KR101686602B1 - Bi-directional optical module - Google Patents

Abstract

The present invention provides a light emitting device comprising: a receptacle including an optical fiber for inputting a first optical signal; An optical transmitter for outputting a second optical signal; A first optical filter that transmits the second optical signal and reflects the first optical signal; An optical receiver for receiving the first optical signal; Wherein the first opening is formed at the center of the bottom surface of the fixing groove, and the bottom surface is a stopper for controlling the insertion position of the receptacle, wherein the first opening is formed at a center of the bottom surface of the fixing groove, .

Description

Bi-directional optical module < RTI ID = 0.0 >

The present invention relates to an optical transceiver module used in an optical communication system.

Generally, an optical transmission / reception module refers to a module in which various optical communication functions are accommodated in one package and connected to an optical fiber. 2. Description of the Related Art In recent years, a bidirectional optical module in which an optical transmitter using a laser diode as a light source and an optical receiver using a photodiode as an optical receiver are modularized is widely used.

The bidirectional optical transceiver module is coupled to the case with an optical transmitter, an optical receiver, an optical filter, an optical fiber, and a receptacle housing the optical fiber. In general, the case is manufactured by lathe machining, so burrs (burrs on the machined surface) are generated during machining. Therefore, there is a problem that an additional processing time is required to remove it and the unit price is increased.

Generally, the receptacle is welded to the case using a laser (Nd-YAG Laser). However, since the laser (Nd-YAG laser) is expensive equipment, there is a problem that the equipment cost increases. In addition, there is a problem that the assembly time is relatively long because of welding using a laser.

The present invention provides a bidirectional optical communication module that is excellent in assembling property and reduces manufacturing cost.

The present invention provides a bidirectional optical communication module in which internal optical crosstalk is reduced.

A bidirectional optical T / R module according to one aspect of the present invention includes: a receptacle including an optical fiber for inputting a first optical signal; An optical transmitter for outputting a second optical signal; A first optical filter that transmits the second optical signal and reflects the first optical signal; An optical receiver for receiving the first optical signal; And a case including a first opening in which the receptacle is received, wherein the first opening is formed at the center of the bottom surface of the fixing groove, and the bottom surface functions as a stopper for controlling the insertion position of the receptacle .

In the bidirectional optical transceiver module according to one aspect of the present invention, the receptacle includes a rim formed along an outer circumferential surface, a cutout portion is formed in the rim portion, and a guide wall corresponding to the cutout portion is formed on a side wall of the bottom surface. Can be formed.

In the bidirectional optical T / R module according to an aspect of the present invention, a plurality of contact protrusions may be formed on the bottom surface.

In the bidirectional optical transceiver module according to one aspect of the present invention, the contact protrusion may be metal-bonded to the rim portion.

In the bidirectional optical transceiver module according to an aspect of the present invention, the case may be formed by Metal Injection molding (MIM).

In the bidirectional optical transceiver module according to one aspect of the present invention, the case may have a thermal expansion coefficient of 10.8 x 10 < ^-6 > / DEG C or less.

In the bidirectional optical transceiver module according to one aspect of the present invention, the case includes an inclined surface formed on an inner surface facing the optical receiver, and an input axis of the first optical signal input to the optical receiver is connected to the inclined surface at a first angle .

In the bidirectional optical transceiver module according to one aspect of the present invention, the first angle may be larger than a second angle between the input shaft and the first optical filter.

 In the bidirectional optical T / R module according to one aspect of the present invention, the inclined surface is inclined toward the output direction of the second optical signal output from the optical transmitter.

According to the present invention, the assembling property is improved, and the stub can be assembled to the case at an accurate position.

In addition, internal optical crosstalk can be lowered.

1 is a conceptual diagram of a bidirectional optical T / R module according to an embodiment of the present invention,
2 is an exploded perspective view of a receptacle according to an embodiment of the present invention,
3 is a perspective view of a case according to an embodiment of the present invention,
4 is a view for explaining a process of coupling a receptacle to a case according to an embodiment of the present invention,
Fig. 5 is an enlarged view of a portion A in Fig. 1,
6 is a conceptual view for explaining a path of a current during resistance welding,
Fig. 7 is an enlarged view of a portion B in Fig. 1,
8 is a conceptual diagram for explaining a configuration for preventing light outputted from an optical transmitter from being reflected and input to an optical receiver according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the present invention, the terms "comprising" or "having ", and the like, specify that the presence of a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

It is to be understood that the drawings are to be construed as illustrative and not restrictive.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant description thereof will be omitted.

FIG. 1 is a conceptual diagram of a bidirectional optical T / R module according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of a receptacle according to an embodiment of the present invention.

Referring to FIG. 1, an optical T / R module according to an embodiment of the present invention includes a case 100, a receptacle 200 including an optical fiber 211 for transmitting a first optical signal, An optical transmitter 300 for outputting a second optical signal to the optical fiber 211 and a first optical filter 510 disposed between the optical fiber 211 and the optical transmitter 300, .

The case 100 is formed with a plurality of openings into which the optical fiber 211, the optical transmitter 300, and the optical receiver 400 are inserted. The optical fiber 211 and the optical transmitter 300 are disposed to face each other in the case 100 and the optical receiver 400 may be disposed in a direction perpendicular to the direction in which the optical fiber 211 is inserted. However, the present invention is not limited thereto, and the optical transmitter 300 may be disposed in a direction perpendicular to the direction in which the optical fiber 211 is inserted.

The receptacle 200 is connected to an external connector and outputs a first optical signal output from the outside to the first optical filter 510. The receptacle 200 includes a holder 230 coupled to the case 100, a stub 210 fitted to the holder 230 and having an optical fiber 211 disposed therein, a sleeve 240 coupled to the stub 210, And a connector housing 250 coupled to the holder 230.

The ends of the optical fibers 211 may be disposed inside the case 100. The optical fiber 211 transmits the second optical signal output from the optical transmitter 300 to the external connector or outputs the first optical signal received from the outside to the first optical filter 510.

The optical transmitter 300 transmits the second optical signal to the outside through the optical fiber 211. The second optical signal has a wavelength different from that of the first optical signal output from the optical fiber 211. The optical transmitter 300 may be applied to all structures of a general TiO can including a light source 310, a header 320, and a lens 330.

The light source 310 is formed of a semiconductor light emitting element, converts an electrical signal into an optical signal, and outputs the optical signal. As the light source 310, a laser diode may be used. The laser diode is suitable as a light source for optical communication because it has a low power consumption and narrow spectrum and can collect light of high output finely.

The header 320 on which the light source 310 is mounted is formed in a disk shape, and a plurality of connection pins 340 are inserted through the header 320. The connection pin 340 forms an electrical path between the light source 310 and an external circuit board (not shown). For example, a positive (+) signal, a negative (-) signal, and a ground signal may be output to each connection pin 340.

The lens 330 transmits the optical signal output from the light source 310 to the optical fiber 211 side. The lens 330 may be disposed at an appropriate position to transmit the optical signal to the optical fiber 211 side.

The distance adjusting member 600 includes a first adjusting member 610 disposed on the other side of the case 100 and a second adjusting member 620 inserted and fixed to the first adjusting member 610. The distance by which the second optical signal emitted from the optical transmitter 300 reaches the optical fiber 211 is adjusted according to the degree of insertion of the second adjusting member 620 and the first adjusting member 610. Accordingly, the output of the optical transmitter 300 can be adjusted according to the degree of insertion of the second adjusting member 620 and the first adjusting member 610. The optical transmitter 300 is inserted and fixed to one side of the second adjusting member 620.

The first adjusting member 610 and the second adjusting member 620 are formed in an empty cylindrical shape and have different diameters. The second adjusting member 620 is inserted into the first adjusting member 610 at a proper position, and then fixed by welding or the like. Here, the proper position refers to a position adjusted to the required second optical signal output level.

The optical receiver 400 converts the optical signal received from the outside through the optical fiber 211 into an electrical signal. The optical receiver 400 may be a photodiode. When the optical signal is incident on the photodiode, a reverse current proportional to the incident light amount flows. That is, the optical receiver 400 can convert the optical signal into an electrical signal by changing the output current according to the amount of incident light.

The first optical filter 510 is an optical filter and may be disposed between the optical transmitter 300 and the optical fiber 211 to pass the optical signal transmitted from the optical transmitter 300, .

The first optical filter 510 can be designed to pass only optical signals of a specific wavelength. For example, the first optical filter 510 may pass the second optical signal transmitted from the optical transmitter 300, and may reflect the first optical signal received from the outside through the optical fiber 211.

The first optical filter 510 may be a 45-degree filter and may reflect an optical signal received from the outside through the optical fiber 211 in a direction perpendicular to the incident direction. When the wavelength interval between the first optical signal and the second optical signal is narrow, the first optical filter 510 may divide the optical output instead of splitting the wavelength. (Power split filter)

When the wavelength interval between the upstream signal and the downstream signal of the bidirectional optical transmission / reception module is within 40 to 60 nm, a power split filter can be used to separate the two wavelengths. A WDM filter selectively transmits and reflects wavelengths, but a power split filter transmits and reflects the intensity of the entire optical signal at a designed ratio irrespective of the wavelength.

The second optical filter 530 is an optical filter and passes only the first optical signal reflected by the first filter 510. The first optical signal having passed through the second filter 530 is input to the optical receiver 400 and converted into an electrical signal. In one example, the second optical filter 530 may be disposed on top of the first optical filter to pass a first optical signal that is vertically reflected by the first optical filter 510, .

The isolator 520 blocks the optical signal reflected and received by the optical fiber 211 or an optical component included in the optical module. The isolator 520 may include a polarizer for passing only an optical signal having a predetermined polarization component, an analyzer, and a Faraday rotator for rotating the optical signal input thereto by 45 degrees in linear polarization.

2, the receptacle 200 includes a holder 230 coupled to the case, a stub 210 fitted in the holder 230 and having an optical fiber disposed therein, a sleeve 240 coupled to the stub 210, And a connector housing 250 coupled to the holder 230.

The holder 230 is formed with a rim 233 protruding from the outer circumferential surface. A cutout portion 233a is formed in the rim portion 233a. The holder 230 may have an isolator receiving portion 262 at the end thereof, and a first optical filter disposing surface.

The stub 210 has an optical fiber disposed therein. A space for receiving the external connector is formed in the interior of the sleeve 240 and the connector housing 250. Specifically, the sleeve 240 is formed with a slit 241 in the longitudinal direction to press-fit the ferrule of the inserted external connector. With this structure, the external connector is freely detachable.

FIG. 3 is a perspective view of a case according to an embodiment of the present invention, and FIG. 4 is a view illustrating a process of coupling a receptacle to a case according to an embodiment of the present invention.

3, the case 100 has a substantially rectangular parallelepiped shape. The case 100 has a first opening 110 formed at one side thereof for receiving the receptacle, a second opening formed at the other side for receiving the optical transmitter, And a third opening 120 in which the first opening 120 is received.

The case 100 can be manufactured by Metal Injection molding (MIM). Metal injection molding is a method in which a metal powder is put into a mold and pressurized, which is advantageous for forming a sophisticated shape compared to a lathe.

At one side of the case 100, a fixing groove 111 is formed. A first opening 110 is formed at the center of the bottom surface 113 of the fixing groove 111. The bottom surface 113 functions as a stopper for adjusting the insertion position of the receptacle.

A guide wall 112 having a flat surface is formed on the side wall of the fixing groove 111 to guide the cutout portion 233a formed at the rim of the receptacle.

4, the guide wall 112 is formed in a shape corresponding to the cutout portion 233a, so that the receptacle is guided by the guide wall 112 and is coupled to the case 100 at the correct position.

In general, the bidirectional optical transceiver module is affected by the transmission / reception (Tx / Rx) characteristics depending on the direction of assembly of the stub. Therefore, according to the present invention, the stub can be assembled in a predetermined direction by the guide wall 112, and the optical coupling efficiency is improved. Particularly, it is effective when the ferrule of the external connector and the stub of the receptacle 200 are of an APC type (Angled Physical Contact) having an inclined surface contacted with each other.

A plurality of contact protrusions 114 are formed on the bottom surface 113. 5, the contact protrusion 114 is metal-joined with the rim portion 233 of the holder 230 to fix the receptacle 200 to the case 100. As shown in FIG. For example, the contact protrusion 114 and the rim portion 233 can be electrically welded. Therefore, it is advantageous in that the manufacturing cost is reduced and the welding speed is faster than that of the laser welding machine because the electric welding machine is used at a lower cost than the conventional laser welding machine.

Referring to FIGS. 3 and 6, the contact protrusions 114 may be disposed at intervals of 60 degrees along the first openings 110 to balance the amount of current per unit time flowing through the contact protrusions during resistance welding.

That is, the angle formed by the imaginary line extending from the center of the first opening 110 to each contact protrusion 114 may be arranged to be 60 degrees. At this time, each of the contact protrusions 114 may have a pair of sub-protrusions.

The first imaginary line L1 extending in the thickness direction of the contact protrusion 114a closest to the third opening 120 intersects the second imaginary line L2 extending the center of the third opening 120, .

If the first imaginary line L1 intersects with the second imaginary line L2, there is a problem that the path PL of the current which is conductive by the diameter of the third opening 120 during resistance welding becomes long. Therefore, in order to shorten the path PL of the conduction current, it is preferable that the first imaginary line L1 is arranged so as not to intersect at least the center of the second opening 120. [

The conventional case is manufactured by lathe machining, and it is difficult to process the shape of the guide wall and the elaborate shape such as contact protrusions, and there is a problem that a burr is generated and a process for removing it is required.

However, since the case of the present invention is manufactured by metal injection molding, a burr is not generated and a process of removing a burr can be omitted, and a guide wall and a contact protrusion can be easily manufactured.

Table 1 below is a table in which a plurality of metal cases are manufactured with different composition ratios. Each composition has a value greater than zero and is expressed in weight percent. The remainder is Fe and unavoidable impurities. Table 2 is a table measuring the thermal expansion coefficient (CTE), thermal conductivity, and the amount of change according to the temperature according to the material of the case.

C Si Mn P S Ni Cr Mo Other Example 1 0.03 1.0 2.0 0.045 0.03 9.0 to 13.0 18.0 to 20.0 - - Example 2 0.03 1.0 2.0 0.045 0.03 9.0 to 13.0 18.0 to 20.0 2.0 to 3.0 Example 3 0.12 0.75 1.0 0.040 0.03 0.60 16.0 to 18.0 - - Example 4 0.07 1.00 1.0 0.040 0.03 3.0 to 5.0 15.0 to 17.5 - Cu: 3.0 to 5.0
Nb: 0.15-0.45

CTE
(0 ° C to 100 ° C) Thermal Conductivity
(at < RTI ID = 0.0 & Variation
(占 퐉, when the temperature is changed from 20 占 폚 to 85 占 폚) Example 1 16.9 x 0 ^-6 / C 16.2 (W / m.k) 76.9 Example 2 16.0 x 0 ^-6 / C 16.2 (W / m.k) 72.8 Example 3 10.4 x 0 ^-6 / C 23.9 (W / m.k) 47.3 Example 4 10.8 × 0 ^-6 / ° C 17.0 (W / m.K) 49.1

Referring to Table 1, the first through fourth experimental examples are materials capable of laser welding, but in the first experimental example and the second experimental example, a CTE value is large and a tracking error occurs, There is a problem.

On the other hand, the third and fourth experimental examples have an advantage that the tracking error can be reduced because the CTE value is low and the amount of change at the time of high-temperature exposure is small. Therefore, it is preferable that the case of the present invention has a coefficient of thermal expansion of 10.8 x 10 < ^-6 > / DEG C or less and a variation of 50 mu m or less when the temperature is changed from 20 DEG C to 85 DEG C.

At this time, in the third experimental example, rust may be generated by the brine. However, in the fourth experimental example, the CTE value is similar to that of the third experimental example, thereby improving the tracking error and also being advantageous against salt water.

FIG. 7 is an enlarged view of a portion B in FIG. 2, and FIG. 8 is a conceptual diagram illustrating a configuration for preventing light output from an optical transmitter from being reflected by an optical receiver according to an embodiment of the present invention.

Referring to FIGS. 7 and 8, the case 100 is formed with an inclined surface 101a on a surface facing the optical receiver 400. FIG. The inclined surface 101a may be a side surface of the groove 101 formed on the surface facing the optical receiver 400. [ The inclined surface 101a may be inclined toward the output direction of the optical signal output from the optical transmitter.

The slope surface 101a prevents the light L2 reflected by the first optical filter 510 from being input to the optical receiver 400 from among the second optical signals output from the optical transmitter.

The conventional structure has a problem that the surface facing the optical receiver is formed as a flat surface and the light L2 reflected by the first optical filter 510 is vertically reflected and input to the optical receiver. At this time, reception error (Rx Error) occurs due to internal optical crosstalk generated by reflection of light in the case.

Most of the light output from the optical transmitter 300 is transmitted to the outside through the first optical filter 510 but some light L2 is incident on the low reflection layer 512 of the first optical filter 510 And can be reflected by the high reflection layer 511. However, since the reflected light L2 is not reflected to the light receiver 400 side by the inclined surface 101a, the noise of the light receiver 400 is reduced. Light L2 reflected by the inclined surface 101a can be reflected or absorbed inside the case.

Specifically, the first angle? 1 formed by the input axis P of the first optical signal input to the optical receiver and the inclined surface 101a may be 10 degrees to 70 degrees. The first angle? 1 may be larger than the second angle? 2 between the input shaft P and the first optical filter 510. In this case, the light reflected by the first optical filter 510 is not reflected to the optical receiver side.

100: Case
110: first opening
111: Fixing groove
112: guide wall
113: bottom surface
200: Receptacle
230: holder
233:
233a: cutout portion
300: optical transmitter
400: Optical receiver

Claims (10)

A receptacle including an optical fiber for inputting a first optical signal;
An optical transmitter for outputting a second optical signal;
A first optical filter that transmits the second optical signal and reflects the first optical signal;
An optical receiver for receiving the first optical signal;
And a case including a first opening through which the receptacle is received,
Wherein the first opening is formed at the center of the bottom surface of the fixing groove and the bottom surface is a stopper for controlling the insertion position of the receptacle,
The case is C, Si, Mn, F, S, Ni, and Cr, and the thermal expansion coefficient of 10.8 × 10 ^-6 / ℃ than bi-directional optical transceiver module.
The method according to claim 1,
The receptacle includes a rim formed along an outer circumferential surface, a cutout portion is formed in the rim,
And a guide wall corresponding to the cutout portion is formed on a side wall of the bottom surface.
3. The method of claim 2,
And a plurality of contact protrusions are formed on the bottom surface.
The method of claim 3,
Wherein the contact protrusion is metallically coupled to the rim.
The method according to claim 1,
The case is formed by metal injection molding (MIM).
delete The method according to claim 1,
Wherein the case includes an inclined surface formed on an inner surface facing the optical receiver,
Wherein an input axis of the first optical signal input to the optical receiver has a first angle with the inclined plane.
8. The method of claim 7,
Wherein the first angle is greater than a second angle between the input shaft and the first optical filter.
8. The method of claim 7,
Wherein the inclined surface is inclined toward an output direction of a second optical signal output from the optical transmitter.
The method of claim 3,
The case including a third aperture in which the optical receiver is received,
Wherein the first imaginary line extending in the thickness direction closest to the third opening does not intersect the second imaginary line extending the center of the third opening.

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