Automated Testing Method and System for MEMS Optical Switch Aging

Abstract

This invention provides an automated aging test method and system for MEMS optical switches. The test method uses an optical circulator to receive light sources from an EDFA laser and an EYDFA laser, and emits signal light to the MEMS optical switch. Multiple channels of the MEMS optical switch are cyclically switched, with the EYDFA laser turning off during switching and turning back on after switching to the next channel. The return light power of each channel of the MEMS optical switch obtained in the first cycle is recorded as a reference value. This measurement is repeated, and the return light power of each channel measured in multiple cycles is compared with the reference value. The magnitude of the change in the return light power of each channel is used to determine whether it is abnormal; if an abnormality is found, the cycle is stopped. This invention uses an integrated control method to connect and control the various modules, eliminating the need for manual operation during the test, thus improving work efficiency and reducing costs.

Description

Technical Field

[0001] This invention relates to the field of optical communication, specifically to an automated testing method and system for aging MEMS optical switches. Background Technology

[0002] An optical switch is a device that converts optical signals from one optical channel to another within a certain range. It has one or more selectable transmission windows and is a core component for realizing functions such as optical cross-connection, optical add-drop multiplexing, network monitoring, and self-healing protection. The principle of a MEMS optical switch is as follows: Figure 1 The diagram shows a micromirror array etched onto a silicon crystal. Through electrostatic or electromagnetic forces, this array rotates, altering the direction of light propagation to switch the optical path on and off. MEMS optical switches control the optical path by external control information and corresponding high / low voltage levels, which in turn control the lifting of the internal micromirrors.

[0003] The optical switch aging test is a test method that uses high temperature testing and high-power optical input to quickly measure the lifespan of the optical switch. Therefore, the optical switch needs to be placed in a high-temperature heating device and a high-power laser is introduced into the optical input end of the optical switch to accelerate the aging process.

[0004] Based on the accelerated life Arrhenius model (Equation 1.1) and the non-temperature stress Black model (Equation 1.2): Formula 1.1 Ea is the activation energy, k is the Boltzmann constant, T is the test environment temperature, and Ta is the aging acceleration temperature.

[0005] Formula 1.2 Wd and C are constants, j n is the current density, T is the ambient temperature, k is the Boltzmann constant, and Ea is the activation energy.

[0006] Taking the ten-year service life of a MEMS optical switch product at 25℃ and 200 mW input power as an example, and substituting the test results at 85℃ and 430 mW optical power input into the above formula, it is found that the ten-year service life of the MEMS optical switch under normal operating conditions is equivalent to one and a half months in the aging test.

[0007] Existing MEMS aging test technologies, such as Figure 2 As shown, the system used includes: 2-1. Pulsed laser: Outputs high-power pulsed laser, with a power of 400 mW or more.

[0008] 2-2. Circulator: Used to receive the return light from the optical switch, and the output return light is tested by an optical power meter.

[0009] 2-3. MEMS optical switch: It can switch the optical path of four channels. Each time the optical path is switched, the pulse laser needs to be turned off manually first, the optical path is switched by operating the light-cutting control circuit board, and then the pulse laser is turned on.

[0010] 2-4. Light-cutting control circuit board: The experimenter manually controls the circuit board to select the four-channel light-cutting of the MEMS optical switch.

[0011] 2-5. Optical Power Meter: The optical power of the optical switch returning light is detected by the optical power meter to obtain the return loss value of the optical switch.

[0012] The MEMS optical switch is placed in a heating device, and a high-power pulsed laser is used to input light into each of the four channels of the MEMS optical switch. The optical switch is then aged in a high-temperature constant-temperature device. At regular intervals, the performance parameters of the optical switch need to be tested by the experimenters. The return loss of the optical switch can be output to an optical power meter through a circulator. The insertion loss value of the optical switch can also be tested using an optical power meter. After the optical switch ages and fails, the return loss value will decrease by 10%. From the start of the aging experiment until the abnormal return loss of the MEMS optical switch is detected, the entire process takes more than a month. Therefore, the experimenters need to stay at the test platform for a long time, which consumes a lot of testing time and is time-consuming and labor-intensive. Summary of the Invention

[0013] To address the problems of existing technologies, this invention provides an automated testing method and system for the aging of MEMS optical switches. It uses integrated control to connect and control various modules, eliminating the need for manual operation during the testing process, thereby improving work efficiency and reducing costs.

[0014] This invention provides an automated aging test method for MEMS optical switches, comprising the following steps: 1) Set up the laser optical path; 2) The optical circulator receives light from the EDFA laser and the EYDFA laser, and emits signal light to the MEMS optical switch; 3) The MEMS optical switch cycles through multiple channels, with the EYDFA laser turning off during switching and turning on again after switching to the next channel; 4) The optical circulator receives the echo signal light returned by the MEMS optical switch, and the optical power meter counts the return optical power of each channel; 5) Record the return light power of each channel of the MEMS optical switch obtained in step 4) as the reference value. Repeat steps 3) and 4) multiple times. Compare the return light power of each channel measured in multiple cycles with the reference value. Determine whether it is abnormal based on the magnitude of the change in the return light power of the channel. If it is abnormal, stop the cycle.

[0015] Further improvements are made to the laser optical path described in step 1), which includes, in sequence, a DFB seed source, a polarization-maintaining isolator, a first acousto-optic modulator, an EDFA laser amplification module, a second acousto-optic modulator, an EYDFA laser amplification module, an optical circulator, and a MEMS optical switch. The two acousto-optic modulators are respectively connected to acousto-optic drivers that output radio frequency electrical signals. The EYDFA laser amplification module is connected to an ASE light source. The optical circulator is connected to an optical power meter, and the optical power meter is connected to a host computer.

[0016] The first acousto-optic modulator and its connected acousto-optic driver operate at 80 MHz, while the second acousto-optic modulator and its connected acousto-optic driver operate at 40 MHz. The DFB seed module has an input current of 90 to 100 mA, the EDFA laser amplification module has an input current greater than 500 mA, the EYDFA laser amplification module has an input current of 5 to 6 A, the total system output power is greater than 430 mW, and the ambient temperature is controlled at 85°C.

[0017] Further improvements include: in step 3), during the cyclic switching process of multiple channels of the MEMS optical switch, the switching frequency is 4 Hz, the opening time of each channel within 1 second is 250 ms, the laser is turned off within 4 ms before the optical switch switches and turned on 23 ms after the optical switch switches are completed.

[0018] Further improvements include: in step 4), when the optical circulator receives the echo signal light returned from the MEMS optical switch, the EDFA laser is turned off, and the EYDFA laser is turned on. During the optical switch aging test, it is necessary to pay attention to suppressing the SBS (Raman effect) phenomenon in the fiber laser. Therefore, a scheme is adopted where the DFB and EDFA modules are turned off, and only the EYDFA module is turned on. The EYDFA is a wide-line tube ASE light source, which can also reduce the fluctuation amplitude of the returned light power. The current of the EYDFA module should not be too high to prevent self-oscillation.

[0019] This invention also provides an automated aging test system for MEMS optical switches, including a pulsed laser module, a main control board module, a MEMS optical switch module, an optical power meter, a receiving device, a host computer, and a power supply module. The pulsed laser module is connected to the MEMS optical switch module to provide pulsed light input; the MEMS optical switch module is connected to the receiving device with an optical power meter; the main control board module is connected to the power supply module, the pulsed laser module, and the MEMS optical switch module respectively, controlling the operation of the laser and the optical switch and providing integrated control of the power supply module; the host computer is connected to the receiving device, the optical power meter, and the main control board module respectively, controlling each system, reading data, displaying the data, and saving the data.

[0020] In a further improvement, the pulsed laser module, the main control board module, and the MEMS optical switch module are housed within the housing.

[0021] As a further improvement, a heating device is provided at the MEMS optical switch module.

[0022] In a further improvement, the receiving device is an optical circulator with three ports: one port receives the light emitted by the amplification module, the second port emits signal light, and the third port receives the echo signal.

[0023] The beneficial effects of this invention are as follows: 1. By using integrated control to connect and control each module, no human intervention is required during the testing process, which improves work efficiency and reduces costs.

[0024] 2. The test data of each module can be presented intuitively through the host computer, ensuring the accuracy and scientific nature of the data.

[0025] 3. The use of self-amplifying (ASE) light source in the backlight testing stage can effectively suppress the stimulated Brillouin scattering (SBS) effect of fiber lasers.

[0026] 4. The entire system has advantages such as high degree of automation, low cost, accurate and scientific output data, fast response speed, and simple and convenient operation. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, 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.

[0028] Figure 1 This is a schematic diagram of the MEMS optical switch principle; Figure 2 This is a schematic diagram of an optical switch aging test. Figure 3 This is a schematic diagram of the overall block diagram of the MEMS optical switch aging automated testing system; Figure 4 This is a schematic diagram of the laser's optical path; Figure 5 Waveform diagrams for laser and optical switch operation; Figure 6 For control program logic block diagram.

[0029] Figure 7 The graph shows the return loss values ​​of the four channels of the optical switch under different test durations. Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The overall block diagram of the automated aging test system for MEMS optical switches provided by this invention is as follows: Figure 3 As shown, the system includes a pulsed laser module, a main control board module, a MEMS optical switch module, an optical power meter, a receiving device, a host computer, and a power supply module. The pulsed laser module is connected to the MEMS optical switch module to provide pulsed light input. The MEMS optical switch module is connected to the receiving device with an optical power meter. The main control board module is connected to the power supply module, the pulsed laser module, and the MEMS optical switch module to control the operation of the laser and the optical switch and provide integrated control of the power supply module. The host computer is connected to the receiving device, the optical power meter, and the main control board module to control each system, read data, display, and save the data.

[0032] 3-1. Pulsed Laser Module: Provides pulsed light input and is programmable.

[0033] 3-2. Main control board module: Integrated control of laser, optical switch and power supply module.

[0034] 3-3. MEMS Optical Switch Module: MEMS optical switch and optical switch control.

[0035] 3-4. Optical power meter: detects optical switch return loss.

[0036] 3-5. Receiving device: used for optical power reception.

[0037] 3-6. Host computer: Data reading, display, storage and system control.

[0038] 3-7, 24V DC power supply: supplies power to the system.

[0039] 3-8. Heating device: Used for heating during photoelectric switch aging tests. 3-9. Housing: To carry and encapsulate the laser and main control board.

[0040] The schematic diagram of the laser optical path used in this invention is shown below. Figure 4As shown, the device includes, in sequence, a DFB seed source, a polarization-maintaining isolator, a first acousto-optic modulator, an EDFA laser amplification module, a second acousto-optic modulator, an EYDFA laser amplification module, an optical circulator, and a MEMS optical switch. The two acousto-optic modulators are respectively connected to acousto-optic drivers that output radio frequency electrical signals. The EYDFA laser amplification module is connected to an ASE light source. The optical circulator is connected to an optical power meter, and the optical power meter is connected to a host computer.

[0041] 4-1. DFB seed source: provides signal light.

[0042] 4-2. Polarization maintaining isolator: Prevents backlight from returning to laser 1 and protects laser 1 from damage.

[0043] 4-3. 80MHz Acousto-Optical Modulator: The piezoelectric transducer of the acousto-optic crystal converts the output signal of the acousto-optic driver into ultrasonic waves that propagate within the acousto-optic crystal, forming a refractive index grating. When a laser beam passes through at a certain angle, Bragg diffraction occurs. The input light and the first-order diffracted light are coupled and output through an optical fiber. 4-4, 80MHz Acousto-optic Driver: Outputs a radio frequency electrical signal, which is applied to the piezoelectric transducer of the acousto-optic modulator via an impedance matching network.

[0044] 4-5. Laser Amplification Module: Amplifies the output light from the modulator to a suitable power.

[0045] 4-6, 40MHz acousto-optic modulator.

[0046] 4-7, 40MHz audio-visual driver.

[0047] 4-8. Laser amplification module.

[0048] 4-9. Optical Circulator: It has three ports. One port receives the light emitted by the amplification module, the second port emits signal light, and the third port receives the echo signal light.

[0049] 4-10. MEMS optical switch: Several tiny mirrors are etched on a silicon crystal. Through the action of electrostatic or electromagnetic forces, the micromirror array rotates, thereby changing the propagation direction of the input light to realize the function of opening and closing the optical path.

[0050] 4-11. Optical power meter: receiver optical switch return loss.

[0051] 4-12. Host computer: System integration and control, data storage and display.

[0052] The automated aging test method for MEMS optical switches includes the following steps: 1) Settings as follows Figure 4 The laser optical path shown; 2) The optical circulator receives light from the EDFA and EYDFA lasers and emits signal light to the MEMS optical switch. The operating waveforms of the laser and optical switch are shown in the figure. Figure 6 As shown; 3) The MEMS optical switch cycles through multiple channels, with the EYDFA laser turning off during switching and turning on again after switching to the next channel; 4) The optical circulator receives the echo signal light returned by the MEMS optical switch, and the optical power meter counts the return optical power of each channel; 5) Record the return light power of each channel of the MEMS optical switch obtained in step 4) as the reference value. Repeat steps 3) and 4) multiple times. Compare the return light power of each channel measured in multiple cycles with the reference value. Determine whether it is abnormal based on the magnitude of the change in the return light power of the channel. If it is abnormal, stop the cycle.

[0053] The overall working process can be divided into a high light intensity and high temperature aging stage and a return light power monitoring stage for each channel.

[0054] High light intensity and high temperature aging stage: The DFB seed module has an input current of 100 mA, the EDFA module has an input current of 500 mA, and the EYDFA module has an input current of 6 A (excessive current will cause self-oscillation). The total system output power is 430 mW, and the ambient temperature is stabilized at 85℃. The optical switch cycles through four channels at a frequency of 4 Hz. Each time the light is switched, the laser is turned off, and then turned back on after switching to the next channel. Figure 6 As shown, the optical switch turns on each channel for 250 ms within 1 second. The laser turns off 4 ms before the optical switch switches and turns on 23 ms after the optical switch switches are completed.

[0055] Each channel's return light power monitoring phase: The host computer controls the switching of the laser module's optical power and the switching of the optical switch via individual messages. Power monitoring for each optical switch channel is performed every 1 minute. The host computer extracts the real-time power from the optical power meter and displays it in its software, automatically saving the test data. During the optical switch aging test of the fiber laser, it is crucial to suppress the SBS phenomenon. Therefore, a scheme is adopted where the DFB and EDFA modules are turned off, and only the EYDFA module is turned on. The EYDFA is a wide-line tube ASE light source, which can also reduce the fluctuation amplitude of the return power. The current of the EYDFA module must not be too high to prevent self-oscillation effects.

[0056] The overall program framework is as follows Figure 7As shown, each link is controlled by messages, and commands are sent through RS232 and RS422 serial ports. The average return power of each channel of the optical switch in the first round of testing will be used as a reference value. The return power of each channel measured in each subsequent cycle will be compared with the reference value. If the change in the return power of a channel exceeds 10%, it is judged as abnormal and the cycle stops.

[0057] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. In particular, for the device embodiments, the above descriptions are merely preferred embodiments of the present invention. Since they are fundamentally similar to the method embodiments, the descriptions are relatively simple, and relevant parts can be referred to the descriptions of the method embodiments. The above descriptions are merely specific 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, without departing from the principle of the present invention, should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An automated aging test method for MEMS optical switches, employing an automated aging test system for MEMS optical switches, comprising a pulsed laser module, a main control board module, a MEMS optical switch module, an optical power meter, a receiving device, a host computer, and a power supply module, wherein, A pulsed laser module is connected to a MEMS optical switch module to provide pulsed light input; the MEMS optical switch module is connected to a receiving device with an optical power meter; the main control board module is connected to the power supply module, the pulsed laser module, and the MEMS optical switch module respectively, controlling the operation of the laser and the optical switch and providing integrated control of the power supply module; the host computer is connected to the receiving device, the optical power meter, and the main control board module respectively, controlling each system and reading, displaying, and saving data; characterized by including the following steps: 1) Set up the laser optical path; 2) The optical circulator receives light from the EDFA laser and the EYDFA laser, and emits signal light to the MEMS optical switch; 3) The MEMS optical switch cycles through multiple channels, with the EYDFA laser turning off during switching and turning on again after switching to the next channel; 4) The optical circulator receives the echo signal light returned by the MEMS optical switch, and the optical power meter counts the return optical power of each channel; 5) Record the return light power of each channel of the MEMS optical switch obtained in step 4) as the reference value. Repeat steps 3) and 4) multiple times. Compare the return light power of each channel measured in multiple cycles with the reference value. Determine whether it is abnormal based on the magnitude of the change in the return light power of the channel. If it is abnormal, stop the cycle.

2. The automated aging test method for MEMS optical switches according to claim 1, characterized in that: Step 1) The laser optical path includes, in sequence, a DFB seed source, a polarization-maintaining isolator, a first acousto-optic modulator, an EDFA laser amplification module, a second acousto-optic modulator, an EYDFA laser amplification module, an optical circulator, and a MEMS optical switch. The two acousto-optic modulators are respectively connected to acousto-optic drivers that output radio frequency electrical signals. The EYDFA laser amplification module is connected to an ASE light source. The optical circulator is connected to an optical power meter, and the optical power meter is connected to a host computer.

3. The automated aging test method for MEMS optical switches according to claim 2, characterized in that: The first acousto-optic modulator and its connected acousto-optic driver operate at 80MHz, while the second acousto-optic modulator and its connected acousto-optic driver operate at 40MHz.

4. The automated aging test method for MEMS optical switches according to claim 2, characterized in that: The DFB seed source has an input current of 90 to 100 mA, the EDFA laser amplification module has an input current of more than 500 mA, the EYDFA laser amplification module has an input current of 5 to 6 A, the total output power of the system is greater than 430 mW, and the ambient temperature is controlled at 85℃.

5. The automated aging test method for MEMS optical switches according to claim 1 or 2, characterized in that: In step 3), during the cyclic switching process of multiple channels of the MEMS optical switch, the switching frequency is 4 Hz. The time for each channel to be turned on within 1 second is 250 ms. The laser is turned off within 4 ms before the optical switch is switched and turned on 23 ms after the optical switch is switched.

6. The automated aging test method for MEMS optical switches according to claim 1 or 2, characterized in that: In step 4), when the optical circulator receives the echo signal light returned by the MEMS optical switch, the EDFA laser is turned off and the EYDFA laser is turned on.

7. The automated aging test method for MEMS optical switches according to claim 1, characterized in that: The pulsed laser module, main control board module, and MEMS optical switch module are housed within the housing.

8. The automated aging test method for MEMS optical switches according to claim 1, characterized in that: A heating device is provided at the MEMS optical switch module.

9. The automated aging test method for MEMS optical switches according to claim 1, characterized in that: The receiving device is an optical circulator with three ports: one port receives the light emitted by the amplification module, the second port emits signal light, and the third port receives the echo signal.

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