KR20030090431A - Bidirectional optical module using wavelength divisional multiplexing coupler apparatus - Google Patents

Abstract

PURPOSE: A bidirectional optical module using a WDM(Wavelength Divisional Multiplexing) coupler is provided to manufacture an accurate substrate by using a semiconductor silicon process and a passive alignment method. CONSTITUTION: A bidirectional optical module using a WDM coupler includes a light receiving device(118), a light emitting device(120), a WDM coupler, and a substrate(110). The WDM coupler includes two lines(132a,132b) and a common line. The lines(132a,132b) are optically coupled to the light receiving device(118) and the light emitting device(120). The lines(132a,132b) are unified by the common line. The substrate(110) includes an optical device installation portion(112) and an optical line installation portion(114). The receiving device(118) and the light emitting device(120) are installed on the optical device installation portion(112). The lines(132a,132b) are installed on the optical line installation portion(114).

Description

Bidirectional optical module using wavelength divisional multiplexing coupler apparatus

The present invention relates to a bidirectional optical module having an optical transceiver, and more particularly, a photodiode and a light emitting diode (Laser Diode or Light Emitting Diode) are installed on one substrate. The present invention relates to an optical module capable of bidirectional optical communication by using a single optical fiber by optically coupling a photonic device and a 1 x 2 wavelength multiplexing coupler.

In general, unidirectional optical communication requires a line for transmitting an optical signal from a first point to a second point and a line for transmitting an optical signal from a second point to a first point. On the other hand, the bidirectional optical module is known as an attractive communication means compared to the transmission and reception separation type optical module using two strands because two-way communication is possible using one strand of the optical fiber.

In general, a bidirectional optical module includes a light receiving element, a light emitting element, and a monitor light receiving element for monitoring the light emitting element on one substrate, and is composed of various components for optically coupling the above optical elements to a single optical fiber. . Types introduced to date include TO can type, WDM filter type, and PLC (Planar Lightwave Circuit) type.

Figure 1 shows a bi-directional optical module of the TO can type as the prior art 1. The TO can type includes a beam splitter (BS) and an optical fiber (f) which allow the light receiving element (PD) and the light emitting element (LD) to be perpendicular to each other and pass only a specific wavelength or beam in a direction parallel to the light emitting element (LD). It is installed in turn. That is, the beam incident from the optical fiber f is reflected by the beam splitter BS and received by the light receiving element PD, and the beam oscillated by the light emitting element LD passes through the beam splitter BS to optically couple with the optical fiber. It has a structure. In the TO can type, each optical part is bonded to the main body by a laser welding method. Since the optical coupling efficiency is low because the distance between the optical fiber and the optical device is far, a lens is provided between the light receiving device, the light emitting device, and the beam splitter. In this TO can method, the alignment between the optical fiber, the beam splitter, the lens, the light-receiving elements, and the alignment between the light emitting element, the lens, the beam splitter, and the optical fiber is very difficult. Therefore, the number of parts to be packaged by the active alignment method is also required. There are many disadvantages.

FIG. 2 is a view illustrating a bidirectional optical module using a wavelength multiplexing filter as the prior art 2. As shown in FIG. In the WDM filter method, a light emitting device 12 is bonded on a silicon substrate 10 having a terrace, and a glass substrate is provided at a lower portion of the terrace. The light receiving element 16 is bonded on the glass substrate 14, and the optical fiber 18 is positioned at the bottom of the light receiving element 16 along the U-groove on the glass substrate 14 and at the end of the optical fiber 18. 24 is provided, and another optical fiber 30 is provided between the filter and the light emitting element. As described above, the WDM filter method requires two kinds of substrates that require precise processing of submicrometers, and requires high precision in packaging, and thus, manufacturing and processing costs are very high.

The present invention is to solve the problems of the conventional bidirectional optical module described above, by manufacturing a precise substrate using a semiconductor silicon process already established as a standard process and using a passive alignment method (Passive Alignment) using the same, inexpensive and simple It is an object of the present invention to provide a bidirectional optical module that can be formed.

1 is a block diagram of a bidirectional optical module of the TO can type as a prior art;

2 is a block diagram of a bidirectional optical module using a WDM filter as a prior art 2;

3 is a schematic perspective view of a bidirectional optical module using a WDM coupler as Embodiment 1 of the present invention;

4 is a plan view of the bidirectional optical module shown in FIG.

5 is a cross-sectional view taken along the line a-a shown in FIG. 4;

FIG. 6 is a cross-sectional view taken along the line b-b shown in FIG. 4; FIG.

FIG. 7 is a cross-sectional view taken along line c-c shown in FIG. 4; FIG.

Figure 8 is an enlarged cross-sectional view of the main portion of the light receiving element installation portion in the bidirectional optical module of the present invention.

9 is an enlarged cross-sectional view of main parts of a light emitting device installation unit in the bidirectional optical module of the present invention;

FIG. 10 is a schematic exploded perspective view of a bidirectional optical module having a groove for a branch / coupling portion of a WDM coupler as a second embodiment of the present invention.

The bidirectional optical module of the present invention for achieving the above object has a light receiving element, a light emitting element and a light receiving element for a monitor, two lines of optically coupled with the light receiving element and the light emitting element and a common line integrating two lines. And a substrate on which the wavelength multiplexing coupler device, the light receiving element, the light emitting element, and the wavelength multiplexing coupler device are installed. In this case, a metal pattern for electrically connecting various optical elements with an external circuit may be formed on the substrate.

In the present invention, the wavelength multiplexing coupler device takes the general form of branching from one common line to two branch lines. Therefore, the shape of the letter Y is approximately the same. The two lines of the wavelength multiplexing coupler device are respectively installed on the substrate to be fixed and optically coupled in alignment with the optical waveguide inside the chip of the light receiving element and the light emitting element. One common line may be composed of an optical fiber or other optical waveguide that is optically coupled to the external optical path of the bidirectional optical module, or may be formed of one end of the optical fiber or other optical waveguide forming the external optical path.

In the present invention, the wavelength multiple division coupler device may use a single component of a wavelength divisional multiplexing (WDM) coupler. In this case, the wavelength of the optical signal for reception and the wavelength of the optical signal for transmission used in the bidirectional optical module generally have different wavelengths such as 1.55 um and 1.3 um.

In the present invention, an alignment groove may be provided in the substrate to align the two lines with the light emitting device and the light receiving device. In this case, the two alignment grooves may be formed in different sizes.

A cap may be partially used to fix the optical fiber on the substrate, and an adhesive flow preventing groove may be further formed on the upper surface of the substrate to prevent the adhesive applied to the optical fiber from flowing into the optical device.

For example, embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape of the elements in the drawings and the like are exaggerated to emphasize a clearer description.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 3 to 10. In addition, in the drawings, the same reference numerals are denoted together for components that perform the same function.

(Example 1)

3 is a perspective view schematically showing the configuration of a bidirectional optical module using a wavelength multiplexing coupler as an embodiment of the present invention, and FIGS. 4 to 9 are cross-sectional views of respective parts of the bidirectional optical module.

Referring to Figure 3, the bidirectional optical module according to a preferred embodiment of the present invention has a light receiving element, a light emitting element, a wavelength multi-division coupler, and a substrate.

The wavelength multiple division coupler has two lines optically coupled to the light receiving element and the light emitting element, a common line integrating the two lines, and uses a WDM (Wavelength Divisional Multiplexing) coupler.

3 to 9, the substrate 110 is divided into an optical device mounting portion 112 and a light path mounting portion 114 on an upper surface thereof, and an adhesive flow preventing groove ( 116 is installed. The light receiving device 118 and the light emitting device 120 are installed in the optical device installation unit 112 of the substrate 110. A V-groove 128 is formed on the rear surface of the light emitting device 120, and a monitor light-receiving device 122 for monitoring the light emitting device 120 is installed at an end of the V-groove 128. In this case, a reflective surface 129 may be formed at the end surface of the V-groove 128, and the light emitted from the light emitting device 120 may be reflected from the end surface of the monitor light receiving device 122 so that the light emitting device In order to return to 120 and prevent the performance of the light emitting device from deteriorating, the monitor light receiving device 122 may be inclined with respect to the light direction.

In addition, V-shaped alignment grooves 124 and 126 are formed at portions where the receiving and light emitting elements 118 and 120 are positioned so that the optical fiber can be guided from the direction of the optical path mounting portion 114. 5 and 7, in the case of the light receiving element 118, the alignment groove 126 is deep so that the optical fiber can be led to the lower portion of the middle of the light receiving element 118. Reflecting surface 127 is provided. Each optical element, that is, the light receiving element 118, the light emitting element 120, and the monitor light receiving element 122 has a respective electrical terminal and is connected to an electrical connection pad provided on the substrate 110.

The light path mounting portion 114 of the substrate 110 is a portion where two lines 132a and 132b of the wavelength multiplexing coupler device 130 are mainly installed. V-shaped alignment grooves 124 and 126 are formed on the upper surface of the substrate 110 at the portion where the two lines 132a and 132b are installed, and thus may be used for manual alignment of the branch lines 132a and 132b. Alignment grooves 124 and 126 of the substrate are also partially formed in the optical device installation unit 112 so that branch lines 132a and 132b can be directly optically coupled to the photons as they approach maximum.

8 and 9 are cross-sectional side views of the light emitting device 120 and the light receiving device 118, respectively, illustrating the optical coupling principle between the optical device and the optical fiber.

In general, the light receiving portion of the light receiving element is generally located below the center of the chip constituting the light receiving element, and the light emitting portion of the transmitting light emitting element or the optical waveguide connected to the light emitting portion is located at the lower side of the chip constituting the light emitting element. Oscillates light in parallel bidirectional directions.

As described above, the alignment groove 126 in which the branch line 132b to be coupled to the light receiving element 118 is installed is deeply formed so that the end of the optical fiber forming the branch line 132b as shown in FIG. 8 is formed on the substrate 110. It is preferable to install the fiber core at a level below the upper surface of the substrate by installing the same or lower several um as the upper surface. In FIG. 8, at the end of the alignment groove 126, the inclined surface below the chip of the light receiving device 118 is formed with a mirror surface 127 that reflects the light from the optical fiber core and sends it to the light receiving device light receiving unit.

6 and 9, the alignment groove 124 in which the branch line 132a to be coupled to the light emitting device 120 is installed is formed relatively shallow so that the core of the optical fiber forming the branch line 132a is installed here. Is positioned at a high level on the upper surface of the substrate 110 to match the height of the waveguide 121 of the light emitting device 120. In addition, the light oscillating toward the rear surface of the light emitting device 120 is incident to the monitor light receiving device 122 through the reflective surface 129 of the end surface of the V-groove 128 installed behind the light emitting device 120. . After the two optical fibers constituting the branch lines (132a, 132b) in the optical path installation portion 114 of the substrate 110 by the same principle as in the optical coupling with the photons (118, 120, 122) It is fixed by an adhesive or the like. At this time, the lid 150 may be covered with the mounting portion 114 of the light beam of the substrate 110 to ensure the alignment state. The optical fiber which forms a common line is connected to the external light path. Alignment grooves may be formed in the lid 150 at positions corresponding to the alignment grooves formed in the substrate 110.

(Example 2)

10 is a schematic exploded perspective view for illustrating the configuration of a bidirectional optical module constituting Embodiment 2 of the present invention. This embodiment 2 has the same configuration as in the first embodiment, and has a difference only in the light path mounting portion 114 of the substrate 110.

As shown in FIG. 10, the second embodiment is a branch / combination in which two lines are combined into one common line in the wavelength multiplexing coupler device 130 on a portion of the optical path mounting portion 114 on the substrate 110. A separate groove 115 is formed for the coupling part 136. In this case, the lid 150 may be provided in the light path mounting portion 114 to protect the alignment state.

In the above, the configuration and operation of the bidirectional optical module according to the present invention is shown in accordance with the above description and drawings, but this is only an example, and various changes and modifications are possible within the scope without departing from the technical spirit of the present invention. Of course.

According to the present invention, since the number of components is smaller than that of the conventional bidirectional optical module and can be formed by a manual alignment method, it is possible to implement a cheap and simple bidirectional optical module.

Claims (11)

A light receiving element; A light emitting element; A wavelength multiplexing coupler device having two lines optically coupled to the light receiving element and the light emitting element, and a common line integrating the two lines; And a substrate having an optical element mounting portion on which the light receiving element and the light emitting element are installed, and a light ray mounting portion on which two lines of the wavelength multiplexing coupler device are installed. The method of claim 1, And the wavelength multiple division coupler device uses a single wavelength divisional multiplexing (WDM) coupler. The method of claim 1, An alignment groove in which the two lines are installed is formed in the light path installation portion of the substrate; And an alignment groove corresponding to the branch line optically coupled to the light emitting device is smaller than an alignment groove corresponding to the branch line optically coupled to the light receiving element. The method of claim 3, wherein And an alignment groove corresponding to a common line of the wavelength multiplexing coupler is formed in the light path installing portion of the substrate. The method of claim 4, wherein And the two lines and the common line are fixedly installed in alignment grooves formed on the substrate, respectively. The method of claim 4, wherein The two lines are fixedly installed in the alignment grooves formed on the substrate, Two-way optical module is characterized in that the alignment grooves are installed differently formed in a different size. The method of claim 3, wherein The two light paths are aligned with the alignment grooves provided on the substrate, Bidirectional optical module, characterized in that for covering the top of the light path. According to claim 7, And at least one alignment groove corresponding to the alignment groove of the optical path on the substrate is formed under the lid of the upper portion of the optical path. The method of claim 8, Alignment grooves are formed in the lower part of the lid for receiving light paths and transmitting light beams, The bidirectional optical module, characterized in that the size of the alignment groove is formed in the light beam. The method of claim 8, An alignment groove is formed in the lower portion of the lid with a light beam, And a groove corresponding to a branch / coupling portion of the wavelength multiplexing coupler is formed at one end of the optical fiber alignment groove. The method of claim 3, wherein Bidirectional optical module, characterized in that the adhesive flow preventing groove is formed on the upper surface of the substrate.