Preparation Method of Channel-Type Planar Waveguide Amplifier and Channel-Type Planar Waveguide Amplifier

Abstract

The present invention relates to a method for preparing a channel-type planar waveguide amplifier and a channel-type planar waveguide amplifier. The method for preparing the channel-type planar waveguide obtains an optical substrate with a developed channel structure by exposing and developing a photoresist spin-coated on the optical substrate using a photolithography mask plate with a preset channel structure, and then uses a plasma generated by an etching gas to etch a plurality of channels on the optical substrate according to the developed channel structure. Finally, a selected rare-earth-doped chalcogenide material is condensed on the optical substrate with etched channels by a melting-quenching method to form a chalcogenide thin film on the surface of the optical substrate; moreover, the selected rare-earth-doped chalcogenide material is condensed in the channels of the optical substrate by a melting-quenching method, which avoids etching the doped rare-earth material and ensures that the doped rare-earth material does not lose its activity during the condensation process, thereby obtaining the high-quality planar waveguide amplifier to be prepared.

Description

Technical Field

[0001] The present invention relates to the field of optical amplifiers, and particularly to a preparation method of a channel-type planar waveguide amplifier and a channel-type planar waveguide amplifier. Background Art

[0002] Optical fiber amplifiers are one of the indispensable core components in optical fiber communication networks, which can amplify optical signals transmitted in optical fibers. The currently widely used erbium-doped silica fiber amplifier (Erbium Doped Fiber Amplifier, abbreviated as EDFA) usually has an amplification effect on optical signals reaching more than 30 dB at a wavelength of 1.5 μm. Through one-time amplification processing, optical signals can be transmitted over 100 kilometers. However, such optical fiber amplifiers are generally large in size and expensive, which is not conducive to the application requirements of small networks or other special occasions.

[0003] With the development of waveguide technology, planar waveguides (or optical planar waveguides, planar optical waveguides) have gradually become a new trend in optical signal transmission, and a planar waveguide amplifier scheme based on planar waveguides has also been proposed. The so-called planar optical waveguide means that the optical waveguide is located in a plane. Planar waveguides have many advantages. For example, the processing technology of the entire waveguide can be compatible with standard semiconductor processing technology, and the planar waveguide based on the chip usually only has a small area of centimeter level, with low power consumption, which is convenient for large-scale production and integration on the chips of large-scale optical devices.

[0004] Chinese Patent Application CN104345385A discloses a silicon-based polymer planar optical waveguide amplifier doped with rare earth neodymium complexes and a preparation method of the silicon-based polymer planar optical waveguide amplifier. The silicon-based polymer planar optical waveguide amplifier includes a silicon substrate, a lower cladding layer, and a waveguide core layer. The lower cladding layer is disposed on the upper surface of the silicon substrate, and the waveguide core layer is disposed on the upper surface of the lower cladding layer. The waveguide core layer uses a polymer material doped with rare earth neodymium complexes. The preparation method of the silicon-based polymer planar optical waveguide amplifier includes: Step S1, preparing a polymer solution doped with rare earth neodymium complexes; Step S2, growing a layer of SiO2 on the silicon substrate by thermal oxidation to form the lower cladding layer; Step S3, spin-coating the polymer solution doped with rare earth neodymium complexes on the lower cladding layer and curing to form the core layer; Step S4, depositing an aluminum film on the core layer by magnetron sputtering; Step S5, spin-coating a layer of ultraviolet negative photoresist on the aluminum film, then performing pre-baking, ultraviolet exposure, post-baking, and developing to transfer the pattern on the photomask to the ultraviolet negative photoresist and the aluminum film to form an aluminum mask corresponding to the pattern of the waveguide core layer; Step S6, using oxygen reactive ion etching to pattern the core layer to form the waveguide core layer, and at the same time removing the ultraviolet negative photoresist in the exposed part; Step S7, removing the aluminum mask with a developer.

[0005] However, there are also some problems with the method for preparing a planar optical waveguide amplifier disclosed in the above-mentioned invention patent application CN104345385A: Since the cured core layer is formed of a polymer material doped with a rare earth neodymium complex, when the core layer is etched by the oxygen reactive ion etching method, the oxygen reactive ions will directly interact with the rare earth material (i.e., neodymium). However, since the rare earth material is difficult to be etched by the oxygen reactive ions, this will result in a relatively large roughness on the structural surface and sidewalls of the planar waveguide obtained after etching, which will bring a relatively large optical transmission loss to the planar waveguide, and further have a serious adverse impact on the amplification gain of the waveguide device (such as a planar optical waveguide amplifier) made using the planar waveguide.

[0006] In addition, U.S. Patent No. US8144392B2 discloses a waveguide amplifier with an erbium-doped gallium lanthanum sulfide glass sputtering film. First, a 6-nanometer-thick Cr is coated on a fused silica glass substrate as an adhesion promoter, then a 3.7-micron-thick polyimide stripping layer is spin-coated, and then a 1.1-micron-thick positive photoresist is spin-coated; then, the above structure is exposed and developed through an optical mask plate. After development, an undercut channel structure will appear in the stripping layer; finally, a film of erbium-ion-doped GLS is deposited by magnetron sputtering, so as to form a ridge waveguide structure in the channel structure formed in the previous step, and finally achieve internal gain (i.e., amplification effect), and the gain effect can reach 6.7 dB. However, there are also some problems with the waveguide amplifier prepared according to the above-mentioned U.S. Patent No. US8144392B2:

[0007] First of all, although the rare earth-doped chalcogenide glass material exhibits good reproducible rare earth fluorescence properties. However, since this invention patent US8144392B2 uses thermal evaporation and magnetron sputtering methods to deposit a film of erbium-ion-doped GLS on the channel structure, the doped rare earth material undergoes a process of decomposing into atomic or ionic states and then re-precipitating on the fused silica glass substrate, which will lead to a decrease or even complete loss of the activity of the rare earth ions doped in the GLS film, and it is impossible to continue to exhibit good fluorescence properties, seriously affecting the final amplification performance of the waveguide amplifier;

[0008] Secondly, chalcogenide materials, especially compounds with more than three elements, often show phase separation during the film deposition process, resulting in the components of the film being different from the corresponding bulk materials, causing the performance to show uncertainty; at the same time, the film material exhibits stronger structural relaxation, which will cause a large change in the performance of the optical device based on the film preparation over time.

[0009] Therefore, how to avoid large roughness on the surface and sidewalls of the structure of the planar waveguide amplifier obtained after plasma etching and maintain the activity and fluorescence performance of rare earth ions in the prepared thin film has become the key to fabricating high-quality planar waveguide amplifiers. Summary of the Invention

[0010] The first technical problem to be solved by the present invention is to provide a method for fabricating a channel-type planar waveguide amplifier for the above-mentioned prior art.

[0011] The second technical problem to be solved by the present invention is to provide a channel-type planar waveguide amplifier for the above-mentioned prior art.

[0012] The technical solution adopted by the present invention to solve the first technical problem is as follows: A method for fabricating a channel-type planar waveguide amplifier, characterized by comprising the following steps S1 to S3:

[0013] Step S1, etching a plurality of channels according to the channel structure developed on the optical substrate by using the plasma generated by the etching gas;

[0014] Step S2, condensing the selected rare earth-doped chalcogenide material on the optical substrate etched with channels by using the melt-quenching method to form a chalcogenide thin film on the surface of the optical substrate;

[0015] Step S3, condensing the selected rare earth-doped chalcogenide material in the channels of the optical substrate by using the melt-quenching method to obtain the planar waveguide amplifier to be fabricated.

[0016] Improved, in the method for fabricating a channel-type planar waveguide amplifier, before step S1, it further includes:

[0017] Step a1, spin-coating a photoresist on the optical substrate;

[0018] Step a2, exposing and developing the photoresist by using a photolithography mask with a preset channel structure to obtain an optical substrate developed with a channel structure; wherein, the preset channel structure contains a plurality of channels.

[0019] Further, in the method for fabricating a channel-type planar waveguide amplifier, after step S3, it further includes: performing a film removal treatment on the condensed chalcogenide thin film located outside the channel and protruding from the surface of the optical substrate.

[0020] Still further, in the method for fabricating a channel-type planar waveguide amplifier, perform a film removal treatment according to the thickness of the chalcogenide thin film located outside the channel protruding from the surface of the optical substrate:

[0021] When the thickness of the chalcogenide thin film protruding from the surface of the optical substrate is greater than a preset thickness threshold, remove the chalcogenide thin film; otherwise, do not remove the chalcogenide thin film.

[0022] Further improved, in the method for preparing the channel-type planar waveguide amplifier, between step a1 and step a2, it further includes: washing off the photoresist remaining on the optical substrate.

[0023] Further improved, in the method for preparing the channel-type planar waveguide amplifier, the channel structure is designed on the photomask according to the following steps b1 to b3:

[0024] Step b1, determining the refractive index of the rare-earth doped material required for the planar waveguide amplifier to be prepared and the refractive index of the required optical substrate;

[0025] Step b2, according to the determined refractive index of the rare-earth doped material and the refractive index of the optical substrate, simulating the light field distribution at a preset wavelength value;

[0026] Step b3, according to the simulated light field distribution, fabricating a channel structure on the photomask that matches the light field distribution.

[0027] Improved, in the method for preparing the channel-type planar waveguide amplifier, in step S3, it further includes: a step of performing measures to reduce the crystallization rate during the condensation process of the rare-earth doped chalcogenide material.

[0028] Optionally, in the method for preparing the channel-type planar waveguide amplifier, the rare earth is Er or Pr or Ho or Dy or Tm.

[0029] Optionally, in the method for preparing the channel-type planar waveguide amplifier, the chalcogenide material is Ge-Ga-S or Ge-Ga-Se.

[0030] The technical solution adopted by the present invention to solve the second technical problem is: a channel-type planar waveguide amplifier, including an optical substrate, characterized in that a plurality of channels are etched on the optical substrate, and the surface of the optical substrate has a chalcogenide thin film formed by condensing a rare-earth doped chalcogenide material using the melt-quenching method, and each channel is completely filled with a rare-earth doped chalcogenide material condensed using the melt-quenching method.

[0031] Preferably, in the channel-type planar waveguide amplifier, the thickness of the rare-earth doped chalcogenide material filled in the channel is less than the depth of the channel.

[0032] Optionally, in the channel-type planar waveguide amplifier, the optical substrate is a quartz substrate.

[0033] Compared with the prior art, the advantages of the present invention are:

[0034] First, in the method for preparing a channel-type planar waveguide amplifier of the present invention, the plasma generated by the etching gas directly performs an etching process on the optical substrate in advance to obtain a channel, and then a rare-earth doped chalcogenide material is condensed on the surface of the optical substrate and in the channel to form a rare-earth doped chalcogenide thin film, avoiding the plasma directly etching the rare-earth ions, thereby avoiding large roughness on the surface and sidewalls of the prepared channel-type planar waveguide amplifier structure. This can ensure the flatness of the surface and sidewalls of the channel-type planar waveguide amplifier structure, reduce the optical transmission loss, and further improve the amplification gain performance of the channel-type planar waveguide amplifier.

[0035] Secondly, considering the activity and fluorescence properties of rare-earth ions, the present invention uses the melt-quenching method to condense the selected rare-earth doped chalcogenide material on the etched optical substrate with channels and in the channels of the optical substrate, avoiding the loss of activity and rare-earth fluorescence properties of the doped rare-earth material due to the process of decomposing into atomic or ionic states. Thereby, the optical stability of the rare-earth ions doped in the chalcogenide material is improved, and the formed rare-earth doped chalcogenide thin film also exhibits good optical stability, further improving the amplification performance of the channel-type planar waveguide amplifier. Brief Description of the Drawings

[0036] Figure 1 SEM image of a ridge-type planar waveguide object obtained by a conventional preparation method of directly performing plasma etching treatment on a rare-earth doped Er chalcogenide thin film;

[0037] Figure 2 Schematic flow chart of the method for preparing a channel-type planar waveguide amplifier in the present invention;

[0038] Figure 3 Schematic diagram of the optical field distribution simulated in the first embodiment of the present invention;

[0039] Figure 4 Schematic diagram of the original structure of the optical substrate in the present invention;

[0040] Figure 5 For Figure 4 Schematic diagram when the optical substrate shown has channels etched;

[0041] Figure 6 For Figure 5 Schematic diagram when the channels of the optical substrate shown are completely filled with a rare-earth doped chalcogenide material;

[0042] Figure 7 For Figure 6 Schematic diagram after the excess rare-earth doped chalcogenide material located outside the channel shown is removed;

[0043] Figure 8SEM image of the physical product when the channel of the optical substrate is not filled with rare-earth-doped chalcogenide material;

[0044] Figure 9 is Figure 8 SEM image of the physical product when the channel of the optical substrate shown is filled with rare-earth-doped chalcogenide material;

[0045] Figure 10 Schematic diagram of the amplification gain performance test system of the channel-type planar waveguide amplifier in the present invention;

[0046] Figure 11 Schematic diagram of the measurement result of the amplification performance of the Ge-Ga-S channel-type planar waveguide amplifier doped with rare-earth Er;

[0047] Figure 12 Schematic diagram of the measurement result of the amplification performance of the Ge-Ga-Se channel-type planar waveguide amplifier doped with rare-earth Er. Detailed implementation manners

[0048] The present invention will be further described in detail below in conjunction with the embodiments with reference to the drawings.

[0049] Embodiment 1

[0050] This embodiment provides a preparation method for a chalcogenide glass channel-type planar waveguide amplifier doped with rare-earth Er. The chalcogenide material corresponding to the chalcogenide glass is Ge-Ga-S. Refer to Figure 2 As shown, the preparation method for the chalcogenide glass channel-type planar waveguide amplifier doped with rare-earth Er includes the following steps 1 to 4:

[0051] Step 1, design a channel structure on a selected optical substrate 11 in advance; wherein, the selected optical substrate is a quartz substrate, and the channel structure on the optical substrate 11 is obtained by processing in the following manner of steps a1 to a2:

[0052] Step a1, spin-coat a photoresist on the optical substrate 11;

[0053] Step a2, expose and develop the above-mentioned photoresist by using a photomask with a preset channel structure to obtain an optical substrate with a developed channel structure; wherein, the preset channel structure contains a plurality of channels, and the channel structure is designed on the photomask in the following manner of steps a21 to a23 in this embodiment:

[0054] Step a21, determine the refractive index of the rare-earth Er-doped material required for the planar waveguide amplifier to be prepared and the refractive index of the required optical substrate 11; the refractive index of the rare-earth Er-doped material here is n1, and the refractive index of the quartz substrate is n2;

[0055] Step a22: According to the determined refractive index n1 of the rare-earth Er-doped material and the refractive index n2 of the optical substrate 11, simulate the optical field distribution at a wavelength of 1.5 μm.

[0056] Step a23: According to the simulated optical field distribution, fabricate a channel structure matching the optical field distribution on the photomask. Among them, using the refractive index n1 of the rare-earth Er-doped material and the refractive index n2 of the quartz substrate to simulate the optical field distribution at a wavelength of 1.5 μm belongs to the conventional technical means that are easily known to those skilled in the art, and the specific simulation process of the optical field distribution will not be elaborated here; see the optical field distribution situation simulated here in Figure 3 as shown;

[0057] Step 2: Use the plasma generated by the etching gas to etch multiple channels according to the developed channel structure on the optical substrate. Among them, the etching gas used here is a mixed gas of CHF3 gas and Ar gas, and the pressure value range of the etching chamber corresponding to the mixed gas of CHF3 gas and Ar gas is 1-10 Pa, and the RF power of the etching target is 50-200 W; see the structural situations of the quartz substrate 11 before and after etching the channels in Figure 4 and Figure 5 as shown; at this time, the photoresist remaining on the optical substrate 11 can also be washed off as needed;

[0058] Step 3: Condense the selected rare-earth Er-doped chalcogenide material Ge-Ga-S on the optical substrate 11 etched with channels 110 by the melt-quenching method to form a chalcogenide Ge-Ga-S thin film on the surface of the optical substrate 11.

[0059] Step 4: Condense the selected above-mentioned rare-earth Er-doped chalcogenide material Ge-Ga-S into the channels 110 of the optical substrate 11 to obtain the planar waveguide amplifier to be prepared.

[0060] In order to improve the smoothness of the surface of the prepared planar waveguide amplifier, after step 4 of the preparation method of the channel-type planar waveguide amplifier in this embodiment is completed, the condensed chalcogenide thin film located outside the channels 110 and protruding from the surface of the optical substrate 11 will also be polished to ensure the smoothness of the surface of the planar waveguide amplifier. Specifically, the treatment can be carried out according to the thickness of the chalcogenide Ge-Ga-S thin film located outside the channels 110 protruding from the surface of the optical substrate 11: when the thickness of the chalcogenide Ge-Ga-S thin film protruding from the surface of the optical substrate 11 is greater than the preset thickness threshold, the chalcogenide Ge-Ga-S thin film is polished off; otherwise, the chalcogenide Ge-Ga-S thin film is not polished off.

[0061] In order to reduce the crystallization rate of the rare-earth-doped Er chalcogenide material Ge-Ga-S during the condensation process, the method for preparing a chalcogenide glass channel-type planar waveguide amplifier according to this embodiment also adopts ice water, liquid nitrogen, or adds trace transition metal elements such as nickel during the condensation process of the rare-earth-doped Er chalcogenide material Ge-Ga-S to reduce the crystallization rate.

[0062] This embodiment also provides a channel-type planar waveguide amplifier prepared by using the method for preparing a rare-earth-doped Er chalcogenide glass channel-type planar waveguide amplifier as described above. Refer to Figure 6 As shown, that is, a schematic diagram when the channel of the optical substrate is completely filled with the rare-earth-doped chalcogenide material by condensation. At this time, the corresponding product is a channel-type planar waveguide amplifier. The channel-type planar waveguide amplifier 1 includes an optical substrate 11, and a plurality of channels 110 are etched on the optical substrate 11 by using the plasma generated by the etching gas. The surface of the optical substrate 11 has a Ge-Ga-S chalcogenide thin film formed by condensing the rare-earth-doped Er chalcogenide material Ge-Ga-S by the melt-quenching method, and each channel 110 is completely filled with the rare-earth-doped Er chalcogenide material Ge-Ga-S condensed by the melt-quenching method.

[0063] In order to make the structure surface and sidewalls of the rare-earth-doped Er chalcogenide glass channel-type planar waveguide amplifier not have obvious roughness and be very flat as a whole, in the chalcogenide glass channel-type planar waveguide amplifier of this embodiment, refer to Figure 7 As shown, the thickness of the rare-earth-doped Er chalcogenide material Ge-Ga-S filled in the channel 110 is less than the depth of the channel 110. In this way, it can be ensured that there is no excess rare-earth-doped Er chalcogenide material Ge-Ga-S outside the channel 110. In this way, on the outside of each channel 110, there will be no Ge-Ga-S chalcogenide thin film doped with rare-earth Er protruding from the optical substrate 11, and the surface of the obtained chalcogenide glass channel-type planar waveguide amplifier is flatter. Among them, Figure 1 shows a scanning electron microscope image of a ridge-type planar waveguide obtained by the traditional preparation method of directly performing plasma etching treatment on a rare-earth-doped Er chalcogenide thin film. It can be seen that the structure surface and sidewalls of this planar waveguide amplifier have obvious roughness. Figure 9 shows a scanning electron microscope (SEM) image of the product when the channel of the optical substrate is filled with the rare-earth-doped chalcogenide material. It can be seen that the structure surface and sidewalls of the rare-earth-doped Er channel-type planar waveguide amplifier product have no obvious roughness and are very flat as a whole.

[0064] This embodiment is for the prepared rare-earth-doped Er chalcogenide glass channel-type planar waveguide amplifier (refer to Figure 7Measurements were made on the optical amplification performance (or gain performance) of the planar waveguide amplifier product in the state shown. See Figure 10 As shown, in the amplification gain performance test system of the chalcogenide glass channel-type planar waveguide amplifier, the pump light emitted by the pump light source 31 and the signal light emitted by the signal light source 32 enter the prepared channel-type planar waveguide amplifier 1 through the coupling device 33 and are coupled into it through a lens fiber 34. After the signal light is amplified by the channel-type planar waveguide amplifier 1, it is coupled into the spectrometer 36 through another lens fiber 35 on the other side of the channel-type planar waveguide amplifier 1, so as to realize the measurement of the amplified signal light. Among them, an attenuator 37 is provided between the signal light source 32 and the coupling device 33. The above-mentioned lens fiber 34 and lens fiber 35 are fixed on the three-dimensional micro-displacement platform 30 to adjust the relative positions of each lens fiber and the channel-type planar waveguide amplifier 1 to improve the coupling efficiency. Of course, if a free-space optical path is used, appropriate lenses can be used to replace the lens fibers to couple light into / out of the channel-type planar waveguide. Figure 11 The measurement results of the amplification performance of the Ge-Ga-S channel-type planar waveguide amplifier doped with rare-earth Er in this embodiment are given. From Figure 11 it can be seen that the amplification gain of the chalcogenide glass channel-type planar waveguide amplifier doped with rare-earth Er can reach 19.5 dB at an input power of 250 mW.

[0065] In this embodiment, the photoresist spin-coated on the optical substrate is exposed and developed by using a photolithography mask plate with a preset channel structure to obtain an optical substrate with a developed channel structure. Then, a plasma generated by an etching gas is used to etch a plurality of channels on the optical substrate according to the developed channel structure. Finally, the selected chalcogenide material doped with rare-earth is condensed on the etched optical substrate by the melt-quenching method to form a chalcogenide thin film on the surface of the optical substrate; and, the selected chalcogenide material doped with rare-earth is condensed in the channels of the optical substrate by the melt-quenching method, so as to obtain the planar waveguide amplifier to be prepared.

[0066] Compared with the traditional method for preparing a planar waveguide amplifier, which requires etching a rare-earth-doped thin film on an optical substrate to obtain a channel, in this embodiment, the plasma generated by the etching gas directly etches the optical substrate in advance to obtain a channel, and then a rare-earth-doped chalcogenide material is condensed on the surface of the optical substrate and in the channel to form a rare-earth-doped chalcogenide thin film, avoiding direct etching of rare-earth ions by the plasma, thereby avoiding large roughness on the surface and sidewalls of the prepared channel-type planar waveguide amplifier structure caused by the inability of the doped rare-earth ions to be etched by plasma. This can ensure the flatness of the surface and sidewalls of the channel-type planar waveguide amplifier structure, reduce optical transmission loss, and thus improve the amplification gain performance of the channel-type planar waveguide amplifier.

[0067] In addition, in this embodiment, the selected rare-earth-doped chalcogenide material is condensed on the etched optical substrate and in the channel of the optical substrate by the melt-quenching method, avoiding the loss of activity and the degradation of rare-earth fluorescence performance of the rare-earth-doped material during the thin film fabrication process due to the process of decomposing into atomic or ionic states. Thereby, the optical stability of the rare-earth ions doped in the chalcogenide material is improved, and the formed rare-earth-doped chalcogenide thin film also exhibits good optical stability, further improving the amplification performance of the channel-type planar waveguide amplifier.

[0068] This embodiment provides an optical device, which applies the above-mentioned channel-type planar waveguide amplifier made of rare-earth-doped Er chalcogenide glass. Of course, according to actual needs, the above-mentioned channel-type planar waveguide amplifier made of rare-earth-doped Er chalcogenide glass can also be applied to optical devices such as a splitter, a star coupler, a variable optical attenuator (VOA), an optical switch, an interleaver, and an array waveguide grating (AWG).

[0069] This embodiment provides a device. Specifically, this device applies any one of the above-mentioned optical devices.

[0070] Embodiment 2

[0071] This embodiment provides a method for preparing a channel-type planar waveguide amplifier made of rare-earth-doped Er chalcogenide glass, and the chalcogenide material corresponding to the chalcogenide glass is Ge-Ga-Se. Refer to Figure 2 As shown, the method for preparing a channel-type planar waveguide amplifier made of rare-earth-doped Er chalcogenide glass includes the following steps 1 to 4:

[0072] Step 1: Design a channel structure on the selected optical substrate 11 in advance; among them, the selected optical substrate is a quartz substrate, and the channel structure on the optical substrate 11 is obtained by pre-processing according to the following steps a1 to a2:

[0073] Step a1: Spin-coat photoresist on the optical substrate 11;

[0074] Step a2: Expose and develop the above-mentioned photoresist using a photomask with a preset channel structure to obtain an optical substrate with a developed channel structure; among them, the preset channel structure contains multiple channels, and in this embodiment, the channel structure is designed on the photomask according to the following steps a21 to a23:

[0075] Step a21: Determine the refractive index of the rare earth Er-doped material required for the planar waveguide amplifier to be prepared and the refractive index of the required optical substrate 11; here, the refractive index of the rare earth Er-doped material is n1, and the refractive index of the quartz substrate is n2.

[0076] Step a22: According to the determined refractive index n1 of the rare earth Er-doped material and the refractive index n2 of the optical substrate 11, simulate the light field distribution at a wavelength of 1.5 μm.

[0077] Step a23: According to the simulated light field distribution, fabricate a channel structure on the photomask that matches the light field distribution. Among them, using the refractive index n1 of the rare earth Er-doped material and the refractive index n2 of the quartz substrate to simulate the light field distribution at a wavelength of 1.5 μm belongs to the conventional technical means that are easily known to those skilled in the art, and the specific simulation process for the light field distribution will not be elaborated here.

[0078] Step 2: Use the plasma generated by the etching gas to etch multiple channels according to the developed channel structure on the optical substrate; among them, the etching gas used here is a mixed gas of CHF3 gas and Ar gas, the pressure value range of the etching chamber corresponding to the mixed gas of CHF3 gas and Ar gas is 1 to 10 Pa, and the RF power of the etching target is 50 to 200 W; for the structural conditions of the quartz substrate 11 before and after etching the channels, please refer to Figure 4 and Figure 5 shown; at this time, the photoresist remaining on the optical substrate 11 can also be washed off as needed.

[0079] Step 3: Condense the selected rare earth Er-doped chalcogenide material Ge-Ga-Se on the optical substrate 11 etched with channels 110 by the melt-quenching method to form a chalcogenide Ge-Ga-Se thin film on the surface of the optical substrate 11.

[0080] Step 4: Condense the selected chalcogenide material Ge-Ga-Se doped with rare earth Er in the channel 110 of the optical substrate 11 by the melting-quenching method to obtain the planar waveguide amplifier to be prepared.

[0081] To improve the smoothness of the surface of the prepared planar waveguide amplifier, after step 4 is completed in the preparation method of the channel-type planar waveguide amplifier of this embodiment, the condensed chalcogenide thin film located outside the channel 110 and protruding from the surface of the optical substrate 11 will be polished to ensure the smoothness of the surface of the planar waveguide amplifier. Specifically, the treatment can be carried out according to the thickness of the chalcogenide Ge-Ga-Se thin film located outside the channel 110 protruding from the surface of the optical substrate 11: when the thickness of the chalcogenide Ge-Ga-Se thin film protruding from the surface of the optical substrate 11 is greater than the preset thickness threshold, the chalcogenide Ge-Ga-Se thin film is polished away; otherwise, the chalcogenide Ge-Ga-Se thin film is not polished away.

[0082] To reduce the crystallization rate of the chalcogenide material Ge-Ga-Se doped with rare earth Er during the condensation process, the preparation method of the chalcogenide glass channel-type planar waveguide amplifier of this embodiment will also use ice water, liquid nitrogen or add trace transition metal elements such as nickel during the condensation process of the chalcogenide material Ge-Ga-Se doped with rare earth Er to reduce the crystallization rate.

[0083] This embodiment also provides a channel-type planar waveguide amplifier prepared by using the above preparation method of the chalcogenide glass channel-type planar waveguide amplifier doped with rare earth Er. See Figure 6 As shown, that is, the schematic diagram when the channel of the optical substrate is completely filled with the rare earth-doped chalcogenide material. At this time, the corresponding product is a channel-type planar waveguide amplifier. The channel-type planar waveguide amplifier 1 includes an optical substrate 11, and several channels 110 are etched on the optical substrate 11 by the plasma generated by the etching gas. The surface of the optical substrate 11 has a Ge-Ga-Se chalcogenide thin film formed by condensing the chalcogenide material Ge-Ga-Se doped with rare earth Er by the melting-quenching method, and each channel 110 is completely filled with the chalcogenide material Ge-Ga-Se doped with rare earth Er condensed by the melting-quenching method.

[0084] To make the structural surface and side walls of the chalcogenide glass channel-type planar waveguide amplifier doped with rare earth Er not significantly rough and very flat as a whole, in the chalcogenide glass channel-type planar waveguide amplifier of this embodiment, see Figure 7As shown, the thickness of the rare-earth-doped Er chalcogenide material Ge-Ga-Se filled in the channel 110 is less than the depth of the channel 110. In this way, it can be ensured that there is no excess rare-earth-doped Er chalcogenide material Ge-Ga-Se outside the channel 110. Thus, on the outside of each channel 110, there will be no Ge-Ga-Se chalcogenide thin film doped with rare-earth Er protruding from the optical substrate 11, and the surface of the obtained chalcogenide glass channel-type planar waveguide amplifier is smoother.

[0085] This embodiment measures the optical amplification performance (or gain performance) of the prepared rare-earth-doped Er chalcogenide glass channel-type planar waveguide amplifier (see the planar waveguide amplifier product in the state shown in Figure 7 ). See Figure 10 As shown, in the amplification gain performance test system of the chalcogenide glass channel-type planar waveguide amplifier, the pump light emitted by the pump light source 31 and the signal light emitted by the signal light source 32 are coupled into the prepared channel-type planar waveguide amplifier 1 through a lens fiber 34 via a coupling device 33. After the signal light is amplified by the channel-type planar waveguide amplifier 1, it is coupled into a spectrometer 36 through another lens fiber 35 on the other side of the channel-type planar waveguide amplifier 1, so as to realize the measurement of the amplified signal light. Among them, an attenuator 37 is arranged between the signal light source 32 and the coupling device 33. The above-mentioned lens fiber 34 and lens fiber 35 are fixed on a three-dimensional micro-displacement platform 30 to adjust the relative positions of each lens fiber and the channel-type planar waveguide amplifier 1 to improve the coupling efficiency. Of course, if a free-space optical path is used, appropriate lenses can be used to replace the lens fibers to couple light into / out of the channel-type planar waveguide. Figure 12 The measurement results of the amplification performance of the rare-earth-doped Er Ge-Ga-Se channel-type planar waveguide amplifier are given. It can be seen from Figure 12 that the amplification gain of the rare-earth-doped Er chalcogenide glass channel-type planar waveguide amplifier can reach 25 dB under an input power of 250 mW.

[0086] In this embodiment, by using a photolithography mask plate with a preset channel structure to expose and develop the photoresist spin-coated on the optical substrate, an optical substrate with a developed channel structure is obtained. Then, a plasma generated by an etching gas is used to etch multiple channels on the optical substrate according to the developed channel structure. Finally, the selected rare-earth-doped chalcogenide material is condensed on the etched optical substrate by the melt-quenching method to form a chalcogenide thin film on the surface of the optical substrate; and the selected rare-earth-doped chalcogenide material is condensed in the channels of the optical substrate by the melt-quenching method, thereby obtaining the planar waveguide amplifier to be prepared.

[0087] Compared with the traditional method for preparing a planar waveguide amplifier, which requires etching a rare-earth-doped thin film on an optical substrate to obtain a channel, in this embodiment, the plasma generated by the etching gas directly etches the optical substrate in advance to obtain a channel, and then a rare-earth-doped chalcogenide material is condensed on the surface of the optical substrate and in the channel to form a rare-earth-doped chalcogenide thin film, avoiding direct etching of the rare-earth ions by the plasma, thereby avoiding large roughness on the surface and sidewalls of the prepared channel-type planar waveguide amplifier structure caused by the inability of the doped rare-earth ions to be etched by the plasma. This can ensure the flatness of the surface and sidewalls of the channel-type planar waveguide amplifier structure, reduce the optical transmission loss, and further improve the amplification gain performance of the channel-type planar waveguide amplifier.

[0088] In addition, in this embodiment, the selected rare-earth-doped chalcogenide material is condensed on the etched optical substrate and in the channel of the optical substrate by the melt-quenching method, avoiding the loss of activity and rare-earth fluorescence performance of the doped rare-earth material during the thin film preparation process due to the process of decomposing into atomic or ionic states. This improves the optical stability of the rare-earth ions doped in the chalcogenide material, making the formed rare-earth-doped chalcogenide thin film also exhibit good optical stability, and further improving the amplification performance of the channel-type planar waveguide amplifier.

[0089] This embodiment provides an optical device that applies the above-mentioned rare-earth-Er-doped chalcogenide glass channel-type planar waveguide amplifier. Of course, according to actual needs, the above-mentioned rare-earth-Er-doped chalcogenide glass channel-type planar waveguide amplifier can also be applied to optical devices such as splitters, star couplers, variable optical attenuators (VOAs), optical switches, interleaves, and array waveguide gratings (AWGs).

[0090] This embodiment provides a device. Specifically, this device applies any of the above-mentioned optical devices.

[0091] It should be noted that during the actual preparation process of the planar waveguide amplifier, rare-earth materials such as Er, Pr, Ho, Dy, or Tm and other chalcogenide materials can be selected according to actual needs to prepare different planar waveguide amplifiers.

[0092] Although the preferred embodiments of the present invention have been described in detail above, it should be clearly understood that various changes and modifications can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for fabricating a channel-type planar waveguide amplifier, characterized in that, It includes the following steps S1 to S3: Step S1, etching a plurality of channels in accordance with the developed channel structure on the optical substrate by using the plasma generated by the etching gas; Step S2, condensing the selected rare-earth doped chalcogenide material on the optical substrate etched with channels by using the melt-quenching method to form a chalcogenide thin film on the surface of the optical substrate; Step S3, condensing the selected rare-earth doped chalcogenide material in the channels of the optical substrate by using the melt-quenching method to obtain the planar waveguide amplifier to be prepared; Moreover, after step S3, it further includes: performing a film polishing treatment on the condensed chalcogenide thin film located outside the channels and protruding from the surface of the optical substrate.

2. The manufacturing method of the channel-type planar waveguide amplifier according to claim 1, wherein, Before step S1, it further includes: Step a1, spin-coating a photoresist on the optical substrate; Step a2, exposing and developing the photoresist by using a photomask with a preset channel structure to obtain an optical substrate with a developed channel structure; wherein, the preset channel structure contains a plurality of channels.

3. The manufacturing method of the channel-type planar waveguide amplifier according to claim 1, characterized in that Performing a film polishing treatment according to the thickness of the chalcogenide thin film protruding from the surface of the optical substrate outside the channels: When the thickness of the chalcogenide thin film protruding from the surface of the optical substrate is greater than a preset thickness threshold, polishing off the chalcogenide thin film; otherwise, not polishing off the chalcogenide thin film.

4. The method for fabricating a channel-type planar waveguide amplifier according to claim 1, characterized in that, Between step a1 and step a2, it further includes: washing off the photoresist remaining on the optical substrate.

5. The method for preparing a channel-type planar waveguide amplifier according to claim 1, wherein Designing the channel structure on the photomask in the following manner of step b1 to step b3: Step b1, determining the refractive index of the rare-earth doped material required for the planar waveguide amplifier to be prepared and the refractive index of the required optical substrate; Step b2, simulating the light field distribution at a preset wavelength value according to the determined refractive index of the rare-earth doped material and the refractive index of the optical substrate; Step b3, fabricating a channel structure matching the light field distribution on the photomask according to the simulated light field distribution.

6. The method for preparing a channel-type planar waveguide amplifier according to any one of claims 1 to 5, characterized in that In step S3, it further includes: performing a step of taking measures to reduce the crystallization rate during the condensation process of the rare-earth doped chalcogenide material.

7. The method for preparing a channel-type planar waveguide amplifier according to any one of claims 1 to 5, characterized in that, The rare earth is Er or Pr or Ho or Dy or Tm, and the chalcogenide material is Ge-Ga-S or Ge-Ga-Se.

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