Film optical filter for 1.6 T optical module

Abstract

The utility model relates to the technical field of optical films, in particular to a film optical filter for a 1.6 T optical module, which comprises a glass substrate, two sides of the glass substrate are respectively plated with a high-reflective film and an antireflection film, the high-reflective film comprises at least n first high-refractive-index film layers and at least n first low-refractive-index film layers, the film layer attached to the glass substrate layer is a first high-refractive-index film layer, and the first high-refractive-index film layer and the first low-refractive-index film layer are sequentially and alternately stacked in the direction away from the glass substrate layer, so that the transmission isolation degree of the high-reflective film is larger than-30 DB, and the reflection insertion loss is smaller than-0.15 DB; the antireflection film comprises at least m second high-refractive-index film layers and at least m second low-refractive-index film layers, and the film layer attached to the glass substrate layer is the second high-refractive-index film layer; n is a natural number greater than or equal to 120, and m is 1 or 2. Therefore, the performance and the quality of the thin film optical filter are improved, and the thin film optical filter can be better suitable for a 1.6 T optical module.

Description

TECHNICAL FIELD

[0001] The utility model relates to optical film technical field, concretely relates to a film filter for 1.6T optical module. BACKGROUND

[0002] In the field of optical communication, with the continuous improvement of data transmission rate, 1.6T optical module as the representative of the new generation of high-speed transmission technology is gradually becoming the key component in the field of data center, cloud computing and high-performance computing. As one of the core elements in the optical module, the performance of the film filter directly affects the transmission quality, bandwidth utilization and system stability of the optical signal.

[0003] Currently, there are still some significant defects in the film filter technology for 1.6T optical module, which restricts its further development and application. In the prior art, the film filter usually adopts a multi-layer dielectric film structure, which realizes the transmission, reflection or absorption of specific wavelength optical signals by accurately controlling the thickness and refractive index of each layer. In 1.6T optical module, the film filter is mainly used to filter out unwanted stray light to ensure the purity and stability of the optical signal during transmission. In addition, the film filter also needs to have good temperature stability, mechanical strength and environmental adaptability to cope with complex and variable operating environments.

[0004] After testing the film filter in the prior art, the following defects are found:

[0005] 1. Bandwidth limitation: the current film filter technology has certain limitations in bandwidth. With the improvement of 1.6T optical module transmission rate, the requirement for filter bandwidth is also getting higher and higher. However, the traditional multi-layer dielectric film structure faces technical bottleneck in widening the bandwidth, which is difficult to meet the demand of higher rate transmission. This may cause distortion or attenuation of optical signal during transmission, affecting system performance.

[0006] 2. Temperature sensitivity: the performance of the film filter is easily affected by temperature. In high temperature or low temperature environment, the refractive index, thickness and other parameters of the filter may change, causing the filter characteristic to deviate. This temperature sensitivity limits the application of 1.6T optical module in extreme environmental conditions. Although some technologies use special materials or design to reduce temperature sensitivity, the effect is still not ideal.

[0007] 3. Complex preparation process: the preparation of high-performance film filter requires high-precision preparation process and equipment. In the current technology, the deposition, etching and other process steps of multi-layer dielectric film are complicated and require high precision, which increases the production cost and manufacturing difficulty. In addition, there may be problems such as uneven film layer and defects in the preparation process, which affect the quality and service life of the filter.

[0008] 4. Lack of standardization: There are many different specifications and performance of thin film filter products on the market at present, but there is a lack of unified standards and specifications. This increases the difficulty of selection and use of users, and may cause compatibility problems between different products.

[0009] Therefore, the current thin film filter technology for 1.6T optical modules has obvious defects in bandwidth, temperature sensitivity, preparation process, etc. In order to overcome these defects and promote the development of optical communication technology, it is also necessary to optimize and improve the structure of the current thin film filter to improve the performance and quality of the thin film filter. Practical new type content

[0010] The purpose of the present application is to provide a thin film filter for a 1.6T optical module to improve the performance and quality of the thin film filter, so that it can be better applied to a 1.6T optical module.

[0011] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0012] A thin film filter for a 1.6T optical module, comprising a glass substrate, a high reflection film and an anti-reflection film are respectively plated on both sides of the glass substrate, the high reflection film comprises at least n first high refractive index film layers and at least n first low refractive index film layers, wherein the film layer attached to the glass substrate is a first high refractive index film layer, the first high refractive index film layer and the first low refractive index film layer are sequentially and alternately stacked in the direction away from the glass substrate, so that the transmission isolation of the high reflection film is greater than -30DB, and the reflection insertion loss is less than -0.15DB;

[0013] The anti-reflection film comprises at least m second high refractive index film layers and at least m second low refractive index film layers, wherein the film layer attached to the glass substrate is a second high refractive index film layer, the second high refractive index film layer and the second low refractive index film layer are sequentially and alternately stacked in the direction away from the glass substrate;

[0014] Wherein, n is a natural number greater than or equal to 120, and m is 1 or 2.

[0015] In a preferred design, the material of the first high refractive index film layer is TA2O5; the material of the first low refractive index film layer is SiO2.

[0016] In a preferred design, the film layer thickness of the first high refractive index film layer is 154.5±10, unit nm; the film layer thickness of the first low refractive index film layer is 221.13±10, unit nm.

[0017] In a preferred design, the material of the second high-refractive-index film layer is TA2O5; and the material of the second low-refractive-index film layer is SiO2.

[0018] In a preferred design, the film layer thickness of the second high-refractive-index film layer is 38.65±10 nm; and the film layer thickness of the second low-refractive-index film layer is 197.55±10 nm.

[0019] In a preferred design, the central wavelength λ of the thin-film optical filter ranges from 1250 nm to 1360 nm, and the passband bandwidth is greater than 3 nm.

[0020] By introducing a temperature compensation mechanism into the thin-film optical filter, i.e., using a material with a negative temperature coefficient (low-refractive-index film layer) in combination with a material with a positive temperature coefficient (high-refractive-index film layer), this combination can automatically adjust the optical properties of the filter when the temperature changes, offsetting the performance deviation caused by temperature fluctuations.

[0021] Through the above-mentioned technology, the 1.6T optical module thin-film optical filter not only solves the problems of bandwidth limitation and temperature sensitivity existing in the prior art, but also greatly improves the overall performance. Specifically, 1) the filter can provide a wider transmission bandwidth and a flat transmission curve, effectively reducing the distortion and attenuation of optical signals during transmission. 2) The temperature compensation mechanism and the application of high-stability materials enable the filter to maintain good working conditions under extreme temperature conditions, expanding its application scenarios. 3) Although the multilayer film structure has a multilayer structure, through simulation optimization and selection of appropriate materials, the complexity and cost of the preparation process can be reduced, while the product yield and service life can be improved. Thus, the thin-film optical filter can effectively promote the rapid development of data centers, cloud computing, and high-performance computing. BRIEF DESCRIPTION OF DRAWINGS

[0022] Fig. 1 A structure schematic view of the thin-film optical filter for a 1.6T optical module provided by the present application in an embodiment;

[0023] Fig. 2 A layer structure schematic view of the high-reflection film in the thin-film optical filter for a 1.6T optical module provided by the present application in an embodiment;

[0024] Fig. 3 A coating curve diagram of the thin-film optical filter for a 1.6T optical module provided by the present application.

[0025] LEGEND:

[0026] 1-glass substrate, 2-high reflection film, 21-first high-refractive-index film layer, 22-first low-refractive-index film layer, 3-anti-reflection film. Detailed Implementation

[0027] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0028] According to specific embodiments of this disclosure, a thin-film filter for a 1.6T optical module is provided. Figs. 1-3 One specific implementation is shown.

[0029] See Figs. 1-3 As shown, the thin-film filter for a 1.6T optical module includes a glass substrate 1, with a high-reflectivity film 2 and an anti-reflection film 3 deposited on both sides of the glass substrate 1. The high-reflectivity film 2 includes at least n layers of first high-refractive-index film 21 and at least n layers of first low-refractive-index film 22, wherein the film layer attached to the glass substrate 1 is the first high-refractive-index film 21, and the first high-refractive-index film 21 and the first low-refractive-index film 22 are stacked alternately in the direction away from the glass substrate 1, so that the transmission isolation of the high-reflectivity film 2 is greater than -30dB and the reflection insertion loss is less than -0.15dB; the anti-reflection film 3 includes at least m layers of second high-refractive-index film and at least m layers of second low-refractive-index film, wherein the film layer attached to the glass substrate 1 is the second high-refractive-index film, and the second high-refractive-index film and the second low-refractive-index film are stacked alternately in the direction away from the glass substrate 1; wherein n is a natural number greater than or equal to 120, and m is 1 or 2.

[0030] The thin-film filter used in the 1.6T optical module adopts a multi-layer film structure, with a glass substrate 1 as the core and a high-reflection film 2 and an anti-reflection film 3 respectively deposited on both sides. By precisely controlling the thickness and refractive index of each film, it can achieve efficient transmission, reflection or absorption of light signals of specific wavelengths, thereby ensuring the purity and stability of the light signal during transmission.

[0031] The high-reflectivity coating 2 consists of at least n first high-refractive-index film layers 21 and at least n first low-refractive-index film layers 22, where n is a natural number greater than or equal to 120. The layer closest to the glass substrate 1 is the first high-refractive-index film layer 21, and then, along the direction away from the glass substrate 1, the high-refractive-index film layers and low-refractive-index film layers are alternately stacked. Through this multilayer film structure, the high-reflectivity coating 2 has high isolation, achieving extremely high transmission isolation (>-30dB) while maintaining very low reflection insertion loss (<-0.15dB), enabling the high-reflectivity coating 2 to effectively block unwanted light signals while minimizing the energy loss of useful light signals.

[0032] The antireflection coating 3 consists of at least m second high-refractive-index layers and at least m second low-refractive-index layers, where m is 1 or 2. Similar to the high-reflection coating 2, the layer closest to the glass substrate 1 is the second high-refractive-index layer, and thereafter, high-refractive-index and low-refractive-index layers are alternately arranged in the direction away from the glass substrate 1. In this way, the reflection loss of incident light at the interface can be minimized, the transmission efficiency of the optical signal can be improved, and thus the intensity and quality of the optical signal can be guaranteed not to be affected.

[0033] By introducing a temperature compensation mechanism into thin-film filters, that is, by combining materials with negative temperature coefficients (low refractive index films) with materials with positive temperature coefficients (high refractive index films), this combination can automatically adjust the optical properties of the filter when the temperature changes, thus offsetting the performance deviation caused by temperature fluctuations.

[0034] Through the aforementioned technologies, this 1.6T optical module thin-film filter not only solves the problems of bandwidth limitations and temperature sensitivity existing in current technologies, but also significantly improves its overall performance. Specifically: 1. The filter provides a wider transmission bandwidth and a flatter transmission curve, effectively reducing distortion and attenuation of the optical signal during transmission. 2. The temperature compensation mechanism and the application of highly stable materials enable the filter to maintain good operating performance under extreme temperature conditions, expanding its application scenarios. 3. Although this multilayer film structure has multiple layers, through simulation optimization and the selection of suitable materials, the complexity and cost of the manufacturing process can be reduced, while improving the product yield and lifespan. Therefore, this thin-film filter can powerfully promote the rapid development of data centers, cloud computing, and high-performance computing.

[0035] In a specific embodiment of this disclosure, the material of the first high refractive index film layer is TA2O5; the material of the first low refractive index film layer is SiO2.

[0036] Ta₂O₅ (tantalum pentoxide), as a high-refractive-index material, possesses excellent optical transparency and mechanical strength, offering a high refractive index (around 2.1) in the visible and near-infrared bands. Furthermore, it exhibits good chemical stability and is not easily affected by moisture and air. SiO₂ (silicon dioxide), as a low-refractive-index material, has a relatively low refractive index (around 1.46) and possesses excellent thermal stability and chemical inertness. In addition, SiO₂ is easily deposited into uniform and dense thin films, contributing to improved overall performance of high-reflectivity films. This results in thin-film filters with superior optical performance, significantly broadening the filter's operating bandwidth and demonstrating excellent stability and reliability in practical applications.

[0037] In one embodiment provided in this disclosure, the thickness of the first high-refractive-index film layer 21 is 154.5 ± 10 nm, and the thickness of the first low-refractive-index film layer 22 is 221.13 ± 10 nm. This helps improve the thermal stability and chemical inertness of the high-reflectivity film 2, and facilitates its deposition into a uniform and dense film, thus improving the overall performance of the high-reflectivity film 2. This allows the high-reflectivity film 2 to achieve extremely high transmission isolation (> -30 dB) while maintaining very low reflection insertion loss (< -0.15 dB), enabling it to effectively block unwanted optical signals while minimizing energy loss of useful optical signals. Therefore, this thin-film filter for a 1.6T optical module not only solves the problems of bandwidth limitations and temperature sensitivity in the prior art, but also significantly improves its overall performance.

[0038] It should be noted that controlling the thickness error of each film layer to within ±10 nm can achieve more ideal transmission and reflection characteristics, thereby improving the quality and transmission efficiency of optical signals.

[0039] In this disclosure, the material of the second high refractive index film layer is TA2O5; the material of the second low refractive index film layer is SiO2, thereby improving the thermal and chemical stability of the high reflectivity film, enabling the thin film filter to have excellent optical performance, significantly broadening the working bandwidth of the filter, and exhibiting excellent stability and reliability in practical applications.

[0040] In one embodiment provided in this disclosure, the thickness of the second high refractive index film is 38.65±10 nm; and the thickness of the second low refractive index film is 197.55±10 nm.

[0041] By controlling the thickness variation of each film layer within ±10 nm, more ideal transmission and reflection characteristics can be achieved, thereby improving the quality and transmission efficiency of optical signals. Simultaneously, by employing high-precision, low-cost fabrication techniques such as magnetron sputtering and ion-assisted deposition, the film thickness can be controlled within this range. This simplifies the fabrication process, improving efficiency and yield. Furthermore, it minimizes reflection losses at the interface, enhancing optical signal transmission efficiency and ensuring that the intensity and quality of the optical signal remain unaffected. This guarantees that the thin-film filter maintains high efficiency and stable performance in high-speed data transmission, meeting the ever-growing demands of modern communication systems.

[0042] In one embodiment provided in this disclosure, the center wavelength λ of the thin-film filter is in the range of 1250~1360nm, and the passband bandwidth is greater than 3nm.

[0043] With a center wavelength λ of 1250–1360 nm, it can cover the adjacent region of the C-band (approximately 1530–1565 nm), making it suitable for various fiber optic communication standards and effectively supporting high-speed data transmission. A passband bandwidth greater than 3 nm is beneficial for better adapting to the spectral characteristics of different light sources, ensuring stable optical performance across the entire operating wavelength range. This results in excellent optical performance for the thin-film filter, exhibiting outstanding stability and reliability. It ensures that the optical module maintains efficient and stable performance during high-speed data transmission, meeting the ever-growing demands of modern communication systems.

[0044] The table below shows the optical specifications of the thin-film filter used in the 1.6T optical module in this application.

[0045]

[0046] In the preferred embodiment provided in this disclosure, the high-reflectivity film is composed of 126 layers of first high-refractive-index film and 126 layers of first low-refractive-index film stacked alternately. The first layer is a first high-refractive-index film (tantalum pentoxide reflective dielectric layer) and is attached to the surface of the glass substrate. The second layer is a first low-refractive-index film (silicon dioxide reflective dielectric layer). Following the direction away from the glass substrate, odd-numbered layers are high-refractive-index films, and even-numbered layers are low-refractive-index films. The antireflective film includes one second high-refractive-index film and one first low-refractive-index film. The first layer is a second high-refractive-index film (tantalum pentoxide reflective dielectric layer) and is attached to the surface of the glass substrate. The second layer is a second low-refractive-index film (silicon dioxide reflective dielectric layer) and is attached to the second high-refractive-index film.

[0047] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A thin-film filter for a 1.6T optical module, comprising a glass substrate, wherein a high-reflectivity film and an anti-reflection film are respectively deposited on both sides of the glass substrate, characterized in that, The high-reflectivity film includes at least n first high-refractive-index film layers and at least n first low-refractive-index film layers, wherein the film layer attached to the glass substrate is the first high-refractive-index film layer, and the first high-refractive-index film layer and the first low-refractive-index film layer are stacked alternately in a direction away from the glass substrate, so that the transmission isolation of the high-reflectivity film is greater than -30dB and the reflection insertion loss is less than -0.15dB; The antireflective coating includes at least m layers of second high refractive index film and at least m layers of second low refractive index film, wherein the film layer attached to the glass substrate is the second high refractive index film layer, and the second high refractive index film layer and the second low refractive index film layer are stacked alternately in a direction away from the glass substrate; Where n is a natural number greater than or equal to 120, and m is 1 or 2.

2. The thin-film filter for a 1.6T optical module according to claim 1, characterized in that, The material of the first high refractive index film is TA2O5; the material of the first low refractive index film is SiO2.

3. The thin-film filter for a 1.6T optical module according to claim 1, characterized in that, The thickness of the first high refractive index film is 154.5±10 nm; the thickness of the first low refractive index film is 221.13±10 nm.

4. The thin-film filter for a 1.6T optical module according to claim 1, characterized in that, The material of the second high refractive index film is TA2O5; the material of the second low refractive index film is SiO2.

5. The thin-film filter for a 1.6T optical module according to claim 1, characterized in that, The thickness of the second high-refractive-index film is 38.65±10 nm; the thickness of the second low-refractive-index film is 197.55±10 nm.

6. The thin-film filter for a 1.6T optical module according to claim 1, characterized in that, The center wavelength λ of the thin-film filter is in the range of 1250~1360nm, and the passband bandwidth is greater than 3nm.

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