Optical module

An optical module includes: a circuit board having a surface in which an electronic element is mounted; an optical waveguide array in which a plurality of optical waveguides are formed; an optical element in which an optical signal that is transmitted and received from and to the optical waveguide is input and that is mounted at a side surface of the circuit board; and a connection member that connects the optical element and the electronic element, wherein a connection portion of a side surface of the circuit board in which the connection member is received has a curved shape.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2015-0007148 filed in the Korean Intellectual Property Office on Jan. 15, 2015, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to an optical module. More particularly, the present invention relates to an optical module that transfers an electric signal that is generated according to an applied optical signal to a circuit board.

(b) Description of the Related Art

In general, in a low speed system, a connection between circuit boards and between chips or between systems is performed through a metal electrical cable. However, as in a next generation information communication system that is formed with a large capacity parallel computer or an ATM switching system having a capacity of 1 Tb/s or more, as a large amount of information is transmitted and transmission speed is improved, when using such a metal cable, an electrical problem such as skew and electromagnetic interference (EMI) occurs and thus operation efficiency of the system is deteriorated and it is difficult to integrate a system.

Therefore, technology that performs an optical connection using an optical transmitting/receiving module has been developed, and a method of directly coupling an optical receiving element to a ribbon optical fiber multichannel optical connector having a reflector that is located with a tilt angle of 45° with an optical coupling method within the optical transmitting/receiving module, a method of coupling an optical transmitting/receiving element to a polymer optical waveguide having a reflector that is located with a tilt angle of 45° and connecting the polymer optical waveguide to a multichannel optical connector, a method of vertically coupling an optical transmitting/receiving element to a polymer optical waveguide and connecting the polymer optical waveguide to a multichannel optical connector, and a method of vertically coupling an optical transmitting/receiving element that is fixed to a plastic package to a multichannel optical connector are used. In this case, as an optical transmitting element, i.e., an optical source, a Vertical Cavity Surface Emitting Laser (VCSEL) array is used, and as optical receiving element, i.e., an optical detector, a photodiode (PD) array is used.

A conventional optical module reflects light that is oscillated through a light emitting port by 90° by an optical waveguide and transfers the light to an optical fiber that is connected to an optical connector along a core that is formed in a board. “ParaBIT-1: 60-Gb/s-Throughput Parallel Optical Interconnect Module, presenter: N. Usui” that was published in ECTC 2000 in May of 2000 has a structure in which a 24 channel polymer waveguide film in which a plane reflector is located with a tilt angle of 45° and a 24-optical fiber BF connector are connected, and the waveguide film and the connector are manually assembled.

In this technology, because a method of coupling an optical transmitting/receiving element to a polymer optical waveguide having a reflector that is located with a tilt angle of 45° and connecting a polymer optical waveguide to a multichannel optical connector may relatively easily form a reflector and house an optical coupler, an optical switch, and a Wavelength Division Multiplexing (WDM) element in a polymer optical waveguide, the method can extend a function of an entire module and is thus evaluated as a very effective method.

However, in order to produce an optical transmitting/receiving module for parallel optical connection having an extending function, when using the optical coupling technology, even if a small misalignment occurs in coupling of the optical transmitting/receiving element and an optical fiber, a large optical coupling loss occurs and thus satisfactory efficiency is not obtained. Therefore, structure enhancement of an optical transmitting/receiving module for parallel optical connection that can minimize a coupling loss is urgently requested.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide an optical module having advantages of being capable of preventing a loss such as optical coupling efficiency reduction and a loss of bandwidth occurring due to rapid direction conversion of an electric signal line when transmitting a high speed signal.

An exemplary embodiment of the present invention provides an optical module including: a circuit board having a surface in which an electronic element is mounted; an optical waveguide array in which a plurality of optical waveguides are formed; an optical element in which an optical signal that is transmitted and received from and to the optical waveguide is input and that is mounted at a side surface of the circuit board; and a connection member that connects the optical element and the electronic element, wherein a connection portion of a side surface of the circuit board in which the connection member is received has a curved shape.

The connection member may be curvedly formed along a curved shape of a connection portion of a side surface of the circuit board.

A connection portion of a curved shape of a side surface of the circuit board may be formed with a rod that is made of glass.

The glass rod may have a cross-sectional shape of a quarter of a circle.

The optical element may be formed in a direction opposite to that of the electronic element in the circuit board, and the glass rod may be installed at a side surface of the circuit board.

The connection member may include a transmission line, and a wire bonding unit that connects the electronic element and the optical element at both ends of the transmission line.

The transmission line may be formed in a pattern in the glass rod.

An optical module according to an exemplary embodiment of the present invention can simplify a production process by forming a transmission line in a glass rod.

Further, by minimizing a loss of an electric signal by forming a curved surface using a glass rod, a bandwidth can be extended and various angles of transmission line can be implemented.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Further, in the drawings, a size and thickness of each element are randomly represented for better understanding and ease of description, and the present invention is not limited thereto.

FIG. 1is a perspective view illustrating an optical module according to a first exemplary embodiment of the present invention.

Referring toFIG. 1, a circuit board10in which a plurality of electronic elements40and an optical element30are mounted and an optical waveguide array20in which a plurality of optical waveguides22are connected are coupled to form an optical module100. The plurality of optical waveguides22are arranged parallel to the optical element30and an optical signal is input thereto, and a signal that is generated in the optical element30is transferred to the electronic element40through a connection member50.

The optical waveguide array20is installed at a side surface of the circuit board10, and a guide unit may be formed to not separate from a predetermined location.

In the optical waveguide array20, a plurality of optical elements30are mounted at a side surface of the circuit board10to correspond to the plurality of optical waveguides22.

The electronic element40is mounted at an upper surface of the circuit board10, and is connected to the optical element30that is mounted at a side surface of the circuit board10with the connection member50. The connection member50may be formed with a transmission line52and a wire bonding unit54. The transmission line52is located between the electronic element40and the optical element30, and the transmission line52, the electronic element40, and the optical element30are connected by the wire bonding unit54. Therefore, the transmission line52is located between a side surface and an upper surface of the circuit board10, i.e., at a corner of the circuit board10.

A corner of the circuit board10in which the transmission line52is located may be a curvedly formed curved surface60. When the transmission line52is located at a vertically formed surface, if an electric signal is transferred to the electronic element40along the transmission line52that is located at the curved surface60, a loss of an electric signal or heat occurring on the transmission line52can be reduced.

FIG. 2is a cross-sectional view illustrating a portion of an optical module according to a first exemplary embodiment of the present invention.

Referring toFIG. 2, the transmission line52is located at a curvedly formed corner of the circuit board10, and a glass rod62is inserted into the curvedly formed curved surface60of the circuit board10to form a curved shape. A description of the configuration of the optical cable array20will be omitted.

The glass rod62is inserted into a corner portion of the circuit board10, and the transmission line52is located at a surface of the glass rod62. The glass rod62may function as a dielectric material.

After coating an electrode at the glass rod62, the transmission line52may form a transmission line in a pattern in the glass rod62using infrared ray short pulse laser.

In more detail, in the transmission line52, titanium, nickel, or chrome having good adhesion with the glass rod62is used, and the transmission line52may be plated with a method such as Au sputtering or Au plating. Further, according to a bandwidth of the transmission line52and a line width and a line gap that are determined according to an impedance matching structure such as a coplanar waveguide and a microstrip line, the transmission line52may be produced using a short pulse laser having a pulse width of several nanoseconds (ns) of an infrared ray wavelength band of 1064 nm or more having good transmittance and a low absorption rate to glass.

When the transmission line52is produced in this way, damage is reduced in the glass rod62that performs a dielectric material function and thus an impedance change of the transmission line52is minimized, thereby reducing a signal loss and noise.

Further, because the transmission line52may be directly formed in the glass rod62without separate mask production, cost can be reduced and a path can be smoothly changed through the transmission line52that is disposed along a circumference of the glass rod62and thus a bandwidth loss can be minimized. Further, by simplifying a production process, an optical module can be formed with a low price. Further, the signal transmission line52of various angles can be implemented according to a shape of the glass rod62and an electrode.

FIG. 3is a cross-sectional view illustrating a portion of an optical module according to a second exemplary embodiment of the present invention.

Referring toFIG. 3, a quarter of a glass rod64is inserted into a corner of a circuit board10. The corner of the circuit board10is vertically formed, and the quarter of the glass rod64is coupled to the corner of the circuit board10. Therefore, the optical module according to a second exemplary embodiment has a merit that the quarter of the glass rod64can be easily inserted into the circuit board10and that an optical module100can be formed in a small size, compared with the optical module100of the first exemplary embodiment.

FIG. 4is a cross-sectional view illustrating a portion of an optical module according to a third exemplary embodiment of the present invention.

Referring toFIG. 4, a glass rod62is inserted into a side surface of a circuit board10, an electronic element40is located at a upper surface of the circuit board10, and an optical element30may be located at a lower surface of the circuit board10, which is a direction opposite to that of the electronic element40.

The optical element30is located at a lower surface of the circuit board10. Therefore, because the optical element30may receive an input of an optical signal at a lower surface of the circuit board, the optical waveguide array20(seeFIG. 1) and the circuit board10can be variously connected. By inserting the glass rod62into a side surface of the circuit board10, the optical module can be easily produced.