JP2000193852A - Optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical module which is capable of achieving optical connection with high efficiency, and reducing the number of parts, and easy in wiring using wire bonding, etc. SOLUTION: An upper main surface of a lower substrate 1 is provided with an inverted trapezoidal groove 3 for a reflecting surface 4, the reflecting surface 4 to reflect the laser beam approximately perpendicularly upward, a groove 8 formed not to cut off an optical path, an electrode 9 to supply power to an LD 15 which is a light-emitting device, a V-shaped groove (a) for fixing an optical fiber 17, a groove (c) for installing a spherical lens 18, and a groove (b) of recessed section for installing an optical filter 16, and a lower main surface of an upper substrate 2 is provided with an electrode to supply the output of a PD 20, a Fresnel zone lens 21 to converge the reflected light from the reflecting surface 4, a V-shaped groove for installing the optical fiber 17, a groove for installing the spherical lens 18, and a groove of recessed section for installing the optical filter 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a bidirectional optical module having a light source such as a semiconductor laser, an optical fiber, a condenser lens, and a light receiving element such as a photodiode mounted on a substrate.

[0002]

2. Description of the Related Art Conventionally, there has been proposed an optical module in which optical components such as an optical fiber and a light receiving / emitting element are disposed on a substrate and optically coupled to each other. Optical connection with low loss is very important. Therefore, as a technique for realizing high-precision optical connection, a method of performing anisotropic etching or the like on a silicon substrate to form a V-groove or a conductor pattern with high accuracy has been studied.

In such anisotropic etching, a (100) plane silicon substrate is generally etched using an aqueous solution of potassium hydroxide or the like, and the etching rate is low (111).
This is done by exposing the face. Since the V-groove obtained by anisotropically etching the (100) plane silicon substrate utilizes the crystal orientation, the angle between the silicon substrate surface and the V-groove is necessarily 54.7 °.

As a conventional example of mounting a semiconductor laser element on a silicon substrate subjected to anisotropic etching, the present invention relates to a semiconductor laser device used for optical information processing, optical measurement, optical communication, and the like. 1 to 1
The (511) plane silicon substrate having an off-angle of 11 ° and the slopes on both sides formed on the silicon substrate are (1).
11) A groove having a V-shaped cross section on the surface and an upper end ridge line of a slope facing a reflection mirror surface which is inclined at an angle of about 45 ° with respect to the surface of the silicon substrate among slopes forming the groove. By providing a semiconductor laser chip on a silicon substrate so as to be substantially parallel to each other, a laser beam can be extracted in a substantially vertical direction, and an alignment in an emission direction is easily performed (Japanese Patent Laid-Open No. Hei 5 (1994)). -315
699). FIG. 12 shows a partial sectional view of the semiconductor laser device. In the figure, 31 is a silicon substrate, 32 is a reflection mirror surface, 33 is a semiconductor laser device, 3
4 is an optical path.

[0005]

However, as shown in FIG. 12, the above-described conventional semiconductor laser device has an optical axis height of a laser beam emitted from a semiconductor laser element (Laser diode, hereinafter abbreviated as LD) 33. And the upper end of the reflection mirror surface 32 is substantially at the same height, so that the amount of laser light extracted upward is reduced by half. Therefore, LD33
In order to increase the amount of reflected light by lowering the surface on which the light is placed to be lower than the upper end of the reflection mirror surface 32, in the case of a type in which an optical fiber and a condenser lens are mounted on the substrate 31 as in the present invention, the LD 33 is mounted. Mounting surface, forming surface of V-groove for mounting optical fiber,
It is necessary that the surface on which the V-groove for mounting a condenser lens such as a spherical lens is formed to be lower than the upper end of the reflection mirror surface 32 by half or more of the laser beam diameter in advance. For example, when a spherical lens having a diameter of 600 μm is used as a condensing lens, the maximum is 300 μm,
In the case of a spherical lens having a diameter of 800 μm, the maximum value is reduced by 400 μm.

As a method for lowering the mounting surface of the LD 33, the surface for forming the optical fiber mounting V-groove, and the surface for forming the condensing lens mounting V-groove, there are a grinding method such as a dicing method and an etching method. In the case of the dicing method, electrodes and V-grooves cannot be formed because the surface after dicing is rough.

Accordingly, the present invention has been completed in view of the above circumstances, and an object of the present invention is to make it possible to take out light almost vertically upward without reducing the amount of light, and as a result, to carry out an extremely efficient optical connection. A separate lid is not required because the upper substrate is also used as a lid, reducing the number of components. Is to do.

[0008]

An optical module according to the present invention has a lower substrate and a translucent upper substrate, and a light emitting element mounting portion and a light emitting element facing the light emitting element are provided on the upper main surface of the lower substrate. V groove a for fixing an optical fiber, a groove b for setting an optical filter formed on the optical axis between the light emitting element and the V groove a, and light reflected by the optical filter. And a reflecting surface for reflecting the light substantially vertically upward, and the light emitting element mounting portion is located closer to the reflecting surface than the upper end of the reflecting surface, and the light reflected by the reflecting surface is collected on the lower main surface of the upper substrate. A condenser lens and a light receiving element are provided, and a lower main surface of the upper substrate and an upper main surface of the lower substrate are overlapped.

According to the present invention, the light from the light emitting element can be almost completely extracted vertically upward by the above configuration, and as a result, an extremely efficient optical connection is realized. In addition, since the lid is not required, the number of components is reduced, and since the light emitting / receiving element is mounted on the upper portion of the substrate, wiring by wire bonding or the like is facilitated and workability is improved. Furthermore, a Fresnel zone lens for condensing the reflected light on the upper substrate can be formed by a film forming technique, and a condensing lens for condensing the reflected light is not required. Shortening.

In the present invention, preferably, the condenser lens provided on the upper substrate is a Fresnel zone lens or a spherical lens.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A bidirectional optical module M1 of the present invention is shown in FIGS. FIG. 1 is a plan view of the optical module M1, FIG. 2A is a cross-sectional view taken along line AA ′ of FIG. 1 (the optical axis of the laser beam emitted from the LD 15), and FIG.
FIG. 2B is a cross-sectional view taken along the line BB ′ of FIG. 1, and FIG.
FIG. 3 is a sectional view taken along line CC ′ of FIG.
4A is a sectional view taken along line AA 'in FIG. 3, FIG. 4B is a sectional view taken along line BB' in FIG. 3, and FIG. 5A is a cross-sectional view taken along the line AA 'in FIG. 5, and FIG. 6B is a cross-sectional view taken along the line AA' in FIG. 6 (c) is a cross-sectional view taken along the line CC 'of FIG.

In these figures, 1 is a lower substrate, 2 is a translucent upper substrate, and an upper main surface of the lower substrate 1 has
An inverted trapezoidal groove 3 for the reflection surface 4, a reflection surface 4 for reflecting a laser beam substantially vertically upward, a groove 8 formed so as not to block an optical path, an electrode 9 for supplying power to an LD 15 as a light emitting element, A V-groove a for fixing (pressing) the optical fiber, a groove c for setting the spherical lens, and a groove b having a concave cross section for setting the optical filter 16 are formed. Also, the upper substrate 2 has
An electrode 14 for extracting an output of a photodiode (hereinafter abbreviated as PD) of a light receiving element, a Fresnel zone lens 21 as a condenser lens for condensing light reflected from the reflection surface 4, a V-groove a1 for installing an optical fiber 17, A groove c1 for setting the spherical lens 18 and a groove b1 having a concave cross section for setting the optical filter 16 are provided. The light emitting element mounting portion in the present invention is a surface portion on which the LD 15 is mounted and the electrode 9 is formed.

The optical module M1 of the present invention is bidirectional and functions as follows. For example, a light wavelength (hereinafter, referred to as a wavelength) emitted from the LD 15 is 1.31 μm.
Is transmitted through an optical filter 16 which is a wavelength selection filter, and is incident on an optical fiber 17. The optical fiber 17 is connected to an external optical communication device, information processing device, measuring device, or the like.
The return light comes back. The light having a wavelength of 1.55 μm is reflected by the optical filter 16, reflected by the reflection surface 4, detected by the PD 20, and output as information in optical communication and a measured value in optical measurement.

In the above example, the optical filter 16 is a wavelength selection filter, but may be a polarization beam splitter. In that case, for example, the linearly polarized light emitted from the LD 15 passes through the polarization beam splitter and passes through the optical fiber 17.
, And return light of random polarization from the optical fiber 17 may be reflected by the polarization beam splitter.

The optical module M1 of the present invention has a lower substrate 1 and a translucent upper substrate 2, and as shown in FIG. 1, the area of the upper substrate 2 is made smaller than that of the lower substrate 1. hand,
It is preferable that at least the electrode 9 and the LD 15 of the lower substrate 1 be exposed to the outside. With this configuration, connection between the LD 15 and the electrode 9 and an external drive circuit can be easily performed by wire bonding or the like. The lower substrate 1 is preferably made of silicon which can be easily processed by the anisotropic etching method.
Is a light-transmitting material, and is preferably silicon, GaAs, SiO ₂ glass, quartz, rutile or the like having a light-transmitting property with respect to infrared light, and among them, silicon which can be easily processed by an anisotropic etching method is preferable.

Further, as shown in FIG. 4C, the lower substrate 1 has L in a direction perpendicular to the main surface of the lower substrate 1.
The D15 mounting portion is located at a position closer to the reflection surface 4 than the upper end 4t of the reflection surface 4, and as a result, the laser beam is almost vertically reflected by the reflection surface 4 (FIG. 2C). The height difference between the upper end 4t and the light emitting portion of the LD 15 in the direction perpendicular to the main surface of the lower substrate 1 is preferably 50 to 250 μm, and 50 μm.
If it is less than the above, the amount of light that does not hit the reflection surface increases, and the amount of received light decreases. If the thickness exceeds 250 μm, the strength of the lower substrate 1 becomes weak, and it becomes difficult to form a pattern such as the groove b and the groove c, so that handling becomes difficult. More preferably, the upper end 4t of the reflection surface 4 is located higher than the V-grooves a, b, and c.

The reflecting surface 4 is preferably inclined by about 45 ° with respect to the main surface of the lower substrate 1, in which case the reflected light is reflected substantially vertically upward. When the lower substrate 1 is made of silicon and the reflection surface 4 is formed by anisotropic etching, the (100) plane is 9 to 12 ° with respect to the main surface of the lower substrate 1 with the <110> direction as an axis. By inclining, the (111) plane which is the reflecting surface 4 can be inclined by about 45 ° with respect to the main surface. Outside the angle range, the amount of light that is not reflected vertically upward increases, and the amount of light received by the PD 20 decreases.

In the present invention, the Fresnel zone lens 2
Numeral 1 condenses light and increases the light transmittance so that more light can be converged on the PD 20. For example, when the upper substrate 2 is made of silicon that is transparent to infrared light, SiO ₂ , TiO _2, or the like is formed on the upper substrate 2 and the pitch is changed from the center to the outside by photolithography. A concentric resist pattern is formed, and can be manufactured by a reactive ion etching method, an electron beam etching method, a laser beam etching method, or the like. Further, since the Fresnel zone lens 21 can also function as a dielectric multilayer anti-reflection layer, more light can be collected on the PD 20.

More specifically, when the upper substrate 2 is made of silicon and SiO ₂ is used for the Fresnel zone lens 21 at a wavelength λ = 1.55 μm, first, the SiO _{2 is formed} to a thickness of about 3.
By forming a film having a thickness of 42 μm, etching the film at a maximum of 3.16 μm, and making the thinnest portion 0.26 μm, a transmittance of about 95% can be obtained. This is a value 26% higher than the transmittance of silicon alone of 69%. TiO instead of SiO _{2
When 2} is used, a transmittance of about 87.7% can be obtained when the maximum film thickness is 1.05 μm, the etching film thickness is 0.91 μm, and the film thickness of the thinnest portion is 0.14 μm.

Further, according to the present invention, it is possible to coat the reflection surface 4 with an anti-reflection coating or the like so as to increase the reflectance, prevent light scattering, and absorb unnecessary components. For example, TiO ₂ , SiO ₂ ,
By forming a dielectric layer such as Ge or LiF, it is possible to control the reflectance. First, Ag, A
By forming a metal layer of u, Pt or the like as a reflection layer and then laminating the above-mentioned dielectric layer, the reflectance can be further increased.

Further, a dielectric layer having a thickness for enhancing reflection is formed at a spot portion of the laser beam on the reflection surface 4 and a dielectric layer having a thickness for reducing reflection is provided at a portion other than the spot portion. The required reflection at the spot portion is enhanced, and other stray light and scattered light can be attenuated. Further, the reflectance of a specific wavelength can be controlled by the configuration of the metal reflection layer and the dielectric layer. For example, in the case of a two-layer structure of an Ag reflection layer and a TiO ₂ layer, when λ = 1.31 μm, When the thickness of the TiO ₂ layer is 0.23 μm, the reflectance is about 98.3%, and when the thickness of the TiO ₂ layer is 0.10 μm, the reflectance is about 88.3%. Thus, the reflectance can be controlled by about 10%. When λ = 1.55 μm,
With a TiO ₂ layer thickness of 0.27 μm, the reflectance is maximum, and the TiO ₂
The reflectivity can be minimized at a layer thickness of 0.12 μm.

The lower substrate 1 of the optical module M1 of the present invention is manufactured by the following steps. The light emitting element mounting portion of the lower substrate 1 and the fixing surface of the optical fiber 17 are formed in advance so as to be lower than the upper end 4t of the reflecting surface 4 by etching. Next, V grooves a, grooves c, and grooves 3 for the reflection surface 4 are formed by anisotropic etching. The electrode 9 is formed by a photolithography method and an evaporation method. Then, the grooves b and 8 are formed by a dicing method.

The upper substrate 2 is manufactured by the following steps. The surface of the upper substrate 2 other than the surface where the V-groove a1 exists is etched in advance. Next, V-grooves a1 and c1 are formed by an anisotropic etching method. The electrode 14 is formed by photolithography and vapor deposition, and the Fresnel zone lens 21 is provided by photolithography and etching. Then, a groove b1 is formed by a dicing method.

The electrodes 9 and 14 are made of Ti / Pt /
A three-layer structure such as Au and a two-layer structure such as Cr / Au are preferable, and these have excellent long-term reliability and strong adhesion strength.

7 to 10 show another embodiment, FIG. 7 is a plan view of the optical module M2, and FIG. 8A is a line AA 'of FIG. 7 (the laser beam emitted from the LD 15). FIG. 8B is a cross-sectional view taken along the optical axis of FIG.
8C is a cross-sectional view taken along line CC ′ of FIG. 7, FIG. 9 is a plan view of the upper substrate 2, and FIG.
9 is a sectional view taken along the line AA 'in FIG. 9, FIG. 10B is a sectional view taken along the line BB' in FIG. 9, and FIG. 10C is a sectional view taken along the line CC 'in FIG. .

In this optical module M2, the lower substrate 1 is the same as the above-mentioned optical module M1, and instead of the Fresnel zone lens 21, the converging lens for the upper substrate 2 is a spherical lens 19 and a taper for installing the spherical lens 19. Is provided. The through-hole d has an inverted trapezoidal cross-sectional shape by being formed by an anisotropic etching method. In this embodiment, since the spherical lens 19 is used, the upper substrate 2 does not necessarily have to have translucency, and the through hole d may have a cross-sectional shape such as an inverted conical shape. . In this example, since light passes through the through-hole d, the loss of light is small. However, the thickness of the upper substrate 2 is larger than that of the optical module M1, and it takes time to form the through-hole d.

Thus, according to the present invention, light can be extracted almost completely vertically upward, and an extremely efficient optical connection is realized. In addition, since the lid is not required, the number of components is reduced, and since the light emitting / receiving element is mounted on the upper portion of the substrate, wiring by wire bonding or the like is facilitated and workability is improved. Further, a Fresnel zone lens for condensing reflected light on the upper substrate can be formed by a film forming technique, and a spherical lens for condensing reflected light is not required. It has the function and effect of becoming tall.

It should be noted that the present invention is not limited to the above embodiment, and various changes may be made without departing from the scope of the present invention.

[0029]

Embodiments of the present invention will be described below.

(Example) The lower substrate 1 of the optical module M1 of FIG. 1 was manufactured by the following steps (1) to (4).

(1) Using the lower substrate 1 made of silicon and having a thickness of 1 mm, the surface on which the electrode 9 is formed and the surface on which the V-groove a is present are etched using an aqueous solution of potassium hydroxide to form the reflecting surface 4. Lower than the upper end 4t. At that time, the ball lens 1
8 is about 150 μm when the diameter is 600 μm,
By etching about 210 μm at 0 μm,
The light returned from the optical fiber 17 can be applied to the reflection surface 4 without being attenuated, and can enter the PD 20. L
The optical axis of D15 was 8 μm higher than the LD15 mounting surface, and the height from the V-groove a forming surface was also 8 μm. Also,
In this embodiment, all the depths are depths from the optical axis.

(2) Thereafter, the V-grooves a and c were similarly anisotropically etched with an aqueous potassium hydroxide solution. The depth of the groove c is determined by the spherical lens 18. When the diameter of the spherical lens 18 is 600 μm, the depth is about 300 μm and the diameter is 8 μm.
When it is 00 μm, it is about 400 μm. The V-groove a had a depth of 108 μm and a width on the main surface of the lower substrate 1 of 142 μm.

(3) An electrode 9 made of Cr / Au was formed by photolithography and vapor deposition.

(4) The grooves b and 8 were formed by dicing. The groove b has a depth of 510 μm, the width on the main surface of the lower substrate 1 is 50 μm, and the groove 8 has a depth of 400 μm.
m, the width of the main surface of the lower substrate 1 is 100 to 400 μm, and is 200 μm in this embodiment.

The upper substrate 2 is formed by the following steps (5) to (5).
It was produced by (8).

(5) Using the upper substrate 2 made of silicon and having a thickness of 800 μm, the surface other than the surface where the V-groove a1 is present was etched in advance to reduce the height of the surface. At this time, the diameter of the spherical lens 18 having a diameter of 600 μm is reduced by about 150 μm, and the diameter of the spherical lens 18 having a diameter of 800 μm is reduced by about 21 μm.
Reduce by 0 μm.

(6) Next, V-grooves a1 and c1 were formed by anisotropic etching using an aqueous solution of potassium hydroxide.
At this time, if the diameter of the spherical lens 18 is 600 μm,
The inverted quadrangular pyramid-shaped groove c1 has a depth of 362 μm, and is 511.5 μm × 511.5 μm square on the main surface of the upper substrate 2.
The groove a1 had a depth of 108 μm, and the width on the main surface of the upper substrate 2 was 142 μm. When the diameter of the spherical lens 18 is 800 μm, the groove c1 has a depth of 462 μm and the upper substrate 2
The size of the main surface is 653.0 μm × 653.0 μm square.

(7) The electrode 14 was formed by photolithography and vapor deposition, and the Fresnel zone lens 21 was provided by photolithography and etching. At this time, the operating wavelength λ = 1.55 μm and SiO 2
₂ was used for the Fresnel zone lens 21. First, SiO
₂ was formed to a film thickness of about 3.42 μm, etched at a maximum of 3.16 μm, and the thinnest portion was made 0.26 μm, whereby a transmittance of about 95% was obtained. Fresnel zone lens 21
Is about 0.6 mm, and λ = 1.5
When 5 μm and NA (aperture ratio) = 0.3, the total number of zones is 29, and the inner radius rm of the m-th zone from the center is rm =
(2mλf) ^1/2 (where λ is the wavelength and f is the focal length).

(8) Then, a groove b1 was formed by a dicing method. The depth was 510 μm, and the width on the main surface of the upper substrate 2 was 510 μm.

The groove 3 for the reflecting surface 4 is formed so that the (111) plane forming the reflecting surface 4 is inclined by about 45 ° with respect to the main surface of the lower substrate 1 after anisotropic etching. Anisotropic etching was performed using a silicon crystal whose (100) plane was inclined by 10 ° with respect to the main surface of the lower substrate 1 with the <110> direction as an axis. The reflective surface 4 is made of Ag.
Reflective layer (lower layer) TiO ₂ layer (upper layer) provided, TiO ₂
Assuming that the thickness of the layer is 0.27 μm, the reflectance for λ = 1.55 μm is 97.9%.

The optical filter 1 is mounted on the lower substrate 1.
6, the LD 15 is mounted, and the upper substrate 2 has an optical fiber 17,
After mounting the spherical lens 18 and the PD 20, respectively, the two substrates were superposed and bonded and fixed with an ultraviolet curing resin or a thermosetting resin. After that, wire bonding of the LD 15 and the PD 20 could be performed at once. In the present embodiment, the optical filter 16 is a wavelength selection filter, and transmits the light having a wavelength of 1.31 μm from the LD 15.
The light having a wavelength of 1.55 μm from the optical fiber 17 is reflected.

The optical module M2 of FIG. 7 was manufactured in the same manner as described above except that the upper substrate 2 was provided with a through hole d for installing a spherical lens. In this case, the thickness of the upper substrate 2 is 1
mm, but the optical loss was smaller than that of the optical module M1.

11A and 11B show a comparative example, wherein FIG. 11A is a plan view of the lower substrate 1, FIG. 11B is a cross-sectional view taken along the line AA 'of FIG. 11A, and FIG. It is sectional drawing in the BB 'line. The description of the upper substrate 2 is omitted.

As shown in FIG. 5C, the upper end 4 of the reflection surface 4 and the LD 15 mounting surface are substantially at the same height.
The light reflected by the optical filter 16 was not completely reflected by the reflection surface 4, and about half of the light was lost. Also, the reflection surface 4
Since no coating or the like was provided, the reflectance was as low as about 43.3%.

[0045]

According to the present invention, a light emitting element mounting portion, an optical fiber fixing V groove a provided at a position facing the light emitting element, and a light emitting element and V groove a are provided on the upper main surface of the lower substrate. A groove b for installing an optical filter formed on the optical axis between the optical filter and a reflecting surface for reflecting light reflected by the optical filter substantially vertically upward, and the light emitting element mounting surface is located at a position higher than the upper end of the reflecting surface. Is also on the reflection surface side, and on the lower main surface of the upper substrate, a condensing lens and a light receiving element for condensing light reflected by the reflection surface are installed, and the lower main surface of the upper substrate and the upper side of the lower substrate By superimposing the main surface, light can be extracted almost vertically upward without reducing the amount of light. As a result, extremely high-efficiency optical connection can be performed, and the upper substrate is also used as the lid. This eliminates the need for a separate lid, reducing the number of parts, and There becomes easy wiring by wire bonding or the like because it is mounted on the substrate top.

Further, when a Fresnel zone lens formed by a thin film forming method is provided as a condenser lens on the upper substrate, there is an effect that the upper substrate can be made extremely thin while maintaining high light transmittance. When a spherical lens is provided as the condenser lens, light loss can be further reduced.

[Brief description of the drawings]

FIG. 1 is a plan view of an optical module M1 of the present invention.

FIG. 2A is a sectional view taken along line AA ′ of FIG. 1;
FIG. 2B is a cross-sectional view taken along line BB ′ of FIG. 1, and FIG. 2C is a cross-sectional view taken along line CC ′ of FIG.

FIG. 3 is a plan view of the lower substrate 1 of the present invention.

FIG. 4A is a sectional view taken along line AA ′ of FIG. 3;
FIG. 3B is a cross-sectional view taken along line BB ′ of FIG. 3, and FIG. 3C is a cross-sectional view taken along line CC ′ of FIG.

FIG. 5 is a plan view of the upper substrate 2 of the present invention.

6A is a cross-sectional view taken along line AA ′ in FIG.
(B) is a cross-sectional view taken along the line BB 'in FIG. 5, and (c) is a cross-sectional view taken along the line CC' in FIG.

FIG. 7 shows another embodiment of the present invention, in which an optical module M2 is provided.
FIG.

FIG. 8A is a cross-sectional view taken along line AA ′ of FIG.
(B) is a cross-sectional view taken along the line BB 'in FIG. 7, and (c) is a cross-sectional view taken along the line CC' in FIG.

FIG. 9 is a plan view of the upper substrate 2 of the optical module M2.

FIG. 10A is a cross-sectional view taken along line AA ′ of FIG. 9;
(B) is a cross-sectional view taken along the line BB 'in FIG. 9, and (c) is a cross-sectional view taken along the line CC' in FIG.

11A and 11B show a comparative example, in which FIG. 11A is a plan view of the lower substrate 1, FIG. 11B is a cross-sectional view taken along line AA ′ of FIG.
(C) is a sectional view taken along line BB 'of (a).

FIG. 12 is a partial sectional view of a conventional semiconductor laser device.

[Explanation of symbols]

 1: lower substrate 2: upper substrate 3: inverted trapezoidal groove 4: reflective surface 8: groove 9: LD electrode 14: PD electrode 15: LD 16: optical filter 17: optical fiber 20: PD 21 : Fresnel zone lens

Claims (2)

[Claims] A light-emitting element mounting portion provided on an upper main surface of the lower substrate and an optical fiber fixing portion provided at a position facing the light-emitting element. V groove a,
A groove b for installing an optical filter formed on the optical axis between the light-emitting element and the V-groove a; a reflecting surface for reflecting light reflected by the optical filter substantially vertically upward; The element mounting portion is located closer to the reflection surface than the upper end of the reflection surface, and a condensing lens and a light receiving element for collecting light reflected by the reflection surface are installed on the lower main surface of the upper substrate. An optical module characterized in that a side main surface and an upper main surface of a lower substrate are overlapped. 2. A condensing lens provided on a main surface of the upper substrate is a Fresnel zone lens or a spherical lens.
An optical module as described.