Dynamic filtering device, light amplification system and dynamic filtering method

Abstract

The embodiment of the invention discloses a dynamic filtering device, an optical amplification system and a dynamic filtering method. The dynamic filtering device can be applied to the optical amplification system. Specifically, a first filtering element in the dynamic filtering device is used for attenuating input target light. In addition, the first control unit adjusts the proportion of the target light passing through the first light filtering element by controlling the first light filtering element to move, and therefore the attenuation amount of the target light can be flexibly adjusted according to actual requirements. It is understood that the amplitude of attenuation of the target light by the first filtering element is related to the wavelength of the target light, that is to say, for the target light with a certain wavelength range, the first filtering element can specifically attenuate the target light at different wavelength positions to different degrees. It can be seen that the first filtering element provided by the invention is different from the VOA of which the attenuation is irrelevant to the wavelength, the insertion loss introduced by the dynamic filtering device adopting the first filtering element is relatively low, and the optimization of the noise coefficient is facilitated.

Description

Technical Field

[0001] Embodiments of the present application relate to the field of optical transmission, and in particular, to a dynamic filtering device, an optical amplification system, and a dynamic filtering method. Background Art

[0002] Optical amplifiers, especially erbium doped fiber amplifiers (EDFA), have been widely used in the field of communications, mainly to compensate for the loss of transmission optical fibers. EDFA has the characteristics of low noise and polarization independence, making ultra-long-distance non-relay transmission possible. The intrinsic gain spectrum of erbium-doped fiber in EDFA is usually ups and downs, and the difference between the maximum gain and the minimum gain is even close to 20dB.

[0003] The existing commercial gain adjustable technology is realized by adding variable optical attenuators (VOAs) between multiple optical amplifiers, and the gain adjustment is achieved by adjusting the attenuation of the VOA. However, the VOA will introduce a large insertion loss and the noise figure (NF) will be seriously degraded. Summary of the invention

[0004] The embodiments of the present application provide a dynamic filtering device, an optical amplification system and a dynamic filtering method. The dynamic filtering device introduces low insertion loss and is conducive to optimizing the noise coefficient.

[0005] In a first aspect, an embodiment of the present application provides a dynamic filtering device, which includes: an input port, an output port, a first control unit, and a first filter element. The first control unit is used to control the movement of the first filter element to adjust the proportion of the target light from the input port passing through the first filter element. The first filter element is used to attenuate the target light. Among them, the target light after attenuation by the first filter element is output from the output port. The target light is a multi-wavelength light, that is, the target light has a target wavelength range. As an example, in a scenario where the gain spectrum is flattened, the target wavelength range of the target light can be 1520nm-1580nm. As an example, in a scenario where bandpass filtering is implemented, the target light can cover light in the C band, L band, and S band. It should be understood that the amplitude of the attenuation of the target light by the first filter element is related to the wavelength of the target light in the target wavelength range. That is, the first filter element can specifically attenuate the target light at different wavelength positions in the target wavelength range to different degrees. It can be seen that the first optical filter element provided in the present application is different from the VOA whose attenuation is independent of the wavelength. The dynamic filtering device using the first optical filter element introduces lower insertion loss and is conducive to optimizing the noise coefficient.

[0006] In some possible implementations, for any two wavelengths within the target wavelength range, such as the first wavelength and the second wavelength. After the target light is amplified by the optical amplifier, the first gain of the target light of the first wavelength is greater than the second gain of the target light of the second wavelength. Correspondingly, the first attenuation amplitude of the first filter element to the target light of the first wavelength is greater than the second attenuation amplitude of the first filter element to the target light of the second wavelength. That is to say, within the target wavelength range, the greater the gain corresponding to the wavelength, the greater the attenuation amplitude corresponding to the wavelength. Moreover, the gain variation amplitude corresponding to the two wavelengths is the same or similar to the attenuation variation amplitude corresponding to the two wavelengths. For example, the absolute value of the difference between the gain variation amplitude between the first gain and the second gain and the attenuation variation amplitude between the first attenuation amplitude and the second attenuation amplitude is less than a preset value, which may be 1dB or 2dB, etc., and is not specifically restricted here. In this way, the dynamic filtering device can make the originally fluctuating gain spectrum of the target light flat.

[0007] In some possible implementations, the first control unit is specifically used to: obtain the average gain of the target light within the target wavelength range, and control the displacement of the first filter element according to the average gain of the target light within the target wavelength range. It should be understood that the average gain of the input target light within the target wavelength range is not fixed, and the average gain is related to the gain variation amplitude of the target light within the target wavelength range. Therefore, the first control unit flexibly adjusts the proportion of the first filter element intervening in the optical path according to the average gain, so that the gain spectrum of the target light with different average gains can be flattened, thereby being able to adapt to a variety of different application scenarios.

[0008] In some possible implementations, when the target light has a first average gain within the target wavelength range, the proportion of the target light passing through the first filter element is a first proportion. When the target light has a second average gain within the target wavelength range, the proportion of the target light passing through the first filter element is a second proportion. The first average gain is less than the second average gain, and the first proportion is greater than the second proportion. In other words, the smaller the average gain of the target light within the target wavelength range, the higher the proportion of the first filter element intervening in the optical path should be, which is conducive to ensuring that the gain spectrum of the target light becomes flat.

[0009] In some possible implementations, the first control unit is specifically used to: obtain the gain variation amplitude of the target light within the target wavelength range, and control the displacement of the first filter element according to the gain variation amplitude of the target light within the target wavelength range. It should be understood that the first control unit can also flexibly adjust the proportion of the first filter element intervening in the optical path by directly obtaining the gain variation amplitude of the target light, so as to make the gain spectrum of the target light with different gain variation amplitudes flat, thereby improving the scalability of the present solution.

[0010] In some possible implementations, when the target light has a first gain variation amplitude within the target wavelength range, the proportion of the target light passing through the first filter element is a first proportion. When the target light has a second gain variation amplitude within the target wavelength range, the proportion of the target light passing through the first filter element is a second proportion. The first gain variation amplitude is greater than the second gain variation amplitude, and the first proportion is greater than the second proportion. In other words, the greater the gain variation amplitude of the target light, the higher the proportion of the first filter element intervening in the optical path should be, which is conducive to ensuring that the gain spectrum of the target light becomes flat.

[0011] In some possible embodiments, the target light includes light in a first wavelength band and light in a second wavelength band, and the dynamic filtering device further includes a second filter element and a second control unit. The first filter element is used to filter out the light in the first wavelength band, and the second filter element is used to filter out the light in the second wavelength band. The second control unit is used to control the movement of the second filter element to adjust the proportion of the target light passing through the second filter element. In other words, the dynamic filtering device can also use multiple filter elements to achieve a function similar to a bandpass filter. Furthermore, each control unit independently adjusts the displacement size of the corresponding filter element according to actual needs to adjust the proportion of the target light passing through the filter element, thereby flexibly adjusting the attenuation amplitude of the target light in this wavelength band.

[0012] In some possible implementations, the dynamic filtering device further includes a light collimator. The light collimator is used to collimate the target light, and the first filter element is used to attenuate the collimated target light. It should be understood that the spot of the target light after the light beam is collimated is larger, so there is no need to make high requirements on the control accuracy of the first control unit. Even the first control unit with poor control accuracy can flexibly adjust the proportion of the target light passing through the first filter element by controlling the movement of the first filter element. Of course, for the first control unit with higher control accuracy, the light collimator may not be used.

[0013] In some possible implementations, the first control unit controls the movement of the first filter element by electrostatic, electrothermal, piezoelectric, magnetostrictive, electrostrictive, linear motor or electrically controlled screw threading, thereby increasing the flexibility of the implementation of the present solution. As an example, electrostatic, electrothermal or piezoelectric microelectromechanical systems (MEMS) can be used to control the first filter element.

[0014] In some possible implementations, the input port is used to connect an input optical fiber, and the output port is used to connect an output optical fiber.

[0015] In a second aspect, an embodiment of the present application provides an optical amplification system, which includes a first optical amplifier, a second optical amplifier, and a dynamic filtering device as described in any embodiment of the first aspect. The first optical amplifier is used to amplify input light and transmit the amplified light to the dynamic filtering device. The second optical amplifier is used to amplify light passing through the dynamic filtering device.

[0016] In some possible implementations, the optical amplification system further includes a gain flatten filter GFF, and the optical amplification system further includes a gain flatten filter (Gain flatten filter, GFF). Among them, the GFF is used to filter the light passing through the first optical amplifier. It should be understood that the GFF can also play a role in flattening the gain spectrum, but the GFF is mainly effective for light with a higher average gain, while the dynamic filtering device provided in the present application is more effective for light with a lower average gain. Therefore, the combination of the GFF and the dynamic filtering device can make the gain spectra of different specifications flat.

[0017] In a third aspect, an embodiment of the present application provides a dynamic filtering method, which is applied to a dynamic filtering device. The dynamic filtering device includes: an input port, an output port, a first control unit and a first filter element. The dynamic filtering method includes the following steps: controlling the movement of the first filter element by the first control unit to adjust the proportion of the target light from the input port passing through the first filter element. The target light is attenuated by the first filter element. Among them, the target light attenuated by the first filter element is output from the output port. The target light is a multi-wavelength light, that is, the target light has a target wavelength range. As an example, in a scenario where the gain spectrum is flattened, the target wavelength range of the target light can be 1520nm-1580nm. As an example, in a scenario where bandpass filtering is implemented, the target light can cover light of the C band, L band and S band. It should be understood that the amplitude of the attenuation of the target light by the first filter element is related to the wavelength of the target light within the target wavelength range. That is, the first filter element can attenuate the target light at different wavelength positions within the target wavelength range in a targeted manner. It can be seen that the first optical filter element provided in the present application is different from the VOA whose attenuation is independent of the wavelength. The dynamic filtering device using the first optical filter element introduces lower insertion loss and is conducive to optimizing the noise coefficient.

[0018] In some possible implementations, for any two wavelengths within the target wavelength range, such as the first wavelength and the second wavelength. After the target light is amplified by the optical amplifier, the first gain of the target light of the first wavelength is greater than the second gain of the target light of the second wavelength. Correspondingly, the first attenuation amplitude of the first filter element to the target light of the first wavelength is greater than the second attenuation amplitude of the first filter element to the target light of the second wavelength. That is to say, within the target wavelength range, the greater the gain corresponding to the wavelength, the greater the attenuation amplitude corresponding to the wavelength. Moreover, the gain change amplitude corresponding to the two wavelengths is the same or similar to the attenuation change amplitude corresponding to the two wavelengths. For example, the difference between the gain change amplitude corresponding to the two wavelengths and the attenuation change amplitude corresponding to the two wavelengths is less than 2dB or 1dB, and no specific restrictions are imposed here. In this way, the dynamic filtering device can flatten the originally fluctuating gain spectrum of the target light.

[0019] In some possible implementations, controlling the movement of the first filter element by the first control unit includes: obtaining the average gain of the target light within the target wavelength range by the first control unit, and controlling the displacement of the first filter element according to the average gain of the target light within the target wavelength range.

[0020] In some possible implementations, the smaller the average gain of the target light within the target wavelength range, the higher the proportion of the first filter element inserted into the optical path should be, which is beneficial to ensure that the gain spectrum of the target light becomes flat.

[0021] In some possible implementations, controlling the movement of the first filter element by the first control unit includes: obtaining the gain change amplitude of the target light within the target wavelength range by the first control unit, and controlling the displacement size of the first filter element according to the gain change amplitude of the target light within the target wavelength range.

[0022] In some possible implementations, the greater the gain variation of the target light is, the higher the proportion of the first filter element involved in the optical path should be, which is beneficial to ensure that the gain spectrum of the target light becomes flat.

[0023] In some possible embodiments, the target light includes light in a first wavelength band and light in a second wavelength band, and attenuating the target light through the first filter element includes: filtering out the light in the first wavelength band through the first filter element. The dynamic filtering device also includes a second filter element and a second control unit, and the method further includes: controlling the movement of the second filter element through the second control unit to adjust the proportion of the target light passing through the second filter element. Filtering out the light in the second wavelength band through the second filter element. Furthermore, each control unit independently adjusts the displacement size of the corresponding filter element according to actual needs to adjust the proportion of the target light passing through the filter element, thereby flexibly adjusting the attenuation amplitude of the target light in this wavelength band.

[0024] In some possible implementations, the dynamic filtering device further includes a light collimator. The method further includes: collimating the target light through the light collimator. Attenuating the target light through the first filter element includes: attenuating the collimated target light through the first filter element.

[0025] In some possible implementations, the first control unit controls the movement of the first filter element by electrostatic, electrothermal, piezoelectric, magnetostrictive, electrostrictive, linear motor or electrically controlled screw threading. As an example, electrostatic, electrothermal or piezoelectric MEMS can be used to control the first filter element.

[0026] In some possible implementations, the input port is used to connect an input optical fiber, and the output port is used to connect an output optical fiber.

[0027] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0028] The first filter element in the dynamic filtering device provided by the present application is used to attenuate the input target light. In addition, the first control unit adjusts the proportion of the target light passing through the first filter element by controlling the movement of the first filter element, so that the attenuation of the target light can be flexibly adjusted according to actual needs. It should be understood that the amplitude of the attenuation of the target light by the first filter element is related to the wavelength of the target light, that is, for target light with a certain wavelength range, the first filter element can specifically attenuate the target light at different wavelength positions to different degrees. It can be seen that the first filter element provided by the present application is different from the VOA whose attenuation is independent of the wavelength. The dynamic filtering device using the first filter element introduces a lower insertion loss and is conducive to optimizing the noise coefficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the first structure of the dynamic filtering device in the embodiment of the present application;

[0030] Figure 2 Schematic diagrams of several gain spectra before the target light is input into the dynamic filtering device;

[0031] Figure 3 Schematic diagrams of several gain spectra after the target light is output from the dynamic filtering device;

[0032] Figure 4 is a schematic diagram of an attenuation spectrum of the first filter element;

[0033] Figure 5 This is a schematic diagram of a first implementation method of controlling the movement of the first filter element in an embodiment of the present application;

[0034] Figure 6This is a schematic diagram of a second implementation method of controlling the movement of the first filter element in the embodiment of the present application;

[0035] Figure 7 This is a schematic diagram of the second structure of the dynamic filtering device in the embodiment of the present application;

[0036] Figure 8 This is a schematic diagram of a first implementation method of controlling the movement of multiple filter elements in an embodiment of the present application;

[0037] Fig. 9 This is a schematic diagram of a second implementation method of controlling the movement of multiple filter elements in an embodiment of the present application;

[0038] Fig.10 The noise coefficient comparison chart of this scheme and the traditional VOA scheme is shown in FIG.

[0039] Fig.11 This is a schematic diagram of the structure of an optical amplification system in an embodiment of the present application;

[0040] Fig.12 It is a schematic diagram of an embodiment of the dynamic filtering method in the embodiment of the present application. DETAILED DESCRIPTION

[0041] The embodiments of the present application provide a dynamic filtering device, an optical amplification system and a dynamic filtering method. The insertion loss introduced by the dynamic filtering device is low and is conducive to optimizing the noise coefficient. It should be noted that the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, rather than to limit a specific order or sequence. It should be understood that the above terms are interchangeable where appropriate so that the embodiments described in this application can be implemented in an order other than that described in this application. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0042] Figure 1 FIG. 1 is a schematic diagram of the first structure of the dynamic filtering device in the embodiment of the present application. Figure 1As shown, the dynamic filtering device includes: a first control unit 10, a first filter element 20, an input port 30 and an output port 40. Among them, the target light input from the input port 30 is transmitted to the output port 40 in the form of spatial light, that is, the input port 30 and the output port 40 do not need to be connected through a transmission medium such as an optical fiber or a waveguide. Of course, in some possible scenarios, the dynamic filtering device can be connected to other devices through optical fibers connected to the input port 30 and the output port 40 respectively. Specifically, the first control unit 10 is used to control the movement of the first filter element 20 to adjust the proportion of the target light from the input port passing through the first filter element 20. In other words, the proportion of the first filter element 20 intervening in the optical path of the target light can be flexibly adjusted according to actual needs. For example, all the target light passes through the first filter element 20, or part of the target light passes through the first filter element 20, or the target light does not pass through the first filter element 20 at all.

[0043] The first filter element 20 is used to attenuate the target light from the input port 30, and the target light attenuated by the first filter element 20 is output from the output port 40. It should be understood that in some possible scenarios, the input port 30 is connected to the pre-amplifier, and the output port 40 is connected to the post-amplifier. Assuming that the target light does not pass through the dynamic filtering device, the gain of the target light within the target wavelength range may fluctuate. The dynamic filtering device designed in this application can make the gain of the target light within the target wavelength range flat, wherein the amplitude of the attenuation of the target light by the first filter element 20 is related to the wavelength of the target light within the target wavelength range. It should be understood that the target light is amplified by the optical amplifier, and the target light has different gains at different wavelength positions within the target wavelength range. Therefore, the first filter element 20 designed in this application can specifically attenuate the target light at different wavelength positions within the target wavelength range to different degrees, so that the gain spectrum of the target light after passing through the first filter element 20 becomes flat.

[0044] As an example, for any two wavelengths within the target wavelength range, such as the first wavelength and the second wavelength, the first gain of the target light of the first wavelength is greater than the second gain of the target light of the second wavelength. Correspondingly, the first attenuation amplitude of the first filter element to the target light of the first wavelength is greater than the second attenuation amplitude of the first filter element to the target light of the second wavelength. That is to say, within the target wavelength range, the greater the gain corresponding to the wavelength, the greater the attenuation amplitude corresponding to the wavelength. Moreover, the gain variation amplitude corresponding to the two wavelengths is the same or similar to the attenuation variation amplitude corresponding to the two wavelengths. For example, the gain variation amplitude corresponding to the two wavelengths differs from the attenuation variation amplitude corresponding to the two wavelengths by less than 2dB or 1dB, and no specific restrictions are imposed here. In this way, the dynamic filtering device can make the originally fluctuating gain spectrum of the target light flattened. It should be understood that the flattening of the gain spectrum mentioned in the present application does not necessarily mean that the gain spectrum has no fluctuations at all. For example, a gain spectrum with a gain fluctuation amplitude less than 2dB can be regarded as a flat gain spectrum.

[0045] It should be noted that the original fluctuating gain spectrum of the target light can be detected in advance, and then, combined with the desired flat gain spectrum after the target light passes through the dynamic filtering device, the attenuation spectrum of the first filter element 20 can be designed, that is, the attenuation amplitude of the first filter element 20 for the target light at each wavelength position within the target wavelength range can be determined.

[0046] It should be understood that the gain spectrum of the target light passing through the optical amplifier but not the dynamic filtering device is referred to as the original gain spectrum, and the gain spectrum of the target light passing through the optical amplifier and the dynamic filtering device is referred to as the target gain spectrum. In a possible scenario, the front stage and the rear stage of the dynamic filtering device are respectively provided with a front stage optical amplifier and a rear stage optical amplifier. Figure 2 The following shows the original gain spectrum of the target light after passing through the subsequent optical amplifier. Figure 3 What is shown is the target gain spectrum after the target light passes through the subsequent optical amplifier.

[0047] Figure 2 Schematic diagrams of several original gain spectra of target light. Figure 2 The original gain spectra of four target lights with different average gains in the target wavelength range are shown. Figure 2 The horizontal axis represents the wavelength (in nm), and the vertical axis represents the gain (in dB). As an example, Figure 2 As shown, the target wavelength range of the target light is 1520nm-1580nm. Figure 2 The four gain spectra displayed are the gain spectrum with an average gain of 23dB, the gain spectrum with an average gain of 26dB, the gain spectrum with an average gain of 29dB, and the gain spectrum with an average gain of 32dB. Figure 2 It can be seen that the original gain spectrum of the target light is ups and downs.

[0048] Figure 3 Schematic diagram of several target gain spectra of target light. Figure 3 The horizontal axis represents the wavelength (in nm), and the vertical axis represents the gain (in dB). Figure 3 The target gain spectra of four target lights with different average gains within the target wavelength range are shown. Figure 3 and Figure 2 It can be seen from the comparison that the average gain of the target light remains stable, but the target gain spectrum becomes flatter than the original gain spectrum. Figure 3 As shown, the gain difference between the maximum gain value and the minimum gain value of the target light within the target wavelength range is less than or equal to 2 dB.

[0049] Figure 4 This is a schematic diagram of an attenuation spectrum of the first filter element. Figure 4 The horizontal axis represents the wavelength (in nm), and the vertical axis represents the attenuation (in dB). Figure 2 The gain spectrum with ups and downs shown becomes Figure 3 The flat gain spectrum shown in the figure can be designed specifically as follows Figure 4 The attenuation spectrum of the first filter element is shown in FIG. It can be seen that the attenuation spectrum of the first filter element is related to the wavelength, that is, the attenuation amplitude of the first filter element at different wavelength positions may be different. Figure 2 Taking the gain spectrum shown in FIG. 1 as an example, the gain of the target light with a wavelength near 1530nm is the lowest, and the gain of the target light with a wavelength near 1570nm is the highest. Figure 4 As shown, the first filter element has the lowest attenuation amplitude for target light with a wavelength near 1530nm, and the first filter element has the highest attenuation amplitude for target light with a wavelength near 1570nm. In other words, the first filter element attenuates the target light at a wavelength position with a higher gain to a greater extent, and the first filter element attenuates the target light at a wavelength position with a lower gain to a lesser extent, thereby flattening the originally fluctuating gain spectrum. Figure 4 and Figure 2 It can be seen from the comparison that the gain change trend of the target light is the same as the attenuation change trend of the target light by the first filter element.

[0050] It should be noted that if the gain variation amplitude of the target light within the target wavelength range is larger, it means that the jitter of the gain spectrum of the target light is larger, and the proportion of the first filter element 20 intervening in the optical path of the target light should also be higher, so that the first filter element 20 can exert the attenuation effect on the target light to a greater extent, thereby ensuring that the gain spectrum with larger jitter is flattened. Correspondingly, if the gain variation amplitude of the target light within the target wavelength range is smaller, it means that the jitter of the gain spectrum of the target light is smaller, and the proportion of the first filter element 20 intervening in the optical path of the target light can be reduced accordingly to weaken the attenuation effect of the first filter element 20 on the target light, so that the gain spectrum with smaller jitter can be flattened. That is to say, in a possible implementation, the first control unit 10 adjusts the displacement of the first filter element 20 according to the gain variation amplitude of the target light within the target wavelength range.

[0051] It should be noted that the gain variation range of the target light within the target wavelength range is related to the average gain of the target light within the target wavelength range. Figure 2 It can be seen that when the average gain of the target light is 23 dB, the gain variation of the target light is the largest, and as the average gain of the target light increases, the gain variation of the target light decreases. Then, in another possible implementation, the first control unit 10 controls the displacement of the first filter element 20 according to the average gain of the target light within the target wavelength range. It should be understood that the smaller the average gain of the target light within the target wavelength range, the higher the proportion of the first filter element 20 intervening in the optical path of the target light.

[0052] It should be understood that the average gain of the target light is not fixed, and the present application does not limit the specific average gain range. Figure 2 As shown, the average gain of the target light is between 23dB and 32dB. Under the premise that the average gain range of the target light is determined, for each average gain of the target light within the range, the first control unit 10 will correspondingly control the displacement size of the first filter element 20 to adjust the proportion of the first filter element 20 intervening in the optical path of the target light. The specific correspondence between the average gain of the target light and the proportion of the first filter element 20 intervening in the optical path of the target light shall be subject to actual application and is not limited here. As an example, if the average gain of the target light is 23dB, all the target light passes through the first filter element 20; if the average gain of the target light is 24dB, 90% of the target light passes through the first filter element 20; if the average gain of the target light is 25dB, 80% of the target light passes through the first filter element 20; ...; if the average gain of the target light is 32dB, all the target light does not pass through the first filter element 20.

[0053] Alternatively, if Figure 1As shown, the dynamic filtering device further includes a light collimator 50, and the target light input from the input port 30 will first pass through the light collimator 50 for beam collimation. It should be understood that the spot of the target light after beam collimation is larger, so there is no need to make high requirements on the control accuracy of the first control unit 10, and even the first control unit 10 with poor control accuracy can flexibly adjust the proportion of the target light passing through the first filter element 20 by controlling the movement of the first filter element 20. Of course, for the first control unit 10 with higher control accuracy, the light collimator 50 may not be used.

[0054] It should be noted that the present application does not limit the direction in which the first control unit 10 controls the first filter element 20 to move, and two possible implementations are provided below. Figure 5 This is a schematic diagram of a first implementation method of controlling the movement of the first filter element in an embodiment of the present application. Figure 6 FIG. 2 is a schematic diagram of a second implementation method of controlling the movement of the first filter element in the embodiment of the present application. Figure 5 As shown, the first control unit 10 controls the first filter element 20 to move in the first direction. Figure 6 As shown, the first control unit 10 controls the first filter element 20 to move in the second direction. It can be seen that the first direction is perpendicular to the second direction, which expands the application scenarios adapted by this solution.

[0055] It should be noted that the present application does not limit the specific type of the first control unit 10. For example, the first control unit 10 may control the movement of the first filter element 20 by electrostatic, electrothermal, piezoelectric, magnetostrictive, electrostrictive, linear motor or electrically controlled screw threading. As an example, electrostatic, electrothermal or piezoelectric microelectromechanical systems (MEMS) may be used to control the first filter element.

[0056] In some other possible scenarios, the dynamic filtering device may also use multiple filter elements to achieve a function similar to a bandpass filter. This implementation is introduced below.

[0057] Figure 7 FIG. 2 is a schematic diagram of the second structure of the dynamic filtering device in the embodiment of the present application. Figure 1 The structure shown, such as Figure 7 As shown, the dynamic filtering device includes a plurality of filter elements and a plurality of control units corresponding to the plurality of filter elements. The present application does not limit the specific number of filter elements and control units, for example Figure 7The system shown includes: a control unit 101, a control unit 102, ..., a control unit 10n and filter elements 201, filter elements 202, ..., filter elements 20n. Each control unit is used to control the movement of the corresponding filter element to adjust the proportion of the filtered target light passing through the filter element. In some possible implementations, the control units and the filter elements may not correspond one to one, that is, the number of control units may be less than the number of filter elements. For example, all filter elements may be controlled by one control unit. For another example, different control units respectively control some filter elements.

[0058] It should be understood that in this scenario, the attenuation amplitude of each filter element on the target light is also related to the wavelength of the target light within the target wavelength range. For example, filter element 201 is used to filter out the target light of the first band within the target wavelength range, and pass the target light of other bands, that is, the filter element 201 has a larger attenuation amplitude for the target light of the first band, and a smaller attenuation amplitude for the target light of other bands. For another example, filter element 202 is used to filter out the target light of the second band within the target wavelength range, and pass the target light of other bands. That is to say, filter element 202 has a larger attenuation amplitude for the target light of the second band, and a smaller attenuation amplitude for the target light of other bands. Further, each control unit independently adjusts the displacement size of the corresponding filter element according to actual needs to adjust the proportion of the target light passing through the filter element, thereby flexibly adjusting the attenuation amplitude of the target light in this band.

[0059] It should be noted that for Figure 7 In the illustrated implementation manner, the present application also does not limit the direction in which each control unit controls the corresponding first filter element to move. Two possible implementations are provided below. Figure 8 This is a schematic diagram of a first implementation method of controlling the movement of multiple filter elements in an embodiment of the present application. Fig. 9 This is a schematic diagram of a second implementation method of controlling the movement of multiple filter elements in the embodiment of the present application. Figure 8 As shown, each control unit controls the corresponding first filter element to move in the first direction. Fig. 9 As shown, each control unit controls the corresponding filter element to move in the second direction. In some other possible implementations, some control units may control the corresponding filter element to move in the first direction, and another control unit may control the corresponding filter element to move in the second direction.

[0060] From the above introduction, it can be known that the first filter element in the dynamic filtering device provided by the present application is used to attenuate the input target light. In addition, the first control unit adjusts the proportion of the target light passing through the first filter element by controlling the movement of the first filter element, so that the attenuation of the target light can be flexibly adjusted according to actual needs. It should be understood that the amplitude of the attenuation of the target light by the first filter element is related to the wavelength of the target light, that is, for target light with a certain wavelength range, the first filter element can specifically attenuate the target light at different wavelength positions to different degrees. It can be seen that the first filter element provided by the present application is different from the VOA whose attenuation is independent of the wavelength. The dynamic filtering device using the first filter element introduces a lower insertion loss and is conducive to optimizing the noise coefficient.

[0061] Fig.10 This is a noise coefficient comparison chart between this solution and the traditional VOA solution. Fig.10 The horizontal axis represents the wavelength (in nm), and the vertical axis represents the noise figure (in dB). Fig.10 It can be seen that this scheme significantly optimizes the noise figure compared with the traditional VOA scheme.

[0062] The following introduces the scenario in which the dynamic filtering device is applied to the optical amplification system.

[0063] Fig.11 FIG. 1 is a schematic diagram of the structure of an optical amplification system in an embodiment of the present application. Fig.11 As shown, the optical amplification system includes: a dynamic filtering device 1, a front-stage optical amplifier 2, and a rear-stage optical amplifier 3. The dynamic filtering device 1 can be the dynamic filtering device introduced in any of the above embodiments, which will not be described here. The front-stage optical amplifier 2 is used to amplify the input light and transmit the amplified light to the dynamic filtering device 1. The rear-stage optical amplifier 3 is used to amplify the light passing through the dynamic filtering device 1. In some possible scenarios, the optical amplification system may also retain only one of the front-stage optical amplifier 2 and the rear-stage optical amplifier 3.

[0064] Optionally, the optical amplification system further includes a gain flatten filter (GFF) 4. The GFF 4 is used to filter the light passing through the pre-stage optical amplifier 2. It should be understood that the GFF can also play a role in flattening the gain spectrum, but the GFF is mainly effective for light with a higher average gain, while the dynamic filtering device provided in the present application is more effective for light with a lower average gain. Therefore, the combination of the GFF 4 and the dynamic filtering device 1 can make the gain spectra of different specifications flat.

[0065] In some possible scenarios, the GFF can also be integrated into the dynamic filtering device. For example, the position of the GFF is fixed, that is, all the light input to the dynamic filtering device passes through the GFF. If the input light has a higher average gain, the GFF can flatten the gain spectrum of the light, and the first filter element does not need to be intervened in the optical path, that is, the input light does not need to pass through the first filter element. If the input light has a lower average gain, the GFF cannot flatten the gain spectrum of the light, and the first filter element needs to be intervened in the optical path to flatten the gain spectrum of the light, that is, the input light needs to pass through the first filter element, and the proportion of the light passing through the first filter element is flexibly adjustable.

[0066] The following is an introduction to the dynamic filtering method provided in the embodiments of the present application.

[0067] Fig.12 1 is a schematic diagram of an embodiment of the dynamic filtering method in the embodiment of the present application. It should be noted that the dynamic filtering method is implemented based on the dynamic filtering device introduced above. For the introduction of the dynamic filtering device, reference can be made to the relevant descriptions of the above embodiments, which will not be repeated here. In this example, the dynamic filtering method includes the following steps.

[0068] 1201. Control the movement of the first filter element through a first control unit.

[0069] In this embodiment, the proportion of the first filter element connected to the optical path can be adjusted by controlling the movement of the first filter element, which is equivalent to adjusting the proportion of the target light from the input port passing through the first filter element. It should be understood that the first control unit drives the first filter element in a manner including but not limited to MEMS, electrothermal, piezoelectric, magnetostrictive, electrostrictive, linear motor or electrically controlled screw threading.

[0070] In one possible implementation, the first control unit adjusts the displacement of the first filter element according to the gain variation of the target light within the target wavelength range. In another possible implementation, the first control unit controls the displacement of the first filter element according to the average gain of the target light within the target wavelength range.

[0071] 1202. Attenuate the target light through a first filter element.

[0072] It should be understood that the target light has a target wavelength range, and the gain of the target light may fluctuate within the target wavelength range. The attenuation amplitude of the target light by the first filter element is related to the wavelength of the target light within the target wavelength range. In other words, the first filter element designed in the present application can specifically attenuate the target light at different wavelength positions within the target wavelength range to different degrees, so that the gain spectrum of the target light after passing through the first filter element becomes flat.

[0073] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application is described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A dynamic filtering device, characterized in that: include: An input port, an output port, a first control unit and a first filter element; The first control unit is used to control the movement of the first filter element to adjust the proportion of the target light from the input port passing through the first filter element; The first filter element is used to attenuate the target light, wherein the target light attenuated by the first filter element is output from the output port, the target light has a target wavelength range, and the attenuation amplitude of the target light by the first filter element is related to the wavelength of the target light within the target wavelength range.

2. The dynamic filtering device according to claim 1, characterized in that: The target wavelength range includes a first wavelength and a second wavelength, the target light of the first wavelength has a first gain after amplification, the target light of the second wavelength has a second gain after amplification, the first gain is greater than the second gain, the first attenuation amplitude of the first filter element for the target light of the first wavelength is greater than the second attenuation amplitude of the first filter element for the target light of the second wavelength, and the absolute value of the difference between the gain change amplitude between the first gain and the second gain and the attenuation change amplitude between the first attenuation amplitude and the second attenuation amplitude is less than a preset value.

3. The dynamic filtering device according to claim 1 or 2, characterized in that: The target light is amplified by an optical amplifier, and the first control unit is specifically used for: Obtaining an average gain of the target light within the target wavelength range; The displacement size of the first filter element is controlled according to the average gain of the target light within the target wavelength range.

4. The dynamic filtering device according to claim 3, characterized in that: The average gain of the target light within the target wavelength range is inversely proportional to the ratio of the target light passing through the first filter element.

5. The dynamic filtering device according to claim 1 or 2, characterized in that: The target light is amplified by an optical amplifier, and the first control unit is specifically used for: Acquire a gain variation amplitude of the target light within the target wavelength range; The displacement of the first filter element is controlled according to the gain variation amplitude of the target light within the target wavelength range.

6. The dynamic filtering device according to claim 5, characterized in that: The gain variation amplitude of the target light within the target wavelength range is proportional to the ratio of the target light passing through the first filter element.

7. The dynamic filtering device according to claim 1, characterized in that: The target light includes light in a first wavelength band and light in a second wavelength band, and the first filter element is used to filter out the light in the first wavelength band; The dynamic filtering device further comprises a second filter element and a second control unit, wherein the second filter element is used to filter out light of a second wavelength band; The second control unit is used to control the movement of the second filter element to adjust the proportion of the target light passing through the second filter element.

8. The dynamic filtering device according to any one of claims 1 to 7, characterized in that: The dynamic filtering device also includes a light collimator; The light collimator is used to collimate the target light; The first filter element is used to attenuate the collimated target light.

9. The dynamic filtering device according to any one of claims 1 to 8, characterized in that: The first control unit controls the movement of the first filter element by electrostatic, electrothermal, piezoelectric, magnetostrictive, electrostrictive, linear motor or electrically controlled threaded advancement.

10. The dynamic filtering device according to any one of claims 1 to 9, characterized in that: The input port is used to connect to an input optical fiber, and the output port is used to connect to an output optical fiber.

11. An optical amplification system, characterized in that: include: A first optical amplifier, a second optical amplifier and a dynamic filtering device as claimed in any one of claims 1 to 10; The first optical amplifier is used to amplify the input light and transmit the amplified light to the dynamic filtering device; The second optical amplifier is used to amplify the light passing through the dynamic filtering device.

12. The optical amplification system according to claim 11, characterized in that: The optical amplification system also includes a gain flattening filter GFF; The GFF is used to filter the light passing through the first optical amplifier.

13. A dynamic filtering method, characterized in that: The method is applied to a dynamic filtering device, the dynamic filtering device comprising: an input port, an output port, a first control unit and a first filter element, and the method comprises: Controlling the movement of the first filter element by the first control unit to adjust the proportion of the target light from the input port passing through the first filter element; The target light is attenuated by the first filter element, wherein the target light attenuated by the first filter element is output from the output port, and the attenuation amplitude of the target light by the first filter element is related to the wavelength of the target light.

14. The method according to claim 13, characterized in that The target wavelength range includes a first wavelength and a second wavelength, the target light of the first wavelength has a first gain after amplification, the target light of the second wavelength has a second gain after amplification, the first gain is greater than the second gain, the first attenuation amplitude of the first filter element for the target light of the first wavelength is greater than the second attenuation amplitude of the first filter element for the target light of the second wavelength, and the absolute value of the difference between the gain change amplitude between the first gain and the second gain and the attenuation change amplitude between the first attenuation amplitude and the second attenuation amplitude is less than a preset value.

15. The method according to claim 13 or 14, characterized in that The target light is amplified by the optical amplifier, and the first control unit controls the movement of the first filter element, which includes: The average gain of the target light within the target wavelength range is acquired by the first control unit, and the displacement of the first filter element is controlled according to the average gain of the target light within the target wavelength range.

16. The method according to claim 15, characterized in that The average gain of the target light within the target wavelength range is inversely proportional to the ratio of the target light passing through the first filter element.

17. The method according to claim 13 or 14, characterized in that The target light is amplified by the optical amplifier, and the first control unit controls the movement of the first filter element, which includes: The gain variation amplitude of the target light within the target wavelength range is acquired by the first control unit, and the displacement size of the first filter element is controlled according to the gain variation amplitude of the target light within the target wavelength range.

18. The method according to claim 17, characterized in that The gain variation amplitude of the target light within the target wavelength range is proportional to the ratio of the target light passing through the first filter element.

19. The method according to claim 13, characterized in that The target light includes light in a first wavelength band and light in a second wavelength band, and attenuating the target light by using the first filter element includes: Filter out light of a first wavelength band by using the first filter element; The dynamic filtering device further includes a second filter element and a second control unit, and the method further includes: Controlling the movement of the second filter element by the second control unit to adjust the proportion of the target light passing through the second filter element; The light of the second wavelength band is filtered out by the second filter element.

20. The method according to any one of claims 13 to 19, characterized in that The dynamic filtering device further includes a light collimator, and the method further includes: collimating the target light by the light collimator; Attenuating the target light by the first filter element includes: The collimated target light is attenuated by the first filter element.

21. The method according to any one of claims 13 to 20, characterized in that The first control unit controls the movement of the first filter element by electrostatic, electrothermal, piezoelectric, magnetostrictive, electrostrictive, linear motor or electrically controlled threaded advancement.

22. The method according to any one of claims 13 to 21, characterized in that The input port is used to connect to an input optical fiber, and the output port is used to connect to an output optical fiber.

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