JP2004200331A - Optical communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical communication device having improved high-frequency characteristics by adopting a package for reducing a transmission loss at a signal input. <P>SOLUTION: The optical communication device comprises a package case made of plastic having an opening; a plurality of leads extended inside and outside the package, a lead base that is arranged at the inner bottom of the opening of the package and is partially connected to the lead; a support substrate that is fixed onto the lead base and has a conductive pattern on the upper surface; light elements (LD, PD) fixed onto the support substrate; an optical fiber that is mounted to a package in a penetration state for sending and receiving light to and from the LD; one or a plurality of electronic components arranged in the package; and a conductive wire for electrically connecting the electrode of the light element, that of the electronic components, the conductive layer of the support substrate, and the lead as needed, thus composing a coplanar transmission line that is impedance-matched by a signal lead for composing a high-frequency signal input section, ground leads at both the sides, and plastic for forming the package case. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical communication device, and particularly to a technology that is effective when applied to a manufacturing technology of an optical communication module for transmission or reception in optical communication.
[0002]
[Prior art]
Semiconductor lasers (laser diodes) are used as light sources for information processing devices and optical communication devices. In optical communication, optoelectronic devices such as a transmitting optical communication module and a receiving optical communication module are used. For example, Japanese Patent Application Laid-Open No. 10-307235 discloses a semiconductor laser module for transmission and a manufacturing technique thereof. This document discloses a semiconductor laser module in which a laser diode, a photodiode, and an optical fiber are mounted on a main surface of a silicon substrate fixed to an inner bottom surface of a package case (so-called passive alignment mounting), and the package case is sealed with a cap. Is described. The package case is formed by molding (molding) a plastic, and integrally forming an optical fiber installation groove and an optical fiber coating portion installation groove on the side of the package case with the pad portion with the lead terminal.
[0003]
Further, as a similar type of configuration, there is an optical communication module having a ceramic package structure in which a package has a hermetically sealed structure. As an optical communication module having this type of ceramic package structure, for example, Lucent Technologies, published by microelectronicsgroup, data sheet A laser module as described in DSO1-020OPTO (Replaces DS99-023LWP), December issue, 2000, P1 to P8 is known.
[0004]
[Problems to be solved by the invention]
The amount of data on the Internet (traffic), especially traffic flowing to the US mains, is increasing at a phenomenal pace. The development of high-speed and long-distance (for example, 10 Gbps, 80 km) transmission devices connecting large cities and within cities is proceeding at a rapid pace. On the other hand, there is also a demand for faster transmission devices such as an intra-office interface and a LAN connected to those transmission devices, which connect a short distance of 2 km or less.
[0005]
For widespread use of optical communication devices, cost reduction is an issue, and high-speed transmission devices of the 10 Gbps class are no longer an exception. A method of manufacturing a plastic package case by transfer molding using a lead frame is effective in reducing the cost of an optical communication device.
[0006]
Therefore, the present inventors have analyzed and studied an optical communication device using a plastic package case. As a result, the following facts were confirmed.
[0007]
It has been found that the prior art has a large lead and wire inductance and is not necessarily suitable for high-speed transmission. That is, the leads incorporated in the package case extend along the bottom of the package case and protrude outside the package case inside the package case, and bend and extend stepwise outside the package case at the tip outside the package case. The structure has a mounting portion suitable for surface mounting. As a result, the lead becomes longer and the inductance of the lead becomes larger.
[0008]
The leads and the lead base are formed by patterning a single flat metal plate. A support substrate is fixed on the lead base, and a semiconductor laser device and a resistor connected to the semiconductor laser device are fixed on the support substrate. One electrode of the resistor is connected to a lead via a wire. Therefore, the electrode surface of the resistor to which the wire is connected, that is, the wire connection surface of the resistor, is higher than the wire connection surface of the lead by the thickness of the support substrate and the semiconductor laser element. As a result, the length of the wire connecting the two points having different heights is increased by the difference in height, and the inductance of the wire is increased.
[0009]
An object of the present invention is to provide an optical communication device having excellent high frequency characteristics.
[0010]
Another object of the present invention is to provide an optical communication device having a small propagation loss.
[0011]
Another object of the present invention is to provide an optical communication device having a low inductance value that is impedance-matched.
[0012]
Another object of the present invention is to provide an optical communication device that can be reduced in cost.
[0013]
The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.
[0014]
[Means for Solving the Problems]
The outline of a typical invention among the inventions disclosed in the present application will be briefly described as follows.
[0015]
(1) a package case made of plastic and having an opening on an upper surface;
A cap for closing the upper surface of the package case,
A plurality of metal leads that extend over the inside and outside of the package case and serve as electrode terminals,
A lead base disposed on the inner bottom of the package case and integrally formed with at least one or a plurality of the leads;
A support substrate fixed on the lead base and having a conductor pattern of a predetermined pattern on the upper surface,
One or more optical elements fixed on the support substrate,
The package case extends over the inside and outside of the package case, and has an inner end facing the one optical element (semiconductor laser element) so as to transmit and receive light to and from the semiconductor laser element. An optical fiber to be fixed;
One or more electronic components fixed to leads including the lead base in the package case;
An optical communication device comprising: a conductive wire that electrically connects each of the electrode of the optical element, the electrode of the electronic component, the conductive layer of the support substrate, and the lead as necessary,
Among the leads, the signal lead constituting the high-frequency signal input unit is arranged such that ground leads serving as ground electrodes are disposed on both sides thereof at predetermined intervals, and the signal lead and the ground leads on both sides and the signal lead and the ground lead are connected to each other. A coplanar transmission line whose impedance is matched by the package case portion to be supported is configured.
[0016]
The lead includes a flat surface portion located at the opening and connected to the wire, an inclined surface portion connected to the flat surface portion, and a mounting portion connected to the inclined surface portion and having a tip portion protruding from the package case. In the lead serving as a high-frequency signal input unit of the optical element (semiconductor laser element), the inclined surface portion is longer than other leads, the height of the flat surface portion is higher than the lead base surface, and the height of the flat surface portion is higher. The wire connection surface and the wire connection surface at the other end of the wire connected to the wire connection surface are at the same height or close to each other.
[0017]
According to the means of (1), (a) since a coplanar transmission line with impedance matching is formed inside the package case, propagation loss in a lead constituting the high-frequency signal input section can be reduced, and the high-frequency of the optical communication apparatus can be reduced. The characteristics are improved.
[0018]
(B) Since the lead comprises a flat surface portion, an inclined surface portion connected to the flat surface portion, and a mounting portion connected to the inclined surface portion, the length of the lead can be shortened, the inductance of the lead can be reduced, and the optical communication device can be reduced. The high frequency characteristics of are improved.
[0019]
(C) The lead serving as the high-frequency signal input portion of the semiconductor laser element has an inclined surface longer than the other leads, a flat surface higher than the lead base surface, and a flat surface connected to the wire. Since the wire connection surface at the other end of the wire connected to the surface is at the same height or close to the height, the length of the wire can be shortened, the inductance of the wire can be reduced, and the high frequency characteristics of the optical communication device Is improved.
[0020]
(D) According to the above (a) to (c), it is possible to provide an optical communication device having good high frequency characteristics from impedance matching and inductance reduction.
[0021]
(E) Since a coplanar transmission line is formed by a plastic package configuration and a plastic package case and leads, cost reduction of the optical communication device can be achieved.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings for describing the embodiments of the present invention, components having the same functions are denoted by the same reference numerals, and their repeated description will be omitted.
[0023]
(Embodiment 1)
1 to 11 are diagrams related to an optical communication module for transmission (optical communication device) according to an embodiment (Embodiment 1) of the present invention. 1 to 6 are diagrams relating to the structure of the transmission optical communication module, FIG. 7 is an equivalent circuit diagram of the transmission optical communication module, FIGS. 8 and 9 are diagrams relating to the manufacture of the transmission optical communication module, FIGS. FIG. 11 is a diagram related to the mounting state of the optical communication module for transmission.
[0024]
In the first embodiment, an example in which the present invention is applied to a 10 Gb / s transmission optical communication module will be described. As shown in FIGS. 1 and 5, the transmission optical communication module 10 of the first embodiment includes a package case 11 and a cap 12 that is stacked so as to cover the package case 11 and fixed by a bonding material. A package (sealing body) 13 is formed. The package case 11 and the cap 12 are both made of plastic. The plastic is made of, for example, wholly aromatic polyester. The package case 11 and the cap 12 have substantially the same outer shape.
[0025]
The package case 11 and the cap 12 each include a rectangular main body 11a, 12a and guides 11b, 12b protruding from the center of one end of the main body 11a, 12a (see FIGS. 1 and 2). ). The main body 11a of the package case 11 has a box-shaped structure with an opening at the top (opening 11c). Grooves 14a and 14b are provided at the center of the portion from the guide portion 11b to the opening of the main body portion 11a so as to guide the optical fiber cable 15 and the optical fiber 16 exposed at the distal end side of the optical fiber cable 15. (See FIG. 2). The grooves for guiding the optical fiber cable 15 and the optical fiber 16 are provided corresponding to the lower surface of the cap 12. The cap 12 has a plate shape that closes the opening and the groove of the package case 11. An optical fiber 16 passes through the center of the optical fiber cable 15. The optical fiber 16 has a structure covered with a jacket or the like. Although not shown, the optical fiber 16 includes a core having a diameter of 5 μm and a cladding having a diameter of 125 μm covering the core. This optical fiber 16 is also called an optical fiber core wire.
[0026]
A plurality of leads 17 project from both sides of the bottom surface of the package case 11. This is one of the features of the present invention. These leads 17 extend from the opening 11c of the package case 11 to the vicinity of both side edges of the bottom surface of the package case 11 as shown in FIGS. After extending and protruding from the bottom surface of the package case 11 to the outside of the package case 11, it bends and extends parallel to the bottom surface of the package case 11. That is, the lead 17 has a flat surface portion 17a extending along the inner bottom of the opening 11c, an inclined surface portion 17b extending from the opening 11c toward the bottom surface, and a bent portion parallel to the bottom surface of the package case 11. The mounting portion 17c extends. As shown in FIG. 5, the extension structure of the leads 17 in the package 13 is a so-called gull-wing type. With such a lead structure, the length of the lead is shortened, and the lead inductance can be reduced.
[0027]
For example, the length of the main body 11a of the package 13 is 13.0 mm, the length of the guide 11b is 9.0 mm, the width of the main body 11a is 7.4 mm, and the thickness of the package 13 is 3.0 mm. is there. The height from the mounting surface on the lower surface of the lead 17 to the upper surface of the package 13 is 3.0 mm.
[0028]
In the first embodiment, four leads 17 are provided on each side of the package 13. As shown in FIGS. 1 to 4 and 8, any one of the numbers (1) to (8) is described near the lead 17. This indicates the pin (lead) number, which coincides with the pin number of the equivalent circuit in FIG.
[0029]
Here, the circuit configuration of the optical communication module for transmission 10 of the first embodiment will be described with reference to FIG. A laser diode (LD), a photodiode (PD) for monitoring, a thermistor (Th) for temperature detection, an inductor (L: chip inductor), and a resistor (R: adjustment resistor) are incorporated in the package 13. .
[0030]
A thermistor (Th) is connected between pin (1) and pin (2), a photodiode (PD: light receiving element) is connected to pin (4) and pin (5), and a pin (4) is a cathode for PD. It becomes an electrode, and pin (5) becomes an anode electrode for PD. The pin (6) is connected to an LD (semiconductor laser), serves as an LD anode electrode, and is set to a ground (GND) potential. Pin (3) is connected to an LD via an inductor (L) and serves as a DC bias cathode electrode. The pin {circle around (7)} is connected to the LD via a resistor (R: adjusting resistor) and serves as a cathode electrode for inputting a high-frequency signal (high-frequency signal input section). Pin (8) is a ground terminal.
[0031]
In the package case 11 of the first embodiment, as shown in FIGS. 1 and 4, a wide lead base 19 is provided on the inner bottom of the opening 11 c of the package case 11. The lead base 19 is formed at the same time when the leads 17 are formed, and has the same material and thickness as the leads. The lead base 19 is integrated with one or more leads 17. In the first embodiment, the lead base 19 is integrated with the pins (2), (6), and (8). These pins (2), (6) and (8) serve as ground leads. Therefore, the lead base 19 is at the ground potential.
[0032]
A support substrate (platform) 20 on which components such as optical elements are mounted is fixed to the center of the lead base 19. The support substrate 20 is formed of, for example, a silicon substrate. An insulating film (SiO 2) is formed on the upper surface. ₂ Film) is formed, and a conductor layer is formed on the insulating film in a predetermined pattern. The five leads 17 constituting the remaining pins (1), (3), (4), (5), and (7) which are not set to the ground potential are brought into contact with the lead base 19 at their inner ends. Some of the leads 17 are patterned so as to extend as close to the support substrate 20 as possible. That is, the inner ends of the pins (4), (5) and (7) come close to the support substrate 20.
[0033]
This is one of the features of the present invention. The inner surface of the inclined surface portion 17b of the pin (7) is longer than the other leads 17, so that the flat surface portion 17a of the pin (7) is It is located at a higher position. This is because the electrode surface serving as the wire connection surface of the resistor mounted on the upper surface of the support substrate 20 and the wire connection surface of the flat surface portion 17a of the pin {circle around (7)} have the same or approximate height, and the length of the wire In order to reduce the wire inductance. This resistor is connected to the semiconductor laser device. Further, the resistor is located between the tip of the flat surface portion 17a of the pin {circle around (7)} and the semiconductor laser element, and the wire which reaches the pin {7} serving as a high-frequency signal input part of the semiconductor laser element and the electrode of the semiconductor laser element, The configuration is such that the wiring path via the resistor and the wire is the shortest. This also reduces the inductance of the wire.
[0034]
Here, a method of manufacturing the package case 11 using the lead frame will be described with reference to FIGS. In manufacturing the package case 11, transfer molding is performed on the lead frame 21 as shown in FIG. 8 to form the package case 11. As shown in FIG. 9, a part of the lead frame 21 is incorporated in the package case 11.
[0035]
The lead frame 21 is a metal plate made of an iron-nickel alloy, for example, Kovar, and is formed in a pattern as shown in FIG. If necessary, a predetermined plating film is formed on the surface. The metal plate is formed by etching or press molding, and has a pair of parallel extending outer frames 22 and an inner frame 23 connecting the outer frames 22 at regular intervals. A guide hole 22a is provided in an intermediate portion of the outer frame 22, and is used for transferring and positioning the lead frame 21.
[0036]
Four leads 17 extend from the inside of the pair of inner frames 23, respectively. These eight leads 17 constitute pins (1) to (8). The eight leads 17 are arranged on the left side. This is because the package case 11 including the main body 11a and the guide 11b is formed in a rectangular frame including the outer frame 22 and the inner frame 23. The pins (1) to (4) and the pins (5) to (8) are supported by a dam 24 connected to the pair of outer frames 22. The dams 24 extend a predetermined distance along the edge of the main body 11a of the package case 11, bend in the middle, and extend a predetermined distance along the edge of the guide 11b.
[0037]
The inner ends of the pins {circle around (2)}, {circle around (6)} and {circle around (8)} are connected to a lead base 19 formed on the inner bottom surface of the opening 11c of the main body 11a. Pins (2), (6) and (8) serve as ground leads. The left end of the lead base 19 is connected to the outer frame 22 via a thin connecting piece 19a, and both right and left sides of the lead base 19 are connected to the dam 24 via the connecting piece 19b. Thus, the lead base 19 is supported by the lead frame 21. The inner ends of the pins (1), (3), (4), (5), and (7) are opposed to each other with a predetermined space between them and the lead base (19).
[0038]
The two lines crossing the lead 17 shown in FIG. 8 project from the flat surface portion 17a where the lead 17 is located in the opening 11c, the inclined surface portion 17b penetrating the inside of the main body portion 11a, and the bottom surface of the main body portion 11a (package case 11). The bent lines 25a and 25b for forming the mounting portion 17c formed by bending after the bending. However, in the pin {circle around (7)}, as described above, since the inclined surface portion 17b extends long toward the opening 11c of the package case 11, the bending line is bent by the center side of the package case 11 to form the bending line 25b '. It has become.
[0039]
In FIG. 8, each lead 17 is cut, the dam 24 is cut and removed, and the connecting pieces 19a and 19b protruding outward from the main body 11a of the package case 11 are cut to separate the lead base 19 from the lead frame 21. Thus, the package case 11 shown in FIG. 2 can be manufactured.
[0040]
In such a package case 11, as shown in FIG. 1, the optical fiber cable 15 is inserted into the groove 14a of the package case 11, and the optical fiber cable 15 is inserted into the groove 14b provided on the extension of the groove 14a. The optical fiber 16 stripped of the jacket and guided is guided. The distal end portion of the optical fiber 16 extends on the support substrate 20, as shown in FIG. Although not shown, a guide groove having a V-shaped cross section is provided on the upper surface of the support substrate 20 fixed to the inner bottom of the opening 11c of the package case 11, and the optical fiber 16 is guided in the guide groove.
[0041]
A semiconductor laser element (LD) 30 is fixed at the center of the upper surface of the support substrate 20. Then, forward emission light (laser light) emitted from the front emission surface of the semiconductor laser element 30 is taken into the core of the optical fiber 16. After the optical axis alignment, the optical fiber 16 is fixed to the support substrate 20 and the package case 11 with an adhesive (not shown), and the optical fiber cable 15 is fixed to the package case 11.
[0042]
Further, a light receiving element (photodiode) 31 for receiving the rear emission surface (laser light) of the semiconductor laser element 30 is fixed to the upper surface of the support substrate 20. A resistor (adjustment resistor) 32 is fixed on the upper surface of the support substrate 20. As shown in FIGS. 3 and 6, the semiconductor laser element 30, the light receiving element 31, and the resistor 32 are all fixed on a conductive layer on the surface of the support substrate 20 via a conductive adhesive.
[0043]
As shown in FIGS. 3 and 6, an inductor (L) 33 and a thermistor (Th) 34 for detecting temperature are mounted on predetermined portions of the lead base 19 exposed in the opening 11c via a conductive adhesive. Have been. 3 and 6, the conductive portions of the leads 17, the lead base 19 and the support substrate 20 are shown with dots.
[0044]
The semiconductor laser element 30, the light receiving element 31, the inductor 33, and the thermistor 34 have a structure having electrodes on the upper surface and the lower surface, and the resistor 32 has two different electrodes on the upper surface. The electrodes of each component, the leads 17, the lead base 19, and the conductor layers (not numbered) on the surface of the support substrate 20 are connected by conductive wires 35, respectively, to form the circuit shown in FIG. As the wire 35, for example, an Au wire is used. It should be noted that in some of the drawings, reference numerals for components, wires, and the like are omitted because the drawings are too small to be easily understood.
[0045]
In the inductor (L) 33, the central part of the spirally extending conductor layer is electrically connected to the upper electrode of the semiconductor laser element 30 via the wire 35, and the final end of the spiral is connected to the pin (3). They are electrically connected via conductive wires 35.
[0046]
The resistor 32 has a structure in which a resistive layer is provided on the upper surface of an insulating substrate, electrodes having different polarities are provided on both upper surfaces of the resistive layer, and electrodes are also provided on the lower surface of the substrate. Accordingly, one electrode of the resistor 32 is connected to one electrode of the semiconductor laser device 30 via the wire 35, and the other electrode of the resistor 32 is connected to the pin {circle around (7)} via the wire 35. The wiring path from the pin {circle around (7)} to the electrode of the semiconductor laser element 30 is substantially linear and has the shortest distance, so that the inductance of the wire can be reduced. Further, since the height of the wire connection surface of the pin {circle around (7)} and the electrode surface of the resistor 32, that is, the height of the wire connection surface are substantially the same, the length of the wire 35 is also reduced, and the inductance of the wire is reduced. Will be done. That is, impedance mismatch can be reduced.
[0047]
In the first embodiment, the support substrate 20 is formed of a silicon single crystal plate called a silicon platform. The support substrate 20 is made of a material having a thermal expansion coefficient close to that of an optical element such as a semiconductor laser chip or a photodiode chip or quartz constituting an optical fiber. Therefore, the support substrate 20 may be an insulating substrate such as aluminum nitride or silicon carbide other than silicon.
[0048]
This is one of the features of the present invention. The pin (7), the ground leads (pin (6), pin (8)) on both sides of the pin (7), and the plastic forming the package case 11 Is a coplanar transmission line whose impedance is matched to 25Ω. In order to make the coplanar transmission line impedance-matched to 25Ω, the width of the gap between the signal line width (pin {circle around (7)) and the ground line (pin {circle around (6)}, pin {circle around (8)}) should be adjusted appropriately. can get.
[0049]
The package case 11 is filled with a protective film 40 (see FIG. 5) which is transparent to the light transmitted through the optical fiber 16 and which is resistant to moisture. The protective film 40 includes the lead base 19, a lead portion extending around the lead base 19, the support substrate 20, the semiconductor laser element 30, the light receiving element 31, the resistor 32, the inductor 33, the thermistor 34, the optical fiber 16, and the like. In addition, the semiconductor laser element 30 and the light receiving element 31 are improved in moisture resistance.
[0050]
The protective film 40 is, for example, a flexible silicone gel. The protective film 40 is not limited to the silicone gel, but may be another material such as a silicone rubber, a low-stress epoxy resin, an acrylic resin, or a urethane resin.
[0051]
Forward emitted light (laser light) emitted from the semiconductor laser element 30 passes through the protective film 40 and is taken into the core of the optical fiber 16, and backward emitted light (laser light) transmits through the protective film 40 and received by the light receiving element. The light reaches the light receiving surface 31. The protective film 40 is, for example, a soft gel silicone resin. The refractive index of the silicone resin at a wavelength of 1.3 μm is 1.4, which substantially matches the refractive index of the optical fiber. The protective film 40 is not limited to the silicone resin, but may be another material such as a silicone rubber, a low-stress epoxy resin, an acrylic resin, or a urethane resin.
[0052]
In the manufacture of such an optical communication module for transmission 10, after mounting components on the support substrate 20 first, the support substrate 20 is fixed on the lead base 19 exposed at the inner bottom of the opening 11 c of the package case 11. I do. In addition, necessary parts are also mounted on the package case 11. Thereafter, a predetermined portion is connected with a conductive wire, and then the optical fiber 16 is attached. Furthermore, after covering the support substrate 20 and various components on the upper surface of the package case 11 with the protective film 40, the cap 12 is attached to manufacture the optical communication module 10 for transmission.
[0053]
FIG. 10 is a schematic diagram showing a mounting state of the optical communication module 10 for transmission. That is, the mounting portion 17c of the lead 17 of the optical communication module for transmission 10 is overlaid on the land 46 on the upper surface of the mounting board 45, and is mounted with a bonding material 47 such as solder. FIG. 11 shows a state where the driver IC 50 for driving and controlling the transmission optical communication module 10 and the transmission optical communication module 10 are mounted on the mounting board 45. The wiring 51 for transmitting the control signal of the driver IC 50 is connected to the pin {circle around (7)} of the transmitting optical communication module 10, and inputs a high frequency signal to the transmitting optical communication module 10 via the pin {circle around (7)}.
[0054]
FIG. 12 is a diagram showing three modified examples of the first embodiment, showing a package case 11 of an optical communication module (optical communication device) 10 for transmission and an optical communication device manufactured using the case 11. FIG.
[0055]
FIG. 12A shows a state in which the outer end of the mounting portion 17 c of the lead 17 is aligned with the side surface of the package case 11. This structure can reduce the mounting area.
[0056]
FIG. 12 (b) shows an outer end of the mounting portion 17 c of the lead 17 extending outside the package case 11. The mounting portion 17c of the lead 17 has a structure extending along the bottom surface of the package case 11.
[0057]
FIG. 12C shows an outer end of the mounting portion 17 c of the lead 17 located inside the outer surface of the package case 11.
[0058]
According to the first embodiment, the following effects can be obtained.
(1) Inside the package case 11, a coplanar transmission line whose impedance is matched to 25Ω is formed, so that the propagation loss in the lead (pin {circle around (7)}) constituting the high-frequency signal input section can be reduced, and the optical communication module for transmission can be achieved. (Optical communication device) The high-frequency characteristics of the optical communication device 10 are improved. That is, a low-loss transmission line is formed inside the plastic package.
[0059]
(2) Since the lead 17 includes the flat surface portion 17a, the inclined surface portion 17b connected to the flat surface portion 17a, and the mounting portion 17c connected to the inclined surface portion 17b, the length of the lead 17 can be reduced. The inductance can be reduced, and the high-frequency characteristics of the optical communication device can be improved.
[0060]
(3) In the lead 17 (pin {circle around (7)}) serving as a high-frequency signal input portion of the semiconductor laser element 30, the inclined surface portion 17b is longer than the other leads 17, and the height of the flat surface portion 17a is higher than the lead base 19 surface. Since the wire connection surface of the flat surface portion 17a and the wire connection surface at the other end of the wire 35 connected to the wire connection surface are at the same height or close to each other, the length of the wire 35 is reduced. As a result, the inductance of the wire 35 can be reduced, and the high frequency characteristics of the optical communication device can be improved.
[0061]
(4) According to the above (1) to (3), it is possible to provide an optical communication device having good high-frequency characteristics from impedance matching and inductance reduction.
[0062]
(5) The lead 17 (pin {circle around (7)}) is extended from the side of the lead base 19 that supports the support substrate 20 on which the semiconductor laser element 30 is mounted, so that the lead length is reduced as in (2) above. In other words, since the wiring path between the semiconductor laser element 30 and the lead 17 (pin {circle around (7)}) serving as a high-frequency signal input section can be made the shortest, the propagation loss can be reduced, and the optical communication device can be reduced. The improvement of the high-frequency characteristics can be achieved.
[0063]
(6) Since the package 13 is made of plastic, the manufacturing cost of the optical communication device can be reduced.
[0064]
(7) Since the coplanar transmission line is formed by the package case and the lead made of plastic, the cost of the optical communication device operating at high speed can be reduced.
[0065]
(Embodiment 2)
13 to 19 relate to an optical communication device (transmission optical communication module) according to another embodiment (Embodiment 2) of the present invention. 13 is a perspective view showing the inside of the optical communication device, FIG. 14 is a perspective view showing a part of the inside of the optical communication device, FIG. 15 is a plan view of the optical communication device with a cap removed, and FIG. FIG. 17 is a plan view showing a part of the inside of the optical communication apparatus. FIG. 18 is a plan view showing a state in which a case is formed on a lead frame used in the manufacture of an optical communication device, and FIG. 19 is a cross-sectional view taken along line BB of FIG. Note that some of the reference numerals are omitted in each drawing because the drawings are difficult to see.
[0066]
The optical communication device of the second embodiment is similar in many respects to the optical communication module for transmission 10 of the first embodiment, but is partially different. That is, in the first embodiment, the resistor 32 is disposed on the platform 20. In the second embodiment, however, a substrate 61 (a grounded coplanar transmission line substrate: GCPW) formed of a flat rectangular parallelepiped with a thin film resistor 60 with a via hole attached to the side of the platform 20 Substrate). A thin-film resistor 60 with a via hole is mounted on the upper surface of the substrate 61. One electrode of the thin-film resistor 60 is located on the side of the semiconductor laser device 30 and is connected to the upper electrode of the semiconductor laser device 30 by a wire 35. (See FIG. 14). The other electrode of the thin-film resistor 60 is located on the opposite side, and is connected to the lead 17 constituting the pin {circle around (7)} via the wire 35.
[0067]
Conductive layers 62 are provided on both sides of the thin film resistor 60, respectively. Although not shown, these conductor layers 62 are connected to pins (6) and (8) serving as ground leads via wires 35, and the platform 20 is connected via wires 35 (not shown). Is connected to the ground layer (conductor layer) on the upper surface of the. As a result, a grounded coplanar transmission line whose impedance is matched to 25Ω as in the first embodiment is formed. Therefore, a low-loss transmission line is formed inside the plastic package.
[0068]
Since a substrate 61 having a predetermined thickness is fixed on the lead base 19 and the height of the wire connection surface on the substrate 61 is increased, as shown in FIG. The lead portion leading to ▼ is bent so as to be stepwise stepwise so as to make the heights of the wire connection surfaces at the pins 6 to 8 the same. Since the height of the wire connection surface at the two points where wire bonding is performed is the same, connection with the shortest wire length is possible, and the inductance of the wire can be reduced. In addition, impedance mismatch can be reduced.
[0069]
In the second embodiment, the lead portions (including the lead base 19) of the pins (5) to (8) are one step higher than the lead heights (including the lead base 19) of the pins (1) to (4). For this purpose, as shown in FIG. 18, the lead frame 21 used for manufacturing the package case 11 is cut and separated at the outer frame 22.
[0070]
In the second embodiment, as shown in FIGS. 19 and 16, the bending position of the lower end of the inclined surface portion 17 b of the lead 17 is set in the main body 11 a of the package case 11, that is, in the plastic, and the lead 17 is packaged. 13 and 16, when the lead is formed, a portion extending straight from the side surface of the package case 11 to the side is bent into a gull wing shape. In this structure, the length of the lead 17 is longer than that of the first embodiment, but the gull-wing type lead is easy to make, soldering to the mounting board is easy, and the mounting board and the package are connected to each other. Is effective in alleviating the stress caused by the difference in thermal expansion coefficient between the two.
[0071]
In the transmission optical communication module 10 of the second embodiment, the ground 7 is formed by separating the lead base 19 from the pin 7 serving as a high-frequency signal input lead and the ground leads (pin 6 and pin 8) on both sides thereof. The ground leads (pins 6 and 8) and the ground of the lead base 19 are connected with very small inductance by placing a grounded coplanar transmission line (GCPW) substrate with a thin film resistor with via holes. Let it. Thereby, resonance caused by the parasitic capacitance in the lead and the package can be prevented.
[0072]
Although the invention made by the inventor has been specifically described based on the embodiment, the present invention is not limited to the above embodiment, and various changes can be made without departing from the gist of the invention. Nor.
[0073]
【The invention's effect】
The effects obtained by the typical inventions among the inventions disclosed in the present application will be briefly described as follows.
[0074]
(1) An optical communication device having excellent high-frequency characteristics can be provided.
[0075]
(2) An optical communication device with small propagation loss can be provided.
[0076]
(3) An impedance-matched optical communication device with a low inductance value can be provided.
[0077]
(4) An optical communication device that can be reduced in cost can be provided.
[Brief description of the drawings]
FIG. 1 is a perspective view showing the inside of an optical communication device according to an embodiment (Embodiment 1) of the present invention.
FIG. 2 is a perspective view of the optical communication device with a cap removed.
FIG. 3 is a perspective view showing a part of the inside of the optical communication apparatus.
FIG. 4 is a plan view of the optical communication device with a cap removed.
FIG. 5 is a sectional view of the optical communication device.
FIG. 6 is a plan view showing a part of the inside of the optical communication apparatus.
FIG. 7 is an equivalent circuit diagram of the optical communication device.
FIG. 8 is a plan view showing a state in which a case is formed in a lead frame used in manufacturing the optical communication device.
FIG. 9 is a sectional view taken along line AA of FIG. 7;
FIG. 10 is a schematic diagram showing a mounting state of the optical communication device.
FIG. 11 is a schematic perspective view showing a state where the optical communication device and the driver IC are mounted on a mounting board of the optical communication device.
FIG. 12 is a diagram illustrating three modified examples of the first embodiment, illustrating a case of the optical communication device and a mounting state of the optical communication device manufactured using the case.
FIG. 13 is a perspective view showing the inside of an optical communication device according to another embodiment (Embodiment 2) of the present invention.
FIG. 14 is a perspective view showing a part of the inside of the optical communication apparatus according to the second embodiment.
FIG. 15 is a plan view of the optical communication device according to the second embodiment with a cap removed.
FIG. 16 is a cross-sectional view of the optical communication device according to the second embodiment.
FIG. 17 is a plan view showing a part of the inside of the optical communication apparatus according to the second embodiment.
FIG. 18 is a plan view showing a state where a case is formed in a lead frame used in manufacturing the optical communication device of the second embodiment.
FIG. 19 is a sectional view taken along the line BB of FIG. 17;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Optical communication module (optical communication apparatus) for transmission, 11 ... Package case, 11a, 12a ... Body part, 11b, 12b ... Guide part, 11c ... Opening, 12 ... Cap, 13 ... Package (sealing body), 14a, 14b groove, 15 optical fiber cable, 16 optical fiber, 17 lead, 17a flat surface portion, 17b inclined surface portion, 17c mounting portion, 19 lead base, 19a, 19b connecting piece, 20 ... Support substrate (platform), 21: lead frame, 22: outer frame, 22a: guide hole, 23: inner frame, 24: dam, 25a, 25b, 25b ': bending line, 30: semiconductor laser element, 31: light receiving element (Photodiode), 32: resistance (adjustment resistance), 33: inductor (L), 34: thermistor (Th), 35: wire, 40: protective film, 45: mounting Substrate, 46 land, 47 bonding material, 50 driver IC, 51 wiring, 60 thin film resistor, 61 substrate, 62 conductive layer.

Claims (5)

A package case made of plastic and having an opening on an upper surface,
A cap for closing the upper surface of the package case,
A plurality of metal leads that extend over the inside and outside of the package case and serve as electrode terminals,
A lead base disposed on the inner bottom of the package case and integrally formed with at least one or a plurality of the leads;
A support substrate fixed on the lead base and having a conductor pattern of a predetermined pattern on the upper surface,
An optical element fixed on the support substrate,
An optical fiber that extends over the inside and outside of the package case, and is fixed on the support substrate so that an inner end faces the optical element and transmits and receives light to and from the optical element,
One or more electronic components fixed to leads including the lead base in the package case;
An optical communication device comprising: a conductive wire that electrically connects each of the electrode of the optical element, the electrode of the electronic component, the conductive layer of the support substrate, and the lead as necessary,
Of the leads, the signal lead constituting the high-frequency signal input unit is arranged on both sides thereof with ground leads serving as ground electrodes separated by a predetermined distance, and the signal lead and the ground leads on both sides and the signal lead and the ground lead are connected to each other. An optical communication device, wherein a coplanar transmission line whose impedance is matched by the package case portion to be supported is configured. The lead includes a flat surface portion located at the opening and connected to the wire, an inclined surface portion connected to the flat surface portion, and a mounting portion connected to the inclined surface portion and having a tip portion protruding from the package case. The optical communication device according to claim 1, wherein: The lead serving as a high-frequency signal input unit of the optical element has the inclined surface portion longer than other leads, the flat surface portion has a height higher than the lead base surface, and the flat surface portion has a wire connection surface and The optical communication device according to claim 1, wherein a wire connection surface at the other end of the wire connected to the wire connection surface has the same height or a close height. The optical communication device according to claim 1, wherein the optical element, the electronic component, the wires, and the like in the package case are covered and protected by a transparent protective layer. The optical communication device according to claim 1, wherein the optical element that transmits and receives light to and from the optical fiber is a semiconductor laser element.

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