Pre-compensation of interference in pockels cells

Abstract

To enable secondary electrical modulation for acoustic compensation of an electro-optic modulator (EOM) for use in the Long-Wave Infrared (LWIR) spectrum and Mid-Wave Infrared (MWIR) spectrum.SOLUTION: A system and method is disclosed, for providing secondary electrical modulation for acoustic compensation of an electro-optic modulator (EOM) for use in the Long-Wave Infrared (LWIR) spectrum and Mid-Wave Infrared (MWIR) spectrum.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and benefit of U.S. Provisional Patent Application No. 63 / 552,511, filed February 12, 2024, entitled "SECONDARY ELECTRICAL MODULATION FOR ACOUSTIC COMPENSATION OF EOM FOR USE IN LWIR AND MWIR SPECTRUM," which is hereby incorporated by reference in its entirety. [Background technology]

[0002]

[0002] The limitations and drawbacks of conventional electro-optic modulators (EOMs) will become apparent to those skilled in the art upon comparing such approaches with certain aspects of the present method and system described in the remainder of this disclosure with reference to the drawings. Summary of the Invention

[0003]

[0003] The system and method provide secondary electrical modulation for acoustic compensation of electro-optic modulators (EOMs) for use in the long-wave infrared (LWIR) and mid-wave infrared (MWIR) spectrums substantially as shown in and / or described in connection with at least one of the figures and more fully as set forth in the claims. [Brief explanation of the drawings]

[0004] [Figure 1] FIG. 4 illustrates an example EOM using a square wave voltage input, according to various example embodiments of the present disclosure. [Figure 2]

[0005] FIG. 1 illustrates an example EOM that uses a voltage input that includes a secondary electrical signal for pre-compensation of acoustic interference generated by the EOM, according to various example embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0005]

[0007] The following description provides various examples of systems and methods for reducing acoustic interference by using electrical signal pre-compensation. Such examples are non-limiting, and the scope of the appended claims should not be limited to the particular examples disclosed. In the following description, the terms "example" and "for example" are non-limiting.

[0006]

[0008] The figures show general schemes of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the present disclosure. Additionally, elements in the depicted figures are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of the examples discussed in this disclosure. The same reference numbers in different figures represent the same elements.

[0007]

[0009] The term "or" means any one or more of the items in the list connected by "or." As an example, "x or y" means any element of the three element set {(x),(y),(x,y)}. As another example, "x, y, or z" means any element of the seven element set {(x),(y),(z),(x,y),(x,z),(y,z),(x,y,z)}.

[0008]

[0010] The terms "comprises," "comprising," "includes," and / or "including" are "open-ended" terms that specify the presence of stated features but do not exclude the presence or addition of one or more other features.

[0009]

[0011] Terms such as "first," "second," and the like may be used herein to describe various elements, but these elements should not be limited by these terms. These terms are used only to distinguish one element from another. Thus, for example, a first element discussed in this disclosure could be referred to as a second element without departing from the teachings of the disclosure.

[0010]

[0012] Unless otherwise specified, the term "coupled" may be used to describe two elements that are in direct contact with each other or two elements that are indirectly connected by one or more other elements. For example, if element A is coupled to element B, element A may be in direct contact with element B or indirectly connected to element B by an intervening element C. Similarly, the terms "over" or "on" may be used to describe two elements that are in direct contact with each other or two elements that are indirectly connected by one or more other elements.

[0011]

[0013] Light is a fundamental phenomenon with diverse properties and applications that span the electromagnetic spectrum, from radio waves to gamma rays. While the human eye perceives only the visible spectrum, light extends beyond this range and includes longer wavelengths, such as infrared, and shorter wavelengths, such as ultraviolet and X-rays. These wavelength differences correspond to changes in energy, provide unique interactions with materials, and enable specialized technologies. For example, long-wave infrared (LWIR) light is characterized by lower energy and longer wavelengths compared to visible light and plays an important role in areas such as imaging, industrial processing, and advanced optics.

[0012]

[0014] An important attribute of light is its polarization, the orientation of its electric field in space. Polarization can appear as linear, circular, or elliptical, depending on the light wave's interaction with materials or filters. This property is particularly important when dealing with coherent light sources such as lasers, which propagate in a fixed direction and exhibit consistent wavelengths and polarizations. Being able to manipulate polarization can enable precise control over light for applications such as optical switching and modulation.

[0013]

[0015] The electro-optic effect, specifically the Pockels effect, is central to the operation of electro-optic modulators (EOMs), which enable dynamic control of light polarization. This effect occurs in certain non-centrosymmetric crystals, where an applied electric field causes a change in the refractive index, altering the polarization state of the transmitted light. Materials such as cadmium telluride (CdTe), gallium arsenide (GaAs), zinc selenide (ZnSe), zinc sulfide (ZnS), cadmium zinc telluride (CdZnTe or CZT), and boron arsenides (BAs) are among the few materials capable of supporting this effect in the LWIR and mid-wave infrared (MWIR) spectrum due to their unique optical and structural properties.

[0014]

[0016] Pockels cells, the key component of EOMs, utilize these electro-optic materials to modulate light at high speeds without moving parts. By applying a voltage and / or electric field across the crystal, the birefringence of the material can be controlled, which can enable phase modulation of a laser beam with nanosecond precision. This capability is important in advanced applications such as extreme ultraviolet (EUV) lithography, where precise timing and modulation of light is essential to producing cutting-edge microchips.

[0015]

[0017] This disclosure relates to systems and methods for mitigating acoustic interference in electro-optic modulators (EOMs), specifically Pockels cells, by utilizing active acoustic compensation techniques. Acoustic interference arising from the piezoelectric effect inherent in electro-optic crystals can degrade the modulation efficiency and performance of Pockels cells. The disclosed solution addresses these challenges by generating a secondary compensation signal to counteract the undesired acoustic effects, resulting in improved system performance.

[0016]

[0018] Pockels cells, which operate on the linear electro-optic effect, modulate optical transmittance by changing the birefringence properties of a crystal in response to an electric field. Materials that exhibit the linear electro-optic effect inherently also exhibit piezoelectric properties. When a voltage is applied, the piezoelectric effect induces mechanical stress in the crystal, creating acoustic waves that propagate through the assembly. As a result, these acoustic waves generate stress-induced birefringence effects, which can reduce the modulation efficiency (e.g., extinction coefficient) of the EOM.

[0017]

[0019] For example, when modulating a laser beam, the crystal may generate acoustic waves with each pulse, causing the assembly to resonate at specific frequencies. These resonances can cause acoustic ringing that interferes with the desired modulation behavior. At certain frequencies (e.g., 41 kHz), the interference can be significant, while at other frequencies (e.g., 57 kHz), the interference may be negligible. This variability can complicate reliable modulation over a wide frequency range.

[0018]

[0020] The disclosed systems and methods utilize active compensation to reduce or eliminate the effects of acoustic interference in EOMs. This component can effectively attenuate or cancel acoustic waves generated by the primary electro-optic crystal, achieving a net reduction in interference.

[0019]

[0021] A complex input waveform can be generated by superimposing a secondary electrical signal on the primary modulation signal. This compensation signal is configured to produce self-canceling acoustic and electrical effects, reducing interference across the device.

[0020]

[0022] 1 illustrates an example EOM 101 that uses a square wave voltage input 103, according to various example embodiments of the present disclosure. Light waves 105 that are undesirably modulated by acoustic waves caused by the piezoelectric effect can add undesirable artifacts 107 that can hinder the performance of the EOM.

[0021]

[0023] 2 illustrates an example EOM 101 that uses a voltage input including a secondary electrical signal 201 for compensation of acoustic interference generated by the EOM 101, according to various example embodiments of the present disclosure. Compensation signal 201 is added to input waveform 103 to compensate for undesired artifacts 107 (in FIG. 1 ) and reduce acoustic interference, thereby generating a more complete / compensated optical output 205.

[0022]

[0024] Piezoelectric components can generate opposing acoustic waves that mitigate the interference.

[0025] The disclosed system can improve the extinction coefficient by reducing stress-induced birefringence caused by acoustic waves. By dynamically generating the compensation signal, the disclosed system avoids dependency on a specific pulse frequency or amplitude and can address interference over a wide operating range.

[0023]

[0026] Unlike conventional systems, the disclosed solution effectively handles high power levels while maintaining modulation clarity. The piezoelectric compensation component can comprise the same material as the electro-optic crystal to ensure perfect acoustic matching. For example, a gallium arsenide layer may be bonded to the crystal in a specific crystallographic orientation for optimal performance.

[0024]

[0027] To achieve compensation, the system analyzes the behavior of the EOM at various frequencies using sensitive electrical equipment, such as an oscilloscope. Compensation waveforms may be designed according to this analysis and implemented using one of two approaches.

[0025]

[0028] In the first approach (ie, carrier correction), a secondary electrical signal can be superimposed on the primary input current signal to create an overall compensation effect.

[0029] In the second approach (ie, circuit-based compensation), a circuit with impedance, resistance, and / or capacitance can be used to generate a compensation waveform by mimicking the acoustic behavior of the device.

[0026]

[0030] The secondary signal may be driven by the same pulse system as the primary modulation, or by a separate circuit. Synchronization can be achieved by designing the secondary waveform to match the acoustic characteristics of the EOM assembly. The secondary waveform may be optimized for high-frequency laser (e.g., ultraviolet or x-ray) operation.

[0027]

[0031] Mechanical aspects of the system, such as electrode configuration, may be fine-tuned to dynamically optimize compensation. For example, the system may be configured to analyze acoustic waves in real time to adjust the secondary waveform. The secondary waveform may also be generated according to an algorithm for adaptive signal generation. The secondary waveform may also be continuously adjusted according to a feedback signal. The compensation waveform may also be stored as a programmable profile.

[0028]

[0032] The disclosed systems and methods may be applicable to long-wavelength infrared electro-optic modulators, high-power optical systems, and other devices requiring precision optical modulation, which may outperform conventional solutions in terms of efficiency, durability, and acoustic attenuation while maintaining operational flexibility.

[0029]

[0033] In the disclosed systems and methods, the secondary waveform may be derived from the primary waveform using a transformation circuit. Additionally, the primary and secondary waveforms may be generated from a common power source.

[0030]

[0034] While the present method and / or system has been described with reference to specific embodiments, it will be understood by those skilled in the art that various modifications may be made and equivalents may be substituted without departing from the scope of the present method and / or system. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from its scope. Therefore, it is not intended that the present method and / or system be limited to the particular embodiments disclosed, but rather that the present method and / or system will include all embodiments falling within the scope of the appended claims.

Claims

1. a primary generator configured to generate a primary waveform; a secondary generator configured to generate a secondary waveform as a compensation waveform in accordance with the primary waveform; an electro-optic crystal operably coupled to the primary generator and the secondary generator; A system including:

2. 10. The system of claim 1, wherein the secondary waveform is derived from the primary waveform using a transformation circuit.

3. The system of claim 1 , wherein the secondary waveform is configured to compensate for thermal stresses in the electro-optic crystal.

4. 10. The system of claim 1, wherein the secondary waveforms are independently modulated for specific sound effects.

5. 10. The system of claim 1, wherein the secondary waveform is generated according to an algorithm for adaptive signal generation.

6. 10. The system of claim 1, wherein the secondary waveform is optimized for high frequency laser operation.

7. 10. The system of claim 1, wherein the secondary waveform is continuously adjusted according to a feedback signal.

8. 10. The system of claim 1, wherein the primary waveform and the secondary waveform are generated from a common power source.

9. 10. The system of claim 1, wherein the compensation waveform is stored as a programmable profile.

10. 10. The system of claim 1 configured to analyze acoustic waves in real time to adjust the secondary waveform.

11. modulating a Pockels cell via a primary waveform and a secondary waveform; reducing acoustic interference by adapting the secondary waveform according to optical power; A method comprising:

12. 12. The method of claim 11, comprising deriving the secondary waveform according to the primary waveform via a transformation circuit.

13. 12. The method of claim 11, wherein the secondary waveform is configured to compensate for thermal stresses in the Pockels cell.

14. 12. The method of claim 11, wherein the secondary waveforms are independently modulated for specific sound effects.

15. 12. The method of claim 11, wherein the secondary waveform is generated according to an algorithm for adaptive signal generation.

16. 12. The method of claim 11, wherein the secondary waveform is optimized for high frequency laser operation.

17. 12. The method of claim 11, wherein the secondary waveform is continuously adjusted according to a feedback signal.

18. 12. The method of claim 11, wherein the primary waveform and the secondary waveform are generated from a common power source.

19. 12. The method of claim 11, wherein the secondary waveform is stored as a programmable profile.

20. The method of claim 11 , wherein the acoustic analysis is performed in real time.

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