Multi-parameter tunable filter based on phase-change Bragg grating and its control method

Abstract

The present invention relates to a multi-parameter tunable filter based on a phase-change Bragg grating and a control method thereof. The filter comprises a substrate, a waveguide, a phase-change Bragg grating and a grating cover layer. The waveguide is arranged on the substrate, the phase-change Bragg grating is arranged on the waveguide, and the grating cover layer is arranged on the phase-change Bragg grating, wherein the phase-change Bragg grating adopts a phase-change material GSST. The phase-change Bragg grating of the present invention adopts the phase-change material GSST, utilizes the optical properties of the phase-change material GSST, has two optical pass characteristics of a passband and a stopband without changing the device structure, and can change the refractive index distribution of the phase-change Bragg grating by adjusting various parameters of the filter, thereby realizing the adjustment of the number of filter channels and the tunability of the transmittance bandwidth, so that it can be widely used in the field of optical communications.

Description

Technical Field

[0001] The present invention relates to the field of optical communication and integrated optical technology, and in particular to a multi-parameter tunable filter based on a phase-change Bragg grating and a control method thereof. Background Art

[0002] Optical phase change materials have attracted great attention in the field of integrated optics in recent years. When a phase change occurs, the refractive index and extinction coefficient of the material are very different, and light in such dielectric materials exhibits very different propagation characteristics. In the past decade, it has been widely studied in optical imaging, on-chip integrated optical devices and radiation optical switches. Especially in the field of silicon on insulators. In 2013, M. Rudé et al. used the sulfur-based phase change material Ge2Sb2Te5 (GST) to realize a racetrack resonator-based optical switch at 1.55μm. Due to the large refractive index contrast of GST in the communication C band, the extinction ratio of the optical switch is as high as 12dB. In addition, the switch response speed is in the nanosecond level and has non-volatile characteristics (see literature: M. Rudé, et al., Optical switching at 1.55μm in silicon racetrack resonators using phase change materials, 103 (2013) 141119.). Recently, GST has also been further improved. In 2019, Y. Zhang et al. replaced part of Te with Se to obtain a phase change material with better performance. Compared with GST, a wider transparent band of 1-18.5μm was achieved (see reference: Y. Zhang, et al., Broadband transparent optical phase change materials for high-performance nonvolatile photonics, Nat Commun, 10 (2019) 4279.). In the same year, F. De Leonardis et al. used the new chalcogenide phase change material Ge2Sb2Se4Te1 (GSST) to simulate, model and analyze the non-volatile on-chip compact electro-optical optical switch, and obtained a large bandwidth of 58-72nm and an insertion loss as low as 0.3dB (see literature: F. De Leonardis, et al., Broadband Electro-Optical Crossbar Switches Using Low-Loss Ge2Sb2Se4Te1 Phase Change Material, Journal of Lightwave Technology, 37 (2019) 3183-3191.).

[0003] Filters have the ability to expand communication capacity and can play the role of wavelength division multiplexing in integrated optical systems. They are very important devices. Optical filters have long been studied extensively, such as multimode interference filters, grating filters, and filters based on the Mach-Zehnder principle or microring resonator principle. Traditional tunable filtering methods, such as acousto-optic tunable filtering, have fast tuning speeds but low filter isolation. Fiber Bragg grating filtering has a very small tuning range, is sensitive to temperature changes, is easily affected by the environment, and has poor long-term stability. The transmission peak of the Fabry-Perot interferometer is too large, which may have an adverse effect on the payload signal. In addition, its adjacent channel isolation is also very low, and it can only be used for channel monitoring. It cannot increase or decrease a signal wavelength from multiple wavelengths. In the field of integrated optics, in recent years, there have also been designs that use mode division and wavelength division multiplexing technology to improve the filter structure of the channel. However, to achieve dynamic filtering functions, it is still necessary to add additional mode converters and other photothermal modulation modules, making the structure more complex. Summary of the invention

[0004] To this end, the technical problem to be solved by the present invention is to overcome the problems existing in the prior art and provide a multi-parameter tunable filter based on a phase change Bragg grating and a control method thereof, which has two optical pass characteristics of passband and stopband without changing the device structure, and can change the refractive index distribution of the phase change Bragg grating by adjusting various parameters of the filter, thereby realizing the adjustment of the number of filter channels and the tunability of the transmittance bandwidth, so that it can be widely used in the field of optical communications.

[0005] In order to solve the above technical problems, the present invention provides a multi-parameter tunable filter based on a phase change Bragg grating, comprising a substrate, a waveguide, a phase change Bragg grating and a grating cover layer, wherein the waveguide is arranged on the substrate, the phase change Bragg grating is arranged on the waveguide, and the grating cover layer is arranged on the phase change Bragg grating, wherein the phase change Bragg grating adopts a phase change material GSST.

[0006] In one embodiment of the present invention, the width of the waveguide is 810 nm to 900 nm, and its width / thickness ratio is 2.5 to 2.8.

[0007] In one embodiment of the present invention, the duty cycle of the phase change Bragg grating is 0.15-0.19, the number of its periods is 30-100, its thickness is 80nm-170nm, its period is 332nm-355nm, and the thickness of the grating cover layer is 1-9nm.

[0008] In one embodiment of the present invention, the grating cover layer completely covers the phase change Bragg grating.

[0009] In one embodiment of the present invention, the grating cover layer only covers the top of the phase change Bragg grating.

[0010] In one embodiment of the present invention, when the incident light of the waveguide is in the quasi-TE0 mode, the effective refractive index is 2.92-2.95 when the wavelength of the light is 1550 nm.

[0011] In addition, the present invention also provides a control method for a multi-parameter tunable filter based on a phase change Bragg grating as described above, comprising: when the incident light of the waveguide is a quasi-TE0 mode, by adjusting the number of periods of the phase change Bragg grating, the phase change material GSST is in an amorphous state to achieve a stop band with a minimum light transmittance adjustable in the range of 0.03 to 0.13, and the phase change material GSST is in a crystalline state to achieve a pass band with a maximum light transmittance adjustable in the range of 0.55 to 0.7.

[0012] In one embodiment of the present invention, it includes: when the incident light of the waveguide is a quasi-TE0 mode, by adjusting the period of the phase change Bragg grating, the adjustment range is within 332nm~355nm, so that the phase change material GSST can achieve stop band and pass band in the amorphous state and crystalline state, which can be arbitrarily adjusted within the band of 1530~1565nm.

[0013] In one embodiment of the present invention, it includes: when the incident light of the waveguide is a quasi-TE0 mode, by adjusting the thickness and duty cycle of the phase change Bragg grating, the bandwidth of the stop band and the pass band of the phase change material GSST can be adjusted in the amorphous state and the crystalline state.

[0014] In one embodiment of the present invention, the method includes: when the incident light of the waveguide is in a quasi-TE0 mode, the number of channels is tunable by changing the number of the phase-change Bragg gratings and the spacing between adjacent phase-change Bragg gratings.

[0015] The above technical solution of the present invention has the following advantages compared with the prior art:

[0016] The phase change Bragg grating of the present invention adopts the phase change material GSST, and utilizes the optical properties of the phase change material GSST to have two optical pass characteristics of passband and stopband without changing the device structure. In addition, the refractive index distribution of the phase change Bragg grating can be changed by adjusting various parameters of the filter, thereby realizing the adjustment of the number of filter channels and the tunability of the transmittance bandwidth, so that it can be widely used in the field of optical communications. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0018] Figure 1 It is a schematic structural diagram of a multi-parameter tunable filter based on a phase-change Bragg grating according to the present invention.

[0019] Figure 2 It is a schematic side view of the xoz surface of the multi-parameter tunable filter structure based on the phase change Bragg grating of the present invention.

[0020] Figure 3 It is a front view schematic diagram of the xoy plane of the multi-parameter tunable filter structure based on the phase-change Bragg grating of the present invention.

[0021] Figure 4 It is a schematic structural diagram of a multi-parameter tunable filter based on a phase-change Bragg grating according to the present invention.

[0022] Figure 5 It is a complex refractive index curve diagram of the optical phase change material GSST prepared by the pulsed laser deposition method in the present invention.

[0023] Figure 6 It is the transmission spectrum of the quasi-TE0 mode in the waveguide through the tunable optical filter of the present invention under the parameter setting of Example 1.

[0024] Figure 7 This is the result of adjusting parameter P in Example 2.

[0025] Figure 8 This is the parameter dc adjustment result in Example 3.

[0026] Fig. 9 This is the result of adjusting parameter T in Example 4.

[0027] Fig.10 This is the result of adjusting parameter N in Example 5.

[0028] Fig.11 It is the light transmission spectrum result under the parameter setting of Example 6.

[0029] Fig.12 This is the parameter adjustment result in Example 6.

[0030] Fig.13 This is a schematic diagram of the structure described in Example 7.

[0031] Fig.14 It is the transmission spectrum under the parameter setting in Example 7.

[0032] Fig.15 This is a schematic diagram of the structure described in Example 8.

[0033] Fig.16 It is the transmission spectrum under the parameter setting in Example 8.

[0034] Explanation of reference numerals: 10, substrate; 20, waveguide; 30, phase-change Bragg grating; 40, grating cover layer. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0036] First, please see the attached Figure 5 As shown in the figure, a set of complex refractive indexes is shown in many experimental data of the optical phase change material Ge2Sb2Se4Te1 (GSST), which is used in both Example 1 and Example 2. When the wavelength of light is 1550nm, the refractive index difference between the amorphous state and the crystalline state of the phase change material GSST is 1.75. In the crystalline state, its refractive index is 5.13+0.42i, and in the amorphous state, its refractive index is 3.38+0.02i.

[0037] Example 1

[0038] See also Figure 1 As shown, this embodiment provides a multi-parameter tunable filter based on a phase-change Bragg grating, the filter includes a substrate 10, a waveguide 20, a phase-change Bragg grating 30 and a grating cover layer 40, the waveguide 20 is arranged on the substrate 10, the phase-change Bragg grating 30 is arranged on the waveguide 20, and the grating cover layer 40 is arranged on the phase-change Bragg grating 30, wherein the phase-change Bragg grating 30 uses a phase-change material GSST, and the incident light is input from one side of the waveguide 20 and output after passing through the phase-change Bragg grating 30. In order to make the image clear, the number of grids of the phase-change Bragg grating 30 is reduced in the figure.

[0039] The width of the waveguide 20 is 810nm to 900nm, the width / thickness ratio is 2.5 to 2.8, and the material used is single crystal silicon. A phase change Bragg grating 30 structure is deposited on the top of the waveguide 20 by pulsed laser deposition to construct a periodic refractive index distribution, thereby affecting the transmission mode in the waveguide 20.

[0040] See attached Figure 2 , the thickness T, grating period P, waveguide thickness S, and grating cover layer of the phase change Bragg grating 30 are marked. In this embodiment, the thickness of the grating cover layer 40 is 9 nm.

[0041] See attached Figure 3, the figure marks the width W of the phase change Bragg grating 30 and the waveguide 20. In addition, the material used for the substrate 10 is silicon dioxide, the material used for the waveguide 20 is silicon, the material used for the phase change Bragg grating 30 is the phase change material GSST, and the material used for the grating cover layer 40 is silicon dioxide. In this embodiment, the thickness of the substrate 10 is greater than 1 micron, and the width is greater than 3 microns; the width W of the waveguide 20 is 900nm, the thickness S is 320nm, and the length is greater than 34.5μm (the number of gratings N*period P); the width W of the phase change Bragg grating 30 is 900nm, the thickness T is 170nm, the duty cycle dc is 0.15, the number of gratings N is 100, and the grating period P is 345nm.

[0042] Figure 6 It reflects the transmission spectrum of the incident quasi-TE0 mode light through the device when the optical phase change material GSST is in the amorphous state and the crystalline state respectively under the parameter setting of Example 1. The solid line is the amorphous result, and the dotted line is the crystalline result. At this time, the center wavelength of the transmittance band stop segment in the amorphous state is 1565mn, the full width at half maximum (FWHM) is 20nm, and the insertion loss calculated in this band is -12.19dB. The center wavelength in the crystalline state is 1540nm, the FWHM is 29nm, and the corresponding insertion loss is -2.839dB. It can be seen that in the wavelength range of 1530-1565nm, when the phase change material GSST is in the crystalline state, the transmission spectrum contains a passband; when the phase change material is in the amorphous state, the transmission spectrum contains a stopband. The above two states can be obtained by adjusting the phase change material GSST without changing the device structure.

[0043] Example 2

[0044] According to the formula of Bragg resonance wavelength λ 中心波长 =2n eff P, gradually increasing P can make the transmittance red-shift (increase period) or blue-shift (decrease period). In the present invention, what is changed is the phase change Bragg grating 30 part in the overall device structure, which is equivalent to changing the folding period size of the multilayer optical film structure with high refractive index-low refractive index distribution, so the resulting Bragg-like resonance wavelength has a similar red-shift and blue-shift effect.

[0045] See attached Figure 7 , Figure 7It reflects the parameter tuning result of the multi-parameter tunable filter based on the phase-change Bragg grating under the conditions provided by this embodiment. The adjusted parameter is the period P of the phase-change Bragg grating 30, and the other structural parameters are: W=900nm, S=320nm, T=170nm, dc=0.15, N=100. The adjustment period P is 339nm, 342nm, and 345nm respectively. It can be seen that the transmission spectrum gradually redshifts with the increase of P, realizing that the Bragg-like resonance wavelength in the C band can be arbitrarily adjusted in the two states of the filter.

[0046] Example 3

[0047] See attached Figure 8 , Figure 8 It reflects the parameter tuning result of the multi-parameter tunable filter based on the phase-change Bragg grating under the conditions provided by this embodiment. The duty cycle dc of the phase-change Bragg grating 30 is adjusted. The other structural parameters are: W = 900nm, S = 320nm, T = 170nm, P = 345nm, N = 100. The duty cycle dc of the phase-change Bragg grating 30 is adjusted to 0.13, 0.11, and 0.09 respectively. As dc increases, the transmission spectrum bandwidth increases accordingly. This is because the effective refractive index of the grating layer part Compared to the effective refractive index of the bare waveguide Reducing the duty cycle dc means reducing the average refractive index n of the GSST material. eff The proportion of , so the Bragg-like resonance wavelength will decrease, the image will shift to the left. At the same time, due to the reduction of the phase change material GSST, the absorption of light is reduced, the transmittance is increased and the half-height width is reduced.

[0048] Example 4

[0049] See attached Fig. 9 , Fig. 9 It reflects the parameter tuning result of the multi-parameter tunable filter based on the phase-change Bragg grating under the conditions provided by this embodiment. The thickness T of the phase-change Bragg grating 30 is adjusted, that is, the effective refractive index of the grating part of the structure is adjusted. The other structural parameters are: W = 900nm, S = 320nm, dc = 0.15, P = 345nm, N = 100. The thickness T of the phase-change Bragg grating 30 is adjusted to 80nm, 140nm, and 160nm respectively. eff Finally, the bare waveguide and the grating part need to be averaged, and the grating thickness is increased to increase the refractive index ratio of the grating part, resulting in a red shift of the Bragg-like resonance wavelength. At the same time, the volume of the phase change material GSST increases, so the transmittance shows a downward trend.

[0050] Example 5

[0051] See attached Fig.10 , Fig.10 It reflects the parameter tuning results of the multi-parameter tunable filter based on the phase change Bragg grating under the conditions provided in this embodiment. The grid number N of the phase change Bragg grating 30 is adjusted, and the other structural parameters are W=900nm, S=320nm, T=170nm, dc=0.15, and P=345nm. The number of grids N is adjusted to 50, 70, and 100. As can be seen from the figure, the absorption capacity of the phase change material GSST gradually manifests itself as N increases (50, 70, 100), and the light transmittance shows a downward trend regardless of whether it is crystalline or amorphous. This is easy to understand. The volume of the phase change material GSST in the device is increased. Since the phase change material GSST has a certain loss, the more material, the greater its absorption of light. The change in N does not change the periodic distribution of the refractive index, so the central wavelength does not change.

[0052] Example 6

[0053] See attached Figure 4 , Figure 4 This is a side view of the xoz surface of the improved grating cover layer of the device described in Example 1 in this embodiment. Compared with the grating cover layer in Example 1, the grating cover layer 40 in this embodiment covers the entire phase change Bragg grating 30, which will affect the refractive index distribution of the multilayer optical film structure and have a certain impact on the light transmittance. The method of making the phase change material GSST undergo a phase change is to heat the phase change material GSST to make it change phase, and heating will cause the phase change material to undergo thermal expansion or material melting and produce deformation. At this time, the grating cover layer 40 can stabilize the structure of the phase change Bragg grating 30 when the phase change occurs, so that it does not undergo excessive deformation. This can not only increase the number of times the phase change material GSST can be repeatedly excited to change phases, extend its life, but also provide better protection for it and prevent oxidation, etc. At this time, the corresponding structural parameters are: the width of the waveguide is W = 900nm, the thickness is S = 320nm, and the length is greater than 34.5μm (N*P); the width of the phase change Bragg grating 30 is W = 900nm, the thickness is T = 170nm, the duty cycle dc = 0.15, the number of gratings is N = 100, and the grating period is P = 345nm; the thickness of the grating cover layer 40 is 9nm.

[0054] See attached Fig.11 , Fig.11It reflects the light transmission spectrum of the multi-parameter tunable filter based on the phase change Bragg grating under the conditions provided by this embodiment. After the structure in Example 1 is changed, the morphology of the Bragg-like resonance peak does not change much, does not affect its bandpass and bandstop capabilities, and the side lobes are reduced. The change in the structure at this time does not change the grating layer, but a 9nm thick grating cover layer 40 is added to the original silicon waveguide part, which adds an additional 9nm of silicon dioxide to the refractive index of this part. The refractive index of silicon dioxide material is smaller than that of silicon, so the average refractive index n eff Changes will happen.

[0055] See attached Fig.12 , Fig.12 It reflects the parameter tuning results of the multi-parameter tunable filter based on the phase-change Bragg grating under the conditions provided by this embodiment. The period P of the phase-change Bragg grating 30 is adjusted to 345nm, 346nm, and 347nm. When P=0.346μm, the Bragg-like resonance wavelength can be moved to 1.550μm. The insertion loss of the GSST device in the amorphous state is -15.2596dB, and the insertion loss in the crystalline state is -2.2445dB.

[0056] Example 7

[0057] In Example 1, various parameters of the GSST grating part are tuned. In Example 6, the overlap of the Bragg-like center wavelengths of the passband and the stopband is obtained when the crystalline and amorphous switching states have a large refractive index difference. However, there is only one filter band at this time. The Fabry-Perot resonator (K.Markowski, et al., Linearly chirped tapered fiber-Bragg-grating-based Fabry-Perot cavity and its application in simultaneous strain and temperature measurement, Opt. Lett., 42 (2017) 1464-1467.) consists of two reflectors. The light of the wavelength that meets the resonance condition is continuously interfered and enhanced in the structure. This phenomenon has important applications in semiconductor lasers. For the grating structure, it has a certain reflection effect in certain bands. We regard the Bragg-like grating part in the structure of Example 1 as a reflector, and then add a grating module to form a structure similar to the Fabry-Perot (FP) resonant cavity. At this time, the transmittance result is the result of the joint action of the Bragg grating and the FP cavity. Adjusting N means changing the transmittance of the Bragg grating-like part, which is equivalent to changing the reflectivity at the FP cavity reflector. Next, changing the parameters of the grating module can control the number and intensity of the resonance peaks. This structure is called a phase-shift grating. The specific implementation method is introduced below.

[0058] See attached Fig.13 , Fig.13 The structure of the multi-channel filter equipped with phase-shift gratings in this embodiment is shown in FIG. 1 , and the number of gratings is actually greater. Figure 1 Compared with the GSST grating module, a grating module is added to one side, and the spacing between the two modules is a half-integer multiple of the period. In order to highlight the spacing between the grating modules, the number of grating grids is reduced, and the actual number of grids in the two parts of the grating module is 30. At this time, the corresponding structural parameters are W = 0.81μm, S = 0.32μm, T = 0.16μm, dc = 0.15, N = 100, P = 0.354μm, and the thickness of the grating cover layer is 9nm.

[0059] See attached Fig.14 , Fig.14It reflects the transmission spectrum obtained under the conditions provided in this embodiment. As expected, the number of filter channels increases. In the range of 1540-1560nm, the phase change material has a bandpass segment with a central wavelength of 1.551μm and a half-width of 9nm when in an amorphous state, and its central insertion loss is -0.891dB. In the crystalline state, the central wavelength is 1.550μm, the half-width is 8nm, and there is a band-stop segment with an insertion loss of -18.245dB. This band-stop-bandpass-band-stop characteristic has application prospects in filters.

[0060] Example 8

[0061] Based on Example 7, the spacing between grating modules is adjusted to further increase the number of filtering channels.

[0062] See attached Fig.15 , Fig.15 The structure of the multi-channel filter equipped with phase-shift gratings under the conditions provided by this embodiment is reflected. In order to make the image clear, the number of gratings is actually 30. Figure 1 Compared with the conventional grating module, a grating module is added to one side of the GSST grating module, and the spacing between the two modules is a half-integer multiple of the period. The corresponding parameters are S = 0.32μm, W = 0.81μm; P = 0.35μm, dc = 0.15, T = 0.16μm, N = N1 = 30, and the spacing between the two grating modules is 95.5*P.

[0063] See attached Fig.16 , Fig.16 The result of a transmission spectrum of this embodiment is reflected. At this time, the insertion loss at the central wavelength of 1.540 μm is as low as -0.2379 dB, and FWEM = 3.4 nm. It can be seen that the number of passband and stopband in the C band in the spectrum is further increased, which is consistent with the expected purpose.

[0064] In summary, the phase change Bragg grating of the present invention adopts the phase change material GSST, and utilizes the optical properties of the phase change material GSST to have two optical pass characteristics, namely, passband and stopband, without changing the device structure. Moreover, the refractive index distribution of the phase change Bragg grating can be changed by adjusting various parameters of the filter, thereby realizing the adjustment of the number of filter channels and the tunability of the transmittance bandwidth, so that it can be widely used in the field of optical communications.

[0065] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A multi-parameter tunable filter based on a phase-change Bragg grating, characterized in that: The invention comprises a substrate, a waveguide, a phase-change Bragg grating and a grating cover layer, wherein the waveguide is arranged on the substrate, the phase-change Bragg grating is arranged on the waveguide, and the grating cover layer is arranged on the phase-change Bragg grating, wherein the phase-change Bragg grating adopts a phase-change material GSST; the substrate adopts silicon dioxide; the waveguide adopts silicon; the grating cover layer adopts silicon dioxide; the width of the waveguide is 810nm-900nm, and its width / thickness ratio is 2.5-2.8; the duty cycle of the phase-change Bragg grating is 0.15-0.19, the number of its periods is 30-100, the thickness is 80nm-170nm, the period is 332nm-355nm, and the thickness of the grating cover layer is 1-9nm.

2. The multi-parameter tunable filter based on phase-change Bragg grating according to claim 1, characterized in that: The grating cover layer completely covers the phase change Bragg grating.

3. The multi-parameter tunable filter based on phase-change Bragg grating according to claim 1, characterized in that: The grating cover layer only covers the top of the phase change Bragg grating.

4. The multi-parameter tunable filter based on phase-change Bragg grating according to claim 2 or 3, characterized in that: When the incident light of the waveguide is in the quasi-TE0 mode, the effective refractive index is 2.92-2.95 when the wavelength of the light is 1550 nm.

5. A control method for a multi-parameter tunable filter based on a phase-change Bragg grating as claimed in claim 4, characterized in that: include: When the incident light of the waveguide is in the quasi-TE0 mode, by adjusting the number of periods of the phase change Bragg grating, the phase change material GSST can be in an amorphous state to achieve a stop band with an adjustable minimum light transmittance in the range of 0.03~0.13, and the phase change material GSST can be in a crystalline state to achieve a pass band with an adjustable maximum light transmittance in the range of 0.55~0.

7.

6. The control method of the multi-parameter tunable filter based on the phase-changing Bragg grating according to claim 5 is characterized in that: include: When the incident light of the waveguide is in the quasi-TE0 mode, the period of the phase change Bragg grating is adjusted in the adjustment range of 332nm~355nm, so that the stop band and pass band of the phase change material GSST in the amorphous state and the crystalline state can be arbitrarily adjusted in the band of 1530~1565nm.

7. The control method of the multi-parameter tunable filter based on the phase-changing Bragg grating according to claim 5, characterized in that: include: When the incident light of the waveguide is in the quasi-TE0 mode, the thickness and duty cycle of the phase change Bragg grating are adjusted so that the bandwidth of the stop band and the pass band of the phase change material GSST can be adjusted in the amorphous state and the crystalline state.

8. The control method of the multi-parameter tunable filter based on the phase-change Bragg grating according to claim 5, characterized in that: include: When the incident light of the waveguide is in the quasi-TE0 mode, the number of channels can be tuned by changing the number of the phase-change Bragg gratings and the spacing between adjacent phase-change Bragg gratings.

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