CN212989708U - Wavelength division multiplexing device - Google Patents

Abstract

The application provides a wavelength division multiplexing device, which comprises a self-focusing lens, a lens and a filter plate, wherein the pitch of the self-focusing lens is one quarter or odd times of one quarter; the utility model discloses a lens, including self-focusing lens, filter, lens interval, filter one side is provided with self-focusing lens, the filter is kept away from self-focusing lens's opposite side is provided with lens, the filter with self-focusing lens glues the bonding through first light path, the filter with the lens interval is gapped, the refracting index that first light path glued is greater than the refracting index of air. Compared with the prior art, the scheme reduces the use of an antireflection film, reduces the processing difficulty and reduces the cost. And the optical path glue is used for bonding the accessories together, and the size of the whole wavelength division multiplexing device is further reduced because the optical path glue occupies small space. In addition, because the lens with leave the clearance between the filter, the kind of lens can have more choices for this scheme's suitable scene is abundanter.

Description

Wavelength division multiplexing device

Technical Field

The present invention relates to the field of optical communications, and in particular, to a wavelength division multiplexing device.

Background

When light passes through the interface of media with different refractive indexes, the light is reflected at the interface, so that the intensity of the light is reduced. In a wavelength division multiplexing device, reflection of an optical signal through interfaces of different components may not only reduce the intensity of the optical signal, but the reflected optical signal may also affect the normal transmission of the optical signal. Therefore, in the wavelength division multiplexing device, in order to reduce reflection, the prior art adopts a method of plating an antireflection film on the end face of the optical fiber pigtail, the filter, the lens and other accessories so as to reduce reflection at the interface, but the requirement on the precision of the plated antireflection film is higher when the reflectivity is reduced by the method, which results in high price of the wavelength division multiplexing device.

SUMMERY OF THE UTILITY MODEL

The application aims to provide a wavelength division multiplexing device to solve the technical problems that the wavelength division multiplexing device in the prior art is large in size and high in precision requirement.

In a first aspect, the present application provides a wavelength division multiplexing device, comprising a self-focusing lens, a lens, and a filter, wherein the pitch of the self-focusing lens is one quarter or an odd multiple of one quarter; the utility model discloses a lens, including self-focusing lens, filter, lens interval, filter one side is provided with self-focusing lens, the filter is kept away from self-focusing lens's opposite side is provided with lens, the filter with self-focusing lens glues the bonding through first light path, the filter with the lens interval is gapped, the refracting index that first light path glued is greater than the refracting index of air.

In the application, the refractive index of the first light path glue is greater than that of air, so that the relative refractive index of the filter plate and the first light path glue is less than that of the filter plate and the air, and the refraction phenomenon generated when an optical signal passes through the boundary of the filter plate is reduced; similarly, the relative refractive index of the self-focusing lens and the first optical path glue is smaller than that of the self-focusing lens and air, so that the reflection phenomenon of an optical signal when the optical signal passes through the boundary of the self-focusing lens is reduced. The cost can be reduced by using the optical path glue with high refractive index to replace part of the antireflection film, the precision requirement on the optical path glue is lower, the cost is further reduced, and the size of the whole wavelength division multiplexing device is further reduced because the optical path glue occupies small space and is used for bonding all accessories together. In addition, because the lens with leave the clearance between the filter, the kind of lens can have more choices for this scheme's suitable scene is abundanter.

With reference to the technical solution provided by the first aspect, in some possible implementations, the filter includes a substrate and a WDM film, and a relative refractive index between the substrate and the first optical path glue is smaller than a relative refractive index between the substrate and the air; the WDM film is plated on the end face of the substrate close to the self-focusing lens.

In the present application, the relative refractive index of the substrate and air is greater than the relative refractive index of the substrate and the first optical path paste, so that the refractive index of the optical signal at the interface between the first optical path paste and the substrate is reduced; the WDM film is used for reflecting optical signals with specific wavelengths, so that the optical signals needing to be reflected back cannot pass through the filter.

With reference to the technical solution provided by the first aspect, in some possible implementation manners, the filter further includes an antireflection film, and the antireflection film is plated on the end surface of the substrate close to the lens.

In the application, because the filter and the lens are separated by a gap, in order to reduce the refractive index of the optical signal when the optical signal passes through the end face of one side of the filter, an antireflection film is plated on one side of the substrate close to the lens, so that the refractive index of the optical signal at the position is reduced.

With reference to the technical solution provided by the first aspect, in some possible implementations, the lens is a self-focusing lens or a spherical lens.

In the application, the lens needs to focus the light beam with a very small incident angle into a parallel light output or focus the incident parallel light into a light output, so that the lens can select a self-focusing lens with a quarter or an odd quarter of a pitch; and because a gap is reserved between the lens and the filter, the light path glue can not influence the working mechanism of the spherical lens, and the lens can also be a spherical lens.

With reference to the technical solution provided by the first aspect, in some possible implementations, the lens is a self-focusing lens with a diameter of 1 mm.

In this application, the lens is a self-focusing lens with a diameter of 1 mm, so that the size of the wavelength division multiplexing device can be reduced as much as possible while ensuring that the incident light beam with a very small incident angle is focused into a parallel light output or the incident parallel light beam is focused into a light output.

With reference to the technical solution provided by the first aspect, in some possible implementation manners, an antireflection film is plated on an end surface of the lens close to the filter.

In the application, because the lens and the filter are spaced by a gap, in order to reduce the refractive index of the optical signal when the optical signal passes through the end face of one side of the lens, an antireflection film is plated on one side of the lens close to the substrate, so that the refractive index of the optical signal at the position is reduced.

With reference to the technical solution provided by the first aspect, in some possible implementations, the diameter of the self-focusing lens is 1 mm.

In the application, the self-focusing lens adopts the self-focusing lens with the diameter of 1 mm, and the small-sized self-focusing lens has a better light gathering effect, so that light passing through the optical filter plate is effectively focused, and light loss is avoided as far as possible; in addition, the small size of the self-focusing lens can reduce the size of the wavelength division multiplexing device.

With reference to the technical solution provided by the first aspect, in some possible implementation manners, the wavelength division multiplexing device further includes a first fiber pigtail and a second fiber pigtail, a connector of the first fiber pigtail is bonded to the self-focusing lens through a second optical path glue, and a relative refractive index between the connector of the first fiber pigtail and the second optical path glue is smaller than a relative refractive index between the connector of the first fiber pigtail and the air; the connector of second optic fibre tail optical fiber with lens bond through third light path glue, the connector of second optic fibre tail optical fiber with the relative refractive index that third light path glued is less than the connector of second optic fibre tail optical fiber with the relative refractive index of air.

In the application, the relative refractive index between the connector of the first optical fiber pigtail and the second optical path glue is smaller than the relative refractive index between the connector of the first optical fiber pigtail and the air, so that the reflection of an optical signal when passing through the interface between the connector of the first optical fiber pigtail and the second optical path glue can be reduced; the connector of second optic fibre tail optical fiber with the relative refractive index that third light path glued is less than the connector of second optic fibre tail optical fiber with the relative refractive index of air consequently can reduce the light signal and pass through the connector of second optic fibre tail optical fiber with the reflection of the interfacial surface that third light path glued.

In combination with the technical solution provided by the first aspect, in some possible implementation manners, the wavelength division multiplexing device further includes a sealing fixing tube, the filter, the self-focusing lens, the bonding position between the self-focusing lens and the first fiber pigtail, and the bonding position between the lens and the second fiber pigtail are disposed in the sealing fixing tube, and the first fiber pigtail and the second fiber pigtail are fixed by a fourth optical path adhesive.

In this application, sealed fixed pipe is used for the protection the filter plate self-focusing lens with the bonding department of first optic fibre tail optical fiber lens with the bonding department of second optic fibre tail optical fiber, simultaneously, glue the relative position of fixed each accessory through the fourth light path to prevent that external factors from gluing first light path, the gluey influence of second light path, third light path, thereby lead to the light path to glue the variability, influence wavelength division multiplexing device's performance. In addition, in this application, can realize the fixed of each accessory with a sealed fixed pipe, compare in the scheme that uses 3 sealed fixed pipes among the prior art, simple structure to can further reduce wavelength division multiplexing device's size.

With reference to the technical solution provided by the first aspect, in some possible implementation manners, the sealing and fixing tube is a glass tube, and an outer diameter of the glass tube is 3 mm.

In this application, the sealed fixed pipe uses the glass pipe can increase the optical path and glue the optional scope, and the optical path glues and can use the photocuring to glue promptly. In addition, since no other fixing tube is provided between the seal fixing tube and the internal fitting, a glass tube having a small size, for example, an outer diameter of 3 mm, can be selected as the seal fixing tube, and the size of the wavelength division multiplexing device can be further reduced while securing the fixing effect.

Drawings

Fig. 1 is a schematic structural diagram of a wavelength division multiplexing device according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of a filter according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of another wavelength division multiplexing device provided in an embodiment of the present application;

fig. 4 is a schematic diagram of a propagation path of an optical signal in a partial structure of a wavelength division multiplexing device according to an embodiment of the present application;

fig. 5 is a schematic diagram of a propagation path of an optical signal in a partial structure of a wavelength division multiplexing device according to an embodiment of the present application;

fig. 6 is a schematic diagram of a propagation path of an optical signal in a partial structure of a wavelength division multiplexing device according to an embodiment of the present application.

Icon: 1-wavelength division multiplexing device, 10-filter, 100-substrate, 101-WDM film, 102-antireflection film, 11-self-focusing lens, 12-lens, 121-antireflection film, 13-first optical fiber pigtail, 14-second optical fiber pigtail, 15-sealing fixed tube, 16-first optical path glue, 161-second optical path glue and 162-third optical path glue.

Detailed Description

The terms "first," "second," "third," and the like are used for descriptive purposes only and not for purposes of indicating or implying relative importance, and do not denote any order or order.

Furthermore, the terms "horizontal", "vertical", "overhang" and the like do not imply that the components are required to be absolutely horizontal or overhang, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present application, it should be noted that the terms "inside", "outside", "left", "right", "upper", "lower", and the like indicate orientations or positional relationships based on orientations or positional relationships shown in the drawings or orientations or positional relationships that are conventionally arranged when products of the application are used, and are used only for convenience in describing the application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the application.

In the description of the present application, unless expressly stated or limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements.

Please refer to fig. 1, which is a wavelength division multiplexing device according to an embodiment of the present application. The wavelength division multiplexing device 1 includes a filter 10, a self-focusing lens 11, and a lens 12. The pitch of the self-focusing lens is a quarter or an odd multiple of a quarter. Filter 10 one end is provided with self-focusing lens 11, and the one end that filter 10 kept away from self-focusing lens 11 is provided with lens 12, and filter 10 glues 16 bonding through first light path with self-focusing lens 11, and filter 10 and lens 12 interval are gapped, and the refracting index that 16 was glued to first light path is greater than the refracting index of air.

Referring to fig. 1, in one embodiment of the self-focusing lens 11, the pitch of the self-focusing lens 11 is one fourth, and the one fourth pitch self-focusing lens 11 can focus the light beam incident at a very small incident angle into a parallel light output or focus the incident parallel light into a light output.

Alternatively, the pitch of the self-focusing lens 11 is three-quarters, and the self-focusing lens 11 with three-quarters pitch can also focus the light beam incident at a very small incident angle into a parallel light output, or focus the incident parallel light into a light output.

Optionally, the small-sized self-focusing lens 11 is a small-sized self-focusing lens, for example, a self-focusing lens with a diameter of 1 mm, and the small-sized self-focusing lens has a better light gathering effect, so that light passing through the optical filter is effectively focused, and light loss is not generated as much as possible; in addition, the small size of the self-focusing lens can reduce the size of the wavelength division multiplexing device.

With continued reference to fig. 1, one embodiment of the lens 12 is that the lens 12 is a quarter-pitch self-focusing lens, which can focus the incident light beam with a very small incident angle into a parallel light output or focus the incident parallel light into a light output.

Optionally, the lens 12 is a three-quarter pitch self-focusing lens, and the three-quarter pitch self-focusing lens can also focus a light beam incident at a very small incident angle into a parallel light output, or focus the incident parallel light into a light output.

Alternatively, in order to reduce the size of the wavelength division multiplexing device 1, the lens 11 may be a small-sized self-focusing lens, for example, a self-focusing lens having a diameter of 1 mm.

Referring to fig. 3, another wavelength division multiplexing device provided in the present application, compared to the wavelength division multiplexing device shown in fig. 1, the lens 12 of the wavelength division multiplexing device is a spherical lens, which can focus a light beam incident at a very small incident angle into a parallel light output, or focus the incident parallel light into a light output.

Referring to fig. 1 and 2, an embodiment of the filter 10 is that the filter 10 includes a substrate 100, a WDM film 101, and an antireflection film 102, a relative refractive index between the substrate 100 and the first optical path glue 16 is much smaller than a relative refractive index between the substrate 100 and air, the WDM film 101 is plated on an end surface of the substrate 100 connected to the first optical path glue 16, and the antireflection film 102 is plated on an end surface of the substrate 100 near the lens 12.

In this application, when an optical signal passes through the filter 10, the WDM film 101 reflects back an optical signal of a specific wavelength; the antireflection film 102 reduces or eliminates the reflected light from the surface of the substrate 100, thereby increasing the amount of light transmission of the filter 10.

Optionally, in order to reduce the refraction of the optical signal at the interface between the substrate 100 and the first optical path paste 16, the substrate 100 is implemented by using a sapphire substrate with a high refractive index as the substrate 100. According to the embodiment of the application, the filter plate 10 and the self-focusing lens 11 are bonded by the first light path glue 16 with high refractive index, and the refractive index of the sapphire substrate with high refractive index is close to that of the first light path glue 16, so that the relative refractive index of the substrate 100 and the first light path glue 16 is small, and the refraction of an optical signal on the interface between the first light path glue 16 and the filter plate 10 is reduced.

Referring to fig. 1, the wavelength division multiplexing device 1 further includes a first fiber pigtail 13, in an embodiment of the first fiber pigtail 13, the first fiber pigtail 13 is a single fiber pigtail, the first fiber pigtail 13 is bonded to the self-focusing lens 11 by a second optical path glue 161, and a refractive index of the second optical path glue 161 is close to a refractive index of the connector of the first fiber pigtail 13.

Alternatively, the first fiber pigtail 13 may be another type of fiber pigtail, such as a dual fiber pigtail, a triple fiber pigtail, or the like.

Optionally, in order to prevent the light reflected at the bonding position of the self-focusing lens 11 and the first fiber pigtail 13 from affecting the optical signal transmitted in the first fiber pigtail, an embodiment of the self-focusing lens 11 and the first fiber pigtail 13 is that the interface between the self-focusing lens 11 and the first fiber pigtail 13 is an inclined plane having an inclination angle of 8 ° with respect to the vertical plane, and due to the inclination angle of 8 °, the light reflected at the inclined plane is not reflected back along the incident optical path, that is, the reflected light does not enter the fiber of the first fiber pigtail 13.

Referring to fig. 1, the wavelength division multiplexing device 1 further includes a second fiber pigtail 14, in an embodiment of the second fiber pigtail 14, the second fiber pigtail 14 is a dual-fiber pigtail, the second fiber pigtail 14 is bonded to the lens 12 by a third optical path glue 162, and a refractive index of the third optical path glue 162 is close to a refractive index of the connector of the second fiber pigtail 14.

Alternatively, the second fiber pigtail 14 may be other types of fiber pigtails, such as a dual fiber pigtail, a triple fiber pigtail, or the like.

Optionally, in order to prevent the light reflected at the bonding position of the lens 12 and the second fiber pigtail 14 from affecting the optical signal transmitted in the second fiber pigtail 14, an embodiment of the lens 12 and the second fiber pigtail 14 is that the interface between the lens 12 and the second fiber pigtail 14 is an inclined plane having an inclination angle of 8 ° with respect to the vertical plane, and due to the inclination angle of 8 °, the light reflected at the inclined plane is not reflected back along the incident optical path, that is, the reflected light does not enter the fiber of the second fiber pigtail 14.

Referring to fig. 1, the wavelength division multiplexing device 1 further includes a sealing fixing tube 15 to prevent the first optical path glue 16, the second optical path glue 161, and the third optical path glue 162 from being denatured, and simultaneously fix the first fiber pigtail 13 and the second fiber pigtail 14 through the fourth optical path glue 163, so as to keep the relative positions of the first fiber pigtail 13 and the second fiber pigtail 14 unchanged.

Alternatively, since no other fixing tube is provided between the seal fixing tube 15 and the inner fitting, a small size can be selected, and therefore, an embodiment of the seal fixing tube 15 is such that the outer diameter of the seal fixing tube 15 is 3 mm.

Alternatively, the seal fixing tube 15 is a glass tube.

Alternatively, the sealing fixing tube 15 is a thin tube made of other materials, such as a metal tube, a plastic tube, and the like, and specific parameters such as the length and the outer diameter of the sealing fixing tube 15 are not limited to specific values.

Optionally, the first optical path glue 16, the second optical path glue 161, the third optical path glue 162, and the fourth optical path glue 163 may be the same optical path glue, or the first optical path glue 16, the second optical path glue 161, the third optical path glue 162, and the fourth optical path glue 163 may be different kinds of optical path glues.

Optionally, the first light path glue 16, the second light path glue 161, the third light path glue 162, and the fourth light path glue 163 may be glues with high refractive index and good light transmittance, such as UV glue and FA tail glue.

With the above scheme, one case of the optical signal being conducted in the wavelength division multiplexing device is shown in fig. 4, 5, and 6.

Referring to fig. 4, in this embodiment, the first fiber pigtail 13 is a dual fiber pigtail, and one of the fibers of the first fiber pigtail 13 transmits an optical signal, and the optical signal enters the self-focusing lens 11 from the first fiber pigtail 13 through the second optical path glue 161, because the refractive index of the second optical path glue 161 is close to the refractive index of the first fiber pigtail 13, the reflectivity of the optical signal is greatly reduced when the optical signal passes through the interface between the second optical path glue 161 and the first fiber pigtail 13, and there is a certain included angle between the interface between the first fiber pigtail 13 and the self-focusing lens 11 and the vertical plane, that is, the incident angle of the optical signal is not a right angle, so that the optical signal reflected at the interface between the first fiber pigtail 13 and the second optical path glue 161 does not enter any fiber of the first fiber pigtail 13, and does not affect the normally transmitted optical signal.

Referring to fig. 4, after entering the second optical path glue 161, the optical signal enters the self-focusing lens 11 through the interface between the second optical path glue 161 and the self-focusing lens 11, the refractive index of the second optical path glue 161 is greater than that of air, and the relative refractive index between the second optical path glue 161 and the self-focusing lens 11 is much smaller than that between the self-focusing lens 11 and air, so that the reflectivity of the optical signal is greatly reduced when the optical signal passes through the interface between the second optical path glue 161 and the self-focusing lens 11, and the interface between the first fiber pigtail 13 and the self-focusing lens 11 forms a certain angle with the vertical plane, so that the interface between the second optical path glue 161 and the self-focusing lens 11 also forms an angle with the vertical plane, that is, the optical signal is not vertically incident into the self-focusing lens 11, and therefore the optical signal reflected at the interface between the self-focusing lens 11 and the second optical path glue 161 does not enter any fiber of the first fiber pigtail 13, the normally transmitted optical signal is not affected. Under the action of the second self-focusing lens 12, the incident optical signal is split into two or more parallel optical signals.

Referring to fig. 5, after entering the self-focusing lens 11, the optical signal is separated into two optical signals, the two optical signals are parallel at an end surface of the self-focusing lens 11 adjacent to the filter 10, the two parallel optical signals enter the first optical path glue 16 through an interface between the first optical path glue 16 and the self-focusing lens 11, a refractive index of the first optical path glue 16 is greater than that of air, and a relative refractive index between the first optical path glue 16 and the self-focusing lens 11 is much smaller than that between the self-focusing lens 11 and the air, so that a reflectivity of the optical signal is greatly reduced when the optical signal passes through an interface between the first optical path glue 16 and the self-focusing lens 11.

Referring to fig. 5, since the filter 10 is plated with the WDM film on the end surface near the self-focusing lens 11, when two parallel optical signals pass through the interface between the first optical path glue 16 and the filter 10, the optical signal with a specific wavelength is reflected back, returns to the first optical fiber pigtail 13 through the first optical path glue 16, the self-focusing lens 11, and the second optical path glue 161, and is transmitted through the other optical fiber of the first optical fiber pigtail 13, and the rest of the optical signals enter the filter 10.

Referring to fig. 6, when two parallel optical signals pass through the interface between the filter 10 and the air, the end surface of the filter 10 contacting the air is plated with an antireflection film, which can reduce or eliminate the reflected light of the optical mirrors such as lenses and prisms, so that the reflectivity of the optical signals is greatly reduced when the optical signals pass through the interface.

Referring to fig. 6, after two parallel optical signals are transmitted in the air for a distance, they enter the lens 12 through the interface between the air and the lens 12, and since the end surface of the lens 12 contacting the air is plated with the antireflection film 121, and the antireflection film 121 can reduce or eliminate the reflected light of the optical mirror surfaces such as the lens and the prism, the reflectivity of the optical signals is greatly reduced when the optical signals pass through the interface.

Referring to fig. 6, in the present embodiment, the lens 12 is a self-focusing lens, when two parallel optical signals are incident into the lens 12, the two parallel optical signals are coupled into one optical signal to be emitted under the action of the lens 12, and the emitted optical signal passes through the interface between the lens 12 and the third optical path glue 162, because the relative refractive index between the third optical path glue 162 and the lens 12 is much smaller than the refractive index between the lens 12 and the air, the reflectivity of the optical signal is greatly reduced when the optical signal passes through the interface between the lens 12 and the third optical path glue 161.

Referring to fig. 6, when the optical signal is incident into the second fiber pigtail 14 from the third optical path glue 162, since the refractive index of the third optical path glue 162 is close to the refractive index of the second fiber pigtail, the relative refractive index of the third optical path glue 162 and the second fiber pigtail 14 is much smaller than the relative refractive index of the second fiber pigtail 14 and air, the reflection of the optical signal at the interface between the third optical path glue 162 and the second fiber pigtail 14 is greatly reduced, and the optical signal is incident into the second fiber pigtail 14.

To sum up, the wavelength division multiplexing device that this application embodiment provided only needs plate antireflection coating at the terminal surface that filter 10 is close to lens 12 and the terminal surface that lens 12 is close to filter 10, and leave the clearance between lens 12 and filter 10, therefore lens 12's kind can have more selections, make this scheme's suitable scene abundanter, remaining part can all use the optical path to glue and replace antireflection coating, the cost is reduced, and the required precision that glues the optical path is very low, can further reduce cost, most accessories all link together through the optical path is glued in addition, the optical path glues the shared space very little, so whole wavelength division multiplexing device's size has been reduced.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (10)

1. A wavelength division multiplexing device, comprising:

a self-focusing lens having a pitch of one quarter or an odd multiple of one quarter;

a lens;

the filter, filter one side is provided with self-focusing lens, the filter is kept away from self-focusing lens's opposite side is provided with lens, the filter with self-focusing lens glues the bonding through first light path, the filter with the lens interval is gapped, the refracting index that first light path glued is greater than the refracting index of air.

2. The wavelength division multiplexing device of claim 1, wherein the filter segment comprises:

the relative refractive index of the substrate and the first light path glue is smaller than that of the substrate and the air;

a WDM film plated on an end face of the substrate near the self-focusing lens.

3. The wavelength division multiplexing device of claim 2, wherein the filter further comprises:

and the antireflection film is plated on the end face, close to the lens, of the substrate.

4. The wdm device of claim 1, wherein the lens is a self-focusing lens or a spherical lens.

5. The WDM device according to claim 4, wherein the lens is a 1 mm diameter self-focusing lens.

6. The WDM device according to claim 1, wherein the end surface of the lens near the filter is coated with an antireflection film.

7. The wdm device of claim 1, wherein the self-focusing lens is 1 mm in diameter.

8. The wavelength division multiplexing device of claim 1, wherein the wavelength division multiplexing device further comprises:

the connector of the first optical fiber pigtail is bonded with the self-focusing lens through second optical path glue, and the relative refractive index of the connector of the first optical fiber pigtail and the second optical path glue is smaller than that of the connector of the first optical fiber pigtail and the air;

the second optic fibre tail optical fiber, the connector of second optic fibre tail optical fiber with lens bond through third light path glue, the connector of second optic fibre tail optical fiber with the relative refractive index that third light path glued is less than the connector of second optic fibre tail optical fiber with the relative refractive index of air.

9. The wavelength division multiplexing device of claim 8, wherein the wavelength division multiplexing device further comprises:

the filter plate, the self-focusing lens with the bonding department of first optic fibre tail optical fiber lens with the bonding department of second optic fibre tail optical fiber set up in the sealed fixed tube, it is fixed through fourth light path glue first optic fibre tail optical fiber the second optic fibre tail optical fiber.

10. The wdm device of claim 9, wherein the hermetic fixation tube is a glass tube having an outer diameter of 3 mm.

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