JPH05173045A - Optical semiconductor module - Google Patents

Abstract

PURPOSE:To provide an optical semiconductor module having high heat resistance and high reliability. CONSTITUTION:The optical semiconductor module is constituted of an optical semiconductor element such as a laser diode 30, a condensing lens 33 and optical elements such as prisms 34 to 36 made of optical glass and respective parts are mounted and arranged on the surface of a substrate 37 made of silicone or the like. The optical semiconductor element is fixed on a metallic thin film formed on e substrate 37 and provided with a positioning/fixing function and an electrode function and the lens 33 and the optical elements are also arranged and fixed on grooves 38, 39 formed on the substrate 37. The optical elements arranged on the prism groove 39 are fixed on the substrate 37 by irradiating a low melting point glass pellet arranged between the elements and the substrate 37 with laser beams and melting the pellet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical semiconductor module for bidirectional optical communication, and more particularly to a structure for fixing optical elements such as a condenser lens and a prism constituting the optical semiconductor module to a substrate.

[0002]

2. Description of the Related Art Generally, an LD module or a light receiving module is a basic optical device that constitutes an optical communication system.
These are composed of a laser diode (LD) that is a light emitting element or a photodiode (PD) that is a light receiving element, an optical fiber, a lens that optically couples these, and a housing that fixes and mounts these.

Up to now, the optical communication system has been attempted to increase the speed and expand the transmission distance mainly in the trunk line system. In the future, the optical communication system will be applied not only to the trunk line system but also to the local area network (LAN) in the building and the subscriber system for general households by taking advantage of its characteristic that it can transmit signals over a wide band. Has started.

In such an optical communication system intended for a wide range of users, not only the functions and performances of a high-capacity trunk line system, but also the economical efficiency of the system is one of the most important conditions for introduction, and the system is constructed. There is a strong demand for lower device prices. In particular, among the devices for the optical communication system, a large proportion of the cost is the optical device, that is, the LD module or APD (avalanche photo
It is an optical semiconductor module such as a diode module, and it is considered that lowering the price of these optical devices is essential for introducing and putting into practical use the optical subscriber system. Also,
In the optical subscriber system, in addition to the above-mentioned cost reduction of the optical device, since the device is installed in each subscriber, downsizing of the device is also an important issue.

On the other hand, as a function required for this optical subscriber system, communication and CATV (cable television) are used in order to utilize the wide band property of optical communication to differentiate it from the conventional coaxial cable communication and increase the added value. ) Etc. are being considered for integration with broadcasting functions. Due to the strict price reduction demands of the subscriber system mentioned above, bidirectional transmission with the same wavelength by using an optical coupler in a single optical fiber or wavelength division multiplexing by using different wavelengths for upstream and downstream The method of transmission is considered to be promising.

For example, as means for enabling bidirectional optical transmission having the above-mentioned wavelength multiplexing function and branching function, a 1.3 μm LDD module 1, a 1.3 μm light receiving module 2 and 1 as shown in FIG. Light receiving module 3 for 0.55 μm
There is proposed a structure in which the optical coupler 4 and the optical multiplexer / demultiplexer 5 are individually combined via the optical connector 6. According to this structure, the characteristics of individual devices can be confirmed in advance for configuration, but on the other hand, there are problems that connector loss occurs when the devices are coupled to each other and the overall configuration becomes large. Therefore, it is considered to be difficult to apply it to an optical subscriber system, which is particularly required to downsize the entire device.

In view of this, as shown in FIGS. 4 and 5, an optical semiconductor element (laser diode 7, photodiode 8, PIN photodiode 9) and a condenser lens 10 are provided to improve miniaturization and mass productivity. Prism (triangular prism 11, parallelogram prism 12, trapezoidal prism 1
A structure having an optical element such as 3) arranged on the substrate 14 has already been proposed. That is, in this structure,
Positioning the optical semiconductor element formed on the substrate 14,
It is fixed on the metal thin film 20 that has both fixing and electrodes. Further, the condenser lens 10 and the optical element are also arranged and fixed in the grooves 15 and 16 for positioning and fixing which are formed on the substrate 14.

With this structure, the optical semiconductor element, the condenser lens 10 and the optical element can be accurately positioned and fixed to the substrate 14. Further, the light emitted or made incident from a plurality of optical semiconductor elements is branched and combined by an optical element which vapor-deposits the wavelength separation filter 17 and the half mirror 18 and has a total reflection surface 19, and enters the optical fiber terminal 21. In FIG. 5, 22 is a rod lens and 23 is an optical fiber. By adopting a structure in which all the components are placed on one substrate 14 in this way, it is possible to achieve miniaturization.

Further, for example, a silicon substrate is used as the substrate 14, and a metal thin film 20 for fixing an optical semiconductor element is manufactured by vapor deposition and photolithography. Further, grooves 15 and 16 for fixing the condenser lens 10 and the optical element.
Can be produced using a technique such as anisotropic chemical etching of silicon. If such a manufacturing method is adopted, a large amount of products can be manufactured by batch processing, so that mass productivity is also improved.

[0010]

However, when manufacturing the above-described conventional optical semiconductor module, the optical semiconductor element, the condenser lens 10 and the optical element are sequentially adjusted in position and fixed to the substrate 14. Is becoming In the fixing method currently implemented, a method of heating the fixing portion like solder is adopted, but in this method, heat is applied not only to the fixing portion but to the entire optical semiconductor module.

Therefore, when fixing each component, in order to prevent a phenomenon in which other components that have already been fixed are displaced due to an increase in the temperature of the fixing portion, it is necessary to fix the components in order of higher fixing temperature. .. For example, when a solder is used to fix the optical semiconductor element, a low melting point glass is used to fix the condensing lens 10, and an adhesive is used to fix the optical element, the low melting point glass>solder> adhesive in descending order of the fixing temperature. Since it becomes a drug, the fixation is
This is performed in the order of the condenser lens, the optical semiconductor element, and the optical element. In order to fix them in this manner, it is necessary to use different fixing materials for each part.

Here, the optical element used in the present optical semiconductor module has a wavelength separation filter 17 and a half mirror 18 deposited thereon, and the heat resistance of the deposited portion is only about the curing temperature of the thermosetting adhesive. Absent. Therefore, the heat resistance of the optical element is limited. That is, only an adhesive can be used to fix the optical element. However, as compared with other fixing methods, the adhesive has a lower fixing temperature and thus is inferior in heat resistance, resulting in lower reliability of the fixing portion of the optical element. As a result, the heat-resistant temperature of the entire optical semiconductor module becomes the heat-resistant temperature of the adhesive, resulting in low reliability.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide an optical semiconductor module having excellent heat resistance and high reliability.

[0014]

The invention according to claim 1 is
An optical element having a filter having a function of branching and coupling light, at least two optical semiconductor elements, and a lens arranged in front of each optical semiconductor element, each optical semiconductor element being an optical element and a lens. In an optical semiconductor module optically coupled with an optical fiber via, an optical semiconductor element, a lens and an optical element are arranged and fixed on the same substrate, and a low melting point glass pellet is provided between the substrate and the optical element. The low melting glass pellets are arranged and heated and melted to fix the substrate and the optical element.

The invention according to claim 2 is characterized in that a counterbore for disposing the low melting point glass pellets is provided on the substrate.

According to a third aspect of the present invention, the spot facing is formed by etching the surface of the substrate.

[0017]

According to the present invention, since the laser beam is used for heating, local heating occurs, and the optical element can be fixed to the substrate without damaging the vapor deposition film formed on the end face of the prism. As a result, since it is possible to fix the low-melting-point glass only to the area where the heat resistance is poor, which can be fixed only by the conventional adhesive, it is possible to manufacture a highly reliable optical semiconductor module having excellent heat resistance.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view showing an embodiment of an optical semiconductor module according to the present invention, and FIG. 2 is a partially enlarged perspective view of the optical semiconductor module. Optical semiconductor element (laser diode 30, photodiode 31, PIN photodiode 32), condenser lens 33 and prism (triangular prism 34, parallelogram prism 35, trapezoidal prism 36) arranged on the front surface of the optical semiconductor element And other optical elements are mounted and arranged on a substrate 37 made of silicon or the like. The optical semiconductor element is fixed on a metal thin film (not shown) formed on the substrate 37 for positioning, fixing, and electrodes, and the condenser lens 33 and the optical element are also positioned and fixed on the substrate 37. It has a structure in which it is arranged and fixed in the grooves 38, 39 for carrying out. Optical semiconductor element and condensing lens 3
3 and the optical element are accurately positioned by the positioning and fixing grooves 38 and 39, and can be fixed to the substrate 37 as they are. As a fixing method, the optical semiconductor element uses solder, and the condenser lens 33 uses low melting point glass.

After positioning and fixing the semiconductor element and the condenser lens 33, the wavelength separation filter 40 and the half mirror 41 are arranged.
Trapezoidal prism 36 and parallelogram prism 3
5. Fix the optical element with the triangular prism 34 stuck together. At this time, the optical element is fitted in the prism groove 39 for positioning and fixing the optical element, and the low melting point glass pellet 43 is inserted in the glass pellet arrangement grooves 42 provided at several places continuously with the prism groove 39 as shown in FIG. It is arranged so as to contact both the optical element and the substrate 37. And
The low melting glass pellet 43 is irradiated with a high output laser beam 44 and melted to fix the optical element to the substrate 37. Here, a CO ₂ laser which is generally used as a high power laser is used. After fixing the optical element, the entire substrate 37 is fixed to the package as in the conventional optical semiconductor, and the optical fiber terminal is adjusted and fixed. The trapezoidal prism 36 is provided with a total reflection surface 45.

Since the step of providing the glass pellet placement groove 42 on the substrate 37 can be performed simultaneously with the production of other grooves, there is no difference from the conventional manufacturing method. Further, no thermal influence was observed on the wavelength separation filter 40 deposited on the optical element.

A special step required for manufacturing the optical semiconductor module of the present invention is a step of melting the low melting point glass pellet 43 by using a laser beam 44, but laser processing is a very simple method. is there. For this reason,
The reliability is higher and the work can be performed more easily than the conventional process of curing a resin such as an adhesive. Further, as the irradiation beam for melting the low melting point glass pellets 43, any one other than a CO ₂ laser can be used as long as it is easily absorbed by glass and can give a sufficient amount of heat to the low melting point glass pellets 43. The kind of thing is applicable.

[0022]

As described above, according to the optical semiconductor module of the present invention, the low melting point glass pellets are arranged between the substrate and the optical element, and the low melting point glass pellets are irradiated with the laser beam and melted. With this structure, since the substrate and the optical element are fixed to each other, there is an effect that the fixing can be performed with high reliability without damaging the wavelength separation filter or the half mirror deposited on the optical element. Further, since no adhesive is used, there is an effect that it is possible to shorten the time conventionally required to cure the adhesive.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of an optical semiconductor module according to the present invention.

FIG. 2 is a partially enlarged perspective view of the optical semiconductor module.

FIG. 3 is a schematic configuration diagram of a conventional optical transceiver module using individual optical devices.

FIG. 4 is an exploded perspective view showing an example of a conventional optical semiconductor module.

FIG. 5 is an assembled perspective view showing an example of a conventional optical semiconductor module.

[Explanation of symbols]

 30 laser diode 31 photodiode 32 PIN photodiode 33 condensing lens 34 triangular prism 35 parallelogram prism 36 trapezoidal prism 37 substrate 38, 39 groove 40 wavelength separation filter 42 glass pellet arrangement groove 43 low melting point glass pellet 44 laser beam

Claims (3)

[Claims] 1. An optical element having a filter having a function of branching / coupling light, at least two optical semiconductor elements, and a lens arranged on the front surface of each optical semiconductor element. In an optical semiconductor module, which is optically coupled to an optical fiber via an optical element and a lens, wherein the optical semiconductor element, the lens, and the optical element are arranged and fixed on the same substrate, and the substrate and the optical element An optical semiconductor module, characterized in that a low-melting glass pellet is arranged between them, and the low-melting glass pellet is irradiated with a laser beam for heating and melting to fix the substrate and the optical element. 2. The optical semiconductor module according to claim 1, wherein the substrate is provided with a spot facing for arranging the low melting point glass pellet. 3. The optical semiconductor module according to claim 2, wherein the spot facing is formed by etching the surface of the substrate.