KR101040316B1 - Optical Bi-directional Transmitting and Receiving Module of Single Wavelength - Google Patents

Abstract

The present invention relates to a single wavelength bidirectional optical transmission / reception module, and more particularly, single wavelength bidirectional optical transmission / reception, which enables a smooth communication by preventing an optical signal output from a transmitter from being directly input to a receiver. It is about a module.

The present invention is a transmitting side laser diode; An optical fiber ferrule for inputting and outputting an optical signal; A splitter transferring the output optical signal to the optical fiber ferrule and reflecting the optical signal input to the optical fiber ferrule down through the optical fiber; A reflector reflecting the reflected light so as not to pass through the splitter to the outside of the module; A reception side photodiode to which an optical signal reflected downward by the splitter is input; It includes.

Accordingly, the present invention prevents the occurrence of noise by preventing the direct light entering from the transmitting end to the outside of the optical module by effectively reflecting some of the reflected light to the outside of the optical module by using a reflector, rather than converging all of the upward light from the transmitting end to the optical fiber. By increasing the sensitivity there is an advantage that can be a smooth optical communication.

Bidirectional, Optical Transceiver, Module, Splitter, Reflector, Window, Fiber Optic Ferrule, Angled

Description

Optical Bi-directional Transmitting and Receiving Module of Single Wavelength

The present invention relates to a bi-directional optical transmission and reception module using a single wavelength, and more particularly, bi-directional optical to enable a smooth communication by preventing the optical signal output from the transmitter from being directly received by the receiver, thereby avoiding the influence of internal noise. It relates to a transmission and reception module.

The bidirectional optical transmission / reception module is a device for transmitting and receiving two or more wavelengths simultaneously using a single optical fiber.

1 illustrates a structure of a general bi-directional (BIDI) optical transmission / reception module using two wavelengths for uplink transmission and downlink reception. Wavelength Division Multiplexing (WDM) edge filters of 'A' are used to separate the two wavelengths required for transmission and reception (ex, transmission: 1310 nm, reception: 1490 nm). In order to prevent input to the receiver, a wavelength division multiplexing edge filter or a band pass filter of 'B' may be selectively used.

In order to communicate using the bidirectional optical transceiver module, a product that needs to be paired with one optical module as shown in FIG. 2 is required. In this optical module, the wavelength of the transmitting end is the same wavelength as the receiving end of the other optical module, and the receiving end wavelength is It is structurally required to be the same as the transmitting end wavelength of the other optical module.

Problems caused by the above structure is as follows.

1) From the point of view of a telecommunications company, the number of products is basically doubled according to the wavelength to be used, which causes complexity of system configuration.

2) For optical module manufacturers, the number of products is doubled, which means that the number of wavelength-related components such as laser diodes (LDs), filters, and isolators has also doubled. Increasing the cost of manufacturing and the complexity of the manufacturing process can lead to an increase in product manufacturing costs.

In order to solve these problems, as shown in FIG. 3, an optical module product using a splitter 'C' for transmitting and reflecting light having a specific wavelength by a predetermined ratio has been developed.

4 is a diagram illustrating a practical example of a bidirectional optical transmission / reception module using a single wavelength using an optical module using the splitter shown in FIG. 3.

In order to take advantage of the advantages of using both up-down communication as a single wavelength in the illustrated module, there are two technical problems to be solved.

Firstly, the upward light from the transmitter is not focused on all of the optical fibers, but partially reflected and goes through an internal incident process directly entering the receiver.

In the case of path 1, the upward light from the transmitting end is reflected on the surface of the splitter C, is matched to the upper apparatus E, and is reflected to the receiving end. In the case of path 2, the upward light from the transmitting end is reflected on the surface of the optical fiber ferrule polishing surface (F) to be matched with the splitter (C) and reflected to the receiving end. When the light of the transmitter is directly incident to the receiver, it acts as an internal noise in communicating with the light incident from the outside, which reduces the reception sensitivity and eventually makes communication with low optical power difficult. The following measures can be taken to prevent direct incidence of the transmitter light into the receiver due to this internal reflection.

First, the apparatus E belonging to the path 1 has a light absorption treatment using a black paint or the like to absorb and extinguish the reflected light, or 2) the shape of the E as a hemispherical shape as shown in FIG. There is a method to allow the light to be dispersed during reflection compared to the instrument having a horizontal plane by processing to have.

The method of using both the light absorption treatment of the apparatus E, the hemispherical appearance, etc. can also be considered.

In order to perform light absorption treatment on the apparatus E belonging to the path 1, black epoxy, black plating apparatus logistics, or black sponge is usually used.In the case of black epoxy, an operator manually applies epoxy to the surface of the apparatus and then hardens it. This is accompanied by a decrease in productivity. In the case of using a black plating apparatus, it is difficult to obtain homogeneous plating performance because it is limited to the brass series because the metal to be plated should be selected based on the characteristics of the optical module without rust. Finally, when applying a black sponge, contamination of the optical module due to residues such as debris becomes a problem.

The more fundamental problem is as follows. Since the light that is not focused on the optical fiber cannot be destroyed 100% even if the absorber and the dispersing device are used, the remaining light eventually moves in the optical module until the energy is consumed and eventually tries to input to the receiving end continuously. This causes noise and causes a decrease in reception sensitivity during communication.

Second, an anti-reflection (AR) coating is applied to the optical fiber ferrule polishing surface F, which is the starting point of reflection of path 2, to reduce the amount of reflection to the receiving end by reducing the reflectance of about 4% to about 1%.

Problems that occur when taking these steps include: In the case of applying an anti-reflection (AR) coating on the ferrule surface, an additional anti-reflection (AR) coating must be applied to the ferrule side of the finished optical fiber, which inevitably leads to an increase in raw material cost.

Secondly, apart from the problem that the upstream light from the above-mentioned transmitter comes from the internal incidence that enters the receiver directly, the externally received light is partially transmitted through the splitter (C) mounted at 45 °. Entering the laser diode (LD) is a problem, which causes the laser diode (LD) of the transmitting end to not reproduce the original signal due to the influence of external noise and to generate an abnormal signal, thereby preventing communication. To solve this problem, an optical isolator (D) is inserted between the LD and the filter stage to block external input light from flowing directly into the LD.

The present invention is to solve the above-mentioned conventional problems, an object of the present invention is that the light for the upstream from the transmitting end is not focused on all the optical fiber to be partially reflected light emitted to the outside of the optical module effectively by using a reflector It is to provide a two-way optical transmission and reception module that prevents direct entry into the receiving end.

In order to achieve the above object, the bidirectional optical transmission / reception module of the present invention comprises: a transmission-side laser diode (10) for outputting an optical signal; An optical fiber ferrule (20) installed in front of the transmitting side laser diode (10) and having one side disposed in front of the transmitting side laser diode (10) and the other side connected to the optical fiber to input and output an optical signal; Between the optical fiber ferrule 20 and the transmitting laser diode 10 is installed to be inclined at an angle up and down with respect to the incident direction of the optical signal output from the transmitting laser diode 10 and the transmitting laser diode 10 A splitter 30 configured to pass an optical signal output from the optical fiber ferrule 20 to reflect the optical signal input to the optical fiber ferrule 20 through the optical fiber; A reflector (40) for reflecting the light reflected by the splitter (30) so as not to pass through the splitter (30) of the optical signal output from the transmitting laser diode (10) to be emitted to the outside of the module; A reception side photodiode 50 installed below the splitter 30 and input to an optical fiber ferrule 20 through an optical fiber to receive an optical signal reflected downward by the splitter 30; Characterized in that comprises a.

In addition, the module is characterized in that it is further provided with a window 60 for passing the light to be emitted to the portion reflected by the reflector 40 to be emitted to the outside of the module and maintains the airtightness of the module. do.

In addition, the window 60 is characterized in that the anti-reflection (AR) coating to prevent the reflection of the light reflected by the reflector 40 is reflected back into the module.

In addition, the reflecting portion 41 of the reflecting portion 40 and the splitter 30 which do not pass through the splitter 30 and reflect the reflected light to be emitted to the outside of the module do not pass through the reflecting portion ( An angle J formed by the light incident on the reflective surface 41 of 40 may be 10 to 50 °.

In addition, the polishing angle (K) of the polishing surface 21 which is one end of the optical fiber ferrule 20 and the central axis of the optical fiber ferrule 20 is characterized in that 78 to 85 °. (As a result, the polishing angle of the ferrule surface is 5 to 12 °.)

In addition, the lens 70 is installed between the splitter 30 and the receiving side photodiode 50 to focus the optical signal reflected downward by the splitter 30 to transmit the optical signal to the receiving side photodiode 50. ; And an isolator 80 which is inputted to the optical fiber ferrule 20 through the optical fiber and is not reflected downward by the splitter 30 and blocks the light passing through the splitter 30 from being transmitted to the transmitting laser diode 10. ); And further comprising:

The present invention prevents the occurrence of noise and prevents the reception sensitivity during communication by preventing the upward light emitted from the transmitter from being focused on all of the optical fibers and partially reflecting the light that is partially reflected to the outside of the optical module by using the reflector. There is an advantage to enable smooth optical communication by raising. As a result, light absorption and light scattering treatments for absorbing and dispersing light that may enter the receiving end do not need to be performed as in the related art, thereby increasing productivity and reducing costs.

Hereinafter, with reference to the accompanying drawings will be described in detail the bidirectional optical transmission module of the present invention.

5 is a perspective view showing the appearance of a bidirectional optical transmission module according to the present invention, Figure 6 is a plan view of a bidirectional optical transmission module according to the present invention, Figure 7 is a front view of a bidirectional optical transmission module according to the present invention, Figure 8 Is AA sectional drawing of FIG. 5, FIG. 9 is BB sectional drawing of FIG. 5, and FIG. 10 is CC sectional drawing of FIG.

Bidirectional optical transmission and reception module 100 of the present invention includes a transmission side laser diode (10) for outputting an optical signal; An optical fiber ferrule 20 having one side disposed in front of the transmitting laser diode 10 and the other side connected to the optical fiber to input and output an optical signal; A splitter 30 installed at an inclined angle up and down and transferring the output optical signal to the optical fiber ferrule 20, and reflecting the optical signal input to the optical fiber ferrule 20 downward through the optical fiber 1; A reflector 40 which does not pass through the splitter 30 and reflects the light reflected by the splitter 30 to the outside of the module; A reception side photodiode 50 to which the optical signal reflected back by the splitter 30 is input; It is made, including.

5 to 7, the bidirectional optical transmission / reception module 100 of the present invention includes a transmitting laser diode 10 at one side of the main body 101, and an optical fiber 1 connected to the other side of the main body 101. A receiving side photodiode 50 is provided below the main body 101.

Referring to the cross-sectional view of Figures 8 to 10 will be described the bidirectional optical transmission module 100 of the present invention.

The transmitting laser diode 10 serves to output an optical signal, and the output optical signal passes through the splitter 30 and is transmitted to the optical fiber ferrule 20 and transmitted through the optical fiber.

The optical fiber ferrule 20 is installed in front of the transmitting laser diode 10, one side is disposed in front of the transmitting laser diode 10 and the other side is connected to the optical fiber to serve to input and output an optical signal.

The splitter 30 is installed between the optical fiber ferrule 20 and the transmitting laser diode 10. In addition, the splitter 30 is inclined at a predetermined angle up and down with respect to the incident direction of the optical signal output from the transmitting laser diode 10 as shown in FIG. 8. At this time, the inclination angle of the splitter 30 with respect to the incident direction of the optical signal output from the transmitting laser diode 10 may be 30 to 60 °, but the transmission and reception of the input and output of the optical signal In order to have good efficiency, it is generally 45 °. The splitter 30 passes the optical signal output from the transmitting laser diode 10 to the optical fiber ferrule 20, and downwardly reflects the optical signal input to the optical fiber ferrule 20 through the optical fiber. It plays a role. At this time, the down-reflected optical signal is received by the receiving side photodiode 50 provided under the splitter 30.

The optical signal output from the transmitting side laser diode 10 is passed through the splitter 30. As shown in FIG. 8, not all of them pass through the splitter 30 due to the characteristics of the splitter 30. To be reflected. When the reflected light is present inside the module, a problem may occur that may be incident to the photodiode 50 of the receiving side. Therefore, the present invention does not pass through the splitter 30 and emits the reflected light to the outside of the module. It is characteristic.

To this end, it is provided with a reflector 40 so as not to pass through the splitter 30 so that upward light reflected by the splitter 30 is emitted to the outside of the module.

As shown in FIG. 8, the reflector 40 does not pass through the splitter 30 among the optical signals output from the transmitting laser diode 10 and emits light reflected by the splitter 30 to the outside of the module. Reflect as much as possible. In addition, the reflecting portion 41 of the reflecting portion 40 and the splitter 30 which do not pass through the splitter 30 and reflect the reflected light to be emitted to the outside of the module do not pass through the reflecting portion ( It is preferable that the angle J made by the light incident on the reflecting surface 41 of 40 is 10 to 50 degrees. The angle J between the reflection surface 41 of the reflection portion 40 and the light incident on the reflection surface 41 of the reflection portion 40 without passing through the splitter 30 is 10 to 50 °. When the light reflected by the reflective surface 41 can be directed to the outside of the module. If the angle formed by the light incident on the reflecting surface 41 of the reflector 40 without passing through the reflecting surface 41 of the reflector 40 and the splitter 30 is too small, the splitter 30 Since the area of the light reflected by the light becomes large, the area of the reflecting surface 41 of the reflector 40 should be widened, but the height of the optical module becomes high. If the light is too large, the light reflected by the splitter 30 is increased. Since the area of the reflector 40 may be reduced, the area of the reflecting surface 41 of the reflector 40 may be reduced, but the problem that the length of the optical module becomes longer occurs. Therefore, since it is disadvantageous in miniaturizing the optical module, it is preferable to have an appropriate angle.

At this time, the reflector 40 may be directly made of stainless steel or brass that does not rust, as well as a black epoxy treatment as well as a separate post treatment such as black coating or plating.

In addition, the module is preferably further provided with a window 60 for passing the light to be emitted to the portion reflected by the reflector 40 to be emitted to the outside of the module and maintains the airtightness of the module. In addition, the window 60 is coated with anti-reflection (AR) to prevent the reflection of the light reflected by the reflector 40 is reflected back into the module by the window 60. It is preferable. The antireflective coating of the window 60 is coated on both sides in the wavelength band of 1260 nm to 1650 nm depending on the wavelength of the transmitting optical signal generated by the transmitting side laser diode 10 to be used.

When the window 60 is an antireflective coating, most of the light reflected by the reflector 40 to the window 60 can be emitted to the outside of the module.

The receiving side photodiode 50 is installed under the splitter 30, and is input to the optical fiber ferrule 20 through an optical fiber to receive an optical signal reflected downward by the splitter 30.

An optical signal input to the receiving photodiode 50 to the optical fiber ferrule 20 through the optical fiber and reflected downward by the splitter 30 should be input, but light from the transmitting laser diode 10 as shown in FIG. 4. Reflection may start on the surface of the optical fiber ferrule polishing surface F and be reflected back by the splitter 30 to be incident on the receiving side photodiode 50. In order to reduce the amount of incident light, the optical fiber ferrule polishing surface F is generally subjected to an antireflection coating. The present invention is a predetermined angle to reduce the amount of light that is reflected by the optical fiber ferrule polishing surface (F) to the splitter 30 by the optical fiber ferrule polishing surface (F) and incident on the receiving side photodiode (50) (K: 78 ° to 85 °) the optical fiber ferrule polishing surface 21 polished to the existing direction (in Fig. 4, the ferrule polishing surface is positioned at the same angle as the direction of incidence of the optical signal output from the transmitting end into the optical fiber ferrule) Unlike this, the angle L formed in the left or right direction with respect to the incident direction of the output optical signal to the optical fiber ferrule 20 is 2 to 6 ° (see FIG. 9). When the polishing surface of the optical fiber ferrule 20 forms a predetermined angle L in the left or right direction with respect to the direction of incidence of the output optical signal into the optical fiber ferrule 20, the polishing surface 21 of the optical fiber ferrule 20 is formed. The light reflected by the ferrule polishing surface 21 by turning the direction of the wire and bending the ferrule itself is different from FIG. 4 and is different from FIG. 4 and FIG. 9 and FIG. 10 (output from the transmitting laser diode 10, passes through the splitter 30, and the optical fiber. The light signal reflected by the polishing surface 21 is indicated by a solid line, and the light reflected by the splitter 30 through the optical fiber 1 and the optical fiber ferrule 20 is incident to the receiving side photodiode 50 as a downward signal. As shown in the dotted line), the signal is directed outwards rather than toward the center of the receiving photodiode 50, thereby effectively reducing the amount of incident light to the receiving photodiode 50, and thus transmitting laser diode. At 10 By preventing the occurrence of noise due to the output optical signal to prevent the decrease in the reception sensitivity, it is possible to prevent the increase in raw material costs because there is no need to apply an anti-reflection (AR) coating on the ferrule surface.

The reason for bending the optical fiber ferrule 20 is as follows. When the light is emitted from the optical fiber ferrule polishing surface 21 to the optical fiber or vice versa, the light is bent in accordance with the Snell's law due to the difference in refractive index with air. The upstream light of the transmitting end should be incident to the optical fiber in a straight line with this angle of bending to maximize the coupling efficiency. In addition, when the optical fiber ferrule 20 does not bend, the receiving side of the optical fiber ferrule 20 when the optical fiber ferrule 20 does not bend because the angle of bending of the optical fiber ferrule 20 itself is added to the polishing angle K. The light re-incident to the photodiode 50 may be deflected more outwardly from the center of the receiving end. In addition, the downward light is emitted horizontally when it is emitted from the optical fiber ferrule 20, the polishing surface 21 is reflected by the 45 ° splitter 30 is vertically directed to the center of the receiving photodiode 50 to achieve the best coupling. You can do it.

The present invention further includes a lens 70 which focuses an optical signal and transmits the optical signal to the receiving side photodiode 50, and an isolator 80 which blocks an input optical signal from being transmitted to the transmitting laser diode 10. It is desirable to be.

The lens 70 is installed between the splitter 30 and the receiving side photodiode 50 to focus an optical signal reflected downward by the splitter 30 to transmit the optical signal to the receiving side photodiode 50. It plays a role of improving reception sensitivity.

The isolator 80 is inputted to the optical fiber ferrule 20 through the optical fiber and is not reflected downward by the splitter 30 and blocks the light passing through the splitter 30 from being transmitted to the transmitting laser diode 10. In this way, the transmitting side laser diode 10 is not influenced by external noise to enable smooth communication. An isolator is a device used for the transmission of microwaves or light waves, and is known to have a function capable of transmitting electromagnetic waves in one direction of the transmission line but not in the opposite direction.

Although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the above-described embodiments, and the present invention is not limited to the above-described embodiments without departing from the spirit of the present invention as claimed in the claims. Various modifications can be made by those skilled in the art, and such modifications are intended to fall within the scope of the appended claims.

1 is a diagram illustrating a structure of a general bi-directional (BIDI) optical transmission / reception module using two wavelengths for uplink transmission and downlink reception.

2 is a view showing an example used for communication using the bidirectional optical transmission and reception module of FIG.

3 is a view showing the principle of the optical module using a splitter (Splitter) for transmitting and reflecting by dividing the light of a specific wavelength by a certain ratio.

4 is a diagram illustrating a practical example of a bidirectional optical transmission / reception module using the optical module to which the splitter shown in FIG. 3 is applied.

Figure 5 is a perspective view showing the appearance of the bidirectional optical transmission module according to the present invention.

6 is a plan view of the bidirectional optical transmission module according to the present invention.

7 is a front view of the bidirectional optical transmission module according to the present invention.

8 is a cross-sectional view taken along the line A-A of FIG.

9 is a cross-sectional view taken along line B-B in FIG. 5.

10 is a cross-sectional view taken along the line C-C of FIG.

DESCRIPTION OF REFERENCE NUMERALS

10: transmitting side laser diode

20: fiber optic ferrule

21: polishing surface

30: splitter

40: reflector

41: reflective surface

50: receiving side photodiode

60: Windows

70: lens

80: isolator

Claims (5)

In the single wavelength bidirectional optical transmission module, A transmission side laser diode 10 for outputting an optical signal; An optical fiber ferrule (20) installed in front of the transmitting side laser diode (10) and having one side disposed in front of the transmitting side laser diode (10) and the other side connected to the optical fiber to input and output an optical signal; Between the optical fiber ferrule 20 and the transmitting laser diode 10 is installed to be inclined at an angle up and down with respect to the incident direction of the optical signal output from the transmitting laser diode 10 and the transmitting laser diode 10 A splitter 30 configured to pass an optical signal output from the optical fiber ferrule 20 to reflect the optical signal input to the optical fiber ferrule 20 through the optical fiber; Reflecting surface inclined at a predetermined angle so as to reflect the light reflected by the splitter 30 to the outside of the module without passing through the splitter 30 among the optical signals output from the transmitting laser diode 10 ( A reflector 40 having a surface 41 formed thereon; A reception side photodiode (50) installed below the splitter (30) and input to an optical fiber ferrule (20) through an optical fiber to receive an optical signal reflected downward by the splitter (30); Single wavelength bidirectional optical transmission and reception module, characterized in that comprises a. The method of claim 1, The module is further characterized in that the window 60 is further provided to pass the light to be emitted to the part reflected by the reflector 40 to be emitted to the outside of the module and maintains the airtightness of the module Wavelength Bidirectional Optical Transceiver Module. The method of claim 2, The window 60 is a single wavelength bi-directional optical transmission and reception module, characterized in that the anti-reflective coating to prevent the reflection of the light reflected by the reflector 40 to the inside of the module is transmitted. The method of claim 1, The reflecting portion 40 does not pass through the splitter 30 and the reflecting surface 41 of the reflecting portion 40 reflecting the reflected light not to pass through the splitter 30 to be emitted to the outside of the module. Single wavelength bidirectional optical transmission and reception module, characterized in that the angle (J) of the light incident on the reflecting surface 41 of 10 to 50 °. The method of claim 1, The polishing surface 21, which is one end of the optical fiber ferrule 20, has an angle formed in the left or right direction with respect to the direction of incidence of the optical signal output by the transmitting laser diode 10 into the optical fiber ferrule 20 ( L) is 2 to 6 ° single wavelength bi-directional optical transmission module.

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