WO2003098304A1

WO2003098304A1 - Plug-in type optical module

Info

Publication number: WO2003098304A1
Application number: PCT/KR2003/000931
Authority: WO
Inventors: Ki Chul Shin
Original assignee: Iljin Corporation
Priority date: 2002-05-17
Filing date: 2003-05-12
Publication date: 2003-11-27
Also published as: AU2003235204A1; KR20030089280A; KR100474105B1

Abstract

Disclosed is an optical module in which there is provided a socket having contact points for electrically connecting internal active elements to an external circuit board formed at both terminals of the socket, and a matching circuit for achieving impedance matching with the active elements formed between the contact points, and the contact points to be connected to the external circuit board is horizontally protruded from one surface of the package. The optical module is easily attached to and detached from an optical communication system, and has high frequency characteristics so that a signal loss and interference between signals are minimized.

Description

PLUG-IN TYPE OPTICAL MODULE

Technical Field

The present invention relates to a plug-in type optical module, and more particularly to an optical module comprising a socket provided with matching circuit for providing electrical contact points between an external circuit board and internal active elements and achieving impedance matching with the active element between the both contact points, in which the contact points to be connected to the external circuit board is protruded from a rear surface of a package in parallel with an optical axis .

Background Art

In the course of progress of the information age, there have been required optical modules, which can transmit a large quantity of information. Such optical modules must have excellent quality themselves and also high reliability for maintaining their excellent quality for a long period of time. In order to promote the spread of the optical modules for achieving a FTTH (fiber to the home) system, the optical modules should be manufactured at low cost. Particularly, since the capacity of an optical transmitting system is recently increased, the size of an optical module mounted on the optical transmitting system has been reduced so that the number of the optical modules mounted per unit area is increased.

Generally, methods for aligning an optical fiber and active elements (for example, a laser diode and a photo diode) of an optical module for converting an electrical signal into an optical signal or an optical signal into an electrical signal are divided into two types, i.e., an active alignment method and a passive alignment method. In case of the active alignment method, an apparatus with resolution of less than _/-on unit is used for aligning the active elements and the optical fiber. This apparatus finely moves to find the precise positions of the active elements and the optical fiber of the optical module in which an optical output is maximum. It takes a long time to use the apparatus in this method, thereby reducing mass production. Furthermore, additional components are required to perform the active alignment method, thus increasing the production cost of the optical module. In case of the passive alignment method, the active elements and the optical fiber are precisely aligned under the condition that current is not applied to the active elements . The maximum optical output is obtained only when the position of the optical fiber and the active elements are precisely aligned before the optical fiber is substantially aligned.

Since the recent optical modules are manufactured by the active alignment method using an expensive apparatus, which can finely control the alignment in the optical fiber alignment step, it takes a long time to manufacture the optical modules, thereby increasing the cost of the modules and reducing the productivity of the modules .

As shown in Fig. 1, in a conventional TO-can package 10, pins 11 are aligned in parallel with an optical axis. In order to connect an active element in the TO-can package 10 to a circuit board 12 to operate the active element, the pins 11 should be bent and then fixed to the circuit board 12. This manner of fixing the bent pins 11 to the circuit board 12 causes problems such as interference of signals between the pins 11. Further, in this case, it is very difficult to adjust the length of the pins 11 so as to fit into impedance matching, thus causing difficulty in operating the active element at high speeds more than 2.5 Gbps . As shown in Fig. 2, in a mini- DIL package 20, pins attached to the external surface of the package 20 are arranged to be vertical to an optical axis. In order to mount the mini-DIL package 20 on a small formed package 22, the mini-DIL package 20 must be turned at an angle of 90° and then mounted on a circuit board 23. Further, the circuit board 23 must be also turned at an angle of 90° relative to the direction of a module and then mounted on the module. Accordingly, the use of the mini-DIL package 20 for manufacturing a module causes complexity and difficulty in a process for manufacturing the module. This manner of fixing the pins to the circuit board 23 causes problems such as interference of signals between the pins. Further, in this case, it is very difficult to adjust the length of the pins so as to fit into impedance matching, thus causing difficulty in operating the active element at high speeds more than 2.5 Gbps .

Disclosure of the Invention

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide an optical module, which is easily attached to and detached from an optical communication system and has high frequency characteristics so that a signal loss and interference between signals are minimized.

It is another object of the present invention to provide an optical module, in which a passive alignment is obtained by aligning a substrate and a package in advance without operating active elements . In accordance with one aspect of the present invention, the above and other objects can be accomplished by the provision of an optical transmitting module comprising a substrate provided with active elements attached thereto at designated positions, and a package provided with light collection means for transferring light emitted from a light emitting element to an optical fiber, and electrical contact points located between the active elements and an external circuit board, wherein the package comprises a socket having contact points for electrically connecting the active elements to the external circuit board formed at both terminals of the socket, and a matching circuit for achieving impedance matching with the active elements formed between the contact points, the contact points to be connected to the external circuit board being horizontally protruded from one surface of the package .

Preferably, a protuberance with a designated shape may be formed on either one of a bottom surface of the substrate and a bottom surface of a cavity formed in the package, and a concavity corresponding the protuberance may be formed in the other one so that a passive alignment is achieved by coupling the protuberance to the concavity.

In accordance with another aspect of the present invention, there is provided optical receiving module comprising a substrate provided with a light receiving element attached thereto at a designated position, and a package provided with light collection means for transferring light from an optical fiber to the light receiving element, and electrical contact points located between the light receiving element and an external circuit board, wherein the package comprises a socket having contact points for electrically connecting the light receiving element to the external circuit board formed at both terminals of the socket, and a matching circuit for achieving impedance matching with the light receiving element formed between the contact points, the contact points to be connected to the external circuit board being horizontally protruded from one surface of the package . Preferably, a protuberance with a designated shape may be formed on either one of a bottom surface of the substrate and a bottom surface of a cavity formed in the package, and a concavity corresponding the protuberance may be formed in the other one so that a passive alignment is achieved by coupling the protuberance to the concavity. In accordance with still another aspect of the present invention, there is provided an optical transreceiving module integrally comprising an optical transmitting module and an optical receiving module. Brief Description of the Drawings

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a perspective view of a conventional TO- can package;

Fig. 2 is a perspective view of a conventional mini- DIL package; Fig. 3 is a cross-sectional view of an optical transmitting module in accordance with the present invention;

Fig. 4a is a plan view of a transmitting substrate provided with active elements attached thereto; Fig. 4b is a perspective view of the transmitting substrate provided with active elements attached thereto;

Fig. 4c is a bottom view of the transmitting substrate provided with active elements attached thereto;

Fig. 5 is an exploded perspective view of an optical transmitting module in accordance with the present invention;

Fig. 6 is a cross-sectional view of an optical receiving module ^'in accordance with the present invention; Fig. 7a is a front view of a receiving substrate provided with a light receiving element attached thereto; Fig. 7b is a perspective view of the receiving substrate provided with a light receiving element attached thereto;

Fig. 7c is a bottom view of the receiving substrate provided with a light receiving element attached thereto;

Fig. 8 is an exploded perspective view of an optical receiving module in accordance with the present invention; and

Fig. 9 is an exploded perspective view of an optical transreceiving module in accordance with the present invention.

Best Mode for Carrying Out the Invention Now, preferred embodiments of the present invention will be described in detail with reference to the annexed drawings .

As shown in Figs. 3 to 5 , in accordance with one preferred embodiment of the present invention, an optical transmitting module 100 comprises a package 115 for an integrated module, a substrate 101, a light emitting element 103, and a light receiving element 104. The package 115 is provided with a light collection means formed on the front surface of the package 115, and a plurality of pins 124 horizontally protruded from the rear surface of the package 115 and arranged in at least two lines. The substrate 101 is attached to the bottom surface of a cavity formed in the package 115. The light emitting element 103 is mounted on the upper surface of the substrate 101. The light receiving element 104 serves as a sensor for controlling the optical output from the light emitting element 103.

The light collection means of this embodiment includes a lens insertion hole 122 formed in the front surface of the package 115, a transmitting lens 116, and a transmitting guide pipe 118 connected to the lens insertion hole 122 and provided with a hollow 118a for receiving a transmitting ferrule 112.

It is not necessary that the position of the light collection means should be limited to the front surface of the package 115. In case the light emitting surface of the light emitting element 103 is perpendicular to the bottom surface of the package 115, the light collection means should be positioned on the upper surface of the package 115. Accordingly, it is noted that the position of the light collection means on the package 115 is changeable depending on the location of the light emitting surface of the light emitting element 103.

Generally, a ball lens is used as the transmitting lens 116. The transmitting lens 116 is fixedly installed in the lens insertion hole 122 at a position calculated in advance so that light emitted from the light emitting element 103 is concentrated on a core of an optical fiber 111.

The transmitting guide pipe 118 is provided with the hollow 118a for receiving the transmitting ferrule 112 including the optical fiber 111 installed therein. The ferrule 112 is not limited in terms of its shape. However, preferably, the ferrule 112 is .formed to have a cylindrical shape. In this case, an inner diameter 118b of the hollow 118a substantially coincides with an outer diameter of the ferrule 112. Accordingly, even if the ferrule 112 is inserted into the hollow 118a in any direction, the light emitted from the light emitting element 103 is precisely concentrated on the core of the optical fiber 111. The package 115 is not limited in terms of its material. Generally, the package 115 may be made of materials such as ceramic, metal (including alloy) , resin, or their equivalents. Preferably, a protuberance 120 having a designated shape is formed on the bottom surface of the cavity of the package 115 so as to fix the substrate 101, and an opening for receiving the substrate 101 and a cover 126 are provided on the upper surface of the package 115. Here, the position of the opening is not limited, but is changeable depending on the position of the light collection means. The protuberance 120 formed on the bottom surface of the cavity of the package 115 serves as means for precisely fixing the substrate 101 at a height determined in advance so that the light emitted from the light emitting element 103 at the optimum position is incident on the transmitting lens 116. The protuberance 120 is not limited in terms of its shape. Accordingly, the protuberance 120 may be formed to have a shape of a V-groove or a MESA structure provided with a side wall slanted at a designated angle so that the substrate 101 is easily attached to the protuberance 120.

A socket 124 is integrally attached to one surface of the package 115. Contact points C and C are formed on both terminals of the socket 124 so that the contact points C are electrically connected to the internal active elements 103 and 104 and the contact points C are electrically connected to an external circuit board 125. A matching circuit 129 for achieving impedance matching with the active elements 103 and 104 is located between the contact points C and C . The contact points C to be connected to the external circuit board 125 are horizontally protruded from one surface of the package 115 so that the contact points C are easily connected to the external circuit board 125.

The contact points C and C , and the matching circuit 129 may be formed on the upper or lower surface of the inside of the socket 124, or both the upper and lower surfaces of the inside of the socket 124.

The matching circuit 129 may be formed on a substrate 128 with a designated dielectric constant (here, a non- described reference number 128' representing an insulating plate) . Preferably, a protection circuit for minimizing signal interference may be formed together with the matching circuit 129 on the substrate 128. The detailed constitution of the matching circuit 129 may be selected from various types by those skilled in the art according to required characteristics (for example, the constitution of the matching circuit 129 may be determined by the dielectric constant of the substrate 128) , but does not constitute the subject matter of the present invention. Of course, the matching circuit 129 and/or the protection circuit may have a multi-layered structure. This structure minimizes a signal loss and interference between signals, thus allowing the optical module to be used as an element, which is operable at high speeds more than 2.5 Gbps .

Preferably, the substrate 101 is a semiconductor substrate, for example, made of a silicon material. The light emitting element 103 is attached, using solder

105, to the front area of the upper surface 101a of the substrate 101 at a constant height determined in advance so that the light is optimally incident on the transmitting lens 116. The light receiving element 104 for sensing the strength of the light irradiated from the rear surface of the light emitting element 103 is attached, using the solder 105, to the rear area of the upper surface 101a of the substrate 101. A light reflective groove 102 with a designated shape is formed in the substrate 101 under the light receiving element 104. The light reflective groove 102 serves to reflect the light irradiated from the rear surface of the light emitting element 103 and then to allow the reflected light to be incident on the surface of the light receiving element 104. Preferably, the light reflective groove 102 is a V-shaped groove with a certain width and a thickness, which are determined by the orientation of crystals of the substrate 101. However, the shape of the light reflective groove 102 is not limited thereto.

The light emitting element 103 and the light receiving element 104 are not limited to the above- described positions. For example, the light emitting element 103 may be stacked on the light receiving element 104 so that a part of the light emitted from the light emitting element 103 is reflected and then the reflected light is incident on the upper surface of the light receiving element 104.

Contact areas 132 and 133 and patterns are provided on the substrate 101 at designated positions so that the light emitting element 103 and the light receiving element 104 are electrically connected to the pins 124 providing the connection to the external circuit board (not shown) .

A laser diode is generally used as the light emitting element 103. Preferably, an uneven structure (not shown) with a height and a size designated in advance by the orientation determined by the crystalline characteristics of single crystals may be formed on the bottom surface of the laser diode. In this case, another uneven structure with a height and a size designated in advance is formed at a constant position on the substrate 101 to which the light emitting element 103 is attached so that the uneven structure of the substrate 101 is engaged with the uneven structure of the laser diode, thereby allowing the light emitting element 103 to be mounted at a precise position on the substrate 101 without performing any alignment procedure.

A photo diode is generally used as the light receiving element 104 for a monitor. The light receiving element 104 serves to control the strength of the light irradiated from the front surface of the light emitting element 103 by sensing the strength of the light incident on the surface of the light receiving element 104. A control circuit for controlling the light receiving element 104 may be formed on an external electronic circuit board (not shown) , and detailed description thereof will thus be omitted because it is considered to be obvious to those skilled in the art .

A concavity 106 is formed in the bottom surface 101b of the substrate 101 so that a shape and a size of the concavity 106 correspond to those of the protuberance 120 formed on the bottom surface of the cavity of the package 115. The concavity 106 is not limited in terms of its forming method, but may be formed by any conventionally known etching method.

The passive alignment is simply achieved by coupling the concavity 106 of the substrate 101 with the protuberance 120 of the package 115. That is, since the final position of the light emitting element 103 is obtained by a method controlled in advance so that an optical axis is concentrated on the core of the optical fiber 111 in the ferrule 112, the passive alignment can be simply achieved by a single step for fixedly inserting the ferrule 112 into the package 115.

Also, the present invention also relates to a multi- optical transmitting module comprising at least two optical transmitting modules aligned in parallel and then packaged. Hereinafter, an optical receiving module in accordance with another preferred embodiment of the present invention will be described in detail with reference to Figs . 6 to 8. As shown in Figs . 6 to 8 , in accordance with another preferred embodiment of the present invention, an optical receiving module 200 comprises a package 115' for an integrated module, a substrate 107, and a light receiving element 108. The package 115' is provided with a light collection means formed on the front surface of the package 115' . The substrate 107 is attached to the bottom surface of a cavity formed in the package 115' . The light receiving element 108 is mounted on the front surface of the substrate 107. The light collection means of this embodiment includes a lens insertion hole 123 formed in the front surface of the package 115', a receiving lens 117, and a receiving guide pipe 119 connected to the lens insertion hole 123 and provided with a hollow 119a for receiving a receiving ferrule 114.

In the same manner as the above light transmitting module 100, it is not necessary that the position of the light collection means should be limited to the front surface of the package 115' . Generally, a ball lens is used as the receiving lens 117. The receiving lens 117 is fixedly installed in the lens insertion hole 123 at a position calculated in advance so that light emitted from an optical fiber 113 is concentrated on an acceptance core of the light receiving element 108.

The receiving guide pipe 119 is provided with the hollow 119a for receiving the receiving ferrule 114 including the optical fiber 113 installed therein. The ferrule 114 is not limited in terms of its shape. However, preferably, the ferrule 114 is formed to have a cylindrical shape. In this case, an inner diameter 119b of the hollow 119a substantially coincides with an outer diameter of the ferrule 114. Accordingly, even if the ferrule 114 is inserted into the hollow 119a in any direction, the light is precisely concentrated on the acceptance core of the light receiving element 108.

A protuberance 121 having a designated shape is formed on the bottom surface of the cavity of the package 115' so as to fix the substrate 107, and an opening for receiving the substrate 107 and a cover 126' are provided on the upper surface of the package 115' . Here, in the same manner as the above light transmitting module 100, the position of the opening in the optical receiving module 200 is not limited, but is changeable depending on the position of the light collection means. The protuberance 121 formed on the bottom surface of the cavity of the package 115' serves as means for precisely fixing the substrate 107 at a height determined in advance so that the light emitted from the optical fiber 113 is concentrated on the acceptance core of the receiving lens 117. The protuberance 121 is not limited in terms of its shape. Accordingly, the protuberance 121 may be formed to have a shape of a V-groove or a MESA structure provided with a side wall slanted at a designated angle so that the substrate 107 is easily attached to the protuberance 121.

A socket 124' is integrally attached to one surface of the package 115' . Contact points C and C' are formed on both terminals of the socket 124' so that the contact points C are electrically connected to the internal light receiving element 108 and the contact points C are electrically connected to an external circuit board. A matching circuit for achieving impedance matching with the light receiving element 108 is located between both the contact points C and C . The contact points C to be connected to the external circuit board are horizontally protruded from one surface of the package 115' so that the contact points C are easily connected to the external circuit board.

The contact points C and C and the matching circuit may be formed on the upper or lower surface of the inside of the socket 124', or both the upper and lower surfaces of the inside of the socket 124' .

The matching circuit may be formed on a substrate with a designated dielectric constant. Preferably, a protection circuit for minimizing signal interference may be formed together with the matching circuit on the substrate. The detailed constitution of the matching circuit may be selected from various types by those skilled in the art according to required characteristics (for example, the constitution of the matching circuit may be determined by the dielectric constant of the used substrate), but does not constitute the subject matter of the present invention.

Of course, the matching circuit and/or the protection circuit may have a multi-layered structure. This structure minimizes a signal loss and interference between signals, thus allowing the optical module to be used as an element, which is operable at high speeds more than 2.5 Gbps .

The substrate 107 is not limited in terms of its material, but may be made of a ceramic material. The light receiving element 108 is attached to the front surface 107a of the substrate 107 by solder 109, and a contact area 134 is provided on the substrate 107 at a designated position so that the contact area 134 is electrically connected to the contact point C of the socket 124. A photo diode is preferably used as the light receiving element 108. The light receiving element 108 is fixedly located at a designated position on the substrate 107 so that the light receiving element 108 and a central axis of the receiving lens 117 are arranged in a straight line .

A concavity 110 is formed in the bottom surface 107b of the substrate 107 so that a shape and a size of the concavity 110 correspond to those of the protuberance 121 formed on the bottom surface of the cavity of the package 115' . The concavity 110 is not limited in terms of its forming method, but may be formed by means of a mold in manufacturing the substrate 107 or by a separate cutting step. The passive alignment is simply achieved by coupling the concavity 110 of the substrate 107 with the protuberance 121 of the package 115'. That is, since the light receiving element 108 is fixed to the front surface of the substrate 107 by a method controlled in advance so that the light emitted from the optical fiber 113 is concentrated on the acceptance core of the light receiving element 108, the passive alignment can be simply achieved by a single step for fixedly inserting the ferrule 114 into the package 115'. The present invention also relates to a multi-optical receiving module comprising at least two optical receiving modules aligned in parallel and then packaged.

Hereinafter, an optical transreceiving module 300 integrally comprising the above-described optical transmitting and receiving modules 100 and 200 in accordance with another preferred embodiment of the present invention will be described in detail with reference to Fig. 9.

As shown in Fig. 9, as described above, the transmitting and receiving guide pipes 118 and 119 connected to a pair of the lens insertion holes 122 and 123 are formed on the front surface of the package 115, and the protuberances 120 and 121 having a designated shape are formed on the bottom surfaces of cavities A and B divided by a diaphragm 305 in the package 115. The concavities 106 and 110 are formed in the bottom surfaces of transmitting and receiving substrates 101 and 107 so that shapes and sizes of the concavities 106 and 110 correspond to those of the protuberances 120 and 121 formed on the bottom surfaces of the cavities A and B of the package 115, thus aligning the bottom surfaces of transmitting and receiving substrates 101 and 107 precisely in the cavities A and B of the package 115.

A socket 310 is integrally attached to a rear surface of the package 115. Contact points C of the socket 310 are horizontally protruded from the package 115 so that the contact points C are easily connected to an external circuit board 320 by coupling the contact points C with a connector 321 formed on the external circuit board 320. An opening for receiving the transmitting and receiving substrates 101 and 107 is formed in the upper surface of the package 115, and a cover 126 is provided on the upper surface of the package 115.

The present invention also relates to a multi-optical transreceiving module comprising at least two optical transreceiving modules aligned in parallel and then packaged .

Hereinafter, a process for manufacturing the above optical transreceiving module will be described in detail. An electrical connection step such as wire bonding is omitted because it is considered to be obvious to those skilled in the art .

The package 115 for an integrated module is seated on a stage (not shown) . The silicon substrate 101 provided with the laser diode 103 and the photo diode 104 for a monitor is picked up, and then mounted in the cavity A of the package 115. Here, the silicon substrate 101 is aligned at a precise position on the bottom surface of the package 115 by the concavity 106 provided with the. slanted side wall formed in the bottom surface of the silicon substrate 101 and the flat bottom surface with a rectangular shape, and the MESA structure 120 provided with the slanted side wall formed on the bottom surface of the cavity A of the package 115 so that the shape and size of the concavity 106 correspond to those of the MESA structure 120. Solder having a designated melting point is coated on the upper surface of the MESA structure 120.

In the same manner, the ceramic block 107 provided with the photo diode 108 is picked up, and then mounted in the other cavity B of the package 115. Here, the ceramic block 107 is aligned at a precise position on the bottom surface of the package 115 by the concavity 110 provided with the slanted side wall formed in the bottom surface of the ceramic block 107 and the flat bottom surface with a rectangular shape, and the MESA structure 121 provided with the slanted side wall formed on the bottom surface of the cavity B of the package 115 so that the shape and size of the concavity 110 correspond to those of the MESA structure 121. Also, solder having a designated melting point is coated on the upper surface of the MESA structure 121.

The stage is heated so that the solder (not shown) coated on the upper surfaces of the MESA structures 120 and 121 is melted, thus fixing the silicon substrate 101 for transmitting light and the ceramic block 107 for receiving light at precise positions in the package 115.

After the silicon substrate 101 for transmitting light and the ceramic block 107 for receiving light are fixed in the package 115, the cover 126 is fixed to the upper surface of the package 115 by electric welding under a nitrogen atmosphere .

After the mounting of the silicon substrate 101 for transmitting light and the ceramic block 107 for receiving light in the cavities A and B is completed, the transmitting ferrule 112 provided with the transmitting optical fiber 111 and the receiving ferrule 114 provided with the receiving optical fiber 113 are inserted into the hollows of the transmitting and receiving guide pipes 118 and 119 prepared in pair and attached to the front surface of the package 115, and then fixed to the hollows by laser welding, or etc.

Industrial Applicability

As apparent from the above description, the present invention provides an optical module, in which a matching circuit for achieving impedance matching with active elements is formed on the upper or lower surface or both surfaces of the inside of a socket structure, thereby minimizing a signal loss or interference between signals and allowing the optical module to be used as an element, which is operable at high speeds more than 2.5 Gbps . Further, the passive alignment is achieved without the operation of a light emitting or receiving element. Moreover, since the optical module is manufactured under the condition that the inner components are aligned in advance, it is possible to reduce the time taken in aligning the components .

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

Claims :

1. An optical transmitting module comprising a substrate provided with active elements attached thereto at designated positions, and a package provided with light collection means for transferring light emitted from a light emitting element to an optical fiber, and electrical contact points located between the active elements and an external circuit board, wherein the package comprises a socket having contact points for electrically connecting the active elements to the external circuit board formed at both terminals of the socket, and a matching circuit for achieving impedance matching with the active elements formed between the contact points, said contact points to be connected to the external circuit board being horizontally protruded from one surface of the package.

2. The optical transmitting module as set forth in claim 1, wherein the matching circuit is formed on a substrate with a designated dielectric constant.

3. The optical transmitting module as set forth in claim 1, wherein the matching circuit is formed to have a multi-layered structure.

4. The optical transmitting module as set forth in claim 1, wherein a protuberance with a designated shape is formed on either one of a bottom surface of the substrate and a bottom surface of a cavity formed in the package, and a concavity corresponding the protuberance is formed in the other one so that a passive alignment is achieved by coupling the protuberance to the concavity.

5. The optical transmitting module as set forth in claim 4, wherein the protuberance having a MESA structure provided with a side wall slanted at a designated angle is formed on the bottom surface of the package .

6. The optical transmitting module as set forth in claim 1, wherein the package is made of a material selected from the group consisting of ceramic, metal, resin, and their equivalents.

7. The optical transmitting module as set forth in claim 1, wherein a guide pipe of the light collection means has an inner diameter the same as an outer diameter of a ferrule so that the ferrule is fixedly inserted into the guide pipe .

8. An optical receiving module comprising a substrate provided with a light receiving element attached thereto at a designated position, and a package provided with light collection means for transferring light from an optical fiber to the light receiving element, and electrical contact points located between the light receiving element and an external circuit board, wherein the package comprises a socket having contact points for electrically connecting the light receiving element to the external circuit board formed at both terminals of the socket, and a matching circuit for achieving impedance matching with the light receiving element formed between the contact points, said contact points to be connected to the external circuit board being horizontally protruded from one surface of the package.

9. The optical receiving module as set forth in claim 8, wherein the matching circuit is formed on a substrate with a designated dielectric constant.

10. The optical receiving module as set forth in claim 8, wherein the matching circuit is formed to have a multi-layered structure.

11. The optical receiving module as set forth in claim 8, wherein a protuberance with a designated shape is formed on either one of a bottom surface of the substrate and a bottom surface of a cavity formed in the package, and a concavity corresponding the protuberance is formed in the other one so that a passive alignment is achieved by coupling the protuberance to the concavity.

12. The optical receiving module as set forth in claim 11, wherein the protuberance having a MESA structure provided with a side wall slanted at a designated angle is formed on the bottom surface of the package .

13. The optical receiving module as set forth in claim 8, wherein the package is made of a material selected from the group consisting of ceramic, metal, resin, and their equivalents.

14. The optical receiving module as set forth in claim 8, wherein a guide pipe of the light collection means has an inner diameter the same as an outer diameter of a ferrule so that the ferrule is fixedly inserted into the guide pipe .

15. An optical transreceiving module integrally comprising the optical transmitting module as set forth in one claim selected from claims 1 to 7 and the optical receiving module as set forth in one claim selected from claims 8 to 14.

16. A multi-optical transmitting module obtained by aligning two or more of the optical transmitting modules as set forth in one claim selected from claims 1 to 7 in parallel and then packaging the modules.

17. A multi-optical receiving module obtained by aligning two or more of the optical receiving modules as set forth in one claim selected from claims 8 to 14 in parallel and then packaging the modules .

18. A multi-optical transreceiving module obtained by aligning two or more of the optical transreceiving modules as set forth in claim 15 in parallel and then packaging the modules .