KR100744457B1 - Add/Drop Multiplexer having High Isolation Value - Google Patents

Abstract

The optical insertion extractor according to the present invention includes a first optical transmission unit including first to third optical paths for transmitting and receiving optical signals, and at least one optical element for concentrating optical signals received through the first optical transmission unit into linear light. At least one optical device for converging the optical signal received through the second optical transmission unit and the second optical transmission unit having a first optical focusing apparatus comprising a, and the fourth and fifth optical paths for transmitting and receiving the optical signal to the linear light A second optical concentrator including; first and second filters for transmitting / reflecting an optical signal corresponding to a wavelength region of the optical signal input through the first and second optical concentrators, respectively; And first and second mirrors for reflecting the optical signal transmitted through each of the two filters to the first and second filters, wherein any one of the optical paths of the first optical transmission unit and one of the optical paths of the second optical transmission unit are interconnected. Been reminded First filter and directs the optical signal reflected by the first mirror to the second light focusing device.

WDM, ADM. Optical insertion extractor, isolation, insertion loss, optical communication

Description

Add / Drop Multiplexer having High Isolation Value}

1 is a schematic diagram showing a conventional optical communication technology,

Figure 2 is a schematic diagram showing a conventional optical insertion extractor,

Figure 3 is a graph showing the isolation value when using a conventional light insertion extractor alone,

4 is a schematic view showing a case where a plurality of conventional optical insertion extractors are constructed;

5 is a graph showing an isolation value when a plurality of conventional optical insertion extractors are used;

Figure 6 is a schematic diagram showing another case composed of a plurality of conventional optical insertion extractor,

7 is a schematic view showing an optical insertion extractor of the present invention;

8 is a graph showing an isolation value when using the optical insertion extractor according to the first embodiment of the present invention;

Figure 9 is a graph showing the isolation value when using the optical insertion extractor according to the second embodiment of the present invention.

＊ Description of Signs of Major Parts in Drawings ＊

30: optical insertion extractor 31: housing

32: first light focusing device 33: second light focusing device

34: first filter 35: second filter

36: first mirror 37: second mirror

41: first optical path (input) 42: second optical path (output)

43: third optical path (output) 44: fourth optical path (input)

45: fifth optical fiber line (output)

The present invention relates to an optical insertion extractor, and more particularly, to an optical insertion extractor for inserting / extracting an optical signal of multiple channels in an optical communication system of a wavelength division multiplexing method.

In general, optical communication using a wavelength division multiplex (WDM) scheme, as shown in FIG. 1, transmits an optical signal between an MUX / DeMUX, an optical cable connecting the same, and an MUX and DeMUX. Optical Add / Drop Multiplexer for Drop.

The structure of the optical insertion extractor 10 for transmitting such a conventional multi-channel optical signal is shown in FIG. Here, the light insertion extractor 10 indicates an ADM having a single filter.

The conventional optical insertion extractor 10 shown in FIG. 1 includes a housing 11 in a longitudinal direction, a first light focusing device 12 and a second light focusing device 13 fixedly installed at both sides of the housing 11. And one filter 15 disposed between the first and second light focusing devices 12 and 13. Here, the filter 15 is a band pass filter for transmitting an optical signal corresponding to a predetermined wavelength region among the optical signals incident through the input optical path 18 and the first lens 12b and reflecting other optical signals. (band pass filter) or an optical signal corresponding to a wavelength region larger or smaller than a predetermined wavelength is transmitted, and other optical signals are configured in the form of an edge filter having a characteristic of reflecting.

The first optical focusing apparatus 12 includes a first optical transmission unit (hereinafter referred to as a 'first pigtail') 12a and a first lens having one input optical path 18 and one output optical path 16. (12b). In addition, the second light concentrator 13 has a second light transmission unit (hereinafter referred to as a 'second pigtail') 13a and a second lens 13b having one output light path 17.

In this case, each of the input optical line 18 and the output optical line (16, 17) is made of an optical fiber, the input optical line 18 is a dashed line, the output optical line (16, 17) is a two-point chain, The light paths are respectively shown by solid lines.

Hereinafter, an optical signal path of the three-port optical insertion extractor 10 will be described with reference to FIG. 1. First, an optical signal having a predetermined wavelength region incident on the first lens 12b via the input optical path 18 is focused onto the filter 15 by the first lens 12b.

The filter 15 transmits the preset first wavelength region and reflects the other second wavelength region. Accordingly, the first wavelength region passing through the filter 15 is focused by the second lens 13b to the second pigtail 13a and transmitted through the output optical line 17, and is reflected by the filter 15. The second wavelength region is focused through the first lens 12b and transmitted through the output optical line 16.

In this case, the optical signal passing through the filter 15 is transmitted by mixing a second wavelength region in addition to the first wavelength region, and slightly in addition to the second wavelength region reflected in the case of the optical signal reflected by the filter 15. The first wavelength region of is mixed and reflected.

As such, the smaller the wavelength range other than the preset wavelength range during transmission and reflection, the higher the isolation value, which is an important factor that determines the performance of the optical insertion extractor. As shown in FIG. 3, the isolation value may be divided into isolation M1 at reflection and isolation M2 at transmission. Here, the isolation M1 value in reflection is represented by the difference between the maximum insertion loss value in the first wavelength region and the minimum insertion loss value in the second wavelength region in the reflection curve, and the isolation M2 value in transmission is the first wavelength. It is represented by the difference between the minimum insertion loss value in the region and the maximum insertion loss value in the second wavelength region.

On the other hand, sometimes you want a high isolation value. This is because when the signals of different wavelengths are separated into respective wavelengths, the signals of one wavelength overlap with the signals of one wavelength to act as noise. In order to minimize such noise, there is a method of using a filter having a high isolation value, but due to the limitation of the filter manufacturing technology, it does not satisfy the user's satisfaction. However, it is noted that the isolation value as described above increases as the number of reflection and transmission increases, and in order to have a better isolation value than the limit of the filter, the optical insertion extractor outputs an optical signal after a plurality of reflection and transmission are performed. It is common to install in multiple numbers.

4 and 6 illustrate an example of using a plurality of light insertion extractors as described above. First, the light insertion extractors 10 and 20 shown in FIGS. 4 and 6 are all provided with a single edge filter 15 and 25, each of which has a structure of the light insertion extractor 10 shown in FIG. Same as the structure.

First, in the case of using the plurality of light insertion extractors 10 and 20 as shown in FIG. 4, the following differences occur as compared to the case of using a single light insertion extractor 10. In the case of using a single optical insertion extractor 10, the optical signal of the second wavelength region is reflected through the filter 15 and then output through the output optical line 16, but as shown in FIG. In the case of using (20), the optical signal of the second wavelength region is reflected after the first optical insertion extractor 10 and then transmitted after passing through the filter 25 of the second optical insertion extractor 20. Accordingly, as shown in FIG. 5, the value of the isolation M3 upon reflection is larger than when using a single light input extractor 10 (M1; see FIG. 3).

 On the other hand, Figure 6 shows a case of using the four light insertion extractors (10, 20). According to this, the optical signal of the first wavelength region is transmitted after passing through the first optical inserter 10, and then output again after passing through the optical insertion extractor 10 of the same structure, the optical signal of the second wavelength region is the first optical insertion After being reflected from the extractor 10, the two light insertion extractors 20 are sequentially transmitted and then output. That is, the optical signal of the first wavelength region is output through two transmissions, and the optical signal of the second wavelength region is output through one reflection and two transmissions. Accordingly, both reflection / transmission isolation values M3 and M4 (see FIG. 5) become larger than those of FIG. 4 as well as the case of FIG. 2.

As described above, when a plurality of light insertion extractors are used together, it can be seen that the isolation value is higher than when using a single light insertion extractor.

However, in this case, the number of parts is increased, the manufacturing labor and manufacturing cost is increased, there is a problem that it is difficult to obtain a compact product due to the large volume. In addition, as the magnitude of the insertion loss generated when the optical signal passes through the light concentrators 12 and 13 installed in the respective optical insertion separators increases, the power of the optical signal that is finally separated decreases, which is disadvantageous in using the optical signal. Is also generated. Therefore, it is necessary to solve the above-mentioned conventional problems and to further reduce the insertion loss as well as to increase the isolation value.

An object of the present invention for solving the above problems is to provide a light insertion extractor that can obtain a high isolation value while reducing the manufacturing labor and manufacturing cost.

The optical insertion extractor according to the present invention for achieving the above object, the first optical transmission unit having first to third optical paths for transmitting and receiving optical signals, and the optical signal received through the first optical transmission unit as a linear light A first light focusing device comprising at least one optical element for focusing; A second optical focusing apparatus including a second optical transmission unit having fourth and fifth optical paths for transmitting and receiving optical signals and at least one optical element for focusing the optical signal received through the second optical transmission unit into linear light; First and second filters transmitting and reflecting the optical signal in response to a wavelength region of the optical signal input through the first and second optical focusing devices, respectively; And first and second mirrors for reflecting optical signals transmitted through the first and second filters to the first and second filters, respectively, and any one of the optical paths of the first optical transmission unit and the second optical transmission. One of the negative optical paths is interconnected to guide the optical signal reflected by the first filter and the first mirror to the second optical focusing apparatus.

According to a preferred embodiment of the present invention, the first filter and the second filter is preferably composed of a filter for filtering different wavelength ranges.

The first filter and the second filter may be edge filters, and the second filter may be a filter through which an optical signal reflected from the first filter may be transmitted.

Here, the first optical path and the fourth optical path is an input optical path, and the second optical path, the third optical path and the fifth optical path are output optical paths, and the third optical path and the fourth optical path are more preferably fused and connected to each other. Do.

Hereinafter, the configuration of an optical insertion extractor having a high isolation value according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

7 shows an optical insertion extractor according to an embodiment of the present invention. Referring to this, the optical insertion extractor 30 according to the present invention includes a first light concentrator 32, a second light concentrator 33, first and second filters 34 and 35, and First and second mirrors 36 and 37.

The first optical focusing device 32 includes first to third optical paths 41 and 42 and 43, a first lens 32b for focusing an optical signal, and first to third optical paths ( 41, 42, 43 and one side of the housing 31 of the optical insertion extractor 30 by including a first light converging portion 32a for enabling transmission and reception of an optical signal. To allow the transmission and reception of optical signals. The first light concentrator 32 may be fixed to one side of the housing 31 by various methods such as epoxy bonding, soldering, or laser welding. For reference, the first optical path 41 is in charge of a path through which an optical signal is transmitted from an optical transmitter (not shown).

The second optical focusing apparatus 33 is configured to focus an optical signal transmitted and received through the fourth optical path 44 and the fifth optical path 45 and the fourth and fifth optical paths 44 and 45. By including a second lens 33b, and the second light converging portion 33a for connecting the fourth and fifth optical paths 44, 45 and the second lens 33b to enable optical signal transmission and reception, The other side of the housing 31 of the insert extractor 30 to enable the transmission and reception of the optical signal. Like the first light concentrator 32, the second light concentrator 33 may be fixed to one side of the housing 31 by various methods such as epoxy bonding, soldering, or laser welding. . For reference, the first and second lenses 32b and 33b used in the first and second light focusing devices 32 and 33 are first to fifth optical paths 41, 42, 43 ( If the condensation of the optical signal transmitted and received through 44) (45) is possible, various configurations can be made using known techniques, and thus a detailed description thereof will be omitted. Meanwhile, in FIG. 5, the first optical path 41 and the fourth optical path 44 indicated by dashed-dotted lines are input optical paths, and the second optical path 42 and the third optical path 43 indicated by double-dotted lines. And the fifth optical path 45 is an output optical path. Among these, the second optical path 42 and the fourth optical path 44 are connected to each other by a connection method such as fusion.

The first and second filters 34 and 35 are configured as edge filters for transmitting optical signals of different wavelength bands, each of which is transmitted through the first and second optical concentrators 32 and 33. Transmit / reflect the optical signal For example, in the present embodiment, the first filter 24 is composed of a filter that transmits an optical signal having a wavelength of 1500 nm and the second filter 25 has a wavelength having a wavelength of 1300 nm.

The first and second mirrors 36 and 37 reflect the optical signals transmitted through the first and second filters 34 and 35 back to the first and second filters 34 and 35. These, first and second filters 34, 35 and first and second mirrors 36, 37 are fixed through epoxy curing or UV curing.

It describes the operation of the optical insertion extractor according to an embodiment of the present invention configured as described above.

First, when an optical signal in which optical signals having two different wavelength regions are combined is incident on the first filter 24 via the first optical path 41, the first filter 24 is formed as shown in FIG. 5. The optical signal in one wavelength region is reflected by the second optical path 42, and the optical signal in the second wavelength region is transmitted. The optical signal of the second wavelength region transmitted through the first filter 24 is reflected to the first filter 24 after being incident on the first mirror 36 and then reflected on the first filter 24. Is output through the third optical path 43. That is, the optical signal in the second wavelength region is output after the first filter 24 and the first mirror 36 are transmitted twice by the first filter 24.

On the other hand, the optical signal reflected by the second optical path 42 is guided to the second filter 25 via the fourth optical path 44. Since the second filter 25 is configured to transmit an optical signal in the first wavelength region, the optical signal incident on the second filter 25 passes through the second filter 25 to allow a second mirror ( 27). The optical signal in the first wavelength region incident on the second mirror 27 is reflected back to the second filter 25, and the optical signal reflected on the second filter 25 is output through the fifth optical path 45. do. That is, the optical signal in the first wavelength region is output after reflection by the first filter 24 and two transmissions by the second filter 25 are performed.

Transmission / reflection insertion loss of the optical insertion extractor 30 according to the present invention configured as described above is as shown in FIG. In the present invention, since the optical signals of the first wavelength region and the second wavelength region are output through a plurality of transmissions and reflections, the difference M1 'of the reflection insertion loss and the difference M2' of the transmission insertion loss are shown in FIG. 8. It is formed in a size similar to a conventional configuration as shown in FIG. That is, even with only one optical insertion extractor 30 of the present invention, it is possible to obtain an isolation value similar to when installing a plurality of optical insertion extractors 10 and 20 (see FIG. 6).

The optical insertion extractor 30 according to the present invention as described above is not necessarily limited to the present embodiment. For example, the first filter 24 and the second filter 25 may be installed to be interchanged with each other. In this case, the optical signal in the first wavelength region is output through the third optical path 43, and the optical signal in the second wavelength region sequentially crosses the second, fourth and fifth optical beams 42, 44 and 45. Output via Transmission / reflection insertion loss of the optical insertion extractor 30 according to another embodiment of the present invention is as shown in FIG. 6, the reflection / transmission insertion loss M1 " M2 " is shown in FIG. 8 even though the positions of the filters 34 and 35 are changed as described above. It is formed to a size similar to the size of the penetration insertion loss M1 'and M2'. As a result, the respective isolation values may be similarly displayed to produce the same effects as in the foregoing exemplary embodiment.

According to the present invention described above, it is possible to improve the filtering performance by obtaining a high isolation while employing a single light insertion extractor, greatly reducing the number of parts as a whole, greatly reducing the production cost by reducing the volume and labor You can do it.

While the invention has been shown and described with respect to preferred embodiments for illustrating the principles of the invention, the invention is not limited to the construction and operation as shown and described. Rather, those skilled in the art will appreciate that changes and modifications can be made to the present invention without departing from the spirit and scope of the appended claims. Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

Claims (5)

A first light concentrating device including a first optical transmission unit including first to third optical paths for transmitting and receiving an optical signal, and at least one optical element for focusing the optical signal received through the first optical transmission unit into linear light. ; A second optical focusing apparatus including a second optical transmission unit having fourth and fifth optical paths for transmitting and receiving optical signals and at least one optical element for focusing the optical signal received through the second optical transmission unit into linear light; First and second filters transmitting and reflecting the optical signal corresponding to the wavelength region of the optical signal inputted through the first and second optical focusing devices, respectively; And And first and second mirrors for reflecting the optical signal transmitted through each of the first and second filters to the first and second filters. The first filter and the first mirror and the second filter and the second mirror are each composed of a pair and arranged symmetrically with each other, Either one of the optical paths of the first optical transmission unit and one of the optical paths of the second optical transmission unit are interconnected to guide the optical signal reflected by the first filter and the first mirror to the second optical focusing apparatus. Light insertion extractor characterized in that. The optical insertion extractor of claim 1, wherein the first filter and the second filter filter different wavelength regions. The optical insertion extractor of claim 2, wherein the first filter and the second filter are edge filters. The method of claim 3, wherein And the second filter is a filter through which an optical signal reflected from the first filter can be transmitted. The method according to any one of claims 1 to 4, The first optical path and the fourth optical path are input optical paths, the second optical path, the third optical path and the fifth optical path are output optical paths, And a third optical path and a fourth optical path are fusion-spliced to each other.

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