JP2002261320A - Optical transmission and receiving system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical transmission and receiving system which operates stably. SOLUTION: Transmission and reception of signals are conducted by a method, where an optical signal outputted from a light emitting section of a laser device is transmitted propagated in space in linear manner, to be received by a light-detecting section of a photo detector, such as a photodiode. Conventionally, the transmission and reception of signals has been conducted by electrical signals using conductor cables, and the problem of the layout and the assembling of the conductor cables becoming complicated has existed. In the optical transmission and receiving system, using a long wavelength band surface emission semiconductor laser whose oscillation wavelength is between 1.1 and 1.7 μm, electrical signals are converted into optical signals, and then the optical signals are transmitted in space, eliminating the conductor cables inside the equipment. Consequently, there is no longer complicated handling necessary for conductor cables in layout, which increases the flexibility in the layout of components, units, or the like inside the equipment and a layout that enables stable operation is realized.

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 a reliability assurance when the optical transmitting / receiving system is incorporated in a device.
In particular, the present invention relates to an optical transmission / reception system using a so-called surface emitting laser that emits light in a direction perpendicular to a semiconductor substrate surface used for manufacturing a semiconductor laser.

[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, in the present situation, in the field of signal transmission / reception which is conventionally performed by a computer network or a conventional conductor, an optical transmission / reception system using an optical fiber is expected to be increased. There is no long-wavelength surface emitting semiconductor laser having a wavelength of up to 1.7 μm and an optical transmitting and receiving system using the same, and the emergence of such a laser is eagerly desired. In recent years, optical transmission / reception systems in premises have been constructed. In view of such a situation, the present inventor has thought that other such optical transmission / reception systems will be introduced and constructed in the near future.

[0010]

SUMMARY OF THE INVENTION The present invention relates to an optical transmission / reception system provided in a device.
It is an object of the present invention to propose a configuration for stably operating the optical transmission / reception system.

A second object is to provide a light emitting light source of such an optical transmitting and receiving system having a laser oscillation wavelength of 1.1 μm.
An object of the present invention is to make it possible to reduce an operating voltage, an oscillation threshold current, and the like when using a long wavelength band surface emitting semiconductor laser of up to 1.7 μm.

A third object is to provide a light emitting source for such an optical transmitting and receiving system having a laser oscillation wavelength of 1.1 μm.
It is an object of the present invention to stably oscillate and use a long-wavelength surface emitting semiconductor laser having a wavelength of m to 1.7 μm.

A fourth object of the present invention is to propose a specific means for solving the problem which occurs when such an optical transmission / reception system is actually incorporated in a device.

A fifth object is also to propose a specific means for solving the problem which occurs when such an optical transmission / reception system is actually incorporated in a device.

A sixth object is to propose a configuration which functions stably when such an optical transmission / reception system is actually incorporated in a device.

A seventh object is to propose a specific configuration for ensuring long-term reliability when such an optical transmission / reception system is actually incorporated in a device.

[0017]

According to the present invention, there is provided an optical transmission / reception system provided inside an apparatus for performing communication inside the apparatus. In the optical transmitting and receiving system provided with a light receiving unit for receiving the optical signal while spatially transmitting, the light emitting element unit and the light receiving element unit of the laser light emitting light source and the light receiving unit respectively cover those elements. A cover member is provided.

Second, the first optical transmission / reception system
Wherein the laser light source has an oscillation wavelength of 1.1 μm.
m to 1.7 μm, and the active layer for generating light is mainly
A layer whose element is Ga, In, N, As, or G
a, In, and As layers to obtain a laser beam
Including reflectors provided above and below the active layer
Surface emitting semiconductor laser device chip with cavity structure
The reflecting mirror has a refractive index of a material layer constituting the reflecting mirror.
Periodically changes to small / large and reflects incident light by light wave interference
Semiconductor distributed Bragg reflecting mirror
The material layer with a small folding ratio is Al_xGa_1-xAs (0 <x ≦ 1)
The material layer having a large refractive index is made of Al_yGa_{1 -y}As (0 ≦
y <x ≦ 1) and the refractive index is small.
Material whose refractive index takes a value between small and large between the material layers of
Material layer Al_zGa_1-zAs (0 ≦ y <z <x ≦ 1)
Surface emitting semiconductor laser device chip
Was.

Thirdly, in the first optical transmission / reception system, the laser light source has an oscillation wavelength of 1.1.
μm to 1.7 μm, and a light-generating active layer is formed of a layer whose main element is Ga, In, N, or As, or
A surface-emitting type semiconductor laser device chip having a resonator structure including a reflector formed of a layer of a, In, and As and provided above and below the active layer for obtaining laser light, The mirror is a semiconductor distributed Bragg reflector in which the refractive index of the material constituting the mirror periodically changes between small and large and reflects incident light by light wave interference. The material having a small refractive index is Al _x Ga _{1−. x} As (0 <x ≦ 1),
The material having a large refractive index is Al _y Ga _{1 -y} As (0 ≦ y <x
.Ltoreq.1), and a surface-emitting type semiconductor laser element chip having a non-radiative recombination preventing layer made of GaInP or GaInPAs between the active layer and the reflective mirror.

Fourth, in the first to third optical transmission / reception systems, the apparatus is a recording apparatus using an electrophotographic principle.

Fifth, in the first to third optical transmission / reception systems, the apparatus is a recording apparatus using the ink jet principle.

Sixth, in the first to fifth optical transmission / reception systems, the cover member is formed of glass.

Seventh, in the first to sixth optical transmission / reception systems, the cover member is detachable.

[0024]

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 with a laser oscillation wavelength of 1.1 μm to 1.7 μm to which the present invention is intended to be applied is realized only with the suggestion of the possibility. The materials for the use, 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).

An undoped lower GaAs spacer layer, 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 n
m) and an undoped upper G layer
The aAs spacer layer is laminated to form a resonator having a thickness of one oscillation wavelength λ (thickness of λ) in the medium.

Furthermore, p-doped C (carbon) is further added.
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, the upper and lower reflectors are formed by alternately laminating a low refractive index layer (a layer having a small refractive index) / a high refractive index layer (a layer having a large refractive index). Between these, the material layer Al _z G whose refractive index takes a value between small and large
a _1-z As (0 ≦ y <z <x ≦ 1) is provided. FIG.
Is a material layer Al _z Ga _{1 -z} As having a refractive index between small and large between a low refractive index layer (a layer with a small refractive index) and a high refractive index layer (a layer with a large refractive index). 1 shows a part of a semiconductor distributed Bragg reflector provided with (0 ≦ y <z <x ≦ 1) (FIG. 1)
Then, the illustration is omitted because the figure becomes complicated).

Conventionally, it has been considered to provide such a material layer for a semiconductor laser having a laser wavelength of 0.85 μm band. However, it is still in the examination stage, and the material and its thickness 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 inventor of the present invention quickly realized 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.

[0033] 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.

Further lasing wavelength, such as such a refractive index takes a value between the small and large material layer _{Al z Ga 1-z As (} 0 ≦ y <z <x ≦ 1) the invention is 1 .1 μm to 1.7 μ
5 nm to 50 nm in the case of a long-wavelength surface emitting semiconductor laser
It is preferable that the thickness is less than 10 nm. If the thickness is smaller than this, there is a problem that the resistance becomes large and the current hardly flows, and the element generates heat and the driving energy becomes high. In addition, when the thickness is large, the resistance becomes small, which is advantageous in terms of heat generation of the element and driving energy, but there is a problem that the reflectance cannot be obtained this time,
As described above, it is necessary to select an optimum range (thickness of 5 nm to 50 nm).

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. In the case of a long-wavelength surface emitting semiconductor laser having a wavelength of 1.7 μm, it is more effective. This is because, for example, in order to obtain the same reflectance (for example, 99.5% or more), the band from 1.1 μm to 1.0 μm is more than 0.85 μm.
In the case of the 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, the operating voltage, the oscillation threshold current, and the like are reduced, and the laser device This is advantageous in terms of preventing heat generation, stable oscillation, and low energy driving.

In other words, 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.

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, Al _x Ga _{1 -x} As (x = 1.0)
(Low refractive index layer to low refractive index layer) and Al _y Ga _1-y As (y
= 0) (in the case of a high refractive index layer-refractive index large layer) 20 period stacking, the reflectance of the semiconductor distributed Bragg reflector is 99.7% or less _{Al z Ga 1-z As (} 0 ≦ y <z
<X ≦ 1) The thickness of the layer is 30 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, when prototypes of 10 nm, 20 nm, and 30 nm which are equivalent to and thinner than this were prototyped, the reflectivity could be kept to a practically acceptable level, and the resistance value of the semiconductor distributed Bragg reflector could be reduced. A 1.3 μm band surface emitting laser device was realized, and laser oscillation was successful. 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, the 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 reflecting mirror and is a part of the upper reflecting mirror, except for the light emitting portion, and is formed on the back surface of the substrate. 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 is used. In the material containing Al (II
The ratio of the low refractive index layer of the lower and upper reflecting mirrors closest to the active layer is G.
It is set to _{a x In 1-x P y} As 1-y (0 <x <1,0 <y ≦ 1) non-radiative recombination preventing layer. Since the carriers are confined between the low-refractive index layers of the upper and lower reflecting mirrors which are closest to the active layer and have a wide gap, only the active region is constituted by a layer containing no Al (the percentage of group III is 1% or less). However, if the low-refractive index layer (wide gap layer) of the reflector in contact with the active region has a structure including Al, when carriers are injected and recombined, non-radiative recombination occurs at this interface, and the luminous efficiency is reduced. Will drop. 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. In many cases, a semiconductor multilayer reflector is 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 contained in the active region and at the interface between the reflector and the active region. Therefore, non-radiative recombination caused by crystal defects caused by Al during carrier injection is eliminated. And non-radiative 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 the crystal defects 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 as described above 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 the present inventor has manufactured, a GaInAs quantum well active layer with a high strain can be grown coherently 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 surface emitting semiconductor laser in a long wavelength band can be formed on a GaAs substrate by using GaInAs having a large In composition and a high compression strain as 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.
In addition, a triple quantum well structure (TQ
Although the example of W) is shown, a structure (SQW, MQW) using a quantum well of another number of wells or the like can 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, as the active layer, a layer whose main element is Ga, In, or As, that is, Ga _x In _{1 -x}
Although an example of As (GaInAs active layer) has been described, in order to perform laser oscillation of a longer wavelength, a layer (GaInNAs active layer) in which N is added and the main element is Ga, In, N, and As is used. Good.

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 studying the composition, a longer wavelength, for example, 1.7
A surface emitting laser in the μm band is also possible.

Further, 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.

In this case as well, as in the case of FIG.
00) is used. N-Al _x Ga _{1 -x} As (x = 0.9) and n-A at a thickness of 1/4 (λ / 4 thickness) of the oscillation wavelength λ in each medium.
n in which l _x Ga _1-x As (x = 0) are alternately stacked for 35 periods
Forming a semiconductor distributed Bragg reflector (Al _0.9 Ga _0.1 As / GaAs lower reflector) on which a λ / 4 thick n-Ga _{x
In 1-x P y As 1} -y (x = 0.5, y = 1) was laminated layer. In this example _{n-Ga x In 1-x} P y As 1-y (x = 0.
5, y = 1) layer is also a part of the lower reflecting mirror 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).

Also in this example, although it is not shown in FIG. 3 because it becomes complicated in FIG. 3, the structure of the semiconductor distributed Bragg reflector has a low refractive index layer (low refractive index layer) as shown in FIG. Layer) and a high refractive index layer (high refractive index layer), a material layer Al _z Ga _1-z having a refractive index between low and high
As (0 ≦ y <z <x ≦ 1) is provided.

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.

[0075] 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 reflecting mirror is removed, and a 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 selectively oxidized layer
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.

When the surface-emitting type semiconductor laser (element) of this example is integrated one-dimensionally or two-dimensionally, the controllability at the time of element production is improved, and the uniformity of the element characteristics of each element in the array is improved. In addition, there is an effect that reproducibility becomes extremely good.

In this example, Ga _x In _{1-x Py} As _1-y (0 <x <1, 0 <y ≦
1) Although the layer is provided on the upper reflecting mirror side, 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 the structure 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 case of the example of FIG. 1 is applied to the lower reflector between the GaAs substrate and the active layer. Of the active layer is suppressed, and crystal growth of the active layer with high quality can be achieved.

Incidentally, such a non-radiative recombination preventing layer is
1 and 3, a part of the semiconductor distributed Bragg reflector is formed, and its thickness is 、 of the oscillation wavelength λ in the medium (thickness of λ / 4). ). Alternatively, a plurality of layers may be provided.

As is apparent 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 with such a configuration, since the polyimide can be easily embedded, the wiring (p-side electrode in this example) is hardly disconnected, and a highly reliable device can be obtained.

The oscillation wavelength of the surface emitting semiconductor laser manufactured in this manner 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, a 1.3 μm band surface emitting semiconductor laser can be realized in the configuration as shown in FIG. 3, as in the case of FIG. Is obtained.

The surface emitting semiconductor laser shown in FIG.
The growth can be performed by the MOCVD method as in the case of the above, but another growth method such as the MBE method can also be used.
Although DMHy is used as a nitrogen source, activated nitrogen and other nitrogen compounds such as NH ₃ can be used.

Further, an example of a 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 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 the optical transmitting / receiving system of the present invention. In this example, an optical signal emitted from the laser element light emitting unit is spatially transmitted, travels straight in the direction of the arrow in the figure, and is received by the optical detector unit of a light receiving element such as a photodiode.

As a laser element that can be suitably used, as described above, a semiconductor distributed Bragg reflecting mirror or a method of providing a non-radiative recombination preventing layer has a laser oscillation wavelength of 1 that could not be realized conventionally. .1 μm band
A 1.7 μm band surface emitting semiconductor laser has
This is preferable in terms of low energy driving and cost reduction in manufacturing.

In the following description, an example in which one laser element is used will be described. However, the 1.1 μm band to 1.7 μm band as in the present invention is used.
Since a large number of laser elements can be easily manufactured at low cost in a long-wavelength surface emitting semiconductor laser on a single chip, a multi-laser array system can be easily realized, and a large amount of information can be exchanged.

FIG. 6 shows another example of the optical transmission / reception system of the present invention. In this example, the optical signal emitted from the laser element light emitting unit is spatially transmitted and travels straight in the direction of the arrow in the figure. Received by the detector unit.

Conventionally, such signal exchange is performed by an electric signal using a conductor cable. Therefore, various electronic devices are connected by an infinite number of conductor cables inside the devices, and the arrangement / processing of the conductor cables is complicated, which has been a problem in the design stage or the assembly stage of a factory.

Therefore, in the present invention, instead of exchanging signals using such a conductor cable, the optical transmission / reception system as shown in FIG. 5 or FIG. Eliminating (or reducing) the number of conductor cables inside the equipment as much as possible, making the inside clearer, eliminating the complexity of processing on the layout of the conductor cables, and free layout of parts / units inside the equipment. The degree was increased.

As the electronic equipment in which the optical transmission / reception system of the present invention is incorporated, for example, a recording apparatus using the electrophotographic principle, such as a copying machine or a laser printer, an ink jet recording apparatus, a recording apparatus for a silver halide photographic process, and the like. Is raised. In addition to these, it can be used for computers, video equipment, television receivers and the like.

FIG. 7 shows an electrophotographic copying machine to which the present invention is suitably applied. FIG. 8 is an enlarged view of the same, showing the interior simply.

The optical transmission / reception system of the present invention is arranged, for example, as shown by a thick arrow in FIG. Here, the optical transmission / reception system as shown in FIG. 6 is simply indicated only by horizontal and vertical thick arrows. A part in the figure is a laser element light emitting part, and B part
The part is a light receiving element part. The reflection member is omitted.

FIG. 9 shows another example to which the present invention is suitably applied, and shows an ink jet recording apparatus. FIG. 10 is an enlarged view of the same, and also shows the inside simply.

The optical transmission / reception system of the present invention is arranged, for example, as shown by a thick arrow in FIG. Here, FIG.
Such an optical transmission / reception system is simply indicated only by a thick horizontal arrow. A part of the figure is a laser element light emitting part, and B part is a light receiving element part.

As described above, according to the present invention, signals are exchanged inside the various electronic devices by eliminating (or reducing) the conductor cables inside the various electronic devices by using the optical transmission / reception system. FIGS. 7 to 10 show an electrophotographic copying machine and an ink jet recording apparatus, respectively, as applicable electronic devices, but are not limited thereto.

However, a recording device using the electrophotographic principle, an ink jet recording device, a recording device of a silver halide photographic process, and the like have a characteristic property that the toner or liquid ink or the liquid developing solution is The device itself is not a very favorable environment for the optical transmitting and receiving system of the present invention because the device itself is dancing alone, together with paper powder, or in the form of a mist.

In consideration of the above, in the present invention, FIG.
As shown in FIG. 1, a cover member for covering the light emitting element portion and the light receiving element portion of each of the laser light emitting light source and the light receiving unit is provided. The covers are formed by a member that transmits light, such as glass. Note that a high-precision plastic member from which internal distortion has been removed may be used instead of glass. Such a cover member has a role of physically or chemically protecting the laser element and the light receiving element of the present invention manufactured by advanced technology.

In addition, foreign substances such as toner, ink and paper dust should not adhere to the optical transmission / reception system of the present invention (the light should be shielded from light to stop functioning). The cover member is detachable and can be immediately removed and cleaned whenever foreign matter adheres. Although the cover is not provided on the reflection member in FIG. 11, it may be provided as needed.

[0110] In view of the above points, the devices that need to be provided with such a cover include the above computers, video devices, television receivers, and the like.
It can be said that the device is a device in which toner powder or paper powder flies by using toner or paper, or a device in which liquid is used inside. It can be said that providing such a cover functions particularly effectively.

[0111]

According to the first aspect of the present invention, an optical transmission / reception system for spatially transmitting an optical signal from a laser light source is provided in the apparatus, so that the internal signal transmission / reception can be performed by the optical transmission / reception system. It became possible to omit the conductor cable used for signal transmission and reception inside the device. Conventionally, the conductor cables used for signal transmission and reception inside the device were complicated, and the layout processing was complicated, but the number of conductor cables used could be reduced, so the complexity was eliminated Not only is it possible, but also the degree of freedom in the layout of each part / unit inside the device has been increased. In addition, since the light emitting element section and the light receiving element section of the laser emission light source and the light receiving unit of this optical transmitting and receiving system are provided with cover members for covering the elements, the light emitting element section and the light receiving element section float inside the apparatus. Damage due to foreign matter or the like can be prevented, and the optical transmission / reception system can operate stably.

[Effects Corresponding to Claim 2] A surface-emitting type semiconductor laser having a laser oscillation wavelength of 1.1 μm to 1.7 μm is used as a laser emission light source of an optical transmission / reception system inside such an apparatus. By devising a semiconductor distributed Bragg reflector for this surface emitting semiconductor laser, the operating voltage, oscillation threshold current, etc. can be reduced, the laser element generates less heat, and stable oscillation can be achieved. It could be a transmission / reception system.

[Effects Corresponding to Claim 3] A surface emitting semiconductor laser having a laser oscillation wavelength of 1.1 μm band to 1.7 μm band is used as a laser emission light source of an optical transmission / reception system inside such an apparatus. Since a non-radiative recombination preventing layer is provided between the active layer of the surface-emitting type semiconductor laser and the reflecting mirror, stable oscillation and use can be achieved, and a practical optical transmission / reception system can be obtained. Was.

[Effects Corresponding to Claim 4] By providing such an optical transmission / reception system in a recording apparatus using the electrophotographic principle, it is possible to omit a conductor cable used for signal transmission and reception inside the apparatus. became. Further, in such a recording apparatus, toner and paper dust are constantly flying inside the apparatus, which has an adverse effect on the light emitting element section and the light receiving element section of the optical transmitting and receiving system. Since the member is provided, such an adverse effect can be prevented, and the optical transmission / reception system can operate stably.

[Effects Corresponding to Claim 5] By providing such an optical transmission / reception system in a recording apparatus using the ink jet principle, it is possible to omit a conductor cable used for signal transmission and reception inside the apparatus. Was. Also,
In such a recording apparatus, liquid ink, its mist, paper dust, and the like are constantly flying inside the apparatus, and adversely affect the light emitting element portion and the light receiving element portion of the optical transmission / reception system (particularly when the liquid ink adheres). However, in the present invention, a cover member for covering those elements is provided, so that such an adverse effect can be prevented, and the optical transmission / reception system can operate stably.

[Effects Corresponding to Claim 6] Since the cover member for covering the light emitting element portion and the light receiving element portion of such an optical transmission / reception system is made of glass, it can be manufactured at low cost and does not hinder light transmission. The optical transmission / reception system functioning as described above.

[Effects Corresponding to Claim 7] Since a cover member for covering the light emitting element portion and the light receiving element portion of such an optical transmission / reception system is made detachable, toner,
Even if foreign matter such as ink or paper dust adheres, it can be easily removed, cleaned, and reinstalled, so that a long-term highly reliable optical transmission and reception system that functions well for a long time can be obtained.

[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 a long-wavelength band surface emitting semiconductor laser according to an 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 conceptual diagram showing an example of the optical transmission / reception system of the present invention.

FIG. 6 is a conceptual diagram showing another example of the optical transmission / reception system of the present invention.

FIG. 7 is an example of an electrophotographic copying machine to which the present invention is suitably applied.

FIG. 8 is an example of an electrophotographic copying machine incorporating the optical transmission / reception system of the present invention.

FIG. 9 is an example of an ink jet recording apparatus to which the present invention is suitably applied.

FIG. 10 is an example of an ink jet recording apparatus incorporating the optical transmission / reception system of the present invention.

FIG. 11 is a conceptual diagram showing still another example of the optical transmission / reception system of the present invention.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Teruyuki Furuta 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 Ken Kanai 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 Shunichi Sato 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Yukie Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Invention Satoru Sugawara 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Shuichi Hikichi 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh (72) Inventor Shinji Sato 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (Reference) 2C061 AQ05 AQ06 BB08 CG15 2H027 JA03 JB30 JC20 ZA09 5F073 AA22 AA74 AB17 BA07 BA09 CA07 CA17 DA05 5F89 AA10

Claims (7)

[Claims] 1. An optical transmission / reception system provided inside an apparatus for performing communication inside the apparatus, wherein a light receiving unit for spatially transmitting an optical signal of a laser light source and receiving the optical signal is provided. In the optical transmitting and receiving system, the light emitting and receiving unit of each of the laser light emitting light source and the light receiving unit is provided with a cover member that covers those elements. 2. The laser light source according to claim 1, wherein said laser light source has an oscillation wavelength of 1.
1 μm to 1.7 μm, wherein the active layer that generates light is a layer whose main element is made of Ga, In, N, As or a layer made of Ga, In, As, and the active layer is used to obtain a laser beam. A surface-emitting type semiconductor laser device chip having a resonator structure including a reflector provided on an upper portion and a lower portion of the surface mirror, wherein the reflector has a material layer constituting the reflector periodically having a refractive index of small / large. A semiconductor distributed Bragg reflector that changes and reflects incident light by light wave interference, and the material layer having a small refractive index is Al _x Ga _{1 -x} As (0 <x ≦ 1).
And the material layer having a large refractive index is Al _y Ga _1-y As (0
≦ y <x ≦ 1), and a material layer Al _z Ga _1-z As having a refractive index between a small and a large value between the material layers having a small and a large refractive index. 2. The optical transmitting / receiving system according to claim 1, wherein the optical transmitting / receiving system is a surface-emitting type semiconductor laser device chip provided with (0 ≦ y <z <x ≦ 1). 3. The laser light source has an oscillation wavelength of 1.
1 μm to 1.7 μm, wherein the active layer that generates light is a layer whose main element is made of Ga, In, N, As or a layer made of Ga, In, As, and the active layer is used to obtain a laser beam. A surface-emitting type semiconductor laser device chip having a resonator structure including a reflecting mirror provided at an upper portion and a lower portion of the reflecting mirror, wherein the refractive index of a material constituting the reflecting mirror changes periodically between small and large. A semiconductor distributed Bragg reflector that reflects incident light by light wave interference, wherein the material having a small refractive index is Al _x Ga _{1 -x} As (0 <x ≦ 1), and the material having a large refractive index is Al _y Ga _1-y As (0 ≦ y
<X ≦ 1), characterized in that it is a surface-emitting type semiconductor laser device chip provided with a non-radiative recombination prevention layer made of GaInP or GaInPAs between the active layer and the reflector. The optical transmission and reception system according to claim 1. 4. The optical transmission / reception system according to claim 1, wherein the device is a recording device using an electrophotographic principle. 5. The optical transmission / reception system according to claim 1, wherein the apparatus is a recording apparatus using an ink-jet principle. 6. The optical transmission / reception system according to claim 1, wherein the cover member is formed of glass. 7. The optical transmitting and receiving system according to claim 1, wherein the cover member is detachable.