JP2009230048A - Optical module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical module capable of preventing an alignment from being affected even when being mounted on a moving object such as an airplane or a vehicle, and also preventing internal circuits from being affected when being used in a high-temperature and high-humidity environment, thereby improving reliability during usage, and to provide a connector provided with the optical module. <P>SOLUTION: A resin coating part 30 made of a transparent resin is provided in a space part 31 located between a can cap 4 and a receptacle 5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a single-core bidirectional module used for optical fiber wiring of electronic circuits such as automobiles and airplanes, and relates to a structure of an optical module that can improve reliability in use.

Conventionally, the module housing | casing shown by patent document 1 is known. This module housing is configured such that an electronic board on which electronic components are mounted is housed in a metal base member, and a metal cover is fitted on the base member.
Japanese Utility Model Publication No. 7-27189

  By the way, in recent years, an optical module composed of a single-core bidirectional module is sometimes provided on an electronic board accommodated in the module housing as described above in order to increase transmission capacity instead of metal wiring. The optical module includes an integrated optical circuit chip on which a light emitting element and a light receiving element are mounted, a stem that supports the integrated optical circuit chip, a hermetic seal covering the integrated optical circuit chip on the stem, and the integrated optical circuit. A can cap provided with a ball lens for imaging light onto the chip, and a receptacle provided on the same line as the ball lens and spaced from the ball lens, in which a ferrule of an optical fiber is held. And optical signals are input and output bidirectionally between the optical fiber held in the receptacle and the elements on the integrated optical circuit chip through the ball lens of the can cap.

  If such an optical module is mounted on a moving body such as an airplane or a vehicle, the vibration of the moving body causes a displacement between the ferrule of the optical fiber and the ball lens of the can cap, which affects the alignment. There is a problem that comes out. In addition, when mounted on a moving body, there is a problem that the operation of the internal circuit is affected by the use in a high temperature environment or a humid environment depending on the destination or in-vehicle or in-vehicle conditions.

  The present invention has been made in view of the above-described circumstances, and even when mounted on a moving body such as an airplane or a vehicle, the alignment can be prevented from being affected, and high temperature An object of the present invention is to provide an optical module that can prevent an internal circuit from being affected even when used in a humid environment, thereby improving reliability during use.

  In order to solve the above problems, the present invention proposes the following means. That is, the present invention relates to an integrated optical circuit chip on which a light emitting element and a light receiving element are mounted, a stem that supports the integrated optical circuit chip, a hermetic seal covering the integrated optical circuit chip on the stem, and the integrated optical A can cap in which a ball lens is installed so as to be optically coupled to the circuit chip, and the ball lens and the optical fiber are optically coupled to the inside of the can cap that is spaced from the ball lens. A receptacle holding an optical fiber ferrule so that light is transmitted bidirectionally between the optical fiber held by the receptacle and the element on the integrated optical circuit chip through the ball lens of the can cap. An optical module for inputting and outputting signals, and a gap formed between the can cap and the receptacle is made of a resin made of transparent resin. Wherein the covering portion is provided.

  According to the above configuration, since the resin coating portion made of transparent resin is formed in the gap portion located between the can cap and the receptacle, the resin coating portion supports the receptacle supporting the ferrule of the optical fiber, and the can. The cap ball lens can be fixed and held so as to be located on the same line, and optical signals can be transmitted and received between the can cap and the receptacle. In addition, since the resin-coated portion in the gap between the can cap and the receptacle seals the gap between the can cap and the receptacle, moisture (in It is possible to prevent intrusion of water (including water vapor included). That is, for example, in the conventional case, moisture enters the cap once, particularly in a low temperature state, and condensation occurs on the fiber or the lens, resulting in an optical blockage. Since the gap portion located between the can cap and the receptacle is filled with the transparent resin, it is possible to prevent moisture from entering the gap and to prevent optical blockage due to condensation. In addition, the transparent resin filled in the gap between the can cap and the receptacle generally has a higher thermal conductivity than air. Therefore, the transparent resin is generated in the optical circuit in the can cap through the transparent resin having good conductivity. Heat can be efficiently discharged to the receptacle side, and as a result, it is possible to prevent the optical circuit from being troubled even when used in a high temperature environment.

  In the present invention, the resin coating portion is constituted by a connecting portion provided in a gap portion between the can cap and the receptacle, and an exterior portion covering an outer peripheral surface of the can cap and the receptacle.

  According to the above configuration, as the resin coating portion, the connecting portion provided in the gap between the can cap and the receptacle and the exterior portion covering the outer peripheral surface of the can cap and the receptacle are provided. Alignment, thermal conductivity and waterproofing can be improved, and the outer cap protects the can cap having the integrated optical circuit chip inside and the receptacle holding the ferrule from outside shocks. Can do. Moreover, the resin coating part which consists of such a connection part and an exterior part does not arrange | position the special connecting cylindrical member for protecting a can cap from an external impact, but is a resin coating part which is one member. Thus, the can cap and the receptacle can be protected at the same time as the above-described alignment, thermal conductivity and waterproofing are improved.

  In the present invention, the transparent resin of the resin coating portion is formed of an acrylic resin. Moreover, in this invention, transparent resin of the said resin coating part is formed with polyetherimide resin, It is characterized by the above-mentioned. In the present invention, the transparent resin of the resin coating portion is formed of a polycarbonate resin.

  The optical module configured as described above can prevent alignment from being affected even when mounted on a moving body such as an airplane or a vehicle, and can be used in a high temperature / humidity environment. Even in this case, it is possible to prevent the internal optical circuit from being affected, and this makes it possible to greatly improve the reliability during use.

  An embodiment of the present invention will be described with reference to FIGS. 1 and 2 show an optical module according to the present invention. This optical module is configured by a micro BOSA 1 that is a microminiature bi-directional optical subassembly (MICRO COMPACT BI-DIRECTIONAL OPTICAL SUBASSEBBLY). Specifically, the micro BOSA 1 includes a stem 3 on which a micro BOSA chip 2 that is an integrated optical circuit chip is mounted, and a lens cap with a ball for covering and sealing the micro BOSA chip 2 (hereinafter referred to as a can cap). 4) and a receptacle 5 made of, for example, an SC type optical connector that holds the ferrule F of the optical fiber.

  As shown in detail in FIGS. 3 and 4, the micro BOSA chip 2 includes a PD chip (photodiode) 10, an LD chip (laser diode) 11, a WDM filter (wavelength division multiplexing filter) 12, and a silicon micro And a lens 13. The PD chip 10 is mounted on the silicon substrate 15 via the glass substrate 14. On the silicon substrate 15, a TIA (transimpedance amplifier) 16 and a ceramic substrate 17 serving as a circuit board are mounted.

  The silicon microlenses 13 are so-called diffractive lenses, and are arranged at two locations as indicated by reference numerals 13A and 13B in order to realize a space coupling type single core bidirectional function in a compact manner. As shown in FIG. 4, one silicon microlens 13A is disposed between the LD chip 11 and the WDM filter 12, and collimates the light emitted from the LD chip 11 (for example, a 1310 mm optical signal). For example, an aspherical proximity silicon microlens. The other silicon microlens 13B is disposed between the PD chip 10 and the WDM filter 12, and converges incident light (for example, an optical signal of 1490 mm) from the WDM filter 12 to the PD chip 10. For example, it is composed of an aspherical proximity silicon microlens for guiding. In FIG. 4, symbol (A) indicates an optical path of a 1310 mm output signal, and symbol (B) indicates an optical path of an input signal of 1490 mm. Both silicon microlenses 13A and 13B are mounted, for example, in a V-groove (not shown) provided in the silicon substrate 15 by passive alignment technology.

  The PD chip 10 includes, for example, a so-called PIN photodiode having a structure in which an intrinsic semiconductor layer (INTRINSIC) is placed in the middle of a pn junction. The PD chip 10 is mounted face down with the light receiving surface facing downward, and the light that has passed through the silicon microlens 13 is incident thereon.

  The can cap 4 has a cylindrical shape whose one end is closed (that is, formed in a can shape), a cap 18 whose edge on the opening side is coupled to the stem 3, and a penetrating through the center of the closed one end of the cap 18. And a ball lens 19 fixed to the portion. The ball lens 19 functions as an imaging lens between the LD chip 11 and a single mode optical fiber (not shown) that is inserted into the receptacle 5 and coupled thereto, and also forms an image between the optical fiber and the PD chip 10. Functions as a lens.

  Further, the stem 3 extends through the stem disk portion 20, the stem protrusion portion 21 that extends substantially perpendicularly from one surface of the stem disk portion 20, and on which the above-described micro BOSA chip 2 is mounted, and penetrates the stem disk portion 20. And a plurality of lead pins 22. The lead pin 22 includes a reception lead pin 22 and a transmission lead pin 22, and each lead pin 22 is connected to a corresponding component on the micro BOSA chip 2 by a bonding wire.

  The receptacle 5 is a connector for optically connecting the single mode optical fiber and the ball lens 19, and includes a cylindrical sleeve 23 that detachably accommodates the ferrule F of the single mode optical fiber, A flange portion 24 fixed to the end portion of the sleeve 23 and a fiber stub 25 made of, for example, zirconia ceramic provided in the through hole 5A at the center of the sleeve 23 and the flange portion 24 are provided. The fiber stub 25 has a long wavelength cut filter 25A at the end thereof, and has both functions of optical axis adjustment and optical connection.

  Next, the resin coating portion 30 provided between the can cap 4 and the receptacle 5 will be described with reference to FIGS. 1 and 2. The resin coating portion 30 is formed by injection molding a transparent resin, and covers the connecting portion 30 </ b> A provided in the gap portion 31 between the can cap 4 and the receptacle 5, and the outer peripheral surface 4 </ b> A of the can cap 4. An exterior portion 30B and an exterior portion 30C that covers the flange portion 24 of the receptacle 5 are configured.

  The reason why the connecting portion 30A of the resin coating portion 30 is provided in the gap portion 31 between the can cap 4 and the receptacle 5 is that the can cap 4 and the receptacle 5 are always held so that their axes are the same. Improvement of alignment, elimination of the influence of external humidity on the micro BOSA chip 2 by sealing the gap between the can cap 4 and the receptacle 5, and heat generated in the micro BOSA chip 2 is efficiently conducted to the outside and discharged. There is to do. In addition, in terms of discharging heat generated in the micro BOSA chip 2 to the outside, the resin generally has a higher thermal conductivity than air (for example, the thermal conductivity of air is 0.0241 [W / m · K], whereas the thermal conductivity of the resin is about 0.9 [W / m · K]). By utilizing this property, the heat generated by the micro BOSA chip 2 is efficiently transferred to the outside. It discharges well and takes measures against heat of the micro BOSA chip 2.

  The reason for providing the exterior portion 30B of the resin coating portion 30 so as to cover the outer peripheral surface 4A of the can cap 4 is to protect the can cap 4 from external impacts. The reason for providing the exterior portion 30C of the resin coating portion 30 so as to cover the flange portion 24 of the receptacle 5 is to protect the receptacle 5 from external impacts.

  The resin used for the resin coating 30 is a transparent resin so as not to hinder the light transmission between the can cap 4 and the receptacle 5. Specifically, acrylic resin, polyetherimide resin, polycarbonate resin or the like is used. And when an acrylic resin is used for transparent resin, especially high transparency and intensity | strength can be provided.

  Next, the process for providing the resin coating part 30 in the can cap 4 and the receptacle 5 is demonstrated with reference to FIGS.

[Step 1]
As shown in FIG. 5, a mold upper die 40 having a cavity 40A corresponding to the outer shape of the can cap 4 and the receptacle 5 is prepared, and an optical fiber ferrule is formed at the upper portion of the cavity 40A of the mold upper die 40 and at the center position. Place F. The upper mold 40 is formed in a half shape, and is configured to take out the molded product in the cavity 40A by being separated from each other at the end of the molding process. The mold upper mold 40 is formed with a resin injection hole 41 for filling the resin into the cavity 40A.

[Step 2]
As shown in FIG. 6, the ferrule F disposed in the cavity 40A in step 1 is positioned in the through hole 5A of the receptacle 5 inserted from the opposite side of the cavity 40A, and is attached to the receptacle 5.

[Step 3]
As shown in FIG. 7, the mold lower mold 42 is attached and fixed to the lower end portion 40 </ b> B of the mold upper mold 40. The mold upper mold 40 and the mold lower mold 42 form a pair, and are arranged so that the cavities 40A and 42A communicate with each other. The mold lower mold 42 is attached to the mold upper mold 40 so as to slide slightly in the direction of the arrow AB perpendicular to the axes of the cavities 40A and 42A.

[Step 4]
As shown in FIG. 8, the can cap 4 fixed to the stem 3 is inserted into the cavities 40 </ b> A and 42 </ b> A of the mold upper mold 40 and the mold lower mold 42 that are coupled to each other. The can cap 4 is inserted into the cavities 40A and 42A from the side opposite to the side where the ferrule F is disposed. Further, the can cap 4 inserted into the cavities 40A and 42A is adjusted in distance so that the image of light by the ball lens 19 is optimal with respect to the receptacle 5, and the mold lower mold 42 with respect to the mold upper mold 40. Is finely adjusted in the direction of the arrow AB perpendicular to the axes of the cavities 40A and 42A.

[Step 5]
A transparent resin such as an acrylic resin (or a polyetherimide resin or a polycarbonate resin) in the cavities 40A and 42A through a resin injection hole 41 provided in the mold upper mold 40 by an injection molding machine (not shown) as shown in FIG. As a result, the resin coating portion 30 including the connecting portion 30A and the exterior portions 30B and 30C is formed between the can cap 4 and the receptacle 5.

[Step 6]
As shown in FIG. 10, the mold upper mold 40 and the mold lower mold 42 are removed. When the mold upper mold 40 and the mold lower mold 42 are removed, a resin piece 30D having a resin injection hole 41 formed on the outside of the resin coating portion 30 is formed. This resin piece 30D is cut by a cutter or the like. Remove. Thus, the micro BOSA 1 shown in FIGS. 1 and 2 is completed.

  As described above in detail, in the micro BOSA 1 shown as the optical module in the present embodiment, the resin coating portion 30 made of a transparent resin is provided in the gap portion 31 located between the can cap 4 and the receptacle 5. By this resin coating portion 30, the receptacle 5 that supports the ferrule F of the optical fiber and the ball lens 19 of the can cap 4 can be fixed and held so as to be located on the same line. The can cap 4 and the receptacle 5 The optical signal can be transmitted and received between the two. In the micro BOSA 1, the gap between the can cap 4 and the receptacle 5 is sealed by the resin coating portion 30 in the gap portion 31 between the can cap 4 and the receptacle 5. Thus, even when used in a humid environment, the influence of the humidity can be prevented from reaching the micro BOSA chip 2 in the can cap 4. In the micro BOSA 1, the transparent resin filled in the gap 31 between the can cap 4 and the receptacle 5 generally has higher thermal conductivity than air. The heat generated in the micro BOSA chip 2 in the can cap 4 can be efficiently discharged to the receptacle 5 side. As a result, even when used in a high temperature environment, the operation of the micro BOSA chip 2 is hindered. Will not occur.

  That is, in the micro BOSA 1 shown as the optical module in the present embodiment, it is possible to prevent the alignment from being affected even when mounted on a moving body such as an airplane or a vehicle, and in a high-temperature / humid environment. Even when used below, it is possible to prevent the internal micro BOSA chip 2 from being affected, thereby improving the reliability during use.

  In the micro BOSA 1 shown as the optical module in the embodiment, the resin coating portion 30 covers the connecting portion 30A provided in the gap portion 31 between the can cap 4 and the receptacle 5 and the outer peripheral surface 4A of the can cap 4. Since it comprised from the exterior part 30B and the exterior part 30C which covers the flange part 24 of the receptacle 5, the alignment, thermal conductivity, and waterproofness which were mentioned above can be improved by the connection part 30A. Moreover, the outer cap 30B can protect the can cap 4 having the micro BOSA chip 2 from external impacts, and the outer cap 30C can protect the receptacle 5 holding the ferrule F from external impacts. it can. Further, the resin coating portion 30 including the connecting portion 30A and the exterior portions 30B and 30C can be used without additional arrangement of a special connecting tubular member for protecting the can cap 4 from an external impact. The resin cover 30 as a member can protect the can cap 4 and the receptacle 5 at the same time as well as improving the alignment, thermal conductivity, and waterproofing properties described above.

Further, in the micro BOSA 1 described above, when the transparent resin for forming the resin coating portion 30 as described above is formed of an acrylic resin, particularly high transparency and strength can be imparted, and the can cap 4 and the receptacle. 5 can transmit and receive optical signals without causing attenuation.
Moreover, when the transparent resin which forms the resin coating | coated part 30 as mentioned above is formed with polyetherimide resin, it is self-digestible, has high flame retardancy, has transparency, and has high mechanical strength. can do.
Moreover, when the transparent resin which forms the resin coating | coated part 30 as mentioned above is formed with a polycarbonate resin, there exists a merit that it is transparent, has high mechanical strength, and is inexpensive.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

The perspective view which shows micro BOSA which is an optical module which concerns on this invention Front view showing the appearance of the micro BOSA in FIG. A perspective view showing a micro BOSA chip which is an integrated optical circuit chip The perspective view which expanded the principal part of FIG. Front sectional view showing step 1 of the manufacturing method of the optical module Front sectional view showing step 2 of the method of manufacturing an optical module Front sectional view showing step 3 of the method of manufacturing the optical module Front sectional view showing step 4 of the method of manufacturing an optical module Front sectional view showing step 5 of the method of manufacturing an optical module Front sectional view showing step 6 of the method of manufacturing an optical module

Explanation of symbols

1 Micro BOSA (optical module)
2 Micro BOSA chip (integrated optical circuit chip)
3 Stem 4 Can cap 4A Outer peripheral surface 5 Receptacle 6 Tubular member for connection 10 PD chip (light receiving element)
11 LD chip (light emitting device)
19 ball lens 30 resin coating part 30A connecting part 30B exterior part 30C exterior part 31 gap part F ferrule 100 connector

Claims (5)

An integrated optical circuit chip on which the light emitting element and the light receiving element are mounted; a stem that supports the integrated optical circuit chip; and the hermetically sealed over the integrated optical circuit chip on the stem and optical with respect to the integrated optical circuit chip Of the optical fiber so that the ball lens and the optical fiber are optically coupled to the inside of the can cap provided with a ball lens so as to allow the optical coupling and the ball lens spaced apart from the can cap. A receptacle that holds a ferrule, and allows optical signals to be input and output bidirectionally between the optical fiber held by the receptacle and the element on the integrated optical circuit chip through the ball lens of the can cap. A module,
An optical module, wherein a resin coating portion made of a transparent resin is provided in a gap portion located between the can cap and the receptacle.   2. The optical module according to claim 1, wherein the resin coating portion includes a connecting portion formed in a gap portion between the can cap and the receptacle, and an exterior portion that covers an outer peripheral surface of the can cap and the receptacle. .   The optical module according to claim 1, wherein the transparent resin of the resin coating portion is an acrylic resin.   The optical module according to claim 1, wherein the transparent resin of the resin coating portion is a polyetherimide resin.   The optical module according to claim 1, wherein the transparent resin of the resin coating portion is a polycarbonate resin.

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