JP2004093742A - Multi-port optical module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-port optical module that can be manufactured at a low cost using conventional production equipment and members and also in a short development period of time. <P>SOLUTION: The multi-port optical module is composed of a package 2 in which two optical input/output ports 10 are provided on the opposing side faces and a cover 8 which hermetically seals the package 2. In addition, an optical input/output port 15 is installed on the cover 8 nearly vertically to the light propagating direction of the optical input/output ports 10 provided in the package 2. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multi-port optical module used for optical communication and measurement, which is a modularization of a light-light control type element that controls another optical signal with an optical signal, and an optical combining / branching that branches and combines optical signals. This is useful for circuit modularization.
[0002]
[Prior art]
4A and 4B show the structure of a conventional high-speed optical modulator module. FIG. 4A is a structural view from the top, and FIG. 4B is a structural view from the side.
To facilitate understanding of the internal structure, the left side of the center line is a sectional view, and the right side is an external view.
[0003]
FIG. 4 shows a high-speed optical modulator module 41 having an electro-absorption type semiconductor optical modulator (EAM) element 45 using the quantum confined Stark effect as an optical module having two light input / output ports. The high-speed optical modulator module 41 has a submount 44 for holding an EAM element 45 inside a box-shaped package 42 made of metal, and a package 42 via a Peltier cooler 43 for cooling the EAM element 45. It is attached to the bottom. The EAM element 45 has a small element size of several hundred μm square, and must have efficient optical coupling at both ends. Therefore, the submount 44 has an inverted T-shape as shown in FIG. 4, and the EAM element 45 is mounted on the protruding end of the central convex portion. In addition, a first lens 46 is provided on both sides of the convex portion near the EAM element 45, and is fixed to the submount 44 via a lens holder 47.
[0004]
The package 42 is sealed by welding a lid 48 for hermetic sealing from above. Optical input / output ports 50 for EAM are provided on both side surfaces of the package 42, and glass for airtight sealing is provided on the side surface of the package 42 on the optical input / output port 50 side for airtight sealing. A window 49 is provided. The optical input / output port 50 has a second lens 51 for optically coupling the EAM optical fiber 53 with the EAM element 45 inside the package 42, and the EAM optical fiber 53 is fixed by a ferrule collar 52.
[0005]
After being sealed by the lid 48, the high-speed optical modulator module 41 is assembled by optically aligning the second lens 51 and the optical fiber 53 through a glass window 49 for hermetic sealing on the side surface of the package 42, and then fixing them. ing. The use of two lenses for each optical input / output port 50 is to increase the production yield and to ensure the stability of optical coupling.
[0006]
A high-frequency wiring board 55 for controlling the EAM element 45 is provided inside the package 42, and an electric signal for controlling the EAM element 45 is transmitted to one of a plurality of electric terminals 54 provided on the other side of the package 42. The signal is applied from the high-frequency wiring board 55 to the EAM element 45 through the section.
[0007]
As shown in FIG. 4, conventionally, the driving of the optical modulator module has been controlled by adding an external electric signal to the optical modulator element inside the package. However, in order to transmit an ultra-high-speed electrical signal, it is difficult to achieve impedance matching, and in the case of an electrical signal exceeding 100 GHz, it becomes difficult to generate the electrical signal itself. There was a limit.
[0008]
In order to exceed the limit of the electric speed, a light-light control type element in which an optical modulator element is controlled by an optical signal has been developed. One example is a PD-EAM element in which a photodiode (PD) and an EAM are monolithically integrated.
[0009]
[Problems to be solved by the invention]
However, in order to use this PD-EAM element, three optical input / output ports are required, and it is extremely difficult to modularize the three optical input / output ports into one package.
[0010]
Specifically, it is necessary to fix each of the three optical input / output ports with respect to a small optical element by optically coupling them, and it is technically difficult to achieve efficient optical coupling of all the optical input / output ports. It is. In addition, in order to install the third optical input / output port on the side, the package is quite large and special, so an assembly device and an assembly jig for assembling it must be developed exclusively for it. And a large production cost is required.
[0011]
Due to the above problem, the characteristics of the optical modulator module using the PD-EAM element have been experimentally evaluated by using a hemispherical fiber or the like, but a practical module has not been developed yet. Not realized.
[0012]
On the other hand, other optical device modules requiring three or more multi-port optical input / output ports include a polarization combiner, a wavelength division multiplexing (WDM) multiplexer / demultiplexer, an optical multiplexer / demultiplexer, and the like. In these modules, a collimated optical system is often used, and unlike the optical coupling with the optical semiconductor element described above, the circuit size is large and the tolerance of optical coupling (tolerance) is relatively low. The technical difficulty is small, and it has been conventionally realized by a configuration in which three or more optical input / output ports are arranged on the side surface of the package.
[0013]
However, a package having three or more optical input / output ports is inevitably large in size. Therefore, each package is exclusively designed, and its holding method must be special. Therefore, assembling apparatuses and jigs are also basically dedicated, and it has been difficult to convert them to other types. For this reason, the cost must be increased unless the number of individual products is very large.
[0014]
Furthermore, it took a lot of time and cost to design and manufacture such a special package and adapt the manufacturing equipment to the package, so it was not possible to respond to an immediate specification change.
[0015]
The present invention has been made in view of the above problems, and has as its object to provide a multi-port optical module that can be manufactured at low cost and with a short development period by utilizing conventional manufacturing equipment and members.
[0016]
[Means for Solving the Problems]
The multiport optical module according to claim 1 of the present invention that solves the above problem has a package provided with at least two light input / output ports, and a lid that hermetically seals the package, At least one light input / output port is provided on the lid.
[0017]
According to another aspect of the present invention, there is provided a multi-port optical module including: a package provided on a side face facing two light input / output ports; and a lid for hermetically sealing the package. The at least one light input / output port is provided on the lid so as to be substantially perpendicular to the light propagation direction of the light input / output port provided on the package.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
FIGS. 1A and 1B show a structure of a multi-port optical module showing an example of an embodiment of the present invention. FIG. 1A is a structural view from the top, and FIG. 1B is a structural view from the side.
To facilitate understanding of the internal structure, the left side of the center line is a sectional view, and the right side is an external view.
[0019]
FIG. 1 shows an optical-optical control element module 1 using a PD-EAM element 5 as a multi-port optical module. The PD-EAM element 5 inputs and outputs an optical signal in a direction parallel to the element substrate in the EAM part, like the conventional EAM element, and inputs an optical signal in a direction perpendicular to the element substrate in the PD part.
[0020]
The light-light control element module 1 has a submount 4 for holding a PD-EAM element 5 inside a metal box-shaped package 2, and a Peltier cooler 3 for cooling the PD-EAM element 5. The package 2 is attached to the bottom of the package 2. The PD-EAM element 5 also has a small element size, and must have high-efficiency optical coupling at both ends. Therefore, the submount 4 has an inverted T-shape, and the PD-EAM element 5 is mounted on the protruding end of the central convex portion. A first lens 6 is provided on both sides of the convex portion close to the PD-EAM element 5, and is fixed to the submount 4 via a lens holder 7.
[0021]
EAM optical input / output ports 10 are provided on the side surfaces of the package 2, respectively. In the light-light control element module 1, the two optical input / output ports 10 face each other in the longitudinal direction of the package 2. It is provided in. A glass window 9 for hermetic sealing is provided on the inner surface side of the optical input / output port 10 of the package 2 for hermetic sealing of the package 2. The optical input / output port 10 has a second lens 11 for optically coupling the EAM optical fiber 13 with the PD-EAM element 5 inside the package 2, and the EAM optical fiber 13 is fixed by a ferrule collar 12. I have.
[0022]
The package 2 is sealed by welding a lid 8 for hermetic sealing from above. The lid 8 is also provided with a light input / output port 15 for PD as a light input / output port. To hermetically seal the package 2, a light input / output port 15 A glass window 9 for hermetic sealing is provided. The optical input / output port 15 has the same configuration as the optical input / output port 10, and has a PD lens 16 for optically coupling the PD optical fiber 18 with the PD-EAM element 5 inside the package 2. The optical fiber 18 is fixed by the ferrule collar 17. The light input / output port 15 is provided so as to be substantially perpendicular to the light propagation direction of the light input / output port 10 provided in the package 2.
[0023]
A plurality of electric terminals 14 are provided on the other side surface of the package 2. Has been supplied. By supplying an optical signal from the optical input / output port 15, the PD element inside the PD-EAM element 5 is controlled, and a signal for controlling the EAM element inside the PD-EAM element 5 is supplied from the PD element. I have.
[0024]
The assembly of the light-light control element module 1 is performed in exactly the same procedure and apparatus as before until the EAM optical fiber 13 is fixed. That is, after the PD-EAM element 5, the first lens 6, and the like are mounted inside the package 2, the package is sealed with the lid 8, and then the second lens 11 is connected to the second lens 11 through the hermetic sealing glass window 9 on the side surface of the package 2. The optical fibers 13 are optically aligned and assembled. The reason why two lenses are used for each optical input / output port 10 is to increase the production yield and to ensure the stability of optical coupling.
[0025]
The package 2 is the same as the package 42 (see FIG. 4) for the conventional high-speed optical modulator module 41 using the EAM element 45. Therefore, assembling and adjustment can be performed by the same procedure and apparatus as in the related art, and the same precision as in the related art can be secured for the fixing accuracy of the second lens 11 and the EAM optical fiber 13 at the EAM optical input / output port 10. If this assembling procedure is changed to a procedure of fixing the lid 8 after fixing the EAM optical fiber 13, the optical axis tolerance of the PD-EAM element 5 with respect to the EAM optical input / output port 10 is extremely strict. When fixing the lid 8, the optical axis may be shifted, and the yield may be deteriorated. Further, the lid 8 must be designed so as not to protrude outside so that it can be used in a conventional device.
[0026]
Finally, the PD optical input / output port 15 is joined using a dedicated assembly jig or device. At this time, the optical axes of the PD lens 16 and the PD optical fiber 18 are adjusted while measuring the light receiving current of the PD portion inside the PD-EAM element 5, and are sequentially fixed to complete the assembly. The optical axis tolerance of the optical coupling of the PD lens 16 and the PD optical fiber 18 of the PD optical input / output port 15 is the optical coupling tolerance of the EAM lens 11 and the EAM optical fiber 13 of the EAM optical input / output port 10. Since it is much slower than the shaft tolerance, it does not require very precise equipment for assembly, and can be dealt with by relatively inexpensive equipment or changing jigs.
[0027]
In order to fix a lens, a fiber or the like, YAG laser welding is generally used recently from the viewpoint of strength, stability and productivity, and the welding depth of the YAG laser at that time is usually 200 to 400 μm. Therefore, the thickness of the lid 8 is desirably 0.5 mm or more.
[0028]
In addition, since the material of the lid 8 is generally made of an iron-nickel alloy having a linear expansion coefficient close to that of alumina, the lid 8 is also made of an iron-nickel alloy having the same linear expansion coefficient. Or if it is necessary to dissipate heat especially from the lid 8, a copper-tungsten or molybdenum-based alloy having a coefficient of linear expansion close to that of an iron-nickel-based alloy and having a high thermal conductivity can also be used. .
[0029]
In the case of an optical module in which the operating conditions and the optical axis tolerance are not strict, a less expensive stainless steel alloy suffices although the coefficient of linear expansion is slightly larger.
[0030]
FIG. 2 is a layout diagram showing an example of mounting a multi-port optical module on a substrate according to the present invention.
[0031]
Since the light-light control element module 1 shown in FIG. 1 has the light input / output port 15 protruding from the lid 8, it is considered difficult to mount the light-light control element module 1 on the printed circuit board 19, which is a realistic method for mounting an optical module. . However, as shown in FIG. 2, the light-light control element module 1 is attached to the L angle 21, and the EAM optical fiber 13 and the PD optical fiber 18 are mounted so as to be parallel to the printed circuit board 19. Solvable. By mounting the light-light control element module 1 on the printed circuit board 19, the electric terminals 14 of the light-light control element module 1 can be wired to the printed circuit board 19 using the solder 20. Further, by fixing the L angle 21 using the screw 22, the light-light control element module 1 can be firmly fixed to the printed circuit board 19. By devising the shape of the L-angle 21, it can also be used as a heat-radiating fin of the light-light control element module 1.
[0032]
FIG. 3 is a side view of a multi-port optical module showing another example of the embodiment of the present invention.
To facilitate understanding of the internal structure, the left side of the center line is a sectional view, and the right side is an external view.
[0033]
FIG. 3 shows an optical multiplexing / branching circuit module 30 having an optical multiplexing / branching circuit (optical Add-drop circuit) for separating / combining a part of an optical signal as a multi-port optical module.
[0034]
The optical coupling / branching circuit module 30 has a plurality (two in FIG. 3) of beam splitters 33 for separating / combining a part of an optical signal inside a metal box-shaped package 31. It is attached to the bottom of the package 31 via a holding submount 32. The beam splitters 33 are arranged on the same optical axis in the longitudinal direction inside the package 31, and further, inside the package 31 on both side ends thereof, a collimating lens 37 held by a lens holder 36 is provided. Is provided.
[0035]
Optical input / output ports 38a are provided on the side surfaces of the package 31, respectively. In the optical coupling / branching circuit module 30, two optical input / output ports 38a are provided so as to face each other in the longitudinal direction of the package 31. . In the optical input / output port 38a, the optical fiber 40 is fixed by a ferrule collar 39. The optical signal from the optical fiber 40 is converged on the beam splitter 33 by the collimator lens 37.
[0036]
The package 31 is sealed by welding a lid 34 for hermetic sealing from above. The lid 34 is also provided with a plurality of (two in FIG. 3) light input / output ports 38b as light input / output ports, and the inner surface of the light input / output port 38b of the cover 34 for hermetic sealing of the package 31. On the side, a glass window 35 for hermetic sealing is provided. The optical input / output port 38b has a collimator lens 37 for optically coupling the optical fiber 40 with the beam splitter 33 inside the package 31. The optical fiber 40 is fixed by a ferrule collar 39.
[0037]
Since the required number of light multiplexing / branching varies depending on the place where it is used, in the conventional optical multiplexing / branching circuit module, it is necessary to manufacture a package for each branching number and assemble it as an optical module. However, when using the multi-port optical module according to the present invention, it is possible to easily cope with an increase or decrease in the number of ports by changing only the lid 34 according to the number of branches. Therefore, it is possible to share the basic package, to greatly reduce the cost, and to quickly respond to a specification change.
[0038]
What should be noted here is the difference between the linear expansion coefficients of the lid 34 and the package 31. For example, when the number of branches is very large and the maximum distance between the facing ports is 50 mm, the difference in linear expansion coefficient is about 10 ppm / ° C. (for example, the package of the iron-nickel-cobalt alloy and the lid of SUS304). If such a combination exists, 100 ° C. is required as a temperature guarantee range of a general optical component, so that the change in the distance between the ports becomes 100 μm at the maximum. Therefore, in such a case, it is basically necessary to select the same material.
[0039]
【The invention's effect】
As described above, according to the first or second aspect of the present invention, there is provided a package provided with at least two light input / output ports, and a lid for hermetically sealing the package, Since at least one light input / output port is provided on the lid, an optical element module having a multiport light input / output port can be realized at low cost using conventional manufacturing equipment. Further, the present invention can be widely applied to an optical device having multiple ports, and can be applied to an optical switch, an optical multiplexer / demultiplexer, an optical delay circuit, and the like in addition to the embodiment. Further, the optical port is not limited to the fiber output, and it is also possible to directly mount and couple a PD or LD / LED. The present invention is particularly effective for the production of small lots and many kinds of products such as custom-made products and prototypes, and can be economically produced with good productivity by using conventional production equipment.
[Brief description of the drawings]
FIGS. 1A and 1B show a structure of a multi-port optical module showing an example of an embodiment of the present invention, wherein FIG. 1A is a structural view from the top, and FIG.
FIG. 2 is a layout view showing an example of mounting a multi-port optical module on a substrate according to the present invention.
FIG. 3 is a structural view from the side of a multi-port optical module showing another example of the embodiment of the present invention.
4A and 4B show the structure of a conventional high-speed optical modulator module, wherein FIG. 4A is a structural view from the top, and FIG. 4B is a structural view from the side.
[Explanation of symbols]
Reference Signs List 1 light-light control element module 2 package 3 Peltier cooler 4 submount 5 PD-EAM element 6 first lens 7 lens holder 8 lid 9 glass window for hermetic sealing 10 light input / output port for EAM 11 second lens 12 ferrule color 13 EAM optical fiber 14 Electrical terminal 15 PD optical input / output port 16 PD lens 17 Ferrule color 18 PD optical fiber

Claims (2)

A package provided with at least two light input / output ports,
A lid for hermetically sealing the package,
Furthermore, at least one light input / output port is provided on the lid, and the multiport optical module is characterized in that: A package provided on a side face facing two light input / output ports,
A lid for hermetically sealing the package,
A multi-port provided on the lid such that at least one light input / output port is substantially perpendicular to a light propagation direction of the light input / output port provided on the package. Optical module.

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