JP2002023028A - Optical communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent the deterioration of optical parts and to lower the error rate of information transmission. SOLUTION: A pad 5 and a lead frame 6 are embedded in a resin case 7, a silicon substrate 4 is conductively adhered on the pad 5, and a semiconductor laser 1 and a photodetector 3 are formed on the silicon substrate 4. Then, the silicon substrate 4 is provided with an optical fiber 2, transparent resins are filled in the semiconductor laser 1, the optical fiber 2, the photodetector 3 and the silicon substrate 4, and a resin case 7 is covered with a lid (not shown in figure) composed of a resin. Then, the resin case 7 and the lid are fixed by an adhesive (not shown in figure), and an air hole 9 curved equally to or more than the diameter is provided at a part where the resin case 7 and the lid are overlapped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical communication device such as an optical transmitter and an optical receiver used in an optical communication system.

[0002]

2. Description of the Related Art Means for modulating output light of a semiconductor laser with an electric signal modulated by information, means for transmitting the modulated light by an optical fiber, receiving the modulated and transmitted light by a photodetector, and converting the light into an electric signal. Optical communication systems having means for conversion have already been laid between nations, cities, and communication stations by submarine cables, etc., and have come to provide information communication means that is indispensable to our lives, called the trunk system. ing.
However, with the advent of the highly information-oriented society in recent years, the demand for larger communication capacity and higher speed has been increasing day by day. Pillars (curves, closures) up to (F
TTC (Fiber to the curb), HFC (Hybrid Fiber)
Coax)) or to each home (FTTH (Fiber To The
Home)), and ultimately, personal computers, as well as conventional electrical cables, are being laid out directly at home and abroad to install optical fibers with much higher speed and larger transmission capacity. Realize such a plan,
One of the biggest issues for widespread use is cost reduction of optical transmitters and optical receivers arranged in each terminal.

In an optical transceiver (optical module) used in a conventional trunk system, light from a semiconductor laser is coupled to an optical fiber via an imaging lens so that optical coupling to the optical fiber is maximized. In order to prevent the deterioration of the semiconductor laser, the sub-assembly consisting of the semiconductor laser etc. is completely hermetically sealed in a package made of metal or ceramic to prevent the deterioration of the optical components such as the semiconductor laser. The structure is such that moisture that promotes the moisture does not enter. However, in such an optical transceiver, the cost of each component and the cost of assembly cannot be reduced, and it is extremely difficult to realize the aforementioned cost reduction.

For this reason, instead of assembling a semiconductor laser or a lens as a three-dimensional bulk component, a surface mounting method such as an LSI in electronics is used for an optical transmitter,
Attempts have been made to adopt the optical receiver, that is, an attempt to reduce the cost by using a resin package instead of a package made of metal or ceramic. However, in the resin package, since the resin always passes through the moisture, it is necessary to take measures to prevent the moisture from directly reaching the optical component (chip).

For this reason, a subassembly in which a semiconductor laser, a photodetector and an optical fiber are arranged on a silicon waveguide substrate is filled with a transparent silicone resin, and this is housed in a resin packaging consisting of a resin case and a lid. Optical transmitters and optical receivers that prevent moisture from directly hitting a semiconductor laser or a photodetector have been considered.

[0006]

However, since the resin or the resin-bonded portion allows moisture to pass through, if the outside air temperature or humidity fluctuates, the moisture will not accumulate in the resin package and will not be exhausted to the outside. There is a disadvantage that it occurs.
Furthermore, when a ventilation hole for ventilation is provided in the resin package, external light is incident on a photodetector, a semiconductor laser, or an optical fiber, photoelectric conversion is performed by the external light, and noise is generated in a signal. The disadvantage is that the error rate is increased. Further, there is a possibility that water droplets may enter the package through the ventilation holes.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an optical communication device which can surely prevent deterioration of an optical component and has a low information transmission error rate. I do.

[0008]

In order to achieve this object, the present invention provides an optical communication device in which an optical component and an optical fiber covered with a transparent resin are provided in a resin package. It is configured to allow internal and external ventilation.

[0009]

FIG. 1 is a plan view showing a state in which a cover and a transparent resin of an optical transmitter according to the present invention are removed, and FIG.
1 is a front sectional view showing the optical transmitter shown in FIG. 1, and FIG. 3 is a front view showing the optical transmitter shown in FIG. As shown in the figure, a pad 5 and a lead frame 6 are embedded in a resin case 7 formed by injection molding or transfer molding of a resin, and the pad 5 and a part of the lead frame 6 are integrated. Further, a silicon substrate 4 having a V groove (not shown) provided on the pad 5 is conductively bonded, and the semiconductor laser 1 and the photodetector 3 are mounted on the silicon substrate 4. The optical fiber 2 is mounted, and the optical fiber 2 is
, A subassembly 15 is constituted by the semiconductor laser 1, the optical fiber 2, the photodetector 3, and the silicon substrate 4. Further, the sub-assembly 15 is filled with a transparent resin 8 such as a silicone resin, the resin case 7 is covered with a lid 10 made of resin, and the resin case 7 and the lid 10 are fixed with an adhesive (not shown). A resin package 16 is constituted by the resin case 7 and the lid 10. Further, a ventilation hole 9 is provided in a portion of the resin package 16 where the resin case 7 and the lid 10 are combined, and the ventilation hole 9 is bent to a diameter or more.

In this optical transmitter, output light of the semiconductor laser 1 is modulated by an electric signal modulated by information, and the modulated light modulated by the semiconductor laser 1 is transmitted to the optical fiber 2. The output light on the opposite side of the semiconductor laser 1 is monitored by the photodetector 3.

In such an optical transmitter, since the transparent resin 8 is filled on the sub-assembly 15, even if the resin package 16 is permeable to moisture, the semiconductor laser 1 as an optical component and the optical detector 3 Since it is possible to prevent moisture from entering the semiconductor laser 1, it is possible to prevent the semiconductor laser 1 and the photodetector 3 from deteriorating. In addition, since the ventilation holes 9 are provided in the resin package 16, the humidity inside the resin package 16 does not elapse for a long time with the humidity increased, so that the limit of the moisture resistance of the transparent resin 8 is not adversely affected. , The intrusion of moisture into the semiconductor laser 1 and the photodetector 3 can be reliably prevented.
Degradation can be reliably prevented. Furthermore, since the ventilation hole 9 is bent, external light does not enter the semiconductor laser 1, the photodetector 3, the optical fiber 2, etc. in the resin package 16, so that photoelectric conversion by external light is performed. As a result, the occurrence of noise in the signal can be prevented, and the error rate of information transmission decreases.

FIG. 4 is a plan view showing a state in which the lid and the transparent resin of the optical receiver according to the present invention are removed, and FIG. 5 is a front sectional view showing the optical transmitter shown in FIG. As shown in the figure, a photodetector 11 is mounted on a silicon substrate 4, and an optical fiber 2,
A subassembly 17 is formed by the photodetector 11 and the silicon substrate 4, an amplifier 12 is provided near the subassembly 17, and the subassembly 17 and the amplifier 12 are filled with a transparent resin 8.

In this optical receiver, the signal light from the optical fiber 2 reaches the photodetector 11, is photoelectrically converted by the photodetector 11, and the electric signal from the photodetector 11 is converted into an amplifier 1
Amplified by 2.

In such an optical receiver, since the dark current of the optical detector 11 is sensitive to moisture, it is important to take measures against moisture. However, since the ventilation holes 9 are provided, the optical detector 1 is not provided.
1 can be reliably prevented from entering, so that the photodetector 11, which is an optical component, can be surely prevented from deteriorating. In addition, since the ventilation hole 9 is bent, external light does not enter the photodetector 11, the optical fiber 2, etc. in the resin package 16, so that photoelectric conversion by external light is not performed. Noise can be prevented from being generated in the signal, and the error rate of information transmission is reduced.

FIG. 6 is a sectional view showing another optical transmitter according to the present invention. As shown in the figure, the cover 10 is provided with a vent hole 14, and the vent hole 14 is bent to a diameter or more.
The height of the outer portion of the resin package 16 is
6 Lower than the height of the inner part.

In this optical transmitter, the ventilation hole 14 is provided in the lid 10 of the resin package 16, so that the invasion of moisture into the semiconductor laser 1 and the photodetector 3 can be reliably prevented. Deterioration of the laser 1 and the photodetector 3 can be reliably prevented. Further, since the vent hole 14 is bent, external light does not enter the optical components such as the semiconductor laser 1, the photodetector 3, and the optical fiber 2 in the resin package 16, so that the error rate of information transmission is reduced. Lower.
Further, since the height of the outside of the resin package 16 of the ventilation hole 14 is lower than the height of the inside of the resin package 16, it is possible to prevent water droplets from entering the ventilation hole 14, thereby improving reliability. I do.

Although the optical transmitter and the optical receiver have been described in the above embodiments, the present invention can be applied to other optical communication devices such as an optical transceiver.

[0018]

In the optical communication device according to the present invention, since the humidity in the resin package does not elapse for a long time with the rise, the invasion of moisture into the optical component can be surely prevented. The deterioration of components can be reliably prevented, and since external light does not enter the optical components in the resin package, photoelectric conversion by external light does not take place. Become.

Further, when the height of the outside of the resin package of the ventilation hole is smaller than the height of the inside of the resin package, it is possible to prevent water droplets from entering from the ventilation hole, thereby improving reliability.

[Brief description of the drawings]

FIG. 1 is a plan view showing a state where a cover and a transparent resin of an optical transmitter according to the present invention are removed.

FIG. 2 is a front sectional view showing the optical transmitter shown in FIG. 1;

FIG. 3 is a front view showing the optical transmitter shown in FIG.

FIG. 4 is a plan view showing a state in which a cover and a transparent resin of the optical receiver according to the present invention are removed.

FIG. 5 is a front sectional view showing the optical transmitter shown in FIG. 4;

FIG. 6 is a sectional view showing another optical transmitter according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Semiconductor laser 2 ... Optical fiber 3 ... Photodetector 4 ... Silicon substrate 7 ... Resin case 8 ... Transparent resin 9 ... Vent hole 10 ... Lid 11 ... Photodetector 14 ... Vent hole 15 ... Subassembly 16 ... Resin package 17 … Subassembly

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshinori Hirataka 1-280 Higashi Koikekubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory of Hitachi, Ltd. Inside the Central Research Laboratory of the Works (72) Inventor ▲ Shoichi Hashi 5-20-1, Kamizuhoncho, Kodaira-shi, Tokyo Within Semiconductor Division, Hitachi, Ltd. (72) Inventor Hiroshi Nakami Kamishimihoncho, Kodaira-shi, Tokyo 5-20-1 F-term in the Semiconductor Division, Hitachi, Ltd. F-term (reference) 2H037 AA01 BA02 BA11 DA03 DA04 DA35 DA37 5F073 BA01 EA27 EA28 FA02 FA13 FA28 FA29

Claims (4)

[Claims] An optical communication device comprising an optical component and an optical fiber covered with a transparent resin provided in a resin package, wherein air can flow between the inside and the outside of the resin package. apparatus. 2. An optical communication device in which an optical component and an optical fiber covered with a transparent resin are provided in a resin package composed of a case and a lid, wherein a gap is formed at a joint between the case and the lid. An optical communication device characterized by being present. 3. An optical communication device in which an optical component and an optical fiber covered with a transparent resin are provided in a resin package, wherein the resin package has a ventilation hole. 4. An optical communication device in which an optical component and an optical fiber covered with a transparent resin are provided in a resin package, wherein the resin package has a non-hermetic structure.