A single fiber bidirectional optical device

Abstract

This invention discloses a single-fiber bidirectional optical device, comprising: a circular-square tube body having a first port, a second port, and a third port; an optical transmitter disposed at the first port; an optical receiver disposed at the second port; an optical fiber adapter disposed at the third port; and an optical assembly disposed within the inner cavity of the circular-square tube body, including a first filter; the first filter being located between the optical transmitter and the optical fiber adapter; a diffuser groove being formed on the inner wall of the circular-square tube body, the inner wall of the diffuser groove being an arc surface; this invention, by setting a diffuser groove to disperse and absorb part of the emitted light reflected back from the first filter, prevents this part of the emitted light from returning to the first filter along the same path, thereby reducing optical crosstalk to the optical receiver and preventing this part of the emitted light from being concentrated and reflected back to the optical transmitter, thus reducing interference to the optical transmitter.

Description

Technical Field

[0001] This invention belongs to the field of optical fiber communication technology, specifically a single-fiber bidirectional optical device. Background Technology

[0002] Currently, single-fiber bidirectional wavelength division multiplexing (WDM) communication technology has been widely used in the field of optical communication. As the data rate increases, the optical power of optical devices also increases, and the requirements for optical crosstalk performance also increase accordingly, especially for single-fiber bidirectional devices with the same wavelength.

[0003] For single-fiber bidirectional devices, light that does not completely pass through the 45° filter will be reflected and partially enter the optical receiver, interfering with normal signal transmission. Specifically, after the emitted light is reflected by the 45° filter, part of the light hits the corresponding horizontal plane of the round-square tube and then returns vertically along the original path, passing through the 45° filter and entering the optical receiver, causing crosstalk.

[0004] The relevant documents disclose a 50G Combo-PON optical device and its assembly method. The optical device includes a tube body on which multiple laser components and multiple detector components are mounted. Inside the tube body, there are filters, beam splitters, and lenses. The filters are used to transmit first light emitted by a first laser component to the beam splitter and to reflect second light emitted by a second laser component to the beam splitter. The beam splitter is used to transmit the first and second light to the lens. The lens is used to converge the first and second light and transmit it to the output of the optical port. The lens is used to convert light of multiple wavelengths emitted from the optical port into parallel light and transmit it to the beam splitter. The beam splitter is used to reflect the parallel light of each wavelength once or multiple times and then transmit it to the corresponding reflective surface. The reflective surface is used to reflect the parallel light to the corresponding detector component.

[0005] Such optical devices are prone to causing optical crosstalk to optical transmitters. Summary of the Invention

[0006] The purpose of this invention is to provide a single-fiber bidirectional optical device to solve at least one of the above-mentioned technical problems.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A single-fiber bidirectional optical device, comprising:

[0009] A round-square tube body, which is provided with a first pipe opening, a second pipe opening and a third pipe opening;

[0010] A light transmitter, located at the first port, is used to convert electrical signals into light signals and transmit them.

[0011] A light receiver, located at the second port, is used to receive light signals and convert them into electrical signals;

[0012] An optical fiber adapter, located at the third port, is used to connect an optical fiber. The transmitted light emitted by the optical transmitter can be coupled to the optical fiber through the optical fiber adapter, and the received light transmitted from the optical fiber can be coupled to the optical receiver through the optical fiber adapter, thereby realizing bidirectional communication on a single fiber.

[0013] An optical component, disposed within the inner cavity of the circular-square tube, includes a first filter. The optical component is used to adjust the optical path. Specifically, the optical component is used to couple the emitted light emitted by the optical transmitter to the fiber optic adapter, and also to couple the received light transmitted from the fiber optic adapter to the optical receiver. The first filter is used to transmit the emitted light emitted by the optical transmitter, couple the emitted light to the fiber optic adapter, and also to reflect the received light transmitted from the fiber optic adapter, couple the received light to the optical receiver.

[0014] The first filter is located between the optical transmitter and the optical fiber adapter, so that the emitted light emitted by the optical transmitter is transmitted to the optical fiber adapter, and the received light entering from the optical fiber adapter is reflected to the optical receiver;

[0015] The inner wall of the circular tube is provided with a diffuser groove, and the inner wall of the diffuser groove is an arc surface to disperse part of the emitted light reflected back by the first filter. By setting and opening the diffuser groove, the emitted light reflected back by the first filter is dispersed, which can prevent the emitted light reflected back by the first filter from being reflected back to the first filter again along the same path, and can also prevent the emitted light reflected back by the first filter from being concentrated and sent back to the light emitter, thereby reducing the impact on the light emitter.

[0016] Furthermore, the diffuser groove is an inverted conical groove, which facilitates processing;

[0017] When the emitted light from the optical transmitter hits the first filter, it is nearly parallel light, or more specifically, it is generally converging light with a convergence angle of about 8°. Part of the emitted light passes through the first filter and hits the fiber optic adapter, while another part is reflected into the inverted conical groove. Because the groove wall is curved, the emitted light is reflected and dispersed when it hits the groove, becoming stray light. This prevents the emitted light from being concentrated and reflected back to the first filter and then passing through the second filter to enter the optical transmitter, thus avoiding any impact on the optical transmitter.

[0018] Furthermore, the angle between the axis of the inverted conical groove and the generatrix is ​​greater than 0° and less than 30°, greater than 30° and less than 45°, and greater than 45° and less than 90°.

[0019] Furthermore, the angle between the axis of the inverted conical groove and the generatrix is ​​in the range of 22°-28°. When the emitted light enters the inverted conical groove, it can be reflected multiple times. Each time the emitted light is reflected, a portion of it is absorbed by the inverted conical groove. The more times it is reflected, the better the absorption effect of the inverted conical groove on the emitted light. Therefore, it can reduce the optical crosstalk of the emitted light to the optical transmitter and the optical receiver.

[0020] Furthermore, the fiber optic adapter includes a fiber optic ferrule, the end face of which is beveled.

[0021] Furthermore, the optical component also includes an isolator disposed between the light emitter and the first filter.

[0022] Furthermore, the optical component also includes a second filter, which is disposed between the light receiver and the first filter, and is used to filter out light of other wavelengths besides the received light.

[0023] Furthermore, a light-blocking ring is provided between the second filter and the optical receiver. The two ends of the light-blocking ring are respectively sealed to the receiving end of the optical receiver and the second filter. By setting the light-blocking ring, a channel for receiving light to pass through is formed between the second filter and the optical receiver, blocking other stray light from entering the optical receiver without passing through the second filter. That is, light can only pass through the second filter and enter the optical receiver.

[0024] Furthermore, the light-blocking ring, the second filter, and the receiving end of the optical receiver are coaxially arranged so that the received light can pass smoothly through the light-blocking ring and enter the optical receiver.

[0025] Furthermore, the walls of the diffuser groove are roughened to further enhance the diffuser groove's effect on scattering and absorbing emitted light.

[0026] Furthermore, the roughness of the groove wall of the diffuser is in the range of 50-150 mesh, which can achieve a better light dispersion effect.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] (1) The present invention uses a diffuser groove to disperse and absorb part of the emitted light reflected back by the first filter, so that this part of the emitted light cannot return to the first filter along the original path. This can reduce optical crosstalk to the optical receiver and also prevent this part of the emitted light from being concentrated and reflected to the optical transmitter, thus reducing interference to the optical transmitter.

[0029] (2) By setting up a light-blocking ring, the present invention forms a channel between the second filter and the optical receiver for the received light to pass through, blocking other stray light from entering the optical receiver without passing through the second filter. That is, light can only pass through the second filter and enter the optical receiver, which can reduce the optical crosstalk to the optical receiver. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a single-fiber bidirectional optical device structure in this embodiment;

[0031] Figure 2 This is the optical path of the emitted light in the inverted conical groove from a top-down perspective in this embodiment;

[0032] Figure 3 This is the optical path of the emitted light in the inverted conical groove from the frontal viewing angle in this embodiment;

[0033] In the diagram: 1. Round tube; 2. Optical transmitter; 3. Optical receiver; 4. Fiber optic adapter; 5. Optical components; 501. First filter; 502. Second filter; 503. Light blocking ring; 504. Isolator; 6. Diffusing groove. Detailed Implementation

[0034] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] like Figure 1 As shown, this embodiment provides a single-fiber bidirectional optical device, including a round-square tube 1, an optical transmitter 2, an optical receiver 3, an optical fiber adapter 4, and an optical component 5.

[0036] Specifically, the round-square tube 1 is provided with a first port, a second port and a third port, which are used to carry and fix the optical transmitter 2, the optical receiver 3, the fiber optic adapter 4 and the optical components 5.

[0037] Specifically, the optical transmitter 2 is located at the first port, the optical receiver 3 is located at the second port, the optical fiber adapter 4 is located at the third port, and the optical component 5 is located inside the round-square tube 1.

[0038] Typically, the first and second openings are respectively located on adjacent sidewalls of the round-square tube 1, the first and third openings are respectively located on the sidewalls along the length of the round-square tube 1, and the second opening is located on the sidewalls along the width of the round-square tube 1.

[0039] The round-square tube 1 is generally made of metal to achieve electromagnetic shielding and heat dissipation. Specifically, the light emitter 2 makes thermal contact with the round-square tube 1 through the first opening.

[0040] In this embodiment, the optical transmitter 2 is fixed to the first port by laser welding, the optical receiver 3 is sealed and fixed to the second port by epoxy resin adhesive, and the optical fiber adapter 4 is fixed to the third port by laser welding.

[0041] The optical transmitter 2 contains an optical emitting chip for transmitting optical signals. Specifically, the optical transmitter 2 includes a socket and a cap, with the cap covering the socket, forming a cavity with the socket. The optical emitting chip and a first lens are mounted on the socket. The optical signal emitted by the optical emitting chip is focused by the first lens and then enters the optical assembly 5, where it is further focused and coupled to the fiber optic adapter 4.

[0042] The optical receiver 3 contains an optical receiving chip for receiving optical signals. Specifically, the optical receiver 3 includes a socket and a cap, with the cap covering the socket, forming a cavity with the socket. The optical receiving chip and a second lens are mounted on the socket. The optical signal emitted by the fiber optic adapter 4 is reflected by the optical component 5 to the second lens inside the optical receiver 3, and then focused onto the optical receiving chip by the second lens.

[0043] Optical component 5, disposed in the inner cavity of the round-square tube 1, includes a first filter 501, a second filter 502, a light-blocking ring 503 and an isolator 504, used to adjust the light signal emitted by the light transmitter 2 and the light signal incident on the light receiver 3.

[0044] The first filter 501 is located between the optical transmitter 2 and the fiber optic adapter 4, and directly below the optical receiver 3, so that the emitted light emitted by the optical transmitter 2 is transmitted to the fiber optic adapter 4, and the received light entering from the fiber optic adapter 4 is reflected to the optical receiver 3.

[0045] The first filter 501 is a 45° filter, which means that the angle between the incident light and the filter normal is 45°.

[0046] The second filter 502 is disposed between the optical receiver 3 and the first filter 501, and is used to filter out light of other wavelengths besides the received light.

[0047] The second filter 502 is a 0° filter, which means that the angle between the incident light and the filter normal is 0°. That is, the incident light enters the 0° filter perpendicularly.

[0048] The emitted light from the optical transmitter 2 passes directly through the first filter 501 to the optical fiber adapter 4. When the received light emitted from the optical fiber adapter 4 hits the first filter 501, it is reflected onto the second filter 502, passes through the second filter 502, and then enters the optical receiver 3.

[0049] A light-blocking ring 503 is disposed between the second filter 502 and the light receiver 3. The two ends of the light-blocking ring 503 are respectively sealed to the receiving end of the light receiver 3 and the second filter 502 to prevent light from passing through the light-blocking ring 503 and entering the receiving end of the light receiver 3. The receiving end of the light receiver 3 refers to the end on which the second lens is disposed.

[0050] In this embodiment, the light-blocking ring 503 and the second filter 502 can be fixed by adhesive bonding, and the light-blocking ring 503 and the light receiver 3 can be fixed by adhesive bonding or welding.

[0051] In existing technology, a baffle can be set between the optical receiver 3 and the second filter 502, and the baffle is sealed and fixed to the inner wall of the second tube opening. A through hole is opened on the baffle, corresponding to the second filter 502. The baffle, the second optical port, and the optical receiver 3 together form a narrow sealed space, allowing only light to pass through the second filter 502 and enter the receiving end of the optical receiver 3. However, this setting method has two drawbacks. First, if the seal between the optical receiver 3 and the second tube opening is not tight, external light may enter the sealed space between the optical receiver 3 and the second tube opening, affecting the optical receiver 3 and causing optical crosstalk. Second, when sealing the optical receiver 3 and the second tube opening, epoxy resin is usually used. When the epoxy resin is heated and fixed, because the sealed space is relatively small, the gas expands when heated. Expansion of the epoxy resin adhesive can cause air bubbles to form, affecting the sealing effect between the light receiver 3 and the second port. During heating, the epoxy resin adhesive may also generate water vapor, which can disperse within the enclosed space and affect the light receiver 3. However, the solution adopted in this embodiment uses a light-blocking ring 503, which is directly and sealed to the light receiver 3. Even if the seal between the second port and the light receiver 3 is not tight, external light will have difficulty passing through the light-blocking ring 503 to reach the receiving end of the light receiver 3, thus reducing optical crosstalk. When the light receiver 3 is sealed and fixed to the second port, its connection point is also connected to the first and third ports. Therefore, when the second port and the light receiver 3 are fixed with epoxy resin adhesive, no air bubbles will be generated, and the generated water vapor can dissipate without affecting the light receiver 3.

[0052] Isolator 504, disposed between optical transmitter 2 and first filter 501, serves not only to prevent emitted light from optical transmitter 2 from returning to optical transmitter 2, but also to prevent received light from entering optical transmitter 2. Due to the presence of isolator 504, received light has difficulty entering optical transmitter 2, reducing optical crosstalk within optical transmitter 2.

[0053] Fiber optic adapter 4 is used to connect optical fibers. Specifically, optical transmitter 2 is located at the first port of the round-square tube 1, optical receiver 3 is located at the second port of the round-square tube 1, and fiber optic adapter 4 is located at the third port of the round-square tube 1. Optical transmitter 2 and optical receiver 3 establish optical connections with fiber optic adapter 4 respectively. The optical signal emitted by optical transmitter 2 and the light received by optical receiver 3 are both transmitted through the same optical fiber in fiber optic adapter 4. That is, the same optical fiber in fiber optic adapter 4 is the transmission channel for light entering and exiting the optical device, and the optical device realizes a single-fiber bidirectional optical transmission mode.

[0054] The fiber optic adapter 4 includes a housing and a fiber optic ferrule housed within the housing. The fiber optic ferrule can be formed by encasing an optical fiber in ceramic material. The optical fiber is used for light transmission, and ceramic has high processing precision, allowing for high-precision alignment. The fiber optic ferrule is formed by combining the optical fiber and ceramic, and the optical fiber is fixed by fixing the ceramic. The ceramic material restricts the fixing direction of the optical fiber within the ferrule. Generally, the ceramic is processed into a cylinder, with a straight through-hole in the center. The optical fiber is inserted into the through-hole to achieve fixation, so the optical fiber is fixed straight within the ceramic cylinder. Within the fiber optic ferrule, the axial direction of the optical fiber is parallel to the axial direction of the fiber optic ferrule.

[0055] Light enters the optical fiber through the air. When the light enters the end face of the optical fiber perpendicularly, no refraction occurs. This method makes it easy to control the angle relationship between the light output direction of the laser chip and the optical fiber ferrule. However, perpendicular incidence will cause the reflected light to return along the original optical path. The returned reflected light passes through the first filter 501 and the second filter 502 and enters the light blocking ring 503.

[0056] To prevent reflected light from returning along the original optical path, the optical path is designed so that the light is not perpendicular to the fiber end face. To achieve this, the fiber end face is ground into a bevel. Specifically, the fiber is encased in ceramic to form a fiber ferrule, and the end face of the fiber ferrule is ground into a bevel. The fiber end face in the fiber ferrule is then also beveled.

[0057] Specifically, the fiber optic ferrule is composed of a ceramic cylinder encasing the optical fiber. The axial direction of the fiber ferrule is the same as that of the optical fiber. The light-incident surface of the fiber ferrule is ground into an inclined surface, which is the same as the light-incident surface of the optical fiber. The optical fiber is composed of a core layer and a cladding layer with different refractive indices. The light undergoes total internal reflection at the interface between the core layer and the cladding layer, thus confining the light to propagate within the core layer.

[0058] The end face of the fiber optic ferrule is coated with an anti-reflection film.

[0059] Antireflection coatings are transparent dielectric films used to reduce reflection loss. Specifically, incident light passes through the antireflection coating to the end face of the optical fiber, reducing light reflection and light return along the original path, thereby effectively reducing light return loss.

[0060] Receive light:

[0061] The received light received by the fiber optic ferrule of the fiber optic adapter 4 is reflected by the first filter 501 and then perpendicularly enters the second filter 502, where it is coupled to the optical receiver 3. Although some of the received light is also transmitted through the first filter 501 to the optical transmitter 2, the isolator 504 is provided to block some of the received light that is directed to the optical transmitter 2, thereby reducing optical crosstalk.

[0062] Emitting light:

[0063] The emitted light from optical transmitter 2 is transmitted through the first filter 501 to the fiber optic adapter 4 and coupled to the fiber optic ferrule end face of the fiber optic adapter 4. Because some of the emitted light is reflected at the fiber ferrule end face and then perpendicularly enters the second filter 502 after being reflected by the first filter 501, the second filter 502, which filters out all wavelengths of light other than the received light, makes it difficult for the emitted light to enter the optical receiver 3. The presence of the light-blocking ring 503 further reduces crosstalk and improves the crosstalk performance.

[0064] The inner wall of the round-square tube 1 is provided with a light-diffusing groove 6. The inner wall of the light-diffusing groove 6 is an arc surface to disperse part of the emitted light reflected back by the first filter 501. In this embodiment, the inner wall of the light-diffusing groove 6 refers to all the wall surfaces inside the light-diffusing groove 6.

[0065] As a preferred embodiment, the diffuser groove 6 is an inverted conical groove.

[0066] like Figure 2 As shown, when the diffuser groove 6 is an inverted conical groove, when the point on which the light hits the inverted conical groove deviates around the axis of the inverted conical groove, the incident angle will change. The part of the emitted light reflected into the inverted conical groove is calibrated by the light emitter 2 and then reflected by the first filter 501. It enters the inverted conical groove at an angle close to vertically downward. Therefore, the inverted conical groove can disperse these nearly vertically downward reflected lights.

[0067] Furthermore, the angle between the axis of the inverted conical groove and the generatrix is ​​greater than 0° and less than 30°, greater than 30° and less than 45°, and greater than 45° and less than 90°. That is, the angle between the axis of the inverted conical groove and the generatrix is ​​between 0° and 90°, but 0°, 30°, 45° and 90° are excluded. When the angle between the axis of the inverted conical groove and the generatrix is ​​30°, the part of the emitted light that is vertically downward into the inverted conical groove will return along the same path. When the angle between the axis of the inverted conical groove and the generatrix is ​​45°, the part of the emitted light that is vertically downward into the inverted conical groove will undergo one reflection and then be vertically upward again towards the first filter 501. Therefore, the above two angles need to be excluded.

[0068] As a preferred embodiment, the angle between the axis of the inverted conical groove and the generatrix can be in the range of 22°-28°, such as... Figure 3 As shown, when the angle between the axis of the inverted conical groove and the generatrix is ​​25°, the light enters the inverted conical groove. The light can be reflected three times. Each time it is reflected, a portion of the light is absorbed by the inverted conical groove, which can effectively reduce the crosstalk between the emitted light and the light emitter 2 and the light receiver 3. In this embodiment, the angle between the axis of the inverted conical groove and the generatrix is ​​preferably 25°.

[0069] Furthermore, the light-blocking ring 503, the second filter 502, and the receiving end of the optical receiver 3 are coaxially arranged.

[0070] Furthermore, the wall of the diffuser 6 is roughened, with a roughness range of 50-150 mesh, preferably 100 mesh. By setting the wall of the diffuser 6 to be roughened, the dispersion and absorption effect on the optical fiber can be enhanced, thereby reducing optical crosstalk.

[0071] It should be noted that although the present invention has been disclosed above with specific embodiments, the above embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A single fiber bidirectional optical device, characterized by, include: A round-square tube body, which is provided with a first pipe opening, a second pipe opening and a third pipe opening; A light emitter is located at the first port; A light receiver is located at the second port. The fiber optic adapter is located at the third port. An optical component, disposed within the inner cavity of the circular-square tube, includes a first filter. The first filter is located between the optical transmitter and the optical fiber adapter, so that the emitted light emitted by the optical transmitter is transmitted to the optical fiber adapter, and the received light entering from the optical fiber adapter is reflected to the optical receiver; The inner wall of the round-square tube is provided with a light-diffusing groove, and the inner wall of the light-diffusing groove is an arc surface to disperse part of the emitted light reflected back by the first filter.

2. The single fiber bidirectional optical device of claim 1, wherein, The diffuser groove is an inverted conical groove, and the angle between the axis of the inverted conical groove and the generatrix is ​​greater than 0° and less than 30°, greater than 30° and less than 45°, and greater than 45° and less than 90°.

3. The single-fiber bidirectional optical device according to claim 2, characterized in that, The angle between the axis of the inverted conical groove and the generatrix ranges from 22° to 28°.

4. The single-fiber bidirectional optical device according to claim 1, characterized in that, The fiber optic adapter includes a fiber optic ferrule, the end face of which is beveled.

5. The single-fiber bidirectional optical device according to claim 1, characterized in that, The optical component also includes an isolator disposed between the light emitter and the first filter.

6. The single-fiber bidirectional optical device according to claim 1, characterized in that, The optical component further includes a second filter, which is disposed between the light receiver and the first filter to filter out light of other wavelengths besides the received light.

7. The single-fiber bidirectional optical device according to claim 6, characterized in that, A light-blocking ring is provided between the second filter and the optical receiver, and the two ends of the light-blocking ring are respectively sealed to the receiving end of the optical receiver and the second filter.

8. The single-fiber bidirectional optical device according to claim 7, characterized in that, The light-blocking ring, the second filter, and the receiving end of the optical receiver are coaxially arranged.

9. The single-fiber bidirectional optical device according to claim 1, characterized in that, The walls of the diffuser groove are rough.

10. The single-fiber bidirectional optical device according to claim 9, characterized in that, The roughness of the groove wall of the diffuser is in the range of 50-150 mesh.

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