Volume hologram applied to a cwdm optical splitting assembly

Abstract

The application relates to a volume hologram applied to a CWDM light splitting assembly, which comprises a light source, a first lens, at least one first single-wavelength volume hologram and a second lens or at least one second single-wavelength volume hologram, a plurality of first single-wavelength volume holograms are stacked on the first light-emitting side of the first lens, and a plurality of second single-wavelength volume holograms are arranged in parallel on the second light-emitting side of the second lens. By expanding the laser beam, converting the plane wave, adjusting the distance between the plane waves and adjusting the diffraction angle, the plane waves of different wavelengths can be vertically emitted, so that the collimating lens is not used, and the volume of the application is reduced.

Description

Technical Field

[0001] This application relates to a volumetric holophotograph, and more particularly to a volumetric holophotograph used in a CWDM beam splitter assembly. Background Technology

[0002] With the rapid development of technology, various new technologies rely on information transmission as a bridge for communication or computation. As a result, the demand for information transmission is growing with technological advancements. Data centers or databases that aggregate various information data especially require higher-speed transmission for data exchange and storage. Traditional cables can no longer handle such a large amount of data transmission, so 100Gpds fiber optic transmission architectures (such as Coarse Wavelength Division Multiplexing, CWDM) have been developed. This architecture mainly combines multiple optical signals of different wavelengths transmitted in different optical fibers into a single optical fiber for transmission, and after transmission, it splits the optical signals of different wavelengths to the location where the individual signal is received.

[0003] Please see Figure 1 and Figure 2 Currently, Z-block coatings are mainly used for beam splitting, or arrayed waveguide gratings (AWGs) are used for multi-wavelength combination and splitting. Z-block beam splitting requires an orthographic prism Z1. The incident side of the orthographic prism Z1 has a total internal reflection coating Z2, and the emitting side of the orthographic prism Z1 has at least one broadband filter Z3. When optical fiber Z4 passes through collimating lens Z5, multiple light signals of different wavelengths enter the orthographic prism Z1 from the incident side. Light signals of specific wavelengths will directly penetrate the broadband filter Z3 on the emitting side; while light signals that do not conform to the specific wavelength will be reflected to the total internal reflection coating Z2, and after total internal reflection, to another broadband filter Z3. Therefore, the total internal reflection coating Z2 needs to ensure that multiple non-specific wavelength light signals are all totally reflected. This will lead to... The total internal reflection coating Z2 of the Z Block is relatively complex in design. Through multiple incident, reflection, and total internal reflection processes, light signals of different wavelengths can directly penetrate the multiple broadband filters Z3 on the light-emitting side. Then, each light signal passes through a collimating lens Z5 before entering the next stage. In summary, the total internal reflection coating Z2 of the Z Block has a relatively complex requirement and the overall device is difficult to assemble. Furthermore, since the optical fiber needs to pass through a collimating lens Z5 to guide the incident light into its rhomboid prism Z1, and after passing through each broadband filter Z3, it also needs to pass through the corresponding collimating lens Z5 to make the emitted light perpendicular, the use of multiple collimating lenses Z5 will result in a large Z Block size.

[0004] To combine and split multiple wavelengths using an arrayed waveguide grating (AWG), a high-refractive-index arrayed waveguide A1, an input arrayed waveguide grating A2, and an output arrayed waveguide grating A3 must be designed on a silicon substrate. The fixed length difference between adjacent waveguides in the arrayed waveguide A1 allows optical signals with different wavefront tilts to be coupled to different output terminals A4. However, the input arrayed waveguide grating A2 still needs to transmit the optical signal through fiber Z4 and collimating lens Z5, and then through the arrayed waveguide A1 to the output arrayed waveguide grating A3. Multiple wavelengths are combined through the input arrayed waveguide grating A2 and split through the output arrayed waveguide grating A3. However, the high splitting loss and poor channel isolation of the input and output arrayed waveguide gratings A2 and A3 can lead to optical crosstalk. Furthermore, the design of the input and output arrayed waveguide gratings A2 and A3 is quite complex.

[0005] Therefore, the technical challenges to be addressed in this application are how to overcome the practical problems encountered, reduce the overall structure volume, reduce complex coating structures, and reduce optical crosstalk. Summary of the Invention

[0006] In view of the problems in the related technologies, the purpose of this application is to reduce the overall structure, reduce the complexity of the coating structure and reduce the use of collimating lenses. Therefore, this application solves the problems in the related technologies by changing the structure and the optical path.

[0007] According to the purpose of this application, a volumetric holophotograph for use in a CWDM beam splitter is provided, comprising:

[0008] A light source, used to provide a laser beam;

[0009] A first lens has a first light-incident side and a first light-outcident side. The laser beam enters through the first light-incident side of the first lens, wherein the first lens expands the laser beam to form an expanded laser beam.

[0010] At least one first single-wavelength volumetric optical element (VHOE) is stacked on the first light-emitting side of the first lens. After the expanded laser beam passes through the stacked at least one first single-wavelength volumetric optical element, it will have different diffraction angles, thus converting the expanded laser beam into multiple plane waves with different diffraction angles according to different wavelengths.

[0011] The second lens has a second light-incident side and a second light-outcident side. The second light-incident side of the second lens is located on the side of the first single-wavelength volume whole image that is away from the first lens. The multiple plane waves enter from the second light-incident side of the second lens and are separated from each other by the multiple plane waves with different diffraction angles through the second lens. The plane wave with a diffraction angle of 0 degrees can be directly emitted perpendicularly from the second light-outcident side of the second lens.

[0012] At least one second single-wavelength volumetric total image is arranged parallel to the second light-emitting side of the second lens. By arranging the second single-wavelength volumetric total image in parallel, the diffraction angle of plane waves of different wavelengths can be adjusted so that the plane waves can be emitted perpendicularly.

[0013] In one embodiment, the first single-wavelength volumetric hologram or the second single-wavelength volumetric hologram is formed by taking pictures using a holographic transmission optical architecture. At least one interference fringe is established on the first single-wavelength volumetric hologram or the second single-wavelength volumetric hologram using the holographic transmission optical architecture. The interference fringe completely records the wavelength, angle and vector waveform of the incident light. When coupled with a laser beam of the same wavelength and the same incident angle, the records of these first single-wavelength volumetric holograms or these second single-wavelength volumetric holograms can be reproduced.

[0014] In one embodiment, the light source is transmitted through a single-film optical fiber with a numerical aperture of 0.22.

[0015] In one embodiment, the first incident light side of the first lens is provided with an anti-reflective coating.

[0016] In one embodiment, the first lens has a thickness, and the laser beam is expanded in diameter by passing through the thickness of the first lens, wherein the thickness is approximately 4 mm to 5 mm, more preferably, the thickness of the first lens is 4.5 mm and the diameter of the laser beam after expansion is approximately 2 mm.

[0017] In one embodiment, the second lens has a thickness, through which multiple plane waves of different wavelengths pass to adjust the distance between the multiple plane waves, wherein the thickness of the second lens is approximately 5 mm and the distance between the multiple plane waves is approximately 2 mm.

[0018] The laser beam from the light source passes sequentially through a first lens, at least one first single-wavelength volumetric tomographic image, and a second lens, or may further penetrate the second single-wavelength volumetric tomographic image. The first lens has a thickness that expands the laser beam to form an expanded laser beam. The expanded laser beam is diffracted at different angles according to different wavelengths by at least one stacked first single-wavelength volumetric tomographic image and converted into multiple plane waves. The multiple plane waves enter the second lens, and the spacing between the multiple plane waves is adjusted by the second lens. The multiple plane waves enter at least one parallel second single-wavelength volumetric tomographic image to adjust the diffraction angle, so that the multiple plane waves can be emitted perpendicularly. Among them, the plane wave with a diffraction angle of 0 degrees can be emitted perpendicularly without passing through the second single-wavelength volumetric tomographic image. This application reduces the use of collimating lenses and achieves the effect of reducing volume by expanding the laser beam, diverging it into plane waves, adjusting the spacing between the plane waves, and adjusting the diffraction angle so that plane waves of different wavelengths can be emitted perpendicularly. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the Z-block used for spectral dispersion in related technologies.

[0020] Figure 2 This is a schematic diagram illustrating the use of AWG for combining and spectroscopic applications in related technologies.

[0021] Figure 3 This is a schematic diagram of a light source paired with a single-wavelength volumetric holograph in an embodiment of this application.

[0022] Figure 4 This is a schematic diagram of the laser beam expanding action according to an embodiment of this application.

[0023] Figure 5 This is a schematic diagram of the holographic transmission optical architecture used to fabricate a volumetric hologram in an embodiment of this application.

[0024] Figure 6(a) is a schematic diagram of the Bragg condition.

[0025] Figure 6(b) is a schematic diagram of a plane wave passing through a second single-wavelength volumetric panorama and obeying the Bragg condition in an embodiment of this application.

[0026] Figure 7 This is a schematic diagram simulating the efficiency after spectral dispersion in an embodiment of this application.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1: Light source

[0029] 11: Laser beam

[0030] 12: Expanding laser beam

[0031] 121-124: Plane waves

[0032] 2: First lens

[0033] 21: Anti-reflective coating

[0034] 3: First single-wavelength volumetric holograph

[0035] 4: Second lens

[0036] 5: Second single-wavelength volumetric holograph

[0037] A1: Array waveguide

[0038] A2: Input array waveguide grating

[0039] A3: Output array waveguide grating

[0040] A4: Output terminal

[0041] Z1: Orthorhombic prism

[0042] Z2: Total Reflection Coating

[0043] Z3: Broadband Filter

[0044] Z4: Fiber Optic

[0045] Z5: Collimating Lens

[0046] O1: Light source

[0047] O11: Reference light

[0048] O12: Object light

[0049] O2: Optical beam expander

[0050] O3: Shutter

[0051] O4: Half-wave plate

[0052] O5: Spectrometer

[0053] O6: Aperture

[0054] O7: Face Mirror

[0055] O8: Photosensitive material Detailed Implementation

[0056] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0057] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application's specification are for illustrative purposes only and do not represent the only possible implementation.

[0058] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" or "plural" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0059] In this application, unless otherwise expressly specified and limited, the terms "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, the terms "above," "over," and "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. The terms "above," "over," and "on top" the second feature can also mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0060] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly known to one of ordinary skill in the art to which this application belongs. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items.

[0061] Please see Figure 3 As shown in the embodiment of this application, a volumetric total imager for use in a CWDM beam splitter includes: a light source 1, a first lens 2, at least one first single-wavelength volumetric total imager 3, a second lens 4, and at least one second single-wavelength volumetric total imager 5.

[0062] The light source 1 provides a laser beam 11, and the transmission medium of the light source 1 is a single-film optical fiber with a numerical aperture (NA) of 0.22, through which the laser beam 11 is transmitted.

[0063] The first lens 2 has a first light-incident side and a first light-outcident side. After the laser beam 11 is emitted from the single-film optical fiber, it enters through the first light-incident side of the first lens 2. Since the first lens 2 has a thickness T, after the laser beam 11 enters the first lens 2, the laser beam 11 will gradually expand to form an expanded laser beam 12.

[0064] The thickness T of the first lens 2 is approximately 4mm to 5mm and the first lens 2 is made of glass. After the laser beam 11 enters the first lens 2, the optical path length of the laser beam 11 will be equal to the thickness T of the first lens 2. The laser beam 11 will gradually expand after passing through the first lens 2. After the laser beam 11 penetrates the first lens 2, the laser beam 11 of the first lens 2 will form an expanded laser beam 12, and the diameter of the expanded laser beam 12 will reach a width of about 2mm.

[0065] Please refer to the following: Figure 4 To ensure that the single-film optical fiber with a numerical aperture of 0.22 achieves a beam width of approximately 2 mm through beam expansion, the numerical aperture of 0.22 can be calculated using the following formula (refer to Equation 1) to determine its diffraction angle as 12.7. ° ,

[0066]

[0067] Where ∝ is the diffraction angle.

[0068] When NA=0.22, ∝=12.7 ° .

[0069] In addition, the formula for expanding the light source beam (refer to Equation 2) is as follows:

[0070]

[0071] Where d is the width of the expanded laser beam 12, and T is the thickness of the first lens 2. Therefore, when the thickness T of the first lens 2 is 4mm to 5mm, the width of the expanded laser beam 12 will be approximately 1.8mm to 2.25mm. In order to obtain a width of approximately 2mm for the expanded laser beam 12, the thickness T of the first lens 2 needs to be approximately 4.5mm. The numerical aperture, the thickness T of the first lens 2, and the width of the expanded laser beam 12 are merely examples and are not intended to limit the application of these parameters.

[0072] Multiple first single-wavelength volumetric total images 3 are stacked on the first light-emitting side of the first lens 2. That is, the beam-expanding laser beam 12 needs to penetrate multiple first single-wavelength volumetric total images 3. Light of different wavelengths in the beam-expanding laser beam 12 will be converted into multiple plane waves with different diffraction angles (i.e., plane wave 121, plane wave 122, plane wave 123 or plane wave 124 shown in the figure) by multiple first single-wavelength volumetric total images 3, so that the multiple plane waves are split into different diffraction angles (e.g., 0 degrees, 22 degrees, 39 degrees or 50 degrees, but not limited to this).

[0073] The second lens 4 has a second light-incident side and a second light-outcident side. The second light-incident side of the second lens 4 is located on the side of the first single-wavelength volumetric image 3 away from the first lens 2. Multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure) have different diffraction angles. Therefore, multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure) will enter the second light-incident side of the second lens 4 from different positions. Since the second lens 4 has a thickness, when multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure) with different diffraction angles travel in the second lens 4, the distance between multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure) will gradually increase.

[0074] The second lens 4 has a thickness of approximately 5 mm and is made of glass. After multiple plane waves (i.e., plane waves 121, 122, 123, or 124 as shown in the figure) enter the second lens 4, the optical path length of each plane wave will be the diffraction angle of the plane waves (i.e., plane waves 121, 122, 123, or 124 as shown in the figure) divided by the thickness of the second lens 4. The plane wave 121, with a diffraction angle of 0 degrees, will be emitted perpendicularly from the second light-emitting side of the second lens 4. When multiple plane waves (i.e., plane waves 121, 122, 123, and 124 shown in the figure) pass through the second lens 4, the spacing between the multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure) will change due to the difference in diffraction angle. Therefore, after the multiple plane waves (i.e., plane waves 121, 122, 123, and 124 shown in the figure) pass through the second lens 4 with a thickness of approximately 5 mm, the spacing between the multiple plane waves (i.e., plane waves 121, 122, 123, and 124 shown in the figure) will be approximately 2 mm.

[0075] When a first single-wavelength volumetric hologram 3 or a second single-wavelength volumetric hologram 5 is captured using a holographic transmission optical architecture to generate multiple interference fringes, these interference fringes completely record the wavelength, angle, and vector waveform of the incident light. When coupled with laser beams of the same wavelength and the same incident angle, the records of multiple first single-wavelength volumetric holograms 3 or multiple second single-wavelength volumetric holograms 5 can be reproduced. Therefore, by using light sources of different wavelengths with different incident angles, the reconstructed light sources of different wavelengths can have corresponding diffraction angles. Furthermore, by using light sources of different wavelengths with different diffraction angles, multiple plane waves (i.e., the plane waves shown in the figure) can be reconstructed. Plane waves 121, 122, 123, or 124 are spaced apart from each other. For example, plane wave 121 is photographed with a wavelength of 1270nm at an incident angle of 0 degrees. When the wavelength of plane wave 121 is 1270nm, it will diffract at 0 degrees during reconstruction. However, plane wave 122 is photographed with a wavelength of 1290nm. In order to maintain a distance of 2mm between it and plane wave 121 with a wavelength of 1270nm, the incident angle of plane wave 122 with a wavelength of 1290nm must be 22 degrees so that it can diffract at 22 degrees after reconstruction. The formula (refer to (Equation 3)) is as follows:

[0076]

[0077] When the plane wave 121 spacing is 2mm and the thickness of the second lens is 5mm,

[0078] Furthermore, when the wavelength of the plane wave 123 is 1310nm during imaging and the distance between it and the plane wave 121 is 4mm, and the thickness of the second lens is 5mm, substituting into (Equation 3) yields the following result:

[0079] 4mm = 5mm × tanθ;

[0080] θ (diffraction angle) = 38.6598 ° θ (diffraction angle) .

[0081] The diffraction angle of plane wave 121 and plane wave 123 is approximately 39 degrees. Therefore, diffraction at 39 degrees during imaging and reconstruction will maintain the spacing between plane wave 121 and plane wave 122 or between plane wave 122 and plane wave 123 after passing through multiple second single-wavelength volumetric whole images 5 at 2 mm.

[0082] Similarly, it can be deduced that the wavelength of the plane wave 124 is 1330nm and the diffraction angle is 50 degrees when it is captured. Therefore, only by reconstructing with 50-degree diffraction can the distance between the plane waves 123 and 124 after passing through multiple second single-wavelength volumetric full-image films 5 be maintained at 2mm. Substituting into (Equation 3) as follows:

[0083] 6mm = 5mm × tanθ;

[0084] θ (diffraction angle) .

[0085] It should be noted that this application is not limited to the above-mentioned combinations of wavelengths and incident or diffraction angles, or other combinations of wavelengths and / or incident or diffraction angles.

[0086] Multiple second single-wavelength volume total images 5 are arranged parallel to each other on the second light-emitting side of the second lens 4 and the multiple second single-wavelength volume total images 5 do not overlap each other. The multiple second single-wavelength volume total images 5 adjust their diffraction angle for plane wave 122, plane wave 123 or plane wave 124 so that plane wave 122, plane wave 123 or plane wave 124 can be emitted perpendicularly.

[0087] Please refer to Figure 6(a). The multiple first single-wavelength volumetric holograms 3 and the multiple second single-wavelength volumetric holograms 5 all obey the Bragg condition. The following uses multiple second single-wavelength volumetric whole images 5 as examples to illustrate this. For multiple plane waves (i.e., plane wave 121, plane wave 122, plane wave 123, or plane wave 124 shown in the figure), this The vectors generated by the interference fringes of multiple second single-wavelength volume holographs 5 The vectors of multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure) after passing through multiple interference fringes are transmitted. Therefore, multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure) pass through multiple second single-wavelength volume whole images 5 corresponding to different interference fringes (not shown in the figure) so that multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure) combine with the vectors of multiple interference fringes to form a vertically emitted plane wave, as shown in Figure 6(b).

[0088] Since the diffraction angle of the plane wave 121 is already 0 degrees, the plane wave 121 can be directly emitted vertically through the second lens 4. Therefore, the diffraction angle can be adjusted by passing through or not passing through the second single-wavelength volume total image 5. By passing through the second single-wavelength volume total image 5, the incident angle and diffraction angle of the plane wave 121 are both 0 degrees, so that the plane wave 121 is maintained to be emitted vertically.

[0089] The first incident light side of the first lens 2 is further provided with an anti-reflection coating 21. The anti-reflection coating 21 removes the reflected light generated by the reflection of the laser beam 11 by forming a destructive interference with the laser beam 11. This allows the present application to further reduce the influence of optical crosstalk. In addition, since the anti-reflection coating 21 only needs to be designed for the laser beam 1, it does not need to be designed for various wavelengths like the Z block to achieve total reflection. Therefore, it can reduce the complexity of the coating structure.

[0090] Please see Figure 5 As shown, the holographic transmission optical architecture mainly comprises a light source O1, a beam expander O2, a shutter O3, at least one half-wave plate O4, a beam splitter O5, at least one aperture O6, at least one mirror O7, and a photosensitive material O8. The light source O1 is expanded by the beam expander O2, and the exposure time is controlled by the shutter O3. The half-wave plate O4 creates a phase difference in the light source O1, and the beam splitter O5 generates a reference light O11 and a target light O12. The reference light O11 is then orthogonal to the target light O12 by the half-wave plate O4. The reference light O11 passes through the aperture O6 and... The mirror O7 projects onto the photosensitive material O8, while the target light O12 is projected onto the photosensitive material O8 through the mirror O7 and the aperture O6. Multiple apertures O6 are used to filter edge noise to avoid affecting the recorded information on the photosensitive material O8. The photosensitive material O8 can simultaneously record the wavelength, angle, and vector waveform of the reference light O11 and the target light O12 to form the first single-wavelength volumetric hologram 3 or the second single-wavelength volumetric hologram 5. However, the first single-wavelength volumetric hologram 3 or the second single-wavelength volumetric hologram 5 of this application is not limited to the fabrication of a holographic transmission optical architecture and can also be fabricated in other ways.

[0091] The laser beam 11 from the light source 1 passes successively through the first lens 2, at least one first single-wavelength volumetric tomographic image 3, and the second lens 4, or may further penetrate the second single-wavelength volumetric tomographic image 5. The first lens 2 has a thickness T, which expands the laser beam 11 to form the expanded laser beam 12. The expanded laser beam 12 is diffracted by multiple stacked first single-wavelength volumetric tomographic images 3 according to different wavelengths and converted into multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure). The multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure) enter the second lens 4, and the diffraction angle of the multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure) is adjusted by the thickness of the second lens 4 and the difference in the diffraction angle of the multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure). The spacing between multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure) and the diffraction angles of the multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure) are adjusted so that the multiple plane waves (i.e., plane waves 121, 122, 123, or 124 shown in the figure) can be emitted perpendicularly. Among them, plane wave 121 with a diffraction angle of 0 degrees can selectively pass through or not pass through the second single-wavelength volume total image 5 before being emitted perpendicularly. This application reduces the use of collimating lenses to achieve the effect of reducing volume by expanding the laser beam 11, diverging it into plane waves, adjusting the spacing between the plane waves, and adjusting the diffraction angle so that multiple plane waves of different wavelengths (i.e., plane waves 121, 122, 123, or 124 shown in the figure) can be emitted perpendicularly. In addition, please refer to Figure 7 As shown, the results of a test plane wave with a wavelength of 1300nm simulated by this application are presented. The efficiency at 1290nm and 1310nm is only -25dB, which indicates that this application has good channel isolation.

[0092] This application can also replicate multiple first single-wavelength volumetric holograms 3 or multiple second single-wavelength volumetric holograms 5 using master film replication technology. Multiple first single-wavelength volumetric holograms 3 or multiple second single-wavelength volumetric holograms 5 are used as master films, and daughter films are attached above the master films. A laser beam with the same recording as the master film is incident perpendicularly from the daughter film direction to the master film. The laser beam penetrates the daughter film to the master film and generates diffraction light. The diffraction light interferes with the perpendicularly incident laser beam on the daughter film, and its interference fringes will be the same as those of the master film. Therefore, this application can achieve the effect of improving mass production through master film replication technology.

[0093] The foregoing detailed description is a specific description of feasible embodiments of this application. However, the foregoing embodiments are not intended to limit the scope of protection of the claims of this application. All equivalent implementations or modifications that do not depart from the spirit and meaning of this application should be included in the scope of protection of the claims of this application.

Claims

1. A volumetric holophotograph for use in a CWDM beam splitter assembly, characterized in that, include: A light source, used to provide a laser beam; A first lens has a first light-incident side and a first light-outcident side. The laser beam enters through the first light-incident side of the first lens, wherein the first lens expands the laser beam to form an expanded laser beam. At least one first single-wavelength volumetric total image is stacked on the first light-emitting side of the first lens. After the expanded laser beam passes through the stacked at least one first single-wavelength volumetric total image, it will have different diffraction angles, thus converting the expanded laser beam into multiple plane waves with different diffraction angles according to different wavelengths. The second lens has a second light-incident side and a second light-outcident side. The second light-incident side of the second lens is located on the side of the first single-wavelength volume whole image that is away from the first lens. The multiple plane waves enter from the second light-incident side of the second lens and are separated from each other by the multiple plane waves with different diffraction angles through the second lens. The plane wave with a diffraction angle of 0 degrees can be directly emitted perpendicularly from the second light-outcident side of the second lens. as well as The second lens has at least one second single-wavelength volumetric image plate arranged parallel to the second light-emitting side, which can adjust the diffraction angle for plane waves with different incident angles and different wavelengths, so that the plane waves can be emitted perpendicularly.

2. The volumetric holophotograph applied to a CWDM beam splitter according to claim 1, characterized in that, The light source is transmitted through a single-film optical fiber with a numerical aperture of 0.

22.

3. The volumetric holophotograph applied to a CWDM beam splitter according to claim 1, characterized in that, The first incident light side of the first lens is provided with an anti-reflective coating.

4. The volumetric holophotograph applied to a CWDM beam splitter according to claim 1, characterized in that, The first lens has a thickness, and the diameter of the laser beam after passing through the first lens is expanded to a width of 2 mm.

5. The volumetric holophotograph applied to a CWDM beam splitter according to claim 4, characterized in that, The thickness of the first lens is 4mm to 5mm.

6. The volumetric holophotograph applied to a CWDM beam splitter according to claim 5, characterized in that, The thickness of the first lens is 4.5 mm.

7. The volumetric holophotograph applied to a CWDM beam splitter according to claim 1, characterized in that, The second lens has a thickness of 5 mm, and the plurality of plane waves, which have different diffraction angles due to different wavelengths, are spaced 2 mm apart after passing through the second lens.

8. The volumetric holophotograph applied to a CWDM beam splitter according to claim 7, characterized in that, The wavelengths of the plane waves are 1270nm, 1290nm, 1310nm and 1330nm.

9. The volumetric holophotograph applied to a CWDM beam splitter according to claim 8, characterized in that, The diffraction angles corresponding to the multiple plane waves are 0 degrees, 22 degrees, 39 degrees and 50 degrees, respectively.

Images