Application of Ge-Sb-S chalcogenide glass material and acousto-optic devices

Abstract

The present invention discloses an application of Ge-Sb-S chalcogenide glass material, wherein the Ge-Sb-S chalcogenide glass material is used as an acousto-optic medium in an acousto-optic device. The chemical composition formula of the chalcogenide glass material is Ge x Sb y S z . The chalcogenide glass material is non-toxic, has a short production cycle and low cost, and is easy to obtain high-quality, large-sized glass. Its physical properties almost meet the requirements of all high-quality acousto-optic materials, and its light transmission band can cover 0.8 to 10 μm, with a wide operating wavelength range. The acousto-optic device made with this chalcogenide glass material as the acousto-optic medium can achieve an acousto-optic diffraction efficiency of more than 70% when the driving power is as low as 0.2 W, meeting the requirement of achieving high acousto-optic diffraction efficiency under low power consumption. By adopting high-speed pulse modulation technology, the rise time and fall time of the optical pulse of the acousto-optic device were measured to be <55ns, the insertion loss was <2dB, and the extinction ratio was >65dB, which has important practical application value.

Description

Technical Field

[0001] The present invention belongs to the field of acousto-optic technology, and in particular relates to an application of a Ge-Sb-S chalcogenide glass material and an acousto-optic device. Background Art

[0002] Acousto-optics primarily studies the interaction between light and sound waves in a medium. When sound waves pass through a medium, the local compression and elongation they produce creates elastic strain, which leads to periodic density variations within the medium, forming a structure similar to a phase grating. When light waves pass through this medium disturbed by sound waves, diffraction occurs, a phenomenon known as the acousto-optic effect. Acousto-optic devices that utilize the acousto-optic effect to control and modulate laser beams have widespread applications in fiber-optic communications, laser technology, quantum mechanics, fiber-optic sensing, spectral imaging, and other fields. As one of the core components of an acousto-optic device, the performance of the acousto-optic dielectric material directly impacts the overall performance of the device.

[0003] TeO2 crystals have high visible light transparency and a large elastic-optical coefficient, making them the main acousto-optic medium in commercial acousto-optic devices. However, their acousto-optic figure of merit M2 along the

[001] direction in their common working mode is low, at only 34.5×10 -18 s 3 / g, it is difficult to achieve high acousto-optic diffraction efficiency at low driving power. Although the diffraction efficiency along the

[110] direction is as high as 793×10 -18 s 3 / g, but it has the disadvantages of small infrared transmittance, complex preparation process, high cost and difficulty in obtaining high-quality large single crystals, which makes it difficult to meet the development needs of high-performance infrared band acousto-optic devices.

[0004] Chalcogenide glass has the advantages of high acousto-optic figure of merit M2, wide infrared transmission range and easy large-scale manufacturing. Currently, the commercial acousto-optic chalcogenide glass material is mainly based on the Ge-As-Se system, with the representative composition being Ge 33 As 12 Se 55 , which has 246×10 -18 s 3 / g, achieving an acousto-optic diffraction efficiency of 67% at a driving power as low as 0.2 W. However, the presence of the toxic element As in this acousto-optic chalcogenide glass raises safety and environmental concerns during its preparation and use, and also has low short-wave near-infrared transmittance.

[0005] With the advancement of laser technology and lasers, acousto-optic devices are trending toward low power consumption, mid- and far-infrared operation, and low-cost, environmentally friendly designs. The properties of acousto-optic materials directly influence their performance and application scenarios. Therefore, the search for high-performance acousto-optic materials has become a research hotspot in the field of acousto-optic devices. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the shortcomings of the existing technology and provide an application of a Ge-Sb-S chalcogenide glass material and an acousto-optic device. The non-toxic chalcogenide glass material is used as an acousto-optic medium in the acousto-optic device, which can effectively improve the performance of the acousto-optic device. The acousto-optic device can achieve an acousto-optic diffraction efficiency of over 70% at a driving power as low as 0.2W, achieving high acousto-optic diffraction efficiency with low power consumption.

[0007] The technical solution adopted by the present invention to solve the above technical problems is: an application of a Ge-Sb-S chalcogenide glass material as an acousto-optic medium in an acousto-optic device, wherein the chemical composition formula of the Ge-Sb-S chalcogenide glass material is Ge x Sb y S z , wherein x, y and z represent the mole fractions of Ge, Sb and S respectively, 10≤x≤20, 20≤y≤30, 60≤z≤70. Preferably, x=15, y=24, z=61.

[0008] Ge x Sb y S z Chalcogenide glass materials are non-toxic, with short production cycles and low costs. They are also easy to obtain in high quality and large sizes. Their physical properties almost meet the requirements of all high-quality acousto-optic materials, and their light transmission band can cover 0.8 to 10 μm, with a wide operating wavelength range. x Sb y S z Chalcogenide glass materials, used as acousto-optic media in acousto-optic devices, can effectively improve their performance. The resulting acousto-optic devices can achieve an acousto-optic diffraction efficiency exceeding 70% at a drive power as low as 0.2W, achieving high acousto-optic diffraction efficiency with low power consumption. Using high-speed pulse modulation technology, the optical pulse rise and fall times of the fabricated acousto-optic devices were measured to be less than 55ns, with insertion loss less than 2dB and extinction ratio greater than 65dB, demonstrating their significant practical application value.

[0009] Preferably, the acousto-optic device is an acousto-optic modulator, an acousto-optic deflector or an acousto-optic filter.

[0010] In one embodiment, the AOM is a fiber-optic AOM.

[0011] Specifically, the fiber-type acousto-optic modulator is a fiber-coupled acousto-optic modulator.

[0012] An acousto-optic device includes an acousto-optic medium, a piezoelectric transducer, and an impedance matching network. The acousto-optic medium is a Ge-Sb-S chalcogenide glass material, and the chemical composition of the Ge-Sb-S chalcogenide glass material is Ge x Sb y S z , wherein x, y and z represent the mole fractions of Ge, Sb and S respectively, 10≤x≤20, 20≤y≤30, 60≤z≤70. Preferably, x=15, y=24, z=61.

[0013] Using Ge x Sb y S z The operating principle of an acousto-optic device fabricated using chalcogenide glass as the acousto-optic medium is as follows: First, an impedance matching network ensures that the RF power signal generated by the RF driver is efficiently transmitted to the piezoelectric transducer, preventing energy loss or reflection. The piezoelectric transducer then uses the piezoelectric effect to convert this RF power signal into an ultrasonic signal, generating acoustic waves. As these waves pass through the acousto-optic medium, they cause periodic changes in the density and refractive index of the medium, forming a dynamic grating. When a laser beam passes through the acousto-optic medium at a certain angle, Bragg diffraction occurs due to the interaction between the acoustic and optical elements.

[0014] Preferably, the piezoelectric transducer is a lithium niobate wafer.

[0015] Specifically, the optical pulse rise time and fall time of the acousto-optic device are respectively less than 55ns, the insertion loss is less than 2dB, and the extinction ratio is greater than 65dB; when the driving power is as low as 0.2W, the acousto-optic diffraction efficiency of the acousto-optic device is above 70%.

[0016] Specifically, the calculation formula for the acousto-optic diffraction efficiency is:

[0017]

[0018] Wherein, X(Δk) is an empirical parameter, Δk is the momentum mismatch coefficient, M2 is the acousto-optic figure of merit of the Ge-Sb-S chalcogenide glass material, λ is the operating wavelength of the acousto-optic device, L and H are the length and width of the acousto-optic interaction region, respectively, and P a is the ultrasonic power in the acousto-optic interaction region.

[0019] Compared with the prior art, the present invention has the following advantages: the Ge-Sb-S chalcogenide glass material of the present invention is used as an acousto-optic medium to produce high-performance acousto-optic devices. x Sb y S zChalcogenide glass materials are non-toxic, with short production cycles and low costs. They are also easy to obtain in high quality and large sizes. Their physical properties almost meet the requirements of all high-quality acousto-optic materials. x Sb y S z The light transmission band of chalcogenide glass material can cover 0.8~10μm, with a wide working wavelength range, and has important potential application value. x Sb y S z Using chalcogenide glass as the acousto-optic medium, the fabricated acousto-optic device achieves an acousto-optic diffraction efficiency exceeding 70% at a drive power as low as 0.2W, achieving high acousto-optic diffraction efficiency with low power consumption. Using high-speed pulse modulation technology, the fabricated acousto-optic device achieved optical pulse rise and fall times of less than 55ns, insertion loss less than 2dB, and extinction ratio greater than 65dB, demonstrating significant practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The infrared transmission spectra of the samples of Example 1 and Comparative Examples 1-2;

[0021] Figure 2 A top view of the structure of the fiber-coupled acousto-optic modulator made from the samples of Example 1 and Comparative Examples 1-2;

[0022] Figure 3 A front view of the structure of the fiber-coupled acousto-optic modulator made from the samples of Example 1 and Comparative Examples 1-2;

[0023] Figure 4 The diffraction principle diagram of the fiber-coupled acousto-optic modulator made from the samples of Example 1 and Comparative Examples 1-2. DETAILED DESCRIPTION

[0024] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments. All devices or components not limited in the present invention are conventional technical means in the art.

[0025] Select Ge 15 Sb 24 S 61 Chalcogenide glass material is used as Example 1, and commercialized acousto-optic medium material Ge 33 As 12 Se 55 The chalcogenide glass material is used as comparative example 1, and the commercially available acousto-optic medium material TeO2 crystal is used as comparative example 2.

[0026] The chalcogenide glass samples of Example 1 and Comparative Example 1 were prepared by a vacuum melting and quenching method. The specific preparation method can be divided into the following steps:

[0027] (1) According to the chemical composition formula of chalcogenide glass, accurately weigh each elemental raw material with a purity of 5N, mix the weighed raw materials evenly and place them in a quartz tube, and evacuate the quartz tube to a vacuum degree of 10 -3 After Pa, the quartz tube was sealed with hydrogen-oxygen flame;

[0028] (2) Place the sealed quartz tube in a rocking furnace and rock and melt it at 800-900°C for 10-12 hours. When the temperature in the furnace drops to 600-650°C, take the quartz tube out of the rocking furnace and quench and cool it with compressed air until the surface of the glass melt separates from the inner wall of the quartz tube.

[0029] (3) Place the quartz tube in a temperature set higher than the glass transition temperature T g Annealing is performed in an annealing furnace at a temperature of 5 to 20°C for 8 to 10 hours to release the internal stress of the glass. After annealing, the chalcogenide glass rod in the quartz tube is removed.

[0030] (4) Cut the chalcogenide glass rod into sheet samples and polish the glass surface using a polishing pad and polishing liquid to obtain sheet glass samples with two parallel sides and smooth surface.

[0031] The infrared transmission spectra of the samples of Example 1 and Comparative Examples 1-2 are shown in FIG. Figure 1 .from Figure 1 It can be seen that the Ge of Example 1 15 Sb 24 S 61 Chalcogenide glass materials have a wide range of permeable wavelengths, ranging from 0.8 to 10 μm. The permeable wavelength of the TeO2 crystal in Comparative Example 2 is relatively narrow, mainly concentrated in the range of 0.35 to 5 μm. Especially in the infrared region above 5 μm, its transmittance drops sharply, which limits its application in the mid- and far-infrared bands. In addition, the Ge in Example 1 15 Sb 24 S 61 The transmission wavelength range of the chalcogenide glass material is similar to that of Ge in Comparative Example 1. 33 As 12 Se 55 Chalcogenide glass materials are similar, but exhibit better performance in the near-infrared operating band and slightly improved overall transmittance.

[0032] In an acousto-optic device, the acousto-optic figure of merit M2 of the acousto-optic medium is an important parameter for characterizing the acousto-optic interaction. The acousto-optic figure of merit M2 of the samples of Example 1 and Comparative Example 1 is calculated using formula (1):

[0033]

[0034] The relevant parameters required to calculate the M2 value include refractive index n, photoelastic coefficient p 12 , density ρ and longitudinal wave speed υ L Among them, the refractive index n of the sample at a wavelength of 1550nm was measured using an infrared variable-angle spectroscopic ellipsometer, and the photoelastic coefficient p of the sample at a wavelength of 1550nm was measured using the Mach-Zehnder interferometry method and in accordance with the standard BS 7604-1-1992. 12 The density ρ of the sample was measured by the Archimedean drainage method, and the longitudinal wave velocity υ of the sample was measured by the pulse echo method in accordance with the GB / T 5266-2006 standard. L , the results are shown in Table 1.

[0035] Table 1: Acousto-optical properties of samples of Example 1 and Comparative Examples 1-2 at λ=1550nm

[0036]

[0037] As can be seen from Table 1, Ge 15 Sb 24 S 61 Chalcogenide glass materials have a high M2 value, which is 7 times that of TeO2 crystals and is comparable to Ge 33 As 12 S 55 The M2 value of chalcogenide glass materials is comparable, and they do not contain the toxic element As. They are safe and environmentally friendly and can be used as an acousto-optic medium in high-performance acousto-optic devices.

[0038] The samples of Example 1 and Comparative Examples 1-2 were used as acousto-optic media to make fiber-coupled acousto-optic modulators. Figure 2 , front view Figure 3 , see the diffraction principle diagram Figure 4 . Figures 2 to 4 In the figure, 1 is the acousto-optic medium, 2 is the piezoelectric transducer, 3 is the impedance matching network, 4 is the RF driver, 5 is the fiber collimator 1, 6 is the fiber collimator 2, 7 is the input fiber, and 8 is the output fiber. The impedance matching network 3 is used for the effective transmission of the RF power signal, ensuring that the impedance between the RF driver 4 and the piezoelectric transducer 2 is matched, thereby minimizing power reflection and loss. The piezoelectric transducer 2 uses a lithium niobate (LiNbO3) chip to convert the RF power signal into an acoustic wave of the same frequency, which propagates in the acousto-optic medium 1. The acousto-optic medium 1 is used to generate acousto-optic diffraction under the action of the acoustic wave and the incoming laser beam.

[0039] Here, the acousto-optic device is designed in Bragg diffraction mode, and the first-order diffraction light of the acousto-optic medium is used as the output light of the device. The formula for the first-order light diffraction efficiency of the Bragg diffraction mode is:

[0040]

[0041] In formula (2) It is established using the monochromatic plane wave acousto-optic interaction model under strict momentum matching conditions. The theoretical acousto-optic diffraction efficiency can reach 100%. Due to the certain divergence angle between the light field and the acoustic field in practice, momentum mismatch will inevitably occur to a certain extent, which needs to be corrected by the empirical parameter X(Δk). In formula (2), Δk is the momentum mismatch coefficient, M2 is the acousto-optic figure of merit of the acousto-optic medium, λ is the operating wavelength of the acousto-optic device, L and H are the length and width of the acousto-optic interaction region, respectively, and P a is the ultrasonic power in the acousto-optic interaction region.

[0042] In order to reduce insertion loss and energy loss, the width H of the acousto-optic interaction region needs to be selected to be larger than the waist diameter of the beam output by the fiber collimator to ensure that the light field inside the acousto-optic medium is completely surrounded by the sound field and to improve the light energy utilization rate. However, according to formula (2), H should be as small as possible to obtain a higher acousto-optic diffraction efficiency. Therefore, by reducing the beam diameter, H can be reduced and the light energy utilization rate can be guaranteed. Since the divergence angle of the light beam output by the fiber collimator is very small, coupling alignment is very difficult. At the same time, the separation angle between the diffracted light and the zero-order light itself increases the difficulty of coupling. Therefore, the ultra-small beam optical coupling technology is adopted to control the coupling loss between 0.3 and 0.8 dB according to different fiber collimator design parameters.

[0043] The fabricated fiber-coupled acousto-optic modulator operates as follows: First, an impedance matching network 3 ensures that the RF power signal generated by the RF driver 4 is efficiently transmitted to the piezoelectric transducer 2, preventing energy loss or reflection. The piezoelectric transducer 2 then uses the piezoelectric effect to convert this RF power signal into an ultrasonic signal, generating acoustic waves. These acoustic waves, when passing through the acousto-optic medium 1, cause periodic changes in the density and refractive index of the medium, forming a dynamic grating. When a laser beam passes through the acousto-optic medium 1 at a certain angle, Bragg diffraction occurs due to the interaction between the acoustic and optical elements.

[0044] The performance of three different acousto-optic devices made using the samples of Example 1 and Comparative Examples 1-2 as acousto-optic media was tested and compared at a wavelength of 1550 nm and a frequency of 80 MHz. The results are shown in Table 2.

[0045] Table 2: Performance comparison of three different acousto-optic devices at 1550nm and 80MHz

[0046]

[0047] From Table 2, we can see that Ge 15 Sb 24 S61 Acousto-optic devices using chalcogenide glass as the acousto-optic medium can achieve an acousto-optic diffraction efficiency of over 70% at a driving power as low as 0.2W. This driving power is 15 times lower than that of TeO2 crystals, meeting the requirement for achieving high acousto-optic diffraction efficiency at low power consumption. Furthermore, by adopting high-speed pulse modulation technology, the rise and fall times of the optical pulses of the fabricated acousto-optic device were measured to be less than 55ns, the insertion loss was less than 2dB, and the extinction ratio was greater than 65dB, demonstrating its important practical application value.

Claims

1. An application of a Ge-Sb-S chalcogenide glass material, characterized in that: The invention is applied to an acousto-optic device as an acousto-optic medium, and the acousto-optic device includes an acousto-optic medium, a piezoelectric transducer, an impedance matching network, an RF driver, a fiber collimator 1, a fiber collimator 2, an input fiber, and an output fiber: the impedance matching network is used for the effective transmission of the RF power signal, ensuring the impedance matching between the RF driver and the piezoelectric transducer, thereby minimizing the reflection and loss of power; the piezoelectric transducer is used to convert the RF power signal into an acoustic wave of the same frequency, which propagates in the acousto-optic medium; the acousto-optic medium is used to generate acousto-optic diffraction under the action of the acoustic wave and the incoming laser beam; the rise time and fall time of the optical pulse of the acousto-optic device are respectively less than 55ns, the insertion loss is less than 2dB, and the extinction ratio is greater than 65dB; when the driving power is as low as 0.2W, the acousto-optic diffraction efficiency of the acousto-optic device is more than 70%; the acousto-optic medium is a Ge-Sb-S chalcogenide glass material, and the chemical composition of the Ge-Sb-S chalcogenide glass material is Ge x Sb y S z , wherein x, y and z represent the mole fractions of Ge, Sb and S respectively, 10≤x≤20, 20≤y≤30, 60≤z≤70; the acousto-optic device is an acousto-optic modulator; The calculation formula of the acousto-optic diffraction efficiency is: Wherein, X(Δk) is an empirical parameter, Δk is the momentum mismatch coefficient, M2 is the acousto-optic figure of merit of the Ge-Sb-S chalcogenide glass material, λ is the operating wavelength of the acousto-optic device, L and H are the length and width of the acousto-optic interaction region, respectively, and P a is the ultrasonic power in the acousto-optic interaction region; The width H of the acousto-optic interaction region is larger than the waist diameter of the light beam output by the fiber collimator to ensure that the light field inside the acousto-optic medium is completely surrounded by the sound field, thereby improving the utilization rate of light energy. By reducing the width H by reducing the beam diameter, the utilization rate of light energy is guaranteed.

2. The use of the Ge-Sb-S chalcogenide glass material according to claim 1, characterized in that: x=15, y=24, z=61.

3. The use of the Ge-Sb-S chalcogenide glass material according to claim 1, characterized in that: The acousto-optic modulator is an optical fiber acousto-optic modulator.

4. The use of the Ge-Sb-S chalcogenide glass material according to claim 3, characterized in that: The fiber-type acousto-optic modulator is a fiber-coupled acousto-optic modulator.

5. The use of the Ge-Sb-S chalcogenide glass material according to claim 1, characterized in that: The piezoelectric transducer adopts a lithium niobate wafer.

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