Wavelength selection method based on glass substrate optical waveguide external cavity large-scale chip system

Abstract

This invention relates to the field of optical communication technology, specifically to a wavelength selection method for a large-range chip system based on a glass substrate optical waveguide external cavity. The chip system includes a glass substrate optical waveguide chip and a gain chip. The dual-tuning module includes a dual-tuning unit, a beam splitting unit, a wavelength selection unit, and a beam splitting monitoring unit. The dual-tuning unit includes a non-volatile modulation section and a phase dynamic tuning section. The wavelength selection unit includes a wavelength non-volatile modulation section and a wavelength dynamic tuning section. The method includes: the beam splitting monitoring unit splits the output light into a working output light and a monitoring output light, and monitors the wavelength offset deviation of the monitoring output light; configuring a corresponding wavelength tuning mode for the dual-tuning module based on the wavelength offset deviation; then monitoring the output light of the laser and performing closed-loop feedback, and modulating multiple times until the wavelength meets the target value before outputting. This method can reduce initial phase modulation power consumption and modulate the phase and wavelength in real time, keeping the output light power at its maximum.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, and in particular to a wavelength selection method for a wide-range chip system based on a glass substrate optical waveguide external cavity. Background Technology

[0002] In recent years, with the increasing demand for network applications, especially the rapid development of high-definition video and high-speed data services, the demand for network bandwidth has been increasing. Existing communication systems are evolving towards 100Gbit / s, or even higher speeds of 400Gbit / s. High-speed tunable lasers with a wide range of wavelengths are widely used in fields such as high-speed optical communication, lidar, and long-distance sensing. However, high-speed coherent communication systems place demands on tunable lasers with characteristics such as wide tuning range, high frequency stability, narrow linewidth, high power, low power consumption, and small size.

[0003] In dense wavelength division multiplexing (DWDM) systems, tunable lasers can replace multiple fixed-wavelength lasers, significantly reducing the cost of backup light sources and providing timely and effective inventory management and rapid channel establishment. In next-generation reconfigurable optical networks, tunable lasers can also provide automatic wavelength configuration, wavelength conversion, and wavelength routing, thereby increasing network flexibility and bandwidth utilization. In recent decades, tunable lasers have received widespread attention and research both domestically and internationally.

[0004] Existing tunable lasers include commercially available tunable distributed feedback (DFB) laser arrays, including temperature-tunable DFB laser arrays, and distributed reflection (DBR) type tunable lasers that utilize the electro-optic effect generated by injected current for tuning. These lasers achieve high-speed wavelength tuning by selecting different wavelengths through electro-optic switching. However, the tuning range of this approach is limited by the number of channels in the laser array, and the linewidth is only in the megahertz (MHz) range. DFB laser arrays are developed based on single DFB lasers. Due to temperature tuning, the tuning range of a single DFB laser is typically only 3 to 5 nm.

[0005] Furthermore, on-chip external cavity lasers, based on the vernier effect, utilize a reflective semiconductor optical amplifier coupled with a cascaded micro-ring external cavity. The composite cavity operates within an equivalent single passband within its gain bandwidth, achieving single-mode output. The thermo-optical modulation vernier external cavity allows for different wavelength selection, enabling wide-range wavelength tuning of the laser, reaching up to 100 nm, with intrinsic linewidths typically in the range of 1 kHz to 100 kHz. However, thermo-optical modulation of the cascaded micro-ring external cavity suffers from thermal crosstalk, making wavelength tuning difficult to control. Moreover, the thermo-optical modulation rate is low, making it difficult to achieve wavelength switching within 10 μs. This cannot meet the requirements of some lidar beam scanning and optical wavelength routing applications.

[0006] In recent years, glass-substrate integrated photonics technology has attracted attention due to its advantages such as ultra-low thermo-optic coefficient (1-2 orders of magnitude lower than silicon), low transmission loss, and wide transparency window, which are expected to reduce thermal crosstalk and improve wavelength stability. Meanwhile, phase change materials (PCMs) can achieve non-volatile optical tuning through reversible phase transitions between crystalline and amorphous states induced by electrical pulses—maintaining the state without continuous power supply after the phase transition, significantly reducing static power consumption, and achieving response speeds in the microsecond to nanosecond range. However, PCM tuning suffers from limited cycle durability and relatively high insertion loss, requiring its use in conjunction with other tuning mechanisms.

[0007] The main shortcomings of existing solutions are: (1) slow thermo-optical tuning response and high power consumption, and limited tuning range of electro-optical tuning solutions; (2) serious crosstalk between silicon-based thermo-optical systems and poor wavelength stability; (3) lack of non-volatile tuning capability, high standby power consumption and loss of state after power failure; (4) difficulty in balancing integration and performance. Therefore, there is an urgent need for a light source solution that combines narrow linewidth, high frequency modulation linearity, non-volatile tuning, low power consumption and high integration.

[0008] Chinese patent document CN117498135A discloses a wide-range wavelength tunable laser, including a semiconductor optical amplifier (SOA) chip. The two ends of the SOA chip are coupled to the edges of a first micro-ring resonator and a second micro-ring resonator, respectively. The coupled portions are each coated with at least one anti-reflection film (AR). An internal gain dielectric waveguide is arranged along the cavity. The second micro-ring resonator also includes a thermoelectric electrode to achieve wide-range wavelength tuning. The first micro-ring resonator also includes a piezoelectric ceramic electrode to achieve high-speed wavelength switching. The external cavity laser based on the semiconductor optical amplifier of this invention, particularly a hybrid integrated wide-range wavelength tunable high-speed tunable laser, can achieve both wide-range wavelength tuning and rapid wavelength switching. However, this prior art uses a silicon substrate, which has high thermal conductivity. Heating one ring heater will conduct heat to another resonator, resulting in severe thermal crosstalk between the rings, which causes the resonant frequencies to shift. Furthermore, it can only complete a 20nm full-band scan requiring hundreds of milliseconds, and the wide-range wavelength switching speed cannot meet the requirements of high-speed routing and high-speed frequency-sweeping lidar.

[0009] Furthermore, commonly used technologies include directly modulated DFB / DBR / SG-DBR lasers and silicon-based silicon / silicon nitride / silicon oxynitride / lithium niobate waveguide microring external cavity tunable lasers. When relying directly on thermal tuning, continuous heating is required to maintain the operating point, resulting in high static power consumption, and temperature disturbances can cause wavelength drift. While silicon substrate-based external cavity structures can achieve on-chip integration, the substrate has a high coefficient of thermal expansion, leading to low temperature stability. Moreover, waveguide external cavities typically exhibit initial emission wavelength deviations due to process variations such as waveguide width and etching depth; most existing correction methods rely on screening or continuous thermal tuning, making long-term compensation under low power consumption conditions difficult. Summary of the Invention

[0010] The purpose of this invention is to provide a wavelength selection method for a wide-range chip system based on a glass substrate optical waveguide external cavity. By using a low thermal expansion glass substrate, mechanical stress and optical path drift caused by packaging and environmental temperature changes are reduced, which can improve the temperature stability of the external cavity and is more conducive to the long-term stability of the device. The long selection method using dual-tuning modules can reduce the initial phase modulation power consumption and modulate the phase and wavelength in real time to keep the output light power at its maximum.

[0011] To solve the aforementioned technical problems, the present invention specifically adopts the following technical solution: This invention provides a wavelength selection method for a wide-range chip system based on a glass substrate optical waveguide external cavity, the chip system comprising: Glass substrate optical waveguide chip; Gain chip, used to provide broadband optical; A dual-tuning module includes: a dual-tuning unit, a beam splitting unit, and at least two wavelength selection units arranged sequentially on a glass substrate optical waveguide chip, wherein the beam splitting unit and the wavelength selection units together constitute a Sagnac resonant cavity, and the dual-tuning unit is coupled to the Sagnac resonant cavity; a beam splitting monitoring unit is provided at one output end of the beam splitting unit. The dual-tuning unit includes a non-volatile modulation section and a phase dynamic tuning section. The wavelength selection unit includes: a wavelength non-volatile modulation section and a wavelength dynamic tuning section; Both the non-volatile modulation section and the wavelength non-volatile modulation section include a phase change material. The non-volatile modulation section or the wavelength non-volatile modulation section modulates the phase change material by means of optical pulses, electrical pulses or thermal excitation, so that the phase change material is in a crystalline or amorphous state. Both the phase dynamic tuning section and the wavelength dynamic tuning section change the wavelength of the output light by heating the optical waveguide and adjusting the resonance conditions. Correspondingly, the method includes: The beam splitting monitoring unit divides the output light into working output light and monitoring output light, and monitors the wavelength offset deviation of the monitoring output light. Based on the wavelength offset deviation, the corresponding wavelength tuning mode is configured for the dual tuning module. Then, the output light of the laser is monitored and feedback is closed, and the light is modulated multiple times until the wavelength meets the target value before output. The steps for configuring the corresponding wavelength tuning mode for the dual-tuning module based on the wavelength offset deviation include: When the wavelength offset deviation is less than the set wavelength offset deviation threshold, the first wavelength selection tuning mode is activated. The first wavelength selection tuning mode is: the wavelength non-volatile modulation unit maintains the initial default state and the wavelength dynamic tuning unit is called to perform wavelength modulation. When the wavelength offset deviation is greater than or equal to the set wavelength offset deviation threshold, the second wavelength selection tuning mode is activated. The second wavelength selection tuning mode is as follows: the wavelength non-volatile modulation unit performs wavelength modulation in the first wavelength range, and the wavelength dynamic tuning unit performs wavelength modulation in the second wavelength range.

[0012] Preferably, the step of monitoring the output light of the laser and performing closed-loop feedback includes: The power of the laser output light is monitored in real time to obtain the power offset deviation; based on the power offset deviation, the corresponding phase tuning mode is configured for the dual-tuning module, and the phase is modulated in real time by the dual-tuning unit to maintain the maximum power of the output light; specifically: When the power offset deviation is less than the set power offset deviation threshold, the first phase tuning mode is activated; when the power offset deviation is greater than or equal to the set power offset deviation threshold, the second phase tuning mode is activated.

[0013] Preferably, when the second wavelength selection tuning mode is activated, the following steps are performed: The modulation range of the wavelength dynamic tuning unit or the phase dynamic tuning unit is limited according to a preset priority rule. The priority rule is as follows: both the dual tuning unit and the wavelength selection unit are set with different priority levels. When the priority level is greater than the set priority threshold, the modulation range of the corresponding dual tuning unit or wavelength selection unit will be limited.

[0014] Preferably, when the second wavelength selection tuning mode is activated, the method further includes the following steps: The system acquires the current operational risk of the chip system and generates a priority threshold based on the current operational risk. It then selects dual-tuning units or wavelength selection units with a priority level greater than the priority threshold and limits the modulation range of their corresponding phase dynamic tuning units or wavelength dynamic tuning units.

[0015] Preferably, the two wavelength selection units are a first wavelength selection unit and a second wavelength selection unit, both of which are micro-ring filter cavities, and the micro-ring diameter of the first wavelength selection unit is larger than that of the second wavelength selection unit.

[0016] Preferably, when the second wavelength selection tuning mode is activated, the method further includes the following steps: If the operational risk is greater than the preset first risk threshold and less than or equal to the second risk threshold, and the application scenario prioritizes communication maintenance, then the second wavelength selection unit has the highest priority, followed by the first wavelength selection unit. In this case, the modulation range of the wavelength dynamic tuning unit is restricted first.

[0017] Preferably, when the second wavelength selection tuning mode is activated, the method further includes the step of limiting the modulation range of the phase dynamic tuning unit if the operating risk is greater than a preset second risk threshold.

[0018] Preferably, when the second wavelength selection tuning mode is activated, the method further includes the following steps: if the operating risk is greater than a preset first risk threshold and less than or equal to a second risk threshold, and the application scenario prioritizes phase accuracy or linearity, then the dual tuning unit has the highest priority, and the first wavelength selection unit has the next highest priority. In this case, the modulation range of the phase dynamic tuning unit is limited first.

[0019] Preferably, when the second wavelength selection tuning mode is activated, the method further includes the step of limiting the modulation range of the wavelength dynamic tuning unit if the operating risk is greater than a preset second risk threshold.

[0020] Preferably, the beam splitting unit adopts a beam splitting ratio tunable MZI structure, and one arm of the beam splitting ratio tunable MZI structure includes a second non-volatile modulation section for modulating the phase.

[0021] Beneficial technical effects: (1) Compared with the scheme that relies solely on the internal thermal tuning of DFB or DBR chips, the present invention moves the wavelength selection unit and the dual tuning unit with compensation capability to the glass substrate external cavity side, which can utilize the longer equivalent cavity length and more flexible filtering structure to obtain stronger mode selection and narrow linewidth potential.

[0022] (2) Compared with the silicon substrate external cavity scheme, the present invention uses a low thermal expansion glass substrate, which reduces mechanical stress and optical path drift caused by packaging and environmental temperature changes, and is more conducive to the long-term stability of the device.

[0023] (3) Compared with the pure thermal tuning external cavity scheme, the present invention uses PCM phase change material for non-volatile coarse adjustment compensation, which can remember the calibration state without long-term high-power heating, reduce static power consumption, and improve the factory sorting and refitting capabilities.

[0024] (4) The present invention takes into account both device-level performance and packaging-level manufacturability. The nanoimprint waveguide platform is suitable for mass production, and the glass platform is suitable as an independent external cavity chip, board-level optical path or package intermediary layer, thus having both performance and cost reduction potential.

[0025] (5) The matching wavelength selection method realizes real-time modulation of phase and wavelength, so that the output light power is kept to the maximum. At the same time, the dual tuning module forms a layered and rate-separated tuning mechanism for PCM non-volatile coarse tuning heating or electrical fine tuning, and can avoid overcurrent and overheating in the phase region, thus extending the life of the chip. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. The elements or parts in the drawings are not necessarily drawn to scale. Obviously, the drawings described below are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0027] Figure 1 This is a schematic diagram of the architecture of a large-scale chip system based on a glass substrate optical waveguide external cavity. Figure 2 This is a schematic cross-sectional view of a large-scale chip system based on a glass substrate optical waveguide external cavity. Figure 3 This is a schematic diagram of the optical path of a large-scale chip system based on a glass substrate optical waveguide external cavity. Figure 4 This is a flowchart illustrating a wavelength selection method for a wide-range chip system based on a glass substrate optical waveguide external cavity. Figure 5 This is a schematic diagram of the closed-loop feedback process for monitoring laser output in a wavelength selection method for a large-scale chip system based on a glass substrate optical waveguide external cavity. Summary of attached labeling and identification: 100-Glass substrate optical waveguide chip; 101-Glass substrate; 102-Optical waveguide layer; 103-Upper cladding layer; 104-PCM phase change material layer; 105-Beam splitting monitoring unit; 200-gain chip; 300 - Dual-tuning unit; 301 - Non-volatile modulation section; 302 - Phase dynamic tuning section; 400 - Wavelength selection unit; 401 - First wavelength non-volatile modulation unit; 402 - First dynamic tuning unit; 403 - Second wavelength non-volatile modulation unit; 404 - Second dynamic tuning unit; 500 - Beam splitter unit; 501 - Second non-volatile modulation unit; O1 - First output monitoring terminal; O2 - Second output monitoring terminal; O3 - Third output monitoring terminal; O4 - Fourth output monitoring terminal; O5 - Laser output terminal; I - First transmission waveguide; I1 - First output waveguide; I2 - Second output waveguide; II - Second transmission waveguide; II1 - Third output waveguide; II2 - Working output waveguide; III - U-shaped waveguide; R1 - First optical path; R2 - Second optical path. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] In this document, suffixes such as "module," "part," or "unit" used to denote elements are used only for the purpose of illustrative purposes and have no specific meaning in themselves. Therefore, "module," "part," or "unit" may be used interchangeably.

[0030] In this document, the terms "upper," "lower," "inner," "outer," "front," "rear," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] In this document, "and / or" includes any and all combinations of one or more of the listed related items.

[0032] In this article, "multiple" means two or more, that is, it includes two, three, four, five, etc.

[0033] Definition of noun: Non-volatile modulation section, first wavelength non-volatile modulation section, second wavelength non-volatile modulation section, second non-volatile modulation section: also refers to PCM phase change tuning unit or PCM phase change material or PCM.

[0034] In this specification, "large range" in a glass substrate optical waveguide external cavity large range chip system refers to a tuning range of >10nm and an intrinsic linewidth typically in the range of 1kHz to 100kHz.

[0035] Example 1: The wavelength selection method for this glass substrate optical waveguide external cavity large-range chip system, see [link to example]. Figure 1 The chip system includes: Glass substrate optical waveguide chip 100; Gain chip 200 is used to provide broadband light; the coupling between glass substrate optical waveguide chip 100 and gain chip 200 can be end-face coupling, evanescent coupling, vertical coupling, lens-assisted coupling, or intermediate transition waveguide coupling. The gain unit in gain chip 200 can be DFB, DBR, SOA with external cavity, ROSA emitter chip, or other semiconductor gain devices; The dual-tuning module includes: a dual-tuning unit 300, a beam splitting unit 500, and at least two wavelength selection units 400 arranged sequentially on a glass substrate optical waveguide chip 100. The beam splitting unit 500 and the wavelength selection units 400 together constitute a Sagnac resonant cavity, and the dual-tuning unit 300 is coupled to the Sagnac resonant cavity. A beam splitting monitoring unit 105 is provided at one output terminal of the beam splitting unit 500. The dual-tuning unit 300 includes a non-volatile modulation unit 301 and a phase dynamic tuning unit 302. The wavelength selection unit 400 includes: a wavelength non-volatile modulation section and a wavelength dynamic tuning section; In this embodiment, the dual-tuning module includes two wavelength selection units 400, namely a first wavelength selection unit and a second wavelength selection unit. The first wavelength selection unit includes a first wavelength non-volatile modulation section 401 and a first dynamic tuning section 402, and the second wavelength selection unit includes a second wavelength non-volatile modulation section 403 and a second dynamic tuning section 404. Both the first and second wavelength selection units are micro-rings, and the diameter of the micro-ring of the first wavelength selection unit is larger than the diameter of the micro-ring of the second wavelength selection unit. By setting two or more wavelength selection units 400, a narrow linewidth and wide-range wavelength tuning function can be realized. Correspondingly, the wavelength non-volatile modulation sections are the first wavelength non-volatile modulation section 401 and the second wavelength non-volatile modulation section 403, and the wavelength dynamic tuning sections are the first dynamic tuning section 402 and the second dynamic tuning section 404.

[0036] In some specific embodiments, the wavelength selection unit 400 may be a Bragg grating, a Vernier structure, a Fabry-Perot interference filter, a Sagnac reflector, etc.

[0037] In some specific embodiments, the dual-tuning module may also include three or more wavelength selection units 400 (micro-rings).

[0038] In some specific embodiments, the dual-tuning module may also include one or more MZI interferometers and multiple wavelength selection units 400 composed of one or more MZI interferometers cascaded with microrings.

[0039] Both the phase dynamic tuning unit 302 and the wavelength dynamic tuning unit change the wavelength of the output light by heating the optical waveguide and adjusting the resonance conditions. The beam splitting unit 500 adopts a beam splitting ratio tunable MZI structure. One arm of the beam splitting ratio tunable MZI structure includes a second non-volatile modulation section 501 for modulating the phase, which plays the function of tuning the beam splitting ratio. The non-volatile modulation unit 301, the first wavelength non-volatile modulation unit 401, the second wavelength non-volatile modulation unit 403, and the second non-volatile modulation unit 501 mentioned above all include phase change materials. The non-volatile modulation unit 301 or the wavelength non-volatile modulation unit modulates the phase change material by means of optical pulses, electrical pulses, or thermal excitation, so that the phase change material is in a crystalline or amorphous state.

[0040] See Figure 2 The glass substrate optical waveguide chip 100 includes a glass substrate 101 and an optical waveguide layer 102, the optical waveguide layer 102 being disposed on the surface of the glass substrate 101; it also includes an upper cladding layer 103, the upper cladding layer 103 being disposed on the glass substrate 101 and covering the optical waveguide layer 102; a PCM phase change material layer 104 is disposed on the upper cladding layer 103.

[0041] The PCM phase change material layer 104 here can be a non-volatile modulation section 301 or / and a wavelength non-volatile modulation section or / and a second non-volatile modulation section 501. The non-volatile modulation section 301 or / and the wavelength non-volatile modulation section or / and the second non-volatile modulation section 501 are disposed in the effective optical path sensitive region of the external cavity.

[0042] In this embodiment, the wavelength selection unit 400 and the dual-tuning unit 300 with compensation capability are moved to the external cavity side of the glass substrate optical waveguide chip 100. That is, a low-loss waveguide external cavity and its wavelength selection unit 400 formed by nanoimprinting such as SiON, Si3N4 or Ta2O5 are used. At the same time, a PCM phase change material layer 104 is integrated in the sensitive optical path region of the external cavity for non-volatile compensation of the initial emission wavelength deviation. The PCM phase change material layer 104 can be arranged at different positions such as the external cavity phase shifter, the micro-ring coupling region, and the micro-ring phase shift region, thereby forming a non-volatile modulation section 301 or / and a first wavelength non-volatile modulation section 401 or / and a second wavelength non-volatile modulation section 403 or / and a second non-volatile modulation section 501.

[0043] In some specific embodiments, the glass substrate 101 is a low thermal expansion glass, such as borosilicate glass, aluminosilicate glass, fused silica, or other glass materials with low thermal drift characteristics. The optical waveguide layer 102 is a single layer of silicon nitride, silicon oxynitride, tantalum oxide, or a composite multilayer of one or more of the above materials. The upper cladding layer 103 is silicon oxide. The PCM phase change material in the PCM phase change material layer 104 can be selected from GST, GSST, Sb2S3, and Sb2Se3-based phase change optical materials. The phase dynamic tuning section 302, the first dynamic tuning section 402, and the second dynamic tuning section 404 above the glass substrate optical waveguide chip 100 can all be modulation layer materials, such as lithium niobate, lithium tantalate, electro-optic polymers, BTO, PZT, and other optical materials with Pockels electro-optic effects.

[0044] In some specific embodiments, the PCM phase change material layer 104 can be arranged in the phase segment, coupling segment, filtering segment, reflection segment, or monitoring branch. The PCM phase change material can also be an amorphous-crystalline reversible material with low optical loss (low loss is a property of the material system; for example, some chalcogenide PCM materials (Sb2S3) have the ability to be optically low-loss amorphous-crystalline bidirectionally reversible). A multi-level programming strategy can also be adopted. By writing or erasing the phase state of the PCM phase change material once or multiple times through the programming electrode, its refractive index and / or absorption coefficient are controllably changed, thereby changing the equivalent optical path of the external cavity, the position of the resonance peak, or the feedback phase, which is used to compensate for the initial wavelength deviation and set the coarse adjustment operating point.

[0045] In addition to the coarse tuning performed by the non-volatile modulation unit 301 using PCM phase change material, a fine or high-speed tuning unit (phase dynamic tuning unit 302) is also provided. The phase dynamic tuning unit 302 can be a micro-heater or an electro-optic modulation section (for fine tuning via heating or electro-tuning) used to perform continuous scanning within a small range near the compensated coarse tuning operating point, thereby achieving channel alignment and high-speed tuning. Thus, the fine tuning by the phase dynamic tuning unit 302 and the coarse tuning by the non-volatile modulation unit 301 form a layered, rate-based dual tuning mechanism.

[0046] Correspondingly, the first wavelength selection unit and the second wavelength selection unit also form a dual-tuning mechanism.

[0047] The chip system also includes a first output monitoring terminal O1, a second output monitoring terminal O2, a third output monitoring terminal O3, and a fourth output monitoring terminal O4. Since the optical signal ultimately used is the laser output optical signal, the main purpose of the four output monitoring terminals is to monitor its operating status (for example, it can be used for chip testing and screening, and for pre-shipment verification. For example, when given a specific range of light waves and using given operating parameters, the four output monitoring terminals should have specific output values).

[0048] See Figure 3 The gain chip 200 (RSOA) outputs light, which is then split into two paths after reaching the beam splitter unit 500, namely the first optical path R1 ( Figure 3 (Solid line arrow direction) and second optical path R2 ( Figure 3 (In the direction of the dashed arrow in the middle), specifically, the first optical path R1 passes through the first wavelength selection unit and the second wavelength selection unit clockwise; the second optical path R2 passes through the second wavelength selection unit and the first wavelength selection unit counterclockwise.

[0049] Specifically, a first transmission waveguide I is provided at the output end of the gain chip 200. A non-volatile modulation section 301 and a phase dynamic tuning section 302 are first provided on the transmission waveguide to form a dual tuning unit 300.

[0050] Subsequently, a second non-volatile modulation unit 501 is provided along the optical path transmission direction on the first transmission waveguide I. At this time, a second transmission waveguide II is provided at a position adjacent to the first transmission waveguide I, and the first transmission waveguide I, the second transmission waveguide II, and the second non-volatile modulation unit 501 correspond to form a beam splitting unit 500 (it can be understood that the second transmission waveguide II can split part of the light from the first transmission waveguide I through coupling, thus playing a beam splitting role).

[0051] Subsequently, a first output waveguide I1 (equivalent to an extension of the first transmission waveguide I) and a second output waveguide I2 (equivalent to an extension of the second transmission waveguide II) extend from the first output end of the beam splitter 500. Their output ends are respectively regarded as the fourth output monitoring end O4 and the first output monitoring end O1. A U-shaped waveguide III is arranged between the first output waveguide I1 and the second output waveguide I2, and the two output ends of the U-shaped waveguide III are also arranged along the direction of the first output waveguide I1 and the second output waveguide I2. The two output ends that are close to the fourth output monitoring end O4 and the first output monitoring end O1 are respectively regarded as the third output monitoring end O3 and the second output monitoring end O2. A first micro-ring (with a first wavelength non-volatile modulation section 401 and a first dynamic tuning section 402) is arranged between the first output waveguide I1 and the U-shaped waveguide III, and a second micro-ring (with a second wavelength non-volatile modulation section 403 and a second dynamic tuning section 404) is arranged between the second output waveguide I2 and the U-shaped waveguide III. Thus, the first output waveguide I1, the first micro-ring, the U-shaped waveguide III, the second micro-ring, and the second output waveguide I2 arranged in sequence form a wavelength selection unit 400.

[0052] Furthermore, a third output waveguide II1 (equivalent to an extension of the second transmission waveguide II in another direction) extends from the second output end of the beam splitter 500. This third output waveguide outputs the final result processed by the beam splitter 500 and the wavelength selection unit 400. In order to monitor the reliability of the output result, a monitoring waveguide (equivalent to a beam splitter monitoring unit 105) is also provided on the third output waveguide II1. By monitoring the wavelength of the light output by the monitoring waveguide, the deviation between the output wavelength and the target wavelength can be evaluated.

[0053] Specifically, the third output waveguide II1 is divided into a monitoring waveguide and a working output waveguide II2 from the laser output terminal O5.

[0054] Each microring has a comb-shaped transmission spectrum with different FSRs or comb tooth spacing, forming a Vernier vernier effect filter. The first optical path R1 and the second optical path R2 pass through the beam splitter 500 again for beam combining interference. Part of the output is sent to the working output waveguide II2, and the other part is reflected back to the gain chip 200 (RSOA). The beam splitter 500 and the wavelength selection unit 400 essentially constitute a semi-transparent and semi-reflective wavelength selective reflector (i.e., the beam splitter 500 and the wavelength selection unit 400 together form a Sagnac resonant cavity); and form a resonant cavity with the internal reflector of the gain chip 200 (RSOA); and the internal optical path of the resonant cavity is tuned by the dual tuning unit 300 so that the target wavelength meets the coherent constructive condition and achieves maximum lasing output.

[0055] Example 2: See Figure 4 The tuning method for the dual-tuning module corresponding to Embodiment 1 includes: S101, monitors the tuning index deviation of the input light and / or output light; the input light here is the output light of the gain chip 200 (RSOA), and the output light is the tuned light (which can be the light output of the monitoring waveguide). S102, Configure the corresponding phase tuning mode for the dual tuning module according to the light tuning index deviation; The specific steps for configuring the phase tuning mode in step S102 include step S1021: When the index deviation is less than the set deviation threshold, the first phase tuning mode is activated. The first phase tuning mode is: the non-volatile modulation unit 301 maintains the initial default state and calls the phase dynamic tuning unit 302 to perform phase modulation. When the index deviation is greater than or equal to the set deviation threshold, the second phase tuning mode is activated. The second phase tuning mode is as follows: the non-volatile modulation unit 301 performs phase modulation of the first phase range (coarse tuning, i.e., factory modulation; or initial wavelength calibration after packaging), and the phase dynamic tuning unit 302 performs phase modulation of the second phase range (i.e., fine tuning by the thermal phase shifter). Furthermore, the heat generated by the phase dynamic tuning unit 302 performing phase tuning within the second phase range is less than the set heat value. In step S102, the wavelength deviation threshold is set to 5 pm; the absolute value of the wavelength deviation is < 5 pm. The specific method for measuring the on-chip wavelength is usually through an unequal-arm MZI structure, and the wavelength change is determined based on the change in its output power.

[0056] Considering the different purposes of coarse and fine adjustment settings for the non-volatile modulation unit 301 and the phase dynamic tuning unit 302, engineers can assign different phase modulation ranges at the factory. Furthermore, during actual operation, the size of each phase modulation range can be dynamically adjusted. In this embodiment, the tuning index deviation can refer to the size of the phase range to be modulated, i.e., the phase difference between the input light and the output light; or it can refer to the deviation of the phase difference to be modulated. In other words, there is an inherent phase difference between the input light and the output light, and this difference is the phase range to be modulated by the device, which is the size of the phase range to be modulated. This phase range size can be used as the tuning index deviation for tuning mode configuration. Simultaneously, during actual operation, the difference between the target phase value to be modulated and the actual output phase value, i.e., the deviation of the actual phase difference from the target phase difference, reflects the control accuracy. This deviation size can also be used as the tuning index deviation for tuning mode configuration.

[0057] Step S102 includes: S1022, monitoring the ambient temperature of the chip system and performing phase modulation based on the ambient temperature, specifically: When the ambient temperature is higher than the set temperature threshold, the set heat score will be reduced. When the ambient temperature is lower than or equal to the set temperature threshold, the set heat score is increased.

[0058] Typically, a TEC (Thermal Control Unit) temperature controller is placed on the bottom of the chip to measure the on-chip temperature in real time and control the TEC heating / cooling power to keep the chip at a constant temperature. In this embodiment, the heat score is used as a metric to measure the amount of heat generated by the phase dynamic tuning unit 302. It is understood that since the phase dynamic tuning unit 302 relies on temperature management for phase adjustment, when it needs to operate at slightly higher temperatures (such as 40°C, 45°C, or 50°C), which are often higher than the ambient temperature, heat accumulation is more likely, potentially leading to localized overheating over prolonged operation. The ambient temperature threshold is set between 50°C and 70°C. When the ambient temperature exceeds the threshold, the set heat score is reduced, limiting the degree of thermo-optical modulation and decreasing the operation of the phase dynamic tuning unit 302, thereby reducing heat generation.

[0059] Therefore, in this embodiment, a heat score is used to moderately limit the heat generation of the phase dynamic tuning unit 302. Specifically, the heat score can be measured by the operating temperature of the phase dynamic tuning unit 302; for example, the higher the temperature, the higher the heat score. Alternatively, the heat score can also be determined by the operating temperature and the operating time at that temperature; for example, the higher the temperature and the longer the operating time, the higher the heat score. Exemplarily, the specific heat score can be determined by a preset lookup table. For example, an engineer can set up a lookup table based on the initial design specifications of the chip system or the factory test data of the chip system. This lookup table includes the heat score under temperature range and operating time range.

[0060] Adjustments are made based on ambient temperature. When the ambient temperature is high, the set heat score is adjusted, such as reducing the set heat score (i.e., limiting the degree of thermo-optical modulation).

[0061] The method further includes S1023, monitoring the application duration of the current indicator deviation of the chip system, and updating or adjusting the tuning mode based on the application duration; specifically: If the index deviation is greater than or equal to the set deviation threshold and the application duration is less than the set duration threshold, then switch to the first phase tuning mode for modulation. If the index deviation is less than the set deviation threshold and the application duration is greater than the set duration threshold, then the mode is switched to the second phase tuning mode for modulation. That is, the mode is updated or adjusted based on the application duration of the index deviation.

[0062] For example, if the indicator deviation is large but only occurs for a short period of time, the first phase tuning mode is maintained, that is, dynamic tuning is performed only through the phase dynamic tuning unit 302; conversely, if a large deviation occurs for a long period of time, the second phase tuning mode is activated. The duration threshold ranges from 10us to 100us. Therefore, a more specific implementation method is as follows: In this embodiment, the initial default state can be the factory default state.

[0063] In this embodiment, the second phase tuning mode is a thermoelectric co-tuning mode.

[0064] It is understandable that the modulation / tuning goal of the chip system is to modulate the input light with a center wavelength λ1 into an output light with a center wavelength λ2. In other words, the tuner aims to change the center wavelength. Specifically, changing the center wavelength is achieved by adjusting the phase of the light wave. Therefore, the wavelength difference between center wavelength λ1 and center wavelength λ2 corresponds to a phase difference range, which is the target phase range that needs to be adjusted. Specifically, by modulating both the first and second phase ranges, the target phase range modulation can be achieved.

[0065] Specifically, referring to Embodiment 1, the non-volatile modulation unit 301 is preferably used as a coarse adjustment means, while the phase dynamic tuning unit 302 is used as a fine adjustment means, and the first phase range and the second phase range are selectively set accordingly. For example, the first phase range is usually larger than the second phase range.

[0066] Correspondingly, the method includes: 1. Monitor the indicator deviations that occur during the operation of the chip system, and record the application duration of the current indicator deviation; It is understood that the chip system in this embodiment is capable of wavelength selection. Correspondingly, the index deviation can be used to represent the deviation between the actual center wavelength (i.e., the actual operating wavelength) output by the chip system and the target center wavelength. The application duration refers to the duration after the index deviation occurs.

[0067] 2. Adjusting the tuning mode based on the aforementioned index deviation and application duration, including: (1) If the index deviation is greater than or equal to the set first deviation threshold and the application duration is less than the set first duration threshold, then switch to or continue to maintain the first phase tuning mode for modulation. In other words, when the deviation of the index is relatively large (i.e. the error of the chip system is considered to be slightly large), but it is only an occasional instantaneous fluctuation, it is still recommended to use the first phase tuning mode.

[0068] Conversely, if the deviation index is greater than or equal to the set first deviation threshold, and the application duration reaches or exceeds the first duration threshold, it is necessary to consider switching to the second phase tuning mode to ensure the chip's working accuracy.

[0069] (2) If the index deviation is less than the set first deviation threshold and greater than or equal to the set second deviation threshold, and the application duration is greater than the set second duration threshold, then switch or continue to maintain the second phase tuning mode for modulation.

[0070] In this embodiment, if the indicator deviation is moderate (i.e., a relatively obvious deviation has occurred, but it has not exceeded the highest warning line—the first deviation threshold), then its application time still needs to be limited. For example, if the indicator deviation is moderate but the duration is relatively long, then the second phase tuning mode is switched to control the deviation.

[0071] Conversely, if the index deviation is less than the set first deviation threshold and greater than or equal to the set second deviation threshold, but the application time is short, then switching to the second phase tuning mode can be temporarily suspended.

[0072] In this embodiment, since the second duration threshold is greater than the first duration threshold, different switching response sensitivities are set for different deviation magnitudes. The first deviation threshold is greater than the second deviation threshold. When the index deviation is less than the second deviation threshold, it indicates that the deviation is very small and within the allowable error range. Unless there are special requirements, no special processing is needed, and the current tuning mode can be maintained.

[0073] The method further includes S1024, identifying whether a continuous wave scan is triggered; if so, identifying the wavelength range of the continuous wave to be scanned, and dynamically adjusting the first phase range and the second phase range according to the wavelength range of the continuous wave to be scanned.

[0074] The system identifies whether a continuous wave scan has been triggered. If so, it identifies the wavelength range to be scanned and dynamically adjusts the first and second phase ranges accordingly. For example, the larger the wavelength range being scanned, the greater the working pressure on the tuning (non-volatile modulation unit 301 and phase dynamic tuning unit 302 (thermal phase shifter) working together). Therefore, the phase dynamic tuning unit 302 needs to be used less, and the allowable working range for the second phase is reduced, resulting in a smaller second phase range. If the wavelength range to be scanned is very small, the cavity phase disturbance caused by the coarse tuning of the non-volatile modulation unit 301 (PCM phase change material) is weak, the chip thermal load is low, and the compensation margin is sufficient. Therefore, there is no need to limit the dual tuning unit 300, and the second phase range maintains its full maximum value. Fine correction is achieved through the phase dynamic tuning unit 302 of the dual tuning unit 300, resulting in higher wavelength accuracy.

[0075] Specifically, the wavelength range here refers to the wavelength range covered by the continuous wave. For example, if the continuous wave scanning scenario involves scanning in the wavelength range of wavelength A to wavelength B, then the size of the wavelength range can be defined as |AB|.

[0076] A larger wavelength range typically means a greater number of different wavelengths needing modulation, resulting in greater modulation pressure on the light. Therefore, in this embodiment, for situations with high modulation pressure, it is recommended to activate the second phase tuning mode. The second phase tuning mode essentially redistributes the range modulation task to reduce the modulation pressure on the phase dynamic tuning unit 302.

[0077] Furthermore, in this embodiment, the working contribution of the non-volatile modulation unit 301 and the phase dynamic tuning unit 302 (i.e., corresponding to the first phase range and the second phase range) can be adaptively adjusted according to the different wavelength ranges, i.e., the different modulation pressures.

[0078] In some embodiments, dynamically adjusting the first phase range and the second phase range according to the wavelength range of the continuous wave to be scanned includes: When the wavelength range is greater than the preset range interval, it is recommended to reduce the proportion of the second phase range, wherein the proportion of the second phase range = second phase range / (first phase range and second phase range).

[0079] In this embodiment, when the scanning range is large, the modulation pressure is greater. At this time, it is desirable to appropriately reduce the modulation pressure of the phase dynamic tuning unit 302 (i.e., reduce the proportion of the second phase range) and transfer some of the modulation pressure to the non-volatile modulation unit 301.

[0080] From another perspective, in this embodiment, two operating conditions are considered: 1) the phase dynamic tuning unit 302 is used as a fine-tuning method; 2) the phase dynamic tuning unit 302 adopts a thermal tuning mode, meaning its operating accuracy is more sensitive to temperature. Therefore, in order to improve the overall operating stability of the chip system, this embodiment focuses on the operating status of the fine-tuning method and dynamically adjusts the contribution or pressure of the fine-tuning method in conjunction with the overall operating status of the chip system (such as using deviation indicators for feedback).

[0081] In some embodiments, reducing the proportion of the second phase range includes: the larger the wavelength range, the greater the reduction in the proportion of the second phase range. That is, in this embodiment, the larger the wavelength range, the greater the reduction in the proportion of the second phase range, which means a greater reduction in the workload of the fine-tuning method.

[0082] The method further includes step S1025, obtaining the operating status of the chip system in the previous period, and adjusting the set deviation threshold, duration threshold, or set heat score based on the operating status. Specifically, if the heat generation of the chip system is relatively high (e.g., high temperature during thermal adjustment) and the duration is long, then in the next stage, the three set thresholds can be appropriately lowered. That is, it is relatively preferable to use the non-volatile modulation unit 301 and the phase dynamic tuning unit 302 working together at this time. In other words, the current operating status indicates that the threshold setting is too high, which can easily cause overheating during operation. In order to protect the device, the threshold should be appropriately lowered to reduce the adjustment pressure, thereby reducing the use of the phase dynamic tuning unit 302.

[0083] The method further includes S1026, monitoring the drift deviation and drift deviation duration of the chip system performance, and if the drift deviation is greater than a set drift deviation threshold and the drift deviation duration is greater than a set drift deviation duration threshold, then the default state of the non-volatile modulation unit 301 is updated.

[0084] If a certain degree of performance drift deviation is detected in the chip over a long period, the default state of the non-volatile modulation unit 301 will be updated (initialized and reset). It should be noted that even chips produced in the same batch will have actual parameters that deviate from the design values ​​for each device. These deviations will directly lead to increased losses or wavelength shifts, and the non-volatile modulation unit 301 is preferably used to smooth out these deviations.

[0085] Furthermore, after a period of use, a monitoring program can be set to monitor these inherent performance deviations. For example, if the drive current and wavelength setting remain unchanged, but the power measured at the output monitoring terminal continues to decrease, it indicates that additional losses are occurring. In this case, the default state of the non-volatile modulation unit 301 can be updated (initialization reset). In addition, in the initial case, the non-volatile modulation unit 301 has a default state and is not easily adjusted.

[0086] The coarse adjustment of the non-volatile modulation unit 301 is equivalent to the factory modulation, providing the original maximum working range of the first phase, which is the basis for all wavelength scanning; the dynamic adjustment of the first phase range is essentially the cutting as needed within the factory coarse adjustment calibration range; the factory coarse adjustment calibrates the coupling relationship between the non-volatile modulation unit 301 and the phase compensation, which directly determines the compression ratio of the second phase window under different scanning spans; the scanning cycle only limits the coarse adjustment current adjustment speed and does not change the factory-calibrated coarse adjustment upper and lower limits.

[0087] Simultaneously, a dual modulation method employing a non-volatile modulation unit 301 and a phase dynamic tuning unit 302 is used in the phase modulation process. The non-volatile modulation unit 301 can complete the phase coarse adjustment after factory calibration or packaging, and can maintain the modulation state without continuous heat generation during operation. Combined with the real-time fine adjustment of the phase dynamic tuning unit 302, it not only ensures the accuracy of wavelength modulation, but also effectively controls the overall heat generation of the system, avoiding performance drift caused by heat accumulation during long-term operation, and adapting to the long-term stable operation requirements of glass substrate optical waveguide chip systems in different application scenarios. At the same time, this modulation method can autonomously switch the tuning mode according to the real-time operating parameters of the chip system (ambient temperature, operating conditions, etc.), taking into account both communication performance and operating power consumption, and improving the adaptability of the large-scale chip system of the optical waveguide external cavity to complex operating environments.

[0088] S103, the beam is split by the beam splitting unit 500, the wavelength offset deviation of the output light in step S102 is monitored, and the corresponding wavelength tuning mode is configured for the dual tuning module according to the wavelength offset deviation of the light; then the closed-loop feedback is monitored and output.

[0089] Step S103 includes: S1031, the specific steps for configuring the corresponding wavelength tuning mode based on the wavelength offset deviation are as follows: When the wavelength offset deviation is less than the set wavelength offset deviation threshold, the first wavelength selection tuning mode is activated. The first wavelength selection tuning mode is: the wavelength non-volatile modulation unit maintains the initial default state and the wavelength dynamic tuning unit is called to perform wavelength modulation. When the wavelength offset deviation is greater than or equal to the set wavelength offset deviation threshold, the second wavelength selection tuning mode is activated. The second wavelength selection tuning mode is as follows: the wavelength non-volatile modulation unit performs wavelength modulation in the first wavelength range, and the wavelength dynamic tuning unit performs wavelength modulation in the second wavelength range.

[0090] When the wavelength offset deviation is small, configuring the first wavelength selection tuning mode to complete the fine adjustment of the wavelength can ensure that the wavelength of the output light reaches the target value. When the wavelength offset deviation is large, configuring the second wavelength selection tuning mode first completes the coarse adjustment through the wavelength non-volatile modulation section, and then completes the fine adjustment through the wavelength dynamic tuning section. This ensures that the tuning range covers large deviations while maintaining a high-precision tuning effect.

[0091] Step S103 includes: S1032, the specific method for monitoring the closed-loop feedback is as follows: (1) External cavity chip status calibration: Before coupling the gain chip 200, the loop transmission spectrum of the third output monitoring terminal O3 and the fourth output monitoring terminal O4 is tested. When the third output monitoring terminal O3 is greater than the fourth output monitoring terminal O4, the relationship between the first wavelength non-volatile modulation unit 401 and the first dynamic tuning unit 402 and the resonant wavelength is calibrated. At the same time, the loop transmission spectrum of the first output monitoring terminal O1 and the second output monitoring terminal O2 is tested. When the first output monitoring terminal O1 is greater than the second output monitoring terminal O2, the relationship between the second wavelength non-volatile modulation unit 403 and the second dynamic tuning unit 404 and the resonant wavelength is calibrated. Finally, test whether the waveguide at the input end of the gain chip 200 on the glass substrate optical waveguide chip 100 is greater than the laser output transmission spectrum. If so, calibrate the relationship between the second non-volatile modulation section 501 and the beam splitting ratio / coupling coefficient. (2) Gain chip 200 calibration: Calibrate the output power under different currents; (3) Joint debugging of external cavity chip and gain chip 200: Based on the above calibration, the beam splitting ratio and wavelength modulation are performed by the second non-volatile modulation section 501 in the beam splitting unit 500 and / or the wavelength dynamic tuning section in the wavelength selection unit 400. The external cavity transmission wavelength is used as the target wavelength, and the phase is modulated by the dual tuning unit 300 to maximize the power. The operating parameters of the dual tuning unit 300 at each wavelength are calibrated accordingly.

[0092] Furthermore, an asymmetric MZI interference structure for monitoring wavelength can be set on the chip to form a closed-loop control with the wavelength selection unit 400.

[0093] It should be noted that the control logic of wavelength selection tuning and phase tuning is the same. During wavelength tuning, the tuning mode and parameter configuration can also be dynamically adjusted based on the chip's current ambient temperature, deviation duration, scanning wavelength range, and historical operating status: when the ambient temperature is high, the operating percentage of the wavelength dynamic tuning unit is limited to reduce heat accumulation; when a large wavelength deviation only occurs for a short time, the first wavelength selection tuning mode is maintained first to avoid frequent operation of the wavelength non-volatile modulation unit; when the range of wavelengths to be scanned is larger, the allowable operating range of the wavelength dynamic tuning unit is appropriately reduced, and the wavelength non-volatile modulation unit undertakes more coarse tuning work to reduce the overall thermal load of the chip; if the chip experiences long-term continuous drift during long-term operation, the default state of the wavelength non-volatile modulation unit needs to be updated to complete the wavelength calibration reset.

[0094] When the second wavelength selection tuning mode is activated, step S104 is executed, limiting the modulation range of the wavelength dynamic tuning unit or the phase dynamic tuning unit 302 according to a preset priority rule. The priority rule is as follows: both the dual tuning unit 300 and the wavelength selection unit 400 are set with different priority levels. When the priority level is greater than a set priority threshold, the modulation range of the corresponding dual tuning unit or wavelength selection unit is limited. Since the dual tuning module involves multiple dual tuning structures (dual tuning unit 300 and two wavelength selection units 400), from a comprehensive optimization perspective, the following linkage mechanism is involved (considering the background: the power consumption of wavelength selection is often much higher than that of phase selection): when both the dual tuning unit 300 and the wavelength selection unit 400 trigger dual-mode operation (i.e., both PCM phase change material and thermo-optic modulation are invoked); the application ratio / degree (such as its adjustment range) of the phase dynamic tuning unit 302 (i.e., thermoelectric operation) in the dual tuning unit 300 is allowed to be moderately reduced to reduce necessary heat dissipation.

[0095] Furthermore, in this embodiment, the micro-rings in the dual-tuning unit 300 and the two wavelength selection units 400 are respectively configured as a large ring (the first micro-ring with a relatively large diameter, i.e., the first wavelength selection unit) and a small ring (the second micro-ring with a relatively small diameter, i.e., the second wavelength selection unit), and the first wavelength selection unit (large ring) and the second wavelength selection unit (small ring) are assigned different priorities. The higher the priority, the more preferentially it will be restricted when hot-tuning is limited. For example, a priority threshold is generated based on the current operational risk, and finally, the priority higher than the priority threshold is selected for hot-tuning restriction. The higher the operational risk, the lower the priority threshold. For example, in some embodiments, the operational risk is higher when the ambient temperature of the chip system exceeds a set safe temperature, and the higher the ambient temperature, the higher the operational risk.

[0096] Specifically: Step S104 includes: S1041, obtain the current operating risk of the chip system, generate a priority threshold based on the current operating risk, select the dual tuning unit 300 or wavelength selection unit 400 with a priority level greater than the priority threshold, and limit the modulation range of its corresponding phase dynamic tuning unit 302 or wavelength dynamic tuning unit. The two wavelength selection units 400 are a first wavelength selection unit and a second wavelength selection unit, respectively. Both the first wavelength selection unit and the second wavelength selection unit are micro-ring filter cavities, and the micro-ring diameter of the first wavelength selection unit is larger than the micro-ring diameter of the second wavelength selection unit. S1042, if the operational risk is greater than the preset first risk threshold and less than or equal to the second risk threshold, and the application scenario prioritizes communication maintenance, then the second wavelength selection unit has the highest priority, and the first wavelength selection unit has the next highest priority. In this case, the modulation range of the second dynamic tuning unit 404 is restricted first. If the operational risk is greater than the preset second risk threshold, the modulation range of the phase dynamic tuning unit 302 will also be restricted. S1043, if the operational risk is greater than the preset first risk threshold and less than or equal to the second risk threshold, and the application scenario prioritizes phase accuracy or linearity, then the dual tuning unit 300 has the highest priority, followed by the first wavelength selection unit. In this case, the modulation range of the phase dynamic tuning unit 302 is restricted first. If the operational risk is greater than the preset second risk threshold, the modulation range of the second dynamic tuning unit 404 will also be restricted.

[0097] For example, in some embodiments, the modulation range can be the phase range to be modulated.

[0098] For example, in some embodiments, the modulation range can be the wavelength modulation range to be modulated (i.e., there is a wavelength difference between the center wavelength λ1 of the input light and the center wavelength λ2 of the output light, and this wavelength difference can be split into two wavelength modulation ranges that are modulated separately by different modulation units or tuning units).

[0099] In some specific embodiments, the priority is set according to the application scenario information, specifically as follows: Scenario 1) When the application scenario prioritizes communication maintenance, the wavelength selection unit 400 (dual-tuned micro-ring (dual ring)) has the highest priority (and the second wavelength selection unit (small ring) has a higher priority than the first wavelength selection unit (large ring)), while the phase dynamic tuning section 302 in the dual-tuned unit 300 (thermal phase shifter) has the next highest priority. Reason: If the wavelength selection unit 400 (dual-tuned micro-ring) overheats, it will cause the coincidence point to shift, and the laser will directly hop frequency or lose lock, resulting in the interruption of the entire communication link. This is a catastrophic failure. Therefore, temperature control must prioritize ensuring the temperature stability of the wavelength selection unit 400 (dual-tuned micro-ring). The dual-tuned unit 300 (thermal phase shifter) has the next highest priority. Overheating of the thermal phase shifter will cause a decrease in modulation efficiency (Vπ drift), but usually the receiver's DSP (digital signal processor) has sufficient equalization algorithms to compensate, so the link will not be completely broken, only the signal-to-noise ratio will slightly decrease.

[0100] Scenario 2) When phase accuracy and linearity are the primary objectives in an application scenario, the thermal phase shifter has the highest priority. In a sensing system, the linearity of the triangular wave (linear frequency modulation) generated by the thermal phase shifter directly determines the ranging accuracy. Nonlinear distortion caused by thermal effects directly translates into measurement error and cannot be fully corrected by subsequent algorithms. Heat dissipation must be prioritized to ensure the thermal phase shifter remains at a constant temperature. Wavelength selection unit 400 (dual-tuned microring): secondary priority (with the larger ring taking precedence over the smaller ring). Sensing systems typically operate at a fixed wavelength. Once the dual-tuned microring has locked onto its center wavelength, significant tuning is not required in a short period. As long as the slow drift of the dual-tuned microring does not exceed the compensation range of the phase shifter, a slightly higher temperature for the microring is permissible.

[0101] If the operational risks increase further (e.g., increased ambient temperature or heightened overheating risk), the different microrings in the two wavelength selection units 400 (dual-tuned microrings) can be further subdivided. Specifically, the proportion of thermo-optical modulation in the larger ring (first wavelength selection unit) can be appropriately reduced.

[0102] The specific working principle of the tuner consisting of two wavelength selection units 400 (the first wavelength selection unit is the first micro-ring, and the second wavelength selection unit is the second micro-ring): The two microrings operate synchronously in the system, creating a vernier caliper effect. They have different free spectral ranges (FSRs), with the larger ring having a smaller FSR (closer comb teeth) and the smaller ring having a larger FSR (sparser comb teeth). Only when a pair of resonance peaks in the two comb-shaped reflection spectra coincide at a specific wavelength can the lasing condition of the laser be met.

[0103] During modulation, the chip system simultaneously controls two microrings (e.g., through thermo-optic or electro-optic effects), altering their effective refractive indices and causing a slight shift in their respective comb-shaped reflection spectra. Due to the slight difference in the FSRs of the two rings, this synchronization shift leads to a significant jump in the point of coincidence, thereby achieving wide-range tuning of the lasing wavelength. Ultimately, the first and second microrings (i.e., the first wavelength selection unit and the second wavelength selection unit) jointly determine the final position of the output wavelength.

[0104] In a microring tuner, the comb teeth refer to individual resonant peaks in the transmission or reflection spectrum of the microring. A wavelength can only be selected when a tooth of one of the two sets of comb teeth aligns (coincides) at a specific wavelength. During modulation, the two sets of comb teeth move relative to each other, and the point of coincidence jumps significantly, thus achieving a wide range of wavelength selection.

[0105] Specifically, if the phase deviation to be adjusted in the wavelength selection unit 400 is large (specifically, in the wavelength selection unit 400, the resonance condition is changed by phase adjustment to achieve the selection of the center wavelength), it is recommended to call the wavelength non-volatile modulation unit and the wavelength dynamic tuning unit simultaneously (i.e., start the second wavelength selection tuning mode); otherwise, only the wavelength dynamic tuning unit can be called.

[0106] The drawbacks of the PCM phase change material layer 104 (non-volatile modulation section 301 or / and first wavelength non-volatile modulation section 401, second wavelength non-volatile modulation section 403 or / and second non-volatile modulation section 501) are relatively high loss and nonlinearity, but relatively low power consumption for adjustment; thermo-optical adjustment has higher power consumption, but the modulation has linear continuity and low loss. Therefore, by combining the above methods and dynamically selecting them, the advantages of both can be balanced as much as possible under complex operating environments.

[0107] The optical path transmission of this chip system is specifically as follows: After the optical signal is emitted from the gain chip 200 (RSOA), it is coupled into the first transmission waveguide I on the glass substrate 101 (which is equivalent to a part of the optical waveguide layer 102). It then propagates within the waveguide to the external cavity beam splitting unit 500. The split beams pass through the wavelength selection unit 400 clockwise and counterclockwise respectively, and then reach the beam splitting unit 500 again for coherent beam combining. Part of the combined beam is fed back to the gain chip 200 (RSOA) to maintain oscillation, while the other part of the transmitted beam is output from the laser output terminal O5 through the working output waveguide II2 and the beam splitting monitoring unit 105 (i.e., the monitoring waveguide) to the outside of the chip. During this process, the non-volatile modulation unit 301 and the phase dynamic tuning unit 302, as well as the wavelength non-volatile modulation unit and the wavelength dynamic tuning unit, work together to coarsely and finely adjust the effective refractive index of the waveguide, respectively, thereby achieving precise control of the output wavelength.

[0108] Through the aforementioned dual-tuning mechanism, this application enables the method to utilize the low heat generation and wide tuning range of the non-volatile modulation unit 301 / wavelength non-volatile modulation unit to complete large-range coarse tuning and deviation calibration. It balances tuning range, tuning accuracy, and long-term thermal stability of the chip, adapting to the wavelength selection requirements of large-range chip systems with glass substrate optical waveguide external cavities in different scenarios.

[0109] Example 3: The present invention also provides a wavelength selection method for monitoring feedback as follows: The chip system includes: a glass substrate optical waveguide chip 100; a gain chip 200 for providing broadband light; and a dual-tuning module including: a dual-tuning unit 300, a beam splitting unit 500, and at least two wavelength selection units 400 arranged sequentially on the glass substrate optical waveguide chip 100, wherein the beam splitting unit 500 and the wavelength selection units 400 together constitute a Sagnac resonant cavity, and the dual-tuning unit 300 is coupled to the Sagnac resonant cavity. The dual-tuning unit 300 includes a non-volatile modulation section 301 and a phase dynamic tuning section 302; the wavelength selection unit 400 includes a wavelength non-volatile modulation section and a wavelength dynamic tuning section; both the non-volatile modulation section 301 and the wavelength non-volatile modulation section include a phase change material, and the non-volatile modulation section 301 or the wavelength non-volatile modulation section modulates the phase change material by means of optical pulses, electrical pulses or thermal excitation, so that the phase change material is in a crystalline or amorphous state; both the phase dynamic tuning section 302 and the wavelength dynamic tuning section change the wavelength of the output light by heating the optical waveguide and adjusting the resonance conditions; Correspondingly, the method includes: (1) The input light is divided into working output light and monitoring output light by the beam splitting monitoring unit 105, and the wavelength offset deviation between the output light and the target output light is monitored. The corresponding wavelength tuning mode is configured for the dual tuning module according to the wavelength offset deviation. The output light of the laser output terminal O5 is monitored and feedback is closed, and the light is modulated multiple times until the wavelength meets the target value before output.

[0110] In this embodiment, wavelength drift deviation can refer to the difference between the center wavelengths of the monitoring output light and the target output light.

[0111] The steps for configuring the corresponding wavelength tuning mode for the dual-tuning module based on the wavelength offset deviation include: (2) When the wavelength offset deviation is less than the set wavelength offset deviation threshold, the first wavelength selection tuning mode is enabled. The first wavelength selection tuning mode is: the wavelength non-volatile modulation unit maintains the initial default state and the wavelength dynamic tuning unit is called to perform wavelength modulation.

[0112] Furthermore, it also includes: when the wavelength offset deviation is greater than or equal to a set wavelength offset deviation threshold, a second wavelength selection tuning mode is enabled. The second wavelength selection tuning mode is: the wavelength non-volatile modulation unit performs wavelength modulation in the first wavelength range, and the wavelength dynamic tuning unit performs wavelength modulation in the second wavelength range.

[0113] Furthermore, in some specific embodiments, see [link to specific embodiments]. Figure 5 The steps for closed-loop feedback of the output light at laser output terminal O5 include: (1) During the continuous operation of the laser, the power of the output light of the first output monitoring terminal O1 and the fourth output monitoring terminal O4 is monitored in real time. Based on the power of the two output lights, the current beam splitting ratio of the beam splitting unit 500 is obtained. If there is a deviation between the current beam splitting ratio and the beam splitting ratio of the target wavelength, the beam splitting ratio of the beam splitting unit 500 is tuned in real time through the second non-volatile modulation section 501 in the tunable MZI structure of the beam splitting unit 500 and / or the wavelength dynamic tuning section in the wavelength selection unit 400. The relationship between the power P1 of the first output monitoring terminal and the power P4 of the fourth output monitoring terminal and the beam splitting ratio K is: K=P4 / (P1+P4)). The specific steps for adjusting the beam splitting ratio are as follows: If the beam splitting ratio deviation is greater than the second beam splitting ratio deviation threshold, it means that the deviation is very large and exceeds the range that the beam splitting ratio can be adjusted by tuning through the wavelength range. In this case, the second non-volatile modulation unit 501 needs to be activated to perform a large-range coarse adjustment. If the beam splitting ratio deviation is greater than the first beam splitting ratio deviation threshold and less than or equal to the second beam splitting ratio deviation threshold, then the wavelength selection unit 400 configures the corresponding wavelength tuning mode for the dual tuning module according to the wavelength offset deviation, thereby achieving the purpose of adjusting the beam splitting ratio. If the current beam splitting ratio deviation is less than the first beam splitting ratio deviation threshold or there is no deviation, then step (2) is executed; that is, if the beam splitting ratio meets the target value, further monitor whether the output light power remains at its maximum. (2) Real-time monitoring of the output light power at the monitoring end of the beam splitting monitoring unit 105 to obtain the power offset deviation; configuring the corresponding phase tuning mode for the dual-tuning module according to the power offset deviation, and modulating the phase in real time through the dual-tuning unit 300 to keep the output power at its maximum; specifically: When the power offset deviation is less than the set power offset deviation threshold, the first phase tuning mode is activated. When the power offset deviation is greater than or equal to the set power offset deviation threshold, the second phase tuning mode is activated.

[0114] It should be noted that this invention provides different solutions for various potential faults that may be encountered in practical applications. Therefore, it will be understood by those skilled in the art that, where there is no conflict, these solutions can be combined or switched according to the needs of those skilled in the art.

[0115] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0116] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a computer terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0117] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A wavelength selection method for a large-range chip system based on a glass substrate optical waveguide external cavity, characterized in that, The chip system includes: Glass substrate optical waveguide chip; gain chip, used to provide broadband light; A dual-tuning module includes: a dual-tuning unit, a beam splitting unit, and at least two wavelength selection units arranged sequentially on a glass substrate optical waveguide chip, wherein the beam splitting unit and the wavelength selection units together constitute a Sagnac resonant cavity, and the dual-tuning unit is coupled to the Sagnac resonant cavity; a beam splitting monitoring unit is provided at one output end of the beam splitting unit. The dual-tuning unit includes a non-volatile modulation section and a phase dynamic tuning section. The wavelength selection unit includes: a wavelength non-volatile modulation section and a wavelength dynamic tuning section; Both the non-volatile modulation section and the wavelength non-volatile modulation section include phase change materials; Correspondingly, the method includes: The beam splitting monitoring unit divides the output light into working output light and monitoring output light, and monitors the wavelength offset deviation of the monitoring output light. Based on the wavelength offset deviation, the corresponding wavelength tuning mode is configured for the dual tuning module. Then, the output light of the laser is monitored and feedback is closed, and the light is modulated multiple times until the wavelength meets the target value before output. The steps for configuring the corresponding wavelength tuning mode for the dual-tuning module based on the wavelength offset deviation include: When the wavelength offset deviation is less than the set wavelength offset deviation threshold, the first wavelength selection tuning mode is activated. The first wavelength selection tuning mode is: the wavelength non-volatile modulation unit maintains the initial default state and the wavelength dynamic tuning unit is called to perform wavelength modulation. When the wavelength offset deviation is greater than or equal to the set wavelength offset deviation threshold, the second wavelength selection tuning mode is activated. The second wavelength selection tuning mode is as follows: the wavelength non-volatile modulation unit performs wavelength modulation in the first wavelength range, and the wavelength dynamic tuning unit performs wavelength modulation in the second wavelength range.

2. The wavelength selection method for a large-range chip system based on a glass substrate optical waveguide external cavity according to claim 1, characterized in that, The steps of monitoring the output light of the laser and providing closed-loop feedback in the method include: The power of the laser's output light is monitored in real time to obtain the power offset deviation; the corresponding phase tuning mode is configured for the dual-tuning module based on the power offset deviation; specifically: When the power offset deviation is less than the set power offset deviation threshold, the first phase tuning mode is activated. When the power offset deviation is greater than or equal to the set power offset deviation threshold, the second phase tuning mode is activated.

3. The wavelength selection method for a large-range chip system based on a glass substrate optical waveguide external cavity according to claim 1, characterized in that, When the second wavelength selection tuning mode is activated, the following steps are executed: The modulation range of the wavelength dynamic tuning unit or the phase dynamic tuning unit is limited according to a preset priority rule. The priority rule is as follows: both the dual tuning unit and the wavelength selection unit are set with different priority levels. When the priority level is greater than the set priority threshold, the modulation range of the corresponding dual tuning unit or wavelength selection unit will be limited.

4. The wavelength selection method for a large-range chip system based on a glass substrate optical waveguide external cavity according to claim 3, characterized in that, When the second wavelength selection tuning mode is activated, the following steps are also included: The system acquires the current operational risk of the chip system and generates a priority threshold based on the current operational risk. It then selects dual-tuning units or wavelength selection units with a priority level greater than the priority threshold and limits the modulation range of their corresponding phase dynamic tuning units or wavelength dynamic tuning units.

5. The wavelength selection method for a large-range chip system based on a glass substrate optical waveguide external cavity according to claim 4, characterized in that, The two wavelength selection units are a first wavelength selection unit and a second wavelength selection unit, both of which are micro-ring filter cavities, and the micro-ring diameter of the first wavelength selection unit is larger than that of the second wavelength selection unit.

6. The wavelength selection method for a large-range chip system based on a glass substrate optical waveguide external cavity according to claim 5, characterized in that, When the second wavelength selection tuning mode is activated, the following steps are also included: If the operational risk is greater than the preset first risk threshold and less than or equal to the second risk threshold, and the application scenario prioritizes communication maintenance, then the second wavelength selection unit has the highest priority, followed by the first wavelength selection unit. In this case, the modulation range of the wavelength dynamic tuning unit is restricted first.

7. The wavelength selection method for a large-range chip system based on a glass substrate optical waveguide external cavity according to claim 6, characterized in that, When the second wavelength selection tuning mode is activated, the following steps are also included: if the operating risk is greater than the preset second risk threshold, then the modulation range of the phase dynamic tuning unit is limited.

8. The wavelength selection method for a large-range chip system based on a glass substrate optical waveguide external cavity according to claim 5, characterized in that, When the second wavelength selection tuning mode is activated, the following steps are also included: If the operational risk is greater than the preset first risk threshold and less than or equal to the second risk threshold, and the application scenario prioritizes phase accuracy or linearity, then the dual-tuning unit has the highest priority, followed by the first wavelength selection unit. In this case, the modulation range of the phase dynamic tuning unit is restricted first.

9. The wavelength selection method for a large-range chip system based on a glass substrate optical waveguide external cavity according to claim 8, characterized in that, When the second wavelength selection tuning mode is activated, the following steps are also included: if the operating risk is greater than the preset second risk threshold, then the modulation range of the wavelength dynamic tuning unit is limited.

10. The wavelength selection method for a large-range chip system based on a glass substrate optical waveguide external cavity according to claim 1, characterized in that, The beam splitting unit adopts a beam splitting ratio tunable MZI structure, and one arm of the beam splitting ratio tunable MZI structure includes a second non-volatile modulation section for modulating the phase.

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