Optical attenuator with isolation function

Abstract

The utility model provides an optical attenuator with an isolation function, which comprises a double-core tail fiber, an incident optical fiber and an emergent optical fiber are arranged in the double-core tail fiber, and a birefringent crystal is arranged at the emergent end of the double-core tail fiber; a half-wave plate is arranged at one end, far away from the double-core tail fiber, of the birefringent crystal, and the half-wave plate is only arranged on one light path of the birefringent crystal; a rotating device, a focusing lens and a reflecting mirror are sequentially arranged on the side, away from the birefringent crystal, of the half-wave plate, the reflecting mirror is fixed to the rotating device, and the rotating device can drive the reflecting mirror to rotate so as to change the angle of a reflected light beam; the first end face, close to the rotating device, of the focusing lens is a plane, and the rotating device is fixed to the first end face of the focusing lens through an adhesive. The optical attenuator with the isolation function is low in assembly process difficulty, and the production cost of the optical attenuator can be reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of optical communication device, specifically, it is a kind of optical attenuator with isolation function. BACKGROUND

[0002] In optical fiber communication system, the role of optical attenuator is to adjust the intensity of optical signal.According to whether the intensity attenuation of optical signal can be adjusted, optical attenuator can be divided into fixed attenuator and variable attenuator, wherein, the attenuation amount of fixed attenuator for the intensity adjustment of optical signal is fixed, and cannot be adjusted, while variable attenuator can adjust the attenuation amount of optical signal according to actual use needs, to adapt to different transmission conditions.

[0003] On the other hand, optical isolator is used to ensure that optical signal can only be transmitted in forward direction, to avoid interference of reflected light on light source.In the design of traditional optical fiber communication system, optical attenuator and optical isolator are usually two independent devices, as many devices need to use optical attenuator and optical isolator at the same time, which not only increases the volume and complexity of equipment, but also limits the integration and flexibility of system.

[0004] The Chinese utility model patent with publication number CN222299845U discloses a coaxial packaged VOA+ISO function integrated device, which has a pin assembly, a polarization assembly, a collimating lens, a rotatory assembly and a rotating mirror chip, the pin assembly emits optical signal, the polarization assembly, the collimating lens, the rotatory assembly and the rotating mirror chip are sequentially arranged along the optical path; the polarization assembly is arranged at one end of the pin assembly towards the collimating lens, and the rotatory assembly is arranged at one end of the collimating lens towards the rotating mirror chip; by adjusting the angle of the rotating mirror chip, the optical signal emitted by the pin assembly is reflected back to the pin assembly at different angles, so as to adjust the receiving area of the pin assembly for optical signal, and further realize power attenuation adjustment of optical signal; the polarization assembly and the rotatory assembly are used to isolate the interference light input from outside to the pin assembly.

[0005] However, since the existing device uses collimating lens, the Faraday rotator is arranged at the light emitting side of the collimating lens, the purpose is to realize integrated packaging of collimating lens, magnetic ring, Faraday rotator and the like, that is, the existing device needs to package the collimating lens, magnetic ring, Faraday rotator and rotating mirror chip together, which leads to great difficulty in production process of device, and further leads to high production cost of device. SUMMARY

[0006] The utility model aims at providing a kind of optical attenuator with isolation function, which has simple assembly process and low production cost.

[0007] In order to achieve the above-mentioned purpose, the optical attenuator with the isolation function has a double-core tail fiber, the double-core tail fiber is provided with an incident optical fiber and an emergent optical fiber, and the emergent end of the double-core tail fiber is provided with a birefringent crystal; a half-wave plate is arranged at the end of the birefringent crystal away from the double-core tail fiber, and the half-wave plate is arranged on only one light path of the birefringent crystal; a rotating device, a focusing lens and a reflecting mirror are sequentially arranged on the side of the half-wave plate away from the birefringent crystal, the reflecting mirror is fixed on the rotating device, and the rotating device can drive the reflecting mirror to rotate to change the angle of the reflected light beam; wherein the first end face of the focusing lens close to the rotating device is a plane, and the rotating device is fixed on the first end face of the focusing lens through an adhesive; the rotating device and the focusing lens are packaged into a module, and the focusing lens and the reflecting mirror are separately arranged; and the rotating device comprises a micro-electromechanical device, and the micro-electromechanical device is fixed on the metal base through an adhesive.

[0008] As can be seen from the above scheme, since the first end face of the focusing lens close to the rotating device is a plane, the rotating device can be adhered to the first end face of the focusing lens, and the focusing lens and the reflecting mirror can be separately arranged, that is, the focusing lens and the reflecting mirror do not need to be integrated in a module, the assembly difficulty of the optical attenuator is reduced, and the production cost of the optical attenuator is reduced.

[0009] One preferred scheme is that the second end face of the focusing lens away from the rotating device is an arc surface. It can be seen that the focusing lens used is a spherical focusing lens, that is, a C-lens, and the focal point of this focusing lens is far away from the curved surface of the lens, which is conducive to arranging the reflecting mirror at a relatively far position, thereby facilitating the separate arrangement of the focusing lens and the reflecting mirror.

[0010] An optional scheme is that the focusing lens is a self-focusing lens, and the second end face of the focusing lens away from the rotating device is a plane.

[0011] A further scheme is that a magnetic ring is arranged outside the rotating device. Alternatively, the rotating device is a rotating device with a magnetic field strength.

[0012] As can be seen, by using the rotating device with a magnetic field strength, it is not necessary to arrange a magnet outside the rotating device, and the volume of the optical attenuator can be further reduced.

[0013] A further scheme is that the rotating device covers the two light paths of the focusing lens, and the optical rotation angle of the rotating device is 22.5°.

[0014] As can be seen, since the optical signal needs to be reflected by the reflecting mirror, the optical signal passes through the rotating device twice, and the polarization direction is rotated by 90° relative to the initial state when the optical signal passes through the rotating device for the second time, which is equivalent to the exchange of normal light and abnormal light, and in the forward light path, the two optical signals can be combined in the birefringent crystal.

[0015] Alternatively, the rotating device only covers one light path of the focusing lens, and the rotating angle of the rotating device is 45°.

[0016] Since the rotating device only covers one light path of the focusing lens, the volume of the rotating device is small, which is beneficial to the assembly of the optical attenuator.

[0017] Further, the metal base has a plurality of pins, and the pads on the micro-electro-mechanical device are bonded to the plurality of pins by gold wires.

[0018] Therefore, the connection between the pads on the micro-electro-mechanical device and the metal base is realized by gold wire bonding, which has high process reliability and can accurately control the operation of the micro-electro-mechanical device.

[0019] Further, the focusing lens and the rotating device are separately packaged. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a schematic diagram of a forward light path of the optical attenuator with an isolation function according to the first embodiment of the present application.

[0021] Figure 2 is a schematic diagram of a reverse light path of the optical attenuator with an isolation function according to the first embodiment of the present application.

[0022] Figure 3 is a schematic diagram of a forward light path of the optical attenuator with an isolation function according to the second embodiment of the present application.

[0023] Figure 4 is a schematic diagram of a forward light path of the optical attenuator with an isolation function according to the third embodiment of the present application.

[0024] The present application will be further described below in combination with the drawings and embodiments. DETAILED DESCRIPTION

[0025] The optical attenuator with an isolation function according to the present application is a variable optical attenuator, that is, the attenuation amount of the optical signal of the optical attenuator can be adjusted according to actual requirements, for example, by changing the angle of the reflecting mirror to reduce the optical power of the reflected light signal coupled to the outgoing optical fiber, thereby changing the attenuation amount of the optical signal. Moreover, the optical attenuator according to the present application has an isolation function, that is, can isolate the back light to avoid interference of the back light on the incident optical signal.

[0026] First embodiment:

[0027] Referring to Figure 1The optical attenuator with the isolation function has a double-core pigtail 101, and an incident optical fiber 111 and an emergent optical fiber 112 are arranged in the double-core pigtail 101. The externally input optical signal can be incident to the incident optical fiber 111 and emergent from the emergent optical fiber 112 after being attenuated. Since the optical attenuator has the isolation function, if the optical signal is incident from the emergent optical fiber 112, it cannot be emergent from the incident optical fiber 111.

[0028] A birefringent crystal 102 is arranged at the emergent end of the double-core pigtail 101, and the birefringent crystal 102 covers two light paths of the double-core pigtail 101. When the optical signal passes through the birefringent crystal 102, it can be divided into two polarized lights with perpendicular polarized directions, i.e. normal light and abnormal light. A half-wave plate 115 is arranged at the end of the birefringent crystal 102 far from the double-core pigtail 101, and the half-wave plate 115 covers one light path of the birefringent crystal 102. Figure 1 It can be seen that the half-wave plate 115 is arranged only on one light path of the birefringent crystal 102, i.e. only the incident optical signal or the emergent optical signal can pass through the half-wave plate 115. In the embodiment, the half-wave plate 115 is a 1 / 2 wave plate with an optical axis of 22.5°, so that when the polarized light passes through the half-wave plate 115, the polarized direction thereof is rotated by 45°.

[0029] A rotating device 103 is arranged at the side of the half-wave plate 115 far from the birefringent crystal 102, and the rotating device 103 is a Faraday rotator in the embodiment. A magnet 104 is arranged outside the rotating device 103. In the embodiment, the rotating device 103 covers two light paths of the birefringent crystal 102, so that both the incident optical signal and the emergent optical signal pass through the rotating device 103. Moreover, the rotating angle of the rotating device is 22.5°.

[0030] A focusing lens 105 is arranged at the side of the rotating device 103 far from the half-wave plate 115. The first end face 106 of the focusing lens 105 close to the rotating device 103 is a plane, and the second end face 107 of the focusing lens 105 far from the rotating device 103 is a curved surface. Therefore, the focusing lens 105 is a spherical focusing lens rather than a self-focusing lens, and the focal point of the focusing lens is far from the end face of the focusing lens. Moreover, since the first end face 106 is a plane, the rotating device 103 can be fixed on the first end face 106 by an adhesive. In this way, the rotating device 103 and the focusing lens 105 are packaged into a module, so that the volume of the optical attenuator is reduced.

[0031] The reflecting mirror 108 is fixed on a rotating device 109, in the embodiment, the rotating device 109 comprises a micro-electro-mechanical device and a metal base, the micro-electro-mechanical device is fixed on the metal base by an adhesive. The reflecting mirror 108 can be fixed on the micro-electro-mechanical device, when the micro-electro-mechanical device rotates, the reflecting mirror 108 can rotate, so that the inclination angle of the reflecting mirror 108 changes. In addition, the metal base has a plurality of pins, and the pads on the micro-electro-mechanical device are bonded to the plurality of pins by gold wires.

[0032] From Figure 1 As can be seen, the incident light signal L101 is incident into the incident fiber 111, when the light signal L101 is incident into the birefringent crystal 102, the light signal L101 will be divided into two polarized lights with perpendicular polarization directions, i.e. the light signal L102 and the light signal L103 are formed, the light signal L102 and the light signal L103 are ordinary light and extraordinary light respectively. Because the propagation paths of the ordinary light and the extraordinary light in the birefringent crystal are different, the two light signals L102 and L103 are not incident at the same position of the birefringent crystal 102.

[0033] The two light signals L102 and L103 are incident into the half-wave plate 115, the polarization directions of the two light signals L102 and L103 are rotated by 45°. When the two light signals L102 and L103 are incident into the rotating device 103, the polarization directions of the two light beams are rotated again, then the two light signals L102 and L103 are incident into the focusing lens 105 and form the light signals L104 and L105, under the action of the focusing lens, the light signals L104 and L105 are incident into the reflecting mirror 108. In the initial state, the reflecting surface of the reflecting mirror 108 is perpendicular to the axis of the focusing lens, the reflected light signals L106 and L107 are incident into the focusing lens 105 again, and then the two light signals L106 and L107 are incident into the rotating device 103 again, the polarization directions of the two light signals L106 and L107 are rotated again. At this time, compared with the light signals L102 and L103 obtained by dividing the light signal L101, the polarization directions of the light signals L106 and L107 are rotated by 90° after passing through the half-wave plate 115 and the rotating device 103 twice, that is, the ordinary light and the extraordinary light are exchanged. Because the reflected light signals L106 and L107 will not pass through the half-wave plate again, but are directly incident into the birefringent crystal 102, the two light signals L106 and L107 with perpendicular polarization directions will be combined in the birefringent crystal 102, form the light signal L108 and are incident into the exit fiber 112 of the double-core tail fiber 101, and are emitted from the exit fiber 112.

[0034] Different electrical signals are applied to the rotating device 109 to drive the micro-electro-mechanical device to rotate, thus driving the reflecting mirror 108 to rotate, and changing the direction of the reflected light signal, so that the optical power of the light signal coupled to the outgoing fiber 112 is reduced, thus realizing the adjustment of the attenuation amount of the light signal.

[0035] Referring to Figure 2 When the light signal L111 is incident from the outgoing fiber 112, it will be divided into two light signals L112 and L113 with mutually perpendicular polarization directions when passing through the birefringent crystal 102, but the polarization directions of the two light signals L112 and L113 will be rotated because the two light signals L112 and L113 will not pass through the half-wave plate but directly incident into the rotating device 103. Subsequently, the two light signals L112 and L113 are incident into the focusing lens 105 and form light signals L114 and L115, respectively, and are incident into the reflecting mirror 108.

[0036] After being reflected by the reflecting mirror 108, light signals L116 and L117 are formed, and are incident into the focusing lens 105 and again into the rotating device 103, and then into the half-wave plate 115 and form light signals L118 and L119, respectively. Because the polarization directions of the light signals are rotated by 45° after passing through the rotating device 103 twice, but the polarization directions are rotated by 45° again after passing through the half-wave plate 115, but the rotation direction is different from the forward light path, resulting in that the normal light and the abnormal light are not exchanged, the two light beams L118 and L119 pass through the birefringent crystal 102 in different directions due to the different light paths of the normal light and the abnormal light, and cannot be combined, so they will not be incident into the incident fiber 111. Therefore, the light signal incident from the outgoing fiber 112 cannot be finally emitted from the incident fiber 111, thereby avoiding the interference of the light signal incident in the opposite direction to the input light signal, and realizing the function of optical isolation.

[0037] In this embodiment, because the focusing lens 105 adopts a common spherical lens, that is, a C-lens, the focal point of the focusing lens 105 is far away from the second end surface 107 of the focusing lens, and therefore the reflecting mirror 108 can be arranged at a position far away from the focusing lens 105, so that the focusing lens 105 and the rotating device 109 are packaged separately, for example, the focusing lens 105 is packaged together with the rotating device 103 and the magnet 104, and the reflecting mirror 108 is packaged together with the rotating device 109, thereby avoiding the increase of the packaging difficulty caused by packaging the focusing lens 105, the reflecting mirror 108 and the rotating device 109 together, and reducing the production cost of the optical attenuator.

[0038] Second embodiment:

[0039] Referring to Figure 3The light attenuator with the isolation function has a double-core pigtail 201, and an incident optical fiber 211 and an emergent optical fiber 212 are arranged in the double-core pigtail 201, and the externally input optical signal can be incident to the incident optical fiber 211 and then be emitted from the emergent optical fiber 212 after being attenuated.

[0040] A birefringent crystal 202 is arranged at the emergent end of the double-core pigtail 201, and the birefringent crystal 202 covers two light paths of the double-core pigtail 201, and when the optical signal passes through the birefringent crystal 202, the optical signal can be divided into two polarized lights with perpendicular polarization directions, that is, normal light and abnormal light. A half-wave plate 203 is arranged at the end of the birefringent crystal 202 away from the double-core pigtail, and the half-wave plate 203 of the embodiment is arranged on only one light path of the birefringent crystal 202.

[0041] A rotating device 204 is arranged at the side of the half-wave plate 203 away from the birefringent crystal 202, and the rotating device 204 of the embodiment is a rotating device with a magnetic field intensity, so that a magnet does not need to be arranged outside the rotating device 204. In addition, the rotating device 204 covers two light paths of the birefringent crystal 202. In addition, the rotating angle of the rotating device 204 is 22.5°.

[0042] A focusing lens 205 is arranged at the side of the rotating device 204 away from the half-wave plate 203, and the focusing lens 205 of the embodiment is a self-focusing lens. The first end face 206 of the focusing lens 205 close to the rotating device 204 is a plane, and the second end face 207 of the focusing lens 205 away from the rotating device 204 is also a plane. In addition, the rotating device 204 is fixed on the first end face 206 through an adhesive.

[0043] A reflecting mirror 208 is arranged at the side of the focusing lens 205 away from the rotating device 204, and the reflecting mirror 208 is fixed on a rotating device 209. In the embodiment, the rotating device 209 includes a micro-electro-mechanical device and a metal base, and the micro-electro-mechanical device is fixed on the metal base through an adhesive. The reflecting mirror 208 can be fixed on the micro-electro-mechanical device, and when the micro-electro-mechanical device rotates, the reflecting mirror 208 can be driven to rotate, so that the inclination angle of the reflecting mirror 208 changes. In addition, the metal base has a plurality of pins, and the pads on the micro-electro-mechanical device are bonded to the plurality of pins through gold wires.

[0044] The incident light signal L201 is incident into the incident fiber 211, and when the light signal L201 is incident into the birefringent crystal 202, it will be divided into two polarized lights with polarization directions perpendicular to each other, i.e. light signal L202 and light signal L203 are formed, which are normal light and abnormal light respectively. Since the propagation paths of the normal light and the abnormal light in the birefringent crystal are different, the two light signals L202 and L203 pass through the birefringent crystal 202 at different positions.

[0045] The two light signals L202 and L203 emitted from the birefringent crystal 202 pass through the half-wave plate 203, and the polarization directions of the two light signals L202 and L203 are rotated by 45°. When the two light signals L202 and L203 are incident into the rotating device 204, the polarization directions of the two light beams are rotated again, and then the two light signals L202 and L203 are incident into the focusing lens 205 and form light signals L204 and L205 respectively. Under the action of the focusing lens 205, the light signals L204 and L205 are incident into the mirror 208. The light signals L206 and L207 reflected by the mirror 208 are incident into the focusing lens 205 again, and after passing through the focusing lens 205, they pass through the rotating device 204 again, and the polarization directions of the two light signals L206 and L207 are rotated again. At this time, compared with the light signals L202 and L203 obtained by splitting from the birefringent crystal 202, the polarization directions of the light signals L206 and L207 after passing through the half-wave plate 203 and twice passing through the rotating device 204 are equivalent to being rotated by 90°, that is, the normal light and the abnormal light are exchanged. When the reflected light signals L206 and L207 are incident into the birefringent crystal 202, they will be combined in the birefringent crystal 202 to form a light signal L208 and are incident into the exit fiber 212 of the double-core tail fiber 201 and are emitted from the exit fiber 212.

[0046] Third embodiment:

[0047] Referring to Figure 4 The optical attenuator with isolation function of the embodiment has a double-core tail fiber 301, and an incident fiber 311 and an exit fiber 312 are arranged in the double-core tail fiber 301. The externally input light signal can be incident into the incident fiber 311 and emitted from the exit fiber 312 after attenuation.

[0048] The birefringent crystal 302 is arranged at the exit end of the double-core fiber 301 and covers two light paths of the double-core fiber 301. When the optical signal passes through the birefringent crystal 302, the optical signal can be divided into two polarized lights with perpendicular polarization directions, i.e., normal light and abnormal light. The half-wave plate 303 is arranged at the end of the birefringent crystal 302 away from the double-core fiber. In the embodiment, the half-wave plate 303 is arranged on only one light path of the birefringent crystal 302.

[0049] The rotating device 304 is arranged at the side of the half-wave plate 303 away from the birefringent crystal 302. In the embodiment, the rotating device 304 has a magnetic field intensity, and thus, a magnet is not needed outside the rotating device 304. In addition, the rotating device 304 covers only one light path of the birefringent crystal 302, and the rotating angle of the rotating device 304 is 45°.

[0050] The focusing lens 305 is arranged at the side of the rotating device 304 away from the half-wave plate 303. In the embodiment, the focusing lens 305 is a self-focusing lens. The first end surface 306 of the focusing lens 305 close to the rotating device 304 is a plane, and the second end surface 307 of the focusing lens 305 away from the rotating device 304 is also a plane. In addition, the rotating device 304 is fixed to the first end surface 306 by an adhesive.

[0051] The reflecting mirror 308 is arranged at the side of the focusing lens 305 away from the rotating device 304. The reflecting mirror 308 is fixed to the rotating device 309. In the embodiment, the rotating device 309 includes a micro-electro-mechanical device and a metal base. The micro-electro-mechanical device is fixed to the metal base by an adhesive. The reflecting mirror 308 can be fixed to the micro-electro-mechanical device. When the micro-electro-mechanical device rotates, the reflecting mirror 308 can also rotate, so that the inclination angle of the reflecting mirror 308 changes. In addition, the metal base has a plurality of pins, and the pads on the micro-electro-mechanical device are bonded to the pins by gold wires.

[0052] The incident optical signal L301 is incident into the incident fiber 311. When the optical signal L301 is incident into the birefringent crystal 302, the optical signal L301 can be divided into two polarized lights with perpendicular polarization directions, i.e., the optical signal L302 and the optical signal L303. The optical signal L302 and the optical signal L303 are normal light and abnormal light, respectively.

[0053] The two light signals L302, L303 emitted from the birefringent crystal 302 pass through the half-wave plate 303, and the polarization directions of the two light signals L302, L303 are rotated by 45°. The two light signals L302, L303 are incident on the focusing lens 305 and form light signals L304, L305, respectively. Under the action of the focusing lens 305, the light signals L304, L305 are incident on the mirror 308. The light signals L306, L307 reflected by the mirror 308 are incident on the focusing lens 305 again and pass through the focusing lens 305, and then pass through the rotating device 304, and the polarization directions of the two light signals L306, L307 are rotated again. At this time, compared with the light signals L302, L303 obtained by splitting from the birefringent crystal 302, the polarization directions of the light signals L306, L307 after passing through the half-wave plate 303 and the rotating device 304 are equivalent to being rotated by 90°, that is, the normal light and the abnormal light are exchanged. When the reflected light signals L306, L307 are incident on the birefringent crystal 302, the light signals L306, L307 are combined in the birefringent crystal 302 to form a light signal L308 and are incident on the exit optical fiber 312 of the double-core pigtail fiber 301, and finally are emitted from the exit optical fiber 312.

[0054] It can be seen that the optical attenuator can realize attenuation adjustment of the optical signal, has the optical isolation function, and the rotating device is fixed on the first end of the focusing lens through the adhesive, the focusing lens and the rotating device are packaged in a separate manner to reduce the packaging difficulty of the optical attenuator, so that the production cost of the optical attenuator is reduced.

[0055] Finally, it should be emphasized that the above is only the preferred embodiment of the utility model, and is not used to limit the utility model. For those skilled in the art, the utility model can have various changes and changes, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. An optical attenuator with isolation function, comprising a double-core pigtail, an incident optical fiber and an outgoing optical fiber are arranged in the double-core pigtail, and a birefringent crystal is arranged at the outgoing end of the double-core pigtail; characterized in that: a half-wave plate is arranged at the end of the birefringent crystal away from the double-core pigtail, and the half-wave plate is arranged only on one light path of the birefringent crystal; a rotating device, a focusing lens and a mirror are arranged in sequence on the side of the half-wave plate away from the birefringent crystal, the mirror is fixed on a rotating device, and the rotating device can drive the mirror to rotate to change the angle of the reflected light beam; wherein the first end face of the focusing lens close to the rotating device is a plane, and the rotating device is fixed on the first end face of the focusing lens through an adhesive; the rotating device and the focusing lens are packaged into a module, and the focusing lens and the mirror are separately arranged; the rotating device comprises a micro-electro-mechanical device, and the micro-electro-mechanical device is fixed on a metal base through an adhesive.

2. The optical attenuator with isolation function according to claim 1, characterized in that: the second end face of the focusing lens away from the rotating device is a curved surface.

3. The optical attenuator with isolation function according to claim 1, characterized in that: the focusing lens is a self-focusing lens, and the second end face of the focusing lens away from the rotating device is a plane.

4. The optical attenuator with isolation function according to any one of claims 1 to 3, characterized in that: a magnetic ring is arranged outside the rotating device.

5. The optical attenuator with isolation function according to any one of claims 1 to 3, characterized in that: the rotating device has a magnetic field strength by itself.

6. The optical attenuator with isolation function according to any one of claims 1 to 3, characterized in that: the rotating device covers both light paths of the focusing lens, and the optical rotation angle of the rotating device is 22.5°.

7. The optical attenuator with isolation function according to any one of claims 1 to 3, characterized in that: the rotating device covers only one light path of the focusing lens, and the optical rotation angle of the rotating device is 45°.

8. The optical attenuator with isolation function according to claim 1, characterized in that: the metal base has a plurality of pins, and the bonding pads on the micro-electro-mechanical device are bonded to the plurality of pins through gold wires.

9. The optical attenuator with isolation function according to any one of claims 1 to 3, characterized in that: the focusing lens and the rotating device are separately packaged.

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