CN220019930U - Wavelength division multiplexer - Google Patents

Abstract

The utility model provides a wavelength division multiplexer. The wavelength division multiplexer comprises an input collimating lens, a flat light waveguide and an output focusing lens along the light path transmission direction, wherein a super-surface structure is arranged on at least one side surface of the flat light waveguide, the input collimating lens is used for transmitting composite light into the flat light waveguide, the composite light is divided into light with multiple wavelengths through diffraction transmission of the flat light waveguide, the light with multiple wavelengths is emitted from the flat light waveguide at different angles, and the output focusing lens is used for receiving the light with multiple wavelengths emitted from the flat light waveguide. The utility model solves the problem of large insertion loss of the wavelength division multiplexer in the prior art.

Description

Wavelength division multiplexer

Technical Field

The utility model relates to the technical field of optical communication equipment, in particular to a wavelength division multiplexer.

Background

Wavelength division multiplexer (Wavelength Division Multiplexer, abbreviated as WDM) is a common key device in an optical communication system, and can transmit optical signals with different wavelengths to an optical fiber, so as to improve the communication data volume carried by a single optical fiber, save optical fiber resources, and often be used at a data transmitting end and a data receiving end.

The existing wavelength division multiplexer generally comprises three types, wherein the first type is a wavelength division multiplexer based on a thin film filter, the second type is a wavelength division multiplexer, and the third type is a wavelength division multiplexer based on a traditional diffraction grating. All three wavelength division multiplexer schemes currently have some defects:

the wavelength division multiplexer based on the thin film filters consists of a plurality of thin film filters, is limited by high requirements of the narrow-band filters on the incident angle of light and high insertion loss, and the larger the number of the filters is, the larger the overall size and the insertion loss are, so that the wavelength division multiplexer is difficult to integrate more channels.

The wavelength division multiplexer based on the flat-plate optical waveguide utilizes the grating, and the defects of large insertion loss and temperature sensitivity are commonly existed due to the diffraction characteristic of the grating. Polarization dependent effects can occur in slab waveguides and reflective gratings due to the ubiquitous birefringence effect in slab waveguides. When the polarization state of the incident light changes randomly, the output power of the reflective grating can change in a fluctuating way, and the signal to noise ratio is reduced, so that the error rate is increased, and the reflective grating has a larger influence in an optical fiber communication system.

The wavelength division multiplexer based on the traditional diffraction grating has the problems of large size of a coupling structure and large coupling insertion loss when being coupled into an optical fiber because diffraction of the grating is carried out in free space. Meanwhile, the traditional reticle grating is generally formed by a large number of parallel equal-width equidistant slits (reticles) carved on a plane glass or metal sheet, is sensitive to polarization, and requires an additional polarization conversion element to modulate an optical field (such as CN 111965762A), so that the whole optical path is more complex and the cost is increased.

That is, the wavelength division multiplexer in the prior art has a problem of large insertion loss.

Disclosure of Invention

The utility model mainly aims to provide a wavelength division multiplexer so as to solve the problem of large insertion loss of the wavelength division multiplexer in the prior art.

In order to achieve the above object, the present utility model provides a wavelength division multiplexer, including an input collimating lens, a planar optical waveguide, and an output focusing lens along a transmission direction of an optical path, at least one side surface of the planar optical waveguide is provided with a super surface structure, wherein the input collimating lens is used for transmitting composite light into the planar optical waveguide, the composite light is divided into light with multiple wavelengths through diffraction transmission of the planar optical waveguide, the light with multiple wavelengths is emitted from the planar optical waveguide at different angles, and the output focusing lens is used for receiving the light with multiple wavelengths emitted from the planar optical waveguide.

Further, the planar optical waveguide is a reflective planar optical waveguide, and in this case, the input collimating lens and the output focusing lens are located on the same side of the reflective planar optical waveguide.

Further, the planar optical waveguide is a transmissive planar optical waveguide, and at this time, the input collimating lens and the output focusing lens are respectively located on different sides of the transmissive planar optical waveguide.

Further, the number of the input collimating lenses is one, the number of the output focusing lenses is multiple, the plurality of the output focusing lenses are arranged in an array and are independently arranged, and the plurality of the output focusing lenses are in one-to-one correspondence with light with multiple wavelengths.

Further, the input collimating lens is one, the output focusing lenses are a plurality of, the wavelength division multiplexer further comprises a substrate, and the plurality of output focusing lenses are arranged on the substrate in an array.

Further, the input collimating lenses are multiple, the output focusing lenses are multiple, each group of output focusing lenses comprises multiple output focusing lenses which are arranged in an array, and each input collimating lens corresponds to one group of output focusing lenses.

Further, a plurality of input collimating lenses are arranged in an array.

Further, a plurality of input collimating lenses are provided independently, or a plurality of input collimating lenses are integrated on one substrate.

Further, a plurality of output focus lenses of the group of output focus lenses are independently provided, or a plurality of output focus lenses of the group of output focus lenses are integrated on one substrate.

Further, the plurality of output focusing lenses are arranged, and at least two wavelengths of light in the plurality of wavelengths share one output focusing lens.

Further, the surface of the input collimating lens is one of a spherical surface, an aspherical surface and a super surface; and/or the surface of the output focusing lens is one of a spherical surface, an aspherical surface and a super surface.

Further, the super surface comprises a plurality of nano structures, the shapes of the nano structures of different types are different, and the shapes of the nano structures correspond to the shape of the light spots.

By applying the technical scheme of the utility model, the wavelength division multiplexer comprises an input collimating lens, a flat light waveguide and an output focusing lens along the light path transmission direction, wherein the super-surface structure is arranged on at least one side surface of the flat light waveguide, the input collimating lens is used for transmitting composite light into the flat light waveguide, the composite light is divided into light with multiple wavelengths through the diffraction transmission of the flat light waveguide, the light with multiple wavelengths is emitted from the flat light waveguide at different angles, and the output focusing lens is used for receiving the light with multiple wavelengths emitted from the flat light waveguide.

The super surface structure is arranged on at least one side surface of the flat light waveguide, and the super surface structure is arranged, so that the flat light waveguide is insensitive to polarization of light while the light transmission efficiency is basically not lost in the process of carrying out diffraction and light splitting on composite light, and the dispersion consistent with the traditional diffraction grating can be achieved, and beam splitting and beam combining of different wavelengths are realized. The planar optical waveguide with the super-surface structure can achieve beam splitting or beam combination without polarization conversion of an optical field, wavelength multiplexing is achieved, and the effect of small insertion loss is achieved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the utility model. In the drawings:

FIG. 1 shows a schematic optical path diagram of a wavelength division multiplexer according to an alternative embodiment of the present utility model;

FIG. 2 shows a schematic optical path diagram of a wavelength division multiplexer according to another alternative embodiment of the present utility model;

FIG. 3 shows a schematic optical path diagram of an input collimating lens of a wavelength division multiplexer of the present utility model;

FIG. 4 shows a schematic optical path diagram of an output focusing lens of the wavelength division multiplexer of the present utility model;

FIG. 5 shows a schematic diagram of spots of different wavelengths;

FIG. 6 shows a schematic optical path diagram of a wavelength division multiplexer according to another alternative embodiment of the present utility model;

fig. 7 shows a schematic diagram of a slab optical waveguide of a wavelength division multiplexer according to an alternative embodiment of the present utility model.

Wherein the above figures include the following reference numerals:

10. an input collimating lens; 20. a planar optical waveguide; 21. a nano-pillar; 22. a base layer; 30. and outputting a focusing lens.

Detailed Description

It should be noted that, without conflict, the embodiments of the present utility model and features of the embodiments may be combined with each other. The utility model will be described in detail below with reference to the drawings in connection with embodiments.

It is noted that all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs unless otherwise indicated.

In the present utility model, unless otherwise indicated, terms of orientation such as "upper, lower, top, bottom" are used generally with respect to the orientation shown in the drawings or with respect to the component itself in the vertical, upright or gravitational direction; also, for ease of understanding and description, "inner and outer" refers to inner and outer relative to the profile of each component itself, but the above-mentioned orientation terms are not intended to limit the present utility model.

In order to solve the problem of large insertion loss of the wavelength division multiplexer in the prior art, the utility model provides the wavelength division multiplexer.

As shown in fig. 1 to 7, the wavelength division multiplexer includes an input collimating lens 10, a planar optical waveguide 20, and an output focusing lens 30 along an optical path transmission direction, at least one side surface of the planar optical waveguide 20 is provided with a super surface structure, wherein the input collimating lens 10 is used for collimating and transmitting the composite light into the planar optical waveguide 20, the composite light is divided into light with multiple wavelengths through diffraction transmission of the planar optical waveguide 20, the light with multiple wavelengths is emitted from the planar optical waveguide 20 at different angles, and the output focusing lens 30 is used for receiving the light with multiple wavelengths emitted from the planar optical waveguide 20.

At least one side surface of the flat light waveguide 20 is provided with a super surface structure, and by arranging the super surface structure, the flat light waveguide 20 is insensitive to polarization of light while basically not losing light transmission efficiency in the process of carrying out diffraction and light splitting on composite light, and can achieve the dispersion consistent with the traditional diffraction grating, thereby realizing beam splitting and beam combining of different wavelengths. The use of the planar optical waveguide 20 having the super-surface structure can achieve the effects of splitting or combining the light beam, multiplexing the wavelength, and reducing the insertion loss without performing polarization conversion on the light field.

It should be noted that, the super surface structure may be disposed only on one side surface of the planar optical waveguide 20, and the super surface structure is located on the light incident side of the planar optical waveguide 20; the super-surface structure can also be arranged on the two side surfaces of the super-surface structure. The super surface structure is composed of a plurality of arrays of nano-pillars 21, and the shape and size of the nano-pillars 21 can be adjusted according to design to ensure high diffraction and transmission efficiency. The flat optical waveguide 20 can disperse the monochromatic light constituting the broad spectrum composite light, and the angle of dispersion is related to the wavelength of each monochromatic light. The kinds of the nano-pillars 21 in the planar light guide 20 include one or more kinds, and when the kinds of the nano-pillars 21 in the planar light guide 20 include a plurality of kinds, the sizes or shapes of the nano-pillars 21 of different kinds are different, and the shapes and sizes of the nano-pillars 21 correspond to the shapes and sizes of the spots of the monochromatic light. For example, in an alternative embodiment shown in fig. 7, the slab optical waveguide 20 includes a substrate layer 22 and a plurality of nano-pillars 21 arranged in an array on one side surface of the substrate layer 22, when the spot shape of the monochromatic light is circular, the projection shape of the corresponding nano-pillars 21 on the substrate layer 22 is also circular, when the spot shape of the monochromatic light is quadrilateral, the projection shape of the corresponding nano-pillars 21 on the substrate layer 22 is also quadrilateral, and so on.

In an alternative embodiment of the utility model, as shown in fig. 1, the planar light guide 20 is a reflective planar light guide that diffracts the incident composite light and then outputs light of multiple wavelengths at different angles in a reflective form. At this time, the input collimator lens 10 and the output focusing lens 30 are located on the same side of the reflective flat-panel optical waveguide.

In another alternative embodiment of the present utility model, as shown in fig. 2, the planar light guide 20 is a transmissive planar light guide for diffracting and splitting the incident composite light and then outputting light of various wavelengths at different angles in a transmissive form. At this time, the input collimator lens 10 and the output focusing lens 30 are respectively located at different sides of the transmissive planar lightwave circuit.

The planar optical waveguide 20 may be either reflective or transmissive. The two forms only bring about different device layouts, and have no essential difference in the realization of device functions, so that the flat optical waveguide 20 in different forms can be selected according to actual requirements. The material of the planar optical waveguide 20 may be glass or silicon.

Referring to fig. 1 and 2, the wavelength λ of the composite light includes light of a plurality of wavelengths from wavelengths λ1 to λn. The input collimating lens 10 is one, the composite light output by the input end is incident to the input collimating lens 10, the input collimating lens 10 is used for collimating and deflecting the composite light and then enters the flat-plate optical waveguide 20 under the diffraction condition, and the light with different wavelengths is diffracted and split through the flat-plate optical waveguide 20, so that the light with different emergent angles are provided. The output focusing lenses 30 are multiple, the output focusing lenses 30 are arranged in an array, the output focusing lenses 30 are in one-to-one correspondence with light of multiple wavelengths, the corresponding output focusing lenses 30 are arranged according to the emergent angles and the intervals of the light of different wavelengths, so that one output focusing lens 30 corresponds to light of a single wavelength, the modulation of a light field is realized through the output focusing lenses 30 of the array, the deflection and focusing of the light field are realized, the deflection angles of the light of each output focusing lens 30 can be freely designed, and the intervals of the light of different wavelengths can be controlled.

That is, the light with different wavelengths can be received by the corresponding output focusing lens 30 after being emitted from the flat optical waveguide 20 at different angles, so that the plurality of output focusing lenses 30 are in one-to-one correspondence with the light with different wavelengths, and the output focusing lens 30 deflects and focuses the light with one wavelength corresponding to the light.

Specifically, the material and design mode of the input collimating lens 10 can be reasonably selected according to the total spectral width of wavelength division multiplexing and the light spot size required by shaping the light to the planar optical waveguide 20 by the input collimating lens 10 through which the composite light passes. The material of the input collimating lens 10 may be glass or silicon, the surface of the input collimating lens 10 may be a conventional sphere or an aspheric surface, and the surface of the input collimating lens 10 may be a super surface according to the diffraction principle. Here, the super surface is the above-mentioned super surface structure, and the super surface includes a plurality of nanostructures that are the array setting, and a plurality of nanostructures are divided into multiple, and the shape of different kinds of nanostructures is different, and the shape of nanostructure corresponds with the facula shape of light beam, through setting up the super surface, is favorable to increasing the transmission efficiency of input collimating lens 10.

As shown in fig. 3, the shape of the input collimating lens 10 may be one of an ellipse, a circle, and a square, or may be cut into a desired shape according to the need, and the ellipse is only shown in the figure.

As shown in fig. 4, the material of the output focusing lens 30 may be glass or silicon. The output focusing lens 30 is used for converging and deflecting light to be output to the optical fiber at the receiving end. The surface of the output focusing lens 30 is one of a spherical surface, an aspherical surface and a super surface. The super surface comprises a plurality of nano structures which are arranged in an array, the plurality of nano structures are divided into a plurality of types, the shapes of the nano structures of different types are different, and the shapes of the nano structures correspond to the shape of light spots of the light beam. When the surface of the output focusing lens 30 is a super surface, the nano structures of the super surfaces of different output focusing lenses 30 have different shapes, and the coupling distance, the coupling precision and the coupling angle can be designed independently for each single wavelength light, so that the receiving-end optical fibers with different distances, different angles and different pitches can be matched.

In the above embodiment, the output focusing lenses 30 for one input collimating lens 10 are plural, and the plural output focusing lenses 30 are arranged in an array and each output focusing lens 30 is independently provided.

However, in another alternative embodiment of the present utility model, the plurality of output focusing lenses 30 for one input collimating lens 10 are arranged on the substrate in an array, that is, the plurality of output focusing lenses 30 are integrated on one substrate and share one substrate, and the plurality of output focusing lenses 30 are arranged in one-to-one correspondence with the light of multiple wavelengths, so that the substrate provides the arrangement positions for the output focusing lenses 30, ensuring the reliability of use of each output focusing lens 30, and ensuring that each output focusing lens 30 can stably receive the light of the corresponding wavelength.

As shown in FIG. 5, the super-surface structure is benefited or the super-surface can be processed and manufactured by a semiconductor process, the shape of the modulation area of the optical field can be arbitrarily adjusted, and the method is not limited to the traditional round light spot, for example, an elliptical light spot or a square light spot can be used for collecting and modulating as many light spot areas with single wavelength as possible, so that the missing optical field intensity is reduced, the insertion loss of a device is reduced, and the coupling efficiency is improved. That is, since the optical path is reversible, the light propagation direction in fig. 1 or fig. 2 is reversed, so that the light of a plurality of wavelengths can be combined.

In another alternative embodiment shown in fig. 6, the input collimating lenses 10 are plural, the plate optical waveguide 20 is transmissive, the output focusing lenses 30 are plural, each group of output focusing lenses 30 includes plural output focusing lenses 30 arranged in an array, and the plural input collimating lenses 10 are arranged in an array, and each input collimating lens 10 corresponds to one group of output focusing lenses 30. The arrangement is such that the input collimating lens 10 and the output focusing lens 30 are both arrayed, enabling M x N wavelength division multiplexing.

In this case, the plurality of input collimating lenses 10 may be independently and separately provided, or the plurality of input collimating lenses 10 may be integrated on one substrate. The plurality of output focusing lenses 30 of the group of output focusing lenses are independently and separately provided, or the plurality of output focusing lenses 30 of the group of output focusing lenses are integrated on one substrate. The arrangement of the input collimator lens 10 and the output focusing lens 30 can be selected according to the actual situation.

As shown in fig. 6, the number of the input collimator lenses 10 is two, and the upper input collimator lens 10 is used for receiving a composite light having a wavelength λ, which includes light of a single wavelength from a wavelength λ1 to a wavelength λn; the following input collimator lens 10 is used to receive another composite light of wavelength λm, which includes light of a single wavelength from wavelength λ1n to wavelength λmn.

In another alternative embodiment of the present utility model, at least two wavelengths of light may share one output focusing lens 30, whether for one input collimating lens 10 or a plurality of input collimating lenses 10. For example, light of wavelength λ1 and light of wavelength λ2 may share one output focusing lens 30, thereby enabling adjustment of different bandwidths.

In another alternative embodiment of the present utility model, individual wavelength division multiplexers may be cascaded together, and the cascade combination may be performed according to different requirements. For example, for the wavelength λmn of the incident light, the wavelengths λm1, λmn2 … … λ mnk can be further decomposed by cascading.

It will be apparent that the embodiments described above are merely some, but not all, embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present utility model without making any inventive effort, shall fall within the scope of the present utility model.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present utility model. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present utility model and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the utility model described herein may be implemented in sequences other than those illustrated or otherwise described herein.

The above description is only of the preferred embodiments of the present utility model and is not intended to limit the present utility model, but various modifications and variations can be made to the present utility model by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims (12)

1. A wavelength division multiplexer is characterized by comprising an input collimating lens (10), a flat optical waveguide (20) and an output focusing lens (30) along the transmission direction of an optical path, wherein at least one side surface of the flat optical waveguide (20) is provided with a super-surface structure,

the input collimating lens (10) is used for transmitting composite light into the flat light guide (20), the composite light is divided into light with multiple wavelengths through diffraction transmission of the flat light guide (20), the light with multiple wavelengths is emitted by the flat light guide (20) at different angles, and the output focusing lens (30) is used for receiving the light with multiple wavelengths emitted by the flat light guide (20).

2. The wavelength division multiplexer of claim 1 wherein the planar optical waveguide (20) is a reflective planar optical waveguide, and wherein the input collimating lens (10) and the output focusing lens (30) are located on the same side of the reflective planar optical waveguide.

3. Wavelength division multiplexer according to claim 1, characterized in that the planar optical waveguide (20) is a transmissive planar optical waveguide, in which case the input collimating lens (10) and the output focusing lens (30) are located on different sides of the transmissive planar optical waveguide, respectively.

4. The wavelength division multiplexer according to claim 1, wherein the number of the input collimating lenses (10) is one, the number of the output focusing lenses (30) is plural, the plural output focusing lenses (30) are arranged in an array and are independently arranged, and the plural output focusing lenses (30) are in one-to-one correspondence with the light of plural wavelengths.

5. The wavelength division multiplexer of claim 1, wherein the input collimating lens (10) is one, the output focusing lens (30) is a plurality, the wavelength division multiplexer further comprises a substrate, and the plurality of output focusing lenses (30) are arranged on the substrate in an array.

6. The wavelength division multiplexer of claim 1, wherein the input collimating lenses (10) are a plurality of, the output focusing lenses (30) are a plurality of groups, each group of the output focusing lenses (30) comprises a plurality of the output focusing lenses (30) arranged in an array, and each input collimating lens (10) corresponds to a group of the output focusing lenses (30).

7. A wavelength division multiplexer according to claim 6, wherein a plurality of said input collimating lenses (10) are arranged in an array.

8. The wavelength division multiplexer according to claim 6, wherein a plurality of the input collimating lenses (10) are provided independently or wherein a plurality of the input collimating lenses (10) are integrated on one substrate.

9. The wavelength division multiplexer of claim 6, wherein a plurality of the output focusing lenses of a set of the output focusing lenses (30) are provided independently or wherein a plurality of the output focusing lenses of a set of the output focusing lenses (30) are integrated on one substrate.

10. The wavelength division multiplexer of claim 1, wherein the output focusing lens (30) is a plurality, and at least two wavelengths of light of the plurality of wavelengths share one output focusing lens (30).

11. Wavelength division multiplexer according to any one of claims 1 to 10, wherein,

the surface of the input collimating lens (10) is one of a spherical surface, an aspherical surface and a super surface; and/or

The surface of the output focusing lens (30) is one of a spherical surface, an aspherical surface and a super surface.

12. The wavelength division multiplexer of claim 11 wherein the supersurface comprises a plurality of nanostructures, the nanostructures of different species having different shapes, the shapes of the nanostructures corresponding to the shape of the light spot.