KR0165495B1 - Wavelength division multiplexer for otpcial telecommunication - Google Patents

Abstract

A photosynthesis splitter that can be used for optical communication is disclosed. A photosynthesis splitter is a device required to simultaneously transmit or receive two optical signals of different wavelengths through a single optical fiber.

The photosynthetic spectrometer, which requires precision, has a complicated structure because it uses a plurality of lenses, and assembly is not easy with respect to alignment of the optical axis.

Such structural complexity and assembly and alignment problems can be greatly improved and efficiency can be improved by reducing the number of lenses, the number of parts, and attaching a filter to the lens holder.

Such an optical splitter may be used for transmission or reception equipment for optical communication.

Description

Optical splitter structure for optical communication

1 is a cross-sectional view of a conventional dual wavelength coupler.

2 is a diagram showing an optical signal propagation path in the case of bidirectional communication in the dual wavelength coupler of FIG.

3 is a cross-sectional view showing the structure of another conventional photosynthetic splitter.

Figure 4 is a cross-sectional view showing the structure of the photosynthesis splitter according to the present invention.

5 is a schematic diagram showing a path of an optical signal in the photosynthesizer of FIG.

And,

6 is a schematic diagram showing the path of an optical signal in another embodiment of the photosynthetic splitter of the present invention.

* Explanation of symbols for main parts of the drawings

1: first optical fiber 2: second optical fiber

3: first ferrule 4-1: first lens holder

4-2: second lens holder 5: filter

6-1,6-2: ball lens 7: body

8: second ferrule 9: third optical fiber 9

10: gradient index lens 12,32: filter

14,16 spherical lens 22 body

26: optical fiber 30: dichroic filter

38: PIN diode 42: light emitting element

1a, 2a, 3a: optical fiber 4a, 41a, 5a, 51a: lens assembly

7a: filter 8a, 9a: optical fiber support

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an optical splitter used for optical communication, and more particularly, to a structure of an optical splitter used for communicating optical signals having two different wavelengths through a single optical fiber.

As in the case of other communications, in optical communications, it becomes a very important problem how much information can be communicated at the same time using a certain facility. In other words, it is a matter of how much time can communicate the same amount of information with a relatively small amount of equipment. This problem becomes more important when long distance communication requires a large amount of information to be communicated using a limited communication line.

In this respect, two optical signals having two different wavelengths which do not interfere with each other are used to simultaneously communicate using a single optical fiber. This method of communication not only enables communication by a small number of communication devices, but also allows the number of communication lines to be halved.

Structures for dual wavelength couplers used in such optical communications are disclosed in US Pat. No. 4,904,043. Dual wavelength coupler is another name for the photosynthetic splitter of the present invention. Here, a device is described which enables bidirectional communication (transmitter and receiver) and one-way communication (two transmitters or two receivers) over a single optical fiber. 1 is a side cross-sectional view of a conventional dual wavelength coupler. The main optics components are three lenses 10, 14, 16, that is, a gradient index (GRIN) lens 10, two spherical lenses 14, 16 and a dichroic. ) The filter 30 is used. The filter 30 has a characteristic of passing an optical signal of a specific wavelength and reflecting an optical signal of another wavelength. As shown, in relation to the input and output, a PIN (positive e-intrinsicnegative) diode 38, which is an optical sensing means for receiving an input signal, a light emitting element that is a light source for generating an optical signal of a predetermined wavelength, for example For example, the LED 42, the optical fiber 26 that transmits the optical signal, and the like form the basic basis of the wavelength coupler, and three lenses and filters of the spherical lens 14 and 16 and the gradient index (GRIN) lens 10. (12) (32) and a body (22) for receiving and supporting them.

The above structure description is for a case where bidirectional communication, i.e., transmission and reception, leads to different wavelengths. For example, the transmission signal is made of a wavelength of λ ₁ and the reception is made of a wavelength of λ ₂ . This is the case. The outgoing signal is generated in the light emitting element 42 and the received signal is sensed in the PIN diode 38.

FIG. 2 relates to the dual wavelength coupler of FIG. 1 and shows an optical signal propagation path when reception and transmission are simultaneously performed through a single optical fiber in bidirectional communication. The optical signal having the wavelength of λ ₂ received is parallel light through the gradient index lens, passes through a filter, is focused by the spherical lens 14, and is received by the PIN diode 38, which is a light sensing element. On the other hand, the light emitting element generates an optical signal having a wavelength of λ ₁ , which is passed through the spherical lens 16 and becomes parallel light, and is reflected by the filter 12 to be reflected by the gradient index lens 10. _An optical signal having a wavelength of ₂ is transmitted to the same optical fiber as the incoming optical fiber. This allows optical signals of two different wavelengths to be received and transmitted over a single optical fiber. In the one-way communication, the dual wavelength coupler receives two signals simultaneously using only two light sensing elements or only two light emitting elements, instead of using one light sensing element and one light emitting element. It can also be used as a receiver or a transmitter for transmitting or receiving.

However, optical devices, especially small devices, are required to have very high precision, and the influence of the error is relatively high, and thus the precision of machining is inevitably increased. In addition, as the number of parts increases, the amount of error is likely to increase cumulatively. Therefore, it can be predicted that the dual wavelength coupler of the above-described patent suffers from difficulties in actual manufacture and a price increase. In addition, processing errors in the components used are also likely to increase the price. For example, in the case of a very small spherical lens having a diameter of about 2mm-3mm, processing is relatively difficult, and handling difficulties in a process such as assembly can be easily predicted.

Another conventional device is shown in FIG. As shown, three optical fibers 1a, 2a and 3a are used for input and output, and a support body 8a made of glass for supporting the optical fibers 1a and 2a and a glass for supporting the optical fiber 3a. And a support body 9a, lens assemblies 4a and 41a and lens assemblies 5a and 51a, and a filter 7a.

In such a configuration, light including optical signals of two different wavelengths λ ₁ and λ ₂ is incident on the filter 7a via the lens assemblies 4a and 41a. Light having an optical signal of wavelength λ ₁ is reflected by the filter 7a and again passes through the lens assembly 4a (41a), and then is focused on the optical fiber 2a, and light having an optical signal of the wavelength λ ₂ is filtered. After passing through 7a and passing through the lens assemblies 5a and 51a, the light is collected and focused on the optical fiber 3a.

The problem with the device is that the optical fiber and the lens are integrated, so that the adjustment of the focal length, optical axis, etc. must be made by the filter, which makes the structure complicated. In addition, since the number of lenses is large, there are problems of error and increase in manufacturing cost.

Accordingly, an object of the present invention is to provide a photosynthesis splitter having a simple structure and easy fabrication.

The optical combiner used in the optical communication of the present invention has a body having a hollow portion for accommodating the components, each of which is an optical path having a wavelength of λ _{1 and} an optical signal having a wavelength of λ ₂ . A first optical fiber and a second optical fiber connected to an optical signal generating means having a light emitting element, a third optical fiber in which an optical signal having a wavelength of λ _{1 and} an optical signal having a wavelength of λ ₂ are embedded, and the first optical fiber and the second optical fiber are embedded The first ferrule (ferrule) having a part inserted into the body, the third optical fiber is embedded, and the second ferrule has a part inserted into the body, two lenses for focusing light having an optical signal A filter having a characteristic of reflecting light having an optical signal of a predetermined wavelength and transmitting light having an optical signal of another wavelength, a first lens holder provided with one of the lenses, and a lens provided with the lens; It comprises a two lens holder.

The structure of another optical splitter used for the optical communication of the present invention is a body having a hollow portion for accommodating components, each of which is a moving path of the optical signal and which detects the optical signal of the first wavelength and the optical signal of the second wavelength. A first optical fiber and a second optical fiber connected to an optical signal detecting means having an optical sensing element, a third optical fiber into which the optical signal of the first wavelength and the optical signal of the second wavelength are received, and the first optical fiber and the second optical fiber are embedded; A first ferrule in which a part thereof is inserted into the body, a second ferrule in which the third optical fiber is embedded, and a part of the third optical fiber is embedded in the body, two lenses for connecting light having an optical signal, and A filter having a characteristic of reflecting light having an optical signal of one wavelength and transmitting light having an optical signal of a second wavelength, a first lens holder provided with one of the lenses, and a second lens holder provided with a lens To It is configured to include.

With the above configuration, the structure of the photosynthesis splitter is simplified and the filter is fixed to the lens holder so that only the ferrule is finally adjusted, so that the adjustment is also easy.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 shows a cross-sectional view showing the structure of a device according to the invention. The first lens holder 4-1 and the second lens holder 4-2 are disposed adjacent to each other at the center of the hollow portion of the body 7, and the lens 6-6 is provided at the first lens holder 4-1. 1) and a filter 5 are provided, and only the lens 6-2 is provided in the second lens holder 4-2. The filter 5 has a characteristic of reflecting light having an optical signal of wavelength λ ₁ and transmitting light having an optical signal of λ ₂ of wavelength. Each of the first ferrule 3 and the second ferrule 8 is inserted into a portion of the body 7 so that a part thereof is inserted into the first ferrule 3 and the second ferrule 8, respectively. ). Further, the first optical fiber 1 and the second optical fiber 2 are embedded in the first ferrule 3, and the third optical fiber 9 is embedded in the second ferrule 8. The optical fibers 1, 2, 9 embedded in each ferrule 3, 8 are embedded such that their ends are located at a focal length of the lens away from the ends of the ferrules 3, 8 in contact with the lens holder. . Therefore, when assembly is completed, it is set to focus automatically.

In the above description, the filter 5 is attached to the first lens holder 4-1, but the filter 5 may be attached to the second lens holder 4-2. In addition, the lenses 6-1 and 6-2 may use a spherical lens, a gradient index lens, or a drum lens.

The operation of the photosynthetic splitter of the present invention will be described in detail with reference to FIG. Light having an optical signal having a wavelength λ ₁ emitted from the first optical fiber 1 is dispersed in the cross section of the first optical fiber 1, passes through the lens 6-1, is reflected by the filter 5, and the lens 6-6. The light is collected while passing through 1) and enters the second optical fiber 2. On the other hand, light having an optical signal having a wavelength λ ₂ emitted from the third optical fiber 9 is dispersed in the cross section of the third optical fiber 9, passes through the lens 6-2, passes through the filter 5, and then the lens The light is collected while passing through 6-1 and enters the second optical fiber 2. Therefore, the light having the optical signals having the wavelengths λ ₁ and λ ₂ is combined with the second optical fiber 2 to proceed. The first optical fiber 1 and the third optical fiber 9 are respectively connected to optical signal generating means for generating light having an optical signal of wavelength λ _{1 and} an optical signal of wavelength λ ₂ , which are not shown.

Operation of another embodiment of the photosynthetic splitter of the present invention will be described in detail with reference to FIG. Light having an optical signal of wavelength λ _{1 and} an optical signal of wavelength λ ₂ emitted from the second optical fiber 2 is dispersed in the cross section of the second optical fiber 2 and passes through the lens 6-1, and the filter 5 Light having an optical signal of λ ₁ is reflected and light having an optical signal of wavelength λ ₂ is transmitted. The light having the optical signal of λ ₁ reflected from the filter 5 is collected by passing through the lens 6-1 again and enters the first optical fiber 1. On the other hand, light having an optical signal of λ ₂ transmitted through the filter 5 is collected while passing through the lens 6-2 and enters the third optical fiber 9. Therefore, light having an optical signal of wavelength λ _{1 and} an optical signal of wavelength λ ₂ introduced through the second optical fiber 2 is separated into the first optical fiber 1 and the third optical fiber 9 to detect each optical signal. Proceed by means (not shown).

Referring back to Figure 4, it looks at with respect to the assembly and adjustment of the photosynthetic splitter of the present invention. The adjustment of the optical axis or the optical path between components in the optical splitter is very important because the device cannot be used unless the alignment of the optical axis is satisfactory. In the photosynthesis splitter of the present invention, since the filter 5 is attached to the first lens holder 4-1 in advance, it is not necessary to adjust the filter 5 separately. Therefore, the adjustment at the time of assembly with respect to the photosynthesis spectrometer of the present invention is that each lens 6-1, 6-2 is assembled to the lens holder 4-1, 4-2, and again the lens holder 4 -1) (4-2) is made only for the ferrule 3 and the ferrule 8 with the body 7 assembled.

In the assembly of the photosynthesis spectrometer of the present invention, the lenses 6-1 and 6-2 are first pressed into the respective lens holders 4-1 and 4-2, and then the filter 5 is attached to the first lens holder. Attach it to (4-1) and assemble it to the body. When the assembly is completed, the ferrule 3 in which the first optical fiber 1 and the second optical fiber 2 are embedded is adjusted in the x-y direction perpendicular to the optical axis. At this time, the ferrule 3 does not need to be adjusted in the circumferential direction, that is, in the rotational direction. Similarly, the ferrule 8 in which the third optical fiber is embedded is adjusted in the x-y direction to complete the assembly of the photosynthetic splitter of the present invention.

In addition to the embodiments described above, three optical fibers may be embedded in the first ferrule 3. One additional optical fiber can be used for various purposes. For example, the extra optical fiber may be used to apply a certain signal for modifying or modifying a specific optical signal for the purpose of communication security, etc., and may also be used for applying a specific control signal. Of course, further optical fibers may be embedded as needed, and positions optically symmetric with respect to the center of the cross section of the ferrule may be selected as the embedding positions.

As can be seen from the above description, the optical communication optical splitter of the present invention is basically simple in structure and low in number of parts, so that not only the assembly is easy but also the optical axis and the like can be easily adjusted. Therefore, the photosynthetic splitter of the present invention has low manufacturing cost, high accuracy, and low failure rate.

Claims (14)

Body having a hollow for accommodating the component. A first optical fiber and a second optical fiber, and an optical signal of a first wavelength and a first optical fiber, each of which is a movement path of an optical signal and connected to an optical signal generating means having a light emitting element for generating an optical signal of a first wavelength and an optical signal of a second wavelength A third optical fiber in which two wavelengths of optical signals travel, a first ferrule in which a part of the first optical fiber and a second optical fiber are embedded, and a part of which is inserted in the body, and the third optical fiber is embedded in the body A second ferrule in which part thereof is inserted. Two lenses for condensing light having an optical signal, a filter having a characteristic of reflecting light having an optical signal of a first wavelength and transmitting light having an optical signal of a second wavelength, one of the lenses and the filter An optical splitter comprising: a first lens holder, and a second lens holder provided with a lens. The optical splitter according to claim 1, wherein said filter is attached to a second lens holder. The optical splitter according to claim 1, wherein the lens is a gradient index lens. 2. The photosynthesis splitter according to claim 1, wherein the first ferrule has three or more optical fibers. The optical splitter according to claim 1, wherein the lens is a spherical lens. The optical splitter according to claim 1, wherein the lens is a drum lens. 7. An optical splitter according to claim 5 or 6, wherein each ferrule has an end of the optical fibers embedded therein by a focal length of the lens from an end of the ferrule in contact with the lens holder. A first optical fiber connected to an optical signal detecting means having a body having a hollow portion for accommodating components, each of which is a movement path of an optical signal and has an optical sensing element for sensing an optical signal of a first wavelength and an optical signal of a second wavelength; A first optical fiber in which a second optical fiber, a third optical fiber having a first wavelength optical signal and a second wavelength optical signal, and a first optical fiber and a second optical fiber are embedded and a part of which is inserted into the body; And a second ferrule in which the third optical fiber is embedded and a part of which is inserted into the body, two lenses focusing the light having the optical signal, and reflecting the light having the optical signal having the first wavelength and reflecting the second wavelength. And a filter having a characteristic of transmitting light having an optical signal, a first lens holder provided with one of the lenses, and a second lens holder provided with the lens. The optical splitter according to claim 8, wherein the filter is attached to the second lens holder. The optical splitter according to claim 8, wherein the lens is a gradient index lens. The optical splitter according to claim 8, wherein the first ferrule has three or more optical fibers. The optical splitter according to claim 8, wherein the lens is a spherical lens. 9. The photosynthesis splitter according to claim 8, wherein said lens is a drum lens. The optical splitter according to claim 12 or 13, wherein each ferrule has an end of the optical fibers embedded therein by an focal length of the lens from an end of the ferrule in contact with the lens holder.