JP2014085639A - Wavelength division multiplex optical transmitter module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength division multiplex optical transmitter module capable of transmitting signal light emitted from a plurality of light sources in a wavelength-multiplexed manner with high optical coupling efficiency and fixing a lense for each light source at a desired position with high accuracy.SOLUTION: A wavelength division multiplex optical transmitter module performs wavelength-division multiplexing and relaying a signal light from a plurality of light sources mounted on a mounting substrate by optical components including a plurality of optical lenses 8a to 8d which are resin-fixed to a position corresponding to each of the plurality of light sources on the mounting substrate. Each of the plurality of optical lenses 8a to 8d has a notch part 81 for restraining the spread of resin on the resin adhesive surface toward the mounting substrate.

Description

  The present invention relates to a wavelength-multiplexed optical transmission module that transmits wavelength-multiplexed signal light.

The wavelength multiplexing optical transmission module transmits signal light emitted from a plurality of light sources by wavelength multiplexing using optical system components such as an optical lens, a wavelength selection filter, and a reflection mirror. The component is resin-fixed on the mounting board.
Patent Document 1 discloses a wavelength division multiplexing optical transmission module in which light sources and optical lenses are arrayed.

JP 2011-663339 A

When an array lens is used as in the wavelength division multiplexing optical transmission module of Patent Document 1, the position of each lens portion of the array lens with respect to the light source cannot be accurately determined, so that high optical coupling efficiency cannot be obtained.
On the other hand, when each lens is a separate body instead of the array lens, there are the following problems. That is, in the wavelength division multiplexing optical transmission module, a plurality of light sources are mounted so as to be in one row, and in accordance with this, the lenses for each light source are fixed in resin so that they are also in one row. Since the module package is small and the distance between the lenses is short, the resin fixing adhesive used for each lens interferes with each other, and the lens cannot be fixed at a desired position with high accuracy.

  The present invention has been made in view of the above circumstances, and can multiplex signal light emitted from a plurality of light sources and transmit them with high optical coupling efficiency. It is an object of the present invention to provide a wavelength division multiplexing optical transmission module that can be fixed at a desired position and a manufacturing method thereof.

  The wavelength division multiplexing transmission module of the present invention includes an optical component including a plurality of optical lenses for fixing signal light from a plurality of light sources mounted on a mounting substrate to positions corresponding to the plurality of light sources on the mounting substrate, respectively. Each of the plurality of optical lenses has a cut-out portion that suppresses the spread of the resin on the resin bonding surface to the mounting substrate.

In addition, the notch part is provided on the side of the resin bonding surface, for example, and the shape is notched into a right triangular prism shape. Specifically, the notches are provided on both sides of the resin-bonded surface orthogonal to the optical axis direction of the optical lens and / or on both sides parallel to the optical axis direction. In addition, the cutout portion may have a shape in which a corner portion of the resin bonding surface is cut out in a right triangular pyramid shape.
The resin adhesive for fixing the optical lens with a resin is preferably an ultraviolet curable resin adhesive having a thixo value of 1.0 or more.

  Since the wavelength division multiplexing transmission module of the present invention is not an array lens but separate lenses, and can be individually positioned, wavelength multiplexed signal light can be transmitted with high optical coupling efficiency. In addition, among optical system components including lenses, at least the adhesive surface to the mounting substrate of the lens has a notch that suppresses the spread of the resin adhesive, so that the resin adhesives for fixing each lens interfere with each other. Each lens can be fixed at a desired location with high accuracy.

It is the figure which showed typically an example of the wavelength division multiplexing optical transmission module of this invention. It is the figure which showed the optical lens of the wavelength division multiplexing optical transmission module of FIG. It is the figure which showed the mounting substrate of the wavelength division multiplexing optical transmission module of FIG. It is the figure which showed typically the other example of the wavelength division multiplexing optical transmission module of this invention. It is a figure which shows the other example of an optical lens. It is a figure which shows another example of an optical lens. It is a figure which shows another example of an optical lens.

FIG. 1 is a diagram schematically showing an example of a wavelength division multiplexing optical transmission module of the present invention.
The wavelength division multiplexing optical transmission module 1 shown in the figure includes a main body 2 that wavelength-multiplexes and transmits signal light, and a sleeve component 3 that guides the wavelength-multiplexed signal light to an optical transmission line.
The main body 2 has a housing 6 composed of a package 4 and a lid 5. Although illustration is omitted, an opening is provided in front of the package 4 (on the sleeve part 3 side), and a sealing glass is provided in the opening, which serves as a window for signal light.

The main body 2 includes a plurality of light sources 7 a to 7 d that emit signal light and various optical system components in the housing 6. Here, the optical system components include a plurality of optical lenses 8a to 8d, polarization rotation components 9a and 9b, wavelength selection filters 10a and 10b, polarization selection filter 11, and reflection mirrors 12a to 12c.
The main body 2 includes a light source driving component 13 for driving a plurality of light sources 7a to 7d and a mounting substrate 14 on which the plurality of light sources 7a to 7d and various optical system components are fixed with resin. And having.

  The plurality of light sources 7a to 7d are arranged in a line and generate light having different wavelengths, for example, generate light having wavelengths λ1, λ2, λ3, and λ4, respectively. As the wavelengths λ1, λ2, λ3, and λ4, the oscillation wavelengths according to the LAN-WDM standard are selected. For example, the center wavelengths are 129.56 nm, 130.56 nm, 130.05 nm, 1304.58 nm, and 1309.14 nm, respectively. is there.

The optical lenses 8a to 8d are provided at corresponding positions of the light sources 7a to 7d, and convert light from the corresponding light sources 8a to 8d into collimated light. In the following, it is assumed that the optical lenses 8a to 8d have the same shape.
The polarization rotation components 9a and 9b are provided in front of the first and third light sources 7a and 7c from the shorter wavelength, and provide output light obtained by rotating the polarization plane of incident light by 90 degrees.

The wavelength selection filter 10a is provided in front of the polarization rotation component 9a, and its optical characteristic selectively transmits light having a wavelength λ1 and reflects light having a wavelength λ3.
The wavelength selection filter 10b is provided in front of the optical lens 8b, and selectively transmits light having the wavelength λ2 and reflects light having the wavelength λ4.

  The polarization selection filter 11 is provided in front of the wavelength selection filter 10a, and its optical characteristics are polarized light after emission from the polarization rotation component 9a at the wavelength λ1 and emission from the polarization rotation component 9b at the polarization λ3. And the light having a polarization plane with an angle (for example, 90 degrees) different from that of the above polarized light at the wavelength λ2 or λ3.

  The reflection mirror 12a is provided in front of the wavelength selection filter 10a, and has an optical characteristic that reflects light having a wavelength λ2. The reflection mirror 12b is provided in front of the polarization rotation component 9b, and reflects the light having an optical characteristic of wavelength λ3. The reflection mirror 12c is provided in front of the optical lens 8d, and reflects the light whose wavelength is λ4.

  In the wavelength division multiplexing optical transmission module 1, the signal light emitted from the plurality of light sources 7 a to 7 d in the main body 2 is wavelength-multiplexed by the optical system components such as the optical lenses 8 a to 8 d described above, and provided in the housing of the main body 2. From the window. The emitted wavelength multiplexed signal light is collected by the optical lens 31, passes through the polarization-independent isolator 32, and is optically coupled to the optical fiber 33.

  The light driving component 13 for driving the light sources 7a to 7d is directly fixed to the package 4, whereas the mounting substrate 14 to which the light sources 7a to 7d are fixed with resin is a countermeasure against heat generated from the light sources 7a to 7d. Therefore, it is fixed to the package 4 via a heat dissipation component (not shown) made of a Peltier element or the like.

  The wavelength division multiplexing optical transmission module 1 having the above-described configuration is characterized by the shapes of the optical lenses 8a to 8d for resin-fixing to the mounting substrate 14, and the characteristics will be described below with reference to FIG. 2 is a diagram showing only the optical lens 8a of the wavelength division multiplexing optical transmission module 1 in FIG. 1, FIG. 2 (A) is a perspective view, FIG. 2 (B) is a side view in the front-rear direction, that is, the optical axis direction, FIG. 2C is a side view perpendicular to the optical axis direction and parallel to the mounting surface of the mounting substrate 14.

As shown in FIGS. 2A to 2C, the optical lens 8a has a substantially rectangular parallelepiped shape, and the side of the resin adhesion surface (bottom surface in the figure) to the mounting substrate 14 is specifically the optical axis direction. Both sides perpendicular to each other have a shape cut out in a right isosceles triangular prism shape, in other words, have a cutout portion 81 along both sides perpendicular to the optical axis direction of the bonding surface.
Since the notch 81 is formed in this way, it is possible to suppress the seepage of the resin adhesive to the adjacent optical lens 8b when the optical lens 8a is fixed with resin.
As described above, the optical lenses 8b to 8d have the same shape as the optical lens 8b. Therefore, the resin adhesives for fixing the lenses 8a to 8d do not interfere with each other, and the lenses 8a to 8d can be fixed to desired locations with high accuracy.

In addition, since the resin adhesive enters the notch 81 as described above, a high adhesive force is generated between the optical lens 8a and the mounting substrate 14, and as a result, high shear strength for the optical lens 8a is obtained. be able to. The same applies to the optical lenses 8b to 8d.
For example, when the optical lens has a width of 1.1 mm and a thickness of 0.6 mm, the notch 81 has a depth of about 50 μm.

  Further, as the resin adhesive, a thixotropic adhesive is used because shape stability is necessary (after application) so as not to spread after application to the mounting substrate 14. Specifically, it is preferable to use an adhesive having a thixo value greater than 1.0 obtained from a ratio of 50 Rpm and 5 Rpm with a rotational viscometer. As such an adhesive, a resin adhesive containing a certain amount of fine particles of 10 to 50 μm formed from one or more of calcium carbonate, quartz, alumina and the like can be considered. Further, from the viewpoint of high-precision resin fixation, an ultraviolet curable epoxy resin adhesive having a small curing shrinkage rate during ultraviolet curing or the like is preferable.

Next, with reference to FIG. 1 and FIG. 2, a method for manufacturing the wavelength division multiplexing optical transmission module of the present invention will be described with reference to FIG. FIG. 3 is a diagram showing only the mounting substrate 14 of the wavelength division multiplexing optical transmission module 1 of FIG.
Prior to the description of the method for manufacturing the wavelength division multiplexing optical transmission module 1, the mounting substrate 14 will be described. As shown in FIG. 3, the mounting substrate 14 has, for example, a positioning mark 14b for positioning the light sources 7a to 7d, a positioning mark 14c for positioning the wavelength selection filters 10a and 10b, and a polarization on the mounting surface 14a. A positioning mark 14d for positioning the selection filter 11 is provided. As the base material of the mounting substrate 14, an aluminum nitride substrate, a silicon (Si) substrate, a quartz (SiO2) substrate, an iron nickel cobalt alloy substrate, or a substrate obtained by performing gold plating on the alloy substrate can be used.

  When the wavelength division multiplexing optical transmission module 1 is manufactured, first, the light sources 7a to 7d are placed on the positioning marks 14b on the mounting substrate 14 as described above and fixed with solder or the like. Then, a predetermined amount of resin adhesive is applied to the mounting region of the optical lens 8 a of the mounting substrate 14. Thereafter, in a state where a probe or the like is brought into contact with the light source 7a and a weak current is passed, the optical lens 8a is gripped by using an alignment equipment, and the position of the optical lens 8a is adjusted on the resin adhesive in all the XYZ directions. At this time, the light emitted from the optical lens 8a is monitored by a general-purpose beam profiler, and the optical lens 8a is adjusted to a position where desired parallel light can be obtained as the emitted light. After the position adjustment, a predetermined amount of ultraviolet light is irradiated to temporarily fix the optical lens 8a. The same operation is repeated for the optical lenses 8b to 8d.

Next, the polarization rotation components 9a and 9c are temporarily fixed in front of the light sources 7a and 7c. This temporary fixing is performed using an ultraviolet curable resin adhesive or a thermosetting resin adhesive based on a positioning mark (not shown) on the mounting substrate 14.
Similarly, the wavelength selection filters 10 a and 10 b and the polarization selection filter 11 are temporarily fixed using a resin adhesive based on the positioning marks 14 c and 14 d on the mounting substrate 14.

  Then, as described above, the mounting substrate 14 on which the light sources 7 a to 7 d and the optical lenses 8 a to 8 d are temporarily fixed is fixed to the package 4. This fixing is performed at a position where the light receiving sensitivity of the monitor device attached to the opening with the sealing glass provided in front of the package 4 is maximized. Note that the monitor device is a device including a single mode fiber with a collimating lens fixed to another stage. The light source driving component 13 is fixed to the package 4 with solder or the like in advance, and after the mounting substrate 14 is fixed, wiring between the light sources 7a to 7d and the light source driving component 13 is performed and electrically connected.

Next, the reflecting mirrors 12a to 12c are temporarily fixed. This temporary fixing is performed by using a resin adhesive at each of the reflection mirrors 12a to 12c at an angle and a position where the light receiving sensitivity by the above-described monitor device is maximized.
After all the above-described temporary fixing is completed, each part is permanently fixed using heat.
Thereafter, the lid 5 is welded to the package 4 in a nitrogen atmosphere, and the light sources 7a to 7d and each optical system component are hermetically sealed.

Finally, the sleeve part 3 is aligned and fixed to the package 4 by YAG welding. The alignment of the sleeve component 3 is performed by causing the light source 7a to emit light and adjusting the position of the sleeve component 3 to a position where the maximum amount of light received by the optical fiber 34 of the sleeve component 3 is obtained.
The wavelength multiplexing transmission module 1 is completed through the above steps.

  The above-described manufacturing procedure is an example, and after mounting optical system components other than the reflection mirrors 12a to 12c on the mounting substrate, the light source is aligned while checking the beam shape with a general-purpose beam profiler. Good.

  In the above example, only the optical lenses 8a to 8d among the optical system parts are notched in the bonding surface, but other optical system parts such as the reflection mirrors 12a to 12c are also around the mounting region. You may make it form a groove | channel in this.

FIG. 4 is a diagram schematically showing another example of the wavelength division multiplexing optical transmission module of the present invention. In addition, about the structure similar to the wavelength division multiplexing optical transmission module 1 of FIG. 1, the description is abbreviate | omitted by attaching | subjecting the same referential mark.
In the wavelength division multiplexing optical transmission module 1 of FIG. 1, an optical system is formed using the polarization rotation components 9a and 9b, the wavelength selection filters 10a and 10b, the polarization selection filter 11, and the like, and the lights from λ1 to λ4 are multiplexed. On the other hand, the wavelength division multiplexing optical transmission module 1 ′ shown in FIG. 4 collects four lights on the condenser lens 31 of the sleeve part 3 using a PLC (planar optical waveguide) 15.

  Even when the wavelength division multiplexing optical transmission module 1 ′ is manufactured, in order to extract the light from λ1 to λ4 as collimated light (parallel light), until the optical lenses 8a to 8d are fixed in front of the light sources of the respective wavelengths. The same method as that in the wavelength division multiplexing module 1 of FIG. 1 can be adopted. After fixing the optical lens, the PLC 15 is fixed to a predetermined substrate inside the package with solder or silver paste. In addition, as a fixing method of PLC15, for example, after performing alignment using a predetermined facility so that the optical coupling efficiency with respect to the optical fiber becomes the highest, a method of performing resin fixing using an ultraviolet thermosetting adhesive is used. By adopting it, it is possible to produce a wavelength division multiplexing optical transmission module with a small optical coupling loss.

Note that the shapes of the optical lenses 8a to 8d are not limited to the shapes described above.
5 to 7 are diagrams showing other examples of the optical lens. FIGS. 5 (A), 6 (A), and 7 (A) are perspective views, and FIG. 5 (B) and FIG. B) and FIG. 7B are side views in the front-rear direction, that is, the optical axis direction, and FIGS. 5C, 6C, and 7C are directions perpendicular to the optical axis direction of the mounting substrate 14. It is a side view of a mounting surface and a parallel direction. In each example, one of the plurality of optical lenses used in the wavelength division multiplex transmission module of the present invention is illustrated, but the other optical lenses are assumed to have the same shape.

  The optical lens 41a in FIGS. 5A to 5C has a substantially rectangular parallelepiped shape, and both sides in the direction parallel to the optical axis direction of the resin bonding surface (bottom surface in the figure) to the mounting substrate 14 are a right isosceles triangular prism shape. In other words, it has a notch portion 410 along both sides of the bonding surface in the direction parallel to the optical axis direction.

  The optical lens 51a in FIGS. 6A to 6C has a substantially rectangular parallelepiped shape, and is parallel to the both sides in the direction orthogonal to the optical axis direction of the resin bonding surface (bottom surface) to the mounting substrate 14 and the optical axis direction. Both sides have a shape that is cut out into a right-angled isosceles triangular prism shape, in other words, cut out along both sides in a direction perpendicular to the optical axis direction of the adhesive surface and both sides in a direction parallel to the optical axis direction. Part 510.

  The optical lens 61a shown in FIGS. 7A to 7C has a substantially rectangular parallelepiped shape, and corners, more specifically, four corners, of the adhesion surface (bottom surface) to the mounting substrate 14 are right-angled isosceles triangles. In other words, it has notches 510 at the four corners on the bonding surface side.

  In the above example, the plurality of optical lenses used for the wavelength division multiplexing transmission module of the present invention have the same shape, but may have different shapes.

DESCRIPTION OF SYMBOLS 1 ... Wavelength division multiplexing optical transmission module, 2 ... Main-body part, 3 ... Sleeve part, 4 ... Package, 5 ... Cover, 6 ... Housing, 7a-7d ... Light source, 8a-8d, 41a-41d, 51a-51d, 61a- 61d: Optical lens, 9a, 9b: Polarization rotating component, 10a, 10b: Wavelength selection filter, 11: Polarization selection filter, 12a-12c: Reflection mirror, 13: Light source driving component, 14: Mounting substrate, 15: Plane Optical waveguide.

Claims (5)

Signal light from a plurality of light sources mounted on a mounting board is wavelength-multiplexed by an optical component including a plurality of optical lenses fixed to a position corresponding to each of the plurality of light sources on the mounting board and transmitted. In the wavelength division multiplexing optical transmission module,
Each of the plurality of optical lenses has a notch portion that suppresses the spread of the resin on the resin adhesion surface to the mounting substrate.   2. The wavelength division multiplexing optical transmission module according to claim 1, wherein the cutout portion is provided on a side of the resin bonding surface and has a shape cut out in a right triangular prism shape.   3. The wavelength division multiplexing according to claim 2, wherein the notch portions are provided on both sides of the resin adhesion surface orthogonal to the optical axis direction of the optical lens and / or both sides parallel to the optical axis direction. Optical transmission module.   2. The wavelength division multiplexing optical transmission module according to claim 1, wherein the notch has a shape in which a corner of the resin bonding surface is notched in a triangular pyramid shape. The wavelength according to any one of claims 1 to 4, wherein the resin adhesive for fixing the optical lens with resin is an ultraviolet curable resin adhesive having a thixo value of 1.0 or more. Multiplex optical transmission module.

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