Infinitely adjustable optical attenuator

Abstract

The application discloses a stepless adjustable optical attenuator, which comprises a packaging sleeve, two uniaxial crystals, a holder, a motor and a control system; the two uniaxial crystals are arranged in parallel on the inner sides of two ends of the packaging sleeve, one of the uniaxial crystals is a beam splitter for separating incident light beams into o light and e light, and the other uniaxial crystal is a beam combiner for combining the incident o light and e light; one uniaxial crystal is rotationally matched with the packaging sleeve through the holder; an arc-shaped light hole is formed in the holder; the motor is used for driving the holder and the uniaxial crystal on the holder to rotate; the motor is electrically connected with the control system, and the control system is used for inputting and displaying information. The o light and e light are decomposed from the uniaxial crystal, then the o light and e light are combined again, the shift of the optical axis of the uniaxial crystal is changed by the motor, the continuous control of the light attenuation amount is realized, and the intelligent control is realized through the control system, so that the super-continuous attenuation with high precision is realized.

Description

Technical Field

[0001] This invention relates to the field of passive optical devices, and more particularly to a steplessly adjustable optical attenuator. Background Technology

[0002] The continuous and rapid development of fiber optic communication technology has led to the maturation of fiber-to-the-home (FTTH) and the ongoing advancement of all-optical networks, representing a new generation of communication network development trends. In all-optical network communication, optical attenuators are one of the most important passive and indispensable basic components. Furthermore, optical attenuators are increasingly being used in optical sensing, signal processing, and other laser transmission optical systems, primarily serving to precisely control dynamic power levels, achieve dynamic gain flattening, and balance channel power gain in dense wavelength division multiplexing (DWDM) communication systems. Therefore, variable optical attenuators have broad application prospects in fiber optic communication, optical sensing, and laser transmission optical systems.

[0003] However, while current variable optical attenuators exist on various principles and in many types, including mechanical, magneto-optical, microelectromechanical system (MEMS), and liquid crystal (LCD) types, they still suffer from drawbacks such as complex structures and high manufacturing costs. Therefore, there is an urgent need to provide a steplessly adjustable optical attenuator to address the problems of existing technologies and meet the needs of rapid technological development in related fields. Summary of the Invention

[0004] The purpose of this invention is to provide a steplessly adjustable optical attenuator to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides a steplessly adjustable optical attenuator, comprising:

[0006] Encapsulation sleeve;

[0007] Two uniaxial crystals are arranged in parallel on the inner sides of both ends of the encapsulation sleeve. One uniaxial crystal is a beam splitter that separates the incident beam into o-beams and e-beams, and the other uniaxial crystal is a beam combiner that combines the incident o-beams and e-beams. In the initial state, the optical axis angle between the beam splitter and the beam combiner is 90°.

[0008] A clamp is rotatably connected to one end of the encapsulation sleeve, and a single-axis crystal is rotatably engaged with the encapsulation sleeve through the clamp; the clamp has an arc-shaped light-transmitting hole, and the center of the arc-shaped light-transmitting hole is coaxial with the central axis of the encapsulation sleeve.

[0009] An electric motor is used to drive the clamp and the uniaxial crystal on the clamp to rotate;

[0010] The control system is electrically connected to the motor and is used for information input and display.

[0011] Preferably, the uniaxial crystal has a cuboid structure, and the two uniaxial crystals have the same thickness.

[0012] Preferably, the four light-transmitting surfaces of the two uniaxial crystals are arranged in parallel, and the surface finish of the light-transmitting surfaces is not lower than grade 12.

[0013] Preferably, the light-transmitting surface is coated with a high-transmittance thin film.

[0014] Preferably, a circular guide groove is formed on the inner wall of the encapsulation sleeve, and the clamp is slidably installed in the circular guide groove.

[0015] Preferably, the outer side of the clamp is provided with a protrusion, and the clamp is slidably mounted in the circular guide groove through the protrusion.

[0016] Preferably, the arc length of the arc-shaped light-transmitting hole is a quarter circle.

[0017] Preferably, a fixing hole is provided in the middle of the clamp, and the clamp is fixed to the output shaft of the motor through the fixing hole.

[0018] Preferably, the motor is a stepper motor.

[0019] Preferably, the control system includes a processing unit, a display screen, a reset button, and a keyboard; the motor, the display screen, the reset button, and the keyboard are all electrically connected to the processing unit; the keyboard is used for information input, the reset button is used to rotate the motor to its initial position, the display screen is used for information display, and the processing unit is used to convert the input information into the rotation angle of the motor.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects:

[0021] The stepless adjustable optical attenuator provided by this invention utilizes a uniaxial crystal to decompose the light into o-rays and e-rays, and then combines them. Furthermore, it uses a motor to change the offset of the optical axis of the uniaxial crystal to achieve continuous control of the optical attenuation. At the same time, it achieves high-precision ultra-continuous attenuation through intelligent control of the control system. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the stepless adjustable optical attenuator of the present invention;

[0024] Figure 2 This is a front view schematic diagram of the clamp of the present invention;

[0025] In the diagram: 1. Encapsulation sleeve; 2. Bundle splitter; 3. Bundle combiner; 4. Clamp; 5. Stepper motor; 6. Control system; 7. Arc-shaped light-transmitting hole; 8. Circular guide groove; 9. Fixing hole. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The described embodiments are merely some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] like Figures 1 to 2 As shown, the present invention provides a steplessly adjustable optical attenuator, comprising:

[0028] Encapsulation sleeve 1;

[0029] Two uniaxial crystals are arranged in parallel on the inner sides of both ends of the encapsulation sleeve 1. One uniaxial crystal is a beam splitter 2 that separates the incident beam into o-beams and e-beams, and the other uniaxial crystal is a beam combiner 3 that combines the incident o-beams and e-beams. In the initial state, the optical axis angle between the beam splitter 2 and the beam combiner 3 is 90°.

[0030] The clamp 4 is rotatably connected to one end of the encapsulation sleeve 1. A uniaxial crystal is rotatably engaged with the encapsulation sleeve 1 through the clamp 4. The clamp 4 has an arc-shaped light-transmitting hole 7, and the center of the arc-shaped light-transmitting hole 7 is coaxial with the central axis of the encapsulation sleeve 1.

[0031] The motor is used to drive the gripper 4 and the uniaxial crystal on the gripper 4 to rotate;

[0032] Control system 6, the motor is electrically connected to control system 6, control system 6 is used for information input and display.

[0033] This invention utilizes a single-axis crystal to decompose a light beam into o-beams and e-beams, and then uses the same single-axis crystal to combine them. Furthermore, it uses a motor to change the offset of the optical axis of the single-axis crystal, thereby achieving continuous control of the light attenuation. Simultaneously, it uses a control system 6 for intelligent control, thereby achieving high-precision supercontinuous attenuation.

[0034] The scheme was further optimized so that the uniaxial crystal has a cuboid structure and the two uniaxial crystals have the same thickness.

[0035] The design was further optimized so that the four light-transmitting surfaces of the two uniaxial crystals are arranged in parallel, and the surface finish of the light-transmitting surfaces is no less than grade 12.

[0036] The design was further optimized by coating the light-transmitting surface with a high-transmittance thin film.

[0037] To further optimize the design, a circular guide groove 8 is provided on the inner wall of the encapsulation sleeve 1, and the clamp 4 is slidably installed in the circular guide groove 8.

[0038] To further optimize the design, a protrusion is provided on the outer side of the clamp 4, and the clamp 4 is slidably installed in the circular guide groove 8 through the protrusion.

[0039] The design was further optimized so that the arc length of the arc-shaped light-transmitting hole 7 is one-quarter of a circle.

[0040] To further optimize the design, a fixing hole 9 is opened in the middle of the clamp 4, and the clamp 4 is fixed to the output shaft of the motor through the fixing hole 9.

[0041] The design was further optimized, and the motor was changed to a stepper motor 5.

[0042] The scheme is further optimized. The control system 6 includes a processing unit, a display screen, a reset button, and a keyboard. The motor, display screen, reset button, and keyboard are all electrically connected to the processing unit. The keyboard is used for information input, the reset button is used to rotate the motor to the initial position, the display screen is used for information display, and the processing unit is used to convert the input information into the rotation angle of the motor.

[0043] The stepless adjustable optical attenuator provided by this invention operates on the following principle:

[0044] The holder 4 can be on the beam splitter 2 or the beam combiner 3. If it is on the beam combiner 3, the incident beam enters through the arc-shaped light-passing hole 7 on the holder 4. If it is on the beam combiner 3, then... Figure 1 As shown, the beam combiner 3 combines the o-beam and e-beam and outputs them from the arc-shaped light-transmitting hole 7.

[0045] The incident beam is perpendicularly incident on the first light-transmitting surface of the beam splitter 2. The o-beam exits perpendicularly and then is perpendicularly incident on the second light-transmitting surface and exits perpendicularly thereafter. The e-beam is downwardly polarized and then incident on the second light-transmitting surface of the beam splitter 2 at a certain incident angle and exits perpendicularly thereafter. The o-beam and e-beam exiting perpendicularly to the second light-transmitting surface of the beam splitter 2 are transmitted forward and incident perpendicularly on the first light-transmitting surface of the beam combiner 3. After entering the uniaxial crystal of the beam combiner 3, the o-beam becomes the e-beam, deflects downward, and then incident on the second light-transmitting surface of the beam combiner 3 at a certain incident angle. The e-beam becomes the o-beam, exits perpendicularly to the first light-transmitting surface of the beam combiner 3, and then incident perpendicularly on the second light-transmitting surface of the beam combiner 3. At the incident point on the second light-transmitting surface of the beam combiner 3, the o-beam and e-beam are bundled together. The light after the o-beam and e-beam are bundled together exits perpendicularly to the second light-transmitting surface of the beam combiner 3 and finally exits from the arc-shaped light-transmitting hole 7 of the holder 4.

[0046] During the process, beam splitter 2 remains stationary, maintaining its optical axis direction. However, beam splitter 2 can rotate, thus changing its optical axis direction. Beam splitter 2 rotates in a plane perpendicular to the central axis of the encapsulation sleeve 1. When the angle between the optical axes of beam splitter 2 and beam combiner 3 deviates from 90°, the power of the outgoing beam will decrease relative to the incident beam. The corresponding power loss can be derived from the Jones matrix using the loss formula:

[0047] IL = -10C(λ)log[cos 2 (Δθ)] dB

[0048] Where IL is the attenuation amount; Δθ is the amount by which the optical axis angle between the beam combiner 3 and the beam splitter 2 deviates from 90°; C(λ) is a wavelength-related constant and is related to the transmittance coefficient of the uniaxial crystal for different wavelengths.

[0049] Therefore, the output optical power relative to the input optical power can be continuously varied by rotating one of the uniaxial crystals to change the angle between the optical axes, thus achieving the purpose of stepless tuning of the attenuation.

[0050] The rotation angle of the single-axis crystal, whether it is reset, and other actions are all completed by the control system 6. The control system 6 consists of a processing unit, a display screen, a reset button, and a keyboard. It can input the wavelength and the desired attenuation. The display screen will also display the input information, the final attenuation, and the corresponding rotation angle value. The processing unit converts the input light wavelength and the desired attenuation into the angle that the motor needs to rotate, and then drives the stepper motor 5 to rotate the single-axis crystal by the corresponding angle. When the optical attenuator stops working, pressing the reset button will cause the stepper motor 5 to rotate back to the initial position, so that the optical axis angle between the beam combiner 3 and the beam splitter 2 is 90°. At this time, the rotation angle value of the stepper motor 5 on the display screen will be 0°.

[0051] The continuously adjustable optical attenuator provided by this invention utilizes the characteristics of two uniaxial crystals and the refraction of o-ray and e-ray by the optical axes of the uniaxial crystals. The two uniaxial crystals are designed to be perpendicular to each other, making them beam splitter 2 and beam combiner 3 for o-ray and e-ray respectively. It cleverly utilizes the fact that when the angle between the optical axis of beam combiner 3 and the optical axis of beam splitter 2 deviates by 90°, the final output optical signal will experience corresponding loss; the greater the deviation, the greater the loss, i.e., the corresponding attenuation of the optical signal. The greater the deviation of the perpendicular optical axes, the greater the attenuation. The rotation of the uniaxial crystal is precisely driven by a stepper motor 5 controlled by a control system 6. The processing unit of the control system 6 converts the input light wavelength and the desired attenuation into the required rotation angle of the stepper motor 5, thereby driving the stepper motor 5 to rotate the uniaxial crystal by the corresponding angle, based on the optical axis 90°. The attenuation is approximately 0.003 dB when the angle deviation is 1°. Therefore, very precise attenuation can be easily achieved by driving the single-axis crystal rotation with stepper motor 5, without requiring a motor with very fine stepping. Furthermore, the rotation angle is not constrained by other factors, allowing for a wide range of attenuation. The control system 6 also displays the execution results on the screen. Pressing the reset button when the optical attenuator exits operation, causing stepper motor 5 to return to its initial position, will also display corresponding information. The input information given to the control system 6 is the wavelength, so the rotation angle calculated by the control system 6 includes the wavelength's influence. The final attenuation amount already takes the wavelength into account, therefore the attenuation amount is essentially independent of the wavelength. Additionally, the processing of the optical transmission surface of the single-axis crystal can be easily achieved using optical glass processing methods. Therefore, this invention features very high precision optical attenuation, stepless variable super-continuous attenuation, a large dynamic range, and no wavelength-dependent loss problems. It is highly intelligent, reliable, stable, and easy to implement.

[0052] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A continuously adjustable optical attenuator, characterized by, The utility model relates to a kind of optical polarization modulation device, including: Encapsulation sleeve (1); Two single-axis crystals, parallelly arranged in the inside of two ends of the encapsulation sleeve (1), one single-axis crystal is the beam splitter (2) of separating o light and e light from incident light beam, another single-axis crystal is the combiner (3) of the incident o light and e light beam combination;Initial state, the optical axis angle of the beam splitter (2) and the combiner (3) is 90 °; Holder (4), the holder (4) is rotatably connected in one end of the encapsulation sleeve (1), a single-axis crystal is rotatably matched with the encapsulation sleeve (1) by the holder (4);Circular arc light hole (7) is set on the holder (4), and the center of the circular arc light hole (7) is coaxially arranged with the central axis of the encapsulation sleeve (1); Motor, the motor is used to drive the holder (4) and the single-axis crystal on the holder (4) to rotate; Control system (6), the motor is electrically connected with the control system (6), and the control system (6) is used for information input and display.

2. The continuously adjustable optical attenuator of claim 1, wherein, The single-axis crystal is cuboid structure, and the thickness of two single-axis crystals is same.

3. The continuously adjustable optical attenuator of claim 1, wherein, Four light transmission surfaces of two single-axis crystals are parallelly arranged, and the smoothness of light transmission surface is not less than 12 levels.

4. The continuously adjustable optical attenuator of claim 3, wherein, The light transmission surface is coated with high-transmittance film.

5. The continuously adjustable optical attenuator of claim 1, wherein, Circular guide groove (8) is set on the inner wall of the encapsulation sleeve (1), and the holder (4) is slidably installed in the circular guide groove (8).

6. The continuously adjustable optical attenuator of claim 5, wherein, The outer side of the holder (4) is provided with a protrusion, and the holder (4) is slidably installed in the circular guide groove (8) through the protrusion.

7. The continuously adjustable optical attenuator of claim 1, wherein, The arc length of the circular arc light hole (7) is one quarter of a circle.

8. The continuously adjustable optical attenuator of claim 1, wherein, Fixed hole (9) is set in the middle of the holder (4), and the holder (4) is fixed with the output shaft of the motor through the fixed hole (9).

9. The continuously adjustable optical attenuator of claim 8, wherein, The motor is a stepper motor (5).

10. The continuously adjustable optical attenuator of claim 1, wherein, The control system (6) includes processing unit, display screen, reset key and keyboard;The motor, the display screen, the reset key and the keyboard are electrically connected with the processing unit;The keyboard is used for information input, the reset key is used to make motor rotate to initial position, the display screen is used for information display, and the processing unit is used to convert input information into the rotation angle of motor.

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