Mechanical adjustable optical attenuator attenuation piece initial position positioning method

Abstract

The present application belongs to the technical field of tunable optical attenuator attenuating sheet, and particularly relates to a mechanical tunable optical attenuator attenuating sheet initial position positioning method, which realizes initial positioning of the attenuating sheet by using an attenuating sheet initial position positioning system, and the attenuating sheet initial position positioning system comprises a motor, a light blocking sheet, a photo-coupler, an encoder disk and an encoding module; the method is to realize two-stage positioning by making the rotational speeds of the two ends of the double-end output shaft motor inconsistent, the first stage adopts a motor broken step rotation mode, the photo-coupler is used to coarsely position the attenuating sheet by using a level conversion signal, and the second stage positioning system uses a CHI signal of the encoding system to realize accurate positioning of the initial position of the attenuating sheet. The present application uses a two-stage positioning system, the response time of the encoding system can reach ns level, so that the positioning accuracy of the initial position of the attenuating sheet is further improved, and the attenuation accuracy and repeatability of the tunable optical attenuator are ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of attenuation sheets of adjustable optical attenuators, and in particular relates to an initial position positioning method of an attenuation sheet of a mechanical adjustable optical attenuator. Background Art

[0002] A circular attenuator is the core component of a mechanical variable optical attenuator. The initial position of the attenuator, defined as a certain location within the blank area of ​​the coating, serves as the absolute zero point for encoding the attenuator's arc position. This means that encoding for any arc position on the attenuator uses this initial position as the absolute zero point. The accuracy of the attenuator's initial position directly impacts key technical specifications of the variable optical attenuator, including attenuation accuracy, linearity, and insertion loss.

[0003] At present, the method for locating the initial position of the attenuator of a mechanical variable optical attenuator is to use the level conversion signal generated by the optical coupler device to determine the initial position of the attenuator. Figure 1 As shown, an attenuator and light block are mounted on the motor shaft, ensuring that the attenuation blanking area of ​​the attenuator and the light block are relatively fixed. When the light block enters the groove of the optocoupler, the blanking area of ​​the attenuator lies precisely within the spatial light path formed by the optical input collimator and the optical output collimator. When the adjustable optical attenuator is activated, the motor rotates the attenuator and light block in a specific direction. When the light block enters the groove of the optocoupler, the optocoupler generates a level conversion signal, and the blanking area of ​​the attenuator falls precisely within the spatial light path, minimizing the insertion loss of the adjustable optical attenuator. At the moment of the optocoupler level conversion, the motor stops, and this point is used as the initial position of the attenuator.

[0004] Since the response time of the optocoupler is in the μs order, the response time is relatively long, and the motor rotation has a certain inertia. This results in the motor not being able to stop in time when the light shield enters the groove of the optocoupler. In addition, each time the adjustable optical attenuator is restarted and powered on, the starting position of the light shield is inconsistent, which leads to a certain difference in the initial position of the attenuator after each instrument startup. As a result, the key technical indicators of the instrument, such as attenuation accuracy, linearity, and insertion loss, are inaccurate and have poor consistency. Summary of the Invention

[0005] In response to the various shortcomings of the existing technology, the inventors have researched and designed a method for initial positioning of the attenuation plate of a mechanical adjustable optical attenuator through long-term practice. The method uses a double-end output shaft motor with a reduction ratio, and utilizes an optical coupler device and an encoding system to form a two-stage positioning system. Each time the adjustable optical attenuator is turned on, the initial position of the attenuation plate can be kept as unchanged as possible, thereby improving the accuracy of key technical indicators of the instrument such as attenuation accuracy, linearity, and insertion loss.

[0006] The present invention provides a method for locating the initial position of an attenuation plate of a mechanically adjustable optical attenuator, which realizes the initial positioning of the attenuation plate by using an attenuation plate initial position positioning system. The attenuation plate initial position positioning system includes a motor, a light shield, an optical coupling device, an encoding disk, and an encoding module, and the encoding disk and the encoding module constitute an encoding system. The motor is a double-end output shaft motor with a reduction ratio of 1:N. The attenuation plate and the light shield are installed on the slow-end output shaft of the motor, the optical coupling device is arranged below the light shield, the encoding disk is installed on the fast-end output shaft of the motor, and the encoding module is arranged above the encoding disk. The specific method is as follows:

[0007] Step 1: Power on the variable optical attenuator.

[0008] Step 2: When the motor rotates forward at a constant speed and drives the light shield to rotate into the groove of the optocoupler, the optocoupler generates a level conversion signal, and the main control CPU controls the motor to stop rotating.

[0009] Step 3: The counter on the encoding module starts and begins counting. At the same time, the motor starts to rotate in the reverse direction at a uniform speed. When the light blocking plate rotates out of the groove of the optocoupler, the optocoupler generates a level conversion signal again. The motor continues to rotate for any time of 100ms, 110ms or 120ms. Then, the main control CPU controls the motor to stop rotating. At this time, the counter has counted n encoding pulses.

[0010] Step 4: The motor rotates forward according to m encoded pulse steps. When the light shield enters the groove of the optocoupler device for the second time, the optocoupler device generates a level conversion signal for the third time, and the main control CPU controls the motor to stop rotating.

[0011] Step 5: The motor rotates in the reverse direction according to m encoding pulse steps. When the light shield rotates out of the groove of the optocoupler for the second time, the optocoupler generates a level conversion signal for the fourth time. The main control CPU controls the motor to stop rotating and the encoding count is reset.

[0012] Step 6: The motor steps in steps of n encoding pulses and continues to rotate in the reverse direction until the encoding module detects the CHI signal of the encoding disk. The motor stops rotating and reads the number of pulses Pc in the encoding module counter. The number of pulses Pc is the number of pulses of the CHI signal of the encoding disk from the detection point of the encoding module.

[0013] Step 7: By formula Calculate the arc distance of the CHI signal of the encoder disk from the detection point on the encoding module , where P is the total number of pulses in one cycle of the encoder disk; Whether the requirement of 120° to 240° is met, if so, the point is the initial position of the attenuation plate, if not, the motor rotates forward to the next circle, and steps 2 to 7 are repeated.

[0014] Furthermore, the reduction ratio of the motor is any one of 1:76, 1:141, 1:262, 1:485, 1:900 and 1:1670.

[0015] Furthermore, when the light blocking sheet enters the groove of the optical coupling device, the attenuation blank area of ​​the attenuation sheet is exactly located in the spatial light path formed by the light input collimator and the light output collimator.

[0016] Furthermore, every time the attenuation plate and the light-blocking plate rotate one circle, the arc position of the CHI signal on the encoding disk from the detection point on the encoding module forms an angle of 18.4°~19.4° with that of the previous circle; after the attenuation plate rotates N circles, the arc position of the CHI signal on the encoding disk from the detection point on the encoding module returns to the initial arc, and the error with the initial arc is no more than 5°.

[0017] Furthermore, m<n, and m is any natural number between 30 and 50.

[0018] The beneficial effects of the present invention are:

[0019] By adopting a two-stage positioning system, the first-stage positioning system uses the motor to rotate in small steps and utilizes the level conversion signal of the optocoupler device to roughly position the attenuator, reducing the inertial effect of the motor's uniform rotation and improving positioning accuracy. The second-stage positioning system uses the CHI signal of the encoding system to accurately locate the initial position of the attenuator. Since the response time of the encoding system can reach the nanosecond level, the initial position positioning accuracy of the attenuator is further improved, ensuring the attenuation accuracy and repeatability indicators of the adjustable optical attenuator, and expanding its application range. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural diagram of the positioning system in the prior art

[0021] Figure 2 Schematic diagram of the positioning system structure of the present invention.

[0022] Figure 3 It is a flowchart of the positioning method of the present invention.

[0023] In the attached figure: 1-attenuation plate, 2-light blocking plate, 3-optical coupler, 4-encoding disk, 5-encoding module, 6-motor. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below in conjunction with the accompanying drawings and implementation examples. These implementation examples are described in sufficient detail to enable those skilled in the art to understand and practice the present invention. Without departing from the spirit and scope of the present invention, logical, implementation, and other changes may be made to the implementation. Therefore, the following detailed description should not be construed as limiting, and the scope of the present invention is limited only by the claims.

[0025] The present invention proposes a method for locating the initial position of the attenuation plate of a mechanical variable optical attenuator, which realizes the initial positioning of the attenuation plate by using an attenuation plate initial position positioning system. The structure of the attenuation plate initial position positioning system is as follows: Figure 2 As shown, it includes a motor 6, a light shield 2, an optical coupler 3, an encoding disc 4, and an encoding module 5. The encoding disc 4 and the encoding module 5 constitute an encoding system.

[0026] Motor 6 is a double-ended shaft motor with a reduction ratio of 1:N, i.e., the speed of the motor's fast terminals is N times the speed of the motor's slow terminals. In this embodiment, the reduction ratio of motor 6 is any one of 1:76, 1:141, 1:262, 1:485, 1:900, and 1:1670.

[0027] Attenuation plate 1 and light shield 2 are mounted on the slow-speed output shaft of motor 6, and their relative positions remain unchanged. Optocoupler 3 is positioned below light shield 2. When light shield 2 enters the groove of optocoupler 3, the attenuation blank area of ​​attenuation plate 1 is located exactly in the spatial optical path formed by the light input collimator and the light output collimator.

[0028] The encoder disc 4 is mounted on the fast-end output shaft of the motor 6. The encoder module 5 is arranged above the encoder disc 4. When the encoder disc 4 rotates, the CHI signal on the encoder disc 4 can be detected by the encoder module 5.

[0029] When motor 6 is started, attenuation plate 1 and light shield plate 2 rotate one revolution, while encoder disk 4 rotates N revolutions. Encoder module 5 detects the CHI signal on encoder disk 4 N times. With each revolution of attenuation plate 1 and light shield plate 2, the arc position of the CHI signal on encoder disk 4 from the detection point on encoder module 5 forms an angle of 18.4° to 19.4° compared to the previous revolution. After the attenuation plate rotates N revolutions, the arc position of the CHI signal on encoder disk 4 from the detection point on encoder module 5 returns to its initial value, with an error of no more than 5°.

[0030] See also Figure 3 The method for locating the initial position of the attenuation plate of the mechanical variable optical attenuator of the present invention comprises the following specific steps:

[0031] Step 1: Power on the variable optical attenuator.

[0032] Step 2: When the motor rotates at a constant speed in the forward direction (clockwise or counterclockwise), driving the light shield to enter the groove of the optocoupler, the optocoupler generates a level conversion signal, and the main control CPU controls the motor to stop rotating.

[0033] Step 3: The counter on the encoding module starts and begins counting. At the same time, the motor starts to rotate in the reverse direction (counterclockwise or clockwise) at a uniform speed. When the light shield rotates out of the groove of the optocoupler, the optocoupler generates a level conversion signal again. The motor continues to rotate for any time of 100ms, 110ms or 120ms. The main control CPU controls the motor to stop rotating. At this time, the counter has counted n encoding pulses.

[0034] Step 4: The motor rotates forward in steps of m (m < n) encoded pulses. When the light shield enters the optocoupler groove for the second time, the optocoupler generates a level conversion signal for the third time, and the main control CPU controls the motor to stop. Preferably, m is any natural number between 30 and 50.

[0035] Step 5: The motor rotates in the reverse direction according to m encoding pulse steps. When the light shield rotates out of the groove of the optocoupler for the second time, the optocoupler generates a level conversion signal for the fourth time. The main control CPU controls the motor to stop rotating and the encoding count is reset to zero.

[0036] Step 6: The motor steps in steps of n encoder pulses and continues to rotate in the reverse direction until the encoder module detects the CHI signal of the encoder disk. The motor stops rotating and reads the pulse number Pc in the encoder module counter. The pulse number Pc is the number of pulses of the encoder disk CHI signal from the encoder module detection point.

[0037] Step 7: By formula Calculate the arc of the CHI signal of the encoder disk from the detection point on the encoder module , where P is the total number of pulses in one cycle of the encoder disk. Check whether the angle of 120° to 240° is met. If so, this point is the initial position of the attenuator. If not, the motor rotates forward to the next circle and repeats steps 2 to 7 until the appropriate CHI position is found.

[0038] The present invention discloses a method for locating the initial position of an attenuator of a mechanically adjustable optical attenuator using a two-stage positioning system. The first-stage positioning system utilizes an optical coupler and employs a motor to advance in small steps to roughly position the attenuator, so that its coating blank area falls within the spatial optical path, thereby ensuring the insertion loss index of the adjustable optical attenuator. The second-stage positioning system utilizes a CHI signal from an encoding system to accurately locate the initial position of the attenuator. This ensures that the initial position of the attenuator remains unchanged as much as possible each time the adjustable optical attenuator is powered on, thereby ensuring the attenuation accuracy and repeatability of the adjustable optical attenuator.

[0039] It is not possible to describe all possible combinations of components or methods for the purposes of describing the above-described embodiments, but one of ordinary skill in the art will recognize that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to encompass all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, to the extent the term "comprising" is used in the specification or claims, the term is intended to be encompassed in a manner similar to the term "including," as explained in terms of "including," used as a transitional word in the claims. Furthermore, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or."

Claims

1. A method for initial positioning of an attenuation plate of a mechanical variable optical attenuator, characterized in that: The initial positioning of the attenuation plate is achieved by using an attenuation plate initial position positioning system; the attenuation plate initial position positioning system includes a motor, a light shield, an optical coupling device, an encoding disk, and an encoding module, and the encoding disk and the encoding module constitute an encoding system; the motor is a double-end output shaft motor with a reduction ratio of 1:N; the attenuation plate and the light shield are installed on the slow-end output shaft of the motor, the optical coupling device is arranged below the light shield, the encoding disk is installed on the fast-end output shaft of the motor, and the encoding module is arranged above the encoding disk; the specific method is as follows: Step 1: Power on the variable optical attenuator; Step 2: When the motor rotates forward at a constant speed and drives the light shield to rotate into the groove of the optocoupler, the optocoupler generates a level conversion signal, and the main control CPU controls the motor to stop rotating; Step 3: The counter on the encoding module starts to count, and the motor starts to rotate in the reverse direction at a constant speed. When the light shield rotates out of the groove of the optocoupler, the optocoupler generates a level conversion signal again, and the motor continues to rotate until the main control CPU controls the motor to stop. At this time, the counter counts n encoding pulses. Step 4: The motor rotates forward in steps of m encoded pulses. When the light shield rotates into the groove of the optocoupler for the second time, the optocoupler generates a level conversion signal for the third time, and the main control CPU controls the motor to stop rotating. Step 5: The motor rotates in the reverse direction according to m encoding pulse steps. When the light shield rotates out of the groove of the optocoupler for the second time, the optocoupler generates a level conversion signal for the fourth time. The main control CPU controls the motor to stop rotating and the encoding count is reset to zero. Step 6: The motor steps in steps of n encoding pulses and continues to rotate in the reverse direction until the encoding module detects the CHI signal of the encoding disk. The motor stops rotating and the pulse number Pc in the encoding module counter is read. The pulse number Pc is the number of pulses of the CHI signal of the encoding disk from the detection point of the encoding module. Step 7: By formula Calculate the arc distance of the CHI signal of the encoder disk from the detection point on the encoding module , where P is the total number of pulses in one cycle of the encoder disk; Whether the requirement of 120° to 240° is met, if so, the point is the initial position of the attenuation plate, if not, the motor rotates forward to the next circle, and steps 2 to 7 are repeated.

2. The method according to claim 1, characterized in that The reduction ratio of the motor is any one of 1:76, 1:141, 1:262, 1:485, 1:900 and 1:1670.

3. The method according to claim 1, characterized in that When the light blocking sheet enters the groove of the optical coupling device, the attenuation blank area of ​​the attenuation sheet is exactly located in the spatial light path formed by the light input collimator and the light output collimator.

4. The method according to claim 1, wherein In step 3, after the motor continues to rotate for any time period of 100ms, 110ms or 120ms, the main control CPU controls the motor to stop rotating.

5. The method according to claim 1, wherein Every time the attenuation plate and the light-blocking plate rotate one circle, the arc position of the CHI signal on the encoding disk from the detection point on the encoding module forms an angle of 18.4°~19.4° with that of the previous circle; after the attenuation plate rotates N circles, the arc position of the CHI signal on the encoding disk from the detection point on the encoding module returns to the initial arc.

6. The method according to claim 5, characterized in that After the attenuation plate rotates N times, the arc of the CHI signal on the encoding disk from the detection point on the encoding module returns to the initial arc, and the error with the initial arc is no more than 5°.

7. The method according to claim 1, characterized in that The m is less than n, and m is any natural number between 30 and 50.

Images