Transmission and reflection high-isolation wavelength division multiplexer

Abstract

The utility model relates to an optical fiber technology, in particular to a transmission and reflection high-isolation wavelength division multiplexer, which comprises a double-optical-fiber collimator and a single-optical-fiber collimator which are integrated into a whole through a large glass tube. A large filter plate group and a small filter plate are further integrated on the large glass tube, the small filter plate is arranged at one end of the double-fiber collimator, the large filter plate group is arranged at one end close to the single-fiber collimator, the large filter plate group and the small filter plate are oppositely arranged, and the transmission wavelength of the large filter plate group is the reflection wavelength of the small filter plate. According to the utility model, the high-specification isolation requirement of two channels can be met by using one device, the film coating requirement on the filter plate is extremely low, and only three optical fibers are provided, so that the defects of occupied space and too many messy optical fibers during use are greatly reduced, the film coating difficulty is reduced, and the cost is greatly saved at the same time.

Description

Technical Field

[0001] The utility model relates to an optical fiber technology, in particular to a transmission and reflection high-isolation wavelength division multiplexer. Background Art

[0002] The emergence of WDM (Wavelength Division Multiplexing) technology has completely changed the way people communicate. Its huge bandwidth, excellent high speed and transparency make it the preferred technology in today's fiber optic communication application field.

[0003] As fiber-optic communication develops rapidly, with the increase in transmission capacity requirements (such as transmitting video images, etc.), it is directly required to maximize the use of fiber width. Wavelength division multiplexing (WDM) technology is to multiplex the optical modulated signals of different wavelengths into one optical fiber for transmission according to the wavelength, and can also decompose the multi-wavelength optical modulated signals transmitted simultaneously in the same optical fiber into individual wavelengths for separate output. It is one of the most effective solutions to increase the capacity of optical fiber communication, and therefore has been widely used in current optical communication networks.

[0004] However, as the application of optical fiber communication becomes more and more extensive and the technology becomes more and more mature, the requirements for various indicators of wavelength division multiplexing devices are becoming higher and higher, and the standards are becoming more and more stringent. Among them, regarding the isolation indicator, there are multiple wavelengths transmitted in an optical fiber, and a sufficiently high isolation degree is required between them, otherwise the signals will interfere with each other, so a high isolation degree is required to filter out the redundant wavelengths as much as possible and only retain the required wavelengths. Utility Model Content

[0005] The purpose of the utility model is to provide a wavelength division multiplexer with high isolation between transmission and reflection to solve the problems raised in the above background technology.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] A transmission and reflection high isolation wavelength division multiplexer, comprising a dual-fiber collimator and a single-fiber collimator, wherein the single-fiber collimator and the dual-fiber collimator are integrated into one body through a large glass tube;

[0008] The large glass tube is also integrated with a large filter group and a small filter. The small filter is arranged at one end of the dual-fiber collimator, and the large filter group is arranged at an end close to the single-fiber collimator. The large filter group and the small filter are arranged oppositely, and the transmission wavelength of the large filter group is the reflection wavelength of the small filter.

[0009] The transmission and reflection high isolation wavelength division multiplexer as described above: one end of the dual-fiber collimator is respectively provided with a common end fiber and a reflection end fiber; one end of the single-fiber collimator is provided with a transmission end fiber;

[0010] There is a gap between the common end optical fiber and the reflection end optical fiber.

[0011] The transmission and reflection high isolation wavelength division multiplexer as described above: the dual-fiber collimator includes a dual-fiber pigtail, the dual-fiber pigtail is fixed in a first small glass tube, the common end optical fiber and the reflection end optical fiber pass through one end of the first small glass tube, and a small filter is attached to one of the core holes of the dual-fiber pigtail.

[0012] The transmission and reflection high isolation wavelength division multiplexer as described above: the dual-fiber collimator also includes a self-focusing lens, and the small filter is located between the self-focusing lens and the dual-fiber pigtail;

[0013] The large filter group is arranged at an end of the self-focusing lens away from the small filter.

[0014] The transmission and reflection high isolation wavelength division multiplexer as described above: the single fiber collimator comprises a second small glass tube, a single fiber pigtail, and a spherical lens, wherein the single fiber pigtail and the spherical lens are both arranged in the second small glass tube;

[0015] The first small glass tube and the second small glass tube are both made of high borosilicate glass, and the first small glass tube is located at the end of the dual-fiber collimator.

[0016] The transmission and reflection high isolation wavelength division multiplexer as described above: the transmission end optical fiber is inserted into the single-hole capillary in the single-fiber pigtail and fixed by glue, one end of which is the pigtail and the other end is an 8° surface and coated with an anti-reflection film; one end of the spherical lens is a spherical surface and the other end is an 8° inclined surface, and its 8° inclined surface corresponds to the 8° end of the transmission end optical fiber;

[0017] The common end optical fiber and the reflection end optical fiber pass through the double-hole capillary in the dual-fiber pigtail and are bonded and fixed. One end is the pigtail and the other end is also an 8° surface. One end of the self-focusing lens is an 8° surface and the other end is a 0° surface.

[0018] Compared with the prior art, the beneficial effects of the utility model are as follows: by respectively arranging a large filter group and a small filter between a single-fiber collimator and a dual-fiber collimator, and after the two are arranged in reverse, the transmission wavelength and the reflection wavelength between the two correspond to each other; by using the double combination to improve the isolation between the reflected light beam and the transmitted light beam, the use volume of the overall structure is greatly reduced, and the problems of excessive volume and too many and cluttered optical fibers are avoided.

[0019] One device can meet the high-specification isolation requirements of two channels, and the coating requirements for the filter are extremely low. There are only three optical fibers, which greatly reduces the space occupied during use. The defect of too many and cluttered optical fibers reduces the difficulty of coating and greatly saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the internal design structure of the transmission and reflection high isolation wavelength division multiplexer.

[0021] Figure 2 It is a schematic diagram of the structure of the dual-fiber collimator in the transmission and reflection high isolation wavelength division multiplexer.

[0022] Figure 3 It is a top view of the cooperation between the dual-fiber pigtail and the small filter 13 in the transmission and reflection high isolation wavelength division multiplexer.

[0023] Figure 4 Schematic diagram of the structure of a single fiber collimator in a wavelength division multiplexer with high isolation between transmission and reflection.

[0024] Figure 5 This is a diagram of the optical path in a transmission and reflection high-isolation wavelength division multiplexer.

[0025] Figure 6 This is a scan spectrum of an existing product.

[0026] Figure 7 This is a scanning spectrum diagram of the product sample in the utility model.

[0027] In the figure: 1-dual fiber collimator; 11-first small glass tube; 12-dual fiber pigtail; 13-small filter; 14-self-focusing lens; 15-large filter group;

[0028] 2-single fiber collimator; 21-second small glass tube; 22-single fiber pigtail; 23-spherical lens;

[0029] 3-Large glass tube;

[0030] 4- Public end optical fiber;

[0031] 5-reflection end optical fiber;

[0032] 6- Transmission end optical fiber. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0034] See also Figure 1 to Figure 7As an embodiment of the utility model, the transmission and reflection high isolation wavelength division multiplexer includes a dual-fiber collimator 1 and a single-fiber collimator 2, wherein the single-fiber collimator 2 and the dual-fiber collimator 1 are integrated into one body through a large glass tube 3 to form a transmission and reflection wavelength division multiplexer;

[0035] The large glass tube 3 is also integrated with a large filter group 15 and a small filter 13. The small filter 13 is arranged at one end of the dual-fiber collimator 1, and the large filter group 15 is arranged at an end close to the single-fiber collimator 2. The large filter group 15 and the small filter 13 are arranged oppositely, that is, the transmission wavelength of the large filter group 15 is the reflection wavelength of the small filter 13.

[0036] In this embodiment, a large filter group 15 and a small filter 13 are respectively arranged between the single-fiber collimator 2 and the dual-fiber collimator 1, and the two are arranged inversely, so that the transmission wavelength and the reflection wavelength between the two correspond to each other; the isolation between the reflected light beam and the transmitted light beam is improved by means of the double combination, which greatly reduces the use volume of the overall structure and avoids the problems of excessive volume and too many and cluttered optical fibers.

[0037] In the utility model, one device is used to meet the high-specification isolation requirements of two channels, and the coating requirements for the filter are extremely low. There are only three optical fibers, which greatly reduces the space occupied during use and eliminates the defects of too many and cluttered optical fibers, reduces the difficulty of coating and greatly saves costs.

[0038] As a further solution of the utility model, one end of the dual-fiber collimator 1 is respectively provided with a common end optical fiber 4 and a reflection end optical fiber 5; one end of the single-fiber collimator 2 is provided with a transmission end optical fiber 6;

[0039] There is a gap between the common end optical fiber 4 and the reflection end optical fiber 5, which can avoid the problems of light leakage and large loss to a certain extent;

[0040] In a specific application process, the gap distance between the common end optical fiber 4 and the reflection end optical fiber 5 should be greater than 160 um.

[0041] As a further solution of the utility model, the dual-fiber collimator 1 includes a dual-fiber pigtail 12, which is fixed in a first small glass tube 11, and the common end optical fiber 4 and the reflection end optical fiber 5 pass through one end of the first small glass tube 11, and a small filter 13 is attached to one of the core holes of the dual-fiber pigtail 12.

[0042] As a further solution of the utility model, the dual-fiber collimator 1 further includes a self-focusing lens 14, and the small filter 13 is located between the self-focusing lens 14 and the dual-fiber pigtail 12;

[0043] The large filter group 15 is arranged at an end of the self-focusing lens 14 away from the small filter 13 .

[0044] In this embodiment, the common end optical fiber 4 of the dual-fiber collimator 1 inputs the light beams λ1 and λ2 , and the incident light beams pass through the self-focusing lens 14 and enter the large filter group 15 .

[0045] As a further solution of the utility model, the large filter group 15 is a two-piece structure, and the two pieces are bonded in the same direction; one side of the large filter is a reflective film, and the other side is an anti-reflection film, and the film system specifications are T-λ1 / R-λ2, T / R-ISO>30 / 15dB.

[0046] Wherein, both the large filter and the small filter 13 are coated, and the coating processes are opposite, so as to achieve the effect that the transmission wavelength corresponds to the reflection wavelength.

[0047] Transmission end: Figure 2 As shown, the common end optical fiber 4 in the dual-fiber collimator 1 inputs light beams λ1 and λ2, and the incident light beams reach the self-focusing lens 14. When passing through the large filter group 15, the input light beams λ1 and λ2 first pass through the first piece of the large filter group 15, whose film system specifications are T-λ1 / R-λ2, T / R-ISO>30 / 15dB, and the input light beams are divided into two beams, namely, the transmitted light beam λ1 and the reflected light beam λ2; when the transmitted light beam λ1 continues to pass through the second piece of the large filter group 15, its film system specifications are T-λ1 / R-λ2, T / R-ISO>30 / 15dB, and the transmitted light beam λ1 still contains a very small amount of reflected light beam λ2. After another splitting, the reflected light beam λ2 in the transmitted light beam λ1 can be ignored at this time, and is output from the transmission end optical fiber 6 of the single-fiber collimator 2. At this time, the transmitted light beam λ1 is superimposed with the transmission isolation after two transmissions, reaching 30+30=60dB or more, thereby ensuring the high isolation of the transmission.

[0048] Reflector: Figure 2 As shown, the common end optical fiber 4 of the dual-fiber collimator 1 inputs the input light beams λ1 and λ2, the incident light beam reaches the self-focusing lens 14, and the reflected light beam λ2 is reflected back by the first piece of the large filter group 15, whose film system specification is T-λ1 / R-λ2, T / R-ISO>30 / 15dB, and passes through the small filter 13. At this time, the reflected light beam λ2 still contains a very small amount of the transmitted light beam λ1. Because the film system specification of the small filter 13 is T-λ2 / R-λ1, T / R-ISO>30 / 15dB, the reflected light beam λ2 undergoes a transmission process at this time, and then completes the reflection through the reflective end optical fiber 5 of the dual-fiber collimator 1. At this time, after the reflected light beam λ2 is reflected by the large filter once and transmitted by the small filter 13 once, the reflection isolation is improved by superposition, reaching 30+15=45dB or more, ensuring the high reflection isolation.

[0049] As a further solution of the utility model, the single fiber collimator 2 includes a second small glass tube 21, a single fiber pigtail 22, and a spherical lens 23, wherein the single fiber pigtail 22 and the spherical lens 23 are both arranged in the second small glass tube 21;

[0050] The first small glass tube 11 and the second small glass tube 21 are both made of high borosilicate glass. The first small glass tube 11 is located at the end of the dual-fiber collimator 1 and plays the role of a waist drum to ensure that it fits the inner diameter of the outermost large glass tube 3 to facilitate glue bonding.

[0051] Correspondingly, the second small glass tube 21 is used as a connecting bridge to fix the single fiber pigtail 22 and the spherical lens 23 together.

[0052] The transmission end optical fiber 6 is inserted into the single-hole capillary in the single-fiber pigtail 22 and fixed by glue. One end is the pigtail and the other end is ground to 8° and coated with an anti-reflection film.

[0053] One end of the spherical lens 23 is a spherical surface, and the other end is an 8° inclined surface, and the 8° inclined surface corresponds to the 8° end of the transmission end optical fiber 6; both ends of the spherical lens 23 are coated with anti-reflection films.

[0054] In addition, the common end optical fiber 4 and the reflection end optical fiber 5 are inserted into the double-hole capillary in the dual-fiber pigtail 12, and then fixed with glue. One end is the pigtail, and the other end is also ground into 8° and coated with an anti-reflection film.

[0055] The small filter 13 is a rectangular crystal, made of a glass substrate and dozens of layers of dielectric films of different materials, different refractive indices and different thicknesses, with a reflective film on one side and an anti-reflective film on the other side. The film system specifications are T-λ2 / R-λ1, T / R-ISO>30 / 15dB.

[0056] One end of the self-focusing lens 14 is 8°, and the other end is 0°, and both ends are coated with anti-reflection films.

[0057] See below Figure 5 , internal light path diagram, where > represents the wavelength of λ1, ) represents the wavelength of λ2, and the number represents the intensity of the light. The fewer the number, the weaker the light, which means the higher the isolation.

[0058] For comparison, the scanning spectra of products currently on the market are as follows: Figure 6 , and the sample scanning spectrum in the utility model is as follows Figure 7 .

[0059] The utility model provides a high isolation wavelength division multiplexer with high isolation, simple structure, low price, and is conducive to popularization. The utility model relates to a high isolation wavelength division multiplexer with exquisite structure, great economic value and use value, simple process structure, small size, and convenient production.

[0060] Moreover, in the utility model, the isolation of the reflected light beam and the transmitted light beam is improved through double combination, the isolation of the reflected light beam is increased to more than 45dB, and the isolation of the transmitted light beam is more than 60dB, which greatly reduces the usage volume, avoids the defects of too large volume and too many messy optical fibers, reduces the difficulty of coating and greatly saves costs.

[0061] The above embodiments are exemplary rather than restrictive, so without departing from the spirit or basic features of the present invention, the technical solutions of the present invention that can be implemented in other specific forms are all included in the present invention.

Claims

1. A transmission and reflection high isolation wavelength division multiplexer, comprising a dual fiber collimator (1) and a single fiber collimator (2) integrated by a large glass tube (3), characterized in that: The large glass tube (3) is further integrated with a large filter group (15) and a small filter (13); the small filter (13) is arranged at one end of the dual-fiber collimator (1); the large filter group (15) is arranged at an end close to the single-fiber collimator (2); the large filter group (15) and the small filter (13) are arranged opposite to each other; the transmission wavelength of the large filter group (15) is the reflection wavelength of the small filter (13).

2. The transmission and reflection high isolation wavelength division multiplexer according to claim 1, characterized in that: One end of the dual-fiber collimator (1) is provided with a common end optical fiber (4) and a reflection end optical fiber (5); one end of the single-fiber collimator (2) is provided with a transmission end optical fiber (6); There is a gap between the common end optical fiber (4) and the reflection end optical fiber (5).

3. The transmission and reflection high isolation wavelength division multiplexer according to claim 2, characterized in that: The dual-fiber collimator (1) comprises a dual-fiber pigtail (12), wherein the dual-fiber pigtail (12) is fixed in a first small glass tube (11), a common end optical fiber (4) and a reflection end optical fiber (5) pass through one end of the first small glass tube (11), and a small filter (13) is attached to one of the core holes of the dual-fiber pigtail (12).

4. The transmission and reflection high isolation wavelength division multiplexer according to claim 3, characterized in that: The dual-fiber collimator (1) further comprises a self-focusing lens (14), and the small filter (13) is located between the self-focusing lens (14) and the dual-fiber pigtail (12); The large filter group (15) is arranged at an end of the self-focusing lens (14) away from the small filter (13).

5. The transmission and reflection high isolation wavelength division multiplexer according to claim 4, characterized in that: The single-fiber collimator (2) comprises a second small glass tube (21), a single-fiber pigtail (22), and a spherical lens (23), wherein the single-fiber pigtail (22) and the spherical lens (23) are both arranged in the second small glass tube (21); The first small glass tube (11) and the second small glass tube (21) are both made of high borosilicate glass, and the first small glass tube (11) is located at the end of the dual-fiber collimator (1).

6. The transmission and reflection high isolation wavelength division multiplexer according to claim 5, characterized in that: The transmission end optical fiber (6) is inserted into a single-hole capillary in a single-fiber pigtail (22) and fixed by glue, one end of which is a pigtail and the other end is an 8° surface and coated with an anti-reflection film; one end of the spherical lens (23) is a spherical surface and the other end is an 8° inclined surface, and the 8° inclined surface corresponds to the 8° end of the transmission end optical fiber (6); The common end optical fiber (4) and the reflection end optical fiber (5) are inserted into the double-hole capillary in the dual-fiber pigtail (12) and are bonded and fixed. One end is the pigtail and the other end is also an 8° surface. One end of the self-focusing lens (14) is an 8° surface and the other end is a 0° surface.

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