CN103364872A - Composite waveguide device capable of realizing light blocking effect - Google Patents

Abstract

The invention discloses a composite waveguide device capable of realizing the light blocking effect and a preparation method thereof. The composite waveguide device capable of realizing the light blocking effect includes a glass substrate and the upper surface layer of the glass substrate is prepared by selective secondary ion exchange technology The ion-exchange strip waveguide whose thickness changes and the refractive index is gradually changed; the ion-exchange strip waveguide is an input waveguide, a composite waveguide, and an output waveguide from left to right, and the composite waveguide is composed of a cut-off waveguide and an As in the window area of the metal Al film. Multi-mode strip waveguide of 632.8nm wavelength light wave composed of ₂ S ₈ films; input waveguide and output waveguide are connected to each other through cut-off waveguide, and both input waveguide and output waveguide are ion-exchanged single-mode strip waveguide of 632.8nm wavelength light wave; cut-off waveguide It is cut off for 632.8nm wavelength light wave. The composite waveguide device capable of realizing the light blocking effect of the present invention can not only effectively realize the light blocking effect, but also realize good connection with the optical fiber.

Description

A Composite Waveguide Device Realizing Light Blocking Effect

technical field

The invention relates to a composite waveguide device capable of realizing light blocking effect, and belongs to the technical field of integrated optics and optical waveguide.

Background technique

Arsenic sulfide amorphous semiconductor has good transparency in the infrared band, and its optical nonlinear effect is two orders of magnitude higher than that of quartz glass, so it has attracted attention as a long-wavelength nonlinear optical medium. Among them, the average coordination number of As ₂ S ₃ amorphous semiconductor is very close to the critical coordination number, and the structure and chemical properties are relatively stable. Optical Kerr effect switches and optical nonlinear loop mirrors are realized on As ₂ S ₃ glass fibers etc. have been reported (Bureau B et al: J. Non-Cryst. Solids., Vol.345&346, p.276, 2004; Hocde S et al: J. Non-Cryst. Solids., Vol.274, p.17, 2000; Nishii J et al: J. Non-Cryst. Solids., Vol.140, p.199, 1992; Asobe M et al: J. Appl. Phys., Vol.77, p.5518, 1995; Troles J et al: Opt. Mater., Vol.25, p.231, 2004; Asobe M et al.: Opt. Lett., Vol.18, p.1056, 1993; Asobe M et al.: Electron. Lett., Vol.32, p.1396 , 1996). Compared with As ₂ S ₃ , As ₂ S ₈ has a lower average covalent bonding number in the amorphous structure, and is an underconstrained soft glass semiconductor (Lyubin V M et al.: J Non Crystalline Solids, Vol.135, p.37, 1991), the concentration of chemical bond defect states formed by abnormal electronic configurations is relatively high, and there are several sub-energy levels in the energy gap (PKGupta: J. Non Crystalline Solids, Vol. 195, p.158, 1996). Utilizing the absorption of signal light by sub-level electronic transitions, we report the light-blocking experiment of light-light effect on As ₂ S ₈ thin films and As ₂ S ₈ waveguides prepared by photoexcitation method (L.Zou, B.Chen et al.: Appl. Phy. Lett., Vol. 88, p.153510-1, 2006), this is a unique phenomenon of As ₂ S ₈ and cannot be observed in As ₂ S ₃ . The two ends of the As ₂ S ₈ waveguides must be connected with the optical fiber to form a practical device. This connection involves the end-face coupling between the guided wave in the optical waveguide and the guided wave in the optical fiber. In addition to the matching of the mode field distribution of the two guided waves, the end-face coupling efficiency is also related to the spatial relative orientation between the optical axes of the two guided waves. Ideally, the optical axes of the two guided waves are strictly aligned in space. and keep parallel. For this reason, the waveguide end face and fiber end face must be ground and polished before docking. Experiments show that the conventional optical-grade grinding and polishing process cannot be applied to As ₂ S ₈ , because As ₂ S ₈ is not resistant to alkali, and cannot pass the barrier of alkaline solution in multiple processes. Because the quality of the end faces of the As ₂ S ₈ waveguides is not up to standard, it becomes very difficult to improve the coupling efficiency of the end faces of the waveguides and optical fibers.

Contents of the invention

One of the purposes of the present invention is to solve the problem that the end faces of the As ₂ S ₈ waveguides are difficult to grind and polish, resulting in low coupling efficiency between the waveguide and the optical fiber end faces, a composite waveguide that can realize the light blocking effect is proposed and experimentally studied Devices and methods of making them.

Technical principle of the present invention

A compound waveguide device capable of realizing the light blocking effect, the device is a coupling structure of the compound waveguide, input waveguide and output waveguide.

The composite waveguide is composed of an ion-exchanged glass cut-off waveguide, a metal isolation layer and an As ₂ S ₈ thin film. The composite waveguide excites multi-mode transmission, and the mode field distribution is mainly concentrated in the As ₂ S ₈ thin film, so that the light can be effectively realized. blocking effect;

The input and output ends of the composite waveguide are coupled with the ion-exchange glass single-mode strip waveguide by using the principle of multi-mode interference, and the composite waveguide and the ion-exchange glass single-mode strip waveguide are integrated on the same base to form a composite waveguide device;

Since the input waveguide and output waveguide of the composite waveguide device are both single-mode strip waveguides of ion-exchanged glass, conventional grinding and polishing techniques can be used to process the end face of the waveguide. The composite waveguide device achieves the effect of not only effectively realizing the light blocking effect, but also being well connected with the optical fiber.

Technical scheme of the present invention

A composite waveguide device capable of realizing the light-blocking effect, comprising a glass substrate and an ion-exchange bar waveguide with a thickness-varying refractive index gradient prepared by selective secondary ion-exchange technology on the upper surface of the glass substrate;

The ion-exchange strip waveguide is an input waveguide, a composite waveguide and an output waveguide from left to right;

The composite waveguide is a multimode strip waveguide of 632.8nm wavelength light wave, and the multimode strip waveguide is the cut-off waveguide and the _As2S8 thin film located in the window area of the metal Al film upwards from the upper surface of the glass substrate _;

m，与截止波导直接接触的As₂S₈薄膜的厚度优选为1.7

m； The thickness of the above-mentioned window metal Al film is preferably 1.9

m, the thickness of the _As2S8 film in direct contact with _the cut-off waveguide is preferably 1.7

m;

The window opening area of the metal Al film is in the middle of the metal Al film, and corresponds to the top of the cut-off waveguide. On the window opening area of the metal Al film, the As ₂ S ₈ thin film is directly in contact with the upper surface of the cut-off waveguide , the length of the window area on the metal Al film is consistent with the length of the metal Al film and the length of _{the As2S8} film, preferably 4.17mm;

The width of the window area on the metal Al film is 2W, where W is called the half-width of the window area in technical terms;

The input waveguide and the output waveguide are connected to each other through the cut-off waveguide in the composite waveguide, and the input waveguide, the output waveguide and the cut-off waveguide in the composite waveguide have the same width;

m，L₂优选为0.8

m，L₃优选为3mm；其中输入波导与截止波导之间、以及输出波导与截止波导之间的长度为L₂的过渡区域通过离子交换侧向扩散自然形成，长度L₂与离子交换温度和时间有关，约为1

m量级； The length of the As ₂ S ₈ thin film in the composite waveguide is L ₃ +2 (L ₁ +L ₂ ), where L ₁ is the overlap between the window opening area of the input waveguide or output waveguide and the metal Al film The length of the region, L ₂ is the length of the transition region between the input waveguide or output waveguide and the cut-off waveguide, L ₃ is the length of the cut-off waveguide, wherein L ₁ is preferably 575

m, _L2 is preferably 0.8

m, _L3 is preferably 3mm; wherein the transition region between the input waveguide and the cut-off waveguide and between the output waveguide and the cut-off waveguide is naturally formed by ion _exchange lateral diffusion, and the length _L2 is related to the ion exchange temperature and time dependent, about 1

m level;

The above-mentioned input waveguide and output waveguide are both ion-exchanged single-mode bar waveguides with a wavelength of 632.8nm;

The above-mentioned cut-off waveguide is cut-off for the 632.8nm wavelength light wave, and does not support the guided mode transmission of the 632.8nm wavelength light wave, and the above-mentioned composite waveguide formed by the cut-off waveguide is a multi-mode strip waveguide of the 632.8nm wavelength light wave;

m； The windowed area of the metal Al film corresponds to the top of the cut-off waveguide. In the windowed area of the metal Al film, the As ₂ S ₈ film is directly in contact with the upper surface of the cut-off waveguide. The width of the windowed area is 2W, and the width of the windowed area is The length is consistent with the length of the metal Al film and the length of the As ₂ S ₈ film, and the width 2W of the window area is preferably 5

m;

The glass substrate is B270 optical glass, BK7 optical glass or K9 optical glass.

The above-mentioned composite waveguide device that can realize the light-blocking effect, due to the isolation effect of the metal Al film, the As ₂ S ₈ film on the metal Al film has no effect on the optical waveguide, so the above-mentioned one can realize light-blocking The composite waveguide in the composite waveguide device of the effect is a multimode strip waveguide. The incident light with a wavelength of 632.8nm excites the fundamental mode transmission in the input waveguide, and excites the multimode at the incident end of the composite waveguide. After the multimode interference transmission with the length of _L1 , the mode phase adjustment in the _L2 area, the light wave is coupled to the L ₃ area, and the light field distribution is mainly concentrated in the As ₂ S ₈ thin film. L ₃ is designed to be the mirror image distance of the input light field. Due to the symmetry of the optical path structure, according to the reciprocity principle, the light wave is coupled to the output waveguide after passing through the composite waveguide.

The various technical parameters of the above-mentioned composite waveguide device that can realize the light blocking effect are obtained through optimized design. The design considers the use of ion exchange technology to prepare glass strip waveguides. The optional glass substrates include optical glass such as B270, BK7 or K9. The present invention preferably adopts B270 optical glass of SCHOTT company, the ion source is 0.08% AgNO ₃ -99.92% NaNO ₃ mixed salt, and the molar ratio of Ag ⁺ is 0.0398%.

和表面折射率增量

是由Ag⁺摩尔比和离子交换温度T决定的近似常数，T=350℃时，

，

，折射率分布可表示为： Experiments and theoretical analysis confirmed that when the molar ratio of Ag ⁺ is less than 0.05%, the diffusion coefficient

and the surface refractive index increment

is an approximate constant determined by the molar ratio of Ag ⁺ and the ion exchange temperature T, when T=350°C,

,

, the refractive index distribution can be expressed as:

  (1)               

(1)

Here, x and y are the coordinates of the width and depth of the ion-exchange strip waveguide cross-section, respectively;

是B270光学玻璃基板的折射率；

is the refractive index of the B270 optical glass substrate;

是作为上包层的空气的折射率；

is the refractive index of air as the upper cladding;

是金属掩膜开窗的宽度；

is the width of the metal mask opening;

是有效扩散深度；

is the effective diffusion depth;

是离子交换时间。

is the ion exchange time.

m，离子交换时间是60min，有效扩散深度d_eff=2.43

m，对632.8nm波长构成单模波导。 The width 2W of the window area of the ion exchange strip waveguide is designed to be 5

m, ion exchange time is 60min, effective diffusion depth d _eff =2.43

m, constitutes a single-mode waveguide for a wavelength of 632.8nm.

m。截止波导的上表面的开窗金属Al膜的厚度是1.9

m，复折射率是1.2-i7.0（

=632.8nm）。截止波导上和金属Al膜上覆盖As₂S₈薄膜构成复合波导，As₂S₈薄膜的厚度取1.7

m，直接覆盖在截止波导上表面的As₂S₈薄膜的宽度由金属Al膜的5

m开窗宽度限定，设计取L₂为0.8

m，As₂S₈薄膜的折射率是2.3065（

=632.8nm）。 The structure design takes the above-mentioned single-mode waveguide as the input waveguide and output waveguide. For the cut-off waveguide, except that the ion exchange time is shortened to 20min, other parameters are the same as those of the input waveguide and output waveguide. The effective diffusion depth of the cut-off waveguide d _eff =1.40

m. The thickness of the windowed metal Al film that cuts off the upper surface of the waveguide is 1.9

m, the complex refractive index is 1.2-i7.0 (

=632.8nm). The cut-off waveguide and the metal Al film are covered with As ₂ S ₈ film to form a composite waveguide, and the thickness of the As ₂ S ₈ film is 1.7

m, the width of the As ₂ S ₈ film directly covering the upper surface of the cut-off waveguide is divided by the metal Al film 5

The window opening width is limited by m, and _L2 is designed to be 0.8

m, the refractive index of the As ₂ S ₈ film is 2.3065 (

=632.8nm).

The above design results show that the optimized selection of the parameters of the composite waveguide can provide sufficient dimensional error tolerance for process fabrication.

The above-mentioned preparation method of a composite waveguide device capable of realizing the light blocking effect specifically includes the following steps:

(1), pretreatment of glass substrate

The cleaning of the glass substrate adopts the brushless scrubbing method of ultrasonic vibration cavitation combined with chemical reaction, that is, cleaning with a neutral detergent with a pH value of 7 for 5 minutes, 3 times of pure water for 1 minute, acetone for 5 minutes, and 2 times of pure water 1min, wash with absolute ethanol for 3min, wash with IPA for 2min, dry the surface with nitrogen, and then dry at 130°C for 30min;

(2) Selective secondary ion exchange technology is used to prepare ion-exchange bar waveguides with thickness-changing refractive index gradients. The ion-exchange waveguide is prepared using Ag ⁺ -Na ⁺ ion exchange technology

m，金属Al薄膜覆盖整个玻璃基板的上表面，金属Al薄膜的开窗采用常规光刻技术，开窗区域的宽度为2W，即2W优选为5

m，开窗区域露出玻璃基板的上表面，L₃=3mm 的区域被金属Al薄膜遮蔽； ①. On the upper surface of a clean and dry glass substrate with a length of 15 mm, a metal Al film is prepared by conventional thermal evaporation vacuum coating technology, and its thickness is preferably 1.9

m, the metal Al film covers the upper surface of the entire glass substrate, and the window opening of the metal Al film adopts conventional photolithography technology, and the width of the window area is 2W, that is, 2W is preferably 5

m, the window area exposes the upper surface of the glass substrate, and the area of L ₃ =3mm is covered by the metal Al film;

②. Perform the first ion exchange. The ion source for the first ion exchange is 0.08% AgNO ₃ -99.92% NaNO ₃ mixed molten salt, the ion exchange temperature is 350°C, and the constant temperature time is 40 minutes;

m，开窗区域露出玻璃基板的上表面； ③. Use conventional photolithographic overlay technology to open the window to open the L ₃ area. The width of the window area is 2W, that is, 2W is preferably 5

m, the window area exposes the upper surface of the glass substrate;

④. Carry out the second ion exchange, the ion source and ion exchange temperature are the same as those of the first ion exchange, and the constant temperature time is 20 minutes. At this time, the ion exchange single-mode strip waveguide as the input waveguide and output waveguide is formed and used to construct composite The length of the waveguide is _L3 cut-off waveguide;

(3) Use conventional photolithographic overlay technology to remove the metal Al films on both sides of the input waveguide and output waveguide, and the length of the remaining window-opened metal Al films is L ₃ +2 (L ₁ +L ₂ ), preferably 4.17 mm;

m，在金属Al膜的开窗区域，As₂S₈薄膜直接与截止波导的上表面接触，即得可实现光阻断效应的复合波导器件。 (4) After shielding the exposed area of the glass substrate with a sharp blade, use conventional thermal evaporation vacuum coating technology to vacuum-deposit As ₂ S ₈ film on the retained metal Al film with a window, and its thickness is preferably 1.7

m, In the window area of the metal Al film, the As ₂ S ₈ film is directly in contact with the upper surface of the cut-off waveguide, and a composite waveguide device that can realize the light-blocking effect is obtained.

The above-mentioned composite waveguide device capable of realizing light blocking effect can be applied in such as realizing optical pulse coupling function because it can realize non-saturated light blocking operation.

Beneficial effects of the present invention

The light-blocking effect is a unique light-light interaction phenomenon of As ₂ S ₈ . In order to construct an optical waveguide device with light-blocking effect, As ₂ S ₈ waveguides must be prepared. The prior art that has been reported is in As ₂ S ₈ waveguides were fabricated on As ₂ S ₈ film by photorefractive technology excited by ultraviolet light, and the light blocking effect was realized. In order to connect the As ₂ S ₈ waveguides with external systems such as light sources and detectors to form a practical device, the two ends of the As ₂ S ₈ waveguides must be connected and cured with the input and output fibers in advance. This docking involves the mode end-face coupling between the guided wave in the optical waveguide and the guided wave in the optical fiber. The coupling efficiency of the mode end-face coupling is not only related to the matching of the mode field distribution of the two guided waves participating in the coupling, but also related to the two The spatial relative orientation between the optical axes of the two guided waves is related. Ideally, the optical axes of the two guided waves are strictly aligned in space and kept parallel. For this reason, grinding and polishing of As ₂ S ₈ waveguide end faces and fiber end faces must be carried out before butt jointing and curing. Experiments have shown that the conventional optical-grade grinding and polishing process cannot be applied to the end face grinding and polishing of As ₂ S ₈ waveguides, because the As ₂ S ₈ material is not resistant to alkali and cannot pass the corrosion of alkaline solutions in the multiple processes of grinding and polishing, resulting in The two end faces of the As ₂ S ₈ waveguides are uneven, and in severe cases, there will be damaged gaps. Because the quality of the end faces of the As ₂ S ₈ waveguides processed by the current grinding and polishing technology is not satisfactory, it becomes very difficult to improve the coupling efficiency of the As ₂ S ₈ waveguides and the end faces of the optical fiber.

A composite waveguide device capable of realizing the light blocking effect of the present invention adopts a glassy ion-exchange single-mode bar waveguide as the input waveguide and output waveguide at the input and output ends of the device, and the grinding and polishing of both ends does not involve As ₂ For _S8 material, the current grinding and polishing technology of glass materials can be used to obtain a flat and good end face. One of the beneficial effects of the present invention is to solve the problem of end face quality required for butt coupling.

However, there is currently no current scheme for reference on how to achieve effective homogeneous integration of the two ion-exchanged single-mode bar waveguides as the input waveguide and output waveguide with the As ₂ S ₈ waveguide with light blocking effect on the same substrate. The difficulty is that the effective realization of the light blocking effect requires that the working light wave must be confined in the As ₂ S ₈ waveguide or thin film as much as possible. How efficient is the light-guided mode in the two ion-exchanged single-mode bar waveguides used as the input waveguide and the output waveguide? The ground coupling in and out of the As ₂ S ₈ waveguide or thin film is the key technology. The present invention proposes and realizes a composite waveguide structure composed of a cut-off waveguide and an As ₂ S ₈ film located in the windowed area of the metal Al film. The composite waveguide can exchange single-mode The homogeneous integration of strip waveguides, the multi-mode interference principle between the composite waveguide and the input waveguide and the output waveguide realizes low-loss, high-efficiency optical wave transmission coupling, thus the second beneficial effect of the present invention is to solve the problem of the input waveguide and output waveguide Two vitreous ion-exchanged single-mode bar waveguides of the waveguide and the As ₂ S ₈ waveguide with light-blocking effect realize effective homogeneous integration on the same substrate.

In a word, a composite waveguide device capable of realizing the light blocking effect of the present invention achieves the beneficial effect of not only effectively realizing the light blocking effect, but also being well connected with the optical fiber.

Description of drawings

Figure 1a, a schematic plan view of the composite waveguide device capable of realizing the light blocking effect of Example 1;

The sectional view along B-B direction among Fig. 1b, Fig. 1a;

A sectional view along A-A direction among Fig. 1c and Fig. 1a;

The schematic diagram of the pattern of the metal Al film used for the first ion exchange obtained in the preparation process of the composite waveguide device that can realize the light blocking effect of Fig. 2a, embodiment 1;

The schematic diagram of the pattern of the metal Al film used for the second ion exchange obtained in the preparation process of the composite waveguide device that can realize the light blocking effect of Fig. 2b, embodiment 1;

Figure 2c, the schematic diagram of the pattern after depositing the As ₂ S ₈ film obtained during the preparation of the composite waveguide device that can realize the light blocking effect in Example 1 after removing the metal Al film on both sides of the input waveguide and output waveguide ;

Fig. 3, the local photomicrograph of composite waveguide 7 in a kind of composite waveguide device that can realize light blocking effect obtained in embodiment 1;

Figure 4. Schematic diagram of the structure of the device for testing the light blocking experiment of the composite waveguide device that can realize the light blocking effect;

Fig. 5, the light blocking experiment result of a kind of composite waveguide device that can realize light blocking effect obtained in embodiment 1;

₁与L₁的关联情况； Figure 6. The coupling efficiency related to the composite waveguide in the composite waveguide device that can realize the light blocking effect obtained in Example 1 and obtained by beam propagation method (BPM) simulation

The relationship between ₁ and L ₁ ;

Figure 7. The coupling efficiency related to the composite waveguide in the composite waveguide device that can realize the light blocking effect obtained in Example 1 and obtained by beam propagation method (BPM) simulation The relationship between ₁ and L ₂ ;

₁与As₂S₈膜厚h的关联情况； Figure 8. Coupling efficiency related to the composite waveguide in the composite waveguide device that can realize the light blocking effect obtained in Example 1 and obtained by beam propagation method (BPM) simulation

₁ and the relationship between As ₂ S ₈ film thickness h;

Fig. 9. The correlation between the insertion loss of the composite waveguide and the _L3 obtained by the simulation of the beam propagation method (BPM) related to the composite waveguide in the composite waveguide device capable of realizing the light blocking effect obtained in Example 1;

m）； Figure 10a. The mode field distribution of the composite waveguide device that can realize the light blocking effect obtained from the simulation of the beam propagation method (BPM) changes along L ₃ (L ₃ =3300

m);

Figure 10b. The variation of the mode field distribution along L ₃ of the composite waveguide device that can realize the light blocking effect obtained by beam propagation method (BPM) simulation (L ₃ =3400 m);

m）； Figure 10c. The mode field distribution of the composite waveguide device that can realize the light blocking effect obtained from the simulation of the beam propagation method (BPM) changes along L ₃ (L ₃ =3500

m);

m）； Figure 10d. The mode field distribution of the composite waveguide device that can realize the light blocking effect obtained from the simulation of the beam propagation method (BPM) changes along L ₃ (L ₃ =3600

m);

FIG. 11 , the beam transmission method (BPM) simulation transmission result of the composite waveguide device capable of realizing the light blocking effect obtained in Example 1.

Detailed ways

The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings, but the present invention is not limited.

Example 1

A composite waveguide device capable of realizing the light-blocking effect, the schematic diagrams of which are shown in Figure 1a, Figure 1b and Figure 1c;

Fig. 1a is a top view of a composite waveguide device capable of realizing light-blocking effect. As can be seen from Fig. 1a, the composite waveguide device capable of realizing light-blocking effect includes a glass substrate 6 and adopts selective secondary ion exchange technology to prepare an ion-exchange strip waveguide with a graded refractive index that varies in thickness, and the ion-exchange strip waveguide is an input waveguide 1, a composite waveguide 7, and an output waveguide 2 from left to right;

Figure 1b is a schematic structural view of the section along the B-B direction in Figure 1a, as can be seen from Figure 1b:

m的As₂S₈薄膜43，截止波导3的长度是3mm,处于金属Al膜5的开窗区域内的As₂S₈薄膜43的长度与金属Al膜5的长度一样，均为4.17mm； The composite waveguide 7 is composed of the cut-off waveguide 3 and the _As2S8 thin film 43 in the window area of the metal Al film 5, and _the thickness of the cut-off waveguide 3 and the window area of the metal Al film 5 is sequentially from bottom to top. 1.7

m _As2S8 thin film 43, the length of the cut-off waveguide 3 is 3mm, the length of the _As2S8 thin film 43 in the window area of the metal _Al film 5 is the same as the _length of the metal Al film 5, which is 4.17mm;

The length of the composite waveguide 7 is L ₃ +L ₁ ′+L ₁ +L ₂ +L ₂ ′, where L ₁ =L ₁ ′, which is the opening between the input waveguide or output waveguide and the metal Al film The length of the overlapping area of the window area;

L ₂ =L ₂ ', is the length of the transition region between the input waveguide or output waveguide and the cut-off waveguide;

m，L₂=L₂’，为0.8

m，L₃为3mm； L ₃ is the length of the cut-off waveguide, where L ₁ =L ₁ ', which is 575

m, L ₂ =L ₂ ', is 0.8

m, _L3 is 3mm;

It can also be seen from FIG. 1b that the input waveguide 1 and the output waveguide 2 are connected to each other through the cut-off waveguide 3 in the composite waveguide 7;

Both the above-mentioned input waveguide 1 and output waveguide 2 are single-mode strip waveguides of light waves with a wavelength of 632.8nm;

The above-mentioned cut-off waveguide 3 is cut-off for the 632.8nm wavelength light wave, and does not support the guided mode transmission of the 632.8nm wavelength light wave, and the composite waveguide 7 formed by the cut-off waveguide is a multi-mode strip waveguide for the 632.8nm wavelength light wave;

Fig. 1c is a cross-sectional view along the AA direction in Fig. 1a. It can be seen from Fig. 1c that the window opening area of the metal Al film 5 is in the middle of the metal Al film 5, and corresponds to directly above the cut-off waveguide 3. In the windowed area of the film 5, the As ₂ S ₈ thin film is directly in contact with the upper surface of the cut-off waveguide 3, and the width 2W of the windowed area is 5 m, the length of the window area is consistent with the length of the metal Al film 5 and the length of the _As2S8 film 4, which is _4.17mm ;

The metal Al film 5 and the As ₂ S ₈ thin film 4 are arranged symmetrically with respect to the cut-off waveguide 3. After the metal Al film 5 is opened, the metal Al film 51, the metal Al film 52, and the As ₂ S ₈ thin film 41 shown in Figure 1b are formed. , As ₂ S ₈ thin film 42 and the As ₂ S ₈ thin film 43 in the window area of the metal Al film;

The aforementioned glass substrate 6 is B270 optical glass.

The above-mentioned preparation method of a composite waveguide device capable of realizing the light blocking effect specifically includes the following steps:

(1), pretreatment of glass substrate

The cleaning of B270 glass substrate 6 adopts the brushless scrubbing method of ultrasonic vibration cavitation combined with chemical reaction, that is, washing with a neutral detergent with a pH value of 7 for 5 minutes, 3 times of pure water for 1 minute, acetone for 5 minutes, and 2 times of pure water. Wash with water for 1 min, ethanol for 3 min, IPA for 2 min, nitrogen to dry the surface, and then dry at 130°C for 30 min;

(2) Using selective secondary ion exchange technology to prepare ion-exchange strip waveguides with thickness-varying refractive index gradients;

和表面折射率增量

用以下的方法实验确定： The ion exchange waveguide is prepared using Ag ⁺ -Na ⁺ ion exchange technology, and the diffusion coefficient of ion exchange

and the surface refractive index increment

Determined experimentally using the following method:

和表面折射率增量

是由Ag⁺摩尔比和离子交换温度T决定的近似常数。实验采用的离子交换温度恒定为350℃，交换时间分别取4.5h、3.5h、2.5h和1.5h制备了四片多模的折射率渐变离子交换波导，在632.8nm波长下，用棱镜耦合技术（R. Ulrich and R. Torge：Appl. Opt，Vol.12，p.2901, 1973）测得各阶横向电场导模（TE导模）的传播常数，利用迭代拟合法得到的扩散系数

和表面折射率增量

列于下表： The ion source is 0.08% AgNO ₃ -99.92% NaNO ₃ mixed molten salt, and the molar ratio of Ag ⁺ is 0.0398%. When the molar ratio of Ag ⁺ is less than 0.5%, the diffusion coefficient

and the surface refractive index increment

is an approximate constant determined by the Ag ⁺ molar ratio and the ion exchange temperature T. The ion exchange temperature used in the experiment was constant at 350°C, and the exchange time was 4.5h, 3.5h, 2.5h, and 1.5h respectively to prepare four multi-mode ion-exchange waveguides with graded refractive index. At a wavelength of 632.8nm, the prism coupling technique was used (R. Ulrich and R. Torge: Appl. Opt , Vol.12, p.2901, 1973) measured the propagation constants of each order transverse electric field conduction mode (TE conduction mode), and the diffusion coefficient obtained by iterative fitting method

and the surface refractive index increment

listed in the table below:

）和0.019,由此可以分别确定制备离子交换单模条波导和截止波导的离子交换恒温时间t; The above table shows the diffusion coefficient obtained by the experimental process conditions and the surface refractive index increment are about 4.09×10 ^-4 (

) and 0.019, from which the ion-exchange constant temperature time t for preparing ion-exchange single-mode bar waveguides and cut-off waveguides can be determined respectively;

m，开完窗之后即形成金属Al膜51、金属Al膜52，开窗的区域露出玻璃基板6的上表面，L₃=3mm的区域被金属Al薄膜5遮蔽，以确保第一次离子交换不涉及截止波导，即第一次开窗形成的Al薄膜51、金属Al膜52的示意图如图2a所示； ①. On the upper surface of the clean and dry B270 optical glass substrate 6 with a length of ¹⁵ mm, a thickness of 1.9 m, a metal Al film 5 with a length of 4.17mm, the metal Al film 5 covers the upper surface of the entire glass substrate 6, the window of the metal Al film 5 adopts conventional photolithography technology, and the width 2W of the window is 5

m, the metal Al film 51 and the metal Al film 52 are formed after the window is opened, the window area exposes the upper surface of the glass substrate 6, and the area of L ₃ =3mm is covered by the metal Al film 5 to ensure the first ion exchange The schematic diagram of the Al thin film 51 and the metal Al film 52 formed by opening the window for the first time without involving the cut-off waveguide is shown in FIG. 2 a ;

②. Perform the first ion exchange. The ion source for the first ion exchange is 0.08% AgNO ₃ -99.92% NaNO ₃ mixed molten salt, the ion exchange temperature is 350°C, and the constant temperature time is 40 minutes;

m，开窗区域露出玻璃基板6的上表面，即第二次开窗形成的Al薄膜51、金属Al膜52的示意图如图2b所示； ③. Use conventional photolithography overlay technology to open the window to open the L ₃ area, and the window width is 2W to 5

m, the upper surface of the glass substrate 6 is exposed in the window opening area, that is, the schematic diagram of the Al thin film 51 and the metal Al film 52 formed by opening the window for the second time is shown in Figure 2b;

④. Carry out the second ion exchange, the ion source and ion exchange temperature are the same as the first ion exchange, and the constant temperature time is 20min. At this time, the ion exchange single-mode bar waveguide as the input waveguide 1 and output waveguide 2 is formed and used for The length of constructing composite waveguide is the cut-off waveguide 3 of L ₃ ;

(3) The metal Al films on both sides of the input waveguide 1 and the output waveguide 2 are removed by conventional photolithographic overlay technology, and the lengths of the remaining metal Al films 51 and 52 are both 4.17mm;

m的As₂S₈薄膜，并保证形成的As₂S₈薄膜41、As₂S₈薄膜42以及在金属Al膜的开窗位置的As₂S₈薄膜43其长度均为4.17mm，即得可实现光阻断效应的复合波导器件，去除了输入波导1和输出波导2两侧的金属Al薄膜后，淀积了As₂S₈薄膜后的图案示意图如图2c所示。 (4) After shielding the exposed area of the glass substrate with a sharp blade, use conventional thermal evaporation vacuum coating technology (vacuum degree: 5×10 ^-6 Pa, evaporation current: 40A) with a vacuum deposition thickness of 1.7

m As ₂ S ₈ thin film, and ensure that the formed As ₂ S ₈ thin film 41, As ₂ S ₈ thin film 42 and the As ₂ S ₈ thin film 43 at the window position of the metal Al film are all 4.17mm in length, namely The composite waveguide device that can realize the light blocking effect, after removing the metal Al film on both sides of the input waveguide 1 and output waveguide 2, the pattern diagram after depositing the As ₂ S ₈ film is shown in Figure 2c.

m，彼此没有任何光学干扰。 The local position of the compound waveguide device that can realize the light-blocking effect obtained above, that is, the composite waveguide 7, is photographed with a BM-17 phase contrast microscope of Shanghai Optical Instrument No. 6 Factory. The resulting picture is shown in Figure 3. The root waveguide is a backup waveguide prepared by the same method as above to prevent test errors, and the spacing between the backup waveguide and the waveguide of the composite waveguide device is as wide as 80

m, without any optical interference with each other.

The light blocking effect of the composite waveguide device that can realize the light blocking effect obtained in the above embodiment 1 is tested, and the structural diagram of the test device is shown in Figure 4, and the two ends of the composite waveguide device that can realize the light blocking effect After grinding and polishing, they are respectively coupled with the end face of a 632.8nm single-mode optical fiber. The optical fiber at the coupling end is inserted into a quartz glass capillary and then bonded and solidified. After grinding, it forms a conventional single-core array.

One end of the single-mode fiber at the input end is connected to a He-Ne laser with a wavelength of 632.8nm, and the other end is docked and coupled with the input end of the input waveguide 1 of the composite waveguide device;

One end of the single-mode optical fiber at the output end is butt-coupled with the output end of the output waveguide 2 of the composite waveguide device, and the other end is connected with the optical power meter.

The butt coupling of the input single-mode fiber-composite waveguide device-output single-mode fiber optical path system adopts automatic core adjustment technology. In order to reduce Fresnel reflection, the refractive index matching liquid (MORITEX company) is filled between the end face of the fiber and the end face of the composite waveguide device Product MO-633, the transmittance of 632.8nm wavelength light wave is 99%/mm). The He-Ne laser with a wavelength of 632.8nm is coupled through the input single-mode fiber to excite the guided mode of the composite waveguide device that can realize the light blocking effect. A regular oscilloscope record shows. The bandgap light is a He-Cd laser with adjustable power at 441.6nm wavelength, coupled and guided by a multimode fiber, and irradiates the As ₂ S ₈ film from the surface of the sample, and the beam irradiation radius is about 2mm. The shutter switch is used to control the irradiation time of the He-Cd laser with a wavelength of 441.6nm on the As ₂ S ₈ film of the composite waveguide device which can realize the light blocking effect through the multimode fiber.

In the case of cutting off the 441.6nm wavelength He-Cd laser irradiation, measure the output power of the 632.8nm wavelength light wave of the above-mentioned optical path with an optical power meter, and obtain the 632.8nm of the composite waveguide device that can realize the light blocking effect obtained in Example 1. The insertion loss of wavelength light wave is 1.8dB.

The light blocking effect shows that the transmission of the 632.8nm waveguide mode is cut off at the 441.6nm wavelength He-Cd laser irradiation, and the 632.8nm waveguide mode resumes transmission when the 441.6nm wavelength He-Cd laser light irradiation is removed. The dynamic process can be explained as the shallow-level polaritons self-trapped electrons transported by short-wavelength bandgap light constitute the absorption of long-wavelength signal photons, and the degree of absorption of long-wavelength signal light is related to the self-trapping energy pumped into the gap Therefore, the cut-off depth of the 632.8nm signal light is related to the number of photons of the 441.6nm bandgap light.

Figure 5 is the test result of the light blocking effect of the composite waveguide device, the abscissa is the transmission time, the ordinate is the transmission power of the 632.8nm signal light, and the optical power of the He-Cd laser is 14mW, as can be seen from Figure 5, once When the He-Cd laser is turned on and irradiated, the transmission of the 632.8nm signal light is blocked. With the continuous irradiation of the He-Cd laser, the concentration of electrons pumped to the self-trap energy level in the gap reaches saturation, and the 632.8nm signal light transmission is deeply blocked. At this time, the He-Cd laser irradiation is cut off, and the transmission of the 632.8nm signal light gradually returns to the original state.

₁与L₁的长度相关，在L₁=575m附近，有90%以上的最大耦合效率，且对L₁变动有很好的脱敏性。过渡区L₂由侧向扩散自然形成，长度约为1

m量级，图7的波束传输法（BPM）的仿真结果显示L₂在0.5～2.0

m范围内变动时

₁几乎不变。这个结果提示对离子交换侧向扩散的控制是宽容的。由于在复合波导7的入口处发生了折射率分布的突变，辐射模的激发是难以避免的，耦合效率

₁与As₂S₈薄膜43的厚度h也有关，图8给出了波束传输法（BPM）的仿真结果，As₂S₈薄膜43的膜厚h在1.68～1.77

m范围内可以获得约为91%的耦合效率，提供了约为0.1

m的膜厚控制允差。 The coupling efficiency of the input end of the composite waveguide in the composite waveguide device that can realize the light blocking effect obtained in the above-mentioned embodiment 1 is the ratio of the optical power of the _L3 area to the input optical power ₁ to characterize, the results are shown in Figure 6, Figure 6 is the simulation result obtained by beam propagation method (BPM) at 632.8nm wavelength,

₁ is related to the length of L _1. Around L ₁ =575m, there is a maximum coupling efficiency of more than 90%, and it has good desensitization to the change of L ₁ . The transition region _L2 is naturally formed by lateral diffusion with a length of about 1

On the order of m, the simulation results of the beam transmission method (BPM) in Figure 7 show that L ₂ is between 0.5 and 2.0

When changing within the range of m

₁ almost unchanged. This result suggests that the control of ion-exchange lateral diffusion is permissive. Due to the sudden change of the refractive index distribution at the entrance of the composite waveguide 7, the excitation of the radiation mode is unavoidable, and the coupling efficiency

₁ is also related to the thickness h of the As ₂ S ₈ thin film 43. Figure 8 shows the simulation results of the beam propagation method (BPM). The thickness h of the As ₂ S ₈ thin film 43 ranges from 1.68 to 1.77

A coupling efficiency of about 91% can be obtained in the m range, providing about 0.1

m film thickness control tolerance.

m、h=1.70

m的结构，进一步考察实施例1所得的可实现光阻断效应的复合波导器件的复合波导7的插入损耗与L₃的关联性，图9的波束传输法（BPM）的仿真结果显示，在围绕设计长度的±600

m跨度范围内，插入损耗维持在1dB左右。理论上，由于多模传输，L₃区域存在周期性变动的模场分布，本复合波导7结构提供的多模干涉的干涉对比度低，模场分布沿L₃的变动小，效果是插入损耗对L₃的变动几乎不敏感。 According to the above results, take L ₁ =575

m, h=1.70

The structure of m, and further investigate the correlation between the insertion loss of the composite waveguide 7 and _L3 of the composite waveguide device obtained in Example 1 that can realize the light blocking effect, and the simulation results of the beam propagation method (BPM) in Figure 9 show that, in ±600 around the design length

In the span range of m, the insertion loss is maintained at about 1dB. Theoretically, due to multi-mode transmission, there is a periodically changing mode field distribution in the _L3 area. The interference contrast of the multi-mode interference provided by the composite waveguide 7 structure is low, and the change of the mode field distribution along _L3 is small. The effect is that the insertion loss has a great influence on _L3 is almost insensitive to changes.

The simulation data of the beam propagation method (BPM) shows the partial screenshots of the mode field distribution of the guided mode of the composite waveguide 7 of the composite waveguide device obtained in Example 1 that can realize the light blocking effect along _L3 . 10b, 10c and 10d, it can be seen from Fig. 10a, 10b, 10c and 10d that the mode field distribution of the guided mode is mainly concentrated in the area of the As ₂ S ₈ thin film 43, and the mode field distribution is along the L ₃ changes are relatively small.

In summary, a composite waveguide device of the present invention that can realize the light blocking effect can well realize the butt coupling with the external input optical fiber and output optical fiber, and the insertion loss is 1.8dB. The control of irradiation can significantly realize the light blocking effect on the transmission of 632.8nm signal light.

The above content is only a basic description of the concept of the present invention, and any equivalent transformation made according to the technical solution of the present invention shall belong to the protection scope of the present invention.

Claims (3)

1. the composite waveguide device that can realize light blocking effect is characterized in that the described composite waveguide device of light blocking effect of realizing comprises a glass substrate and the ion-exchange bar waveguide of adopting selectivity secondary ion switching technology to prepare the gradually changed refractive index of variation in thickness at this glass substrate upper epidermis;

The waveguide of described ion-exchange bar from left to right is followed successively by input waveguide, composite waveguide and output waveguide;

Described composite waveguide is the multimode bar waveguide of 632.8nm wavelength light wave, and the waveguide of described multimode bar namely upwards is followed successively by cut-off waveguide and the As that is positioned at the windowed regions of Al metal membrane from the upper epidermis of glass substrate ₂S ₈Film;

The windowed regions of described Al metal membrane is in the middle of Al metal membrane, and corresponding to directly over the cut-off waveguide, at the windowed regions of Al metal membrane, As ₂S ₈Film directly contacts the length of the windowed regions of Al metal membrane and the length of Al metal membrane, As with the upper surface of cut-off waveguide ₂S ₈The length of film is consistent, and the width of windowing is 2W;

Cut-off waveguide in described input waveguide, output waveguide and the composite waveguide has identical width, and described input waveguide and output waveguide connect leading to mutually by the cut-off waveguide in the composite waveguide;

Described input waveguide and output waveguide are the ion-exchange single mode bar waveguide of 632.8nm wavelength light wave;

Described cut-off waveguide ends 632.8nm wavelength light wave, does not support the guided mode transmission of 632.8nm wavelength light wave;

Described glass substrate is B270 optical glass, BK7 optical glass or K9 optical glass.

2. a kind of composite waveguide device of realizing light blocking effect as claimed in claim 1 is characterized in that described Al metal membrane thickness of windowing is 1.9 ì m, As ₂S ₈Film thickness is 1.7 ì m;

As in the described composite waveguide ₂S ₈The length of film and Al metal membrane is L ₃+ 2(L ₁+ L ₂);

L wherein ₁Carry out the length of overlapping region for the windowed regions of described input waveguide or output waveguide and described Al metal membrane;

L ₂Length for the transitional region between described input waveguide or output waveguide and the described cut-off waveguide;

L ₃Length for cut-off waveguide;

L wherein ₁Be 575 ì m, L ₂Be 0.8 ì m, L ₃Be 3mm;

The width 2W of the windowed regions of Al metal membrane is 5 ì m;

As ₂S ₈The length of the windowed regions of the length of film, the length of Al metal membrane and Al metal membrane is 4.17mm.

3. a kind of preparation method who realizes the composite waveguide device of light blocking effect as claimed in claim 1 or 2 is characterized in that specifically comprising the steps:

(1), the pre-service of glass substrate

The cleaning of glass substrate adopts the ultrasonic vibration cavitation in conjunction with the brushless scrubbing method of chemical reaction, namely being followed successively by with the pH value is that 7 mild detergent cleaning 5min, 3 pure water cleaning 1min, acetone cleaning 5min, 2 pure water cleaning 1min, absolute ethyl alcohols cleaning 3min, IPA cleaning 2min, nitrogen dry up the surface, then in 130 ℃ of dry 30min;

(2), the ion-exchange bar waveguide of adopting selectivity secondary ion switching technology to prepare the gradually changed refractive index of variation in thickness, Ag is adopted in the ion-exchange waveguides preparation ⁺-Na ⁺Ion exchange technique

1., at the upper surface of the glass substrate of clean dried, adopt conventional thermal evaporation vacuum coating technology to prepare metal A l film, metal A l film covers the upper surface of whole glass substrate, conventional photoetching technique is adopted in windowing of metal A l film, the width of windowed regions is 2W, windowed regions is exposed the upper surface of glass substrate, L ₃The zone covered by metal A l film;

2., carry out the ion-exchange first time, the ion gun of for the first time ion-exchange is 0.08%AgNO ₃-99.92%NaNO ₃Mixed melting salt, ion-exchange temperature are 350 ℃, and constant temperature time is 40min;

3., adopt conventional photoetching cover lithography to window and get through L ₃Zone, the width of windowed regions are 2W, and windowed regions is exposed the upper surface of glass substrate;

4., carry out the ion-exchange second time, ion gun and ion-exchange temperature are identical with for the first time ion-exchange, constant temperature time is 20min, forming this moment as the ion-exchange single mode bar waveguide of input waveguide, output waveguide and the length that is used for the structure composite waveguide is L ₃Cut-off waveguide;

(3), adopt conventional photoetching cover lithography to remove the metal A l film of input waveguide and output waveguide both sides, the length of the windowed regions of the metal A l film of reservation is L ₃+ 2(L ₁+ L ₂);

(4), use blade preventing glass substrate with the sharp edge of a knife to expose the zone after, adopt conventional thermal evaporation vacuum coating technology vacuum deposition As ₂S ₈Film namely gets the composite waveguide device that can realize light blocking effect.

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