TW520447B - Interference filter - Google Patents

Abstract

An interference filter is formed on a substrate. The substrate has a plurality of reflective mirror layers and a plurality of space layers alternatively stacked with the reflective mirror layers to form a plurality of chambers, wherein each chamber is composed of two reflective mirrors and a space layer. Each reflective mirror layer is formed by alternatively stacking a plurality of high reflective index layers and a plurality of low reflective index layers. The present invention utilizes a film of fixing titanium oxides and silicon oxides with different ratios as the material of the high reflective index layer in the reflective mirror for replacing the conventional Ta2O5 material, so as to make high reflective index layer have a larger reflective index, thereby making the light signal penetrating the interference filter have a narrower bandwidth. In addition, it is able to reduce the number of layers in plating films by increasing the difference between the high and low reflective indices.

Description

520447 3862twadf.doc / 006 A7 B7 V. Description of the invention (f) The present invention relates to an interference filter ', and more particularly to a Dense Wavelength Division Multiplexer (DWDM). Narrow band pass thin film interference filter. Due to the growth of the Internet and the increasing demand for network bandwidth, fiber-optic networks are increasingly developing in terms of large capacity, variety, high reliability, and economic benefits. Among them, the high-density multi-wave duplexer is one of the most important passive components in optical fiber communication. Its basic function is to use the principle of splitting / multiplexing to allow different wavelength signals to be transmitted in the same optical fiber. The use of a high-density multi-wavelength divider can increase the communication transmission capacity of a single fiber by a factor of multiples. This shows the importance of high-density multi-wavelength dividers in high-speed and high-capacity communication transmission systems. In addition, the principle of high-density multi-wavelength divider can be divided into various types, including thin-film interference filters, fiber gratings, and arrayed waveguides. The high-density multi-wavelength-wave divider interference filtering currently formed by coating methods The film is the most thermally stable and the most popular in the market. Generally, the material of the mirror layer in the thin-film interference filter in the high-density multi-wavelength divider uses Ta205 or Ti02 with a high refractive index as the material of the high refractive index layer, and Si02 or Al2 03 with a low refractive index as the low Refractive index layer materials are stacked on top of each other (approximately 20 to 25 layers). It is known that in the production process of thin film interference filters, in order to achieve a more ideal transmission frequency band, it is necessary to make at least three cavity structure interferences. Filter, each cavity is composed of two mirror layers and one space layer. As for the three cavity structure (four mirror layers and three space layers), the required plating is 3 CNS) A4 size (210 X 297 mm) (Please read the note on the back? Matters before filling out this page) > · IBM · V ·· MB I Xin MM. Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs and Consumer Cooperatives 520447 3 862twadf.doc / 006 A7 B7 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. 5. The description of the invention (2) The number of coatings is nearly one hundred layers, which makes the process very complicated, the film thickness monitoring is not easy, and the yield is extremely low. Leads to increased production costs, and its penetration of the best bandwidth can do 1~2nm, the more narrow and more difficult to make, the lower the yield. In DWDM applications, narrow bandwidth and multi-channel are the development trend of broadband network communications. The current technological level of thin-film interference filters has formed a bottleneck for further development. Therefore, thin-film interference filters with narrower bandwidths must be developed to meet the needs of future DWDM technologies. Therefore, the purpose of the present invention is to provide a silicon oxide material doped with a certain proportion of titanium oxide as a high refractive index material, and alternately stacked with a low refractive index material such as Si02 or ai2o3 to form a reflective mirror layer in an interference filter. In order to reduce its optical absorption, increase its reflectivity, and reduce the number of layers required for coating, the transmission spectrum of the thin-film interference filter has a narrower band width. In order to achieve the above object of the present invention, a dry filter system structure is proposed on a substrate. The substrate has a plurality of mirror layers and a plurality of space layers stacked alternately to form a plurality of cavities, wherein each cavity system is formed by It consists of two reflection layers and a space layer. Each mirror layer is formed by alternately stacking multiple layers of high refractive index layers and multiple layers of low refractive index layers. In the present invention, a mixed film of titanium oxide and silicon oxide in various proportions is used as the material of the high refractive index layer in the reflector, and the conventional Ta205 material is replaced, so that the high refractive index layer has a higher refractive index, thereby making The optical signal that penetrates the interference filter has a narrower bandwidth to increase the number of channels for DWDM communication. In addition, the number of layers required for coating can be reduced by increasing the difference between high and low refractive index. 4 This paper size applies to China National Standard (CNS) A4 specification (21〇 X 297 meals) (Please read the precautions on the back before filling this page)

520447 3862twaci ^ * ^ OC / Ο Ο 6 Α7 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. 5. The description of the invention (3) is _ the above-mentioned objects, features, and advantages of the present invention can be more clearly understood. The example, combined with the attached drawings, will be described in detail as follows: 81 Wuzhi's brief description: The first plot shows that the optical extinction coefficients of individual optical films and Figure of experimental data between the two annealing temperatures; Figure 2 shows the cut-off wavelength of the optical film at different tO 皿 degrees at various tO2 doping levels. Distribution diagram; Figure 3 shows the relative diffraction intensity ratios of X-rays under different annealing levels of Si02 doped at different annealing temperatures for 24 hours; Figure 4 shows the different diffraction intensity of Si02 Under the doping amount, the surface roughness at different annealing temperatures; and Fig. 5A shows the structure diagram of the surface of the Ti02 optical film without the addition of Si02, and the annealing temperature is 150 ° (: Ti02 optical film; Fig. 5B) In the case of not adding Si02, annealing The temperature is 225 ° (: the structure diagram of the surface of the Ti02 optical film; Figure 5C shows the case where the amount of Si02 added is 17%, and the annealing temperature is 40 (TC of Ti〇rSi〇2 optical hybrid film Surface structure diagram; FIG. 6 shows a structure diagram of a high-density multi-wavelength divider according to a preferred embodiment of the present invention; FIG. 7 shows a high-density multi-wavelength division 5 according to a preferred embodiment of the present invention (please (Please read Note 3 on the back before filling out this page)

This paper size applies to China National Standard (CNS) A4 specification (210 X 297 mm) 520447 3862twadf.d〇c / 〇〇6 1 B7 V. Description of the invention (屮) _ Schematic diagram of interference filter in the machine; Section 8A The figure shows the transmission spectrum of the conventional high refractive index layer with τ ~ 〇5; and (please read the precautions on the back before filling this page) Figures 8B to 8D are shown according to the present invention ~ The preferred embodiment uses various SiO 2 doped mixed films as the transmission spectra of the high refractive index layer. Explanation of the labeling of the drawings: 100: gradient refractive index filters 102, 104, 106, 108: interference filters 110, 112, 114, 116: dry filter 200: substrate 202: cavity 204: highly reflective mirror layer 206: Space layer 208: High-refractive-index layer 210: Low-refractive-index layer Preferred embodiment Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs This embodiment describes an optical hybrid film and a method for manufacturing the same, which have low-loss characteristics. This optical hybrid film is made of titanium oxide as the main material and is doped with a certain proportion of silicon oxide. The optical hybrid film is formed by ion beam sputtering. When light is incident into the hybrid film, the proportion of absorption and scattering is extremely low. The optical hybrid film produced by ion beam sputtering is a small-area silicon wafer attached to a metal titanium sputtering target with a high-temperature-resistant vacuum adhesive, and is sputtered on the synthetic target with an ion beam. It is filled in a coating vacuum chamber. 6 paper sizes are applicable to China National Standard (CNS) A4 (210 X 297 public love). Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. 520447 3862twadf.doc / 〇〇6 pj B7 V. Description of the invention (k) The amount of high-purity argon and oxygen is used as reactive sputtenng to combine the oxygen atoms with the Ti and Si targets which are sputtered to the substrate by argon ions. A mixed film of titanium oxide and silicon oxide is formed on the substrate. Changing the area of the silicon wafer can change the proportion of silicon oxide in the mixed film. In the following, experimental data of thin films made by adding 5%, 9%, and 17% of silicon oxide to titanium oxide and manufactured by ion beam sputtering are used to explain the actual optical hybrid film of the present invention. efficacy. However, the above is not intended to limit the present invention. First, please refer to FIG. 1, which shows the experimental data between the extinction coefficient (k) and the annealing temperature (° C) of the mixed film. The extinction coefficient is a single order of magnitude of HT4. From the theory of electromagnetic waves, the thin film has a complex refractive index (N), N = n + jk. η is generally called the refractive index, and k is the extinction coefficient. The transmission intensity of the electromagnetic wave is proportional to the square of the absolute value of exp (j (2TTNx / A)). Substituting N = n + jk for ’produces an attenuation term exp (-4 7Γ · kx / λ). This term indicates that the intensity of an electromagnetic wave incident on a medium decreases with the path X. The attenuation of the electromagnetic wave intensity is due to the absorption and scattering of the electromagnetic wave by the medium. The extinction coefficient k indicates the degree of absorption and scattering of the electromagnetic wave by the medium. Therefore, we hope that the smaller the extinction coefficient k is, the better. Figure 1 shows that the extinction coefficient of the hybrid film decreases as the proportion of silicon oxide in the hybrid film increases. And the extinction coefficient increases sharply at a certain temperature due to the scattering caused by the generation of polymorphism, and this temperature increases as the proportion of silicon oxide increases. 7 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) (Please read the precautions on the back before filling this page). ---- 520447 3862twadf.doc / 006 A7 B7 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. 5. Description of the invention (hand) From the figure of the younger brother, it can be seen that when Si〇2 is not added (that is, the curve of 0%) When the annealing temperature reaches 200 ° C, the extinction coefficient k rises sharply, which means that the pure Ti02 film can only withstand an annealing temperature of about 200 ° C. Secondly, when the amounts of SiO2 added to the Ti〇2 film are 5%, 9%, and 17%, the corresponding maximum withstand annealing temperatures are about 250 ° C, 300 ° C, and 450 ° C, respectively. . Therefore, it can be seen that the more Si02 added, the higher the annealing temperature it can withstand. Therefore, the optical hybrid film can withstand higher annealing temperatures and has a lower extinction coefficient, that is, lower optical absorption and optical scattering. It can be seen from Figure 1 that when the more Si02 is added, such as 17%, the extinction coefficient k of the 1 ^ 02-3 丨 02 optical hybrid film reaches the highest annealing temperature before the explosion, k Is about lx 10 · 4, so we know that the optical hybrid film has excellent transparency. In summary, as the amount of Si02 added is greater, the transparency of the Ti02-Si02 optical hybrid film is higher, and absorption and scattering are less likely to occur. Next, please refer to FIG. 2, which shows the distribution graphs of the cut-off wavelength (λ c) of the optical film under different SiO 2 doping amounts and different annealing temperatures. Cut-off wavelength refers to the lowest wavelength that can be transmitted after the film is deposited. Laser light below λ c cannot penetrate the film (zero transmittance). Therefore, the cut-off wavelength λ c can be used as an indicator of the absorption of optical films. The smaller the cut-off wavelength, the smaller the absorption. The experimental results are shown in the figure without adding, and when adding 5%, 9%, and 17%. In the figure, the horizontal axis represents the annealing temperature, and the vertical axis represents the cutoff wavelength Ac distribution of the optical film. It can be seen from Fig. 2 that the curve system decreases with the increase of the annealing temperature, which shows that high temperature annealing can reduce the absorption. Add 8 paper sizes to the Chinese National Standard (CNS) A4 (210 X 297 mm) (please read the note on the back? Matters before filling this page)

520447 3862twadf.doc / 006 A7 B7 V. Description of the invention (q) 5%, 9% and 17%, it can be seen that the larger the Si02 doping amount, the lower the cutoff wavelength of the optical hybrid film 'That is, the lower the absorption of the optical hybrid film. (Please read the note on the back? Matters before filling out this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. Then please refer to Figure 3, which shows the different S: i02 doping levels and different annealing. The relative diffraction intensity ratio of X-rays after the annealing process is performed at a temperature for 24 hours. This is the crystalline (101) diffraction peak of Ti02 anatase (anatase). Wherein 10 indicates the X-ray diffraction intensity when completely crystallized. The more crystalline components in the film, the stronger the relative diffraction intensity of its X-rays. The experimental results are plotted in the figure without and with SiO2 doping amounts of 5%, 9%, and 17%. In the figure, the horizontal axis represents the annealing temperature, and the vertical axis represents the X-ray relative diffraction intensity of the mixed film. It can be seen from Fig. 3 that when Si02 is not added, when the annealing temperature reaches 200 ° C, the diffraction intensity of X-rays starts to increase sharply. In the case of adding 5%, 9%, and 17% of 3, 02, respectively, the annealing temperature is about 250 ° C, 300 ° C, and 450 ° C, respectively, which corresponds to the X-ray of the optical hybrid film. Diffraction intensity just started to get stronger. Therefore, from the above experimental results, it is known that when the Si02 doping amount is larger, the relative diffraction intensity of the X-ray of the optical hybrid film starts to increase at a higher annealing temperature, that is, when the Si02 doping amount is larger, The higher the crystallization temperature of the thin film, this is consistent with the result of the extinction coefficient. Next, please refer to FIG. 4, which shows the surface roughness at different annealing temperatures under different doping amounts of SiO 2. The experimental results of SiO2 doping and 5%, 9%, and 17% doped SiO2 doping are plotted in the figure. In the figure, the horizontal axis represents the annealing temperature, and the vertical axis represents the light. 9 The paper size is applicable to the Chinese National Standard (CNS) A4 specification (2) 0 X 297 mm. 520447 862twadf.doc / 006 A7 B7 V. Description of the invention (f ) Learn the surface roughness of the film. It can be seen from Fig. 4 that when the material is not added, when the annealing temperature reaches 200 ° C, the surface starts to roughen sharply. With the addition of 5%, 9%, and 17% of SiO2, respectively, the surfaces of the corresponding optical hybrid films begin to become rough at the annealing temperatures of about 250 ° C, 300 ° C, and 450 ° C, respectively. Therefore, from the above experimental results, it is known that the larger the Si02 doping amount, the higher the tempering temperature that the surface flatness of the optical hybrid film can withstand, that is, the more stable the surface flatness of the optical hybrid film, The less likely that surface scattering will occur. Please refer to FIG. 5A, FIG. 5B, and FIG. 5C at the same time. Figures 5A and 5B show the atomic force microscope (AFM) structure diagrams of the surface of a pure Ti02 optical film with annealing temperatures of 150 ° C and 225 ° C, respectively, without the addition of Si02. At 150 ° C, the surface of the TiO2 optical film is flat. At an annealing temperature of 225 ° C, the Ti02 film has undergone a phase transition from an amorphous state to a crystalline state, and the surface becomes rough due to the generation of crystalline particles. Fig. 5C shows a microscope structure diagram of the AFM of a Ti0rSi02 optical hybrid film with an annealing temperature of 400 ° C when the amount of Si02 is 17%. Figure 6C clearly shows that the mixed film doped with 17% silicon oxide can still maintain a flat surface at 400 ° C. Figures 1 to 5A, 5B, and 5C show that the mixed film doped with silicon oxide has lower optical absorption than the pure titanium oxide film doped with silicon oxide, and can withstand higher annealing. It does not crystallize at temperature and maintains a high degree of flatness on the surface, so it has low optical scattering. Therefore, the optical hybrid film of this embodiment has low optical loss and has characteristics of low scattering and low absorptivity. The proportion of silicon oxide added here is not limited. The paper size applies the Chinese National Standard (CNS) A4 (210 X 297 mm) (Please read the precautions on the back before filling this page) 1 > · 1 IV n ϋ 1 · —One OJ · 1— 1 · ϋ ϋ 1 1 »< Printed by the Employees' Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 520447 3862twadf.doc / 006 A7 B7 5. Added to the description of the invention (C |) The greater the amount of ZnO, the higher the annealing temperature the film can withstand, and the lower the ratio of the relative incident light absorbed and scattered. Therefore, it can be known from the above data that the present invention uses titanium oxide and silicon oxide as the material of the interference filter, so that the interference filter has the characteristics of withstanding high annealing temperature and low loss. At present, the use of high-density multi-wavelength-diplexer interference filters ranges from 1525nm to 1570nm. The optical fiber not only has lower absorption loss in this wavelength range, but also can be matched with the high gain band of the EDFA. In such a limited range of use bands, more communication channels must be accommodated, and the interference between each channel must be avoided. The relative requirement is to reduce the bandwidth of each communication channel. The methods of reducing the bandwidth of each communication channel mainly include increasing the reflectivity of the mirror layer in the high-density multi-wavelength division unit, or using increasing the optical thickness of the spacer. Among them, the method of increasing the reflectivity of the mirror layer is, for example, increasing the number of coatings of the mirror layer, or using materials with high and low refractive index differences. Please refer to FIG. 6 at the same time, which is a schematic structural diagram of a high-density multi-wavelength divider according to a preferred embodiment of the present invention. In FIG. 6, the incident light transmitted by a single-film optical fiber diverges the light beam and enters the first interference filter 102 through a gradient refractive index filter 100 (Gradient Index Lens, GRIN Lens). The first interference filter 102 allows only the first The optical signal of the channel passes and reflects other optical signals. The light signal reflected by the first interference filter 102 is incident on the second interference filter 104, and the second interference filter 104 only allows the light signal of the second channel to pass and reflects other light signals. Applicable to China National Standard (CNS) A4 specification (210 X 297 mm) according to the size of the photo paper (Please read the precautions on the back before filling this page) -I · · ϋ Bi- n I n _1 n One: WJ · · ϋ n 11 Bi ·· ϋ ί · ϋ-Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economy 520447 Printed by the Employee Cooperatives of the Intellectual Property Bureau of the Ministry of Economy 3862twadf. doc / 006 V. Description of the invention (10) The same principle, in order The third and fourth interference filters 106, fourth interference filters 108, fifth interference filters 110, sixth interference filters 112, seventh interference filters 114, and eighth interference filters 116 The light signals of channels 5, 5, 6, 7 and 8 are separated. Please refer to FIG. 7, which illustrates a schematic diagram of an interference filter in a high-density multi-wave duplexer according to a preferred embodiment of the present invention. An interference filter is generally constructed on a transparent substrate 200 and includes at least three cavities 202 thereon. Each cavity 202 is composed of two high reflector layers 204 (High Reflector, HR) and a space layer 206 (spacer). The cylindrical mirror layer 204 is formed by alternately stacking a high refractive index layer 208 and a low refractive index layer 210. In the present invention, a mixed film of titanium oxide and silicon oxide is used as the material of the cylindrical refractive index layer 208 in the high-reflection mirror layer 204, and the material of the low refractive index layer 210 between the local refractive index layers 208 is, for example, Si02 Low-refractive-index materials, such as ai2o3, reduce the bandwidth of each channel when the difference between the high-refractive index and the low-refractive index increases. In addition, the thickness of each of the film layers 208, 210 in the above-mentioned high mirror 204 is, for example, a quarter-wavelength optical thickness, the thickness of the space layer 206 is, for example, a half-wavelength optical thickness, and the design wavelength is, for example, 1550nm. However, the thickness of the film layer of the present invention is not limited to a quarter-wavelength optical thickness, the thickness of the space layer 206 is not limited to a half-wavelength optical thickness, and the design wavelength is not limited to 1550 nm. In addition, the titanium oxide and silicon oxide mixed film used in the present invention generally refers to titanium oxide TiOx and silicon oxide SiCC with an atomic ratio of 1 ·· χ, and includes changes in the process parameters of the coating, such as ion Beam spattering process incorporated in this paper size applies to Chinese National Standard (CNS) A * 4 specifications (21〇X 297 public love) (Please read the precautions on the back before filling this page)

520447 862twadf.doc / 006 A7 V. Description of the invention (丨 丨) With different partial pressures of oxygen, all the TiOx & SiOx components obtained. The material of the high-refractive-index layer 208 of the present invention is a mixed film of titanium oxide and silicon oxide, which has a higher refractive index than a conventional material (Ta205), so that the optical signal penetrating the interference filter can be narrower. Bandwidth. In addition, the number of layers required for coating can be reduced by increasing the difference between high and low refractive index. Table 1 shows changes in the refractive index (η) of titanium oxide and silicon oxide according to a preferred embodiment of the present invention for different wavelengths under different doping amounts of SiO2. It can be clearly seen from Table 1 that under various mixing ratios such as 0%, 5%, 9%, and 17% 31%, the doping ratios are higher than the conventional (Ding & 2005). Refractive index. 0% Si02 5% Si02 9% Si02 17% Si02 Ta2〇5 n (550nm) ~ 2.54 ~ 2.52 ~ 2.46 ~ 2.37 ~ 2.20 n (1550nm) ~ 2.40 ~ 2.40 ~ 2.30 ~ 2.20 ~ 2.02

Please refer to FIG. 8A, which shows that the conventional structure using Ta205 as the high refractive index layer is (HL) 6HL6H (LH) 6L (HL) 7HL4H (LH) 7L (HL) 7L (HL) 6HL8H (LH ) Transmission spectrum of 7L. Here Η represents a high refractive index film layer with a quarter-wavelength optical thickness, L represents a low refractive index film layer with a quarter-wavelength optical thickness, (HL) 6 represents 6 pairs of high and low refractive index films, and L6 represents 6 Layer of low refractive index film.

As can be clearly seen from Figure 8A, the interference filter structure is (HL) 6HL6H (LH) 6L (HL) 7HL4H (LH) 7L (HL) 7L (HL) 6HL8H (LH) 7L ------ --------— (Please read the notes on the back before filling out this page) · 1111111 Printed by the Consumers' Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs This paper is compliant with China National Standard (CNS) A'l Specification (210 X 297 mm) 520447 3862twadf.doc / 006 A7 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 5. Description of the invention (α) 'The refractive index of the space layer (ns) is 1.51, the refractive index of the low refractive layer (nL) It is 1.46 and the refractive index (nH) of the Ta205 high refractive index layer is 2.02, and the half-band width (50% bandwidth) of the transmission spectrum is 0.74 nm. Finally, please refer to FIGS. 8B to 8D According to a preferred embodiment of the present invention, it is shown that the conventional Ta205 is replaced by a mixed film with various SiO 2 doped amounts as a high-refractive index layer, and the film structure still maintains the same transmission spectrum. As can be clearly seen from Figure 8B, the structure of the interference filter is (HL) 6HL6H (LH) 6L (HL) 7HL4H (LH) 7L (HL) 7L (HL) 6HL8H (LH) 7L), and its spatial layer The refractive index (ns) is 1.51, the refractive index (nL) of the low refractive index layer is 1.46, and the 17% Si02 doping ratio is used as the high refractive index layer. The refractive index (nH) is 2.2, and the transmission spectrum is obtained. The half bandwidth (50% bandwidth) is 0.18nm. As can be clearly seen from Figure 8C, the structure of the interference filter is (HL) 6HL6H (LH) 6L (HL) 7HL4H (LH) 7L (HL) 7L (HL) 6HL8H (LH) 7L), and its spatial layer The refractive index (ns) is 1.51, the refractive index (nL) of the low refractive index layer is 1.46, the doping ratio of 9% Si02 is used as the high refractive index layer, and the refractive index (nH) is 2.3. The half bandwidth (50% bandwidth) is 0.09nm. As can be clearly seen from Figure 8D, the structure of the interference filter is (HL) 6HL6H (LH) 6L (HL) 7HL4H (LH) 7L (HL) 7L (HL) 6HL8H (LH) 7L), and its spatial layer The refractive index (ns) is 1.51, the refractive index (in) of the low refractive index layer is 1.46, and the doping ratio of 0% or 5% Si02 is used as the high refractive index layer. (Please read the note on the back? Matters before filling out this page ) -I · n ϋ —i · ϋ ϋ n One-by-one mouth 1 · > ϋ ϋ «ϋ I n <

This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 520447 3862twadf.doc / 006 A7 B7 V. Description of the invention (3) The refractive index (nH) is 2.4 The half-band width (50% bandwidth) of the transmission spectrum is 0.05 nm. From Figs. 8A to 8D, it is known that the mixture is doped with 0%, 5%, 9%, and 17% SiO2. As the material of the high refractive index layer, the half-band width of the transmission spectrum is less than the half-band width of the conventional Ta205 material, so it can contain more channels in a limited band range. However, from the previous experimental results, it is known that 0% pure TiO2 film has a very low crystallization temperature, which is likely to cause optical scattering, increase loss and increase bandwidth, but the mixed film doped with SiO2 has a higher crystallization temperature, which can maintain non-crystallization. State, has low optical loss, and can maintain a higher refractive index than Ta205. In summary, the interference filter of the present invention has at least the following advantages: 1. The present invention uses a mixed film of titanium oxide and silicon oxide as the material of the high refractive index layer of the reflective mirror layer in the interference filter to make the reflective mirror The layer has a high reflectance, so the number of layers required for coating the mirror layer can be reduced, thereby simplifying the coating process. 2. In the present invention, a titanium oxide and silicon oxide mixed film is used as the material of the high refractive index layer of the mirror layer in the interference filter. The difference in refractive index between the high refractive index layer and the low refractive index layer is increased, so that the thin film interferes. The transmission spectrum of the filter has a narrower bandwidth, which can effectively increase the number of communication channels. 3. The invention uses a titanium oxide and silicon oxide mixed film as the material of the high refractive index layer of the reflection layer in the interference concentrated wave plate. The structure of the film is amorphous, which makes the interference filter have better temperature stability. 'And lower optical loss. 1 5 This paper size is applicable to China National Standard (CNS) A4 specification ⑵ Gx 297 public love) (Please read the precautions on the back before filling this page) 1 Pack --------- Order i ---- --- Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 520447 3862twadf.doc / 006 A7 B7 Printed by the Consumer Cooperative of the Zou Intellectual Property Bureau of the People's Republic of China V. Description of the Invention (4) In summary, although the present invention has been The embodiments are disclosed as above, but it is not intended to limit the present invention. Any person skilled in the art can make various modifications and retouches without departing from the spirit and scope of the present invention. The scope of the patent application shall prevail. (Please read the notes on the back before filling this page)

This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)

Claims (1)

520447 3862twadf2.doc / 008 A8B8C8D8 ^ /-Λ f Printed as Patent No. 90 1 12339 by the Consumers' Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs Amendment Date of this amendment: 丨 | 1 place · 10 · 15 --~ ~~ 1 · An interference filter suitable for a narrow band-pass filter in a high-density multi-wave divider. The interference filter includes at least: a substrate; a plurality of reflector layers, and the reflector layers Is arranged on the substrate, and each of the plurality of mirror layers is composed of a plurality of first dielectric layers and a plurality of second dielectric layers, wherein the material of the first dielectric layers is a titanium oxide A thin film mixed with a silicon oxide; and a plurality of space layers, each of which is disposed between two mirror layers to form a cavity. 2. The interference filter according to item 1 of the scope of the patent application, wherein the refractive index of the second dielectric layers is smaller than the refractive index of the first dielectric layers. 3. The interference filter according to item 1 of the scope of patent application, wherein the thicknesses of the first dielectric layers and the second dielectric layers are a quarter-wavelength optical thickness. 4. The interference filter according to item 1 of the scope of the patent application, wherein the thickness of the space layers is an integer multiple of the optical thickness at a half wavelength. 5. The interference filter described in item 1 of the scope of patent application is plated by ion beam sputtering. 6. The interference filter according to item 1 of the scope of patent application is plated by the ion beam assisted method. 7. The dry filter according to item 1 of the scope of patent application, wherein the first dielectric layers and the second dielectric layers are alternately stacked. 17 This paper size applies to China National Standard (CNS) A4 specification (21〇X 297 issued) -------------- si (Please read the precautions on the back before filling this page) Order Line.