JPH0587973U - Optical semiconductor device module - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain an optical semiconductor element capable of reducing an error in front light output due to rear surface light reflected inside the optical semiconductor element. [Structure] The black plated metal inner cap 106 has a cylindrical shape in which one outer diameter is smaller than the inner diameter of the cap 4, a hole having a diameter of 0.7 mm is formed in the end surface, and the other outer diameter is From the inner diameter of the cap 4 to 1 μm to 10
It has a cylindrical shape that is larger by μm. Inner cap 10
One side of 6 is press-fitted inside the cap 4 and is fixed inside the cap 4. [Effect] The rear surface light emitted from the optical semiconductor element chip can be repeatedly reflected inside the optical semiconductor element and emitted from the window glass of the cap can be reduced. Therefore, the measurement accuracy of the front light output can be improved, the coupling efficiency with the optical fiber can be evaluated without error, and the error in the calculation of the reliability of the optical semiconductor element can be reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an optical semiconductor module which is used in a communication device using an optical fiber as a transmission line and which is formed by sealing an optical semiconductor element chip such as a semiconductor laser or a light emitting diode with an optical fiber, which is sealed in an airtight package. is there.

[0002]

[Prior Art]

 FIG. 5 is a perspective view showing an optical semiconductor device incorporated in a conventional optical semiconductor device shown in “Semiconductor Laser” (Baifukan) by Ryoichi Ito and Michiharu Nakamura, for example. Opto-semiconductor element chip, such as 2 is a photodiode chip, 3 is a stem, 4 is a cap, 5 is a window glass made of glass, 6 is a low melting point glass for fixing the window glass 5 to the cap 4. , 7a, 7b, 7c, 7d are electrode terminals, 8 is a terminal fixing low melting glass for fixing the electrode terminals 7a, 7b, 7c to the stem 3, 9a is one electrode and electrode of the optical semiconductor element chip 1 Gold wires 9b and 9c for connecting the terminal 7a are gold wires for connecting the two electrodes of the photodiode chip 2 and the electrode terminals 7b and 7c. The other electrode of the optical semiconductor element chip 1 is connected to the electrode terminal 7d via the stem. In addition, in the figure, the stem 3 and the cap 4 are shown with a part thereof omitted. The electrode terminal 7d is fixed to the stem 3 by welding. The optical semiconductor element chip 1 and the photodiode chip 2 are fixed to the stem 3 with solder. The optical semiconductor element chip 1 and the photodiode chip 2 are hermetically sealed with a window glass 5, a cap 4, a stem 3, electrode terminals 7a, 7b, 7c, a low melting point glass 6 for fixing the window glass, and a melting point glass 8 for fixing the terminal. Has been done. One output light of the optical semiconductor chip 1 is incident on the photodiode chip 2, and the other output light of the optical semiconductor chip 1 is emitted from the cap 4 to the outside of the optical semiconductor element. When the light emitted from the semiconductor device chip to the cap 4 side is the front light and the light emitted to the photodiode 2 side is the rear light, the ratio of the optical output of the front light to the rear light is 1 in the case of a normal semiconductor laser. It is about 1 to 3 to 1. The front light is light that is condensed by a lens or the like and is coupled to the optical fiber. A part of the rear surface light enters the photodiode 2 and is converted into an electric current. Hereinafter, this current is referred to as photocurrent. This photocurrent is usually used to estimate the front light output.

By the way, the emitted light from the optical semiconductor element chip 1 is spread light having a field angle of about 20 to 45 degrees in full width at half maximum, and the optical semiconductor element chip 1 and the photo diode 2 are structurally closely attached. The total amount of the rear surface light emitted from the optical semiconductor element chip 1 does not enter the light receiving surface of the photodiode due to the fact that the size of the light receiving surface of the photodiode 2 is restricted in terms of electrical characteristics and the like. Therefore, only 20% to 50% of the light output of the rear surface light is incident on the light receiving surface of the photodiode 2. Therefore, 80% to 50% of the light output of the rear surface light is incident on the portion other than the light receiving portion of the photodiode 2, the stem 3, etc., and is repeatedly reflected by these portions and the inner surface of the cap 4, etc. A part of the light reflected inside the optical semiconductor element enters the photodiode 2, and most of the other light is emitted from the window glass 5 of the cap 4. The rear surface light reflected inside the optical semiconductor element cannot be condensed by the lens and therefore cannot be coupled to the optical fiber.

In general, in an optical semiconductor element such as a semiconductor laser, the optical semiconductor element is driven with reference to the photocurrent of the photodiode at the time of outputting front light of a certain rating. For this reason, the optical output of the entire surface and the photocurrent of the photodiode are measured in the inspection of the optical semiconductor element, but it is not possible to correctly measure only the optical output of the front surface due to the back surface light reflected inside the optical semiconductor element. .. Therefore, it is not possible to correctly evaluate the coupling efficiency with the optical fiber, which is the ratio of the optical output in the front surface to the optical output in the optical fiber. The measurement error of the front light output due to the back surface light reflected inside the optical semiconductor element is different for each optical semiconductor element chip because the spread angle of the light emitted from the optical semiconductor element chip is different for each optical semiconductor element chip. Wrong . Also, the reliability of the optical semiconductor element is calculated based on the test in which only the front light output of the optical semiconductor element chip alone is measured, and the measurement error of the front light output is the error in the calculation of the reliability of the optical semiconductor element. It becomes a factor.

FIG. 7 shows a conventional optical semiconductor element module disclosed in, for example, Japanese Patent Publication No. 60-136387, in which 20 is a lens, 21 is a lens holder, 22 is an optical fiber, 23 is a ferrule, and 24 is a ferrule holder. Is. The lens 20 is fixed to the lens holder 21 with an adhesive, and the optical fiber 22 is fixed to the ferrule 23 with an adhesive. The positions of the lens 20 and the ferrule 23 are adjusted so that the front light of the optical semiconductor element chip 1 is condensed by the lens 20 and enters the optical fiber 22. The cap 4 and the lens holder 21, and the lens holder 21 and the ferrule holder 24 are fixed by laser welding. The ferrule 23 and the ferrule holder 24 are fixed by solder or the like.

Most of the front light of the optical semiconductor element chip 1 collected by the lens 20 is incident on the optical fiber 22, part of which is Fresnel reflected by the end face of the optical fiber 22, and the other part of which is reflected by the lens 20. Because of the aberration, the light enters the ferrule 23 and is reflected by the end surface of the ferrule 23. The light reflected by the end face of the optical fiber 22 and the light reflected by the end face of the ferrule 23 re-enter the lens 20, but the end faces of the ferrule 23 and the optical fiber 22 are perpendicular to the optical axis of the lens 20. Since it is obliquely polished to an angle of about 8 degrees, it does not pass through the central portion of the lens 20, and most of it re-enters the optical semiconductor element while being diffusely reflected by the side surface of the lens 20. .. Since these lights are reflected by the side surface of the lens 20, they are not coupled to the optical semiconductor element chip 1. However, a part of the light is repeatedly reflected diffusely by the stem 3 of the optical semiconductor element, the inner surface of the cap 4, etc., and is incident on the photodiode 2. Therefore, when the photocurrent of the photodiode 2 is increased and the optical semiconductor element is driven with the photocurrent of the photodiode 2 at the time of the front light output of a certain rating as a reference, the front light output decreases. Therefore, in addition to the error of the front light output due to the back surface light reflected inside the optical semiconductor element described above, the measurement error of the front light output due to the light reflected at the end face of the optical fiber and the light reflected at the end face of the ferrule causes The coupling efficiency with the optical fiber cannot be evaluated correctly. The reliability of optical semiconductor elements is calculated based on a test in which only the front light output of a single optical semiconductor element chip is measured.The front light output is estimated based on the photocurrent of the photodiode. It causes an error in the calculation of the reliability of the element.

[0007]

[Problems to be solved by the device]

 Since the conventional optical semiconductor device module is configured as described above, it is not possible to correctly measure only the front light output due to the back surface light reflected inside the optical semiconductor device. In addition, a part of the light reflected by the end face of the optical fiber and the light reflected by the end face of the ferrule enters the photodiode and increases the photocurrent of the photodiode. For these reasons, the coupling efficiency with the optical fiber cannot be evaluated correctly, and the reliability of the optical semiconductor element is calculated based on a test in which only the front light output of the semiconductor element chip alone is measured. Since the light output is estimated based on the photocurrent of the photodiode, there were problems such as an error factor in the calculation of the reliability of the semiconductor element.

The present invention has been made to solve the above problems, and can reduce the error in the front light output due to the rear surface light reflected inside the optical semiconductor element, and further, it can be reflected inside the optical semiconductor element. An object of the present invention is to obtain an optical semiconductor element module capable of reducing the error in the front light output due to the rear surface light and the error in the front light output due to the light reflected by the end face of the optical fiber and the light reflected by the end face of the ferrule.

[0009]

[Means for Solving the Problems]

 The optical semiconductor device module according to the present invention is provided with a window glass, a cap and a stem, a reflective film is attached to a portion other than a diameter of 0.6 mm at the center of the window glass, and the window glass is fixed to the cap. The metal part of the fixed cap is black plated.

Another optical semiconductor device module according to the present invention includes a window glass, a cap, a stem, and a metal inner cap. The window glass is fixed to the cap, and the window glass is fixed inside the cap. The inner cap is fixed, and the inner cap is black plated.

Further, another optical semiconductor element module according to the present invention is provided with a window glass, a cap, a stem, and a lens holder made of metal, and a reflective film is provided on a portion of the central portion of the window glass other than 0.6 mm in diameter. The lens is fixed to the lens holder by attaching the window glass to the cap, plating the metal part of the cap to which the window glass is fixed with black plating, making the inner surface of the lens holder black.

Further, another optical semiconductor element module according to the present invention includes a window glass, a cap, a stem, a metal inner cap, and a metal lens holder, and fixes the window glass to the cap and fixes the window glass. The inner cap is fixed to the inside of the cap, the inner cap is black-plated, the inner surface of the lens holder is black, and the lens is fixed to the lens holder.

[0013]

[Action]

 In the optical semiconductor device module according to this invention, the metal part of the cap to which the window glass is fixed is plated with black, so that it is possible to reduce the reflection of the rear surface light emitted from the optical semiconductor device chip inside the optical semiconductor device. Since the reflection film is attached to the central portion of the window glass other than the diameter of 0.6 mm, it is possible to reduce the emission of the rear surface light reflected inside the optical semiconductor element from the window glass fixed to the cap. Therefore, the measurement accuracy of the front light output can be improved, the coupling efficiency with the optical fiber can be evaluated without error, and the error in the calculation of the reliability of the optical semiconductor element can be reduced.

In addition, in another optical semiconductor device module of the present invention, a black plated metal inner cap is fixed inside the cap to which the window glass is fixed, so that the rear surface emitted from the semiconductor device chip is fixed. It is possible to reduce the reflection of light inside the optical semiconductor element, and to reduce the increase in the photocurrent of the photodiode due to the back surface light reflected inside the optical semiconductor element. Therefore, the measurement accuracy of the front light output can be improved, the coupling efficiency with the optical fiber can be evaluated without error, and the error in calculating the reliability of the optical semiconductor element can be reduced.

Further, in another optical semiconductor element module of the present invention, since the metal portion of the cap to which the window glass is fixed is black-plated, the rear surface light emitted from the semiconductor element chip is the optical semiconductor element. It is possible to reduce internal reflection, and since a reflection film is attached to the central part of the window glass other than the diameter of 0.6 mm, the rear surface light reflected inside the optical semiconductor element can be emitted from the window glass fixed to the cap. The emission can be reduced. In addition, since the inner surface of the metal lens holder that fixes the lens is black, the light that is Fresnel-reflected by the end face of the optical fiber and the light that is reflected by the end face of the ferrule can be reduced on the inner surface of the lens holder. It is possible to suppress the incident on the photodiode to increase the photocurrent of the photodiode. For these reasons, the measurement accuracy of the front light output can be improved, the coupling efficiency with the optical fiber can be evaluated without error, and the error in the calculation of the reliability of the optical semiconductor element can be reduced.

Further, in another optical semiconductor element module of the present invention, the inner cap made of black-plated metal is fixed inside the cap fixed with the window glass, so that the rear surface light emitted from the optical semiconductor element chip is Light inside the optical semiconductor element can be reduced, and since the inner surface of the metal lens holder that fixes the lens is black, the light reflected by the end face of the optical fiber and the end face of the ferrule are reflected. Light can be reduced on the inner surface of the lens holder, and it is possible to prevent these lights from entering the photodiode and increasing the photocurrent of the photodiode. Because of these, the measurement accuracy of the front light output can be improved, the coupling efficiency with the optical fiber can be evaluated without error, and the error in the calculation of the reliability of the optical semiconductor element can be reduced.

[0017]

【Example】

 Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 104 is a black cap plated with black on Kovar, and reference numeral 105 is a window glass with a reflection film in which a reflection film of nickel-chromium alloy is vapor-deposited on portions other than the central diameter of 0.6 mm. The window glass 105 with a reflection film is fixed to the black cap 104 with a low melting point glass 6 for fixing the window glass. The black cap 104 is fixed to the stem 3 by Joule heat welding. The optical semiconductor element chip 1 and the photodiode chip 2 include a black cap 104, a window glass 105 with a reflection film, a stem 3, electrode terminals 7a, 7b and 7c, a low melting point glass 6 for fixing the window glass, and a melting point for fixing the terminal. It is hermetically sealed with glass 8. The interval between the optical semiconductor element 1 and the window glass 105 with a reflective film is 0.2 mm or less. Even if the mounting accuracy of the optical semiconductor element chip 1 is 0.05 mm or less and the mounting accuracy of the black cap 105 is 0.15 mm or less, the front light emitted from the optical semiconductor element chip 1 with a full angle of 53 degrees or more is reflected by the window with a reflection film. Can penetrate glass. In the drawings, the same reference numerals as those in the above-mentioned conventional example indicate the same or corresponding portions.

Of the rear surface light emitted from the semiconductor element chip 1, the light is incident on the portion other than the light receiving portion of the photodiode 2, the stem 3, etc., and the light reflected partially is incident on the inner surface of the black cap 104. Since the inner surface of the black cap 104 is black, most of it is absorbed by the inner surface of the black cap 104. Further, since the reflective film is formed on the peripheral portion of the window glass 105 with the reflective film, it is possible to reduce the emission of the light reflected by the inner surface of the black cap 104 from the window glass 105 with the reflective film. Therefore, the measurement accuracy of the front light output can be improved, the coupling efficiency with the optical fiber can be evaluated without error, and the error in the calculation of the reliability of the optical semiconductor element can be reduced.

Example 2. Next, another embodiment of the present invention will be described with reference to the drawings. In FIG. 2, 106 is an inner cap made of brass plated with black. One of the inner caps 106 has a cylindrical shape with an outer diameter smaller than the inner diameter of the cap 4, and has a hole with a diameter of 0.7 mm formed on the end surface. The other of the inner caps 106 has a cylindrical shape whose outer diameter is 1 μm to 10 μm larger than the inner diameter of the cap 4. When the inner cap 106 is inserted into the cap 4, one of the inner caps 106 is press-fitted inside the cap 4 and fixed inside the cap 4. The distance between the optical semiconductor element chip 1 and the inner cap 106 is 0.1 mm or less, the mounting accuracy of the optical semiconductor element chip 1 is 0.05 mm or less, the mounting accuracy of the cap 105 is 0.15 mm or less, and the mounting accuracy of the inner cap 106 is 0. Even if the thickness is less than 0.1 mm, front light emitted from the optical semiconductor element chip 1 and having a full angle of 53 degrees or more can pass through the window glass 5. In the figure, the same reference numerals as those in the above-mentioned conventional example indicate the same or corresponding portions.

The rear surface light emitted from the optical semiconductor element chip 1 is incident on a portion other than the light receiving portion of the photodiode 2, the stem 3, and the like, and the partially reflected light is incident on the inner surface of the inner cap 106. Since the inner surface of the cap 106 is black, it is absorbed by the inner surface of the inner cap 106. Further, since the hole is formed in the upper portion of the inner cap 106, it is possible to reduce the emission of the light reflected by the inner surface of the inner cap 106 from the window glass 5. Therefore, the measurement accuracy of the front light output can be improved, the coupling efficiency with the optical fiber can be evaluated without error, and the error in the calculation of the reliability of the optical semiconductor element can be reduced.

Example 3. Next, another embodiment of the present invention will be described with reference to the drawings. In FIG. 3, reference numeral 121 denotes a stainless black lens holder which is entirely plated with black. The lens 20 is fixed to the lens holder 121 with a transparent adhesive. In the drawings, the same reference numerals in the above-described embodiment and the conventional example indicate the same or corresponding portions.

Similar to the above-described first embodiment, in the rear surface light emitted from the optical semiconductor element chip 1, the light reflected by the portion other than the light receiving portion of the photodiode 2, the stem 3, etc. is reflected by the inner surface of the black cap 104. Since it is black, most of it is absorbed. Further, since the reflective film is formed around the reflective glass window glass 105, the light reflected by the inner surface of the black cap 104 can be reduced from being emitted from the reflective film window glass 105. Therefore, the measurement accuracy of the front light output can be improved, the coupling efficiency with the optical fiber can be evaluated without error, and the error in the calculation of the reliability of the optical semiconductor element can be reduced.

Of the front light emitted from the optical semiconductor element chip 1, the light that has been Fresnel-reflected by the end face of the optical fiber 22 and the light that has been reflected by the end face of the ferrule 23 re-enters the lens 20. Since the end face of the fiber 22 is obliquely polished so as to form an angle of about 8 degrees with respect to the surface perpendicular to the optical axis of the lens 20, most of it does not pass through the center of the lens and is incident on the side surface of the lens 20. To do. The light incident on the side surface of the lens 20 passes through the adhesive agent that fixes the lens 20 to the black lens holder and enters the inner surface of the black color lens holder 121. This light is absorbed by the inner surface of the black lens holder 121 because the inner surface of the black lens holder 121 is black. For this reason, it is possible to suppress an increase in the photocurrent of the photodiode caused by the light reflected by the end surface of the optical fiber 22 and the light reflected by the end surface of the ferrule 23 entering the photodiode. Therefore, the measurement accuracy of the front light output can be improved, the coupling efficiency with the optical fiber can be evaluated without error, and the error in the calculation of the reliability of the optical semiconductor element can be reduced.

Example 4. Next, another embodiment of the present invention will be described with reference to the drawings. In FIG. 4, 106 is an inner cap made of brass plated with black, and 121 is a stainless steel lens holder entirely plated with black. The lens 20 is fixed to the lens holder 121 with a transparent adhesive. In the drawings, the same reference numerals as those in the above-described embodiment and the conventional example indicate the same or corresponding portions.

Similar to the above-described second embodiment, the rear surface light emitted from the optical semiconductor element chip 1 and reflected by the portion other than the light receiving portion of the photodiode 2 or the stem 3 has a black inner surface of the inner cap 106. As a result, it is absorbed by the inner surface of the inner cap 106. Further, since the hole is formed in one side of the inner cap 106, it is possible to reduce the amount of light reflected by the inner surface of the inner cap 106 being emitted from the window glass of the cap. Therefore, the measurement accuracy of the front light output can be improved, the coupling efficiency with the optical fiber can be evaluated without error, and the error in the calculation of the reliability of the optical semiconductor element can be reduced.

Further, as in the case of the above-described third embodiment, the light that is Fresnel-reflected by the end face of the optical fiber 22 and the light that is reflected by the end face of the ferrule 23 by the front face light emitted from the optical semiconductor element chip 1 of the lens holder 121 Since the inner surface is black, it is absorbed by the inner surface of the lens holder 121. Therefore, these lights are reduced and can be suppressed from entering the photodiode 2 and increasing the photocurrent of the photodiode 2. Therefore, the measurement accuracy of the front light output can be improved, the coupling efficiency with the optical fiber can be evaluated without error, and the error in the calculation of the reliability of the optical semiconductor element can be reduced.

[0027]

[Effect of the device]

 As described above, according to the present invention, the rear surface light emitted from the optical semiconductor element chip is repeatedly reflected inside the optical semiconductor element, and the emission from the window glass of the cap can be reduced. Therefore, the measurement accuracy of the front light output can be improved, the coupling efficiency with the optical fiber can be evaluated without error, and the error in the calculation of the reliability of the optical semiconductor element can be reduced.

Further, the light reflected on the end face of the optical fiber and the light reflected on the end face of the ferrule can be reduced on the inner face of the metal holder, and these lights are incident on the photodiode to increase the photocurrent of the photodiode. Can be suppressed. Because of these, it is possible to improve the measurement accuracy of the front light output, evaluate the coupling efficiency with the optical fiber without error, and reduce the error in the calculation of the reliability of the optical semiconductor element.

[Brief description of drawings]

FIG. 1 is a sectional view showing an optical semiconductor device module according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an optical semiconductor device module according to another embodiment of the present invention.

FIG. 3 is a sectional view showing an optical semiconductor device module according to another embodiment of the present invention.

FIG. 4 is a sectional view showing an optical semiconductor device module according to another embodiment of the present invention.

FIG. 5 is a perspective view showing a conventional optical semiconductor element.

FIG. 6 is a cross-sectional view showing a conventional optical semiconductor device module.

[Explanation of symbols]

 1 Optical Semiconductor Element Chip 3 Stem 4 Cap 5 Window Glass 104 Black Cap 105 Window Glass with Reflective Film 106 Inner Cap 121 Black Lens Holder

Claims (4)

[Scope of utility model registration request] 1. An optical semiconductor element module in which an optical semiconductor element chip is sealed in an airtight package, and the optical semiconductor element chip and an optical fiber are optically coupled or can be coupled via a lens. The optical semiconductor element chip is hermetically sealed with at least the window glass, the cap and the stem, and a reflection film is attached to the central portion of the window glass other than the diameter of 0.6 mm to cap the window glass. An optical semiconductor element module characterized in that a metal part of a cap fixed to a window glass is fixed to the metal plate and black plating is applied thereto. 2. An optical semiconductor element module in which an optical semiconductor element chip is sealed in an airtight package, and the optical semiconductor element chip and an optical fiber are optically coupled or can be coupled via a lens, in a window glass. And a cap, a stem and an inner cap made of metal, at least an optical semiconductor element chip is hermetically sealed with the window glass, the cap and the stem, the window glass is fixed to the cap, and the inside of the cap fixing the window glass is fixed. An optical semiconductor element module, wherein an inner cap is fixed, and the inner cap is plated with black. 3. An optical semiconductor element module in which an optical semiconductor element chip is sealed in an airtight package, and the optical semiconductor element chip and an optical fiber are optically coupled or can be coupled via a lens. And a cap, a stem and a metal lens holder are provided, the optical semiconductor element chip is hermetically sealed with at least the window glass, the cap and the stem, and a reflection film is attached to the central portion of the window glass other than the diameter 0.6 mm An optical semiconductor element module characterized in that the window glass is fixed to a cap, the metal portion of the cap to which the window glass is fixed is plated with black, the inner surface of the lens holder is made black, and the lens is fixed to the lens holder. .. 4. An optical semiconductor element module in which an optical semiconductor element chip is sealed in an airtight package, and the optical semiconductor element chip and an optical fiber are optically coupled or can be coupled via a lens. And a cap, a stem, a metal inner cap, and a metal lens holder are provided, and the optical semiconductor element chip is hermetically sealed with at least the window glass, the cap, and the stem, and the window glass is fixed to the cap. An optical semiconductor element module, wherein an inner cap is fixed inside the fixed cap, the inner cap is black-plated, the inner surface of the lens holder is black, and the lens is fixed to the lens holder.