A temperature-compensated optical transmit link package structure

Abstract

The utility model discloses a kind of temperature compensation-free optical transmission link packaging structures, belong to optical transmission link technical field, specific structure includes semiconductor optical amplifier, LRSPP coupler, first straight waveguide, second straight waveguide, micro-ring resonator and Bragg grating reflector, the first port of LRSPP coupler is connected to the output port of semiconductor optical amplifier, the second port of LRSPP coupler is connected to first straight waveguide, first straight waveguide is connected to the first port of micro-ring resonator, the second port of micro-ring resonator is connected to Bragg grating reflector, the third port of LRSPP coupler is connected to second straight waveguide as optical path output, semiconductor optical amplifier has high reflector.The utility model temperature changes, the micro-ring of micro-ring resonator and BGR's resonant wavelength synchronous drift, always keep matching, finally output high-quality optical signal, without additional temperature control device, wavelength automatic matching can be realized in wide temperature zone, while reducing coupling loss, guarantee signal quality.

Description

Technical Field

[0001] This utility model belongs to the field of optical transmission link technology, specifically relating to a temperature-compensated optical transmission link packaging structure. Background Technology

[0002] Traditional optical transmission links rely on temperature control devices to ensure wavelength matching between the light source and the modulator. However, additional temperature control devices increase size, power consumption, and cost, and reduce integration density. At the same time, high coupling loss between optical devices affects signal quality and limits their application in high-density optoelectronic integrated systems. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a temperature-compensated optical emission link packaging structure that can achieve automatic wavelength matching in a wide temperature range without the need for an additional temperature control device, while reducing coupling loss, ensuring signal quality, and reducing size, power consumption and cost.

[0004] The technical solution adopted in this utility model is as follows: a temperature-compensated optical emission link packaging structure, including a semiconductor optical amplifier (SOA), an LRSPP coupler, a first straight waveguide, a second straight waveguide, a micro-ring resonator, and a Bragg grating reflector (BGR). The first port of the LRSPP coupler is connected to the output port of the semiconductor optical amplifier, the second port of the LRSPP coupler is connected to the first straight waveguide, the first straight waveguide is connected to the first port of the micro-ring resonator, the second port of the micro-ring resonator is connected to the Bragg grating reflector, and the third port of the LRSPP coupler is connected to the second straight waveguide, which serves as the optical output. The semiconductor optical amplifier has a high-reflectivity mirror (HRM). The semiconductor optical amplifier, LRSPP coupler, first straight waveguide, second straight waveguide, micro-ring resonator, and Bragg grating reflector constitute an external cavity semiconductor laser, which outputs light in a waveguide parallel coupling manner.

[0005] Furthermore, the aforementioned temperature-compensated optical transmission link packaging structure also includes a modulation link, which is connected to a second straight waveguide that serves as the optical output, for modulating and transmitting the output optical signal at high speed.

[0006] Furthermore, the aforementioned modulation link includes a micro-ring resonant modulator and a third straight waveguide. The first port of the micro-ring resonant modulator is connected to the second straight waveguide, and the second port of the micro-ring resonant modulator is connected to the third straight waveguide. The micro-ring resonant modulator has the same structure and material as the micro-ring resonator.

[0007] Furthermore, the LRSPP coupler described above adopts an LRSPP wedge coupler.

[0008] Furthermore, the aforementioned semiconductor optical amplifier, LRSPP coupler, first straight waveguide, second straight waveguide, micro-ring resonator, Bragg grating reflector, micro-ring resonator modulator, and third straight waveguide are integrated and packaged on a silicon substrate using micro-nano technology, resulting in higher integration.

[0009] The beneficial effects of this invention are as follows: Compared with the prior art, when the temperature changes, the micro-ring of the micro-ring resonator and the resonant wavelength of the BGR drift synchronously and always remain matched, ultimately outputting a high-quality optical signal. No additional temperature control device is required, and automatic wavelength matching can be achieved in a wide temperature range. At the same time, coupling loss is reduced, signal quality is guaranteed, and the size, power consumption and cost are reduced. Attached Figure Description

[0010] Figure 1 is a three-dimensional schematic diagram of the packaging structure of the optical emission link without temperature compensation;

[0011] Figure 2 A three-dimensional schematic diagram of the packaging structure of a temperature-compensated optical emission link;

[0012] Figure 3 This is a schematic diagram of the principle of a temperature-compensated optical emission link.

[0013] Figure 4 The diagram shows the spectral relationship between the microring resonator and the BGR. The relationship between the reflection bandwidth and reflectivity of the BGR and the resonant wavelength of the microring resonator needs to meet certain requirements. The reflection spectrum of the BGR needs to be reflected by the resonant peak of the microring resonator modulator to achieve wavelength feedback.

[0014] Figure 5 Output power diagrams of integrated light sources under different coupling losses;

[0015] Figure 6 The graph shows the displacement of the center wavelength of the microring resonator at different temperatures;

[0016] Figure 7 Output power diagrams of coupled integrated light sources at different temperatures;

[0017] Figure 8 Eye diagrams of the output signal of the optical transmitter link at different temperatures: (a) 20℃, (b) 60℃. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0019] Example 1: As Figure 1-8As shown, a temperature-compensated optical emission link packaging structure includes a semiconductor optical amplifier 2, an LRSPP coupler 3, a first straight waveguide 3, a second straight waveguide 4, a micro-ring resonator 5, and a Bragg grating reflector 4. The first port of the LRSPP coupler 3 is connected to the output port of the semiconductor optical amplifier 2, the second port of the LRSPP coupler 3 is connected to the first straight waveguide 6, the first straight waveguide 6 is connected to the first port of the micro-ring resonator 5, the second port of the micro-ring resonator 5 is connected to the Bragg grating reflector 4, and the third port of the LRSPP coupler 3 is connected to the second straight waveguide 7, which serves as the optical output. The semiconductor optical amplifier 2 has a high-reflectivity mirror 1. The semiconductor optical amplifier 2, LRSPP coupler 3, first straight waveguide 6, second straight waveguide 7, micro-ring resonator 5, and Bragg grating reflector 4 constitute an external cavity semiconductor laser, outputting light in a waveguide parallel coupling manner. It also includes a modulation link connected to the second straight waveguide 7, which serves as the optical output, for modulating and high-speed transmitting the output optical signal. The laser cavity can be composed of an SOA and a BGR. The resulting Fabry-Perot (FP) cavity is constructed. This novel temperature-compensated optical emission link achieves a more balanced performance in terms of structural compactness, modulation speed, operating wavelength range, temperature stability, and wavelength control.

[0020] Among them, the semiconductor optical amplifier (SOA) is integrated using a flip-chip bonding process and is used for optical signal amplification;

[0021] LRSPP coupler: placed between SOA and the first straight waveguide (silicon-based waveguide) to achieve mode matching between SOA and silicon-based waveguide and reduce coupling loss;

[0022] Micro-ring resonator: optically coupled to the LRSPP coupler to perform resonant frequency selection on the optical signal;

[0023] Bragg grating reflector (BGR): Optically coupled to a microring resonator, its reflection spectrum center wavelength shift characteristics are adapted to the temperature drift characteristics of the microring resonator's resonant wavelength, so that the resonant peak of the microring resonator is contained within the reflection window of the BGR. This ensures that, without additional temperature control, the oscillation wavelength of the integrated light source and the resonant wavelength of the microring resonator modulator automatically match with temperature.

[0024] Specifically, the modulation link includes a micro-ring resonator modulator 8 and a third straight waveguide 9. The first port of the micro-ring resonator modulator 8 is connected to the second straight waveguide 7, and the second port of the micro-ring resonator modulator 8 is connected to the third straight waveguide 9. The micro-ring resonator modulator 8 and the micro-ring resonator 5 have the same structure and material to ensure that their resonant wavelength temperature drift characteristics (Δλ / ΔT) are consistent. The first straight waveguide 6, the second straight waveguide 7 and the third straight waveguide 9 are all silicon-based optical waveguides.

[0025] The modulation link consists of a straight waveguide and a micro-ring resonator. Each part achieves stable modulation without temperature compensation through resonant wavelength matching and thermo-optical synergy. Its specific relationship with the external cavity semiconductor laser is as follows:

[0026] 1) Consistency of resonant wavelength:

[0027] The micro-ring resonant modulator has the same structure as the micro-ring resonator, ensuring that the resonant wavelengths of the two are consistent. At the same time, the reflection bandwidth of the BGR needs to cover the resonant peak of the micro-ring resonant modulator, and the matching between the emission wavelength of the light source and the operating wavelength of the modulator is further locked through the feedback mechanism.

[0028] 2) Complementarity of thermo-optical effects:

[0029] The center resonant wavelength of the microring resonator (dominated by Si material) changes with temperature at a rate of 0.0452 nm / ℃, while the center wavelength shift rate of the BGR's reflection spectrum is 0.0475 nm / ℃. Although the thermo-optic coefficients of the two are slightly different, the width and gradient design of the BGR's reflection window enable it to achieve spectral reflection adaptation over a wide temperature range, ultimately ensuring dynamic matching of the wavelengths of the light source and the modulator without temperature compensation.

[0030] The core role of the modulation link in the optical transmission link: The modulation link is the key link to realize "optical signal modulation → high-speed optical transmission". Its specific role can be broken down from three dimensions: performance, application scenarios, and innovative value.

[0031] 1) Achieving high-speed optical modulation and signal transmission:

[0032] The optical carrier output from the SOA is modulated by a micro-ring resonant modulator, enabling the optical signal to carry electrical information (such as data and commands) and ultimately transmit at high speed in the form of light. At a transmission rate of 50 Gb / s, the link can output high-quality eye diagrams at both 20°C and 60°C, demonstrating its high-speed modulation reliability over a wide temperature range.

[0033] 2) Breaking through the limitations of traditional temperature compensation and expanding application scenarios:

[0034] Traditional optical transmission links rely on temperature control devices (such as thermoelectric coolers) to maintain wavelength matching. However, this modulation link, through the thermo-optical co-design of microring resonators and BGRs, can maintain wavelength matching over a wide temperature range (such as 20°C to 60°C) without additional temperature compensation structures, significantly reducing system complexity and power consumption. It is suitable for scenarios that are sensitive to size and power consumption (such as optical communication modules and integrated photonic chips).

[0035] 3) Improve integration and functional scalability:

[0036] The link adopts an integrated architecture of "SOA + micro-ring resonator + BGR", which can extend the operating wavelength range and multi-channel output through the cascading of micro-ring resonator modulators, providing a technical foundation for the integration of high-density photonic devices (such as on-chip optical interconnects and optical sensing arrays).

[0037] In summary, the modulation link, through its design of resonant wavelength matching and thermo-optical synergy, plays a core role in the optical transmission link by enabling "high-speed optical modulation, wavelength self-adaptation without temperature compensation, and high-density integration and expansion," and is a key link in realizing the performance advantages of this optical transmission link.

[0038] For light waves to form a strong resonance in a micro-ring (both micro-ring resonant modulators and micro-ring resonators form strong resonances), the following conditions must be met:

[0039]

[0040] In the formula, The center resonant wavelength, The perimeter of the path taken by the light wave in the micro-ring. For the effective refractive index, m is a positive integer, indicating that the light coupled into the microring accumulates m 2π phases in the return coupling region.

[0041] LRSPP coupler 3 adopts an LRSPP wedge coupler. LRSPP coupler 3 has a wedge structure. By optimizing geometric parameters such as wedge angle and length, the mode conversion efficiency is improved.

[0042] The SOA and silicon waveguide are parallel coupled through an LRSPP coupler. The coupling coefficient of the LRSPP coupler is designed to be 0.5 to balance coupling efficiency and transmission loss.

[0043] To improve packaging stability, the semiconductor optical amplifier 2, LRSPP coupler 3, first straight waveguide 6, second straight waveguide 7, micro-ring resonator 5, Bragg grating reflector 4, micro-ring resonator modulator 8, and third straight waveguide 9 are integrated and packaged on the silicon substrate 10 using micro-nano technology. The optical link is then integrated into the substrate of the packaged silicon substrate 10 using micro-nano technology to complete the optical link packaging.

[0044] Working principle: After the SOA amplifies the optical signal, it is coupled to the first straight waveguide via the LRSPP coupler. The first straight waveguide sends the optical signal into the micro-ring resonator for resonant frequency selection. The BGR reflects the optical signal with the matching wavelength, forming the narrow wavelength of the FP resonant cavity. When the temperature changes, the micro-ring of the micro-ring resonator and the resonant wavelength of the BGR drift synchronously, always maintaining matching, and finally outputting a high-quality optical signal. The output high-quality optical signal is then modulated by the micro-ring resonator modulator in the modulation link. The micro-ring resonator modulates and transmits the output optical signal at high speed, finally obtaining a high-speed, high-quality optical signal.

[0045] Example 2: A method for fabricating a temperature-compensated optical emission link packaging structure includes the following steps:

[0046] 1) Fabrication of semiconductor optical amplifier: The semiconductor optical amplifier uses InP-based material, and a quantum well structure is grown by MOCVD and then flip-chip bonded to a silicon substrate.

[0047] 2) Fabrication of LRSPP Coupler: The wedge-shaped structure of the LRSPP coupler is fabricated on the silicon substrate by electron beam lithography and reactive ion etching, ensuring connection with the semiconductor optical amplifier, and optimizing the wedge angle and length;

[0048] 3) Microring resonator and Bragg grating reflector: Made of silicon or AZO, fabricated on a silicon substrate by nanoimprinting and etching to ensure that the microring of the microring resonator and the microring resonator modulator have the same structure and material, and to ensure that the microring resonator is connected to the LRSPP coupler and the Bragg grating reflector through the first direct waveguide.

[0049] 4) Fabrication of a micro-ring resonator modulator for the modulation link: Using silicon or AZO as the material, it is fabricated on a silicon substrate by nanoimprinting and etching, and it is ensured that it can be connected to the LRSPP coupler through the second straight waveguide. The second port of the fabricated micro-ring resonator modulator is connected to the third straight waveguide as the optical output port. The first, second and third straight waveguides are kept parallel.

[0050] 5) The semiconductor optical amplifier, LRSPP coupler, micro-ring resonator, Bragg grating reflector and modulation link fabricated on the silicon substrate in steps 1)-4) are integrated onto the packaging substrate using micro-nano processes to complete the optical link packaging.

[0051] The performance of the temperature-compensated optical emission link packaging structure prepared above was verified:

[0052] The output eye diagram and spectrum of the uncompensated optical emission link were tested at 20℃ and 60℃: the eye diagrams were clear with good opening, and the wavelength shift of the spectral peaks was synchronized, proving that high-quality signal output over a wide temperature range can still be achieved without temperature control. Figure 4-8 As shown.

[0053] Figure 4 The spectral relationship between the microring resonator and the BGR is shown. The relationship between the reflection bandwidth and reflectivity of the BGR and the resonant wavelength of the microring resonator needs to meet certain requirements. The reflection spectrum of the BGR needs to be reflected by the resonant peak of the microring resonator modulator to achieve wavelength feedback.

[0054] Figure 5The output power of the integrated light source under different coupling losses is shown. In actual manufacturing, due to manufacturing errors, material issues, and other factors, there is a certain gap between the actual and theoretical losses. The coupling loss C between the SOA and the silicon waveguide (the insertion loss of the LRSPP coupler) has a significant impact on the performance of this integrated light source. Therefore, based on the LI (Light-Current) characteristics of semiconductor lasers, the variation of the output power of this integrated light source under different coupling losses C is analyzed and studied. The analysis results are as follows: Figure 5 As shown in Figure 5, the smaller the coupling loss C, the smaller the threshold current of the integrated light source, the higher the photoelectric conversion efficiency, and the greater the output power. The coupling loss C not only affects the output power of the integrated light source, but also affects the external quantum efficiency of the light source.

[0055] Figure 6 This represents the shift of the center wavelength of the microring resonator at different temperatures. Optical transmitter links contain power devices—semiconductor lasers or SOAs—and are typically packaged together with other power devices. Therefore, the operating temperature of the optical transmitter link is not constant in practice. Due to the thermo-optic effect, the refractive index of the material changes with temperature. The center wavelength shift of the microring resonator... Relationship with operating temperature as follows Figure 6 As shown by the solid line, the microring resonator consists of four layers: silicon, indium tin oxide, silicon dioxide, and silver. Because the thermo-optical coefficient of SiO2 is only 0.62 × 10⁻⁶, the microring resonator is designed to withstand these conditions. / K, and the thermo-optical coefficient of Si is much greater than that of AZO and SiO2. Therefore, the change in the effective refractive index of the microring waveguide is mainly caused by the change in the refractive index of the Si material. Specifically, a 1℃ increase in the optical link temperature shifts the center resonant wavelength of the microring resonator by 0.0452 nm, i.e. / ΔT = 0.0452 nm / ℃. Since the BGR needs to reflect the resonant peak of the microring resonator, the reflection spectrum of the BGR must still include the resonant peak of the microring resonator even after the resonant wavelength of the microring resonator changes. This is to ensure that the wavelength excited by the integrated light source is the same as the resonant wavelength of the microring resonator modulator. The center wavelength shift of the BGR's reflection spectrum varies with the operating temperature as follows: Figure 6 As shown by the dashed line. BGR's / ΔT=0.0475 nm / ℃, although BGR and microring resonator / ΔT is inconsistent, but because the resonance peak of the microring resonator is within the reflection window of the BGR and has a certain margin, even though the BGR and the microring resonator are not identical, the resonance peak of the microring resonator is within the reflection window of the BGR and has a certain margin. Although / ΔT differs, it can still achieve the corresponding spectral reflection effect over a wide range of temperature variations.

[0056] Figure 7 The output power of the integrated light source is shown in Figure 7 at different temperatures. Since the micro-ring resonator and the micro-ring resonant modulator are identical in structure and materials, their Δλ / ΔT ratios are the same. Therefore, when the optical link temperature changes, their resonant wavelength changes with temperature in a consistent manner, ensuring that the central oscillation wavelength of the integrated light source remains consistent with the resonant wavelength of the micro-ring modulator. The output spectrum of the light source in the optical transmitter link at different temperatures is shown in Figure 7. The oscillation wavelength of the integrated light source increases with increasing temperature, and the shift in resonant wavelength is essentially consistent with the shift in the micro-ring resonator. Specifically, for every 1°C increase in the operating temperature of the optical transmitter link, the oscillation wavelength of the light source shifts by 0.0455 nm, i.e., Δλ / ΔT = 0.0455 nm. This analysis also proves that the oscillation wavelength of the light source is jointly determined by the micro-ring resonator and the BGR, and that the oscillation wavelength of the integrated light source in the optical transmitter link can be adapted to the resonant wavelength of the micro-ring modulator without a temperature compensation structure.

[0057] Figure 8 Eye diagrams of the output signal of the optical transmitter link at different temperatures: (a) 20℃, (b) 60℃. To verify the effectiveness of this scheme in matching the operating wavelength of the light source and modulator without the need for a temperature control device, the modulation performance of the optical transmitter link was studied and analyzed. At a data transmission rate of 50 Gb / s and optical transmitter link temperatures of 20℃ and 60℃, the output eye diagrams of the modulation signal of the optical transmitter link are as follows: Figure 8 As shown in the diagram, the output signal eye diagram analysis results show that the signal output quality does not change significantly, whether at room temperature or when the optical transmitter link experiences a significant temperature rise. This analysis also proves that the optical transmitter link can achieve high-quality signal output without a temperature compensation device.

[0058] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A temperature-compensated optical emission link packaging structure, characterized in that, The device includes a semiconductor optical amplifier, an LRSPP coupler, a first straight waveguide, a second straight waveguide, a microring resonator, and a Bragg grating reflector. The first port of the LRSPP coupler is connected to the output port of the semiconductor optical amplifier, the second port of the LRSPP coupler is connected to the first straight waveguide, the first straight waveguide is connected to the first port of the microring resonator, the second port of the microring resonator is connected to the Bragg grating reflector, and the third port of the LRSPP coupler is connected to the second straight waveguide, which serves as the optical output. The semiconductor optical amplifier has a high-reflectivity mirror. The semiconductor optical amplifier, LRSPP coupler, first straight waveguide, second straight waveguide, microring resonator, and Bragg grating reflector constitute an external cavity semiconductor laser, which outputs light in a waveguide parallel coupling manner.

2. The temperature-compensated optical emission link packaging structure according to claim 1, characterized in that, It also includes a modulation link, which is connected to a second straight waveguide that serves as the optical output, for modulation and high-speed transmission of the output optical signal.

3. The temperature-compensated optical emission link packaging structure according to claim 1, characterized in that, The modulation link includes a microring resonator modulator and a third straight waveguide. The first port of the microring resonator modulator is connected to the second straight waveguide, and the second port of the microring resonator modulator is connected to the third straight waveguide. The microring resonator modulator has the same structure and materials as the microring resonator.

4. The temperature-compensated optical emission link packaging structure according to claim 1, characterized in that, The LRSPP coupler uses an LRSPP wedge coupler.

5. The temperature-compensated optical emission link packaging structure according to claim 3, characterized in that, The semiconductor optical amplifier, LRSPP coupler, first straight waveguide, second straight waveguide, micro-ring resonator, Bragg grating reflector, micro-ring resonator modulator and third straight waveguide are integrated and packaged on a silicon substrate using micro-nano technology.

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