JP2002258112A - Optical communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical communication system that uses, as a light emitting source, a surface-emitting semiconductor laser element chip operable with a low voltage and a low oscillation threshold current, etc., and that can obtain superior optical coupling of this laser element and an optical fiber. SOLUTION: The optical fiber which is optically coupled to the light emitting part of the laser chip is made to be mechanically connected by making the fiber axial direction to be in a pressed state in the direction toward the light emitting part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser used for optical communication and the like and an optical communication system therefor, and more particularly to a so-called surface which emits light in a direction perpendicular to the surface of a semiconductor substrate used for manufacturing the semiconductor laser. The present invention relates to an optical communication system in which a plurality of laser elements are formed using a light emitting laser to enable large-capacity communication.

[0002]

2. Description of the Related Art A surface emitting semiconductor laser emits laser light in a vertical direction from the surface of a substrate, so that two-dimensional parallel integration is possible, and the spread angle of the output light is relatively narrow (about 10 degrees). Therefore, it is easy to couple with an optical fiber and easy to inspect the element.
Therefore, in particular, development as an element suitable for configuring an optical transmission module (optical interconnection device) of a parallel transmission type has been actively conducted. The immediate application of the optical interconnection device is parallel connection between housings of computers and the like and between boards, as well as short-distance optical fiber communication, but large-scale computer networks and long distances are expected applications in the future. There is a trunk system for distance and large-capacity communication.

Generally, a surface emitting semiconductor laser is made of GaAs.
Or, it is common to comprise an active layer made of GaInAs, and an optical resonator consisting of an upper semiconductor distributed Bragg reflector disposed above and below the active layer and a lower semiconductor distributed Bragg reflector on the substrate side. However, since the length of the optical resonator is significantly shorter than that of the edge emitting semiconductor laser, it is necessary to set the reflectivity of the reflecting mirror to an extremely high value (99% or more) so as to easily cause laser oscillation. There is. For this reason, a semiconductor distributed Bragg reflector formed by alternately laminating a low-refractive-index material made of AlAs and a high-refractive-index material made of GaAs with a period of 1/4 wavelength is usually used.

By the way, as described above, a long wavelength band laser having a laser wavelength of 1.1 μm or more used for optical communication, for example, a long wavelength band having a laser wavelength of 1.3 μm or 1.55 μm. In the laser, InP is used for the production substrate and InGaAsP is used for the active layer. However, the lattice constant of InP of the substrate is large, and a large difference in the refractive index cannot be obtained with a reflecting mirror material that matches the substrate. Must be more than pairs. Another problem with the semiconductor laser formed on the InP substrate is that the characteristics greatly change with temperature. For this reason, it is necessary to add a device for keeping the temperature constant, and it is difficult to use the device for general purposes such as consumer use. Light emitting semiconductors have not yet been put to practical use.

As an invention made to solve such a problem, one disclosed in Japanese Patent Application Laid-Open No. 9-237942 is known. According to this, a GaAs substrate is used as a production substrate, and a semiconductor layer made of AlInP that can be lattice-matched with the substrate is used as a low refractive index layer of at least one of the semiconductor distributed Bragg reflectors in the lower part on the substrate side. A semiconductor layer made of GaInNAs is used as a high refractive index layer of at least one of the lower and upper semiconductor distributed Bragg reflecting mirrors so that a larger refractive index difference is obtained than in the prior art. It is to realize a mirror.

Further, GaInNAs is used as a material for the active layer. This is because the band gap (forbidden band width) is increased from 1.4 eV to 0 eV by increasing the N composition.
0.85 μm
This is because it can be used as a material that emits a longer wavelength. In addition, since lattice matching with the GaAs substrate is possible, the semiconductor layer made of GaInNAs is 1.3 μm.
Reference is also made to the fact that it is preferable as a material for long-wavelength surface emitting semiconductor lasers in the m-band and 1.55 μm band.

[0007] However, conventionally, this only suggests the possibility of realizing a surface emitting semiconductor laser in a wavelength band longer than 0.85 µm, and such a device is not actually realized. This is because the basic configuration is almost theoretically determined, but a more specific configuration for realizing stable laser emission is still unknown.

As an example, a semiconductor distributed Bragg reflector formed by alternately laminating a low-refractive-index material made of AlAs and a high-refractive-index material made of GaAs at a period of 1/4 wavelength as described above is used. Or a device using a semiconductor layer made of AlInP, which is lattice-matched to the same substrate as the low refractive index layer of the semiconductor distributed Bragg reflector, as disclosed in JP-A-9-237942. The laser element does not emit light at all,
Alternatively, even if light is emitted, the light emission efficiency is low, which is far from a practical level. This is because the material containing Al is chemically very active, and crystal defects due to Al are likely to occur. In order to solve this problem, it is necessary to use a GaInNP containing no Al as disclosed in Japanese Patent Application Laid-Open Nos. 8-340146 and 7-307525.
There is a proposal for forming a semiconductor distributed Bragg reflector from GaAs and GaAs. However, the refractive index difference between GaInNP and GaAs is about half of the refractive index difference between AlAs and GaAs, and the number of stacked reflectors is very large, making it difficult to manufacture.

That is, at present, optical fiber communication is expected in a computer network or the like. However, a long wavelength band surface emitting semiconductor laser having a laser wavelength of 1.1 μm to 1.7 μm and a communication system using the same can be used. It does not exist and its appearance is longing for.

[0010]

According to the present invention, a laser oscillation wavelength used for such optical communication or the like is 1.1 μm or more.
1. Field of the Invention The present invention relates to a long-wavelength surface emitting semiconductor laser having a wavelength of 1.7 μm and an optical communication system using the same. Another object of the present invention is to obtain good optical coupling between the laser element and the optical fiber.

Similarly, the second object is to use a long-wavelength surface emitting semiconductor laser device chip having a laser oscillation wavelength of 1.1 μm to 1.7 μm, which can be used stably, as a light emitting light source. It is to obtain a good optical coupling of the fiber.

A third object is to obtain good optical coupling between optical fibers in such an optical communication system.

A fourth object is to obtain good optical coupling between optical fibers in such an optical communication system by a simple principle / structure.

A fifth object of the present invention is to propose another structure for obtaining good optical coupling between optical fibers by a simple principle / structure in such an optical communication system.

A sixth object of the present invention is to propose a configuration for obtaining good optical coupling between optical fibers in such an optical communication system by a principle / structure completely different from the conventional one.

[0016]

According to the present invention, in order to achieve the above object, first, in a laser chip and an optical communication system connected to the laser chip, the laser chip has an oscillation wavelength of 1.1 μm to 1 μm. 0.7 μm, and the light-generating active layer is a layer whose main element is Ga, In, N, As or a layer consisting of Ga, In, As. What is claimed is: 1. A surface-emitting type semiconductor laser device chip having a resonator structure including a reflecting mirror provided at a lower portion, wherein the reflecting mirror periodically changes the refractive index of a material layer constituting the reflecting mirror to be small / large and is incident. A semiconductor distributed Bragg reflector for reflecting light by light wave interference, and the material layer having a small refractive index is made of Al _x Ga _{1 -x} As.
(0 <x ≦ 1) and then, the material layer of the refractive index is large is Al _y
A reflecting mirror having Ga _1-y As (0 ≦ y <x ≦ 1),
And a material layer Al _z Ga _{1 -z} As (0 ≦ y <z) in which the refractive index takes a value between small and large between the material layers with small and large refractive indexes.
<X ≦ 1) An optical communication system using a surface emitting semiconductor laser element chip provided with <x ≦ 1) as a light emitting light source, wherein an optical fiber optically coupled to a light emitting unit of the laser chip includes:
The direction of the fiber axis was pressed in the direction of the light emitting section, and the fiber axis was mechanically connected.

Secondly, in a laser chip and an optical communication system connected to the laser chip, the laser chip has an oscillation wavelength of 1.1 μm to 1.7 μm, and an active layer for generating light includes a main element. Is Ga, In, N, As
Or a layer made of Ga, In, As, and a surface emitting semiconductor laser device chip having a resonator structure including reflectors provided above and below the active layer in order to obtain a laser beam. The reflector is a semiconductor distributed Bragg reflector in which the refractive index of the material constituting the reflector changes periodically as small / large and reflects incident light by light wave interference. Al _x Ga _1-x
As (0 <x ≦ 1), the material having a large refractive index is Al
a reflecting mirror with _y Ga _1-y As (0 ≦ y <x ≦ 1),
GaInP or Ga between the active layer and the reflector.
An optical communication system using a surface-emitting type semiconductor laser device chip provided with a non-radiative recombination preventing layer made of InPAs as a light source, wherein the optical fiber optically coupled to a light-emitting portion of the laser chip comprises: The fiber axis was pressed in the direction of the light-emitting portion so as to be mechanically connected.

Thirdly, in the first and second optical communication systems, two or more optical fibers constituting the optical communication system may be connected to each other when the optical fibers are optically coupled to each other. The fiber axes were pressed against each other and mechanically connected.

Fourth, in the first to third optical communication systems, the pressed state is created by the elastic force of the optical fiber itself.

Fifth, in the first to third optical communication systems, the pressed state is formed by an elastic body provided in a unit for mechanically connecting the optical fiber. .

Sixth, in the fifth optical communication system, the elastic body is a shape memory material,
When assembling the unit, the shape memory material is assembled at a temperature at which the shape memory material is deformed, and then, by returning the temperature, the shape memory material regains the memory shape and has a structure in which an elastic force is generated. .

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an example of a long-wavelength surface emitting semiconductor laser having a small laser oscillation wavelength of 1.1 to 1.7 .mu.m, which is a light emitting element applied to the optical communication system of the present invention, having a small transmission loss. This will be described with reference to FIG. As described above, a long-wavelength surface emitting semiconductor laser having a laser oscillation wavelength of 1.1 μm to 1.7 μm to which the present invention is conventionally applied only suggests the possibility. The material, as well as the more specific and detailed composition, were unknown. In the present invention, a material such as GaInNAs is used for the active layer, and a more specific configuration is clarified. The details are described below.

In the present invention, n-Ga having a plane orientation of (100) is used.
On the As substrate, n-Al _x Ga _{1 -x} A with a thickness (thickness of λ / 4) of 発 振 of the oscillation wavelength λ in each medium.
s (x = 1.0) (low refractive index layer to low refractive index layer) and n−
An n-semiconductor distributed Bragg reflector (AlAs / GaAs lower semiconductor distributed Bragg reflector) in which 35 cycles of Al _y Ga _1-y As (y = 0) (high refractive index layer to high refractive index layer) are alternately stacked. And n-Ga _x In _1-x P _{y having} a thickness of λ / 4 is formed thereon.
As _1-y (x = 0.5, y = 1) layers were laminated. In this example _{n-Ga x In 1-x} P y As 1-y (x = 0.5, y =
1) The layer is also a part of the lower reflecting mirror and is a low refractive index layer (a layer having a small refractive index). And undoped lower G on it
an aAs spacer layer, a multiple quantum well active layer including an active layer (quantum well active layer), which is a three-layer Ga _x In _1-x As quantum well layer, and a GaAs barrier layer (20 nm), and an undoped upper GaAs spacer layer. Are stacked to form a resonator having a thickness of one wavelength of the oscillation wavelength λ (thickness of λ) in the medium.

In addition, C (carbon) doped p-
Ga _x In _{1-x Py} As _1-y (x = 0.5, y = 1) layer and Z
A periodic structure (one cycle) in which n-doped p-Al _x Ga _1-x As (x = 0) is alternately stacked with a thickness of １ ／ times the oscillation wavelength λ in each medium is stacked. C-doped p-Al _x Ga _{1 -x} As (x = 0.9) and Zn-doped p
A semiconductor distributed Bragg reflector (a periodic structure (25 periods) in which -Al _x Ga _{1 -x} As (x = 0) is alternately stacked with a thickness of １ ／ times the oscillation wavelength λ in each medium; Al _0.9 Ga _0.1 As / GaAs upper semiconductor distributed Bragg reflector)
Is formed. In this example _{p-Ga x In 1-x} P y As
_{The 1-y} (x = 0.5, y = 1) layer is also a part of the upper reflecting mirror and is a low refractive index layer (a layer having a small refractive index). Here, both the upper and lower reflectors are formed by alternately laminating a low refractive index layer (a layer having a low refractive index) / a high refractive index layer (a layer having a high refractive index). In addition, a material layer Al _z Ga _{1 -z} As having a refractive index between a small value and a large value (0 ≦ y <
z <x ≦ 1). FIG. 2 shows a material layer AlzGa1-zAs having a refractive index between a small refractive index and a large refractive index between a low refractive index layer (low refractive index layer) and a high refractive index layer (high refractive index layer).
FIG. 1 shows a part of a semiconductor distributed Bragg reflector provided with (0 ≦ y <z <x ≦ 1) (in FIG. 1, the illustration is omitted because the figure becomes complicated).

Conventionally, it has been studied to provide such a material layer for a semiconductor laser having a laser wavelength of 0.85 μm band, but it is still in the study stage, and the material and the thickness thereof are not described in detail. Not considered. Further, the laser oscillation wavelength as in the present invention is 1.1 μm to 1.7 μm.
No consideration has been given to a long-wavelength surface emitting semiconductor laser having a wavelength of m. The reason for this is that this field (a long-wavelength surface emitting semiconductor laser having a laser oscillation wavelength of 1.1 μm to 1.7 μm) is a new field, and little research has yet been made.

The present inventor has quickly noticed the usefulness of this field (a long-wavelength surface emitting semiconductor laser having a laser oscillation wavelength of 1.1 μm to 1.7 μm and optical communication using the same).
In order to realize it, we studied diligently.

In such a material layer, the refractive index of the material layer is changed continuously or stepwise by controlling the gas flow rate at the time of formation and changing the Al composition continuously or stepwise. And formed.

More specifically, Al _z Ga _{1 -z} As (0 ≦
(y <z <x ≦ 1) The layer is formed so that the value of z of the layer changes from 0 to 1.0, that is, the ratio of Al to Ga gradually changes, such as GaAs to AlGaAs to AlAs. This is created by controlling the gas flow during layer formation as described above. Al and G
The ratio a may be formed so as to change continuously as described above, or the same effect can be obtained even if the ratio changes stepwise.

The reason for providing such a material layer is to solve the problem that the electrical resistance of the p-semiconductor distributed Bragg reflector, which is one of the problems of the distributed Bragg reflector, is high. This is due to the hetero barrier generated at the interface between the two types of semiconductor layers constituting the semiconductor distributed Bragg reflector. However, as in the present invention, the interface between the low refractive index layer and the high refractive index layer is changed from one composition to the other. It is possible to suppress the generation of the hetero barrier by changing the Al composition gradually to the composition and changing the refractive index.

The material layer AlzGa1-zAs having such a refractive index between a small value and a large value (0 ≦ y <z <x ≦
1) The laser oscillation wavelength as in the present invention is 1.1 μm or more.
In the case of a long-wavelength surface emitting semiconductor laser of 1.7 μm, 5n
The thickness is preferably from m to 50 nm. If the thickness is smaller than this, there is a problem that the resistance becomes large and current does not easily flow, and the element generates heat and the driving energy becomes high. If the thickness is large, the resistance becomes small, which is advantageous in terms of heat generation of the element and driving energy. However, there is a problem that the reflectance cannot be obtained, and the optimum range (thickness of 5 nm to 50 nm) as described above. You need to choose As described above, it has been considered to provide such a material layer for a conventional semiconductor laser having a laser wavelength of 0.85 μm band. However, the laser oscillation wavelength of the present invention is 1.1 μm to 1.7 μm. In the case of a long-wavelength band surface emitting semiconductor laser, it is more effective. Because, for example, the equivalent reflectance (for example, 99.5%
Above) to obtain 1.1 μm from the 0.85 μm band.
In the case of the m band to 1.7 μm band, such a material layer can be approximately doubled, so that the resistance value of the semiconductor distributed Bragg reflector can be reduced, and the operating voltage, oscillation threshold current and the like can be reduced. This is advantageous in terms of prevention of heat generation of the laser element, stable oscillation, and low energy driving.

That is, providing such a material layer on a semiconductor distributed Bragg reflector is particularly effective in the case of a long-wavelength surface emitting semiconductor laser having a laser oscillation wavelength of 1.1 μm to 1.7 μm as in the present invention. It can be said that it is a device. In addition, as an example of a more detailed examination result for obtaining an effective reflectance, for example, in a 1.3 μm band surface emitting laser device, A
_{l x Ga 1-x As (} x = 1.0) ( low refractive index layer-refractive index small layer) and _{Al y Ga 1-y As (} y = 0) ( a layer of the high refractive index layer-refractive index large ) Are stacked for 20 periods, the thickness of the Al _z Ga _{1 -z} As (0 ≦ y <z <x ≦ 1) layer in which the reflectivity of the semiconductor distributed Bragg reflector becomes 99.7% or less is 3
0 nm. The wavelength band in which the reflectance is 99.5% or more is 53 nm. When the reflectance is designed to be 99.5% or more, it is only necessary to control the film thickness by ± 2%. Therefore, 10nm, 20nm,
A prototype of a 30 nm device was fabricated. As a result, a 1.3 μm surface emitting laser device capable of keeping the reflectance to a practically acceptable level and reducing the resistance of the semiconductor distributed Bragg reflector was realized. Laser oscillation succeeded. Other configurations of the prototyped laser element are as described below.

In the multilayer mirror, there is a band having a high reflectance including the design wavelength (assuming that the film thickness can be completely controlled). It is referred to as a high-reflectance band (including a region where the reflectivity is equal to or more than a required value for a target wavelength). This is the region where the reflectance at the design wavelength is the highest and decreases very little as the wavelength increases. It drops off sharply from some area. Originally, it is necessary to completely control the film thickness of the multilayer mirror at the atomic layer level so that the reflectance is higher than the required reflectance for the target wavelength. But actually ± 1
Since a film thickness error of about% occurs, the target wavelength deviates from the wavelength having the highest reflectance. For example, if the target wavelength is 1.3
In the case of μm, when the film thickness control is shifted by 1%, the wavelength having the highest reflectance is shifted by 13 nm. Therefore, it is desirable that the band of the high reflectance (here, the region where the reflectance is equal to or more than a required value with respect to a target wavelength) is wide. However, thickening the intermediate layer tends to narrow this band.

As described above, in the long-wavelength surface emitting semiconductor laser having a laser oscillation wavelength of 1.1 μm to 1.7 μm as in the present invention, the configuration of such a semiconductor distributed Bragg reflector is devised and optimized. Since the resistance value can be reduced while maintaining a high reflectance, the operating voltage, the oscillation threshold current, and the like can be reduced, so that heat generation of the laser element, stable oscillation, and low-energy driving can be achieved.

Returning again to FIG. 1, the uppermost p-Al _x G
The a _1-x As (x = 0) layer also has a role as a contact layer (p-contact layer) for making contact with the electrode.

Here, the In composition x of the quantum well active layer is 3
9% (Ga0.61In0.39As). The thickness of the quantum well active layer was 7 nm. The quantum well active layer is made of GaAs.
It had a compression strain of about 2.8% with respect to the substrate.

The whole surface-emitting type semiconductor laser was grown by MOCVD. In this case, no lattice relaxation was observed. The materials constituting each layer of the semiconductor laser include TMA (trimethylaluminum), TMG (trimethylgallium), TMI (trimethylindium),
AsH ₃ (arsine) and PH ₃ (phosphine) were used. H ₂ was used as a carrier gas. In the case where the strain is large as in the active layer (quantum well active layer) of the device shown in FIG. here,
The GaInAs layer (quantum well active layer) is grown at 550 ° C. The MOCVD method used here has a high degree of supersaturation and is suitable for crystal growth of a high strain active layer. In addition, high vacuum is not required as in the MBE method, and the supply flow rate and supply time of the source gas may be controlled. In this example, a portion outside the current path was irradiated with protons (H ⁺ ) to form an insulating layer (high-resistance portion) to form a current narrowing portion.

In this example, a p-side electrode is formed on the p-contact layer, which is the uppermost layer of the upper reflector and is a part of the upper reflector, except for the light emitting portion. An n-side electrode was formed. In this example, the active region (in this embodiment, a resonator composed of the upper and lower spacer layers and the multiple quantum well active layer) sandwiched between the upper and lower reflectors and into which carriers are injected and recombined, has an active region. material containing al (percentage of group III 1% or more) without using a further layer closest to the active layer of the low refractive index layer of the lower and upper reflector _{Ga x in 1-x P y} As 1 _-y (0 <x <1, 0 <y ≦
The non-radiative recombination preventing layer of 1) is used. Carriers are confined between the low-refractive index layers of the upper and lower reflectors, which are closest to the active layer and have a wide gap, so that only the active region contains no Al (1% or less of group III).
If the low refractive index layer (wide gap layer) of the reflector in contact with the active region is made to contain Al even when the carrier is injected, non-radiative recombination occurs at this interface when carriers are injected and recombined. Luminous efficiency is reduced. Therefore, it is desirable that the active region be formed of a layer containing no Al.

The Ga _x In _{1-x Py} As _1-y (0 <x
The non-radiative recombination preventing layer composed of <1, 0 <y ≦ 1)
Its lattice constant is smaller than that of a GaAs substrate and has tensile strain.

In the epitaxial growth, the growth is performed by reflecting the information of the base, and if there is a defect on the surface of the substrate, it goes up to the growth layer. However, it is known that the presence of a strained layer is effective in preventing such defects from climbing.

When the above defects reach the active layer, the luminous efficiency is reduced. In the case of an active layer having a strain, there arises a problem that the critical thickness is reduced and a layer having a required thickness cannot be grown. In particular, when the amount of compressive strain of the active layer is large, for example, 2% or more, or when the thickness of the strained layer is larger than the critical thickness, even if non-equilibrium growth such as low-temperature growth is performed, growth cannot be performed due to the presence of defects. This is particularly problematic. If a strained layer is present, such a defect can be prevented from climbing up, so that the luminous efficiency can be improved, a layer having a compressive strain of 2% or more of the active layer can be grown, or the thickness of the strained layer can be reduced to a critical film. It becomes possible to grow thicker than thick.

The Ga _x In _{1-x Py} As _1-y (0 <x <
1,0 <y ≦ 1) layer also has the role of carrier confinement in which the active region in contact with the active region but, Ga _x an In
_{The 1-x Py} As _1-y (0 <x <1, 0 <y ≦ 1) layer can have a larger band gap energy as the lattice constant decreases. For example, in the case of Ga _x In _1-x P (when y = 1), as x increases and approaches x GaP, the lattice constant increases and the band gap increases. Band gap E
g is a direct transition, Eg (Γ) = 1.351 + 0.643x + 0.786
x ² , and Eg (X) = 2.24 + 0.02x in the indirect transition. Therefore, the active region and Ga _x In _{1-x Py} As _1-y (0
<X <1, 0 <y ≦ 1) The hetero barrier in the layer is large, so that the carrier confinement is good, the threshold current is reduced,
This has the effect of improving temperature characteristics.

Further, the Ga _x In _{1-x Py} As _1-y (0 <
x <1, 0 <y ≦ 1) The non-radiative recombination preventing layer has a larger lattice constant than the GaAs substrate, has a compressive strain, and has a lattice constant of the active layer of Ga _x.
It has a larger compressive strain than the In _{1-x Py} As _1-y (0 <x <1, 0 <y ≦ 1) layer.

The Ga _x In _{1-x Py} As _1-y (0 <x
<1, 0 <y ≦ 1) Since the direction of strain of the layer is the same as that of the active layer, it acts in the direction of reducing the substantial amount of compressive strain felt by the active layer. The larger the strain is, the more easily affected by external factors. Therefore, it is particularly effective when the amount of compressive strain of the active layer is as large as 2% or more, or when it exceeds the critical film thickness.

For example, a surface emitting laser having an oscillation wavelength in the 1.3 μm band is preferably formed on a GaAs substrate, and a semiconductor multilayer mirror is often used for the resonator, and the total thickness is 5 to 8 μm. It is necessary to grow 50 to 80 semiconductor layers before growing the active layer. (On the other hand, in the case of an edge-emitting laser, the total thickness before growing the active layer is about 2 μm, and it is only necessary to grow about three semiconductor layers.) In this case, even if a high-quality GaAs substrate is used, various methods are used. Due to the cause (defects once generated basically creep up in the crystal growth direction and defects are generated at the hetero interface).
The defect density on the surface immediately before the active layer growth is inevitably higher than the defect density on the s substrate surface. If the insertion of a strained layer or the substantial amount of compressive strain felt by the active layer is reduced before the growth of the active layer, the influence of defects on the surface immediately before the growth of the active layer can be reduced. In this example, Al is not included in the active region and at the interface between the reflector and the active region. Therefore, non-radiative recombination due to crystal defects caused by Al during carrier injection is eliminated, and Recombination was reduced.

As described above, it is preferable to apply a structure that does not contain Al at the interface between the reflector and the active region, that is, to provide a non-radiative recombination preventing layer for both the upper and lower reflectors. It is effective even when applied to a reflector. In this example, both the upper and lower reflecting mirrors are semiconductor distributed Bragg reflecting mirrors, but one reflecting mirror may be a semiconductor distributed Bragg reflecting mirror and the other reflecting mirror may be a dielectric reflecting mirror. In the above-described example, only the layer closest to the active layer in the low-refractive index layer of the reflector is Ga _x In _{1-x Py} As _1-y (0 <x <1,
Although a non-radiative recombination prevention layer of 0 <y ≦ 1) is used, a plurality of layers of Ga _x In _{1-x Py} As _1-y (0 <x <1, 0 <y ≦
1) may be a non-radiative recombination preventing layer.

Further, in this example, this idea is applied to the lower reflector between the GaAs substrate and the active layer, and a crystal defect caused by Al, which is a problem at the time of growing the active layer, rises into the active layer. The adverse effect is suppressed, and the active layer can be crystal-grown with high quality. As a result, a surface-emitting type semiconductor laser having high luminous efficiency and sufficient reliability for practical use was obtained. In addition, not all of the low refractive index layers of the semiconductor distributed Bragg reflector but at least a portion closest to the active region is Ga _x In _{1 -x Py} As _{1 -y} (0 <x <
Since only 1, 0 <y ≦ 1) layers, the above-described effect can be obtained without particularly increasing the number of stacked reflectors.

The oscillation wavelength of the surface emitting semiconductor laser manufactured in this manner was about 1.2 μm. GaInAs on a GaAs substrate has a longer wavelength due to an increase in the In composition, but with an increase in the amount of strain. Conventionally, up to 1.1 μm has been considered to be the limit of a longer wavelength (see the document “IEEE Photo”).
onics. Technol. Lett. Vol. 9
(1997) p. 1319-1321 ").

However, as manufactured by the present inventors, a highly strained GaInAs quantum well active layer can be coherently grown thicker than before by a growth method with a high degree of non-equilibrium, such as growth at a low temperature of 600 ° C. or less. Reached 1.2 μm. This wavelength is transparent to the Si semiconductor substrate. Therefore, light transmission through the Si substrate becomes possible in a circuit chip in which an electronic element and an optical element are integrated on the Si substrate.

As apparent from the above description, it was found that a long-wavelength surface-emitting type semiconductor laser can be formed on a GaAs substrate by using GaInAs having a large In composition and a high compression strain for the active layer. As described above, such a surface emitting semiconductor laser can be grown by MOCVD, but other growth methods such as MBE can also be used. Although the triple quantum well structure (TQW) has been described as an example of the stacked structure of the active layer, a structure (SQW, MQW) using a quantum well of another number of wells may be used.

The structure of the laser may be another structure. Although the length of the resonator is set to the thickness of λ, it can be set to an integral multiple of λ / 2. Desirably, it is an integral multiple of λ. Also, an example in which GaAs is used as the semiconductor substrate has been described.
The above concept can be applied even when another semiconductor substrate such as P is used. The period of the reflecting mirror may be another period. In this example, the main elements of the active layer are Ga, In, and A.
s, that is, Ga _x In _{1 -x} As (GaInA
Although the example of the (s active layer) was shown, in order to perform laser oscillation of a longer wavelength, N was added, and the main elements were Ga, In, and
What is necessary is just to make it the layer (GaInNAs active layer) which consists of N and As. By actually changing the composition of the GaInNAs active layer, it was possible to perform laser oscillation in each of the 1.3 μm band and the 1.55 μm band. By examining the composition, a surface emitting laser having a longer wavelength, for example, in the 1.7 μm band can be obtained.

Also, when GaAsSb is used for the active layer,
A 1.3 μm band surface emitting laser can be realized on an aAs substrate. As described above, a semiconductor laser having a wavelength of 1.1 μm to 1.7 μm has not conventionally been available with a suitable material.
By using aInAs, GaInNAs, and GaAsSb, and providing a non-radiative recombination preventing layer, a high-performance surface emitting laser in a long wavelength region of the 1.1 μm to 1.7 μm band where stable oscillation has been difficult in the past. Can be realized.

Next, another configuration of a long wavelength band surface emitting semiconductor laser which is a light emitting element applied to the optical transmitting / receiving system of the present invention will be described with reference to FIG. Also in this case, FIG.
As in the case of (1), an n-GaAs substrate having a plane orientation of (100) is used. N-Al _x Ga _{1 -x} A in a thickness of １ ／ of the oscillation wavelength λ (thickness of λ / 4) in each medium.
An n-semiconductor distributed Bragg reflector (Al _0.9 Ga _0.1 As / GaAs lower reflector) in which s (x = 0.9) and n-Al _x Ga _1-x As (x = 0) are alternately stacked for 35 periods. _{formed, n-Ga x in 1-} x P thickness on the lambda / 4 Part _{y As 1-y (x =} 0.
5, y = 1) layers were laminated. In this example, n-Ga _x In
_{The 1-x Py} As _1-y (x = 0.5, y = 1) layer is also a part of the lower reflector and is a low refractive index layer.

On top of that, undoped lower GaAs
A multi-quantum well active layer (a quantum well active layer) composed of a spacer layer, an active layer (quantum well active layer) which is a three-layer Ga _x In _1-x N _y As _1-y quantum well layer, and a GaAs barrier layer (15 nm). In the example, triple quantum well (TQW)) and undoped upper Ga
An As spacer layer is laminated to form a resonator having a thickness (λ thickness) of one oscillation wavelength in the medium.

Further, a p-semiconductor distributed Bragg reflector (upper reflector) is formed thereon.

The upper reflecting mirror is made of AlA to be a selectively oxidized layer.
s layer is sandwiched between a GaInP layer and an AlGaAs layer by 3λ /
4 low refractive index layer (thickness of (λ / 4-15 nm)
C-doped p-Ga_xIn_1-xP_yAs_1-y(X = 0.5, y
= 1) layer, C-doped p-Al _zGa_1-zAs (z = 1)
Selective oxidation layer (thickness 30 nm), thickness (2λ / 4-15)
nm) C-doped p-Al_xGa_1-xAs layer (x = 0.
9)), a GaAs layer having a thickness of λ / 4 (one period), and C
Doped p-Al_xGa_1-xAs layer (x = 0.9) and p-
Al_xGa_1-xAs (x = 0) layer in each medium
Periodic structure laminated alternately with a thickness of 1/4 times the oscillation wavelength
Structure (22 cycles)
Reflector (Al_0.9Ga_0.1As / GaAs upper reflector). What
Also in this example, since it becomes complicated in FIG. 3, it is illustrated.
Although omitted, the structure of the semiconductor distributed Bragg reflector is omitted.
The structure is a low refractive index layer (low refractive index layer) as shown in FIG.
Between the low refractive index and the high refractive index layer (high refractive index layer)
Material layer Al with a value between_zGa_1-zAs (0 ≦ y <z <
x ≦ 1).

The uppermost p-Al _x Ga _{1 -x} As
The (x = 0) layer also serves as a contact layer (p-contact layer) for making contact with the electrode.

Here, the In composition x of the quantum well active layer is 37
%, And the N (nitrogen) composition was 0.5%. The thickness of the quantum well active layer was 7 nm.

The surface emitting semiconductor laser was grown by MOCVD. The materials constituting each layer of the semiconductor laser include TMA (trimethylaluminum), TM
G (trimethyl gallium), TMI (trimethyl indium), AsH ₃ (arsine), PH ₃ (phosphine), and DMHy (dimethylhydrazine) were used as raw materials for nitrogen. DMHy decomposes at low temperature, so 600
It is suitable for low-temperature growth at a temperature of less than or equal to ° C., and is particularly preferable when growing a quantum well layer having a large strain that requires low-temperature growth. Note that H ₂ was used as a carrier gas.

In this example, the GaInNAs layer (quantum well active layer) was grown at 540 ° C. The MOCVD method has a high degree of supersaturation and is suitable for crystal growth of a material containing N and another V group simultaneously. In addition, high vacuum is not required as in the MBE method, and the supply flow rate and supply time of the source gas may be controlled.

[0060] Further in this example, the predetermined size mesa portion of the _{p-Ga x In 1-x} P y As 1-y (x = 0.5, y =
Until reaching 1) _{layer, p-Al z Ga 1-} z As (z = 1)
The selective oxidation layer is formed by exposing the side surface, and the Al _x Ga _{1 -z} As (z = 1) layer on the side surface is oxidized from the side surface with water vapor to form an Al _x O _y current narrowing layer. .

Finally, the portion removed by mesa etching with polyimide (insulating film) is buried and flattened, the polyimide on the upper reflector is removed, and the p-side electrode is formed on the p-contact layer except for the light emitting portion. And n on the back surface of the GaAs substrate.
Side electrodes were formed.

In this example, the lower part of the layer to be selectively oxidized is
Ga as part of the top reflector_xIn_{1 -x}P_yAs_1-y(0 <
x <1, 0 <y ≦ 1) layers are inserted. For example
In the case of etching, a sulfuric acid-based etchant is used.
For example, the GaInPAs system is an etch to the AlGaAs system.
Ga can be used as a stopping layer._xIn
_1-xP_yAs_1-y(0 <x <1, 0 <y ≦ 1) layer inserted
The high mesa etching for selective oxidation.
Can be strictly controlled. Therefore, uniformity and reproducibility are improved.
Cost can be reduced. Also, the surface-emitting type half of this example
When one-dimensional or two-dimensional integration of conductor lasers (elements)
In this case, good controllability during device fabrication
The uniformity and reproducibility of the device characteristics of each device in the array.
There is an effect that it becomes better. In this example,
Ga that doubles as a etching stop layer_xIn_1-xP_yAs
_1-y(0 <x <1, 0 <y ≦ 1) layer is provided on the upper reflector side.
However, it may be provided on the lower reflecting mirror side.

Also in this example, in the active region (in this embodiment, a resonator composed of the upper and lower spacer layers and the multiple quantum well active layer) sandwiched between the upper and lower reflectors and into which carriers are injected and recombined, No material containing Al is used in the active region, and the lower refractive index layers of the lower and upper mirrors, which are closest to the active layer, are formed of Ga _x In _{1-x Py} As _1-y (0
<X <1, 0 <y ≦ 1). That is, in this example, Al is not included in the active region and at the interface between the reflecting mirror and the active region, so that non-radiative recombination caused by crystal defects caused by Al during carrier injection is reduced. Can be done.

It is preferable to apply a configuration in which Al is not contained at the interface between the reflecting mirror and the active region to the upper and lower reflecting mirrors as in this example, but it is effective to apply it to only one of the reflecting mirrors. . In this example, both the upper and lower reflecting mirrors are semiconductor distributed Bragg reflecting mirrors, but one reflecting mirror may be a semiconductor distributed Bragg reflecting mirror and the other reflecting mirror may be a dielectric reflecting mirror.

Further, also in this example, the same idea as in the example of FIG. 1 is applied to the lower reflector between the GaAs substrate and the active layer, so that crystal defects caused by Al, which becomes a problem when growing the active layer, are used. Of the active layer is suppressed, and crystal growth of the active layer with high quality can be achieved.
Note that such a non-radiative recombination preventing layer forms a part of the semiconductor distributed Bragg reflecting mirror in any of the configurations shown in FIGS. 1 and 3, and thus has a thickness of one of the oscillation wavelength λ in the medium. / 4 times the thickness (thickness of λ / 4). Alternatively, a plurality of layers may be provided.

As is clear from the above description, a surface emitting semiconductor laser having high luminous efficiency and sufficient reliability for practical use was obtained with such a configuration. Also, not all of the low refractive index layers of the semiconductor distributed Bragg reflector, but at least the portion closest to the active region is Ga _x In containing no Al.
_{1-x Py} As _1-y (0 <x <1, 0 <y ≦ 1) is used only as a non-radiative recombination prevention layer, so that the above-described effect can be obtained without particularly increasing the number of stacked reflectors. I was able to.

In addition, even in such a configuration, since the polyimide can be easily embedded, the wiring (p-side electrode in this example) is hardly disconnected, and a device having high reliability can be obtained.

The oscillation wavelength of the surface emitting semiconductor laser manufactured as described above was about 1.3 μm.

In this example, the main elements are Ga, In,
A layer composed of N and As was used as an active layer (GaInNAs
As a result, a long-wavelength surface emitting semiconductor laser could be formed on the GaAs substrate. Further, the current was narrowed by selective oxidation of the selectively oxidized layer containing Al and As as main components, so that the threshold current was low.

According to the current narrowing structure using the current narrowing layer made of the Al oxide film obtained by selectively oxidizing the selectively oxidized layer,
By forming the current narrowing layer close to the active layer, the spread of current can be suppressed, and carriers can be efficiently confined in a minute region that is not exposed to the atmosphere. Further oxidized to Al
By forming an oxide film, the refractive index is reduced, and light can be efficiently confined in a minute region in which carriers are confined by the effect of the convex lens, and the efficiency is extremely improved, and the threshold current can be reduced. In addition, since the current narrowing structure can be easily formed, the manufacturing cost can be reduced.

As is clear from the above description, even in the configuration shown in FIG. 3, a 1.3 μm band surface emitting semiconductor laser can be realized similarly to the case of FIG. Is obtained. The surface emitting semiconductor laser of FIG. 3 can be grown by MOCVD as in the case of FIG. 1, but other growth methods such as MBE can be used. Although DMHy is used as a nitrogen source, activated nitrogen and other nitrogen compounds such as NH ₃ can be used.

Further, the example of the triple quantum well structure (TQW) as the stacked structure of the active layer has been described, but a structure using other quantum wells (SQW, DQW, MQW) or the like can also be used. The structure of the laser may be another structure.

In the surface-emitting type semiconductor laser shown in FIG. 3, by changing the composition of the GaInNAs active layer, 1.
A surface emitting semiconductor laser in the 55 μm band, and even in the longer wavelength 1.7 μm band, is also possible. The GaInNAs active layer may contain other III-V elements such as Tl, Sb, and P. Also, even if GaAsSb is used for the active layer, a 1.3 μm band surface emitting semiconductor laser can be realized on a GaAs substrate.

When GaInAs is used for the active layer,
Conventionally, up to 1.1 μm has been considered to be the limit of increasing the wavelength.
The quantum well active layer can be grown thicker than before, and the wavelength can reach up to 1.2 μm. in this way,
Conventionally, there is no suitable material for the semiconductor laser having a wavelength of 1.1 μm to 1.7 μm, but GaInAs, G
By using aInNAs and GaAsSb and providing a non-radiative recombination prevention layer, a high-performance surface-emitting laser can be realized in the long wavelength region of the 1.1 μm to 1.7 μm wavelength band where stable oscillation has conventionally been difficult. As a result, application to optical communication systems has become possible.

FIG. 4 shows an example in which such a long wavelength band surface emitting semiconductor laser device is formed as a large number of chips on an n-GaAs wafer having a plane orientation of (100), and a laser device chip. In the laser element chip shown here, 1 to n laser elements are formed, and the number n and the arrangement method are determined according to the application.

FIG. 5 shows an example of a communication system using a long-wavelength band surface emitting semiconductor laser. A ferrule for fixing an optical fiber to a laser module equipped with a laser element chip, an adapter housing for accommodating the ferrule together with the optical fiber, It is composed of a bush for fixing the optical fiber, a housing for accommodating the bush, a base for integrally fixing the adapter housing, the laser module and the housing. The length from the point A to the point B of the optical fiber is longer than the fixed length L of the end face of the housing from the laser element chip side end of the adapter housing in the figure.

Specifically, in FIG. 5, when the fixed length L is 1, the length AB of the optical fiber is 1.05. In this way, the optical fiber is bent between the adapter housing and the housing, and the elastic fiber itself is given elasticity so that the optical fiber is moved toward the light emitting portion of the laser element in the axial direction of the optical fiber (leftward in the figure). ) Is pressed so that a force acts on it, and the mechanical connection between the two is stabilized to obtain a good optical coupling. Here, a plastic optical fiber is used as the optical fiber, but a quartz glass fiber whose outer periphery is coated with plastic may be used.

FIG. 6 shows a case where the length of the optical fiber AB is set to 2 when the fixed length L in FIG. 5 is set to 1, and the other configuration is the same as that of FIG. It has a larger elastic force than that of FIG. 5, and the connection between the laser element and the optical fiber becomes stronger.

FIG. 7 shows a ferrule for fixing a tapered split sleeve and an optical fiber, a coil spring and a collar made of a shape memory alloy for applying an axial pressing force to the ferrule,
FIG. 4 is a cross-sectional view of a plug housing that stores a split sleeve, a coil spring, and a collar, an adapter housing that stores a ferrule and a plug housing, and a connector that connects the adapter housing and the plug housing. The elastic force of the initial shape acts on the coil spring in a normal temperature and a heated state, and the coil spring is deformed in a direction in which the coil spring expands due to a change to a lower temperature side, and a force acts on the ferrule in the axial direction of the ferrule. Depending on the design of the connector, the shape can be stored and used so that the coil spring further extends on the high temperature side.

FIG. 8 shows a plug housing for accommodating a tapered split sleeve, a ferrule for fixing an optical fiber, a shape memory alloy leaf spring and a collar for applying an axial pressing force to the ferrule, and a split sleeve, a coil spring and a collar. FIG. 4 is a sectional view of an adapter housing for housing a ferrule and a plug housing, and a connector for connecting the adapter housing and the plug housing. The elastic force of the initial shape acts on the leaf spring at normal temperature and in a heated state, and the leaf spring is deformed in a direction in which the coil spring expands due to a change to a lower temperature side, and a force acts on the ferrule in the axial direction of the ferrule. Depending on the design of the connector, the shape can be stored and used so that the coil spring further extends on the high temperature side.

Although the description has been given of the example of the shape memory alloy, it is not always necessary to use the shape memory alloy, and the shape memory alloy may be used. In addition, the connection module in which the elastic force is generated by such a shape memory member depends on the temperature when assembling the system (generally higher than room temperature) and when it is actually functioning (at room temperature). Temperature when returning) is different. Due to this temperature difference, such a shape memory member changes its shape and, depending on its shape / structure, is incorporated into a structure like the present invention to generate an elastic force. Note that the difference in the temperature difference (the temperature when the system is assembled and the temperature when the system is actually functioning) may be reversed.

FIG. 9 shows an example of a communication system using a long-wavelength band surface emitting semiconductor laser. A ferrule for fixing an optical fiber to a laser module equipped with a laser element chip, an adapter housing for accommodating the ferrule together with the optical fiber, It comprises a device for fixing the optical fiber, a base for integrally fixing the adapter housing, the housing and the laser module. The optical fiber was deflected between the adapter housing and the optical fiber fixing device. The device that fixes the optical fiber uses friction grip compression, and consists of a compression spring made of shape memory alloy and a collar.
1. Collar 1, Collar 1, 2 and split sleeve composed of a ferrule 2 and a split sleeve 2 with a housing arranged between the collars 1 and 2 and a sphere which is in contact with the sphere and a surface in contact with the sphere formed in a conical shape.
An optical fiber is passed through the fitting part of the two ferrules 2. The force that the optical fiber tends to expand due to thermal deformation acts on the left and right, but in the optical fiber fixing device, the ball is pushed to the right by the compression spring and the optical fiber is firmly fixed, so it does not move to the right, The elastic force acts on the side of the adapter housing.

In the example of FIG. 5 described above, the fiber is bent and the fiber is pressed against the laser element by its elastic force. However, the example shown in FIG. The deformation effect generated by the spring made of the shape memory member is superimposed on the force to more effectively press the fiber in the direction of the laser element surface.

FIG. 10 shows a tapered split sleeve, a ferrule for fixing an optical fiber, a coil spring and a collar for applying an axial pressing force to the ferrule, a plug housing for accommodating the split sleeve, the coil spring and the collar, a ferrule and a plug housing. FIG. 2 is a sectional view of two optical connectors each having a connector housing for housing the optical connector and optical connectors having connectors for connecting the adapter housing and the plug housing. The elastic force of the initial shape acts on the coil spring at the normal temperature, changes in the direction in which the coil spring expands due to the temperature change, and acts on the ferrule in the axial direction of the ferrule, whereby the two fibers are effectively connected. Also in this example, a shape memory alloy, a shape memory plastic, or the like can be used as the shape memory member. In the above description, an example in which the shape memory member is used as the spring has been described, but an elastic body such as phosphor bronze or urethane rubber which is a usual spring material may be used. By using such a general-purpose material, a low-cost module can be obtained.

[0085]

(Effect corresponding to Claim 1) The laser oscillation wavelength at which optical fiber communication is expected, such as a computer network or a trunk system for long-distance large-capacity communication, is 1.1.
In the field of the μm band to the 1.7 μm band, there has been no surface emitting semiconductor laser capable of lowering the operating voltage, the oscillation threshold current and the like, generating less heat from the laser element and performing stable oscillation, and a communication system using the same. However, by devising a semiconductor distributed Bragg reflector as in the present invention, the operating voltage, oscillation threshold current, and the like can be reduced, the laser element generates less heat, and stable oscillation can be achieved. The system has been realized. Further, since the optical fiber optically coupled to the light emitting portion of the laser chip of the present invention is mechanically connected with the fiber axis direction being pressed in the direction of the light emitting portion, the laser light emitting portion and the optical fiber are connected to each other. Good optical coupling was obtained, and a highly reliable optical communication system was obtained.

(Effect Corresponding to Claim 2) The laser oscillation wavelength at which optical fiber communication is expected to be 1.1 μm, such as a computer network, a trunk system for long-distance large-capacity communication, is 1.1 μm.
In the field of m band to 1.7 μm band, there is no long wavelength band surface emitting semiconductor laser that can be used stably and a communication system using the same. By using the surface emitting semiconductor laser device chip thus provided, stable oscillation became possible, and a practical optical communication system using this as a light emitting light source was realized. Further, since the optical fiber optically coupled to the light emitting portion of the laser chip of the present invention is mechanically connected with the fiber axis direction being pressed in the direction of the light emitting portion, the laser light emitting portion and the optical fiber are connected to each other. Good optical coupling was obtained, and a highly reliable optical communication system was obtained.

(Effects Corresponding to Claim 3) In such an optical communication system, when two or more optical fibers constituting the optical communication system are optically coupled to each other, the two fiber axes Since the directions were pressed and mechanically connected to each other, good optical coupling between the optical fibers was obtained, and a highly reliable optical communication system was obtained.

(Effect Corresponding to Claim 4) In such an optical communication system, the optical fiber itself is in a pressed state by the elastic force of the optical fiber itself. The structure has resulted in good optical coupling between the optical fibers.

(Effects Corresponding to Claim 5) In such an optical communication system, since the elastic fiber provided in the unit for mechanically connecting the optical fibers is used to be in a pressed state, a simple principle / structure is achieved. As a result, good optical coupling between optical fibers can be obtained.

(Effect Corresponding to Claim 6) In such an optical communication system, a shape memory material is used as an elastic body and assembled at such a temperature that the shape memory material is deformed when assembling such a unit. Subsequent return of the temperature causes the shape memory material to regain the memory shape and generate elastic force, so that a novel optical coupling between the optical fibers can be obtained by a novel principle / structure completely different from the conventional one. It became so.

[Brief description of the drawings]

FIG. 1 is a sectional view of an element part of a long-wavelength band surface emitting semiconductor laser according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a configuration of a semiconductor distributed Bragg reflector of a long wavelength band surface emitting semiconductor laser according to an embodiment of the present invention.

FIG. 3 is a sectional view of an element portion of another configuration of the long-wavelength band surface emitting semiconductor laser according to one embodiment of the present invention.

FIG. 4 is a plan view showing a wafer substrate and a laser element chip on which a long wavelength band surface emitting semiconductor laser element according to one embodiment of the present invention is formed.

FIG. 5 is a cross-sectional view of a long-wavelength band surface emitting semiconductor laser device according to an embodiment of the present invention and an optical coupling device installed with bending.

FIG. 6 is a cross-sectional view of an optical coupling device in which the optical fiber of FIG.

FIG. 7 is a cross-sectional view of an optical coupling device that uses a coil spring elastically deformed by temperature in a device that optically couples with a long wavelength band surface emitting semiconductor laser element according to an embodiment of the present invention.

FIG. 8 is a cross-sectional view of a device for optically coupling with a long wavelength band surface emitting semiconductor laser device according to an embodiment of the present invention, which uses a leaf spring that is elastically deformed by temperature.

FIG. 9 is a cross-sectional view of a long-wavelength band surface emitting semiconductor laser device according to an embodiment of the present invention, an optical coupling device installed with bending, and an optical fiber fixing device utilizing frictional gripping compression.

FIG. 10 is a cross-sectional view of an optical coupling device using a plate spring that elastically deforms with temperature in the optical coupling device.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masayoshi Kato 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Kazuya Miyagaki 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Akira Sakurai 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Atsushi Watada 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Shinji Sato 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Shunichi Sato 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Invention Satoru Sugawara 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Yukie Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Co., Ltd. Ricoh (72) Inventor Takuro Sekiya 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (Reference) 2H037 AA01 BA02 DA04 DA06 DA15 DA16 5F073 AA74 AB17 AB28 BA01 CA05 CB02 DA05 EA15 EA23 FA06

Claims (6)

[The claims] In a laser chip and an optical communication system connected to the laser chip, the laser chip has an oscillation wavelength of 1.1 μm to 1.7 μm, and an active layer for generating light includes a main element of Ga, A surface emitting type having a layer structure of In, N, and As or a layer of Ga, In, and As and having a resonator structure including reflectors provided above and below the active layer to obtain a laser beam. A semiconductor laser element chip, wherein the reflecting mirror is a semiconductor distributed Bragg reflecting mirror that periodically changes a refractive index of a material layer constituting the reflecting mirror to small / large and reflects incident light by light wave interference; The material layer having a small ratio is Al _x Ga _{1 -x} As.
(0 <x ≦ 1) and then, the material layer of the refractive index is large is Al _y
A reflecting mirror having Ga _1-y As (0 ≦ y <x ≦ 1),
And a material layer Al _z Ga _{1 -z} As (0 ≦ y <z) in which the refractive index takes a value between small and large between the material layers with small and large refractive indexes.
<X ≦ 1) is an optical communication system using a surface-emitting type semiconductor laser device chip provided as a light emitting source, wherein an optical fiber optically coupled to a light emitting portion of the laser chip comprises:
An optical communication system, wherein a fiber axis direction is pressed toward the light emitting unit and mechanically connected. 2. In a laser chip and an optical communication system connected to the laser chip, the laser chip has an oscillation wavelength of 1.1 μm to 1.7 μm, and has an active layer for generating light, wherein the main element is Ga, A surface emitting type having a layer structure of In, N, and As or a layer of Ga, In, and As and having a resonator structure including reflectors provided above and below the active layer to obtain a laser beam. A semiconductor laser device chip, wherein the reflecting mirror is a semiconductor distributed Bragg reflecting mirror that periodically changes the refractive index of a material forming the reflecting mirror to small / large and reflects incident light by light wave interference; Is smaller than that of Al _x Ga _{1 -x} As (0 <
x ≦ 1), and the material having a large refractive index is Al _y Ga _1-y A
s (0 ≦ y <x ≦ 1), wherein GaInP or GaInPAs is provided between the active layer and the reflector.
An optical communication system using a surface-emitting type semiconductor laser device chip provided with a non-light-emitting recombination prevention layer comprising a light-emitting source, wherein an optical fiber optically coupled to a light-emitting portion of the laser chip comprises the light-emitting device. An optical communication system characterized in that the fiber axis direction is pressed in the direction of the section and mechanically connected. 3. When two or more optical fibers constituting the optical communication system are optically coupled to each other, the two fiber axes are mechanically connected in a state where both fiber axial directions are pressed to each other. 3. The method according to claim 1, wherein
The optical communication system according to claim 1. 4. The optical communication system according to claim 1, wherein the pressed state is created by an elastic force of the optical fiber itself. 5. The optical communication system according to claim 1, wherein the pressed state is created by an elastic body provided in a unit that mechanically connects the optical fibers. 6. The elastic body is a shape memory material and is assembled at a temperature at which the shape memory material is deformed when assembling the unit. 6. The optical communication system according to claim 5, wherein the optical communication system has a structure in which the elastic force is generated by recovering the elastic force.