in data processing and communication, and in particular to those for optical data transfer.
Demands for artificial intelligence (AI) computing, such as machine learning (ML) and deep learning (DL), are increasing faster than can be met by increases in available processing capacity. This rising demand and the growing complexity of AI models drive the need to connect many chips into a system where the chips can send data between each other with low latency and at high speed. Performance when processing a workload is limited by memory and interconnect bandwidth. In many conventional systems, data movement leads to significant power consumption, poor performance, and excessive latency. Thus, multi-node computing systems that can process and transmit data between nodes quickly and efficiently may be advantageous for the implementation of (ML) models.
The subject matter discussed in this section should not be assumed to be prior art merely because of its mention in this section. Similarly, a problem mentioned in this section or associated with the subject matter provided as background should not be assumed to have been previously recognized in the prior art. The subject matter in this section merely represents different approaches, which in and of themselves can also correspond to implementations of the claimed technology.
In some aspects, the techniques described herein relate to a package including: a substrate configured to be electrically coupled with a heater power source on a first substrate side; a photonic integrated circuit (PIC) including a modulator with a first heater and a photodetector with a second heater, the PIC having a first side electrically coupled with a second side of the substrate; and an electronic integrated circuit (EIC) including a temperature controller configured to control localized heating of the modulator by the first heater in response to determining a first condition and/or localized heating of the photodetector by the second heater in response to determining a second condition, wherein the EIC has a first side electrically coupled with a second side of the PIC.
In some aspects, the techniques described herein relate to a method of temperature compensation in a PIC that includes a modulator and/or a photodetector, the method including: determining a sensed temperature in or near the PIC, wherein the sensed temperature is representative of a device temperature (a temperature of the modulator and/or the photodetector); and communicating the sensed temperature from the PIC to a temperature controller in an EIC and performing a first action, a second action, or both, based on the sensed temperature; wherein the first action includes: (1) determining a heater power control signal; (2) communicating the heater power control signal to a heater power source; (3) in the heater power source, generating heater power based on the heater power control signal; and (4) applying the heater power to a heater positioned near the modulator and/or the photodetector; and wherein the second action includes: (5) determining a device bias control signal; (6) communicating the device bias control signal to a bias source; (7) in the bias source, generating a bias based on the device bias control signal; and (8) applying the bias to the photodetector and/or the modulator.
In some aspects, the techniques described herein relate to a method of temperature compensation in a PIC that includes a modulator and/or a photodetector, the method including: receiving temperature information; using the temperature information to determine a heater power control signal and a bias control signal; using the heater power control signal to generate heater power and applying the heater power to a heater, wherein the heater locally heats the modulator and/or the photodetector; determining if the heater power is at a maximum level; and based on determining that the heater power is at the maximum level, using the bias control signal to modify a modulator bias level and/or a photodetector bias level.
In some aspects, the techniques described herein relate to a method of calibrating a thermal control system in a package that includes a temperature sensor, a PIC and an EIC, and wherein the PIC includes a modulator and a photodetector, the method including: looping back the modulator to the photodetector to enable measuring an optical modulation amplitude (OMA) of the modulator; setting a temperature of the PIC and the EIC at a target operating temperature (T1) and letting the PIC and EIC reach thermal equilibrium; determining a first sensor signal (ST1) to calibrate a sensor offset; setting the temperature of the PIC and the EIC at a second operating temperature (T2) and letting the PIC and EIC reach thermal equilibrium; determining a second sensor signal (ST2) to calibrate a sensor sensitivity slope; and using ST1 and ST2 to create a table or calibrate a model for operating temperatures between T1 and T2.
The technology will be described with reference to the drawings, in which:
In the figures, like reference numbers may indicate functionally similar elements. The systems and methods illustrated in the figures—and described in the Detailed Description below—may be arranged and designed in a wide variety of different implementations. Neither the figures nor the Detailed Description are intended to limit the scope as claimed. Instead, they merely represent examples of different implementations.
Data processing and data communication systems increasingly use photonic components such as photonic integrated circuits (PICs) in combination with electronic integrated circuits (EICs) to transfer and otherwise process data quickly. PICs may be electrically coupled with EICs, and optically or photonically coupled with optic fibers, other PICs, and other photonic components and devices. An EIC may be mounted on a PIC or vice versa, and therefore the two may also be physically and thermally coupled.
A PIC may include a modulator to modulate light (that comes from an internal or external light source) with data provided by a driver circuit in the EIC (or other electronic device) and it may include a photodetector (PD), usually a photodiode, to detect information in modulated light. The photodetector in turn may interface with the/an EIC that further processes its signals and extracts its data.
Both modulators and photodetectors are physical devices whose behavior and performance depends on various physical parameters, including the temperature, bias voltages, and other factors. The affected behavior and performance include speed, dynamic range, sensitivity, insertion loss (IL), optical modulation amplitude (OMA), and other specifications. A set of required specifications may be reliably achieved over a temperature range known as the operating temperature range. The ‘natural’ operating temperature range of photonic devices such as modulators and photodetectors may be smaller than required for many practical applications. In those cases, temperature compensation may help to extend the usability of these devices.
As described in U.S. patent application Ser. No. 18/742,028, “An Optically Bridged Multicomponent Package with Extended Temperature Range”, methods to extend the operating temperature range of an electroabsorption modulator (EAM) include modifying its bias voltage or current dependent on the EAM's temperature or estimated temperature. A similar technique may be used for a photodetector. Very localized heating of the EAM and/or photodetector is another option. Heating is an expensive temperature compensation in terms of the required power, compared to modifying a bias. Yet, the technology disclosed herein may use heating before bias modification. To determine the amount of heating, some implementations measure only the modulator or photodetector temperature and heat the PIC locally at the site of the modulator or photodetector. Other implementations may further measure the overall PIC temperature.
Heating a device (modulator or photodetector) impacts its measured temperature, resulting in a negative feedback system where enough heat is applied to keep a device at a desired temperature, for example the highest target operating temperature. This works like a thermostat, and implementations take care that not more heat is applied than safe for the heater's reliability. When the device temperature drops below the desired temperature and maximum heat is applied, bias modification will provide further temperature compensation that keeps the device specifications within the desired range.
When a PIC includes both modulators and photodetectors, methods and systems for temperature compensation may be combined. In some implementations, both the EAM and the PD are temperature compensated by using localized heating, but only the EAM uses bias modification to further extend the operating temperature range. This document discloses systems and methods for the combined temperature compensation of photodetectors and modulators.
As used herein, the phrase “one of” should be interpreted to mean exactly one of the listed items. For example, the phrase “one of A, B, and C” should be interpreted to mean any of: only A, only B, or only C.
As used herein, the phrases at least one of and one or more of should be interpreted to mean one or more items. For example, the phrase “at least one of A, B, or C” or the phrase “one or more of A, B, or C” should be interpreted to mean any combination of A, B, and/or C. The phrase “at least one of A, B, and C” means at least one of A and at least one of B and at least one of C.
Unless otherwise specified, the use of ordinal adjectives first, second, third, etc., to describe an object, merely refers to different instances or classes of the object and does not imply any ranking or sequence.
The terms “comprising” and “consisting” have different meanings in this patent document. An apparatus, method, or product “comprising” (or “including”) certain features means that it includes those features but does not exclude the presence of other features. On the other hand, if the apparatus, method, or product “consists of” certain features, the presence of any additional features is excluded.
The term “coupled” is used in an operational sense and is not limited to a direct or an indirect coupling. “Coupled to” is generally used in the sense of directly coupled, whereas “coupled with” is generally used in the sense of directly or indirectly coupled. Coupled in an electronic system may refer to a configuration that allows a flow of information, signals, data, or physical quantities such as electrons between two elements coupled to or coupled with each other. In some cases, the flow may be unidirectional, in other cases the flow may be bidirectional or multidirectional. Coupling may be galvanic (in this context meaning that a direct electrical connection exists), capacitive, inductive, electromagnetic, optical, or through any other process allowed by physics.
The term “connected” is used to indicate a direct connection, such as electrical, optical, electromagnetic, or mechanical, between the things that are connected, without any intervening things or devices.
The term “configured” to perform a task or tasks is a broad recitation of structure generally meaning having circuitry that performs the task or tasks during operation. As such, the described item can be configured to perform the task even when the unit/circuit/component is not currently on or active. In general, the circuitry that forms the structure corresponding to configured to may include hardware circuits, and may further be controlled by switches, fuses, bond wires, metal masks, firmware, and/or software. Similarly, various items may be described as performing a task or tasks, for convenience in the description. Such descriptions should be interpreted as including the phrase configured to.
As used herein, the term “based on” is used to describe one or more factors that affect a determination. This term does not foreclose the possibility that additional factors may affect the determination. That is, a determination may be solely based on specified factors or based on the specified factors as well as other, unspecified factors. Consider the phrase “determine A based on B”. This phrase specifies that B is a factor that is used to determine A or that affects the determination of A. This phrase does not foreclose that the determination of A may also be based on some other factor, such as C. This phrase is also intended to cover an implementation in which A is determined based solely on B. The phrase based on is thus synonymous with the phrase based at least in part on.
The terms “substantially”, “close”, “approximately”, “near”, and “about” refer to being within minus or plus 10% of an indicated value, unless explicitly specified otherwise.
The following terms or acronyms used herein are defined at least in part as follows:
“Above”, “below”, “top”, and “bottom”—the bottom of a package is considered to be the side of the package where it is prepared for mounting on and electrical coupling with a printed circuit board or other substrate. Hence the top of the package is the opposing side. Devices inside the package, such as integrated circuits, substrates, interposers, etc. are considered to have a bottom towards the bottom of the package and a top towards the top of the package. Thus, in a package, below means towards the bottom of the package and above means towards the top of the package. However, integrated circuits may be mounted upside down (flip-chip mounting) and thus their top is oriented towards the bottom of the package and their bottom is oriented towards the top of the package. For an integrated circuit, the bottom is considered to be the side of the semiconductor substrate and the top is considered to be the side of its electronic devices, such as transistors and passive devices. In a chip, above means towards the top of the chip, and below means towards the bottom of the chip.
Photodetectors, such as photodiodes, are commonly employed to convert optical energy into electrical energy. It is advantageous for a PD to capture a higher amount of light, as increased light absorption can lead to improved efficiency in converting optical energy to electric energy. Consequently, the PD becomes more responsive to low light levels with enhanced signal-to-noise ratio. However, the temperature and bias significantly impact the performance of PDs. Low temperature affects the energy band structure and reduces the absorption of photons. In a PIC, PDs may need to operate across a wide ambient temperature range (e.g., from 85° C. to 25° C.), but varying ambient temperatures can lead to undesirable fluctuations in the PD's performance.
The techniques implemented herein can maintain a stable PD performance over an extended temperature range (e.g., from 85° C. to 25° C.) by deploying a thermal control system. The thermal control system monitors temperatures of PDs and provides heating and/or bias compensation to widen the operating temperature range of the PDs. The thermal control system receives temperature-dependent electrical signals from a temperature sensor or it receives other information that measures or allows estimating or predicting the temperature of one or more PDs in a limited region of the PIC. It then determines whether heating must be applied, and if a bias adjustment must be made. It applies the heating and/or provides the bias to the PDs in the applicable region. When bias control is applied in at least a part of an extended temperature range, the behavior of the PDs due to the applied temperature-dependent bias correlates inversely with the PDs' temperature dependence, widening the operating temperature range to the extended temperature range. Therefore, the PD performance can be improved across the extended temperature range.
Similarly, these techniques can help provide a stable performance of modulators such as EAMs over an extended temperature range (e.g., from 85° C. to 25° C.). The thermal control system monitors temperatures of EAMs and provides heating and bias control compensation to widen the operating temperature range of the EAMs in the PIC's region of which the temperature was sensed, estimated, or predicted. The thermal control system receives temperature-dependent electrical signals from a temperature sensor or it receives other information that allows estimating or predicting the temperature of the EAMs. It then determines whether heating must be applied, and if a bias adjustment must be made. It applies the heating and/or provides the bias to the EAMs in the applicable region. In at least a part of an extended temperature range, the behavior of the EAMs due to the applied temperature-dependent bias correlates inversely with the EAMs' temperature dependence, widening the operating temperature range to the extended temperature range. Thus, the EAM performance can be improved across the extended temperature range.
PCB 120 provides for interconnection of devices and modules mounted on it. It may include a signal bus 122, for example a serial bus such as a Serial Peripheral Interface (SPI) bus or Inter-Integrated-Circuit (I2C) bus. Implementations may use signal bus 122 to communicate between EIC 114, heater power source 130, bias source 140, and any other devices that provide information for EIC 114 or that must be controlled by EIC 114. PCB 120 further provides electrical connections that provide one or more biases from bias source 140 to package 110 and that provide heater power from heater power source 130 to one or more destinations in package 110.
Package 110 may include, for example, a substrate 115 and an interposer 116. Substrate 115 may not include any integrated devices. Substrate 115 provides at least partially vertical conductive pathways (also called through-vias or through-silicon-vias (TSVs)) to couple various signals into and out of PCB 120 and into and out of PIC 112. Substrate 115 is configured to receive heater power from heater power source 130 and to forward the heater power to the PIC and/or to receive bias levels from bias source 140 and to forward the bias levels to the PIC. Substrate 115 is further configured to couple PIC 112 and EIC 114 with signal bus 122. Interposer 116 is located between substrate 115 and both PIC 112 and XPU 117. XPU 117 may be, for example, a CPU, a GPU, a coarse-grained reconfigurable architecture (CGRA), a field-programmable array (FPGA), or any other processor or AI accelerator. Interposer 116 may be, for example, a silicon interposer, or any other component that can be placed between semiconductor and other devices that provided electrical routing of signals between the devices, and that may additionally help provide thermal management. In this example, interposer 116 may provide electrical coupling between XPU 117, PCB 120, EIC 114, and any other devices and systems that are within or coupled with the package. For example, interposer 116 may couple a package temperature sensor 118 with signal bus 122. Package temperature sensor 118 may sense a package temperature that may be representative of the temperature of a modulator and/or photodetector in PIC 112. PIC 112 may be coupled with an optical fiber 150 via optical interface 113, which may include, for example, a grating coupler (GC) and a fiber array unit (FAU).
Bias source 140 may include, for example, a converter which may include a DC-to-DC converter, a charge pump, or a linear regulator or other converter, and which receives input power at one voltage level and provides one or more biases at other voltage levels, or at current levels. The converter may be fixed or controllable. If it is controllable, bias source 140 may further include a signal interface that is coupled with signal bus 122 and that controls the level of the bias or biases based on signals it receives from EIC 114 via signal bus 122.
Heater power source 130 may also include a converter with a DC-to-DC converter, a charge pump, a linear regulator or other converter that receives input power at one voltage level and that provides heater power at one or more other voltage levels or current levels. The converter may be fixed or controllable. If it is controllable, heater power source 130 may further include a signal interface SI that is coupled with signal bus 122 and that controls the level of the heater power (for example, in the form of controlled heater currents) based on signals it receives from signal bus 122.
The level of activity of EIC 114 and XPU 117 may impact the die temperature of PIC 112, and thus, indirectly, the junction temperatures of devices operating within PIC 112. This includes the junction temperature of photodiodes (or more generally, devices included in photodetectors) and of EAMs (or more generally, devices included in modulators). The PIC's operating temperature range is the (presumed average) die temperature range within which the PIC operates according to its published specifications. However, the junction temperatures at specific devices within the PIC may be higher or lower than the average die temperature. The performance of these devices depends not only on their junction temperature, but also on their bias (voltage or current), and potential other factors. To operate the devices optimally, given the PIC die temperature as impacted by the ambient temperature including effects caused by the level of activity of EIC 114 and XPU 117, an implementation may provide a thermal control system that applies bias and temperature compensation as disclosed herein. The bias and temperature compensation result in an extended operating temperature range for the PIC.
Whereas both photodetector 320 and modulator 330 receive a bias, which can be a semi-stationary voltage or current, amplifier 350 and driver 360 may be coupled for fast changing signals only, e.g., via a capacitor, or for both fast changing and slow changing signals, e.g., without a capacitor. Loosely speaking, the bias is said to be “DC coupled” (direct current) whereas the data signals may be either DC coupled or “AC coupled” (alternating current). Photodetector 320 may be a photodiode, which typically needs to be “reverse biased” to operate, meaning that its anode must be at a lower voltage than its cathode. In case the photodiode is biased with a voltage, the bias voltage is applied to its anode with reference to its cathode and is negative. In case the photodiode is biased with a current, the current is sourced into the cathode, or sinked from the anode. Modulator 330 may be an EAM and may also be based on a diode. In that case, the diode again must be reverse biased for the modulator to operate. The EAM is usually biased with a voltage, and this voltage too must be negative.
Heater 342 is located very close (within a distance of thirty (30) microns) to photodetector 320, and in some implementations heater 342 is located directly above or under photodetector 320. Heater 343 is located very close (within a distance of thirty (30) microns) to modulator 330, and in some implementations heater 343 is located directly above or under modulator 330. It has been found that a heater can locally impact the temperature of PIC 112 within a radius of up to a few tens of microns. For this reason, the heaters can help provide temperature compensation for individual photodetectors and modulators. However, this may also require that individual measurements or estimates of those devices' temperatures are available.
PIC 112 may further include a light source 332, and a temperature sensor 340 or multiple temperature sensors. PIC 112 may act as another interposer for power, bias, and signals for EIC 114, such as for example with signal bus 122. EIC 114 may include an amplifier 350, for example a transimpedance amplifier (TIA) coupled with photodetector 320 in PIC 112; a (driver 360), coupled with a signal input of modulator 330 in PIC 112; a temperature controller 370, coupled with a signal output of temperature sensor 340 in PIC 112, and coupled with a signal interface 372; and an optional memory 374 to hold a table, software, or firmware that temperature controller 370 can uses for converting temperature information to bias control signals and heater power control signals that extend the effective operating temperature ranges of photodetector 320 and modulator 330. Signal interface 372 couples temperature controller 370 with signal bus 122 to allow it to receive information and dispatch bias control signals for bias source 140 and heater power control signals for heater power source 130.
Temperature controller 370 can use hardware, software, or firmware (or any combination of these), which implements logic configured to determine when and how much a thermal variable, such as a device temperature, diverges from an optimal range. Temperature controller 370 can use a look-up table, access a database, compute a value using thermal model, or use some other means to determine when and how much to vary a device's (or group of devices) heater power and/or bias. In one implementation, temperature controller 370 obtains heater power control data and bias control data by using a table, a database, or another suitable data structure. For example, a table can have multiple rows and columns where each row has at least a first column to represent a present temperature (or signal associated with the temperature), a corresponding second column to represent associated heater power control data, and a corresponding third column to represent associated bias control data.
Optical interface 113 may receive optical signals from optical fiber 150 and send the received optical signals to photodetector 320, for example via one or more photonic waveguides and other photonic devices. Photodetector 320 converts the optical signals to electrical signals, which it sends to amplifier 350. Amplifier 350 amplifies the electrical signals and prepares them for digitization. Ultimately, EIC 114 may process the digitized signals and/or send the digitized signals to XPU 117 and/or other destinations.
Driver 360 receives electrical signals, for example from XPU 117 and/or other sources, or from processes internal to EIC 114, and prepares the electrical signals for modulation by modulator 330. Modulator 330 receives light, for example unmodulated light, from light source 332, and modulates the light with information received from driver 360. Modulator 330 may send the modulated light to optical fiber 150 via one or more photonic waveguides and/or other photonic devices and optical interface 113.
Although
The node(s) 620 in EIC 114 may be optically coupled by waveguide(s) 630A-C in PIC 112, so that communication from for example node(s) 620A to node(s) 620C may travel via waveguide(s) 630A, node(s) 620B, and waveguide(s) 630B. In some implementations the light source(s) for the modulators may be on-chip, whereas in other implementations the light source(s) may be off-chip, and light is provided through one or more optical interfaces.
An incoming message from optical fiber 150 travels through optical interface 113 and waveguide 640 to photodetector 320A, which converts the optical signal to an electrical signal for amplifier 350A and for further processing in node(s) 620A. An outgoing message from node(s) 620A travels to optical fiber 150 via a driver and a modulator (both not shown), and optical interface 113. Photodetectors optically coupled with optical interface 113 (e.g., for inter-chip communication) may be of a different type than photodetectors used for communication between different parts of EIC 114 (e.g., intra-chip communication). For example, a photodetector used for inter-chip communication may be an edge PD or corner PD. Thus, PIC 112 may host multiple types of photodetectors, and similarly it may host multiple types of modulators. Each type of photodetector or modulator may have its own dependencies on bias and temperature, therefore, temperature controller 370 stores heater power control data and bias control data as a function of the temperature for each type of photodetector and each type of modulator. In some implementations, temperature controller 370 stores heater power control data and bias control data as a function of the temperature for each some or all individual photodetectors and modulators. An implementation may have multiple units of heater power source 130 and bias source 140, or conversely, bias source 140 may generate a separate bias level for each type of photodetector and/or modulator, and heater power source 130 may generate a separate heater power level for each type of photodetector and/or modulator. Some implementations may have multiple units of temperature controller 370, each one dedicated to a type of photodetector or modulator. Implementations may use temperature controllers at a finer granularity, for example the implementations may dedicate a slice of a temperature controller's time to each type in a cluster of node(s) 620, in one of the node(s) 620, or even dedicated to individual photodetectors and modulators. Temperature information for the temperature controller(s) may come from temperature sensors on the PIC. Generally, the finer the temperature control granularity, the more temperature sensors may be needed. For example, an implementation that compensates for temperature dependence of all devices in a cluster of node(s) 620 may need one temperature sensor in that cluster. An implementation that compensates for temperature dependence of all devices in individual node(s) 620 may need one temperature sensor per node(s) 620.
Modulated light travels through waveguide 324A into semiconductor waveguide 323 which is, or includes, the intrinsic semiconductor material. A PD generally has no exit for photonic signals, so only waveguide 324A has been drawn. Waveguide 324A has a tapered tip 325A, for example made of polycrystalline silicon (or poly) to minimize light losses in the transition to semiconductor waveguide 323. Semiconductor waveguide 323 (and parts of anode 321 and cathode 322) may be made of germanium silicon (GeSi), for example. Anode 321 is doped to have a shortage of free electrons (P-type semiconductor material) and cathode 322 is doped to have an excess of free electrons (N-type semiconductor material).
The photodiode is zero-biased or reverse biased, that is, the anode is at the same or a lower voltage than the cathode, and when there is no light traveling into semiconductor waveguide 323, only a leakage current known as the dark current flows between the cathode and the anode. When light enters semiconductor waveguide 323, the current can strongly increase, dependent on the optical power and on the photodiode bias. To capture a signal that is proportional to the optical power, the implementation must measure the fast or AC changes in the current.
In some implementations, the photodetector 320 comprises a material selected from one or more of germanium, silicon, an alloy of germanium, an alloy of silicon, a III-V material based on indium phosphide (InP), and a III-V material based on gallium arsenide (GaAs). In some implementations, photodetector 320 comprises about 99% germanium and about 1% silicon (e.g., more than 99% germanium and less 1% silicon).
Light that may be unmodulated travels through waveguide 324A into semiconductor waveguide 323 which is, or includes, the intrinsic semiconductor material, and out of semiconductor waveguide 323 at the other end into waveguide 324B. Waveguide 324A has a tapered tip 325A, for example made of polycrystalline silicon (or poly) to minimize light losses in the transition to semiconductor waveguide 323 and similarly, waveguide 324B has a tapered tip 325B to minimize light losses in the transition from semiconductor waveguide 323. Semiconductor waveguide 323 (and parts of anode 321 and cathode 322) may be made of germanium silicon (GeSi), for example. Anode 321 is doped to have a shortage of free electrons (P-type semiconductor material) and cathode 322 is doped to have an excess of free electrons (N-type semiconductor material).
The PIN diode is zero-biased or reverse biased, that is, the anode is at the same voltage as or a lower voltage than the cathode. Using the Franz-Keldysh effect, an implementation varies the optical absorption level of semiconductor waveguide 323 by changing the voltage across the PIN diode. Thus, an implementation as EAM uses the voltage over the PIN diode (or the current through the diode) as a parameter to modulate the light that travels through semiconductor waveguide 323. For example, in an implementation the cathode may receive an AC signal that has a swing of −1 to +1 V. To ensure that the PIN diode is always reverse biased, if the bias is applied to the anode, its highest value must be lower than −1 V, for example −1.2 V. For an implementation in which the signal is DC coupled and has a swing of 0 to 2 V, the maximum value of the bias voltage should be lower than 0 V, for example, −0.2 V.
In some implementations, the modulator 330 comprises a material selected from one or more of germanium, silicon, an alloy of germanium, an alloy of silicon, a III-V material based on indium phosphide (InP), and a III-V material based on gallium arsenide (GaAs). In some implementations, modulator 330 comprises about 99% germanium and about 1% silicon (e.g., more than 99% germanium and less 1% silicon).
Many variations of the EAM and photodiode designs are possible, and shapes and sizes mentioned here are idealized examples. Materials may vary between implementations, and thicknesses of layers may vary because the etching process doesn't follow precise orthogonal plans. All such variations are within the scope and ambit of this disclosure.
Some implementations combine 1230 and 1240. For example, an implementation may determine heater control signals for temperatures including the target operating temperature, for which it may determine a heater power control signal that indicates that no heater power is generated. Another implementation may generate the heater power control signal in a thermostat loop, where the heater power to be generated depends on a difference between the device temperature and a target operating temperature.
Although implementations may use a temperature difference to determine the heater power control signal, they use the device temperature itself (measured, estimated, or predicted) to determine the bias control signal. An implementation may determine the bias control signal from a temperature model (i.e., by calculation) or from a table.
Described implementations of the subject matter can include one or more features, alone or in combination, as described in the following clauses.
Clause 1. A package comprising:
using the temperature information includes at least one of reading, estimating, or predicting a device temperature from the temperature information, wherein the device temperature is a temperature of the modulator and/or the photodetector.
Clause 21. A method of calibrating a thermal control system in a package that includes a temperature sensor, a PIC and an EIC, and wherein the PIC includes a modulator and a photodetector, the method comprising:
Although the description has been described with respect to specific implementations thereof, these specific implementations are merely illustrative, and not restrictive. The description may reference specific structural implementations and methods and does not intend to limit the technology to the specifically disclosed implementations and methods. The technology may be practiced using other features, elements, methods and implementations. Implementations are described to illustrate the present technology, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art recognize a variety of equivalent variations on the description above. For example, temperature controller 370 may be a microcontroller, an optimized digital signal processor (DSP), a dedicated (i.e., hardwired) digital circuit, a configured digital circuit (e.g., in an FPGA), and any other circuit that can perform the functions described herein. Also, although this specification mentions specific sizes and distances, those may change with the applied manufacturing technology.
All features disclosed in the specification, including the claims, abstract, and drawings, and all the steps in any method or process disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in the specification, including the claims, abstract, and drawings, can be replaced by alternative features serving the same, equivalent, or similar purpose, unless expressly stated otherwise.
Although the description has been described with respect to specific implementations thereof, these specific implementations are merely illustrative, and not restrictive. For instance, many of the operations can be implemented on a printed circuit board using off-the-shelf devices, in a System-on-Chip (SoC), application-specific integrated circuit (ASIC), programmable processor, a CGRA, or in a programmable logic device such as an FPGA, obviating the need for at least part of any dedicated hardware. Implementations may be as a single chip, or as a multi-chip module (MCM) packaging multiple semiconductor dies in a single package. All such variations and modifications are to be considered within the ambit of the disclosed technology the nature of which is to be determined from the foregoing description.
Any suitable technology for manufacturing electronic devices can be used to implement the circuits of specific implementations, including CMOS, FinFET, GAAFET, BiCMOS, bipolar, JFET, MOS, NMOS, PMOS, HBT, MESFET, etc. Different semiconductor materials can be employed, such as silicon, germanium, SiGe, GeSi, GaAs, InP, GaN, SiC, graphene, etc. Circuits may have single-ended or differential inputs, and single-ended or differential outputs. Terminals to circuits may function as inputs, outputs, both, or be in a high-impedance state, or they may function to receive supply power, a ground reference, a reference voltage, a reference current, or other. Although the physical processing of signals may be presented in a specific order, this order may be changed in different specific implementations. In some specific implementations, multiple elements, devices, or circuits shown as sequential in this specification can operate in parallel.
Different integration technologies can be used for a PIC, such as silicon photonics, InP, silicon nitride, hybrid and heterogeneous integration technologies, etc. Implementations may use different technologies for optical modulators, including Mach-Zehnder, microring resonator, SiGe electroabsorption modulator, Franz-Keldysh electroabsorption modulators, a quantum-confined Start effect (QCSE) electroabsorption modulator, a quantum well cell (QWC), etc. PICs may operate at any wavelength band. Any type of laser source can be employed, like distributed feedback lasers, laser diodes, hybrid integrated InP lasers, multiwavelength laser sources, microcomb light generator sources, etc. Different technologies can be implemented for photodiodes, such as SiGe electro-absorption photodiodes, InP photodiodes, avalanche photodiodes, etc.
It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application.
Thus, while specific implementations have been described herein, latitudes of modification, various changes, and substitutions are intended in the foregoing disclosures, and it will be appreciated that in some instances some features of specific implementations will be employed without a corresponding use of other features without departing from the scope and spirit as set forth. Therefore, many modifications may be made to adapt a particular situation or material to the essential scope and spirit.
This application claims benefit to U.S. provisional patent application Ser. No. 63/616,430, entitled “Photonic Interconnect Platform for Memory and Compute”, filed on Dec. 29, 2023. This application is related to U.S. patent application Ser. No. 18/123,083, entitled, “OPTICAL MULTI-DIE INTERCONNECT BRIDGE (OMIB)”, filed on Mar. 17, 2023, now U.S. Pat. No. 11,835,777; U.S. patent application Ser. No. 18/742,028, filed on Jun. 13, 2024; U.S. patent application Ser. No. 18/243,474, filed Sep. 7, 2023, now U.S. Pat. No. 12,124,095; U.S. patent application Ser. No. 18/376,474, filed Oct. 4, 2023; International Patent Application No. PCT/US23/15467, filed Mar. 17, 2023; U.S. patent application Ser. No. 18/751,021, filed on Jun. 21, 2024; U.S. patent application Ser. No. 18/751,086, filed on Jun. 21, 2024; U.S. patent application Ser. No. 18/751,101, filed on Jun. 21, 2024; U.S. patent application Ser. No. 18/751,105, filed on Jun. 21, 2024; U.S. patent application Ser. No. 18/757,084, filed on Jun. 27, 2024; and U.S. patent application Ser. No. 18/757,182; filed on Jun. 27, 2024. Each publication, patent, and/or patent application mentioned in this specification is herein incorporated by reference in its entirety to the same extent as if each individual publication and/or patent application was specifically and individually indicated to be incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63616430 | Dec 2023 | US |
