All-fiber white light laser for laser display

Abstract

The invention provides an all-fiber white light laser for laser display. The all-fiber white light laser comprises a blue light pumping source; the blue light pumping source is connected with the resonant cavity assembly through the multimode tail fiber; a gain optical fiber is arranged in the resonant cavity assembly; after the pumping blue light excites the gain optical fiber, red laser and green laser are generated at the same time, and the red laser and the green laser are synthesized into white laser in the multimode output optical fiber with the residual pumping blue light. According to the white light fiber laser, an all-fiber structure is achieved, mixed white light of RGB three primary colors is obtained through a single gain fiber, and the white light fiber laser has the advantages of being high in conversion efficiency, simple in structure, easy to miniaturize and the like.

Description

Technical Field

[0001] The present application relates to the fields of laser display, laser lighting, and visible light wireless communication, and in particular to an all-fiber white light laser for laser display. Background Art

[0002] In recent years, in order to ease the tension of RF spectrum, Li-Fi technology has emerged. It uses light-emitting diodes (LEDs) as white light sources and can achieve high-speed communication while LED lighting. Although LED light sources have the advantages of high efficiency and long life, their luminous efficiency is limited by the "efficiency drop" effect. At the same time, due to the narrow direct modulation bandwidth, the high-speed performance is limited. In contrast, laser-based white light sources have high brightness, high energy efficiency, good beam directional characteristics, wide direct modulation bandwidth, and fast response speed, which better meets the needs of high-brightness solid-state lighting and high-speed, long-distance communication. In addition, white light laser sources can also be used as backlight sources in laser displays. Therefore, white light lasers are playing an increasingly important role in many fields such as lighting, indoor lighting and communication (Li-Fi), underwater communication, laser display, etc., and have attracted the attention of many researchers.

[0003] At present, there are three main ways to generate white light lasers:

[0004] 1. Use several independent lasers to generate RGB three primary colors or multi-color lasers to synthesize white light lasers. The multiple laser sources of this solution are usually individually processed and assembled separately, which is not easy to achieve miniaturization and integration, and the production cost is high.

[0005] 2. Use yellow fluorescent functional materials to convert blue laser into white light laser. The fluorescent functional materials in this scheme need to withstand high laser bombardment to produce high-brightness white light, which has high requirements for material technology, and the light collimation is weakened, and more fluorescent stray light is generated during the conversion.

[0006] 3. Generate supercontinuum spectrum through optical nonlinear effect to achieve white light laser. This solution usually requires the use of ultrafast laser as the fundamental frequency input light, which is expensive, has low conversion efficiency, and cannot adapt to miniaturization and integration application scenarios. In addition, the relative intensity of the spectrum generated by this solution is fixed, making it difficult to control the intensity of each component spectrum, and thus difficult to regulate the color of the emitted laser.

[0007] Therefore, an "integrated", high-efficiency white light laser that is easy to miniaturize and integrate and can output the three primary colors of RGB simultaneously has become the focus of researchers. The key difficulty lies in creating materials that can simultaneously and efficiently emit the three primary colors of RGB or multiple colors. Among them, semiconductor materials have the advantages of high efficiency, easy electrical injection and easy integration, and have always been the first choice for light-emitting materials. The traditional technical difficulty of this method is that the semiconductor lattices that emit different colors are mismatched, resulting in a decrease in the photoelectric quality of the crystal; secondly, semiconductor lasers have a "green gap", and the green light efficacy is low. At the same time, long-wavelength (red light) semiconductor materials absorb the light emitted by short-wavelength (blue light, green light) semiconductor materials, making it difficult to achieve simultaneous lasing of multiple colors. Nano-semiconductor materials that have emerged in recent years still have problems such as being difficult to obtain and expensive.

[0008] Rare earth ion-doped materials can produce abundant visible light wavelength transitions under the pumping of blue lasers, making an "integrated" white light laser possible. Compared with rare earth-doped crystal lasers with spatial structures and poor stability, down-conversion rare earth ion-doped fiber lasers can achieve an all-fiber structure through fiber coating technology and fiber grating preparation technology, and have significant advantages such as high efficiency, good stability, simple structure, and easy miniaturization.

[0009] Current related research has also made some progress. For example, by pumping holmium-praseodymium co-doped fluoride optical fiber with blue light to produce multi-wavelength fluorescence emission and then obtain white light fluorescence, which fully demonstrates the potential of rare-earth-doped white light fiber lasers.

[0010] Similarly, praseodymium-doped fluoride fiber can produce red and green light emissions under blue light pumping, and is an ideal choice for directly generating three primary colors of laser light to achieve white light laser.

[0011] In terms of laser display, compared with semiconductor laser light sources, the spectral width of fiber laser light sources expands more significantly with increasing power, has lower speckle contrast, and the image display is less affected by speckle noise.

[0012] In addition, Chinese patent application with publication number CN116031736A discloses a white hybrid laser light source based on visible light fiber laser, which has the following disadvantages: different wavelengths of laser light are generated by multiple gain fibers and then combined into white light, and the structure is too complex to be easily miniaturized. Summary of the invention

[0013] In order to solve the above technical problems, an all-fiber white light laser for laser display is proposed, comprising: a blue light pump source; the blue light pump source is connected to a resonant cavity assembly via a multimode pigtail; a gain fiber is arranged in the resonant cavity assembly; after the pump blue light excites the gain fiber, red and green lasers are generated simultaneously, and are synthesized into white light laser with the residual pump blue light in the multimode output fiber.

[0014] The above technical scheme provides an overall structure of an all-fiber white light laser for laser display. By connecting a blue light pump source, a resonant cavity assembly and a gain fiber, it realizes the function of lasing red light and green light and synthesizing white light with the pump blue light, thereby realizing an all-fiber white light laser that can be used for laser display and provides white light output.

[0015] Specifically, the blue light pump source is a semiconductor laser with a multi-mode pigtail: the blue light pump source is connected to the resonant cavity component through the multi-mode pigtail.

[0016] In the above technical solution, the blue light pump source adopts a semiconductor laser with its own multi-mode pigtail, and connects the resonant cavity component through the multi-mode pigtail, which ensures the effective transmission of the pump light, solves the connection problem between the blue light pump source and the resonant cavity component, and is conducive to the realization of an all-fiber structure.

[0017] Specifically, the resonant cavity component includes a first optical fiber end surface coating mirror coated on the multi-mode pigtail fiber and a second optical fiber end surface coating mirror coated on the multi-mode output optical fiber.

[0018] The above technical solution forms a resonant cavity component by coating a fiber end-face coated mirror on the multi-mode pigtail and the multi-mode output optical fiber, thereby providing necessary optical feedback for the generation of laser.

[0019] Specifically, the first optical fiber end face coated mirror is designed to have high transmittance in the blue light band, high reflectivity in the green light band, and high transmittance in the red light band.

[0020] In the above technical solution, the design of the first optical fiber end-face coated mirror makes the blue light band highly transparent, the green light band highly reflective, and the red light band highly transparent, which helps to realize laser oscillation and synthesis in specific bands, control the transmission and reflection of light in the resonant cavity, and promote the generation of red and green lasers.

[0021] Specifically, the second optical fiber end face coated mirror is designed to be highly reflective in the blue light band, partially reflective in the green light band, and highly transparent in the red light band.

[0022] In the above technical solution, the design of the second optical fiber end face coated mirror makes the blue light band highly reflective, the green light band partially reflective, and the red light band highly transparent, thereby adjusting the reflection and output of light in the resonant cavity, which is beneficial to the synthesis and output of white light.

[0023] Specifically, the resonant cavity component also includes: a copper sleeve; a multimode pigtail fiber connected to the input end of the gain optical fiber through the copper sleeve; and a multimode output optical fiber connected to the output end of the gain optical fiber through the copper sleeve.

[0024] In the above technical solution, the use of the copper sleeve ensures a low-loss connection between the optical fiber end-face coated mirror and the gain optical fiber, which is conducive to forming a compact all-fiber linear cavity structure for forming laser oscillation.

[0025] Specifically, the operating wavelength of the blue light pump source is 443nm and the maximum power is 60W.

[0026] The above technical solution stipulates the operating wavelength of the blue light pump source, and its high-power output provides an important basis for realizing high-power white light lasers.

[0027] Specifically, the gain optical fiber is a double-clad praseodymium fluoride-doped optical fiber.

[0028] In the above technical solution, the gain optical fiber adopts double-clad praseodymium fluoride-doped optical fiber, which helps to improve the conversion efficiency of the laser.

[0029] Specifically, it also includes: a multi-mode output optical fiber tail end; and a multi-mode output optical fiber tail end outputting white light laser.

[0030] In the above technical solution, the tail end of the multi-mode output optical fiber is precisely polished to facilitate the connection and use of the laser with other devices, and to provide an output interface for the laser to facilitate integration with external devices.

[0031] Compared with the prior art, the beneficial results of this application are:

[0032] 1. The present invention uses praseodymium-doped fluoride optical fiber as the gain medium, which is moderately priced and has good heat dissipation performance, without the need for an additional heat dissipation system;

[0033] 2. The present invention uses a single optical fiber and two optical fiber end-face coated mirrors to form laser resonance, realizing an all-optical fiber structure without any free space components, and has a simple structure and is easy to miniaturize;

[0034] 3. The red light, green light and residual pump blue light generated by the present invention are uniformly introduced into the core of the multimode optical fiber and mixed to form white light, which is finally output from the tail end of the multimode output optical fiber, and the operation is simple;

[0035] 4. The present invention can achieve a combination of red, green and blue primary color lasers with different power ratios to obtain white light lasers with different color temperatures by designing the film system of the optical fiber end face coating mirror and changing the optical fiber length. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate the embodiments and are used together with the description to explain the principles of the present application. It will be easy to recognize other embodiments and many expected advantages of the embodiments because they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale with each other. The same reference numerals refer to corresponding similar parts.

[0037] Figure 1is a schematic structural diagram of an all-fiber white light laser for laser display according to an embodiment of the present application;

[0038] Figure 2 is a film system curve of the first optical fiber end face coating of an all-fiber white light laser for laser display according to an embodiment of the present application;

[0039] Figure 3 is a film system curve of the coating on the second optical fiber end face of an all-fiber white light laser for laser display according to an embodiment of the present application;

[0040] Figure 4 is a spectrum diagram of mixed white light of an all-fiber white light laser for laser display according to an embodiment of the present application;

[0041] Figure 5 It is a schematic structural diagram of a coated mirror of an all-fiber white light laser for laser display according to an embodiment of the present application.

[0042] The meaning of the numbers in the figure are: 1. Blue light pump source; 2. Multimode pigtail; 3. Gain fiber; 4. Multimode output fiber; 5. Output multimode fiber tail; 6. Copper sleeve; 7. First fiber end face coating mirror; 8. Second fiber end face coating mirror. DETAILED DESCRIPTION

[0043] In the following detailed description, reference is made to the accompanying drawings, which form a part of the detailed description and are shown by illustrative specific embodiments in which the present application can be practiced. To this end, directional terms, such as "top", "bottom", "left", "right", "up", "down", etc., are used with reference to the orientation of the figures described. Because the components of the embodiments can be positioned in several different orientations, directional terms are used for the purpose of illustration and are by no means limiting. It should be understood that other embodiments may be utilized or logical changes may be made without departing from the scope of the present application. Therefore, the following detailed description should not be adopted in a limiting sense, and the scope of the present application is defined by the appended claims.

[0044] like Figure 1 As shown, an all-fiber white light laser for laser display includes: a blue light pump source 1; the blue light pump source 1 is connected to a resonant cavity assembly through a multimode pigtail 2; a gain fiber 3 is arranged in the resonant cavity assembly; after the pump blue light excites the gain fiber 3, red light and green light lasers are generated simultaneously, and are synthesized into white light laser with the residual pump blue light in the multimode output fiber 4.

[0045] It can be seen that the present application can realize the synthesis of three different wavelengths of RGB lasers only through a single gain optical fiber 3, thereby obtaining white light.

[0046] The blue light pump source 1 is a semiconductor laser with a multi-mode pigtail 2: the blue light pump source 1 is connected to the resonant cavity component through the multi-mode pigtail 2.

[0047] The resonant cavity assembly comprises a first optical fiber end surface coating mirror 7 coated on the multi-mode pigtail 2 and a second optical fiber end surface coating mirror 8 coated on the multi-mode output optical fiber.

[0048] The first optical fiber end face coating mirror 7 is designed to be highly transparent in the blue light band, highly reflective in the green light band, and highly transparent in the red light band.

[0049] The second optical fiber end face coating mirror 8 is designed to be highly reflective in the blue light band, partially reflective in the green light band, and highly transparent in the red light band.

[0050] The resonant cavity assembly also includes: a copper sleeve 6; the multimode pigtail 2 is connected to the input end of the gain optical fiber 3 through the copper sleeve 6; and the multimode output optical fiber 4 is connected to the output end of the gain optical fiber 3 through the copper sleeve 6.

[0051] The operating wavelength of the blue light pump source 1 is 443 nm, and the maximum power is 60 W.

[0052] Gain fiber 3 double-clad praseodymium fluoride-doped fiber.

[0053] It also includes: a multi-mode output optical fiber 4 tail end; and a multi-mode output optical fiber tail end outputting white light laser.

[0054] The multimode pigtail fiber 2 and the multimode output optical fiber 3 are the same type of optical fiber, both of which are quartz optical fibers with a core size of 105 μm.

[0055] In this embodiment, the gain fiber 3 is a double-clad praseodymium fluoride-doped fiber. 3+ : ZBLAN) optical fiber, the core diameter of the optical fiber is 7.5μm, and the inner cladding has a double D-shaped profile with a diameter of 115×125μm. From the energy level point of view, Pr 3+ The ground state energy level of an ion 3 H4 absorbs 441nm pump laser to 3 P2 energy level, 3 P2 has no radiation transition to 3 P1 / 3 P0, 3 P1→ 3 H5 produces 520.9nm green light, 3 P0→ 3 F2 produces 635.5nm red light.

[0056] In this embodiment, the first optical fiber end face coating mirror 7 and the second optical fiber end face coating mirror 8 are dielectric films coated on the end faces of the multimode pigtail 2 and the multimode output optical fiber 3 using ion beam assisted evaporation coating technology. The reflectivity of the coating mirror in different bands of visible light can be controlled by film layer design. The first optical fiber end face coating mirror 7 and the second optical fiber end face coating mirror 8 constitute the resonance of green light and red light.

[0057] Furthermore, the pump blue light enters the resonant cavity through the first fiber end surface coated mirror 7 with high transparency to blue light, and excites the gain fiber 3. The design of the first fiber end surface coated mirror 7 and the second fiber end surface coated mirror 8 allows the green light to obtain more gain feedback, thereby competing with the red light with stronger gain, and realizing the simultaneous generation of red and green lasers.

[0058] Specifically, the first optical fiber end face coating mirror 7 is butted against the input end of the gain optical fiber 3 through the copper sleeve 6 , and the second optical fiber end face coating mirror 8 is butted against the output end of the gain optical fiber 3 through the copper sleeve 6 .

[0059] Specifically, the first optical fiber end face coating mirror 7 coated on the multimode pigtail 2 is designed to have a transmittance greater than 95% in the blue light band, a reflectance greater than 98% in the green light band, and a transmittance greater than 95% in the red light band.

[0060] Specifically, the second optical fiber end face coating mirror 8 coated on the multimode output optical fiber 4 is designed to have a reflectivity of about 95% in the blue light band, a reflectivity of about 60% in the green light band, and a transmittance of more than 95% in the red light band. The second optical fiber end face coating mirror 8 is designed to be highly reflective of blue light, which can make full use of blue light pumping and improve efficiency, while transmitting a small amount of residual blue light.

[0061] More specifically, Figure 5 As shown, in a specific embodiment, the first optical fiber end face coating mirror 7 and the first optical fiber end face coating mirror 8 are made by alternately stacking Ta2O5 layers and SiO2 layers with different thicknesses.

[0062] In this embodiment, the specific thickness of the Ta2O5 layer and the SiO2 layer in the first optical fiber end face coating mirror 8 is 177nm-25nm-145nm-33nm-104nm-49nm-58nm-71nm-119nm-25nm-74nm-49nm-84nm-25nm-92nm-48nm-81nm-47nm-66nm-53nm-83nm-26nm-114nm-25nm-92nm-40nm-66nm-25nm.

[0063] Furthermore, the red light, green light laser generated by the gain fiber 3 and the residual pump blue light laser are transmitted in the core of the multimode output fiber 4 and mixed into white light, and finally output out of the cavity from the multimode output fiber tail end 5 .

[0064] The present invention uses praseodymium-doped fluoride optical fiber as the gain medium, and the optical fiber has good heat dissipation performance and does not require an additional heat dissipation system. A single optical fiber and two optical fiber end-face coated mirrors are used to form the resonance of the laser, realizing an all-optical fiber structure without any free space components, and the structure is simple and easy to miniaturize.

[0065] The RGB three-primary color lasers are mixed in the core of the multimode optical fiber to form white light, which is finally output from the tail end of the multimode output optical fiber, and the operation is simple. The present invention can achieve a combination of red, green and blue three-primary color lasers with different power ratios by designing the film system of the optical fiber end face coating mirror and changing the optical fiber length, thereby obtaining white light lasers with different color temperatures.

[0066] Obviously, those skilled in the art can make various modifications and changes to the embodiments of the present application without departing from the spirit and scope of the present application. In this way, if these modifications and changes are within the scope of the claims of the present application and their equivalents, the present application is also intended to cover these modifications and changes. The word "comprising" does not exclude the presence of other elements or steps not listed in the claims. The simple fact that certain measures are recorded in mutually different dependent claims does not indicate that the combination of these measures cannot be used to profit. Any figure mark in the claims should not be considered to limit the scope.

Claims

1. An all-fiber white light laser for laser display, characterized in that: include: Blue light pump source; The blue light pump source is connected to the resonant cavity component through a multimode pigtail; a gain fiber is arranged in the resonant cavity component; the blue light pump source generates pump blue light and simultaneously generates red light and green light laser after being excited by the gain fiber, and is synthesized into white light laser with the residual pump blue light in the multimode output fiber.

2. The all-fiber white light laser for laser display according to claim 1, characterized in that: The blue light pump source is a semiconductor laser with a multi-mode pigtail: the blue light pump source is connected to the resonant cavity component through the multi-mode pigtail.

3. The all-fiber white light laser for laser display according to claim 2, characterized in that: The resonant cavity component comprises a first optical fiber end face coating mirror plated on the multi-mode pigtail and a second optical fiber end face coating mirror plated on the multi-mode output optical fiber.

4. The all-fiber white light laser for laser display according to claim 3, characterized in that: The first optical fiber end face coating mirror is designed to have high transmittance in the blue light band, high reflectance in the green light band, and high transmittance in the red light band.

5. The all-fiber white light laser for laser display according to claim 3, characterized in that: The second optical fiber end face coating mirror is designed to be highly reflective in the blue light band, partially reflective in the green light band, and highly transparent in the red light band.

6. The all-fiber white light laser for laser display according to claim 3, characterized in that: The resonant cavity component further includes: a copper sleeve; the multimode pigtail is connected to the input end of the gain optical fiber through the copper sleeve; and the multimode output optical fiber is connected to the output end of the gain optical fiber through the copper sleeve.

7. The all-fiber white light laser for laser display according to claim 1, characterized in that: Also includes: Multimode output fiber tail end; The multi-mode output optical fiber tail end is configured to output a synthesized white light laser.

8. An all-fiber white light laser for laser display according to any one of claims 1 to 7, characterized in that: The working wavelength of the blue light pump source is 443nm, and the maximum power is 60W.

9. An all-fiber white light laser for laser display according to any one of claims 1 to 7, characterized in that: The gain optical fiber is a double-clad praseodymium fluoride-doped optical fiber.

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