CN217879719U - High-order Gaussian optical filter - Google Patents

Abstract

The utility model discloses a high-order Gaussian optical filter, including fiber input end, collimater, grating, rotatable speculum and fiber output end, the light beam is imported from the fiber input end and is passed through the optic fibre in proper order, the collimater, the grating with the rotatable speculum, the rotatable speculum reflects the light beam and passes through the grating in proper order, the collimater gets back to the fiber output end; the high-order Gaussian optical filter further comprises a diaphragm, and the diaphragm is arranged on the collimator or the grating or between the grating and the rotatable reflecting mirror. The proper diaphragm is arranged in the light path, and the required spectrum is selected, so that the filtering function of high-order Gaussian light is realized, the ratio of 3dB bandwidth to 20dB bandwidth is adjusted, the filtering function of the high-order Gaussian light can be realized by the filtered light beam, the application field is expanded, and the device is small in size, simple in structure and stable in performance.

Description

High-order Gaussian optical filter

Technical Field

The utility model relates to an optical communication technical field especially relates to a high-order gaussian optical filter.

Background

The tunable optical filter is an important optical device, is widely applied to the fields of optical communication, photoelectric sensing and detection, particularly has a great amount of applications in a high-speed transmission optical communication system, is a basic optical device in optical communication and data networks, and is applied to optical channel monitoring modules (OCM), 100G and 400G + C-shaped pluggable transceiver modules CFP/CFP2 and low-noise EDFA. Technologies commonly used in tunable optical filters on the market are mach-zehnder (M-Z) interference, fabry-perot (F-P) resonators or etalons, multilayer dielectric film filtering, and diffraction grating-micro-electro-mechanical systems (MEMS). The diffraction grating-MEMS technology route is receiving more and more attention due to its advantages of large coverage wavelength range, fast tuning speed, relatively simple structure and algorithm, easy preparation, high reliability, etc.

In the field of optical communications, communication bandwidth is an important index parameter for measuring communication quality. The tunable optical filter has a function of flexibly selecting a required wavelength, brings convenience to an optical communication system, and has been widely applied. The tunable optical filter based on the micro-electro-mechanical system (MEMS) technology utilizes the grating as a light splitting element, selects the required working wavelength by controlling the angle of the MEMS micro-mirror, and has the advantages of small volume, simple structure, stable performance and the like. However, in recent years, the application demand for high-order gaussian light is increasing, and the tunable filter for such light beam is currently researched less, the output bandwidth is weak in adjustment capability, and the filtering demand for high-order gaussian light cannot be met, especially the conventional ratio of 3dB bandwidth to 20dB bandwidth cannot meet the filtering demand for high-order gaussian light, and therefore the blank in the high-order gaussian light is urgently needed to be filled.

Disclosure of Invention

The utility model provides a high order gaussian optical filter aims at solving the unable effectual problem of filtering out the high order gaussian light of traditional wave filter.

In a first aspect, the present invention provides a high-order gaussian optical filter, including an optical fiber input end, a collimator, a grating, a rotatable mirror and an optical fiber output end, wherein a light beam is input from the optical fiber input end and sequentially passes through the optical fiber, the collimator, the grating and the rotatable mirror, and the rotatable mirror selects a light beam with a suitable wavelength to reflect and sequentially passes through the grating and the collimator to return to the optical fiber output end; the high-order Gaussian optical filter further comprises at least one diaphragm, and the diaphragm is arranged on the collimator or the grating or between the grating and the rotatable reflecting mirror.

Furthermore, the diaphragm is provided with two first diaphragms and two second diaphragms, the first diaphragms are arranged on the collimators, and the second diaphragms are arranged on the gratings.

Further, the diaphragm is equipped with two and is first diaphragm and second diaphragm respectively, first diaphragm is located on the grating, the second diaphragm is located the grating with between the rotatable speculum.

Furthermore, the diaphragm is provided with two first diaphragms and two second diaphragms, the first diaphragms are arranged on the collimators, and the second diaphragms are arranged between the gratings and the rotatable reflecting mirrors.

Further, the diaphragm is equipped with three and is first diaphragm and second diaphragm and third diaphragm respectively, first diaphragm is located on the collimater, the second diaphragm is located on the grating, the third diaphragm is located the grating with between the rotatable speculum.

Further, the diaphragm is arranged on one side, close to the grating, of the collimator.

Further, the diaphragm is arranged on one side, close to the collimator, of the grating.

Further, the diaphragm is arranged on the end face of the optical fiber.

Further, the fiber mode field diameters of the fiber input end and the fiber output end range from 9 μm to 20 μm.

Further, the grating incident angle ranges from 44 ° to 50 °.

Further, the grating line pairs of the grating are 800 to 1100.

Further, the diaphragm is a through hole; or the diaphragm is a light-passing element with a gradient PR film.

Compared with the prior art, the beneficial effects of the utility model are that: by arranging the optical fiber input end, the collimator, the grating, the rotatable reflector and the optical fiber output end, light beams are input from the optical fiber input end, reflected by the rotatable reflector through the collimator and the grating, part of the light beams return to the grating along the original path, the collimator returns to the optical fiber output end to be output, and part of the light beams return to the light path to deviate to a certain extent, wherein a diaphragm is arranged in the light path, the diaphragm can be arranged on the collimator, or arranged on the grating, or arranged between the grating and the rotatable reflector, and the deviated light beams are blocked by arranging the diaphragm, so that the effect of tightening up the bandwidth is achieved, the filtering function of high-order Gaussian light is realized, the size is small, the structure is simple, and the performance is stable.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without any creative effort.

Fig. 1 shows a schematic diagram of a high-order gaussian optical filter according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a high order Gaussian optical filter according to another embodiment of the present invention;

fig. 3 shows a schematic diagram of a high-order gaussian optical filter according to another embodiment of the present invention;

fig. 4 shows a schematic diagram of a grating filtering optical path of a high-order gaussian optical filter according to an embodiment of the present invention;

fig. 5 shows a spectral diagram of an un-stop output signal of a high-order gaussian optical filter according to an embodiment of the present invention;

fig. 6 shows a schematic diagram of a spectral pattern of an output signal after adding a diaphragm in the high-order gaussian optical filter according to the embodiment of the present invention;

11. an optical fiber input end; 12. an optical fiber output end; 20. a collimator; 30. a diaphragm; 40. a grating; 50. the mirror can be rotated.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be further understood that the term "and/or" as used in the specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.

The embodiment of the application provides a high-order Gaussian optical filter, solves the problem that the bandwidth of the existing high-order Gaussian optical filter is not adjustable, and achieves the effect of tightening up the bandwidth by adding a diaphragm in a light path to block partial deviated light beams, thereby realizing the filtering function of high-order Gaussian light.

In order to solve the problem of bandwidth adjustment, the technical solution in the embodiment of the present application adopts the following general idea:

the optical filter splits light through the grating, different wavelengths are changed into parallel light with different angles after passing through the grating, the rotatable reflector (MEMS reflector) is only perpendicular to the central wavelength and can return along the original optical path, the return optical paths of other wavelengths deviate to a certain extent, the wavelength deviation farther from the central wavelength is larger, the diaphragm can block off the deviated light, the 3dB bandwidth and the 20dB bandwidth output by the optical filter are narrowed, and the filtered light beam can realize the filtering function of high-order Gaussian light. That is to say, the 3dB bandwidth and the 20dB bandwidth of device output are adjusted through the diaphragm, the problem that the bandwidth adjusting capacity is weak is solved, the filtering requirement of high-order Gaussian light is met, and the device is small in size, simple in structure and stable in performance.

In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and the specific embodiments.

The first embodiment is as follows:

referring to fig. 1-4, an embodiment of the present invention provides a high-order gaussian optical filter, including an optical fiber input end 11, a collimator 20, a grating 40, a rotatable mirror 50 and an optical fiber output end 12, wherein a light beam is input from the optical fiber input end 11 and sequentially passes through the optical fiber, the collimator 20, the grating 40 and the rotatable mirror 50, and the rotatable mirror 50 selects a light beam with a suitable wavelength to reflect sequentially passing through the grating 40 and the collimator 20 and returning to the optical fiber output end 12; the high-order gaussian optical filter further includes at least one diaphragm 30, and the diaphragm 30 is disposed on the collimator 20, or on the grating 40, or between the grating 40 and the rotatable mirror 50.

Specifically, the number of the diaphragms 30 in this embodiment is one, and the diaphragms 30 may be disposed on the collimator 20, on the grating 40, or between the grating 40 and the rotatable mirror 50. That is, the diaphragm 30 of the present embodiment can be set at one of the three positions, and can all function to adjust the bandwidth.

By implementing the embodiment, the diaphragm 30 is additionally arranged in the optical path, the diaphragm 30 is arranged on the collimator 20 or on the grating 40 or between the grating 40 and the rotatable reflecting mirror 50, and the deviation light beam reflected from the rotatable reflecting mirror 50 is blocked by the diaphragm 30, so that the function of tightening the bandwidth is achieved, and the filtering function of high-order Gaussian light is realized.

In the present embodiment, the collimator 20 is a collimating mirror, and the collimating mirror is used to improve the collimation of the light beam. The grating 40 is a diffraction grating 40, and the diffraction grating 40 is for dispersing the light beam exiting from the collimator mirror into diffracted lights having different diffraction angles. The rotatable mirror 50 is a MEMS mirror that deflects to reflect diffracted light at a particular angle to achieve a selection of wavelengths.

Referring to fig. 1, in the present embodiment, the diaphragm 30 is disposed on a side of the collimator 20 close to the grating 40. Specifically, the collimator 20 has a light-in side and a light-out side (with respect to the incidence of the light beam), wherein the side close to the fiber input end 11 is the light-in side, and the side close to the grating 40 is the light-out side, and the diaphragm 30 of the present embodiment is disposed on the light-out side. The MEMS mirror deflects the reflected beam, and when a part of the deflected beam returns from the grating 40 to the diaphragm 30 on the light exit side of the collimator 20, the deflected beam is blocked by the diaphragm 30, so as to achieve the effect of tightening the bandwidth and realize the filtering function of high-order gaussian light.

Referring to fig. 2, in the present embodiment, the diaphragm 30 is disposed on a side of the grating 40 close to the collimator 20. Specifically, the grating 40 has a light-in side and a light-out side (with respect to the incidence of the light beam), wherein the side close to the collimator 20 is the light-in side, and the side close to the rotatable mirror 50 is the light-out side, and the diaphragm 30 of the present embodiment is disposed on the light-in side. The MEMS mirror deflects the reflected beam and a portion of the deflected beam is blocked by the stop 30 when it returns from the rotatable mirror 50 to the stop 30 on the light incident side of the grating 40, thereby achieving the effect of tightening the bandwidth and achieving the filtering function of high-order gaussian light.

Referring to fig. 3, in the present embodiment, the diaphragm 30 is disposed between the grating 40 and the rotatable mirror 50. Specifically, the stop 30 is disposed intermediate the optical path traveled by the grating 40 and the rotatable mirror 50. The MEMS mirror deflects the reflected beam, and part of the deflected beam is blocked by the diaphragm 30, so that the effect of tightening the bandwidth is achieved, and the filtering function of high-order Gaussian light is realized.

In this embodiment, the stop 30 is provided on the end face of the optical fiber. Specifically, the end face of the optical fiber input end 11, may also be the end face of the optical fiber output end 12.

In this embodiment, the fiber mode field diameters of the fiber input end 11 and the fiber output end 12 range from 9 μm to 20 μm. The present embodiment achieves the adjustment effect on the bandwidth by limiting the mode field diameter of the optical fiber to shape the transmitted light beam.

Illustratively, the mode field diameter of the optical fiber in this embodiment is 9 μm. Illustratively, the mode field diameter of the optical fiber in this embodiment is 10 μm. Illustratively, the mode field diameter of the fiber in this embodiment is 11 μm. Illustratively, the mode field diameter of the optical fiber in this embodiment is 12 μm. Illustratively, the mode field diameter of the optical fiber in this embodiment is 13 μm. Illustratively, the mode field diameter of the optical fiber in this embodiment is 14 μm. Illustratively, the mode field diameter of the fiber in this embodiment is 15 μm. Illustratively, the mode field diameter of the fiber in this embodiment is 16 μm. Illustratively, the mode field diameter of the fiber in this embodiment is 17 μm. Illustratively, the mode field diameter of the optical fiber in this embodiment is 18 μm. Illustratively, the mode field diameter of the fiber in this embodiment is 19 μm. Illustratively, the mode field diameter of the fiber in this embodiment is 20 μm.

In the present embodiment, the incident angle of the grating 40 ranges from 44 ° to 50 °. The range of the incident angle of the grating 40 is limited to ensure the effect of narrowing the bandwidth of the output signal. Illustratively, the grating 40 in this embodiment has an incident angle of 44 °. Illustratively, the grating 40 in this embodiment has an incident angle of 45 °. Illustratively, the grating 40 in this embodiment has an incident angle of 46 °. Illustratively, the grating 40 in this embodiment has an incident angle of 47 °. Illustratively, the grating 40 in this embodiment has an incident angle of 48 °. Illustratively, the grating 40 in this embodiment has an incident angle of 49 °. Illustratively, the grating 40 in this embodiment has an incident angle of 50 °.

In the present embodiment, the line pair number of the grating 40 is 800 to 1100. The effect of narrowing the bandwidth of the output signal is ensured by limiting the line number of the grating 40. Specifically, the number of line pairs of the grating 40 in the present embodiment is about 1000 or about 900.

In this embodiment, the diaphragm 30 is a through hole; alternatively, the diaphragm 30 is a light-transmitting element with a graded PR film. The through hole is used for passing the light beam, and the diaphragm part outside the through hole is used for blocking the deviated light beam. The part of the graded PR film that passes through the element is used to pass the beam and the rest is used to block the deviated beam.

In summary, in order to realize the adjustment of the bandwidth, the present embodiment shapes the transmitted light beam by the preferred mode field diameter of the optical fiber, thereby realizing the adjustment of the bandwidth. And secondly, the diaphragm 30 is added on optical elements such as a collimating mirror and a grating 40 of the TF module, and the adjustment effect on the bandwidth is realized by optimizing the size of the diaphragm 30 and the position of the diaphragm in the optical path. Therefore, the 3dB bandwidth and the 20dB bandwidth output by the tunable optical filter are narrowed by adjusting the 3dB bandwidth and the 20dB bandwidth output by the diaphragm 30, and the filtered light beam can realize the filtering function of high-order Gaussian light, so that the application field is expanded.

The spectral curves of the optical filter without the stop 30 and the optical filter with the stop 30 of the present embodiment are compared below.

Fig. 5 and 6 show spectral curves of output signals of two filters without a diaphragm 30, fig. 5 shows a spectral curve without a diaphragm 30, the ratio of 20dB bandwidth to 3dB bandwidth is about 2.8, the spectral curve is a traditional gaussian curve, the value is reduced to 2.2 after the diaphragm 30 is added in the optical path, fig. 6 shows that the whole gaussian curve is tightened, and the output signal is modulated into high-order gaussian light, so that the requirements of the current communication field can be met.

The technical scheme adopted by the embodiment is that on the structure of the traditional tunable optical filter based on the MEMS technology, the components of the traditional tunable optical filter are an optical fiber, a collimating mirror, a grating 40 and an MEMS reflecting mirror in sequence along an optical path, and a 3-diaphragm 30 is added in the optical path. Referring to fig. 4, the tunable optical filter splits light through the grating 40, different wavelengths are changed into parallel light with different angles after passing through the grating 40, the MEMS mirror is only perpendicular to the central wavelength and can return along the original optical path, return optical paths with other wavelengths deviate to a certain extent, the wavelength deviation farther from the central wavelength is larger, and the diaphragm 30 blocks the deviated light, so that the effect of tightening the bandwidth is achieved, and the filtering function of high-order gaussian light is realized. Relevant parameters in the scheme are determined through simulation analysis and experimental tests, the diameter range of a used optical fiber mode field is determined to be 9-12 micrometers, the incident angle of the grating 40 is limited to be 44-50 degrees, the line logarithm of the used grating 40 is about 1000 degrees, the effect of narrowing the bandwidth of an output signal is achieved through relevant system parameter matching and adjustment of the position and the size of the diaphragm 30, a common light beam is converted into a high-order Gaussian light beam, and the specific application requirements are met. The 3dB bandwidth and the 20dB bandwidth of the output signal of the tunable optical filter are improved, the proportion of the two bandwidths is reduced, and the filtering of high-order Gaussian light can be realized.

Example two

The embodiment of the utility model provides a still provide a high order gaussian optical filter, the high order gaussian optical filter of this embodiment is similar with the high order gaussian optical filter in the above-mentioned embodiment one, and the difference lies in the quantity difference of diaphragm 30, and the position difference that diaphragm 30 set up. In this embodiment, the diaphragm 30 is provided with two first diaphragms 30 and two second diaphragms 30, the first diaphragm 30 is disposed on the grating 40, and the second diaphragm 30 is disposed between the grating 40 and the rotatable mirror 50. Specifically, the number of the diaphragms 30 in this embodiment is two, one of the two diaphragms 30 is disposed on the collimator 20, the other one is disposed on the grating 40, and the two diaphragms 30 respectively shield the deviated light beams, so as to achieve the effect of tightening the bandwidth and realize the filtering function of the high-order gaussian light.

EXAMPLE III

The embodiment of the utility model provides a still provide a high order gaussian optical filter, the high order gaussian optical filter of this embodiment is similar with the high order gaussian optical filter in the above-mentioned embodiment one, and the difference lies in the quantity difference of diaphragm 30, and the position difference that diaphragm 30 set up. The diaphragm 30 is provided with two first diaphragms 30 and two second diaphragms 30, the first diaphragms 30 are arranged on the grating 40, and the second diaphragms 30 are arranged between the grating 40 and the rotatable reflecting mirror 50. Specifically, the number of the diaphragms 30 of the embodiment is two, one of the two diaphragms 30 is disposed on the grating 40, and the other diaphragm is disposed between the grating 40 and the rotatable mirror 50, and the two diaphragms 30 respectively shield the deviated light beams, so as to achieve the effect of tightening up the bandwidth and realize the filtering function of the high-order gaussian light.

Example four

The embodiment of the utility model provides a still provide a high order gaussian optical filter, the high order gaussian optical filter of this embodiment is similar with the high order gaussian optical filter in the above-mentioned embodiment one, and the difference lies in diaphragm 30's quantity different, and the position that diaphragm 30 set up is different. The diaphragm 30 is provided with two first diaphragms 30 and two second diaphragms 30, the first diaphragm 30 is arranged on the collimator 20, and the second diaphragm 30 is arranged between the grating 40 and the rotatable reflector 50. Specifically, the number of the diaphragms 30 of the present embodiment is two, one of the two diaphragms 30 is disposed on the collimator 20, and the other one is disposed between the grating 40 and the rotatable mirror 50, and the two diaphragms 30 respectively shield the deviated light beams, so as to achieve the effect of tightening up the bandwidth and realize the filtering function of the high-order gaussian light.

EXAMPLE five

The embodiment of the utility model provides a still provide a high order gaussian optical filter, the high order gaussian optical filter of this embodiment is similar with the high order gaussian optical filter in the above-mentioned embodiment one, and the difference lies in diaphragm 30's quantity different, and the position that diaphragm 30 set up is different. The diaphragm 30 is provided with three first diaphragms 30, second diaphragms 30 and third diaphragms 30, the first diaphragms 30 are arranged on the collimator 20, the second diaphragms 30 are arranged on the gratings 40, and the third diaphragms 30 are arranged between the gratings 40 and the rotatable reflecting mirror 50. Specifically, the number of the diaphragms 30 in this embodiment is three, one of the three diaphragms 30 is disposed on the collimator 20, the other is disposed on the grating 40, and the other is disposed between the grating 40 and the rotatable mirror 50, and the two diaphragms 30 respectively shield the deviated light beams, so as to achieve the effect of tightening up the bandwidth and realize the filtering function of the high-order gaussian light.

The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.

Claims (12)

1. A high-order Gaussian optical filter is characterized by comprising an optical fiber input end, a collimator, a grating, a rotatable reflector and an optical fiber output end, wherein light beams are input from the optical fiber input end and sequentially pass through the optical fiber, the collimator, the grating and the rotatable reflector;

the high-order Gaussian optical filter further comprises at least one diaphragm, and the diaphragm is arranged on the collimator or the grating or between the grating and the rotatable reflecting mirror.

2. The higher order gaussian optical filter of claim 1 wherein said stop is disposed on a side of said collimator adjacent to said grating.

3. The higher order gaussian optical filter of claim 2 wherein said stop is disposed on a side of said grating proximate to said collimator.

4. The higher order gaussian optical filter of claim 2 wherein said stop is disposed at said fiber end face.

5. The higher order Gaussian optical filter of claim 3, wherein the fiber mode field diameters of the fiber input end and the fiber output end range from 9 μm to 20 μm.

6. The higher order Gaussian optical filter of claim 4, wherein the grating incident angle is in a range of 44 ° to 50 °.

7. The higher order Gaussian optical filter of claim 5, wherein the grating has a grating line pair number of 800 to 1100.

8. The higher order Gaussian optical filter of any of claims 1-6 wherein the stop is a through hole; or the diaphragm is a light-transmitting element with a gradient PR film.

9. The higher order Gaussian optical filter according to any one of claims 1 to 6, wherein the diaphragm is provided with two first diaphragms and two second diaphragms, the first diaphragm is provided on the collimator, and the second diaphragm is provided on the grating.

10. The higher order Gaussian optical filter according to any one of claims 1 to 6, wherein the two diaphragms are a first diaphragm and a second diaphragm, the first diaphragm is disposed on the grating, and the second diaphragm is disposed between the grating and the rotatable mirror.

11. The higher order Gaussian optical filter according to any one of claims 1 to 6, wherein the two diaphragms are a first diaphragm and a second diaphragm, the first diaphragm is disposed on the collimator, and the second diaphragm is disposed between the grating and the rotatable mirror.

12. The higher order Gaussian optical filter of any of claims 1 to 6 wherein the aperture is provided with three apertures, a first aperture and a second aperture and a third aperture, the first aperture is provided on the collimator, the second aperture is provided on the grating, and the third aperture is provided between the grating and the rotatable mirror.

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