A serially co-driven semiconductor optical amplifier assembly, optical module and control method

Abstract

The application discloses a series and co-driven semiconductor optical amplifier assembly, an optical module and a control method. In the assembly, a semiconductor optical amplifier chip and a thermoelectric refrigerator are connected in series in a main working current path, and the same working current flows through the semiconductor optical amplifier chip and the thermoelectric refrigerator in turn; the semiconductor optical amplifier chip is coupled with a cold end of the thermoelectric refrigerator; and the polarity of the thermoelectric refrigerator is set as follows: when a forward working current is input, the thermoelectric refrigerator pumps heat from the cold end to the hot end. The thermoelectric parameters and the heat transfer parameters can be matched according to a complete package, and the working current can be adjusted according to optical monitoring, so that the current adjusts the carrier injection and the heat pumping state at the same time. Preferably, the package does not set an independent and controlled high-current channel of the thermoelectric refrigerator. The application can reduce high-current driving resources and power ends, suppress the drift of optical performance with temperature, and is suitable for coherent, incoherent optical modules and other optical amplification systems.

Description

Technical Field

[0001] This invention relates to the fields of optical communication, semiconductor optoelectronic devices and packaging thermal management technology, and in particular to a series common-drive semiconductor optical amplifier component, optical module and control method. Background Technology

[0002] In systems such as optical communication, optical interconnect, optical line amplification, lidar, and optical sensing, semiconductor optical amplifiers are often required in the optical path to amplify the power or adjust the gain of continuous light, modulated light, pulsed light, or burst light. Although different applications have different input light forms and control objectives, the gain, output capability, spectral characteristics, and efficiency of semiconductor optical amplifiers are generally affected by the junction temperature.

[0003] A coherent optical transmission link is a typical scenario in the aforementioned applications, typically including a light source, a coherent optical modulator, and an optical power adjustment or amplification unit located after the modulator. The coherent optical modulator, coupler, polarization processing structure, and encapsulated optical path introduce insertion loss. To meet the module's transmit optical power and link budget requirements, an optical amplifier can be placed after the modulator.

[0004] A common approach is to construct an erbium-doped fiber amplifier using a pump laser and erbium-doped fiber. The pump laser can be a three-pin device with a monitoring end, used in conjunction with a pump driver, wavelength division multiplexer, erbium-doped fiber, and related optical paths. This approach offers relatively mature amplification performance, but it requires a large number of components and has a large fiber winding space, resulting in higher optical path assembly, power consumption, and cost, which is not conducive to further miniaturization and integration.

[0005] SOA (Optically Arrayed Optical Assemblies) offer advantages such as small size, ease of chip-level packaging, fast response speed, and convenient integration with coherent optical modules, making them suitable as gain units after modulators. However, the material gain, saturated output power, noise characteristics, gain spectrum peaks, and electro-optical efficiency of SOA are all related to junction temperature. As ambient temperature increases, SOA typically exhibits phenomena such as decreased gain, increased current required to achieve the same output optical power, gain spectrum characteristic drift, and reduced efficiency. Increased drive current further increases the power consumption and self-heating of the SOA, leading to significant electro-thermal-optical coupling.

[0006] Existing temperature-controlled SOA packages typically place the SOA at the cold end of the temperature control circuit (TEC) and provide separate drive current paths for the SOA and TEC. The TEC path often requires a separate bidirectional or unidirectional power stage, temperature sensor, and temperature control circuitry, occupying additional current pins on the package or module interface. Furthermore, the optical power loop and temperature loop may interact, increasing the complexity of loop tuning, fault protection, and system verification.

[0007] Simply connecting an existing SOA (Optical System) directly in series with an existing TEC (Digital Transistor) will not naturally provide stable temperature compensation. The cold-end heat load power of the SOA varies with operating current, input optical power, junction temperature, and photoelectric conversion efficiency; the cold-end pumping heat power of the TEC includes a Peltier term approximately proportional to the current, a Joule heating term proportional to the square of the current, and a heat conduction recirculation term related to the temperature difference between the hot and cold ends. Chip interconnects, vapor chambers, leads, packaging atmosphere, housing, and external heat sinks also alter the actual thermal boundary. Therefore, mismatch between the two characteristic curves can lead to insufficient cooling at high temperatures, overcooling at low temperatures, loss of monotonicity in the output optical power-current relationship, closed-loop oscillation, or localized thermal runaway.

[0008] Therefore, a universal optical amplification structure based on SOA and TEC sharing the main operating current is needed, along with thermal parameter matching and optical quantity control methods adapted to this structure, so that it can be used in coherent optical modules as well as other modules or systems with optical amplification requirements; in scenarios where packaging and driving are further simplified, it is also necessary to reduce the high current channels and power terminals of independent TECs. Summary of the Invention

[0009] This invention aims to provide a series co-drive component that simplifies the drive channel and package interface, based on the overall inventive concept of SOA and TEC sharing the main operating current. Furthermore, it provides an optical quantity control method suitable for this component, a complete package thermal boundary parameter matching method, and an optical module using this component, to improve the under-cooling, over-cooling, and optical performance drift problems that may occur in simple device series connections. To solve the above-mentioned technical problems, one aspect of this invention provides a series co-drive semiconductor optical amplifier component.

[0010] The component includes an optical input terminal, an optical output terminal, a semiconductor optical amplifier chip, a thermoelectric cooler, and a main operating current path. The semiconductor optical amplifier chip amplifies the light entering from the optical input terminal and outputs it from the optical output terminal. The semiconductor optical amplifier chip and the thermoelectric cooler are connected in series in the main operating current path, so that the operating current in the main operating current path flows sequentially through the semiconductor optical amplifier chip and the thermoelectric cooler. The cold end of the semiconductor optical amplifier chip and the thermoelectric cooler are thermally coupled, and the hot end of the thermoelectric cooler is thermally coupled to a predetermined heat dissipation boundary via a heat dissipation path. The electrical connection polarity between the semiconductor optical amplifier chip and the thermoelectric cooler is configured such that when the operating current flows through the main operating current path along the forward injection direction of the semiconductor optical amplifier chip, the thermoelectric cooler pumps heat from the cold end to the hot end.

[0011] The main operating current path can be connected in series with a current sensing resistor, a protective switch, a current limiting element, a filter element, a fuse element, and a connecting conductor. It is used for high-impedance or low-power connections for optical quantity detection, series path voltage detection, temperature detection, communication, or protection, and optionally for low-power heating elements, without changing the relationship between the SOA and TEC sharing the main operating current. In a preferred embodiment, no channel is provided that allows independent setting of the TEC high-current drive current relative to the main operating current; the package only provides a pair of high-current power terminals for the main operating current path.

[0012] The semiconductor optical amplifier chip can be thermally coupled to the cold end of the TEC via a chip connection layer and an optional thermally conductive heat dissipation structure. The hot end of the TEC can dissipate heat to the environment via a hot end connection layer, a package substrate, a module housing, and / or an external heat sink. In one embodiment, by selecting or adjusting at least one of the following: the thermoelectric parameters of the TEC, the heat transfer parameters from the SOA to the cold end, the heat transfer parameters from the hot end to the external heat dissipation boundary, and parasitic heat paths, the cold end heat pumping characteristics varying with the operating current within the target operating range are coordinated with the cold end thermal load power characteristics, thereby at least partially compensating for junction temperature changes caused by variations in operating current and / or ambient temperature. Preferably, the matching criteria are further used as thermal power residual, allowable junction temperature deviation, optical quantity drift, or the monotonicity of output optical power with respect to operating current.

[0013] The component may consist only of the aforementioned series common-drive electrical and thermal structure, or it may further include or be used in conjunction with an output monitoring photodetector, an input monitoring photodetector, a controller, and a current driver. The photodetector, controller, and current driver may be located within the component package, within the optical module, or in an external control circuit connected to the component, and therefore do not constitute essential components of the core structure of the component.

[0014] In one optional closed-loop implementation, the output monitoring photodetector receives a portion of the amplified output light via an optical splitter. The controller obtains an estimate of the target optical quantity based on the output monitoring signal and adjusts the operating current according to the deviation between the estimate and the target value. When the ambient temperature rises or the SOA gain decreases, resulting in low output optical power, the controller can increase the operating current; the increased current increases SOA carrier injection and, on the other hand, increases cold-end heat pumping power within the selected TEC heat pumping range, thereby suppressing junction temperature rise. When the ambient temperature decreases or the output optical power is too high, the controller can decrease the operating current while simultaneously reducing carrier injection and cooling capacity.

[0015] The component does not require the SOA junction temperature to be strictly controlled as a constant independent of the operating current. In embodiments employing thermal matching, the SOA junction temperature can follow a pre-designed compensation trajectory. The changes allow the effect of temperature on gain to be coordinated with the effect of current on carrier injection, while maintaining the controllability of optical quantities within the target operating range.

[0016] Another aspect of the present invention provides a control method, comprising acquiring an optical monitoring quantity characterizing the output state of the SOA, determining an operating current based on the relationship between the optical monitoring quantity and a target optical quantity, and applying the operating current to a series current path formed by the SOA and the TEC; thereby, the same operating current adjusts the pumping state of the TEC while simultaneously adjusting the carrier injection amount of the SOA. Output power closed-loop, constant gain closed-loop, temperature or input power feedforward, lookup table initial value, rate of change limitation, and anomaly protection are all possible further embodiments.

[0017] Another aspect of the present invention provides a parameter matching method under complete package thermal boundaries. This method obtains the characteristics of the cold-end thermal load power of the SOA as a function of the common operating current under predetermined package and heat dissipation boundaries, obtains the characteristics of the cold-end pump thermal power of a candidate TEC as a function of the common operating current, and selects or adjusts at least one of the TEC parameters and heat transfer parameters so that both characteristics meet predetermined requirements for junction temperature stability, optical performance stability, or thermal power residual within a target operating range. The operating current range, device pairing relationships, and control parameters can also be determined based on the matching results.

[0018] Another aspect of the present invention provides an optical module. The optical module includes a module optical path, a current driver, an SOA (Optical Linear Amplifier), and a TEC (Electronic Transceiver Unit). The SOA is located at the optical amplification position in the module optical path, and its current path is electrically connected in series with the TEC and supplied with the same operating current by the current driver. The optical module can be a coherent optical module, an incoherent optical module, an optical line amplification unit, a pluggable transceiver module, an onboard optical engine, a lidar source amplification module, or an optical sensing module. In a coherent optical module, the SOA can be located on the output side of the coherent optical modulator.

[0019] Thermal matching principle Under a common operating current I that makes the SOA positively injected and the TEC pump heat from the cold end to the hot end in the positive direction, the cold end heat pumping power of the TEC can be expressed as: In the formula, the first term is the Peltier pump heat term, the second term is the Joule heat term distributed to the cold end, and the third term is the heat conduction backflow term from the hot end to the cold end. For multi-stage TECs or thin-film TECs, equivalent models, lookup tables, or experimental fitting models that include inter-stage thermal coupling can be used to replace the above expressions.

[0020] The heat load power generated at the cold end by SOA and the parasitic path in the package can be expressed as: in, Input electrical power to the SOA; It is the difference between the total optical power output outward through the optical boundary of the cold-end system, including signal light and amplified spontaneous emission, and the total optical power input through the optical boundary; The parasitic heat load power flowing into the cold end system in the positive direction includes chip absorption, bonding wire and electrode heat conduction, optical element absorption, packaging atmosphere convection or conduction, thermal radiation, and heat leakage from the housing to the cold end. In cases where multiple chips are located at the cold end, the heat load power of other cold end devices should also be considered.

[0021] Within the target working domain, preset cold junction temperature can be achieved. Or preset junction temperature Candidate operating points were determined, and calculations were performed at each candidate operating point based on the thermoelectric model and the encapsulation thermal model. and Preferred use If the allowable temperature deviation is The equivalent thermal resistance between the cold junction thermal power residual and the temperature deviation can be calibrated through thermal simulation, calorimetry, or temperature scanning. and based on Set a preset thermal power tolerance. The actual steady-state equilibrium point is determined by... The boundary conditions of the fully encapsulated thermal network are jointly determined; the residual criterion is used to evaluate candidate operating points corresponding to preset temperatures, rather than setting the actual steady-state thermal balance difference to non-zero. This matching does not require each operating point to have the same cold junction temperature or junction temperature, but rather requires that the comprehensive deviation of junction temperature, optical power, gain spectrum, and efficiency meets the index within the target temperature range, input light range, and control current range.

[0022] To ensure closed-loop controllability of output optical power, the following is preferred: The first term reflects the gain increase brought about by the increase in carrier injection, and the second term reflects the junction temperature change caused by the change in cooling capacity due to the alteration of the series current. By matching the two terms to ensure that the overall slope after synthesis is positive and not too large within the operating range, multiple operating points can be prevented, and it is easier to set the controller gain.

[0023] The beneficial effects of this invention are: 1. SOA and TEC share the main operating current, which can reduce the need for independent high-current drive resources; in implementations without a separate high-current TEC channel, it can also reduce the need for dedicated TEC power stages, high-current power terminals and related wiring.

[0024] 2. The output optical power control current simultaneously undertakes carrier injection regulation and junction temperature compensation; when the gain decreases at high temperatures, increasing the two directions of current generation are consistent, which can improve the full-temperature range control capability.

[0025] 3. The matching objects cover SOA, TEC, interconnect layer, vapor chamber, package substrate, parasitic heat path and external heat dissipation conditions, which can avoid undercooling or overcooling caused by selecting only based on the power consumption of the bare die or the nominal maximum cooling capacity of the TEC.

[0026] 4. Optical monitoring and closed-loop control can be set in components, modules or external control circuits as needed for the product; in the implementation of a single optical quantity closed loop, temperature or voltage signals can be used as feedforward and protection information, thereby reducing the coupling tuning work between the independent optical power loop and temperature control loop.

[0027] 5. The component can be used for optical amplification after coherent modulator, as well as for continuous light, modulated light, pulsed light or burst light amplification scenarios such as incoherent optical modules, line amplification, optical interconnect, lidar and optical sensing; in coherent optical modules, it can replace at least part of the post-amplification structure composed of pump laser, erbium-doped fiber and related optical path.

[0028] 5. By limiting the operating current to the monotonic zone of the TEC pump thermal power and setting soft start, input light presence detection, compliance voltage verification and over-temperature protection, the safety of the series system during startup and under abnormal operating conditions can be improved. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in this invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the core structure of a series common-drive semiconductor optical amplifier component according to an embodiment of the present invention, as well as the optional output monitoring and external driving relationship.

[0031] Figure 2 This is a schematic cross-sectional view of the SOA, TEC, and complete package thermal boundary according to an embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram illustrating the cold-end thermal power matching and the monotonicity of output optical power with respect to series current in a preferred embodiment of the present invention.

[0033] Figure 4 This is a schematic diagram of the optical quantity closed-loop control and safety protection process according to one embodiment of the present invention.

[0034] Figure 5 This is a schematic diagram of a coherent post-amplification implementation method for an optical module employing a series common-drive semiconductor optical amplifier component.

[0035] Figure 6 This is a schematic diagram of the series current path topology for several embodiments of the present invention.

[0036] Explanation of reference numerals in the attached figures: 100-Semiconductor optical amplifier component; 110-Semiconductor optical amplifier chip; 111-Junction region or heat-generating region; 112-Heat-conducting vapor chamber substrate; 120-Thermoelectric cooler; 121-Cold junction; 122-Hot junction; 123-Thermocouple structure; 130-Packaging substrate; 131-Packaging housing; 140-Main operating current path; 141-Forward power terminal; 142-Return power terminal; 150-Optical input terminal; 160-Optical output terminal; 170-Optical splitter; 180-Output monitoring photodetector; 190-Controller; 191-Current driver; 192-Transimpedance amplifier and analog-to-digital converter circuit; 193-Temperature sensor; 200-Optical module ( Figure 5 (Shown is a coherent optical module); 210 - light source; 220 - coherent optical modulator; 230 - optical coupling structure; 240 - module control circuit; 250 - heat sink; 260 - input monitoring photodetector; 270 - protection circuit; 280 - series path voltage detection circuit. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should also be noted that, to make the embodiments more comprehensive, the following embodiments are the best and preferred embodiments, and those skilled in the art can use other alternative methods to implement some well-known technologies; moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0038] This invention provides a series-driven semiconductor optical amplifier component, optical module, and control method. The "semiconductor optical amplifier component" as used in this specification includes at least an SOA and a TEC forming a series-driven relationship. The output monitoring photodetector, input monitoring photodetector, controller, and current driver can be integrated into the component or disposed outside of it; their installation position does not affect the establishment of the series-driven electrical and thermal structure.

[0039] The term "SOA" as used in this specification refers to a semiconductor optical amplifier chip that provides gain to the input light through current injection, including traveling wave, reflective, tapered, polarization-insensitive, and other current-injection semiconductor optical amplifier chips. The input light can be continuous light, modulated light, pulsed light, or burst light.

[0040] In this specification, "series connection" means that, under main operating conditions, the same main operating current flows sequentially through the SOA and the TEC. Current sensing resistors, protective switches, current limiting components, filtering components, fuses, and connecting conductors in the main operating current path do not disrupt this series connection; high-impedance or low-power connections used for detection, communication, or protection are not used to independently establish the main drive current of the TEC. The order of the SOA and TEC in the main operating current path can be interchanged. "No independent TEC current path" means that there is no branch or current source that can independently set the high current drive current of the TEC relative to the SOA main operating current.

[0041] The main operating current can be a DC bias current or an adjustable bias current that varies with optical quantity, temperature, input light state, or preset timing. When the input light carries high-speed data modulation, the control bandwidth of the operating current can be lower than the data modulation bandwidth of the input light and it does not carry the data modulation component; for pulsed light or burst light, the operating current can also be adjusted according to the average optical power, average current, duty cycle, or burst timing.

[0042] The “complete package thermal boundary” in this specification includes at least the thermal path from the SOA junction to the TEC cold end, the internal thermal conduction between the TEC hot and cold ends, the thermal path from the TEC hot end to the package substrate or module housing, and the parasitic thermal path formed by electrodes, bonding wires, thermally conductive substrates, optical elements, package atmosphere, and radiation; under specified operating conditions, it also includes the thermal boundary between the module housing and the external heat sink or system airflow.

[0043] The term "matching" in this specification does not simply mean that the cold-end pump heat power and the cold-end heat load power are equal at a certain current point. Rather, it means that by selecting parameters, the amplitude, slope, and trend of change with ambient temperature of the two in the target operating range meet the preset junction temperature and optical performance constraints.

[0044] Example 1: Two-Power-Terminal Series Common-Drive Package Figure 1 This illustration shows one embodiment of a semiconductor optical amplifier assembly 100 and its optional output monitoring and external control relationships. The core structure of assembly 100 includes an SOA 110, a TEC 120, an optical input terminal 150, an optical output terminal 160, and a main operating current path 140. A controller 190 regulates the same operating current from the forward power terminal 141 to the return power terminal 142 via a current driver 191. The illustrated embodiment also includes an optical splitter 170, an output monitoring photodetector 180, and a transimpedance amplifier and analog-to-digital converter circuit 192; these monitoring devices can be located within assembly 100 or in an external optical module or external control optical path. Similarly, the controller 190 and the current driver 191 can be located externally to the assembly or selectively integrated within it. Figure 2A complete package thermal boundary embodiment of component 100 is shown, in which a package substrate 130 and a package housing 131 are employed; these package layers can be selected, combined, or replaced according to product structure. SOA 110 can be a traveling wave SOA, a reflective SOA, a tapered SOA, a polarization-insensitive SOA, or other current-injection semiconductor optical amplifier chip suitable as a power amplification stage, and its operating band can be O-band, C-band, L-band, or other optical communication bands.

[0045] The TEC120 can be a single-stage or multi-stage bulk material TEC, a micro TEC, a thin-film TEC, or other devices that utilize the Peltier effect for directional heat pumping. The TEC120 includes a cold end 121, a hot end 122, and a thermocouple structure 123 disposed between them. The junction region or heat-generating region 111 of the SOA110 is connected to a thermally conductive vapor chamber 112 via a chip connection layer, and the thermally conductive vapor chamber 112 is connected to the cold end 121. The hot end 122 is fixed to the package substrate 130 via a hot end connection layer. The package substrate 130 is thermally connected to the heat sink 250. Figure 2 In This represents the equivalent thermal resistance from SOA junction 111 to cold end 121. This represents the equivalent thermal resistance from the hot end 122 of the TEC to the package substrate 130 or a predetermined external heat dissipation boundary.

[0046] The thermally conductive vapor chamber substrate 112 can be made of aluminum nitride, diamond, silicon carbide, copper tungsten, copper molybdenum, or other materials that combine thermal conductivity and electrical insulation. Solder, sintered silver, thermally conductive adhesive, or a eutectic bonding layer can be used between the SOA 110 and the thermally conductive vapor chamber substrate 112. Depending on the circuit polarity requirements, the thermally conductive vapor chamber substrate 112 can also form a patterned metal layer for connecting one electrode of the SOA in series with one electrode of the TEC.

[0047] The main operating current path 140 can reach the return power terminal 142 from the forward power terminal 141 through SOA110 and TEC120. In another embodiment, the series sequence is forward power terminal 141, TEC120, SOA110, and return power terminal 142. The electrical connection polarity between SOA110 and TEC120 is configured such that when the operating current flows through the main operating current path 140 along the forward injection direction of SOA110, TEC120 pumps heat from cold end 121 to hot end 122. In a preferred two-power-terminal package, the package only provides the forward power terminal 141 and the return power terminal 142 for the main operating current path 140, without providing an additional pair of TEC high-current power terminals.

[0048] The output monitoring photodetector 180 can be encapsulated within component 100 or located in the optical module 200 or external monitoring optical path outside component 100. If the output monitoring photodetector 180 is encapsulated within the component, a separate low-power detection terminal can be provided; this detection terminal is not part of the SOA-TEC high-current path, thus significantly reducing the number of high-current power terminals. If it is required that the optical amplification package electrically only present as a pair of power terminals, the output monitoring photodetector 180 can be placed in the module optical path and read by the module control circuit.

[0049] The current driver 191 is preferably a low-ripple constant current driver. Its compliant voltage satisfies: Therefore, inserting the TEC in series will not cause optical power loop saturation due to insufficient drive voltage margin. The current driver 191 can be located on a module circuit board outside the component or integrated with the controller 190.

[0050] Example 2: Parameter Matching of Thermal Boundary in Complete Encapsulation This embodiment illustrates how to determine the combination of SOA110, TEC120 and package thermal structure during the product design phase, rather than relying solely on controller compensation after assembly.

[0051] First, at several ambient temperatures and input optical power Next, the candidate SOA was characterized by electrothermal and optical methods to obtain... , Gain Gain spectral characteristics And equivalent junction temperature data. Junction temperature can be obtained through on-chip thermistor, forward voltage drop, spectral characteristics, micro Raman spectroscopy, thermal reflectance, or calibrated thermal simulation.

[0052] Secondly, the chip interconnect layer, thermally conductive vapor chamber 112, TEC 120, hot-end interconnect layer, package substrate 130, and predetermined heat sink 250 are incorporated into a thermal model or calorimetric test to determine the parasitic heat load power. Temperature difference between hot and cold ends. For solutions with many bonding wires, optical components near the cold end, or different gas fillings inside the package, measurements or simulations should be performed separately to avoid missing non-SOA heat.

[0053] Next, the thermocouple pair number N, thermocouple arm material parameters, thermocouple arm cross-sectional area A, thermocouple arm length L, and resistance of the candidate TEC were analyzed. Thermal conductivity Effective Seebeck coefficient The cold junction area and rated current are combined. Increasing N or A / L can improve the pumping capacity in some operating ranges, but it will also change the resistance, heat return flow, and required compliance voltage. Therefore, it needs to be designed in conjunction with the SOA terminal voltage and current range.

[0054] In an optional configuration, the TEC120 includes two or more selectably connected thermocouple groups. After packaging, one group, multiple groups in series, or multiple groups in parallel can be selected via connection pads according to the measured heat load power, thereby adjusting the configuration. , and Another optional configuration includes a passive thermal bypass with a predetermined thermal conductivity between the cold end 121 and the package substrate 130. This thermal bypass introduces controlled thermal reflow to suppress overcooling under low-temperature, low-current conditions, while under high-temperature conditions, active TEC pumping heat dominates. The thermal bypass can be formed by a metal bridge, ceramic bridge, or package support with a defined cross-sectional area and length.

[0055] For each candidate combination, it can be calculated or measured. and The curve. For example... Figure 3 As shown in (a), the solid line indicates... dotted lines indicate Two thin dashed lines indicate Limited permitted bands; express In one preferred matching method, select to As a series common-drive region, The curve lies within the allowable band and makes It increases with I within this interval. The current should ideally not exceed the current corresponding to the maximum TEC pump hotspot, to prevent increased current from actually reducing cooling capacity. For example... Figure 3 As shown in (b), the output optical power can also be combined by carrier injection and junction temperature change. It increases monotonically with I within the same working range. Figure 3 The curve shape and relative position are only used to illustrate one matching result. The actual curve can be a nonlinear curve, a piecewise curve, or an intersecting curve within an allowable range. The thermal power residual and monotonicity are optional further matching criteria and do not constitute necessary conditions for the series co-drive core structure.

[0056] In addition to the cold-end thermal power residual, output optical power, gain, gain spectral peak or amplified spontaneous emission spectral peak, electro-optic efficiency, junction temperature, drive voltage requirement, and closed-loop stability margin can be jointly evaluated. For evaluation quantities with different dimensions or optimization directions, they can be normalized according to their respective allowable deviations, nominal values, or ranges, and then transformed into non-negative evaluation terms that are smaller as better. The following weighted objective function can be used: in, , , , , and These represent the normalized output optical power drift, optical gain drift, gain spectrum or output spectrum characteristic drift, electro-optic efficiency drift, junction temperature deviation, and cold-end thermal power residual, respectively. This is the normalized drive voltage requirement evaluation item; This is a non-negative penalty term constructed based on the closed-loop stability margin. Weights... to The values ​​are non-negative and determined based on product specifications. Alternatively, Pareto optimization can be used for the above evaluation quantities without pre-fixing the weights. For scenarios where the coherent optical carrier is determined by an external laser, This indicates the shift in the SOA gain peak or output spectral envelope, rather than treating the SOA as an independent laser source that determines the carrier wavelength.

[0057] For example, the target product can be set to an ambient temperature range. to The allowable operating current range of SOA is set to a sub-range from 50mA to 1.5A, and then narrowed down according to the actual chip rating. to The values ​​above are for illustrative purposes only; the specific values ​​are determined by the SOA material system, chip size, input optical power, target gain, and packaging heat dissipation conditions.

[0058] During mass production, SOA and TEC can be graded separately. SOA grading parameters can include terminal voltage, output optical power, thermal resistance, and gain temperature coefficient at a specified current; TEC grading parameters can include cold-end pump thermal power, terminal voltage, and resistance at a specified temperature difference and current. After pairing, fine-tuning is performed using the size of the thermally conductive vapor chamber substrate, the interface layer thickness, or a control lookup table to reduce matching deviations caused by device variability.

[0059] Example 3: Output Optical Power Closed Loop like Figure 1 As shown, the optical input terminal 150 receives the light to be amplified, and the SOA110 amplifies it before outputting it from the optical output terminal 160. The optical splitter 170 separates a predetermined proportion of the monitoring light from the output light and sends it to the output monitoring photodetector 180. The current generated by the output monitoring photodetector 180 is amplified by transimpedance amplification and analog-to-digital conversion circuit 192 to form a digital monitoring quantity. The corresponding closed-loop control and safety protection processes are as follows: Figure 4 As shown.

[0060] The monitored quantities are not limited to a single output optical power. Depending on the product objectives, monitoring quantities characterizing output optical power, optical gain, gain spectrum characteristics, output spectral characteristics, extinction ratio, or electro-optical efficiency can be obtained through output monitoring, combined input and output monitoring, wavelength division monitoring, or spectral monitoring, and the main operating current can be adjusted accordingly. The following uses output optical power as an example; other target optical quantities can be calculated using the same error calculation and current execution relationship.

[0061] Controller 190 stores the target output optical power And calibration coefficients. The control error can be expressed as: The controller 190 calculates the series current command for the next cycle based on the error. Taking position-type proportional-integral control as an example: in, This is the state of error integration. Limit the current to to between, This is the feedforward correction amount obtained based on the case temperature, input optical power, or target power. The feedforward only changes the initial value or command of the series current, without generating a separate TEC current; when the current command saturates or enters a protection state, it adjusts the feedforward accordingly. Perform anti-saturation treatment or freeze. Figure 4 The process includes: S101, power-on initialization, keeping the series path in a shutdown or standby state and performing a current-limiting self-test; if the self-test fails, proceed to S108; after the self-test passes, in S102, the target optical quantity, calibration parameters, safety threshold, and initial calibration value are read; in S103, the output monitoring signal and selectable input light, case temperature, and series voltage signals are read; in S104, the output optical power or gain estimate and its deviation from the target optical quantity are calculated; in S105, candidate series operating currents are calculated, and amplitude limiting, forward current limiting, rate of change limiting, and integral anti-saturation are performed; in S106, the validity of the monitoring signal, input light state, temperature, series voltage, candidate current, and continuous control deviation are judged to meet the safety conditions. If they are met, in S107, the same operating current is updated to the SOA-TEC series path, and the process returns to S103 in the next sampling cycle; if they are not met, in S108, the integral is frozen and the system enters a safe current or shutdown state. S102 is re-entered only when the recoverable fault is cleared and the conditions for retry are met; latch faults remain off until reset.

[0062] When the ambient temperature rises, causing the SOA gain to decrease... The controller increases I as the temperature drops. Since the matched TEC operates in the positive pump heat slope region, increasing I makes... The increase in temperature suppresses junction temperature; simultaneously, SOA carrier injection increases. These two effects together improve output optical power. Conversely, when low temperature or device variability leads to excessively high output optical power, the controller reduces I, decreasing both direct gain and cooling capacity to maintain consistent control direction.

[0063] This embodiment allows the SOA junction temperature to vary within a certain range without the need to set a separate junction temperature setpoint. For products requiring more stringent spectral stability, the signal from the temperature sensor 193 can be added to the objective function or feedforward table, but the stringent temperature control of the TEC does not rely on a separate TEC current channel.

[0064] Example 4: Constant Gain Control When the output power of the coherent optical modulator 220 varies with modulation format, bias state, or upstream light source power, using only constant output optical power control may mask input variations. In this embodiment, an input monitoring photodetector 260 is provided at the optical input end 150, and the input monitoring signal is used... With output monitoring signal Calculate the gain estimate: controller with The series current is used for error adjustment. For linear units, the ratio of the output to the input monitoring signal can also be used directly. The input monitoring photodetector 260 can obtain the monitoring light through a low-ratio beam splitter at the input end, or it can reuse the existing input power monitoring function in the coherent optical module.

[0065] The controller can switch between constant output optical power mode and constant gain mode. During switching, the current command remains continuous, and dI / dt is limited to avoid SOA optical output transients and TEC cold junction temperature overshoot. If the input light falls below the presence threshold, the constant output optical power loop must not continue pushing the current to the limit. Instead, it should enter standby, fixed safety gain, or shutdown state.

[0066] Example 5: State Estimation and Security Protection like Figure 6 As shown, the main operating current path 140 can be connected in series with a protection circuit 270, and a series path voltage detection circuit 280 can be set. Figure 6 In the top equation, I represents the main operating current; the voltage detection circuit 280 is connected in a high-impedance manner between the positive power terminal 141 and the return power terminal 142 to detect the total series voltage. It is not used for shunt or independent adjustment of TEC power, and therefore does not change The main series connection. The controller can estimate the TEC terminal voltage by combining the calibrated SOA voltage model: according to The temperature characteristics of the I and TEC resistors can help determine if the TEC is open-circuited, short-circuited, has poor heat dissipation at the hot end, or is an assembly abnormality. This estimation does not require a separate TEC power terminal.

[0067] Upon power-up, the controller performs a soft start from zero current or standby current, selecting initial calibration values ​​based on the case temperature and target optical power. The current rise slope is constrained by both SOA optical power overshoot and TEC thermal time constant. Since SOA typically does not allow large reverse currents, the controller does not achieve TEC heating by reversing the series current; low-temperature conditions are handled by reducing cooling capacity, utilizing SOA self-heating, and using an optional independent low-power heating element. If the low-power heating element is installed, it does not constitute an independent TEC current path for normal temperature control.

[0068] Protection conditions may include: missing input light, saturation or failure of the output monitoring photodetector, open or short circuit in the series path, insufficient driver compliance voltage, excessive case temperature or estimated junction temperature, persistently large control error after the start-up shielding period, closed-loop unreachability, long-term current saturation, and abnormal output optical power rise rate. When protection is triggered, the integrator is frozen, reduced to a safe current, or the current is cut off. Recoverable faults are reinitialized after the fault is cleared and the hysteresis and retry conditions are met. Latched faults such as open circuit, short circuit, severe overtemperature, or monitoring link failure remain off until reset.

[0069] Example 6: Optical Modules and Coherent Optical Module Examples In a general-purpose optical module implementation, the optical module includes a module optical path for the propagation of light to be amplified, a semiconductor optical amplification component 100 disposed in the module optical path, and a current driver 191 supplying power to the main operating current path 140. The semiconductor optical amplification component 100 can be disposed in a location within the module where optical path loss needs to be compensated or output power increased. The module control circuit can adjust the same operating current according to output power, input-output power ratio, spectral characteristics, or preset operating states. The core series relationship of the optical module is not limited to a specific light source, modulation format, or amplification location.

[0070] Figure 5 The coherent optical module 200 shown is a specific example of the aforementioned general optical module, including a light source 210, a coherent optical modulator 220, a semiconductor optical amplifier 100, a module control circuit 240, and a heat sink 250. The light source 210 provides continuous wave light, and the coherent optical modulator 220 modulates the light using in-phase / orthogonal and / or polarization multiplexing based on the data signal. The modulated light enters the SOA110 via the optical coupling structure 230 for post-amplification. In other optical modules, the light source 210, coherent optical modulator 220, and optical coupling structure 230 can be replaced or omitted by upstream optical units matched to the corresponding application.

[0071] The optical output terminal 160 of component 100 is equipped with an optical splitter 170. The monitoring light enters the output monitoring photodetector 180, and the main optical path outputs to the module optical interface. The module control circuit 240 executes the control algorithm of embodiment three or four, and supplies power to the SOA-TEC series path through the current driver 191. The TEC hot end 122 is thermally coupled to the module heat sink 250 through the package substrate 130.

[0072] Compared to solutions that drive the SOA and TEC separately, this embodiment eliminates the need for a separate high-current power stage of the TEC and its pair of high-current connections. The module can still retain the case temperature sensor, output monitoring photodetector, and necessary digital interfaces; these low-power detection and communication interfaces do not change the core relationship of sharing a series drive current.

[0073] This solution can also be used in incoherent optical modules, optical line amplifiers, pluggable transceiver modules, onboard optical engines, lidar source amplification stages, or optical sensing systems. The input light can be continuous wave, pulsed light, or modulated light. For pulsed or burst modes, thermal control can operate based on average current or duty cycle, and additional limits can be set for transient peak current.

[0074] Example 7: Manufacturing and Calibration Process An optional manufacturing and calibration process is as follows: The hot end 122 of the TEC120 is fixed to the packaging substrate 130; a thermally conductive vapor chamber 112 is placed on the cold end 121; the SOA110 is mounted on the thermally conductive vapor chamber 112 and optically coupled; the SOA110 and TEC120 are connected in series via metal patterns, bonding wires, or conductive connectors; the forward power terminal 141 and the return power terminal 142 are connected; after packaging, temperature scanning, current scanning, and input optical power scanning are performed under the target heat dissipation boundary; output optical power, gain, spectrum, series voltage, and selectable temperature data are obtained; based on this, the following parameters are determined: , The system generates feedforward lookup tables and closed-loop control parameters, and writes the calibration data into the non-volatile memory of the component or module.

[0075] During calibration, the assembled package and a heatsink or equivalent thermal resistance fixture representing the actual system should be used. Testing only the bare die or TEC on an open cold stage will miss package thermal reflow and hot-end temperature rise, and the resulting matching results may not be applicable to the actual module.

[0076] The thermal resistance, materials, dimensions, current, and temperature range in the above embodiments can all be adjusted according to product requirements. The semiconductor optical amplification component can employ only the aforementioned series common-drive electrical and thermal structure, or it can further employ one or more of the following: complete package thermal boundary matching, optical quantity closed-loop, feedforward control, and safety protection. Whether the output monitoring photodetector, controller, and current driver are located inside or outside the component does not change the core relationship of the SOA and TEC sharing the main operating current. Without departing from the overall inventive concept, the optional features in each embodiment can be used individually or in combination.

[0077] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0078] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A series-driven semiconductor optical amplifier component, comprising an optical input terminal (150), an optical output terminal (160), a semiconductor optical amplifier chip (110), a thermoelectric cooler (120), and a main operating current path (140), characterized in that: The semiconductor optical amplifier chip (110) is used to amplify the light entering from the optical input terminal (150) and output it from the optical output terminal (160); The semiconductor optical amplifier chip (110) and the thermoelectric cooler (120) are connected in series in the main working current path (140), so that the working current in the main working current path (140) flows through the semiconductor optical amplifier chip (110) and the thermoelectric cooler (120) in sequence. The semiconductor optical amplifier chip (110) is thermally coupled to the cold end (121) of the thermoelectric cooler (120), and the hot end (122) of the thermoelectric cooler (120) is thermally coupled to a predetermined heat dissipation boundary via a heat dissipation path. The electrical connection polarity between the semiconductor optical amplifier chip (110) and the thermoelectric cooler (120) is configured such that when the operating current flows through the main operating current path (140) along the positive injection direction of the semiconductor optical amplifier chip (110), the thermoelectric cooler (120) pumps heat from the cold end (121) to the hot end (122).

2. The semiconductor optical amplification component according to claim 1, characterized in that, The package housing the semiconductor optical amplifier chip (110) and the thermoelectric cooler (120) is provided with only one pair of power terminals for supplying power to the main operating current path (140), and no additional power terminals or power supply branches are provided to supply power to the thermoelectric cooler (120) independently of the main operating current path (140).

3. The semiconductor optical amplification component according to claim 1, characterized in that, The thermoelectric parameters of the thermoelectric cooler (120), the heat transfer parameters from the semiconductor optical amplifier chip (110) to the cold end (121), and the heat transfer parameters from the hot end (122) to the predetermined heat dissipation boundary are configured such that, within a predetermined operating current range, the increase in cold end pump heat power generated by the increase in the operating current at least partially offsets the increase in heat load power transferred from the semiconductor optical amplifier chip (110) to the cold end (121).

4. The semiconductor optical amplification component according to claim 3, characterized in that, Within a target operating domain defined by a predetermined operating current range, predetermined input light conditions, predetermined ambient temperature range, and predetermined external heat dissipation conditions, and under the package thermal boundary including the chip interconnect structure, the thermoelectric cooler (120), the package substrate, and parasitic heat paths, the cold-end pumping heat power of the thermoelectric cooler (120) is... and the cold-end heat load power of the cold-end system where the semiconductor optical amplifier chip (110) is located. Determined by the following formula: Wherein, I is the operating current, and the positive direction is the direction in which the semiconductor optical amplifier chip (110) is injected in the forward direction and the thermoelectric cooler (120) pumps heat from the cold end (121) to the hot end (122); The cold end temperature is expressed in absolute temperature. This refers to the hot end temperature. The junction temperature of the semiconductor optical amplifier chip (110) is... For ambient temperature, The equivalent Seebeck coefficient, The equivalent resistance of the thermoelectric cooler (120) is... The equivalent thermal conductivity of the thermoelectric cooler (120) is... The terminal voltage of the semiconductor optical amplifier chip (110) is... It is the difference between the total optical power output outward through the optical boundary of the cold-end system, including signal light and amplified spontaneous emission, and the total optical power input through the optical boundary. The parasitic heat load power is defined with the flow into the cold-end system as the positive direction; within the target operating domain, each candidate operating point is determined according to a preset cold-end temperature or a preset junction temperature, satisfying... Not greater than the preset thermal power tolerance.

5. The semiconductor optical amplification component according to claim 3, characterized in that, The predetermined operating current range includes at least one continuous effective operating current segment; under given input light conditions and external heat dissipation boundary conditions, the cold end pumping thermal power of the thermoelectric cooler (120) increases with the increase of the operating current within the continuous effective operating current segment; and, after considering the direct influence of the operating current on carrier injection and the indirect influence caused by junction temperature changes, the steady-state output optical power of the semiconductor optical amplifier chip (110) increases with the increase of the operating current within the continuous effective operating current segment.

6. The semiconductor optical amplification component according to claim 1, characterized in that, The semiconductor optical amplifier chip (110) is thermally coupled to the cold end (121) through a chip connection layer, or thermally coupled to the cold end (121) in sequence through a chip connection layer and a thermally conductive heat dissipation structure (112); the hot end (122) is thermally connected to the packaging substrate (130) through a hot end connection layer, and the packaging substrate (130) is configured to be thermally connected to at least one of the component housing, the optical module housing and the external heat sink.

7. The semiconductor optical amplification component according to claim 3, characterized in that, The thermoelectric cooler (120) is configured to at least one of the following: the number of thermocouple pairs, thermoelectric arm material, the ratio of thermoelectric arm cross-sectional area to length, equivalent resistance, equivalent thermal conductivity, cold end area, and rated current; and at least one of the following: chip connection layer thermal resistance, area or thickness of thermally conductive heat dissipation structure, hot end connection layer thermal resistance, package substrate thermal resistance, passive thermal bypass thermal conductivity, and equivalent heat dissipation thermal resistance of a predetermined external heat dissipation boundary. This is configured to at least partially compensate for the change in thermal load power transferred from the semiconductor optical amplifier chip (110) to the cold end (121) as the operating current changes, thereby suppressing the junction temperature change of the semiconductor optical amplifier chip (110).

8. A control method for a series-driven semiconductor optical amplifier assembly, characterized in that, include: To acquire monitoring quantities that characterize the amplified output light state of a semiconductor optical amplifier chip; The series operating current is determined based on the deviation between the monitored quantity and the preset target optical quantity; The series operating current is applied in the direction that allows the semiconductor optical amplifier chip to be injected in the forward direction to the operating current path formed by the semiconductor optical amplifier chip and the thermoelectric cooler connected in series. This allows the same series operating current to inject charge carriers into the semiconductor optical amplifier chip while simultaneously driving the thermoelectric cooler to pump heat from the cold end, which is thermally coupled to the semiconductor optical amplifier chip, to the hot end. The series operating current is adjusted based on the subsequently acquired monitoring data.

9. The control method according to claim 8, characterized in that, The series operating current is limited between a predetermined minimum current and a predetermined maximum current, wherein the predetermined maximum current does not exceed the allowable forward current of the semiconductor optical amplifier chip and does not exceed the allowable operating current of the thermoelectric cooler under predetermined operating conditions; an integral anti-saturation parameter is set according to the predetermined minimum current and the predetermined maximum current, and a rate of change limit or thermal compensation filter parameter for the series operating current is set according to the thermal time constant of the thermoelectric cooler and the encapsulated thermal network.

10. An optical module, comprising a module optical path, a semiconductor optical amplifier chip (110), a thermoelectric cooler (120), a current driver (191), and a module heat dissipation path, characterized in that: The semiconductor optical amplifier chip (110) is disposed in the module optical path and is used to amplify the light transmitted along the module optical path; The semiconductor optical amplifier chip (110) is thermally coupled to the cold end (121) of the thermoelectric cooler (120), and the hot end (122) of the thermoelectric cooler (120) is thermally coupled to the heat dissipation boundary of the module through the module heat dissipation path; The semiconductor optical amplifier chip (110) and the thermoelectric cooler (120) are connected in series to form a series working current path and are connected to the current driver (191), so that the same working current output by the current driver (191) flows through the semiconductor optical amplifier chip (110) and the thermoelectric cooler (120). The electrical connection polarity between the semiconductor optical amplifier chip (110) and the thermoelectric cooler (120) is configured such that when the operating current flows along the positive injection direction of the semiconductor optical amplifier chip (110), the thermoelectric cooler (120) pumps heat from the cold end (121) to the hot end (122).

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