A fiber interference filter based on multi-core optical fiber

Abstract

The present invention discloses an optical fiber interference filter based on multi-core optical fiber, which belongs to the technical field of optical fiber filter devices. An optical fiber interference filter based on multi-core optical fiber is composed of a beam splitter, a beam combiner and multiple sections of multi-core optical fiber; the beam splitter and the beam combiner tail fibers are both single-mode optical fibers. The present invention adopts the above-mentioned optical fiber interference filter based on multi-core optical fiber, and utilizes the interference of light transmitted in the optical fiber to select a specific wavelength. It does not require expensive coating equipment, has flexible wavelength selection, and has low device cost. In addition, wavelength selection is realized directly on the optical fiber, and no special optical fiber integration process is required, which is convenient to implement.

Description

Technical Field

[0001] The invention relates to the technical field of optical fiber filter devices, and in particular to an optical fiber interference filter based on multi-core optical fibers. Background Art

[0002] Fiber optic filter is a wavelength selective device that can select or filter out specific wavelengths of light transmitted in an optical fiber. It has important applications in fiber lasers, wavelength division multiplexing fiber optic communications, frequency division multiplexing fiber optic communications, fiber optic sensors, and spectral testing.

[0003] The current implementation method of optical fiber filters is generally to coat a thin film of different thicknesses on a substrate, which can increase the transmittance of a specific wavelength and increase the reflection of other wavelengths, and then package the coated substrate with the optical fiber pigtail together.

[0004] However, for filters of different wavelengths, thin films of different thicknesses need to be strictly designed and formed, the wavelength selection is not flexible, and the coating equipment is expensive and has high environmental requirements, making this traditional method costly and complex.

[0005] Therefore, in order to solve the problems of inflexible wavelength selection, complicated process and high cost of existing optical fiber filters, the present invention proposes an optical fiber interference filter based on multi-core optical fiber. Summary of the invention

[0006] The purpose of the present invention is to provide an optical fiber interference filter based on multi-core optical fiber, which utilizes the interference of light transmitted in the optical fiber to select a specific wavelength, does not require expensive coating equipment, has flexible wavelength selection, low device cost, and realizes wavelength selection directly on the optical fiber, does not require special optical fiber integration technology, and is easy to implement.

[0007] To achieve the above objectives, the present invention provides a fiber interference filter based on multi-core optical fiber, which is composed of a beam splitter, a beam combiner and multiple sections of multi-core optical fiber; the beam splitter and the beam combiner pigtails are both single-mode optical fibers.

[0008] Preferably, the beam splitter is used to split the light transmitted in the optical fiber into multiple beams; and the beam combiner is used to couple the split multiple beams of light to the same optical fiber, namely, the pigtail of the beam combiner.

[0009] Preferably, of the multiple sections of multi-core optical fiber, one end of each section of multi-core optical fiber is connected to the pigtail of the beam splitter, and the other end is connected to the pigtail of the beam combiner.

[0010] Preferably, the multi-core optical fiber supports the transmission of two modes of light. When light enters the multi-core optical fiber from the pigtail of the beam splitter, two modes of light are excited. The two modes of light pass through the multi-core optical fiber and are coupled to the pigtail of the beam combiner.

[0011] Preferably, the two modes of light undergo different optical paths when transmitted in the multi-core optical fiber, and they interfere with each other in the pigtail of the combiner. The interference enhancement wavelength and free spectral range in the interference curve are related to the length of the multi-core optical fiber.

[0012] Preferably, the multiple sections of multi-core optical fiber perform interference enhancement at the designed wavelength; the multiple sections of multi-core optical fiber have different lengths, and the optical paths of the two mode lights in different multi-core optical fibers are different, so that the free spectral ranges of the interference curves after passing through different multi-core optical fibers are different.

[0013] Therefore, the present invention adopts the above-mentioned optical fiber interference filter based on multi-core optical fiber, utilizes the interference of light transmitted in the optical fiber to select a specific wavelength, does not require expensive coating equipment, has flexible wavelength selection, low device cost, and realizes wavelength selection directly on the optical fiber, does not require special optical fiber integration technology, and is easy to implement.

[0014] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of an optical fiber filter based on multi-core optical fiber;

[0016] Figure 2 It is an embodiment: an optical fiber interference filter based on multi-core optical fiber;

[0017] Figure 3 It is the transmission curve after passing through each section of multi-core optical fiber and the total transmission curve obtained by simulation.

[0018] In the figure:

[0019] 1. The first section of multi-core optical fiber; 2. The second section of multi-core optical fiber; 3. The third section of multi-core optical fiber; 4. The fourth section of multi-core optical fiber; 5. The fifth section of multi-core optical fiber; 6. The sixth section of multi-core optical fiber; 7. The seventh section of multi-core optical fiber; 8. 1×7 beam splitter; 9. 1×7 beam combiner. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not intended to limit the embodiments of the present invention. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions.

[0021] It should be noted that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or server that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products or devices.

[0022] Like reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0023] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0024] As shown in Figure 1, a fiber interference filter based on multi-core optical fiber, when broadband light passes through the filter, only light of the designed wavelength can pass through, and light of other wavelengths is filtered out. The present invention provides a fiber interference filter based on multi-core optical fiber, which is composed of a beam splitter, a beam combiner and multiple sections of multi-core optical fiber; the beam splitter and the beam combiner pigtail are both single-mode optical fibers. The beam splitter is used to divide the light transmitted in the optical fiber into multiple beams (≥3 beams); the beam combiner is used to couple the separated multiple beams of light to the same optical fiber, that is, the pigtail of the beam combiner. In the multiple sections of multi-core optical fiber, one end of each section of the multi-core optical fiber is connected to the pigtail of the beam splitter, and the other end is connected to the pigtail of the beam combiner. In the multi-core optical fiber, the transmission of two modes of light is supported. When the light enters the multi-core optical fiber from the pigtail of the beam splitter, two modes of light are excited. The two modes of light pass through the multi-core optical fiber and are coupled to the pigtail of the beam combiner. When the two modes of light are transmitted in the multi-core optical fiber, they experience different optical paths, and they interfere in the tail fiber of the beam combiner. The interference enhancement wavelength and free spectral range in the interference curve are related to the length of the multi-core optical fiber. The multiple sections of multi-core optical fiber have interference enhancement at the design wavelength; the multiple sections of multi-core optical fiber have different lengths, and the optical paths of the two modes of light in different multi-core optical fibers are different, so that the free spectral ranges of the interference curves after passing through different multi-core optical fibers are different. The spectra passing through each section of the multi-core optical fiber are superimposed to obtain the required transmission spectrum.

[0025] Example

[0026] like Figure 2As shown, a fiber interference filter based on multi-core optical fiber is composed of a 1×7 beam splitter 8, a 1×7 beam combiner 9 and 7 sections of multi-core optical fiber. The pigtails of the 1×7 beam splitter 8 and the 1×7 beam combiner 9 are both single-mode optical fibers with only one core. The 1×7 beam splitter 8 is used to split the light transmitted in the optical fiber into 7 beams; the 1×7 beam combiner 9 is used to couple the 7 separated beams of light to the same optical fiber, that is, the pigtail of the beam combiner. The multiple sections of multi-core optical fiber, one end of each section of the multi-core optical fiber is connected to the pigtail of the 1×7 beam splitter 8, and the other end is connected to the pigtail of the 1×7 beam combiner 9. The multi-core optical fiber supports the transmission of two modes of light. When the light enters the multi-core optical fiber from the pigtail of the beam splitter, two modes of light are excited. The two modes of light are coupled to the pigtail of the beam combiner through the multi-core optical fiber. When the two modes of light are transmitted in the multi-core optical fiber, they experience different optical paths, and they interfere in the tail fiber of the combiner. The interference enhancement wavelength and free spectral range in the interference curve are related to the length of the multi-core optical fiber. The seven sections of multi-core optical fiber have enhanced interference at the design wavelength; the lengths of the multiple sections of multi-core optical fiber are different, and the optical paths of the two modes of light in different multi-core optical fibers are different, so that the free spectral ranges of the interference curves after passing through different multi-core optical fibers are different. The spectra passing through the seven sections of multi-core optical fiber are superimposed to obtain the required transmission spectrum.

[0027] like Figure 3 As shown in the figure, when the design wavelength of the filter is 1033nm, the transmission curves obtained by simulation after passing through 7 sections of multi-core optical fiber and the transmission curves after superposition of each transmission curve. Curves 1, 2, 3, 4, 5, 6, and 7 are the transmission spectra of the first section of multi-core optical fiber 1, the second section of multi-core optical fiber 2, the third section of multi-core optical fiber 3, the fourth section of multi-core optical fiber 4, the fifth section of multi-core optical fiber 5, the sixth section of multi-core optical fiber 6, and the seventh section of multi-core optical fiber 7 when a broadband light source is incident. The lengths of the 7 sections of multi-core optical fiber are different, and the free spectral ranges of each transmission curve are also different, but they are all interfered and enhanced at the design wavelength of 1033nm. Among them, curve 8 is the result of the superposition of curves 1 to 7, that is, the total transmission curve of the designed filter. Light near the design wavelength of 1033nm can be transmitted, while light of other wavelengths is suppressed.

[0028] Therefore, the present invention adopts the above-mentioned optical fiber interference filter based on multi-core optical fiber, utilizes the interference of light transmitted in the optical fiber to select a specific wavelength, does not require expensive coating equipment, has flexible wavelength selection, low device cost, and realizes wavelength selection directly on the optical fiber, does not require special optical fiber integration technology, and is easy to implement.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. An optical fiber interference filter based on a multi-core optical fiber, characterized in that: It is composed of a beam splitter, a beam combiner and multiple sections of multi-core optical fibers; the beam splitter and the beam combiner pigtails are both single-mode optical fibers, and one end of each section of the multi-core optical fibers is connected to the pigtail of the beam splitter, and the other end is connected to the pigtail of the beam combiner; The multi-core optical fiber supports the transmission of two modes of light. When light enters the multi-core optical fiber from the pigtail of the beam splitter, two modes of light are excited. The two modes of light pass through the multi-core optical fiber and are coupled to the pigtail of the beam combiner. When the two modes of light are transmitted in the multi-core optical fiber, they experience different optical paths, and they interfere with each other in the pigtail of the combiner. The interference enhancement wavelength and free spectrum range in the interference curve are related to the length of the multi-core optical fiber. Multiple sections of multi-core optical fiber, interference enhancement at the designed wavelength; The lengths of the multiple sections of multi-core optical fibers are different, and the optical paths of the two mode lights in different multi-core optical fibers are different, so that the free spectral ranges of the interference curves after passing through different multi-core optical fibers are different. The spectra passing through each section of the multi-core optical fiber are superimposed to obtain the required transmission spectrum.

2. The optical fiber interference filter based on multi-core optical fiber according to claim 1, characterized in that: The beam splitter is used to split the light transmitted in the optical fiber into multiple beams; The beam combiner is used to couple the separated multiple beams of light to the same optical fiber, that is, the pigtail of the beam combiner.

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