KR100701728B1 - Wavelength dependant optical device - Google Patents

Abstract

The present invention relates to a wavelength dependent optical device. According to the present invention, a dual collimator for receiving an optical signal through an optical fiber and converts it into a plane wave; A filter installed independently of the dual collimator and receiving an optical signal from the dual collimator to selectively transmit a specific wavelength; A single collimator for outputting an optical signal transmitted from the filter; And a housing for optically aligning and fixing the dual collimator, the filter, and the single collimator, wherein the filter is fixed to a filter seat coupled to the housing so as to be interposed between the dual collimator and the single collimator. A dependent optical element is disclosed. Accordingly, in the wavelength dependent optical device, the filter may be installed so as not to be dependent on the dual collimator, and the use of the epoxy may be excluded when the filter is installed, thereby preventing the optical axis alignment change of the optical device due to external environment changes such as temperature or humidity.

Optical element, collimator, filter, photo detector

Description

Wavelength dependent optical device TECHNICAL FIELD

The following drawings attached to this specification are illustrative of preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to.

1 is a cross-sectional view showing a wavelength dependent filter according to the prior art.

Figure 2 is a cross-sectional view showing a wavelength dependent light receiving device according to the prior art.

3 is a sectional view schematically showing a wavelength dependent optical element according to a preferred embodiment of the present invention.

4 is a perspective view illustrating a wavelength dependent optical element and a filter unit employed therein according to FIG. 3.

5 is a cross-sectional view showing a filter portion employed in accordance with another embodiment of the present invention.

Fig. 6 is a sectional view showing a filter portion employed in accordance with another embodiment of the present invention.

Fig. 7 is a sectional view schematically showing a wavelength dependent optical element according to another embodiment of the present invention.

FIG. 8 schematically illustrates a photo detector employed in an optical device according to another embodiment of the present invention. FIG.

9 is a graph showing the change in the amount of received light according to the spacing of the lens and the photodiode of the photodetector employed in the optical device according to the present invention.

<Explanation of symbols for the main parts of the drawings>

110 ... dual collimator 120 ... single collimator

130 filter unit 131 filter unit

132 filter housing 140 housing

160 ... Photo Detector

The present invention relates to a wavelength dependent optical device, and more particularly, to a wavelength dependent optical device that minimizes damage to optical alignment due to external environment.

In recent years, the exponential growth of information communication demands high speed transmission network, and large capacity optical transmission technology is needed. Optical transmission technology has developed in the direction of high speed such as 56 Mbps, 1.2 Gbps, 10 Gbps, etc. in response to the increase in information communication volume. Multiplexer: hereafter divided into WDM).

However, due to technical limitations, the TDM method can only support a transmission rate of up to 40 Gbps, and thus the optical signal transmission technology between stations is developing into a wavelength division WDM method capable of implementing Tbps-class transmission speeds. The WDM method transmits several optical signals with slightly different wavelengths in one optical waveguide through one optical fiber, and enables the flow of several signals having different wavelength bands in one optical fiber without installing additional optical fibers. There is an advantage that can increase the transmission capacity of the existing optical fiber. In order to transmit an optical signal using the WDM method, a wavelength processing element capable of selectively transmitting a wavelength and returning the rest to a traveling direction or adding a wavelength containing a new signal is required.

1 shows a wavelength dependent filter as an example of a conventional wavelength processing element. Referring to FIG. 1, a wavelength-dependent filter according to the related art receives a specific signal region in an optical signal output from a dual collimator 10 and a dual collimator 10 that receive an optical signal transmitted through an optical fiber at an input terminal and convert it into a plane wave. The filter 31 selectively transmits only the optical signal of and a single collimator 20 for transmitting the filtered optical signal to the optical fiber of the output terminal. The dual collimator 10 and the single collimator 20 are fixed to the housing 40 using soldering (51, 52).

In addition, FIG. 2 illustrates a wavelength dependent light receiving device as another example of a conventional wavelength processing device. Referring to FIG. 2, the wavelength dependent light receiving device according to the related art has a structure in which the single collimator 20 of the aforementioned wavelength dependent filter is replaced by the photo detector 60 and simultaneously performs filtering and photoelectric conversion of an optical signal.

In the case of the wavelength-dependent optical device according to the related art, the filter settling unit 32 on which the filter 31 is placed is bonded to the dual collimator 10 using an epoxy 53 and subordinated to the dual collimator 10.

However, the epoxy 53 is susceptible to changes in temperature and humidity. Therefore, the optical device according to the prior art may damage the optical alignment of the optical device when the epoxy is deformed by the environmental factors. That is, since the filter 31 is dependent on the epoxy 53 to the dual collimator 10, the deformation caused by the environmental change of the filter setter 32 may optically affect the reflection end and the output end of the dual collimator 10. Can give Therefore, a reliable optical device could not be provided.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a wavelength dependent optical device in which a filter is configured independently of a dual collimator so that optical axis alignment of the optical device is not affected by an external environment.

Another object of the present invention is to provide a wavelength dependent optical device capable of improving the optical coupling efficiency when the photodetector is included in the optical device, thereby increasing the photoelectric conversion rate even when a collimated light source is incident.

Wavelength-dependent optical device according to the present invention for achieving the above object is a dual collimator for receiving an optical signal through the optical fiber and converts it into a plane wave; A filter installed independently of the dual collimator and receiving an optical signal from the dual collimator to selectively transmit a specific wavelength; A single collimator for outputting an optical signal transmitted from the filter; And a housing for optically aligning and fixing the dual collimator, the filter and the single collimator, wherein the filter is fixed to a filter set coupled to the housing so as to be interposed between the dual collimator and the single collimator. .

Preferably, the housing and the filter settle can be assembled by soldering or welding.

The filter settled portion may be inserted into and fixed to the housing through an opening provided in an outer circumferential surface of the housing.

Alternatively, the filter settlement part may be inserted into the inner hollow of the housing, and may be fixed to the housing by soldering or welding using a through hole provided on an outer circumferential surface of the housing, or may be fixed to the housing by fastening a bolt to the through hole.

In another alternative, the housing is composed of a first housing to which the dual collimator is coupled and a second housing to which the single collimator is coupled, and the first and second housings may be installed and fixed to both sides of the filter setter.

According to another aspect of the invention, the dual collimator for receiving an optical signal through the optical fiber and converts it into a plane wave; A filter installed independently of the dual collimator and receiving an optical signal from the dual collimator to selectively transmit a specific wavelength; A photo detector converting the optical signal transmitted from the filter into an electrical signal; And a housing for optically aligning and fixing the dual collimator, the filter, and the photo detector, wherein the filter is fixed to a filter seat coupled to the housing so as to be interposed between the dual collimator and the single collimator. A wavelength dependent optical element is provided.

Preferably, the photo detector includes a lens and a photodiode, and the distance between the lens and the photodiode may be adjusted so that a maximum amount of optical signals are received by the photodiode.

According to the present invention, the distance between the lens and the photodiode is preferably 0.35mm to 0.65mm.

More preferably, the distance between the lens and the photodiode may be 0.4mm to 0.5mm.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the common or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

3 is a view schematically showing a wavelength dependent optical device according to a preferred embodiment of the present invention.

Referring to FIG. 3, the wavelength dependent optical device according to the present exemplary embodiment includes a dual collimator 110 that receives an optical signal transmitted through an input side optical fiber and converts the optical signal into a plane wave, and selectively only an optical signal having a wavelength band required by the smoothed optical signal. It includes a filter unit 130 for transmitting, a single collimator 120 for outputting the optical signal transmitted from the filter unit 130 and the housing 140 surrounding the collimator (110, 120) and the filter unit 130.

The dual collimator 110 includes a capillary and a lens. The capillary fixes the optical fiber to the dual collimator 110 while maintaining a constant distance between the optical fiber of the two strands connected to the input terminal and the reflecting end. Preferably the capillary maintains the spacing of the optical fiber to 125um.

The lens refracts the optical signal so that the optical signal input from the optical fiber matches the focus of the filter unit 130 and converts the optical signal into a plane wave. Preferably, the lens is a rod-shaped green lens having a refractive index distribution, such as a graded optical fiber.

The single collimator 120 is provided on the opposite side of the dual collimator 110 as an output port for outputting an optical signal incident from the dual collimator 110 and transmitted to the filter unit 140.

On the other hand, the dual collimator 110 and the single collimator 120 is preferably provided with a metal shell layer on the outer peripheral surface to facilitate the bonding with the housing (40).

The filter unit 130 is provided to be interposed independently between the dual collimator 110 and the single collimator 120. The filter unit 130 includes a filter 131 for selectively passing wavelengths of the optical signal input from the dual collimator 110 and a filter setter 132 for spatially fixing the filter 131.

Preferably, the filter 131 is a band pass filter and is composed of a filter in which one or more thin films are stacked. The filter settled portion 132 is fixed to the housing 140.

Referring to FIG. 4 with reference to FIG. 3, the filter unit 130 will be described in more detail. The filter 131 is prepared in a fixed state to the filter settlement unit 132, and the filter setter unit 132 has a housing ( And a length corresponding to the diameter of 140). In addition, an opening 141 is provided on an outer circumferential surface of the housing 140. The opening 141 is preferably provided at a suitable position to be interposed between the dual collimator 110 and the single collimator 120 installed in the housing 140. After inserting and installing the filter settled portion 132 in which the filter 131 is fixed to the opening 141 of the housing 140, the joints are connected to each other using lead so that the bonding strength is not changed by an external mechanical force. Finish with soldering 153 or welding.

5 is a cross-sectional view showing a filter unit employed in a wavelength dependent optical element according to another embodiment of the present invention. In FIG. 5, the same reference numerals as in the above-described drawings indicate the same members having the same function and detailed description thereof will be omitted.

Referring to FIG. 5, the filter unit 330 includes a filter 331 and a filter settlement unit 332 for fixing the filter. The filter part 330 is installed by being inserted into the inner hollow of the housing. Therefore, the size of the filter settlement portion 332 is preferably configured to correspond to the inner diameter of the housing. At this time, the position where the filter unit 330 is installed is interposed between the dual collimator 110 and the single collimator 120. Thereafter, the filter unit 330 is fixed to the housing.

Preferably, the outer circumferential surface of the housing 340 is provided with a through hole 333 to correspond to the insertion position of the filter unit 330. After the filter unit 330 is inserted, the filter seat 332 and the housing 340 are fixed by soldering or welding using the through hole 333. Alternatively, the housing 340 and the filter seat 332 may be fixed by fastening a bolt to the through hole 333 provided on the outer circumferential surface of the housing 340.

More preferably, at least one through hole 333 may be provided such that the coupling between the housing 340 and the filter unit 330 is more robust. Although the specific configuration of the fixing means has been disclosed in the present embodiment, the present invention is not limited thereto and may be variously modified and employed by those skilled in the art.

6 is a cross-sectional view showing the filter unit 430 employed in the wavelength dependent optical device according to another embodiment of the present invention. In FIG. 6, the same reference numerals as in the above-described drawings indicate the same members having the same functions, and detailed description thereof will be omitted.

Referring to FIG. 6, the housing is composed of a first housing 441 and a second housing 442. The first housing 441 is coupled to the dual collimator 110, the second housing 442 is coupled to the single collimator 120. The first and second housings 441 and 442 are fitted in both sides with the filter settlement portion 432 fixed with the filter 431 therebetween. The inner diameter of the filter unit 430 is preferably configured to correspond to the outer diameter of the housing. Thereafter, the contact surfaces of the housings 441 and 442 and the filter settlement portion 432 are soldered 453 or welded, respectively, to fix the housings 441 and 442 and the filter settlement portion 432.

When the filter 131 is provided independently of the dual collimator 110 as described above, a change according to an external environment that may occur in the filter unit 130 may optically affect the input terminal or the reflective end of the dual collimator 110. To prevent it. In particular, since packaging the filter settlement 132 using soldering or welding, it is possible to effectively prevent damage to the optical alignment, unlike the prior art that the filter dependent on the dual collimator using an epoxy sensitive to temperature or humidity changes.

On the other hand, the housing 140, 340, 440 is fixed to the collimator (110, 120) and the filter unit in the optical axis alignment state. The housings 140, 340, and 440 are cylindrical to correspond to the shape of the collimators 110 and 120, and are preferably made of metal to facilitate soldering or welding.

7 is a view schematically showing a wavelength dependent optical device according to another aspect of the present invention. In FIG. 7, the same reference numerals as in the above-described drawing indicate the same members having the same functions, and detailed description thereof will be omitted.

Referring to FIG. 7, in the wavelength dependent optical device according to the present exemplary embodiment, a photo detector 160 is provided on the opposite side of the dual collimator 110.

The photo detector 160 detects and converts an optical signal into an electrical signal by using a photovoltaic effect, a photoconductive effect, or a photoelectron emission phenomenon on a photoelectric surface of a semiconductor device. Therefore, by providing the photo detector 160, the wavelength dependent optical element can function as a wavelength dependent light receiving element.

The photo detector 160 includes a lens 161 and a photo diode 162 as shown in FIG. 8. The distance D between the lens 161 and the photodiode 162 may be appropriately adjusted to increase the coupling efficiency of the optical signal passing through the filter 131 and the photo detector 160.

9 is a graph illustrating the coupling efficiency of the optical signal according to the distance between the lens 161 and the photodiode 162.

9, an optimal photoelectric conversion rate may be obtained when the distance D between the lens 161 and the photodiode 162 is preferably 3.5 to 6.5 mm, more preferably 4 to 5 mm.

On the other hand, in the case of the wavelength-dependent optical device having a photo detector 160, the configuration of the filter unit is not limited to that shown in Figure 7, it is a matter of course that can be variously modified as shown in FIG.

Hereinafter, a method of assembling a wavelength dependent optical element having the above configuration will be described.

First, the filter settled part in which the filter is fixed according to each of the above-described embodiments is installed in the housing. Then package the filter settlement and housing from the outside by soldering.

The dual collimator 110, the single collimator 120 or the photo detector 160 is inserted into the housing 140 in a state fixed to the alignment jig (not shown) to align the optical axis. At this time, the optical measuring device is used to find the optimal position where the light loss can be minimized.

Then, between the dual collimator 110 and the housing 140, and between the single collimator 120 or photodetector 160 and the housing 140 by soldering (151, 152) or welding (welding). As a result, the inside of the optical device can be blocked from the outside, and the change of the optical axis alignment state of the device due to temperature and humidity changes can be minimized.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto and is intended by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

As described above, in the wavelength-dependent optical device, the filter is installed so as not to be dependent on the dual collimator, and the use of epoxy is eliminated when the filter is installed, thereby changing the optical axis alignment of the optical device due to external environment such as temperature or humidity. Can be prevented.

In addition, in the optical device including the photo detector, the optical coupling efficiency may be improved by optimizing the distance between the lens and the photodiode to increase the photoelectric conversion rate even when the collimated light source is incident.

Therefore, it is possible to provide a high reliability optical device by improving the performance of the optical device.

Claims (17)

A dual collimator that receives an optical signal through an optical fiber and converts the optical signal into a plane wave; A filter installed independently of the dual collimator and receiving an optical signal from the dual collimator to selectively transmit a specific wavelength; A single collimator for outputting an optical signal transmitted from the filter; And a housing for optically aligning and fixing the dual collimator, the filter and the single collimator. The filter is wavelength-dependent optical element, characterized in that fixed to the filter seat coupled to the housing interposed between the dual collimator and the single collimator. The method of claim 1, And the housing and the filter seat are assembled by soldering or welding. The method of claim 1, wherein the filter settled portion, Wavelength-dependent optical element, characterized in that inserted into and fixed to the housing through the opening provided in the outer peripheral surface of the housing. The method of claim 1, wherein the filter settled portion, The wavelength-dependent optical device, characterized in that inserted into the inner hollow of the housing is fixed to the housing. The method of claim 4, wherein the filter settled portion, Wavelength-dependent optical element, characterized in that fixed to the housing by soldering or welding using a through hole provided on the outer peripheral surface of the housing. The method of claim 4, wherein the filter settled portion, The wavelength-dependent optical device, characterized in that the bolt is fastened to the housing provided in the through hole provided on the outer peripheral surface of the housing. The method of claim 1, The housing is composed of a first housing coupled to the dual collimator and a second housing coupled to the single collimator, The first and second housings are wavelength-dependent optical element, characterized in that installed on both sides of the filter settled. A dual collimator that receives an optical signal through an optical fiber and converts the optical signal into a plane wave; A filter installed independently of the dual collimator and receiving an optical signal from the dual collimator to selectively transmit a specific wavelength; A photo detector converting the optical signal transmitted from the filter into an electrical signal; And a housing for optically aligning and fixing the dual collimator, the filter, and the photo detector. The filter is wavelength-dependent optical element, characterized in that fixed to the filter settled coupled to the housing interposed between the dual collimator and the photo detector. The method of claim 8, And the housing and the filter seat are assembled by soldering or welding. The method of claim 8, wherein the filter settled portion, Wavelength-dependent optical element, characterized in that inserted into and fixed to the housing through the opening provided in the outer peripheral surface of the housing. The method of claim 8, wherein the filter settled portion, And a wavelength dependent optical element inserted into the hollow inside the housing and fixed to the housing. The method of claim 11, wherein the filter settled portion, Wavelength-dependent optical element, characterized in that fixed to the housing by soldering or welding using a through hole provided on the outer peripheral surface of the housing. The method of claim 11, wherein the filter settled portion, The wavelength-dependent optical device, characterized in that the bolt is fastened to the housing provided in the through hole provided on the outer peripheral surface of the housing. The method of claim 8, The housing is composed of a first housing coupled to the dual collimator and a second housing coupled to the photo detector, The first and second housings are wavelength-dependent optical element, characterized in that installed on both sides of the filter settled. The method of claim 8, The photo detector includes a lens and a photo diode, The wavelength-dependent optical element, characterized in that the distance between the lens and the photodiode is adjusted so that the maximum amount of optical signal is received by the photodiode. The method of claim 15, The wavelength-dependent optical device, characterized in that the distance between the lens and the photodiode is 0.35mm to 0.65mm. The method of claim 15, The wavelength-dependent optical device, characterized in that the gap between the lens and the photodiode is 0.4mm to 0.5mm.

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