1. An adjustable optical filter comprises a double-core optical fiber collimator, a first prism, a transmission type grating, a second prism and an adjustable reflector which are sequentially arranged from front to back; the dual-core optical fiber collimator and the adjustable reflector are arranged along the axis of the adjustable optical filter;

the dual-core optical fiber collimator is used for collimating an optical signal input by an input tail fiber and outputting a collimated beam advancing along the axis;

the first prism is used for deflecting the collimated light beam into a light beam forming a first included angle with the axis;

the transmission type grating is used for splitting the light beam output by the first prism;

the second prism is used for deflecting the light beam output by the transmission type grating to continue to advance along the axis;

the adjustable reflector is used for reflecting the light beam output forward by the second prism, returning the light beam back to the double-core optical fiber collimator and outputting the light beam outwards through an output tail fiber of the double-core optical fiber collimator; when the adjustable filter is in work, the reflection angle of the adjustable reflector can be adjusted, so that light beams with different wavelengths are output, and the adjustable filter function is realized.

2. A tunable optical filter according to claim 1, wherein the dual-core fiber collimator, the first prism, the transmissive grating, the second prism, and the tunable mirror are all arranged on the axis.

3. A tunable optical filter according to claim 1, wherein the surface of the first prism facing the transmissive grating and the surface of the second prism facing the transmissive grating are both perpendicular to the axis.

4. A tunable optical filter according to claim 1, wherein the cross-section of the first prism and the cross-section of the second prism are both isosceles triangles.

5. A tunable optical filter according to claim 4, wherein the apex angle of the first prism is on the same side of the axis as the apex angle of the second prism.

6. A tunable optical filter according to claim 2, wherein the tunable optical filter is linear, the axis is a straight line extending straight, and the first angle is between 43 degrees and 51 degrees.

7. A tunable optical filter according to any one of claims 1 to 6, wherein the dual core fiber collimator is mounted in a first package tube, the first prism, the transmission grating and the second prism are housed in a second package tube, and one end of the second package tube is attached to the first package tube and the tunable mirror is attached to the other end of the second package tube.

8. A tunable optical filter according to claim 7, wherein the second package tube is an eccentric glass tube.

9. A tunable optical filter according to claim 7, further comprising a carrier plate, wherein one side of the carrier plate is fixed to the second package tube, and the first prism, the transmissive grating and the second prism are fixed to the other side of the carrier plate.

10. A tunable optical filter according to any one of claims 1 to 6, wherein the tunable mirror is disposed on a base, and the tunable mirror is a micro-electromechanical mirror.

Background

A conventional tunable filter is shown in CN202182973U, and includes a signal input end, a signal output end, a focusing element, and a grating, and an input collimator, an output collimator, a first grating, a first mirror, a beam expanding element, a second grating, and a second mirror are disposed along an optical path. The first reflector is a rotatable reflector, and wavelength selection is realized by changing the incidence angles of the first grating and the second grating through the rotatable reflector. The tunable filter has complicated components and a bent optical path, thereby causing inconvenience in manufacturing and assembling.

Disclosure of Invention

In order to solve the technical problem, the application provides an adjustable optical filter which is simple in structure and convenient to adjust and assemble.

An adjustable optical filter comprises a double-core optical fiber collimator, a first prism, a transmission type grating, a second prism and an adjustable reflector which are sequentially arranged from front to back; the double-core optical fiber collimator and the adjustable reflector are arranged along the axis of the adjustable optical filter;

the dual-core optical fiber collimator is used for collimating an optical signal input by an input tail fiber and outputting a collimated beam advancing along the axis;

the first prism is used for deflecting the collimated light beam into a light beam forming a first included angle with the axis;

the transmission type grating is used for splitting the light beam output by the first prism;

the second prism is used for deflecting the light beam output by the transmission type grating to continue to advance along the axis;

the adjustable reflector is used for reflecting the light beam output forward by the second prism, returning the light beam back to the double-core optical fiber collimator and outputting the light beam outwards through an output tail fiber of the double-core optical fiber collimator; when the adjustable filter is in work, the reflection angle of the adjustable reflector can be adjusted, so that light beams with different wavelengths are output, and the adjustable filter function is realized.

In one embodiment, the dual-core fiber collimator, the first prism, the transmissive grating, the second prism, and the tunable mirror are all arranged on the axis.

In one embodiment, a surface of the first prism facing the transmission grating and a surface of the second prism facing the transmission grating are perpendicular to the axis.

In one embodiment, the cross section of the first prism and the cross section of the second prism are both isosceles triangles.

In one embodiment, the apex angle of the first prism is on the same side of the axis as the apex angle of the second prism.

In one embodiment, the tunable optical filter is linear, the axis is a straight line extending straight, and the first included angle is between 43 degrees and 51 degrees.

In one embodiment, the dual-core fiber collimator is installed in a first package tube, the first prism, the transmission grating and the second prism are contained in a second package tube, one end of the second package tube is attached to the first package tube, and the adjustable mirror is attached to the other end of the second package tube.

In one embodiment, the second enclosure tube is an eccentric glass tube.

In one embodiment, the optical device further includes a carrier plate, one side surface of the carrier plate is fixed to the second package tube, and the first prism, the transmissive grating and the second prism are fixed to the other side surface of the carrier plate.

In one embodiment, the adjustable mirror is disposed on a base, and the adjustable mirror is a micro-electromechanical mirror.

According to the technical scheme, the method has at least the following advantages and positive effects:

the application provides an adjustable optical filter, and the component of this kind of adjustable optical filter is comparatively simple to two core fiber collimator and adjustable speculum are all arranged along adjustable optical filter's axis, are the linear type design, have small, make the advantage of adjusting easily.

Drawings

FIG. 1 is a perspective view of a tunable optical filter according to a preferred embodiment of the present application;

FIG. 2 is a cross-sectional view of the tunable optical filter according to FIG. 1;

FIG. 3 is an optical diagram of the tunable optical filter according to FIG. 1;

FIG. 4 is a cross-sectional view from another angle of the tunable optical filter shown in FIG. 1;

fig. 5 is a schematic optical path diagram of another angle of the tunable optical filter shown in fig. 1.

The reference numerals are explained below: 10. a tunable optical filter; 11. a dual-core fiber collimator; 111. inputting tail fibers; 112. outputting tail fibers; 113. a double-bore tube; 114. a collimating lens; 12. a first prism; 121. an incident surface; 122. a first surface; 13. a transmissive grating; 14. a second prism; 141. a second surface; 15. an adjustable mirror assembly; 151. an adjustable mirror; 152. a base; 153. a third encapsulation tube; 16. a first encapsulation tube; 17. a second encapsulation tube; 18. a carrier plate; 21. 22, 23, 24, light beam.

Detailed Description

Exemplary embodiments that embody features and advantages of the present application will be described in detail in the following description. It is to be understood that the present application is capable of various modifications in various embodiments without departing from the scope of the application, and that the description and drawings are to be taken as illustrative and not restrictive in character.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated in a particular manner, and are not to be construed as limiting the present application. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

In the description of the present application, it is to be noted that the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected unless otherwise explicitly stated or limited. Either mechanically or electrically. Either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

Referring to fig. 1 and 2, a preferred embodiment of the present application provides a tunable optical filter. The tunable optical filter 10 includes a dual-core fiber collimator 11, a first prism 12, a transmissive grating 13, a second prism 14, and a tunable mirror 151 sequentially disposed in front and behind. The input optical signal enters the dual-core optical fiber collimator 11 to become a collimated beam, is deflected by the first prism 12, is dispersed and split by the transmission grating 13, is deflected by the second prism 14, and enters the adjustable reflector 151, and only the optical signal meeting the reflection angle condition of the adjustable reflector 151 can return to the dual-core optical fiber collimator 11 along the original path.

In the tunable optical filter 10, the dual-core fiber collimator 11 and the tunable mirror are both disposed along the axis L of the tunable optical filter 10. The optical axis of the dual-core fiber collimator 11, the optical axis of the transmission grating 13, and the optical axis of the tunable mirror 151 are coincident or parallel to each other, and the tunable optical filter 10 has a linear external shape. Compared with the conventional tunable optical filter, the tunable optical filter 10 of the present embodiment has the advantages that each optical element is arranged along the axis L of the tunable optical filter, and is linearly distributed, so that the size is small and the assembly and debugging are convenient. It should be noted that the optical elements arranged along the axis L in the present application do not mean that the optical elements are symmetrically distributed up and down along the axis L, but mean that the optical elements are substantially arranged on the axis L, but the optical elements may be shifted up or down by a small distance perpendicular to the axis L according to actual needs.

Specifically, in the present embodiment, the dual-core fiber collimator 11 includes an input pigtail 111, an output pigtail 112, a dual-hole tube 113, and a collimating lens 114. Where the input pigtail 111 is used to input optical signals having a plurality of different wavelengths. Output pigtail 112 is used to output optical signals having the desired wavelength. A double bore tube 113 is used to secure the input pigtail 111 and the output pigtail 112. Wherein the end faces of the input pigtail 111 and the output pigtail 112 are preferably located in the front focal plane of the collimating lens 114, the losses of the whole optical system will be minimized.

The dual-core fiber collimator 11 is used for collimating the optical signal input from the input pigtail 111 and outputting a collimated beam 21 advancing along the axis L. It should be noted that the collimated light beam 21 in the preferred embodiment is illustrated as proceeding parallel to the axis L, while in other possible embodiments the collimated light beam 21 may be at a small angle, such as within 3 degrees, to the axis L.

The dual-core fiber collimator 11 is preferably mounted within a first package tube 16. Specifically, collimating lens 114 is housed within first package tube 16. The front end of the double bore tube 113 is sealingly connected to the first enclosure tube 16. Wherein the first packaging tube 16 may be a glass tube or a plastic tube. The axis of the dual-core fiber collimator 11 and the axis of the first packing tube 16 are preferably located on the same straight line.

As shown in fig. 3, the first prism 12 is used for deflecting the advancing path of the collimated light beam 21, the collimated light beam 21 enters from the rear side of the first prism 12 and exits from the front side, so that the collimated light beam 21 advancing along the axis is deflected into a light beam 22 forming a first included angle b with the axis L, wherein the first included angle b is preferably 43 degrees to 51 degrees. The shape of the cross section of the first prism 12 is preferably an isosceles triangle. One side waist of the isosceles triangle is close to the dual-core fiber collimator 11, and the other side waist is close to the transmissive grating 13. The side waist near the dual-core fiber collimator 11 is the incident surface 121 of the first prism 12, and the other side waist near the transmissive grating 13 is the exit surface (first surface 122) of the first prism 12. The collimated light beam 21 is incident from the incident surface 121 and exits from the first surface 122, wherein the first surface 122 is preferably perpendicular to the axis L.

Referring to fig. 3, in the present embodiment, the collimated light beam 21 is parallel to the axis L of the tunable optical filter 10. Therefore, the size of the incident angle a of the collimated light beam 21 on the incident surface 121 is equal to the size of the apex angle of the first prism 12. The angle of incidence a of the collimated beam 21 is preferably between 45 and 55 degrees. Therefore, the size of the apex angle of the first prism 12 is also preferably set to be between 45 degrees and 55 degrees.

First prism 12 is preferably coated with an anti-reflective coating (not shown) to reduce the loss of light energy. The antireflection film can enhance the transmittance of light.

The transmissive grating 13 is used to split the light beam 22 output from the first prism 12. The light beam 22 is incident toward the transmission grating 13, and a light beam 23 is transmitted through the transmission grating 13. Wherein the light beam 23 has been split into a plurality of light beams of different wavelengths.

The shape of the cross section of the second prism 14 is preferably an isosceles triangle. The vertex angle of the second prism 14 and the vertex angle of the first prism 12 are preferably located on the same side of the axis L (the upper side of the axis L as viewed in fig. 3). Second prism 14 may also be coated with an anti-reflection coating to reduce the loss of light energy.

One side of the second prism 14 close to the transmissive grating 13 is a second surface 141, and the second surface 141 is perpendicular to the direction of the axis L. The light beam 23 passing through the transmissive grating 13 is incident on the second prism 14, and the incident light beam 23 is preferably incident on the second prism 14 at an incident angle of between 43 and 51 degrees. The second prism 14 deflects the beam 23 output by the transmission grating 13 into a beam 24 that continues to propagate forward along the axis L.

Since the second surface 141 is perpendicular to the direction of the axis L. The light beam 24 propagates parallel to the axis L. The size d of the exit angle of the light beam 24 is therefore equal to the size of the apex angle of the second prism 14. In the present embodiment, the size of the exit angle d of the light beam 24 is preferably between 61 degrees and 73 degrees, and the vertex angle of the second prism 14 is preferably between 61 degrees and 73 degrees.

Therefore, the light beam 21 passes through the first prism 12, the transmission grating 13, and the second prism 14 in this order, and the propagation direction of the light beam 21 is not substantially changed, but the exit position of the light beam 24 is changed, and the light beam 24 is dispersed. Therefore, the first prism 12, the transmissive grating 13 and the second prism 14 constitute a dispersion element.

The first prism 12, the transmissive grating 13 and the second prism 14 are preferably accommodated in a second packaging tube 17, thereby fixing the relative positions of the respective dispersion members.

Referring to fig. 4, the tunable optical filter preferably further includes a carrier 18. Wherein the first prism 12, the transmissive grating 13 and the second prism 14 are fixed on the upper side of the carrier 18. The lower side of the carrier plate 18 is fixed to the second packaging tube 17 to provide a stable mounting plane for the first prism 12, the transmissive grating 13 and the second prism 14, so that the first prism 12, the transmissive grating 13 and the second prism 14 can be integrally fixed to the carrier plate 18 during assembly, and then the carrier plate 18 is fixed to the second packaging tube 17 in a front-back positioning manner, thereby facilitating assembly and accurate alignment.

Both the first packing tube 16 and the second packing tube 17 extend in the axial direction L. Specifically, the second packaging tube 17 is preferably an eccentric glass tube, and when the optical axis position of the dispersive component needs to be adjusted during assembly, the relative position between the dispersive component and the collimating lens 114 can be conveniently adjusted by rotating the second packaging tube 17, so as to achieve the purpose of adjusting the optical axis position of the dispersive component.

The rear end of the first packing tube 16 is sealingly connected to the front end of the second packing tube 17. The diameter of the second packaging tube 17 is preferably larger than that of the first packaging tube 16, and the thickness of the second packaging tube 17 is also preferably larger than that of the first packaging tube 16, so that the rear end of the first packaging tube 16 can be closely and hermetically connected with the front end of the second packaging tube 17, and external dust is prevented from entering the second packaging tube 17.

The adjustable mirror assembly 15 is preferably a micro electro Mechanical mirror MEMS (micro electro Mechanical systems) including an adjustable mirror 151, a base 152 and a third packaging tube 153. The adjustable mirror 151 and the base 152 are hermetically installed in a third packaging tube 153.

The adjustable mirror 151 is provided on the base 152, and the propagation direction of the reflected light can be changed by adjusting the rotation angle of the adjustable mirror 151. Referring to fig. 5, the adjustable mirror 151 can rotate as shown in fig. 5, and accordingly, the reflection angle of the incident light can be changed, so that the light with a specific wavelength can be selected to be reflected, and the light returns to the output pigtail 112 through the second prism 14, the transmissive grating 13, the first prism 12 and the collimating lens 114, and is output to the outside through the output pigtail 112, thereby achieving the filtering function.

The base 152 of the adjustable mirror assembly 15 is horizontally aligned with the dispersion assembly and the third packing tube 153 is horizontally attached to the other end (i.e., the front end) of the second packing tube 17 remote from the first packing tube 16. The first, second, and third packing tubes 16, 17, 153 are coaxially and sequentially arranged in a step shape.

As shown in fig. 2 to 4, the dual-core fiber collimator 114, the first prism 12, the transmissive grating 13, the second prism 14 and the tunable mirror 151 are arranged substantially in a straight line on the axis L of the tunable optical filter 10, so that the tunable optical filter 10 may have a straight line shape, and the components are simpler and the implementation process is simpler. Moreover, the axis of the dual-core fiber collimator 11 is substantially aligned with the axis of the adjustable mirror 151, so that the adjustment dimension is small during angle adjustment, and adjustment is convenient.

Also, the dual-core fiber collimator 11 may be packaged in the first packaging tube 16 first. The dispersive component may also be encapsulated first in the second encapsulation tube 17. Therefore, the dual-core optical fiber collimator 11 and the dispersion component can be manufactured separately, and then the first packaging tube 16 and the second packaging tube 17 are fixed together in a close-contact manner after simple adjustment, so that the whole packaging process is simple and easy to operate.

While the present application has been described with reference to preferred embodiments, it is understood that the terminology used is intended to be in the nature of words of description and illustration, rather than of limitation. As the present application may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.