JP2004272061A - Optical communication module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical communication module that can be assembled while optical adjustments are simplified, and is more adaptive to faster optical communication at low cost. <P>SOLUTION: The optical communication module is an optical communication module which connects an optical fiber and an optical element 22, and equipped with an optical element substrate 20 where an optical element 22 having a microlens 24 formed on a light emission and a light reception surface is mounted, and a connection module 10 formed by molding in one body a coupling lens part 12 which optically couples the optical fiber and optical element 22, a sleeve part 11 which holds an end of the optical fiber so that it can be inserted and extracted on the optical axis 40 of the coupling lens 12 at one side of the coupling lens, and a holder part 13 which holds the optical element substrate 20 so that the microlens of the optical element 22 are positioned on the optical axis 40 on the other side of the coupling lens. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical communication module that performs optical communication using an optical fiber and an optical element, and more particularly, to an optical communication module that can simplify connection between an optical fiber and an optical element without lowering optical coupling efficiency. Regarding module improvement.
[0002]
[Prior art]
An optical communication system basically has a configuration in which a light emitting element that converts an electric signal into an optical signal and a light receiving element that converts an optical signal into an electric signal are connected to each other by an optical fiber. 2. Description of the Related Art An optical communication module (connector) that optically connects an optical element and an optical fiber to each other so that an optical element such as a light emitting element or a light receiving element can be attached to or detached from or inserted into an optical fiber can be used.
[0003]
Examples of such an optical communication module include, for example, JP-A-10-300994 (Patent Document 1), JP-A-7-134225 (Patent Document 2), and JP-A-7-294777 (Patent Document 3). Is mentioned.
[0004]
Patent Literature 1 discloses that a photoelectric element is incorporated into a device holder having a sleeve into which a ferrule connected to an end of an optical fiber is removably inserted, and the optical fiber and the photoelectric element are inserted when the ferrule is inserted into the sleeve. An optical connector in which optical coupling is ensured by a ball lens has been proposed.
[0005]
Patent Literature 2 proposes an integrated module in which a sleeve and a coupling lens are integrally formed of resin.
[0006]
Patent Document 3 aims to simplify the manufacturing process of an optical module and increase the communication speed, and has a fitting portion having a convex cross section and a bottomed hole into which an optical operating element is fitted on the upper surface of the fitting portion. Substrate, a fitted portion having a concave cross section fitted into the fitting portion, and a through-hole into which a fiber is inserted into the fitted portion, when the fitting portion and the fitted portion are fitted. Proposes an optical module in which the optical axis of an optical element positioned by being fitted into a bottomed hole and the optical axis of an optical fiber positioned by being inserted into a through-hole match.
[0007]
[Patent Document 1] JP-A-10-300994
[Patent Document 2] JP-A-7-134225
[Patent Document 3] JP-A-7-294777
[Problems to be solved by the invention]
However, the optical connector described in Patent Literature 1 needs to be assembled by adjusting the position of the light emitting element or the light receiving element mounted on the CAN (CAN) package with respect to the sleeve. In addition, since the sleeve and the spherical lens are composed of different parts, it is necessary to increase the coaxiality of each part, which increases the number of manufacturing steps, increases the manufacturing time, and increases the assembly cost.
[0008]
The integrated module described in Patent Literature 2 mounts a microball lens (ball lens) on an LED. However, this involves a complicated process and alignment adjustment, and thus requires a high manufacturing cost.
[0009]
The optical modules described in Patent Documents 1 to 3 use metal terminals (metal pins) for connecting an optical element to an external circuit, so that transmission loss increases in a high-frequency range and is not suitable for high-speed operation.
[0010]
In addition, since the characteristics of the laser diode change depending on changes in the ambient temperature and aging, it is necessary to monitor the amount of light emitted from the light emitting element even with a compact optical coupling element module to stabilize the amount of emitted light. Is desirable.
[0011]
Therefore, an object of the present invention is to provide an optical communication module that can be assembled with simplified optical adjustment.
[0012]
It is another object of the present invention to provide an optical communication module which can be coped with at a low cost and with higher speed of optical communication.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, an optical communication module according to the present invention is an optical communication module for connecting an optical fiber and an optical element, and an optical element substrate on which an optical element having a microlens formed on a light emitting or receiving surface is mounted. A coupling lens part for optically coupling the optical fiber and the optical element, a sleeve part for holding an end of the optical fiber on one side of the coupling lens so as to be able to be inserted and withdrawn on the optical axis of the coupling lens, and A connection module obtained by integrally molding a holder portion holding the optical element substrate so that the micro lens of the optical element is located on the optical axis on the other side of the coupling lens. I have.
[0014]
According to this configuration, since the microlens is formed directly on the light emitting or light receiving surface of the optical element, there is no need for a complicated assembly operation or alignment adjustment as compared with a case where a conventional microball lens is mounted, Since the optical communication module can be manufactured by a simple process, the cost of the optical communication module can be reduced. Further, by forming the microlenses, the optical coupling range between the optical fiber and the optical element can be expanded. Further, since the sleeve, the lens, and the optical element holder are integrally formed, the trouble of adjusting the axis of each component can be omitted, and the number of manufacturing steps is small, so that the assembly cost can be reduced.
[0015]
Further, an optical communication module of the present invention is an optical communication module for connecting an optical fiber and a light emitting element, wherein the light emitting element has a micro lens formed on a light emitting surface and a monitor capable of detecting light emitted from the light emitting element. An optical element substrate on which a light receiving element for mounting is mounted, extracting means for causing a part of light emitted from the light emitting element to be incident on the light receiving element for monitoring, and optically coupling the optical fiber and the light emitting element. A coupling lens portion, a sleeve portion for holding an end of the optical fiber on one side of the coupling lens so as to be able to be inserted and withdrawn on the optical axis of the coupling lens, and the microlens of the light emitting element coupling the optical element substrate to the microlens. The other side of the lens is held so as to be located on the optical axis, and the holder for holding the extracting means between the coupling lens and the light emitting element is integrally formed. It is characterized in that it comprises a becomes connected module.
[0016]
According to such a configuration, since the microlens is formed directly on the light emitting surface of the light emitting element, there is no need for a complicated assembly operation or alignment adjustment as compared with a case where a conventional microball lens is mounted, and a simpler operation is achieved. Since the optical communication module can be manufactured in a process, the cost of the optical communication module can be reduced. Further, by forming the microlenses, the optical coupling range between the optical fiber and the light emitting element can be expanded. Further, since the sleeve, the lens, and the optical element holder are integrally formed, the trouble of adjusting the axis of each component can be omitted, and the number of manufacturing steps is small, so that the assembly cost can be reduced. Further, since the change in the amount of light emitted from the light emitting element can be monitored by the output of the light receiving element, the amount of light emitted from the light emitting element can be controlled in accordance with the change in luminous efficiency.
[0017]
An optical communication module according to the present invention is an optical communication module for connecting an optical fiber and a light emitting element, wherein the light emitting element has a micro lens formed on a light emitting surface, and is formed integrally with the light emitting element to emit light from the light emitting element. An optical element substrate on which a light receiving element for monitoring capable of detecting emitted light is mounted, a coupling lens unit for optically coupling the optical fiber and the light emitting element, and an end of the optical fiber is connected to one side of the coupling lens. And a holder for holding the optical element substrate so that the microlens of the light emitting element is positioned on the optical axis on the other side of the coupling lens. And a connection module formed integrally with the connection module.
[0018]
According to such a configuration, since the microlens is formed directly on the light emitting surface of the light emitting element, there is no need for a complicated assembly operation or alignment adjustment as compared with a case where a conventional microball lens is mounted, and a simpler operation is achieved. Since the optical communication module can be manufactured in a process, the cost of the optical communication module can be reduced. Further, by forming the microlenses, the optical coupling range between the optical fiber and the light emitting element can be expanded. Further, since the sleeve, the lens, and the optical element holder are integrally formed, the trouble of adjusting the axis of each component can be omitted, and the number of manufacturing steps is small, so that the assembly cost can be reduced. Further, since the change in the amount of light emitted from the light emitting element can be monitored by the output of the light receiving element for monitoring, the amount of light emitted from the light emitting element can be controlled in accordance with the change in luminous efficiency. Further, since the light-emitting element and the monitoring light-receiving element for monitoring the amount of light emitted from the light-emitting element are integrally formed, the size of the optical communication module can be further reduced. In addition, since the light emitting element and the light receiving element for monitoring are integrally formed, the emitted light can be directly monitored, and the above-described extracting means is not required, so that the number of parts can be reduced, The labor at the time of assembly can also be reduced, and a lower cost optical communication module can be provided.
[0019]
The microlenses are preferably formed by a droplet discharge method. According to the droplet discharging method, it is possible to form a high-precision microlens by a simple process.
[0020]
It is preferable that the optical element or the light emitting element has a concave portion provided with a light emitting surface or a light receiving surface on a bottom portion, and the microlens is formed in the concave portion. By forming the microlenses in the concave portions, the microlenses can be more accurately and stably installed. This makes it possible to improve the optical coupling efficiency of the optical communication module.
[0021]
It is preferable that the optical element or the light emitting element has a convex portion on a light emitting surface or a light receiving surface, and the micro lens is formed on the convex portion. A microlens is formed by discharging a droplet of lens material on the upper surface of the convex part, so there is no need to perform special positioning, and the microlens is accurately and stably installed by the alignment accuracy when forming the convex part. can do. This makes it possible to easily form a microlens whose installation position is controlled with a high yield.
[0022]
Preferably, the optical element is a light receiving element, and a preamplifier circuit for amplifying an output of the light receiving element is further provided on the optical element substrate. With this configuration, the length of the wiring between the preamplifier circuit and the light receiving element can be reduced, and the attenuation of the detection signal can be reduced. Therefore, it is possible to amplify the output of the light receiving element in a state where the SN ratio is little deteriorated, so that a more accurate optical receiving module can be provided.
[0023]
It is preferable that at least one of the optical element, the light-emitting element, and the light-receiving element is covered with a gas-permeable or moisture-resistant resin. By coating with such a resin, high airtightness and moistureproofness can be maintained, and an optical element such as a light-emitting element or a light-receiving element can be protected from outside air and moisture, so that a more reliable communication module is provided. It is possible to do.
[0024]
It is preferable that the electric wiring formed on the optical element substrate and the external circuit are connected by a flexible wiring substrate having a microstrip line. According to such a configuration, signal loss in a high frequency range can be reduced, so that it is possible to provide an optical communication module compatible with high-speed driving. Further, since a flexible wiring board is used, the degree of freedom in design is improved.
[0025]
It is preferable that the electric wiring of the optical element substrate is formed by a microstrip line. According to such a configuration, signal loss in a high frequency range can be reduced, so that it is possible to provide an optical communication module compatible with high-speed driving.
[0026]
It is preferable that at least one of the optical element, the light emitting element, and the light receiving element is housed in a recess formed in the optical element substrate, and the inside of the recess is grounded. According to such a configuration, it is possible to shield an optical element such as a light emitting element or a light receiving element from external noise.
[0027]
It is preferable that at least one of the optical element, the light-emitting element, and the light-receiving element is housed in a concave portion formed in the optical element substrate, and the concave portion is embedded with a resin having air resistance or moisture resistance. By coating with such a resin, high airtightness and moistureproofness can be maintained, and an optical element such as a light emitting element or a light receiving element can be protected from outside air and moisture, so that a more reliable optical communication module can be provided. Can be provided.
[0028]
The optical element substrate may be formed of a laminate of first and second substrates having a step formed on the outer periphery and the concave portion formed on an upper portion, and may be attached to the holder using the step. preferable. According to this configuration, the positioning between the holder portion and the optical element substrate can be easily performed. Therefore, if the positional relationship between the optical axis of the connection module and the holder portion, and the positional relationship of the optical elements on the optical element substrate are accurately set in advance, the connection module can be easily connected to the holder by attaching the optical element substrate to the holder portion. The optical axis of the optical element can be adjusted. Therefore, the assembly can be performed in a simple process, and the cost can be reduced. Further, since the optical element substrate has a laminated structure, it is easy to provide wiring in an intermediate layer between the first and second substrates, and the degree of freedom in designing the optical element substrate is improved.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0030]
(1st Embodiment)
FIG. 1 is a cross-sectional view of the optical transmission module according to the first embodiment. FIG. 2 is a cross-sectional view illustrating a configuration of a VCSEL equipped with a microlens used in the optical transmission module according to the present embodiment. As shown in FIG. 1, the optical transmission module according to the present embodiment mainly includes a connection module 10 and a light emitting element substrate 20a.
[0031]
In the present embodiment, a case where a surface emitting light emitting element, specifically, a vertical cavity surface emitting laser (hereinafter, referred to as “VCSEL”) 22a is used as the light emitting element will be described.
[0032]
The connection module 10 includes a sleeve portion 11 in which an end of an optical fiber is held so as to be able to be inserted and withdrawn, a coupling lens portion 12 for allowing laser light emitted from a VCSEL 22a as a light emitting element to enter the optical fiber, and a light emitting element substrate 20a It is mainly constituted by a holder 13a for holding. The connection module 10 is integrally formed by injection molding a resin (eg, epoxy resin or the like) or an optical glass (eg, quartz glass, borosilicate glass, or the like) transparent to the wavelength of the laser light with a mold.
[0033]
The connection module 10 has a circular cross-section in the direction perpendicular to the optical axis 40 of the coupling lens unit 12, has open ends at both ends, mounts an optical fiber (not shown) from one end, and mounts an optical element substrate 20 a from the other end. It has a structure that can be used. A ferrule for holding and aligning the fiber may be connected to the tip of the optical fiber. One end of the connection module 10 is provided with a sleeve 11 into which an optical fiber or this ferrule can be inserted. The sleeve 11 has an abutment 14 formed by integral molding for defining the distance between the coupling lens 12 and the end of the optical fiber or ferrule.
[0034]
The other end of the connection module 10 is provided with a holder 13a on which the optical element substrate 20a can be mounted. At the end of the holder 13a, a step (abutting part) is formed for defining and fixing the position of the light emitting element substrate 20a. The light emitting element substrate 20a is adhesively fixed to the step so that the VCSEL 22a mounted on the light emitting element substrate 20a faces the coupling lens section 12. The holder 13a includes a unit for extracting a part of the light emitted from the light emitting element 22a, for example, a reflector 31.
[0035]
The light emitting element substrate 20a has a structure in which a VCSEL 22a is mounted on a stem. A microlens 24 is formed on the light emitting point of the VCSEL 22a so that the optical axes of the VCSEL 22a and the microlens 24 coincide. Further, the VCSEL 22a is mounted with high accuracy using an image recognition technique such that the optical axis is located at the center of the stem with reference to the outer peripheral portion of the circular light emitting element substrate 20a, for example.
[0036]
When the micro lens 24 is formed on the VCSEL 22a, the emission angle of the light emitted from the VCSEL 22a can be reduced, and the magnification of the coupling lens unit 12 is reduced as compared with the case where the micro lens 24 is not used. be able to. This makes it possible to increase the tolerance (tolerance) for optical coupling between the optical fiber, the coupling lens unit, and the light emitting element, and to expand the optical coupling range. Therefore, the tolerance of the dimensional accuracy of each component is increased as compared with the case where the microlens is not provided, so that the manufacturing process of the optical communication module can be simplified and the cost can be reduced. The structure of the VCSEL 22a on which the micro lens 24 is mounted will be described later in more detail.
[0037]
On the light emitting element substrate 20a, a light receiving element for monitoring (hereinafter, referred to as "monitor element") for monitoring light emitted from the VCSEL 22a and reflected by the reflection plate 31, for example, a monitor photodiode (hereinafter, "monitor PD") 25) are provided.
[0038]
That is, a part of the laser light emitted from the VCSEL 22a is reflected by the reflection plate 31 and enters the monitor PD 25. The monitor PD 25 generates a current value according to the amount of incident light. By monitoring this current value and controlling the VCSEL 22a in accordance with the change in the current value, the amount of light emitted from the VCSEL 22a is kept constant with respect to the change in the luminous efficiency of the VCSEL 22a due to a change in ambient temperature, a change over time, or the like. It becomes possible. Note that a preamplifier circuit (not shown) for converting the current from the monitor PD 25 into a voltage signal may be provided on the light emitting element substrate 20a.
[0039]
The electrode terminals (not shown) of the VCSEL 22a and the electrode terminals (not shown) of the monitor PD 25 are connected to the stem pins 23 by bonding wires 26, and are electrically connected to an external circuit via the stem pins 23. I have. The operation of the VCSEL 22a and the monitor PD 25 is controlled by this external circuit.
[0040]
Hereinafter, the structure of the VCSEL 22a on which the microlens 24 is mounted will be specifically described with reference to FIG.
[0041]
As shown in the figure, the VCSEL 22a mainly includes a semiconductor substrate 101 and a vertical resonator (hereinafter referred to as “resonator”) 140 provided on the semiconductor substrate 101.
[0042]
The resonator 140 mainly includes an n-type DBR mirror (hereinafter, referred to as a “lower mirror”) 102 partially having a protrusion, and a columnar portion 130 provided on the protrusion of the lower mirror 102.
[0043]
The columnar portion 130 includes a part (projection) of the lower mirror 102, an active layer 103, and a p-type DBR mirror 104 (hereinafter, referred to as “upper mirror”).
[0044]
An insulating layer 106 constituting the bank portion 110 is formed around the protruding portion of the lower mirror 102, and a concave portion 112 is formed by the insulating layer 106 and the upper surface of the columnar portion 130. Here, the bank portion 110 is a region around the columnar portion 130 and includes the insulating layer 106 and the first electrode 107 provided on the upper surface 106c of the insulating layer 106.
[0045]
A first electrode 107 is formed in the recess 112 and on the upper surface 106c of the insulating layer 106. The microlens 24 is disposed in the recess 112 via the first electrode 107. Further, the first electrode 107 is provided with a hole for allowing the laser light emitted from the VCSEL 22a to pass therethrough.
[0046]
The light-emitting surface 108 of the VCSEL 22a is provided at the bottom of the concave portion 112 (the upper surface of the columnar portion 130). The laser light emitted from the light emitting surface 108 passes through the hole provided in the first electrode 107, passes through the microlens 24, and is emitted to the outside.
[0047]
The distance X between the upper edge 110a of the bank 110 and the light emitting surface 108 is preferably 0.5 μm or more. By forming in this manner, it becomes possible to install the microlenses 24 on the light emitting surface 108 in a more stable state. In addition, it is desirable that the upper surface 110b of the bank section 110 be formed at a position higher than the light emitting surface 108. Thereby, the microlens 24 can be set on the light emitting surface 108 in a more stable state. Here, the upper edge 110 a of the bank 110 refers to an edge of the upper surface 110 b of the bank 110 on the side closer to the columnar portion 130.
[0048]
The microlens 24 is formed by discharging a lens material into the recess 112 by, for example, a droplet discharging method. As a droplet discharging method, a conventionally known method is used, and a so-called thermal inkjet method or a piezo method may be used. From the viewpoint of pressure controllability, a piezo method is desirable.
[0049]
According to the droplet discharge method, when the droplet (lens material) discharged from the nozzle of the droplet discharge head lands in the concave portion 112, it is deformed to be centered in the concave portion 112 by surface tension. The position is automatically corrected. The discharged droplet has a shape and a size corresponding to the shape and size of the concave portion, the discharge amount and surface tension of the lens material, and the interfacial tension between the inner surface of the concave portion and the lens material. Therefore, by controlling these, the shape and size of the microlens 24 (see FIG. 2) can be controlled, and a microlens having a desired radius of curvature, shape, and size can be easily manufactured by a simple process. And the degree of freedom in lens design is increased. Further, as compared with a module equipped with a conventional microball lens, a complicated assembly process and a centering operation are not required, so that the cost of the optical transmission module can be further reduced.
[0050]
If necessary, before forming the microlenses 24, (i) a method of forming a thin film with a liquid-repellent material (eg, fluoroalkylsilane (FAS) or the like) in the recess 112; ii) A treatment for adjusting the wetting angle of the microlens may be performed by a method of modifying the surface by performing a plasma treatment. Through these processes, the size and shape of the lens can be more precisely controlled.
[0051]
Next, each component of the VCSEL 22a will be described in more detail.
[0052]
The VCSEL 22a includes a semiconductor substrate 101 made of n-type GaAs, and a resonator 140 formed on the semiconductor substrate 101.
[0053]
The resonator 140 is configured by sequentially stacking the lower mirror 102, the active layer 103, and the upper mirror 104.
[0054]
The lower mirror 102 is made of, for example, n-type Al _0.9 Ga _0.1 As layer and n-type Al _0.15 Ga _0.85 An active layer 103 is, for example, a GaAs well layer and an Al layer. _0.3 Ga _0.7 The upper mirror 104 is formed of a p-type Al barrier layer and includes a quantum well structure in which a well layer is formed of three layers. _0.9 Ga _0.1 As layer and p-type Al _0.15 Ga _0.85 It is a DBR mirror of 25 pairs in which As layers are alternately stacked. The lower mirror 102, the active layer 103, and the upper mirror 104 form a pin diode. Note that the composition and the number of layers constituting the lower mirror 102, the active layer 103, and the upper mirror 104 are not limited thereto.
[0055]
A ring-shaped current constriction layer 105 made of aluminum oxide (having a concentric cross section when cut along a plane parallel to the XY plane in FIG. 2) in a region near the active layer 103 among the layers constituting the upper mirror 104. Is formed.
[0056]
The first electrode 107 is formed on the upper surface of the columnar portion 130 and the upper surface of the insulating layer 106, and the second electrode 109 is formed on the back surface of the semiconductor substrate 101 (the surface opposite to the surface on which the resonator 140 is installed). The first electrode 107 is made of, for example, a stacked film of an alloy of Au and Zn and Au. The second electrode 109 is made of, for example, a laminated film of an alloy of Au and Ge and Au. In the VCSEL 22 a, the first electrode 107 is bonded on the columnar portion 130 and the second electrode 109 is bonded on the back surface of the semiconductor substrate 101, and current is injected into the active layer 103 by the first electrode 107 and the second electrode 109. Is done. Note that the material for forming the first and second electrodes 107 and 109 is not limited to the above. As a material for forming the insulating layer 106, from the viewpoint of heat resistance, a polyimide resin, a fluorine-based resin, an acrylic resin, an epoxy resin, or the like is desirable. A system resin is desirable.
[0057]
An example of the operation of the VCSEL 22a used in the present embodiment will be described below.
[0058]
First, when a forward voltage is applied to the pin diode between the first electrode 107 and the second electrode 109, recombination of electrons and holes occurs in the active layer 103, and light emission occurs. Stimulated emission occurs when the generated light reciprocates between the upper mirror 104 and the lower mirror 102, and the light intensity is amplified. When the optical gain exceeds the optical loss, laser oscillation occurs, laser light is emitted from the light emitting surface 108 on the upper surface of the columnar portion 130, and is formed on the light emitting surface 108 in the recess 112 (the area inside the bank 110). Incident on the microlens 24. The laser beam incident on the microlens 24 is emitted in the direction perpendicular to the semiconductor substrate 101 (Z direction shown in FIG. 2) after the radiation angle is adjusted by the microlens 24.
[0059]
According to the above configuration, since the microlens is formed on the optical element, it is possible to provide an optical communication module having an enlarged optical coupling range. Further, since the sleeve portion, the coupling lens portion and the holder portion are integrally formed, the trouble of adjusting the axis of each component can be omitted, and the number of manufacturing steps can be reduced, so that the assembly cost can be reduced. Further, since the amount of light emitted from the light emitting element can be monitored by the output of the monitor element, the amount of light emitted from the light emitting element can be controlled according to a change in luminous efficiency.
[0060]
Further, since the microlenses are formed by using the droplet discharging method, the droplets can be discharged to more accurate positions, and the microlenses whose installation positions are controlled can be formed easily and with high yield. Further, since the microlenses are formed in the recesses (the area inside the bank) by the droplet discharging method, the microlenses can be accurately and stably installed. This makes it possible to effectively control the characteristics of the emitted light (e.g., radiation angle and the like), and to improve the optical coupling efficiency between the light emitting element and the optical fiber. In addition, since the upper edge of the bank is higher than the light-emitting surface, alignment when forming the microlens is facilitated, and manufacturing can be performed with a high yield. Further, since the amount of the lens material introduced can be easily controlled, the size and shape of the lens can be controlled.
[0061]
(Second embodiment)
FIG. 3 is a cross-sectional view schematically showing a VCSEL 22b on which a microlens used in the optical transmission module according to the second embodiment is mounted. The optical communication module according to the present embodiment has the same configuration as the optical communication module according to the first embodiment except that a light emitting element in which a microlens is formed on a convex portion provided on the light emitting surface 108 is used. Having. In the figure, components having substantially the same functions as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0062]
As shown in FIG. 3, the surface-emitting type semiconductor laser 22b according to the present embodiment includes a light-emitting surface 108 from which light is emitted, a convex portion (hereinafter, referred to as a base member 120) provided on the light-emitting surface 108, and a base. And a micro lens 24 provided on the upper surface 120a of the member 120. A first electrode 107 having an opening is formed on the upper surface of the columnar portion 130 and the insulating layer 106, and laser light is emitted from the light emitting surface 108 through the opening. The laser light emitted from the light emitting surface 108 further enters the microlens 24, is collected by the microlens 24, and is emitted to the outside.
[0063]
The base member 120 may be formed of a material that allows light of a predetermined wavelength emitted from the light emitting surface 108 to pass therethrough. Such a base member 120 can be formed from, for example, a polyimide resin, an acrylic resin, an epoxy resin, or a fluorine resin. Further, the base member 120 may be a semiconductor layer.
[0064]
Although the three-dimensional shape of the base member 120 is not particularly limited, it is necessary that the base member 120 has a structure capable of mounting the microlens 24 on at least the upper surface thereof. The height of the base member 120 is determined by the shape and size of the microlenses 24 formed on the upper surface 120a of the base member 120. Specifically, the height h of the base member 120 is determined depending on the radius of curvature r of the microlens 24 and the distance d from the light emitting surface 108 to the vertex of the lens 24 (see FIG. 3).
[0065]
For example, when the refractive index of the base member 120 is substantially equal to the refractive index of the microlens 24, in order for the microlens 24 to function as a lens, the radius of curvature r of the microlens 24 and the vertex of the lens from the light emitting surface 108 A relationship that satisfies the following equation (1) needs to be established with the distance d (see FIG. 3).
[0066]
r ≦ 0.34 × d (1)
The radius of curvature r of the microlens 24 and the height h of the base member 120 are determined so as to satisfy the expression (1). In this case, when r = 0.34 × d is satisfied, the light emitted from the microlens 24 is a collimated light.
[0067]
Generally, the longer the distance d from the light emitting surface 108 to the vertex of the lens and the smaller the radius of curvature r of the lens, the greater the light condensing function of the lens.
[0068]
Further, by controlling the shape of the upper surface 120a of the base member 120, the shape of the microlens 24 can be controlled. For example, in the VCSEL 22b (see FIG. 3), the shape of the upper surface 120a of the base member 120 is a circle. When the shape of the upper surface of the base member is a circle, the three-dimensional shape of the microlens can be formed into a spherical shape or a cut spherical shape.
[0069]
Specifically, the microlens 24 discharges a droplet 24a made of a lens material onto the upper surface 120a of the base member 120 by a droplet discharging method to form a microlens precursor, and then forms the microlens precursor. It is formed by curing the body. The material and the specific manufacturing method of the microlens 24 are the same as those described in the first embodiment.
[0070]
According to the present embodiment, in addition to the effects described in the first embodiment, since the microlenses are further provided on the upper surface of the base member, the optical path length of the light emitted from the light emitting surface 108 (light emitting surface From the lens to the microlens) can be secured. Therefore, the light collecting function of the microlens can be enhanced.
[0071]
In general, it is difficult to precisely control the landing position of a droplet at the time of discharging the droplet. However, according to the present embodiment, the droplet (lens material) is formed by discharging the droplet (lens material) on the upper surface of the base member. In particular, a microlens can be formed without performing positioning. Therefore, the microlens can be formed with the alignment accuracy at the time of forming the base member, and the microlens whose installation position is controlled can be formed easily and with high yield.
[0072]
(Third embodiment)
FIG. 4 is a sectional view of the optical transmission module according to the third embodiment. FIG. 5 is an enlarged cross-sectional view of the monitor PD integrated VCSEL 22c used in the optical transmission module according to the third embodiment. In each of the drawings, components having substantially the same functions as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0073]
The optical transmission module according to the third embodiment uses a monitor PD integrated VCSEL 22c having a laminated structure in which a VCSEL 302 and a monitor PD 301 are integrally formed as a light emitting element and a monitor element, and a convex portion is provided on the monitor PD integrated VCSEL 22c. The optical transmission module of the first embodiment has the same structure as that of the first embodiment except that a base member 120 is provided and a micro lens is formed on the base member 120.
[0074]
As shown in FIG. 5, the monitor PD integrated VCSEL 22c has a structure in which a monitor PD layer 301 is laminated on a VCSEL layer 302.
[0075]
In the VCSEL layer 302, an n-type DBR mirror (lower mirror) 102, an active layer 103, a current confinement layer 105, a p-type DBR mirror (upper mirror) 104, and a p-type contact layer 311 are sequentially stacked on a semiconductor substrate 101. It has a structure (hereinafter, referred to as a resonator 140). The configuration of the VCSEL layer 302 is the same as that of the first embodiment except that the VCSEL layer 302 has a p-type contact layer in the uppermost layer. The p-type contact layer 311 is, for example, a p-type _0.15 Ga _0.85 It consists of an As layer.
[0076]
On the semiconductor substrate 101, an insulating layer 106 is formed around the resonator 140. A VCSEL anode electrode 107 is formed in a strip shape on the insulating layer 106, and one end of the VCSEL anode electrode 107 is provided so as to be in contact with a P-type contact layer 311 constituting the resonator 140 to form an ohmic contact. At the other end, an electrode pad for connection to a stem pin is formed by a bonding wire. A belt-shaped VCSEL cathode electrode 109 is further formed on the insulating layer 106, and one end of the VCSEL cathode electrode 109 is in contact with the semiconductor substrate 101 on a part of the insulating layer 106 to form an ohmic contact. Thus, the opening 325 is provided.
[0077]
The VCSEL anode electrode 107 is formed of, for example, chromium and a gold-zinc alloy. The VCSEL cathode electrode 109 is formed of, for example, a gold-germanium alloy.
[0078]
The monitor PD layer 301 is formed on the VCSEL layer 302. The monitor PD layer 301 includes an n-type contact layer 312, a light absorption layer 313, and a p-type contact layer 314.
[0079]
The n-type contact layer 312 is made of, for example, n-type Al _0.15 Ga _0.85 It consists of an As layer. The light absorption layer 313 is made of, for example, a GaAs layer. The p-type contact layer 314 is made of, for example, p-type Al _0.15 Ga _0.85 It consists of an As layer.
[0080]
The PD cathode electrode 315 forms an ohmic contact with the n-type contact layer 312. The PD cathode electrode 315 is partially in contact with the VCSEL anode electrode 107, and the VCSEL anode electrode 107 and the PD cathode electrode 315 form a common electrode. On the VCSEL layer 302, an insulating layer 317 is provided adjacent to the monitor PD layer 301. A PD anode electrode 316 is formed on the insulating layer 317 and the p-type contact layer 314, and the PD anode electrode 316 forms an ohmic contact with the p-type contact layer 314. In the PD anode electrode 316, a portion serving as a laser emission port is partially removed in a circular shape, and the p-type contact layer 314 is exposed from the circular portion.
[0081]
Between the PD cathode electrode 315 and the PD anode electrode 316, an external circuit for detecting a current generated by photoelectric conversion by the photodiode (monitor PD layer 301) is connected. This external circuit is further connected to a control device for controlling the drive current of the VCSEL (VCSEL layer 302), and the control device controls the drive current of the VCSEL according to the current detection value of the external circuit. .
[0082]
Specifically, a laser is oscillated from the upper mirror 104 by applying a predetermined voltage between the VCSEL anode electrode 107 and the VCSEL cathode electrode 109 and flowing a current through the active layer 103. This laser light is incident on the monitor PD layer 301 from the p-type contact layer 311. Simultaneously with the laser oscillation, a reverse bias voltage is applied between the n-type contact layer 312 and the p-type contact layer 314 of the monitor PD layer 301 to make the light absorption layer 313 a depletion layer. Part of the incident light is absorbed by the depletion layer and converted into a current. This current is detected by an external circuit connected between the PD cathode electrode 315 and the PD anode electrode 316. The control device operates according to the current detection value of the external circuit, and the drive current of the VCSEL is controlled.
[0083]
The laser light that has not been absorbed by the depletion layer of the photodiode passes through the p-type contact layer 314 and is emitted from the light emitting surface 108 (the opening formed in the PD anode electrode 316).
[0084]
The light absorption rate of laser light by the photodiode is mainly determined by the thickness and the absorption coefficient of the light absorption layer 313. Therefore, by appropriately selecting the thickness of the light absorption layer 313 and the value of the absorption coefficient, the light absorptivity of the laser output by the photodiode can be adjusted.
[0085]
A base member 120 (convex portion) is formed on the light emitting point of the monitor PD integrated VCSEL 22c, and a microlens 24 is formed thereon by, for example, a droplet discharge method. The laser light emitted from the light emitting surface 108 passes through the base member 120, is collected by the microlens 24, and is emitted to the outside.
[0086]
In the present embodiment, a convex portion is formed on the light emitting surface of the monitor PD integrated VCSEL 22c, and a microlens is formed thereon. However, as in the first embodiment, a concave portion is formed. A micro lens may be formed in the recess.
[0087]
Further, a preamplifier circuit (not shown) for converting a current from the monitor PD layer 301 into a voltage signal may be provided on the light emitting element substrate 20a.
[0088]
According to such a configuration, by using the monitor PD integrated type VCSEL 22c, the emitted light emitted from the light emitting element can be directly incident on the light receiving element without using another intermediary means (reflection plate). Can be reduced, and the assembling labor involved in installing other intermediary means can be reduced, so that a lower cost optical transmission module can be provided. Further, since the means for detecting a change in the amount of laser light and the light emitting element are integrally formed, the optical communication module can be made more compact.
[0089]
(Fourth embodiment)
FIG. 6 is a sectional view illustrating an optical receiving module according to the fourth embodiment. The fourth embodiment has the same structure as the first embodiment except that a light receiving element substrate 20b is attached to the connection module 10 instead of the light emitting element substrate 20a and a preamplifier 27 is mounted. In the figure, components having substantially the same functions as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0090]
The light receiving element substrate 20b has a structure in which a photodiode (PD) 22d as a light receiving element is mounted on a stem. In addition, it is preferable that a preamplifier circuit 27 for converting a current from the PD 22d into a voltage signal be provided on the light receiving element substrate 20b. The micro lens 24 is formed on the light receiving surface of the PD 22d such that the optical axes of the PD 22d and the micro lens 24 match. The PD 22d is positioned and mounted on the light receiving element substrate 20b with high precision using an image recognition technique so that its optical axis is centered on the basis of the outer periphery of the circular light receiving element substrate 20b. . The micro lens 24 is formed on the PD 22d by, for example, an inkjet method. An electrode terminal (not shown) of the PD 22d and an electrode terminal (not shown) of the preamplifier circuit 27 are connected to the stem pin 23 by a bonding wire 26, and are electrically connected to an external circuit.
[0091]
According to the above configuration, the wiring length between the preamplifier circuit and the light receiving element can be reduced, and the attenuation of the detection signal can be reduced as much as possible. Therefore, it is possible to amplify the output of the light receiving element in a state where the SN ratio is little degraded, so that a more accurate optical communication module can be provided. Further, since the microlens is formed on the light receiving element, it is possible to provide an optical receiving module having an enlarged optical coupling range. Further, since the sleeve portion, the coupling lens portion and the holder portion are integrally formed, the trouble of adjusting the axis of each component can be omitted, and the number of manufacturing steps can be reduced, so that the assembly cost can be reduced. In addition, by forming a microlens by a droplet discharging method, a high-precision microlens can be formed by a simple process. Therefore, an accurate and inexpensive optical receiving module can be provided.
[0092]
(Fifth embodiment)
FIG. 7 is a cross-sectional view illustrating a light-emitting element substrate 20a according to the fifth embodiment. As shown in FIG. 7, in the fifth embodiment, the VCSEL 22a is disposed on the monitor PD 25 in the light emitting element substrate 20a, and the VCSEL 22a and the monitor PD 25 are respectively provided except for a portion of the microlens 24 from which light is emitted. It has a structure embedded with a mold resin 29 having low air permeability and low moisture permeability. The mold resin 29 is preferably made of a transparent resin in order to cover the light receiving surface of the monitor PD 25 that receives a part of the light emitted from the VCSEL 22a. For example, an epoxy resin may be used as such a resin. it can.
[0093]
In the present embodiment, the VCSEL 22a is stacked on the monitor PD 25, but the VCSEL 22a and the monitor PD may be arranged on the same plane as in the first embodiment.
[0094]
In the case of using the monitor PD integrated type VCSEL as in the second embodiment, there is no need to receive light from the outside, so that the molding resin 29 does not need to be made of a transparent resin and is made of an opaque resin. Even a resin can be used.
[0095]
Further, in the above example, the light emitting element substrate 20a has been described, but the same effect can be obtained by adopting a similar configuration in the light receiving element substrate 20b of the fourth embodiment. That is, specifically, in the light receiving element substrate 20b, a resin material may be used for the connection module 10 by covering the PD 22d and the preamplifier 27 with the mold resin 29 except for the part where the light of the microlens is incident. Also in this case, the mold resin 29 does not need to be transparent.
[0096]
With such a configuration, even when a resin material is used for the connection module 10, it is possible to protect optical elements such as a light emitting element and a light receiving element from the outside air and moisture, and to provide a highly reliable optical communication module. obtain.
[0097]
(Sixth embodiment)
FIG. 8 is a perspective view for explaining a light emitting element substrate used in the sixth embodiment, and FIG. 9 is a cross-sectional view in the AA ′ direction of FIG. FIG. 10 is a diagram for explaining an optical communication module according to the sixth embodiment.
[0098]
The light emitting element substrate 60 used in the sixth embodiment mainly includes an upper substrate 63 as a first substrate and a lower substrate 61 as a second substrate. The monitor PD integrated VCSEL 22e is mounted in a range defined by a through hole 64 provided in the upper substrate 63 on the lower substrate 61.
[0099]
The lower substrate 61 and the upper substrate 63 are formed of an insulating substrate formed of, for example, ceramic or resin. Since two substrates are used in this manner, wiring can be easily formed in an intermediate layer of the substrate, and the degree of freedom in designing a light emitting element substrate is improved.
[0100]
A ground pattern 62 for grounding a predetermined pattern is formed on the lower substrate 61 by a metal thin film, and an upper substrate 63 is laminated thereon.
[0101]
On the upper substrate 63, signal wires (electric wires) 66b and 66c connected to the anode electrode and the cathode electrode of the VCSEL layer forming the monitor PD integrated VCSEL 22e, and the anode of the monitor PD layer forming the monitor PD integrated VCSEL 22e. Signal wirings 66a and 66d connected to the electrodes and the cathode electrode, and a ground pattern 66e connected to the ground pattern 62 on the lower substrate 61 are formed. These signal wires 66a to 66d on the upper substrate 63 are formed by microstrip lines. Further, the signal wirings 66a to 66d and the ground pattern 66e are connected to the signal wirings 66a 'to 66d' and the ground pattern 66e 'on the flexible wiring board 67, and are connected to an external circuit (not shown). The signal wiring on the flexible wiring board 67 also realizes a microstrip line. Among these signal lines, the signal lines 66b, 66c and 66b ', 66c' connected to the anode electrode and the cathode electrode of the VCSEL layer are particularly designed to transmit high-frequency signals to the VCSEL layer with low loss. , The characteristic impedance of the microstrip line is designed, thereby enabling high-speed modulation driving of the VCSEL. The flexible circuit board 67 can be used to match an external circuit with a circuit on the upper board 63 side. The signal wires 66a to 66d connected to the anode electrode and the cathode electrode of the VCSEL and the monitor PD are formed of a metal thin film. The ground pattern 62 on the lower substrate 61 and the ground pattern 66e on the upper substrate are connected by a wiring 68 formed on a side wall of the upper substrate. The ground pattern 66e formed on the upper substrate 63 is formed so as to surround the periphery of the monitor PD integrated VCSEL 22e, thereby keeping the electric field around the VCSEL (optical element) constant and enhancing the noise shield. This makes it possible to suppress the influence of external noise.
[0102]
The monitor PD integrated VCSEL 22 e is arranged at a predetermined position in the through hole 64 of the upper substrate 63 on the lower substrate 61, and each electrode terminal (not shown) is connected to the signal wiring of the upper substrate 63 by the bonding wire 26. The connection pads 66a to 66d are connected. Here, the monitor PD integrated VCSEL 22e is different from the monitor integrated VCSEL of the third embodiment in that the anode electrode and the cathode electrode of the VCSEL, and the anode electrode and the cathode electrode of the monitor PD are formed independently. However, other configurations are the same.
[0103]
As described above, since the wiring from the external circuit to the VCSEL is formed with a predetermined characteristic impedance, a drive signal (not shown) from the external drive circuit can be transmitted to the VCSEL with low loss, so that a higher-speed VCSEL can be used. Driving becomes possible.
[0104]
A microlens 24 formed by a droplet discharge method is mounted on the monitor PD integrated VCSEL 22e. The micro lens 24 may be provided on a convex portion (base member) formed on the light emitting surface of the monitor PD integrated VCSEL 22e, similarly to the third embodiment, or provided on the monitor PD integrated VCSEL 22e. It may be provided in a recess having a light emitting surface at the bottom provided. The monitor PD-integrated VCSEL 22 e and the microlens 24 are covered with a mold resin 65 except for a part of the microlens 24 (a part from which light is emitted). Thereby, the influence of moisture, air, and the like on the monitor PD and VCSEL can be reduced, and airtightness can be ensured. Further, the monitor PD integrated VCSEL 22e is placed in the through hole 64 of the upper substrate, and is surrounded by a wall composed of the upper substrate 63. The amount can be easily adjusted. Therefore, it is possible to accurately manufacture the light emitting element substrate by a simple process.
[0105]
Further, the light emitting element substrate 60 includes an upper substrate 63 and a lower substrate 61 having different sizes, and a step may be formed on the outer periphery of the upper substrate 63. By utilizing this step, it is possible to easily attach the optical fiber to the holder of the module for connecting the optical fiber. The optical element substrate according to the present embodiment is combined with the connection module 10 in which the sleeve, the coupling lens, and the holder are integrally formed.
[0106]
FIG. 10 shows an example in which the optical element substrate 60 according to the present embodiment and the connection module 10 are combined.
[0107]
The holder portion 13b of the connection module 10 is formed so as to match a step formed on three surfaces by the upper substrate 63 and the lower substrate 61 constituting the optical element substrate 60. Specifically, the holder portion 13b has a structure capable of fitting to the side walls 70a, 70b, 70c of the upper substrate 63 of the light emitting element substrate 60, and the connection is established by the three surfaces 70a, 70b, 70c. The module 10 and the optical element substrate 60 are positioned. The holder section 13b has a partly open surface except for contacting the side walls 70a, 70b, 70c, and the terminals of the signal wirings 66a to 66d formed on the upper substrate 63 are connected to the flexible wiring substrate 67. Exposed as possible. Since the flexible wiring board 67 can be connected to the exposed terminals as described above, there is no fear of disconnection of the flexible wiring board 67 even when the optical element substrate 60 is fitted to the connection module 10.
[0108]
Also, in the above example, an example in which the monitor PD integrated VCSEL is mounted so that the light emitting surface faces free space has been described. However, the monitor PD integrated VCSEL is formed by flip chip bonding with the light emitting surface facing the lower substrate side. May be mounted. In this case, the monitor PD-integrated VCSEL can be connected to the signal wiring on the substrate without being connected by wire bonding, so that it is possible to provide an optical transmission module corresponding to higher speed. Also in this case, a microstrip line can be formed by forming a signal wiring pattern between two substrates and forming a ground pattern on the outer surface of one substrate. By forming a microstrip line, it is possible to reduce transmission loss in a high frequency range. In addition, since the laser light emitted from the light emitting element is emitted through the lower substrate, the lower substrate is formed of a light-transmitting material or a laser light when no light-transmitting material is used. A through-hole through which light passes is formed.
[0109]
In the present embodiment, the light emitting element substrate including the monitor PD integrated VCSEL has been described, but another light emitting element or light receiving element may be mounted.
[0110]
According to the above configuration, since a flexible substrate having a microstrip line is used without using a metal pin for connection to an external circuit, it is possible to cope with a further increase in the speed of optical communication. Also, by forming the optical element in the hole of the upper substrate, it is possible to easily adjust the liquid amount of the mold resin covering the optical element, and it is possible to simplify the manufacturing process, thereby reducing the cost. Can be achieved. Further, since the optical element substrate has a step on the outer periphery, the optical element substrate can be easily attached to the holder of the module for connecting to the optical fiber by using the step. Therefore, if the positional relationship between the optical axis of the connection module and the holder portion, and the positional relationship of the optical elements on the optical element substrate are accurately set in advance, the connection module can be easily connected to the holder by attaching the optical element substrate to the holder portion. The optical axis of the optical element can be adjusted. In addition, since the optical element substrate has a laminated structure, a wiring layer can be easily provided between the upper and lower substrates, and the degree of freedom in designing the optical element substrate is improved.
[0111]
Therefore, by using the optical element substrate of the present embodiment, it is possible to provide an optical communication module which can cope with high speed, has high reliability, is accurate, and is low in cost.
[0112]
Note that the present invention is not limited to the contents of the above-described embodiment, and various modifications can be made within the scope of the present invention. Therefore, for example, various configurations other than the above-described embodiment can be applied to the configuration of each optical element (VCSEL and monitor element), the wiring of the substrate, and the like.
[Brief description of the drawings]
FIG. 1 is a sectional view of an optical transmission module according to a first embodiment.
FIG. 2 is a cross-sectional view illustrating a configuration of a VCSEL equipped with a microlens used in the optical transmission module according to the first embodiment.
FIG. 3 is a cross-sectional view schematically illustrating a VCSEL equipped with a microlens used in an optical transmission module according to a second embodiment.
FIG. 4 is a cross-sectional view of an optical transmission module according to a third embodiment.
FIG. 5 is an enlarged cross-sectional view of a monitor PD integrated VCSEL used for an optical transmission module according to a third embodiment.
FIG. 6 is a cross-sectional view illustrating an optical receiving module used in a fourth embodiment.
FIG. 7 is a cross-sectional view illustrating a light emitting element substrate used in a fifth embodiment.
FIG. 8 is a perspective view illustrating a light emitting element substrate used in a sixth embodiment.
FIG. 9 is a cross-sectional view in the AA ′ direction of FIG. 8;
FIG. 10 is a diagram for explaining an optical communication module according to a sixth embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Connection module, 20a ... Light emitting element board, 22a ... Vertical cavity surface emitting laser (VCSEL), 23 ... Stem pin, 24 ... Micro lens, 25 ... Monitor photodiode (Monitor PD), 26: bonding wire, 27: preamplifier circuit, 29: mold resin, 31: reflector, 40: optical axis, 60: light emitting element substrate, 61 ..Lower substrate, 62 ground pattern, 63 upper substrate, 64 hole, 65 mold resin, 66a-d wiring pattern, 66e ground pattern, 67 ... Flexible substrates

Claims (13)

An optical communication module for connecting an optical fiber and an optical element,
An optical element substrate on which an optical element having a microlens formed on a light emitting or receiving surface is mounted,
A coupling lens part for optically coupling the optical fiber and the optical element, a sleeve part for holding an end of the optical fiber on one side of the coupling lens so as to be able to be inserted and withdrawn on the optical axis of the coupling lens, and the optical element A connection module obtained by integrally molding a holder portion that holds the optical element substrate so that the microlens is positioned on the optical axis on the other side of the coupling lens;
Optical communication module provided with. An optical communication module for connecting an optical fiber and a light emitting element,
An optical element substrate on which a light-emitting element having a microlens formed on a light-emitting surface and a light-receiving element for monitoring capable of detecting light emitted from the light-emitting element are mounted;
Extraction means for causing a part of the light emitted from the light emitting element to enter the monitor light receiving element,
A coupling lens portion for optically coupling the optical fiber and the light emitting element, a sleeve portion for holding an end of the optical fiber on one side of the coupling lens so as to be able to be inserted and withdrawn on the optical axis of the coupling lens, and the optical element The substrate is held so that the microlens of the light emitting element is positioned on the optical axis on the other side of the coupling lens, and the holder unit that holds the extracting means between the coupling lens unit and the light emitting element is integrally formed. A molded connection module,
Optical communication module provided with. An optical communication module for connecting an optical fiber and a light emitting element,
An optical element substrate on which a light emitting element having a micro lens formed on a light emitting surface and a light receiving element for monitoring formed integrally with the light emitting element and capable of detecting light emitted from the light emitting element,
A coupling lens portion for optically coupling the optical fiber and the light emitting element, a sleeve portion for holding an end of the optical fiber on one side of the coupling lens so as to be able to be inserted and withdrawn on the optical axis of the coupling lens, and the optical element A connection module obtained by integrally molding a holder unit that holds the substrate so that the microlens of the light emitting element is positioned on the optical axis on the other side of the coupling lens;
Optical communication module provided with. The optical communication module according to claim 1, wherein the microlens is formed by a droplet discharge method. The optical communication module according to any one of claims 1 to 4, wherein the optical element or the light emitting element has a concave portion having a light emitting surface or a light receiving surface at a bottom portion, and the microlens is formed in the concave portion. . The optical communication module according to claim 1, wherein the optical element or the light emitting element has a convex portion on a light emitting surface or a light receiving surface, and the microlens is formed on the convex portion. The optical communication module according to claim 1, wherein the optical element is a light receiving element, and a preamplifier circuit for amplifying an output of the light receiving element is further provided on the optical element substrate. The optical communication module according to any one of claims 1 to 7, wherein at least one of the optical element, the light emitting element, and the light receiving element is covered with a gas-permeable or moisture-permeable resin. 9. The optical communication module according to claim 1, wherein the electric wiring formed on the optical element substrate and the external circuit are connected by a flexible wiring substrate having a microstrip line. The optical communication module according to claim 1, wherein electric wiring of the optical element substrate is formed by a microstrip line. The optical communication module according to any one of claims 1 to 10, wherein at least one of the optical element, the light emitting element, and the light receiving element is housed in a recess formed in the optical element substrate, and the inside of the recess is grounded. . At least one of the optical element, the light emitting element, and the light receiving element is housed in a concave portion formed in the optical element substrate, and the concave portion is embedded with a gas-permeable or moisture-resistant resin. 12. The optical communication module according to any one of 11. The optical element substrate is formed of a stacked body of first and second substrates having a step formed on the outer periphery and the concave portion formed on an upper portion, and is attached to the holder using the step. Item 13. The optical communication module according to any one of Items 1 to 12.

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