KR100476685B1 - Optical Interconnection Module Assembly and Packaging Method thereof - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to optical communication components, and more particularly, to an optical coupling module assembly and a packaging method thereof. According to the present invention, the alignment and coupling structure of each component is simple and can be easily manually aligned without using expensive equipment, and the horizontal indirect coupling is achieved without increasing the manufacturing cost and complexity of the optical coupling structure according to the application of the monitoring photodetector. It is an object of the present invention to provide an optical coupling module assembly and a packaging method thereof. The present invention compensates for the shortcomings based on a horizontal indirect coupling structure having a relatively simple coupling structure for optical coupling between an optical device and an optical fiber. That is, the present invention used a silicon optical bench to facilitate the alignment of each component. The silicon optical bench has an alignment V-groove for easy manual alignment with guide pins built into the adapter and lens. In addition, the present invention can reduce the manufacturing cost by using a plastic mold lens that is easy to process, as well as can be easily manufactured using a method of inclining the light incident surface of the lens when the monitoring photodetector is coupled.

Description

Optical Interconnection Module Assembly and Packaging Method

TECHNICAL FIELD The present invention relates to optical communication components, and more particularly, to an optical coupling module assembly and a packaging method thereof.

Recently, interest in communication lines and optical communication equipment requiring ultra-high speed data communication of several tens of Gbps or more in a short range of about 200m is increasing. Next-generation Gigabit Ethernet (ETHERNET) devices, ultra-fast computers and peripherals, ultra-high-capacity workstations and client computers signal high-speed data optically for short-range transmission optical coupling modules that process ultra-high-speed data communications in excess of tens of Gbps. It is a representative device using.

Optoelectronic devices, such as VCSEL (Vertical Cavity Surface Emitting Laser) devices, photodetectors, etc., are a core technology among optical fiber module manufacturing technologies.

In the conventional short-range transmission optical coupling module, there are two structurally coupled methods of the array-type VCSEL chip and the array-type photodetector to the optical fiber, which are a horizontal coupling method and a vertical coupling method. The horizontal coupling method is a case where the traveling direction of light emitted from the light source and the propagation direction of the light propagating through the optical fiber are the same, and the vertical coupling method is a case where the traveling direction of the emitted light and the propagation propagation direction in the optical fiber are vertical.

1 is a perspective view of a horizontal direct coupling structure of a VCSEL chip and an optical fiber according to the prior art.

The horizontal coupling structure shown in FIG. 1 uses a method in which light emitted from the VCSEL chip 100 is directly coupled with the optical fiber cable 101 without passing through any optical system. US Pat. Nos. 6,315,463 and 6,227,720 are technologies that correspond to this horizontal direct coupling structure.

Referring to FIG. 1, the horizontal direct coupling method creates two guide holes 104 in a substrate 102 on which a VCSEL chip 100 is bonded and aligns with the guide pins 103 of an optical fiber cable connector 105. Allow optical coupling. The horizontal direct coupling method utilizes the advantages of the VCSEL laser having surface emission and circular beam characteristics as it is, and has an advantage of a very simple structure.

However, this horizontal direct coupling method has a risk of damaging the VCSEL laser window due to the detachment of the optical fiber cable 101, the bonding wire between the VCSEL chip 100 and its drive circuit is attached to the detachment of the optical fiber cable 101. There is a risk of damage. In order to eliminate such a hazard, the optical coupling efficiency is reduced when the optical fiber cable 101 and the VCSEL chip 100 are separated by a predetermined distance or more. Above all, the biggest problem of the horizontal direct coupling method is that it is difficult to combine the monitoring photodetector for monitoring the operating performance of the light source, and the structure becomes very complicated when combined. In addition, since the optical device chip and the driving and receiving circuit chip existing in the optical module are exposed to the outside air as it is, there is a problem that the possibility of corrosion and oxidation is very high.

On the other hand, in the case of the back-emitting VCSEL, the electrodes of the P and N electrodes are generally present on the front of the VCSEL chip, thereby reducing the possibility of damaging the wire and the laser window by bonding the substrate to the substrate by flip chip bonding. In order to fabricate, there is a limitation to use a wavelength (eg, 980 nm) that can pass through GaAs used as the substrate of the VCSEL chip. In addition, the technique of fabricating the electrodes of the P pole and the N pole of the back light emitting VCSEL on the same surface is a very difficult technique, and the manufacturing cost is also high. Therefore, these back-emitting VCSELs are more advantageous in the N × N two-dimensional array structure than the 1 × N type one-dimensional linear array structure. However, even when the optical fiber is directly bonded by using the back-emitting VCSEL array, the blocking of the outside air is also not performed, and thus the risk of corrosion and oxidation still exists.

2 is a cross-sectional view of a horizontal indirect coupling structure of a VCSEL chip and an optical fiber according to the prior art.

The horizontal coupling structure shown in FIG. 2 uses a method in which light emitted from the VCSEL chip 112 is coupled to the optical fiber 111 through the lens 110. 2, in the horizontal indirect coupling method, since the optical coupling between the VCSEL chip 112 and the optical fiber 111 is performed through the lens 110, the horizontal coupling structure is directly coupled without the lens 110 (FIG. 1) can solve a lot of problems. In other words, by employing the lens 110, by breaking a predetermined distance between the VCSEL chip 112 and the optical fiber 111, it is possible to prevent the breakage of the bonding wire and the damage of the laser window (light emitting aperture), the lens 110 By this, the effect of blocking the VCSEL chip 112 from outside air can be obtained, and corrosion and oxidation can be prevented. In addition, the monitoring photodetector 115 is easy to install, and since the photodetector 115 and the VCSEL chip 112 exist in the same plane, they are advantageous for alignment and packaging, and the light emitted from the VCSEL chip 112 is an optical fiber ( 111) has the advantage of increased efficiency and increased alignment tolerance.

Conventionally, in order to form the lens 110, a method of forming a photoresist on a substrate 113 such as glass using a photoresist, an ion exchange method, a method by laser writing [HP Herzig, P. (ed) (1997) Micro -optics elements, systems and applications [ see Taylor & Francis], etc., these methods have a disadvantage in that the manufacturing cost increases because they have to be manufactured using a precise photo processing process or using equipment with expensive precision controllers. In addition, since alignment between the VCSEL chip 112 and the lens 110, the lens holder 114 and the lens 110, and the lens 110 and the optical fiber 111 must be precise, respectively, there is a difficulty in alignment. .

3 is a cross-sectional view of a vertical coupling structure of a VCSEL chip and an optical fiber according to the prior art.

The vertical coupling structure shown in FIG. 3 uses a method of grinding the end portion of the optical fiber 121 at 45 angles to form a reflective surface and then bending the reflected light by 90 degrees to combine the optical fiber 121. Regarding this technology, a number of US patents [US 6,012,855, US 5,999,670, US 6,069,991] and articles [H. Karstensen, et. al., "Parallel Optical Link (PAROLI) for Multichannel Gigabit Rate Interconnections," IEEE ECTC pp. 747-754, April 4, 2000 Mary K. Hibbs-Brenner et al.

The advantage of this vertical coupling method is that monitoring the light reflected from the reflective surface of the polished optical fiber 121 because the monitoring photodetector 122 is present on the path of the light emitted from the VCSEL chip 120 is a horizontal coupling structure. Compared to the case with the lens (see Fig. 2) is easy.

However, this technique has a difficulty in precisely polishing the optical fiber 121, and because the optical coupling through the optical path conversion, the structure is very complicated, so that the alignment is very difficult.

Reference numeral '123' represents a control circuit for controlling the light output of the VCSEL chip 120 by feeding back the monitoring result through the monitoring photodetector 122.

The present invention has been proposed to solve the problems of the prior art as described above, the optical coupling module assembly and its packaging method that can be easily manually aligned without the use of expensive equipment, the alignment and coupling structure of each component is simple The purpose is to provide.

It is also an object of the present invention to provide an optical coupling module assembly and a packaging method thereof, which can achieve horizontal indirect coupling without increasing the manufacturing cost and complexity of the optical coupling structure according to the application of the monitoring photodetector.

According to an aspect of the present invention for achieving the above technical problem, an optical fiber cable connector with a built-in optical fiber; An adapter in which the optical fiber cable connector is plug-in, and in which a plurality of first alignment guide pins are embedded; A printed circuit board having a control circuit; A silicon optical bench mounted on the printed circuit board and having a plurality of first alignment V-grooves corresponding to the first alignment guide pins; An optoelectronic device mounted on the silicon optical bench; An optical coupling lens created on the silicon optical bench to cover the optoelectronic device; And an optical module package housing for protecting the printed circuit board.

According to another aspect of the invention, the method of packaging the optical coupling module assembly of claim 1, comprising the steps of: bonding the optoelectronic device to the silicon optical bench using a solder and bonding wire; Mounting the optical coupling lens on the silicon optical bench; Mounting the silicon optical bench on the printed circuit board using an epoxy; Fastening the optical fiber cable connector and the adapter in a plug-in manner; And coupling the adapter coupled with the optical fiber cable connector to the printed circuit board on which the silicon optical bench is mounted using the first alignment guide pin and the first alignment V-groove. A method of packaging a module assembly is provided.

The present invention compensates for the shortcomings based on a horizontal indirect coupling structure having a relatively simple coupling structure for optical coupling between an optical device and an optical fiber. That is, the present invention used a silicon optical bench to facilitate the alignment of each component. The silicon optical bench has an alignment V-groove for easy manual alignment with guide pins built into the adapter and lens. In addition, the present invention can reduce the manufacturing cost by using a plastic mold lens that is easy to process, as well as can be easily manufactured using a method of inclining the light incident surface of the lens when the monitoring photodetector is coupled.

Hereinafter, preferred embodiments of the present invention will be introduced in order to enable those skilled in the art to more easily carry out the present invention.

4 is a block diagram of an optical coupling module assembly according to an embodiment of the present invention.

Referring to FIG. 4, the optical coupling module assembly according to the present exemplary embodiment includes a fiber optic cable connector 1, an adapter 4, and an optical module package 7.

The optical fiber cable connector 1 uses commercially available products (eg, MPO connector, SMC connector, etc.). The optical fiber cable connector 1 incorporates an optical fiber array 2 at the center thereof, and has an optical fiber cable guide pin 8 for optical coupling with the VCSEL chip 20 at the lower portion thereof.

The adapter 4 serves as a guide so that the optical fiber array 2 of the optical fiber cable connector 1 is inserted and optically coupled with the VCSEL chip 20. The adapter 4 is provided with a hole into which the adapter fixing bolt 5 is to be inserted at both ends, and below the two guide pins 3 protruding from the adapter housing.

The optical module package 7 includes a plastic mold lens 10, a VCSEL chip 20, a silicon optical bench 30, a printed circuit board 40, and a plastic housing 50. The silicon optical bench 30 is mounted on the printed circuit board 40, and the VCSEL chip 20 is mounted on the silicon optical bench 30. In addition, a plastic mold lens 10 is provided to overlap the VCSEL chip 20 for optical coupling between the optical fiber array 2 and the VCSEL chip 20, and the printed circuit board 40 except for the silicon optical bench 30. The plastic housing 50 is provided to surround the same.

Meanwhile, four lens mounting V-grooves are engaged with the alignment pins 11 of the plastic mold lens 10 in the silicon optical bench 30 to align and couple the plastic mold lens 10 to the silicone optical bench 30. And two guide V-grooves for engaging and aligning the adapter 4 coupled with the optical fiber cable connector 1 to the silicone optical bench 30 in engagement with the guide pin 3 of the adapter 4. 32).

The plastic housing 50 includes a housing bolt hole 51 and a housing guide pin hole 52 corresponding to the adapter fixing bolt 5 and the optical fiber cable guide pin 8, and the printed circuit board 40. The substrate bolt hole 41 and the substrate guide pin hole 45 corresponding to the adapter fixing bolt 5 and the optical fiber cable guide pin 8 are provided.

In addition, the adapter 4 to which the optical fiber cable connector 1 is coupled is fixed to the printed circuit board 40 and the plastic housing 50 using the bolt 5 and the nut 6. The bolt 5 is coupled to the nut 6 through the housing bolt hole 51 and the substrate bolt hole 41 to engage and fix the component.

Hereinafter, the packaging process of each component of the optical module will be described in sequence.

5 is an alignment state diagram of the silicon optical bench of FIG. 4 and the array VCSEL chip of FIG. 4, (a) is a plan view, and (b) is a cross-sectional view.

First, as shown in FIG. 5A, the silicon optical bench 30 on which the alignment marks 33, the solder 34, the guide V-groove 32, the lens mounting V-groove 31, and the like are formed. Next, the array VCSEL chip 20 is aligned using the alignment mark 33. Next, the array VCSEL chip 20 is bonded to the silicon optical bench 30 using the solder 34. At this time, the rear surface of the array VCSEL chip 20 has an alignment mark (not shown) and a flip chip solder pad (not shown) to enable flip chip bonding to the silicon optical bench 30.

FIG. 5B illustrates a cross section of the silicon optical bench 30 after the array VCSEL chip 20 is bonded to the silicon optical bench 30, compared with the planar state of FIG. 5A. The guide V-groove 32 and the lens mounting V-groove 31 are hard to appear in the same cross section, but they are shown together for better understanding.

6 is an alignment diagram of a silicon optical bench and a plastic mold lens in which an array VCSEL chip is mounted.

After the packaging process shown in FIG. 5 is finished, the electrodes formed on the array VCSEL chip 20 and the silicon optical bench 30 mounted on the silicon optical bench 30 as shown in FIG. (35) is connected using the wire 36. Here, each P-pole on the array VCSEL chip 20 is wire-bonded separately with the electrode 35, but the bottom surface of the array VCSEL chip 20 is commonly in contact with the N-pole to be electrically connected to the solder 34. do.

Next, the lens mounting V-groove 31 and the alignment pin 11 of the plastic mold lens 10 are aligned, and as shown in FIG. 6B, the plastic mold lens 10 and the silicon optical bench. Combine 30. In this case, epoxy may be filled and bonded between the alignment pin 11 of the plastic mold lens 10 and the guide groove 31 of the silicon optical bench 30.

FIG. 7 is a conceptual view illustrating a beam path when light emitted from the array VCSEL chip 20 passes through the plastic mold lens 10, and the plastic mold lens 10 is also provided in an array form. Since only one lens is shown.

FIG. 8 is a view illustrating a state in which the optical coupling submount 37 formed through the packaging process illustrated in FIGS. 5 and 6 is mounted on the printed circuit board 40.

FIG. 8A is a plan view of the printed circuit board 40. The printed circuit board 40 includes a substrate bolt hole 41, a substrate guide pin hole 45, and an optical coupling submount 37 for alignment. An electronic drive control circuit 42 for driving the alignment mark 43 and the array VCSEL chip 20 is formed.

FIG. 8B is a cross-sectional view of the silicon optical bench 30 bonded to the printed circuit board 40 by using the epoxy 44. After the packaging process as described above, the optical module shown in FIG. The package 7 is completed.

Thereafter, the optical fiber cable connector 1 and the adapter 4 are fastened in a plug manner, and the optical fiber cable connector 1 is fastened to the printed circuit board 40 to complete packaging of the optical coupling module assembly. At this time, the guide groove 31 of the silicon optical bench 30 and the guide pin 8 of the optical fiber cable connector 1 are aligned, and then the adapter 4 and the printed circuit board 40 are bonded with epoxy. .

9 is an alignment diagram of an optical module including a monitoring photodetector.

In the case of a system requiring the monitoring photodetector 21, the monitoring photodetector 21 is mounted on the same main surface of the silicon optical bench 30 adjacent to the array VCSEL chip 20 as shown in FIG. 9. At this time, the alignment mark 63 for aligning the monitoring photodetector, the solder 64 for bonding the monitoring photodetector, and the electrode for driving the monitoring photodetector 65 on the silicon optical bench 30 to additionally mount the monitoring photodetector 21. ) May be additionally formed.

10 shows the shape of the plastic mold lens 10 when the monitoring photodetector 21 is included and the beam path when the light emitted from the array VCSEL chip 20 passes through the plastic mold lens 10. As a conceptual diagram, the plastic mold lens 10 is also provided in the form of an array, but in the figure only one lens is shown since the side cross section is shown.

Referring to FIG. 10, the light emitted from the array VCSEL chip 20 is focused through the plastic mold lens 10 to be optically coupled with an optical fiber array (not shown), and to transmit light to the monitoring photodetector 21. In order to give a slope to the main surface of the plastic mold lens (10). At this time, the inclination of the main surface is high so that the monitoring photodetector 21 side and the array VCSEL chip 20 side is low, and the degree of inclination is determined according to the separation distance between the array VCSEL chip 20 and the monitoring photodetector 21. do. As such, when the main surface of the plastic mold lens 10 is inclined, a portion of the light emitted from the array VCSEL chip 20 is reflected on the inclined surface and optically coupled to the monitoring photodetector 21 as shown.

As described above, in the present invention, the guide pin for alignment is incorporated in the adapter coupled to the optical fiber cable connector to enable simple assembly without additional equipment such as a chuck.

On the other hand, it is possible to precisely and easily manufacture the V-groove corresponding to the guide pin by using the silicon optical bench, and even in the case of applying the monitor photodetector, it is possible to minimize the increase in manufacturing cost without complicating the optical module structure.

In addition, since the present invention uses a plastic mold lens for optical coupling between the optical element and the optical fiber, damage to the laser window or the bonding wire can be prevented, and the reflected light is used by tilting the main surface of the plastic mold lens even when the monitor photodetector is applied. Since it can be easily manufactured, the power of the back reflection light back to the optical device can be reduced, there is an advantage that can improve the optical properties. In addition, since the plastic mold lens prevents exposure of the optical device chip to the outside air, it is possible to prevent an operation error or aging of the optical module due to corrosion and oxidation.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

For example, in the above-described embodiment, the optical coupling between the optical fiber array and the array type optical device is described as an example. However, the technical idea of the present invention may be applied to optical coupling of a single optical fiber.

In addition, in the above-described embodiment, the case of applying to an optical transmitter module using VCSEL as an optoelectronic device has been described as an example. However, since the structure of the optical receiver module is similar, it may be applied to a receiver module using an optical detector as an optoelectronic device. have.

The present invention described above can reduce the manufacturing cost because the alignment and coupling structure of each component constituting the optical coupling module assembly is simple and employs a manual alignment structure that does not use expensive equipment. In addition, the present invention can simplify the optical coupling structure according to the application of the monitoring photodetector to achieve horizontal indirect coupling without increasing the manufacturing cost. In this case, since the reflective surface is used by tilting the main surface of the lens, a separate reflective coating thin film may not be used, and the power of the rear reflected light returned to the optical device may be reduced, thereby improving optical characteristics.

1 is a perspective view of a horizontal direct coupling structure of a VCSEL chip and an optical fiber according to the prior art.

2 is a cross-sectional view of a horizontal indirect coupling structure of a VCSEL chip and an optical fiber according to the prior art.

3 is a cross-sectional view of a vertical coupling structure of a VCSEL chip and an optical fiber according to the prior art.

4 is a block diagram of an optical coupling module assembly according to an embodiment of the present invention.

FIG. 5 is an alignment diagram of the silicon optical bench of FIG. 4 and the array VCSEL chip. FIG.

6 is an alignment diagram of a silicon optical bench and a plastic mold lens on which an array VCSEL chip is mounted.

7 is a conceptual diagram illustrating a beam path when light emitted from an array VCSEL chip travels through a plastic mold lens.

8 is a view showing a state in which the optical coupling sub-mount formed through the packaging process shown in Figures 5 and 6 mounted on a printed circuit board.

9 is an alignment diagram of an optical module including a monitoring photodetector.

10 is a conceptual diagram showing the shape of a plastic mold lens when a monitoring photodetector is included and a beam path when light emitted from the array VCSEL chip passes through the plastic mold lens.

* Explanation of symbols for main parts of the drawings

20: VCSEL chip (array)

30: silicon optical bench

31: V-groove for lens mounting

32: guide V-groove

34: solder

35 electrode

Claims (11)

Optical fiber cable connectors with built-in optical fiber; An adapter in which the optical fiber cable connector is plug-in, and in which a plurality of first alignment guide pins are embedded; A printed circuit board having a control circuit; A silicon optical bench mounted on the printed circuit board and having a plurality of first alignment V-grooves corresponding to the first alignment guide pins; An optoelectronic device mounted on the silicon optical bench; An optical coupling lens created on the silicon optical bench to cover the optoelectronic device; And Optical module package housing for protecting the printed circuit board Optical coupling module assembly having a. The method of claim 1, And a monitoring photodetector mounted on the same main surface on the silicon optical bench adjacent to the optoelectronic device. The method of claim 2, The optical coupling module assembly, characterized in that the one surface in contact with the optoelectronic device side inclined. The method according to claim 1 or 3, The optical coupling module assembly, characterized in that the optical coupling lens is a plastic mold lens. The method of claim 4, wherein The plastic mold lens is provided with a plurality of second alignment guide pins in the lower portion of the main surface in contact with the optoelectronic device side. The method of claim 5, And the silicon optical bench has a plurality of second alignment V-grooves corresponding to the second alignment guide pins. The method according to claim 1 or 2, And the optical fiber cable connector has a third alignment guide pin below the adapter, the optical module package housing, and the printed circuit board. The method according to claim 1 or 2, A bolt penetrating the adapter, the optical module package housing, and the printed circuit board; And a nut fastened to the lower portion of the printed circuit board corresponding to the bolt. The method of claim 6, The silicon optical bench, A first alignment mark and a first solder for chip bonding the optoelectronic device, And a second alignment mark and a second solder for chip bonding the monitoring photodetector. The method of claim 9, And said photoelectric device and said monitoring photodetector each have a solder pad and an alignment key on its back surface. In the method of packaging the optical coupling module assembly of claim 1, Coupling the optoelectronic device to the silicon optical bench using solder and bonding wires; Mounting the optical coupling lens on the silicon optical bench; Mounting the silicon optical bench on the printed circuit board using an epoxy; Fastening the optical fiber cable connector and the adapter in a plug-in manner; And Coupling the adapter coupled to the optical fiber cable connector to the printed circuit board on which the silicon optical bench is mounted using the first alignment guide pin and the first alignment V-groove. Packaging method of the optical coupling module assembly comprising a.