JP2002299760A - Air vehicle and optical communication system therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical communication system for an air vehicle, using a light source which has superior temperature characteristics, and which stably operates at a low power. SOLUTION: The optical communication system for the air vehicle comprises a communication equipment 11 connected to communications equipment 15 via an optical fiber 19. Here, the equipment 11 is provided corresponding to an apparatus 12 and has a signal control circuit 13 and a surface-emitting semiconductor laser/photodetector (14). The equipment 15 is provided corresponding to an apparatus 16 and has a signal control circuit 17 and a surface-emitting semiconductor laser/photodetector (18). As the surface-emitting semiconductor lasers of the laser/photodetectors (14), (18), long wavelength band surface- emitting semiconductor lasers are used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an airplane (aircraft).
TECHNICAL FIELD The present invention relates to an optical communication system for an air vehicle and an air vehicle used for an air vehicle such as a spacecraft and a spacecraft.

[0002]

2. Description of the Related Art Conventionally, a surface-emitting type 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 ( (Approximately 10 degrees), which facilitates coupling with an optical fiber and further facilitates inspection of an element. For this reason, attention has been paid particularly to elements suitable for configuring an optical transmission module (optical interconnection device) of the parallel transmission type.

In general, a surface emitting semiconductor laser is made of GaAs.
An optical resonator comprising an active layer made of s or GaInAs, an upper reflector disposed above the active layer, and a lower reflector disposed below the active layer (substrate side) is provided. Since the length of the optical resonator is extremely short as compared with the case of the light emitting semiconductor laser, it is necessary to make the laser oscillation easy by setting the reflectance of the reflecting mirror to an extremely high value (99% or more). For this reason, a semiconductor distributed Bragg 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 is usually used for the upper reflecting mirror and the lower reflecting mirror. A reflector (DBR) is used.

By the way, a long-wavelength laser having an oscillation wavelength of 1.1 μm or more, for example, an oscillation wavelength of 1.3 μm or 1.5 μm.
In order to realize a long wavelength band laser that is 5 μm band,
Conventionally, InP is used for the substrate, and InGa is used for the active layer.
AsP is used. In this case, In
The lattice constant of P is large, and a large difference in the refractive index cannot be obtained with a reflecting mirror material matching the lattice constant.
There is a problem that it is necessary to set 0 or more pairs. Also, I
The semiconductor laser formed on the nP substrate also has a problem that the characteristics greatly change depending on the temperature.
It is necessary to use a device for keeping the temperature constant.
Due to the problems of the number of layers and temperature characteristics, InP
And a long wavelength surface emitting semiconductor laser using InGaAsP for the active layer has not been put to practical use.

On the other hand, Japanese Patent Application Laid-Open No. 9-237942 discloses that a GaAs substrate is used as a substrate, and at least one of a lower semiconductor distributed Bragg reflector and an upper semiconductor distributed Bragg reflector has a low refractive index. As a layer, a semiconductor layer made of AlInP that can be lattice-matched with a GaAs substrate is used.
A surface-emitting type semiconductor laser using a semiconductor layer made of s to obtain a refractive index difference larger than that of the prior art and realizing a semiconductor distributed Bragg reflector having a high reflectance with a small number of layers is disclosed. .

In the above-mentioned surface emitting semiconductor laser, G
aInNAs is used as a material for the active layer. This is because the band gap (forbidden band width) can be reduced from 1.4 eV to 0 eV by increasing the N composition, and therefore, it can be used as a material that emits a wavelength longer than 0.85 μm. Because it becomes. In addition, since lattice matching with the GaAs substrate is possible, G
A semiconductor layer made of aInNAs is preferable as a material for a long-wavelength surface emitting semiconductor laser in a 1.3 μm band and a 1.55 μm band.

However, conventionally, only the possibility of a surface emitting semiconductor laser having a wavelength band longer than 0.85 μm has been suggested, and such a device has not been realized in practice.

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 is used. GaAs is used for the low refractive index layer of the semiconductor distributed Bragg reflector as disclosed in Japanese Unexamined Patent Publication (Kokai) No. 9-237942.
In the case of using a semiconductor layer made of AlInP that can be lattice-matched to the substrate, the laser element did not emit light at all, or even if it emitted light, its emission efficiency was low, far from a practical level. This is because a material containing Al is chemically very active and crystal defects caused by Al are likely to occur. In order to solve this problem, Japanese Patent Application Laid-Open Nos. 8-340146 and 7-307525 propose that a semiconductor distributed Bragg reflector is formed from GaInNP and GaAs that do not contain Al. 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 becomes very large, making fabrication difficult.

That is, at present, optical fiber communication is expected in computer networks and the like.
The laser wavelength that can be used for it is 1.1 μm to 1.7 μm
There is no long-wavelength band surface emitting semiconductor laser and an optical communication system using the same, and realization of the realization is eagerly desired.

[0010]

In particular, in recent years, many electric and electronic devices have been mounted on the body of a flying body such as an airplane (aircraft) or a spacecraft, and advanced control has been performed. As a result, the number of wires between devices has become enormous,
In addition, high-speed, large-capacity data transmission is required between many devices. As described above, when a large number of electrical and electronic devices are mounted on a flying body, the weight of the aircraft also increases,
It takes a lot of time to take measures against electromagnetic noise. Therefore, application of optical wiring using an optical fiber for connection between devices has been studied.

Since the optical wiring is not affected by electromagnetic noise, the design of the airframe is facilitated, and the design change and repair are also facilitated. In addition, since optical wiring can transmit signals over a long distance at a higher speed than electric wiring, large-capacity information can be transmitted between devices with high reliability. Further, since the transmission speed and transmission distance of optical wiring are much larger than those of electric wiring, time division multiplex transmission in which signals transmitted using a large number of electric wirings are collectively transmitted by a small number of optical wirings can be performed. . Therefore, the number of wires can be reduced, and the weight of the machine can be reduced.

However, for the following reasons, the application of the optical wiring to the communication system in the body of a flying body such as an airplane (aircraft) or a spacecraft is limited. That is, as a transmission medium in an optical communication system for a flying object such as an airplane (aircraft) or a spacecraft, a quartz-based fiber is desirable because it can be transmitted at high speed and long distance and has heat resistance. In this fiber, the wavelength band where the transmission loss is small is 1.3 μm band and 1.
5 μm band. Conventionally, the light emitting element in this wavelength band is InP
GaInAsP-based Fabry-Perot (FP) on substrate
Type, distributed feedback (DFB) type, distributed Bragg reflector (DB
R) type laser elements are used. However, as described above, the light emitting characteristics of this material-based device greatly change as the environmental temperature changes. For this reason, when used as a light source for optical wiring of a flying object such as an airplane (aircraft) or a spaceship having a large fluctuation in environmental temperature, it is necessary to add a temperature control device such as a Peltier element or a heater to the light emitting element portion. In addition, it is necessary to add a power supply or a battery for operating the temperature control devices. For this reason, the weight of the aircraft increases. This is a major obstacle to the introduction of optical wiring for airplanes (airplanes) and spacecraft, for which weight reduction is one of the most important issues.

For the above reasons, especially in an optical communication system for air vehicles such as airplanes (aircraft) and spacecraft,
There is a demand for a light source that has excellent temperature characteristics and operates stably with low power.

An object of the present invention is to provide an optical communication system for a flying object and a flying object that use a light source having excellent temperature characteristics and operating stably with low power.

[0015]

In order to achieve the above object, according to the first aspect of the present invention, there is provided an active layer, an upper mirror provided above the active layer, and a lower mirror provided below the active layer. A surface-emitting type semiconductor laser having at least a lower reflector as a resonator is used as a light source, the devices are connected by an optical fiber, and optical communication is performed between the devices by an optical signal from the light source. In an optical communication system for air vehicles, the surface emitting type semiconductor laser has an oscillation wavelength of 1.1 μm to 1.7 μm, and the active layer includes a layer whose main element is Ga, In, N, As.
Alternatively, a layer whose main element is Ga, In, or As is used, and the upper reflector and / or the lower reflector are formed by periodically stacking a material layer having a small refractive index and a material layer having a large refractive index. In the semiconductor distributed Bragg reflector, 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), between the material layer having a small refractive index and the material layer having a large refractive index, Al _z Ga is used as a material layer having a value between a small refractive index and a large refractive index. _1-z As (0 ≦ y <
z <x ≦ 1) layer is provided.

According to a second aspect of the present invention, there is provided a surface emitting device having at least a resonator having an active layer, an upper reflector provided above the active layer, and a lower reflector provided below the active layer. Type semiconductor laser is used as a light source,
In an optical communication system for an air vehicle in which devices are connected by an optical fiber and optical communication is performed between the devices by an optical signal from the light source, the surface emitting semiconductor laser has an oscillation wavelength of 1 .1 .mu.m to 1.7 .mu.m, and the main element in the active layer is Ga, In, N, As.
Or a layer mainly composed of Ga, In, As
Wherein the upper reflector and / or the lower reflector are semiconductor distributed Bragg reflectors in which a material layer having a small refractive index and a material layer having a large refractive index are periodically laminated, The material layer having a small refractive index is Al _x Ga _1-x
As (0 <x ≦ 1), the material layer having a large refractive index is A
l _y Ga _1-y are As (0 ≦ y <x ≦ 1), between the active layer and the upper reflector and / or the lower reflector is made of GaInP or GaInPAs nonradiative recombination prevention layer Is provided.

According to a third aspect of the present invention, there is provided an optical communication system for an air vehicle according to the first or second aspect,
The optical fiber is a silica-based single mode fiber.

According to a fourth aspect of the present invention, there is provided an optical communication system for an air vehicle according to the first or second aspect,
The optical communication between the devices is characterized in that a parallel transmission system using a plurality of optical fibers is used.

According to a fifth aspect of the present invention, there is provided an optical communication system for a flying object according to the first or second aspect,
The optical communication between the devices is characterized in that a multi-wavelength transmission system for simultaneously transmitting a plurality of optical signals having different wavelengths in one optical fiber is used.

According to a sixth aspect of the present invention, there is provided a flying object equipped with the optical communication system for a flying object according to any one of the first to fifth aspects.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. The optical communication system for an airplane according to the present invention uses a long-wavelength surface emitting semiconductor laser having a laser oscillation wavelength of 1.1 μm to 1.7 μm with a small transmission loss as a light emitting light source.

Such a surface emitting semiconductor laser is newly devised by the present inventor.

That is, as described above, a long-wavelength surface emitting semiconductor laser having a laser oscillation wavelength of 1.1 μm to 1.7 μm has not been realized because there is only a suggestion of the possibility. The inventor of the present application has proposed that Ga is used as an active layer.
The laser oscillation wavelength is set to 1.1 using a material such as InNAs.
A long-wavelength surface emitting semiconductor laser having a wavelength of from μm to 1.7 μm was realized.

FIGS. 1 (a) and 1 (b) show light for a flying object according to the present invention.
Configuration of surface emitting semiconductor laser used for communication system
It is a figure showing an example. FIG. 1 (b) is an activity of FIG. 1 (a).
It is an enlarged view of the part of an active layer. See FIGS. 1 (a) and 1 (b)
Then, this surface emitting semiconductor laser has a laser oscillation wavelength
Has a long wavelength band surface emitting semiconductor laser of 1.1 μm to 1.7 μm.
N-GaAs substrate 1 having a plane orientation of (100)
01, 1/1 of the oscillation wavelength λ in each medium.
N-Al with 4 times the thickness (thickness of λ / 4)_xGa_{1 -x}As
(X = 1.0) (low-refractive-index layer, that is, low refractive index
Layer) and n-Al_yGa_1-yAs (y = 0) (high refractive index layer,
That is, n in which 35 layers are alternately laminated with a layer having a large refractive index).
-Semiconductor distributed Bragg reflectors (AlAs / GaAs lower part)
A semiconductor distributed Bragg reflector 102 is formed, and
N-Ga having a thickness of λ / 4_xIn_{1 -x}P_yAs_1-y(X =
0.5, y = 1) The layer 103 is laminated. In this example
Is n-Ga_xIn_1-xP_yAs_1-y(X = 0.5, y =
1) The layer 103 is also a part of the lower reflector 104 and has a low refractive index
(A layer having a small refractive index).

On the lower reflector 104, an undoped lower GaAs spacer layer 105 and three layers of Ga _x I
Active layer as n _1-x As quantum well layer (quantum well active layer)
106a and GaAs barrier layer 106b (20 nm thick)
Are stacked and an undoped upper GaAs spacer layer 107 is laminated to form a resonator having a thickness of one oscillation wavelength λ (thickness of λ) in the medium.

On the resonator, a C (carbon) -doped p-Ga _x In _{1 -x Py} As _{1 -y} (x = 0.5, y = 1) layer 108 and a Zn-doped p-Al _x Ga _{1 -x} As (x = 0) is alternately laminated with a thickness of １ ／ of the oscillation wavelength λ in each medium to form a periodic structure (one period), on which C-doped p is formed. -Al _x Ga _1-x As (x = 0.9) and Zn-doped p-Al _x Ga _1-x As (x = 0) in each medium at a thickness of １ ／ times the oscillation wavelength λ. A semiconductor distributed Bragg reflector (Al _0.9 Ga _0.1 As / GaAs upper semiconductor distributed Bragg reflector) 109 having an alternately laminated periodic structure (25 periods) is formed. In this _{example, p-Ga x In 1-} x P y As 1-y (x =
0.5, y = 1) The layer 108 is also a part of the upper reflecting mirror 109 and is a low refractive index layer (a layer having a small refractive index).

Here, both the upper and lower reflecting mirrors 104 and 109 are formed by alternately laminating a low refractive index layer (a layer having a small refractive index) and a high refractive index layer (a layer having a large refractive index). In the present invention, a value between a small refractive index and a large refractive index is provided between a low refractive index layer (a layer having a small refractive index) and a high refractive index layer (a layer having a large refractive index). Material layer Al _z Ga _{1 -z} As (0 ≦
y <z <x ≦ 1).

FIG. 2 shows a material having a refractive index between a low refractive index and a high refractive index between a low refractive index layer (a layer having a low refractive index) and a high refractive index layer (a layer having a high refractive index). Layer Al _z Ga _{1 -z} As (0 ≦ y <z
FIG. 2 is a diagram illustrating a part of a semiconductor distributed Bragg reflector provided with <x ≦ 1 (in FIG. 1, illustration of a material layer whose refractive index takes a value between small and large is omitted. There).

The provision of a material layer having a refractive index between a small value and a large value can be achieved by providing a laser oscillation wavelength of 1.1 μm to 1.7 μm.
No studies have been made on long-wavelength surface emitting semiconductor lasers. The inventor of the present application has immediately 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), and is keen to realize it. Study was carried out.

The material layer whose refractive index takes a value between low and high is
By controlling the gas flow rate during formation,
It is formed such that the refractive index of the material layer is changed continuously or stepwise by changing the composition continuously or stepwise.

More specifically, Al _z Ga _{1 -z} As (0 ≦
y <z <x ≦ 1) The layer is formed such 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 produced by controlling the gas flow rate during layer formation, as described above. Also, A
The same effect can be obtained by changing the ratio between 1 and Ga continuously as described above, or by changing the ratio stepwise.

The reason for providing a material layer having a refractive index between a small value and a large value is that the p-semiconductor distributed Bragg reflector, which is one of the problems of the distributed Bragg reflector, has a high electric resistance. It is to solve. This is due to a hetero-barrier generated at the interface between the two types of semiconductor layers constituting the semiconductor distributed Bragg reflector. However, by providing a material layer having a refractive index between a small value and a large value, a low refractive index layer and a high refractive index layer are provided. By making the Al composition change gradually from one composition to the other at the interface of the refractive index layer and changing the refractive index, it becomes possible to suppress the generation of the hetero barrier.

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)
In the case of a long-wavelength surface emitting semiconductor laser having a laser oscillation wavelength of 1.1 μm to 1.7 μm, it is preferable to set the thickness to 5 nm to 50 nm. There are disadvantages that the element generates heat and the driving energy increases. On the other hand, if the thickness is more than 50 nm, the resistance becomes small, which is advantageous in terms of heat generation of the element and driving energy. However, there is a problem that a large reflectivity cannot be obtained this time, so that the thickness is in the range of 5 nm to 50 nm. There is a need.

The provision of such a material layer (a material layer having a refractive index between a small value and a large value) is necessary for a long-wavelength surface emitting semiconductor laser having a laser oscillation wavelength of 1.1 μm to 1.7 μm. Especially effective. Because, for example, to obtain the same reflectance (for example, 99.5% or more),
For example, 1.1 μm to 1.7 μm rather than 0.85 μm
In the case of a 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.

That is, such a material layer (a material layer having a refractive index between a small value and a large value) is used for a semiconductor distributed Bragg reflector.
Means that the laser oscillation wavelength is 1.1 μm to 1.7 μm.
This is particularly effective in the case of a long-wavelength surface emitting semiconductor laser of μm.

As an example of a more detailed examination result for obtaining an effective reflectance, for example, in a 1.3 μm band surface emitting semiconductor laser, Al _x Ga _{1 -x} As (x = 1.
0) (low refractive index layer, that is, a layer having a low refractive index) and Al _y
In the case where Ga _1-y As (y = 0) (high refractive index layer, that is, a layer having a large refractive index) is laminated for 20 periods, the reflectivity of the semiconductor distributed Bragg reflector becomes 99.7% or less.
The thickness of the l _z Ga _{1 -z} As (0 ≦ y <z <x ≦ 1) 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, 10 nm, 20 nm, 30
As a result, a 1.3 μm band surface emitting laser device that can maintain the reflectance at a level that does not cause a practical problem and reduce the resistance value of the semiconductor distributed Bragg reflector can be realized. And succeeded in laser oscillation. Other configurations of the prototyped laser element are as described below.

In the multilayer reflector, there is a band having a high reflectance including the design wavelength (assuming that the film thickness can be completely controlled). This band is called the high-reflectance band (including the region where the reflectivity is higher than the required value for the target wavelength). The reflectivity at the design wavelength is the highest, and decreases slightly as the wavelength increases. Area. This 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. However, since a film thickness error of about ± 1% actually occurs, the target wavelength deviates from the wavelength having the highest reflectance. For example, when the target wavelength is 1.3 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 high reflectivity (a region where the reflectivity 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, the laser oscillation wavelength is 1.1 μm
In a long wavelength band surface emitting semiconductor laser of ~ 1.7 μm,
By devising the configuration of such a semiconductor distributed Bragg reflector,
By optimizing, it is possible to reduce the resistance value while keeping the reflectance high, so that the operating voltage, the oscillation threshold current, etc. can be reduced, and the prevention of heat generation of the laser element, stable oscillation, and low energy driving can be achieved. .

Referring again to FIG. 1, the top, pA
The l _x Ga _1-x As (x = 0) layer 110 is a p-side electrode 112
It also has a function as a contact layer (p-contact layer) for making contact with the substrate.

In the example shown in FIG. 1, a portion outside the current path is irradiated with protons (H ⁺ ) to form an insulating layer (high resistance portion) 11.
1, the current narrowing portion is formed.

In the example shown in FIG.
The p-side electrode 112 is formed on the p-contact layer 110, which is the uppermost layer of the substrate 101, except for the light emitting portion 114, and the n-side electrode 113 is formed on the back surface of the substrate 101.

Thus, the surface emitting semiconductor laser shown in FIG. 1 is formed.

In the surface-emitting type semiconductor laser shown in FIG. 1, specifically, the In composition x of the quantum well active layer 106 is 39%.
(Ga0.61In0.39As). The thickness of the quantum well active layer 106 was 7 nm. The quantum well active layer 106 had a compressive strain of about 2.8% with respect to the GaAs substrate.

The whole surface emitting semiconductor laser shown in FIG. 1 was grown by MOCVD. In this case, no lattice relaxation was observed. The material constituting the layers of the semiconductor laser, TMA (trimethyl aluminum), TMG (trimethyl gallium), TMI (trimethyl indium), AsH ₃ (arsine) were used PH ₃ a (phosphine). H ₂ was used as a carrier gas. When the strain is large as in the active layer (quantum well active layer) 106 of the surface emitting semiconductor laser shown in FIG. Here, the GaInAs layer (quantum well active layer) 106 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 the example of FIG. 1, the upper and lower reflectors 104,
Activity between carrier injection and recombination between 109
Region (upper spacer layer 107, lower spacer layer 105
Resonator composed of the multiple quantum well active layer 106)
In the active region, a material containing Al (occupied in group III)
(The ratio is 1% or more).
4, the most active layer 106 of the low refractive index layer of the upper reflecting mirror 109
Layer close to Ga_xIn_1-xP _yAs_1-y(0 <x <1,0 <
y ≦ 1) non-radiative recombination preventing layers 103 and 108
You. The carrier has a wide gap closest to the active layer 106.
Low refraction of the upper reflecting mirror 109 and the lower reflecting mirror 104
Confined between the active layers, only the active region contains Al.
Layer (less than 1% of group III)
Also, the low refractive index of the reflecting mirrors 109 and 104 in contact with the active region
Layer (wide gap layer) containing Al
Are not emitted at this interface when carriers are injected and recombine.
Light recombination occurs and the luminous efficiency decreases. Therefore, non
The light-emitting recombination preventing layers 103 and 108 are layers containing no Al.
It is desirable to configure.

The Ga _x In _{1-x Py} As _1-y (0 <
x <1, 0 <y ≦ 1) Non-radiative recombination preventing layer 1 composed of layers
Nos. 03 and 108 have a smaller lattice constant than the GaAs substrate and have a tensile strain.

In the epitaxial growth, since the growth is performed by reflecting the information of the base, 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 defect reaches 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 103 and 108 is also has the role of carrier confinement and the active region in contact with the active _{region, Ga x In 1-x P} y As 1-y (0 <x <1 , 0 <y ≦
1) As the lattice constant of the layers 103 and 108 decreases, the band gap energy can be increased. For example, Ga _x
In the case of In _1-x P (when y = 1), x increases and G
As approaching aP, the lattice constant increases and the band gap increases. The band gap Eg is Eg by direct transition.
(Γ) = 1.351 + 0.643x + 0.786x ² ,
Indirect transition gives Eg (X) = 2.24 + 0.02x. Therefore, the active region and Ga _x In _{1-x Py} As _1-y
(0 <x <1, 0 <y ≦ 1) Since the hetero barriers of the layers 103 and 108 are large, carrier confinement is good, and there are effects such as reduction in threshold current and improvement in temperature characteristics.

Further, the Ga _x In _{1-x Py} As _1-y (0
<X <1, 0 <y ≦ 1) The non-radiative recombination prevention layers 103 and 108 have a larger lattice constant than the GaAs substrate, have a compressive strain, and have a lattice constant of the active layer 106. The constant is Ga _x In _{1-x Py} As _1-y (0 <x <1,
0 <y ≦ 1) The layers 103 and 108 have a larger compressive strain.

The Ga _x In _{1-x Py} As _1-y (0 <
(x <1, 0 <y ≦ 1) Since the directions of strain of the layers 103 and 108 are the same as the direction of the active layer 106, the layers 103 and 108 work to reduce the substantial amount of compressive strain felt by the active layer 106. The larger the strain, the more easily affected by external factors. Therefore, it is particularly effective when the amount of compressive strain of the active layer 106 is large, for example, 2% or more, or when it exceeds the critical film thickness.

For example, a surface emitting semiconductor laser having an oscillation wavelength of 1.3 μm is preferably formed on a GaAs substrate, and a semiconductor multilayer mirror is often used as a resonator, and the total thickness is 5 to 8 μm. Therefore, it is necessary to grow 50 to 80 semiconductor layers before growing the active layer. (On the other hand, in the case of the edge emitting laser, the total thickness before growing the active layer is 2
It is only necessary to grow about three semiconductor layers of about μm. In this case, even if a high-quality GaAs substrate is used, defects on the surface of the GaAs substrate are caused by various causes (defects once generated basically crawl in the crystal growth direction and defects are generated at a hetero interface). The defect density on the surface immediately before the growth of the active layer is inevitably higher than the density. 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 the example shown in FIG. 1, since the Al is not contained in the active region and at the interface between the reflector and the active region, non-radiative recombination caused by crystal defects caused by Al at the time of carrier injection. Disappeared and non-radiative recombination was reduced.

As described above, the configuration in which the interface between the reflecting mirror and the active region does not contain Al, that is, the provision of the non-radiative recombination preventing layers 103 and 108, means that the upper and lower reflecting mirrors 1 are used.
Although it is preferable to apply both to the mirrors 09 and 104, it is effective to apply the mirror to only one of the reflecting mirrors. In the example of FIG. 1, both the upper and lower reflecting mirrors are semiconductor distributed Bragg reflecting mirrors 10.
9, 104, one of the reflectors may be a semiconductor distributed Bragg reflector and the other may be a dielectric reflector. Further, in the example of FIG. 1, only the layer closest to the active layer of the low refractive index layer of the reflection mirror _{Ga x In 1-x P y} As 1-y (0 <x <
1,0 <y ≦ 1) as a non-radiative recombination preventing layer,
Ga _x In _{1-x Py} As _1-y (0 <x <1, 0 <y
<1) may be used as a non-radiative recombination preventing layer.

Further, in the example of FIG.
By applying this idea to the lower reflector 104 between the first active layer 106 and the active layer 106, it is possible to suppress the adverse effect of crystal defects caused by Al on the active layer, which is a problem when growing the active layer 106. Accordingly, crystal growth of the active layer 106 with high quality can be achieved. As a result, a surface emitting 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 are provided, the above effect can be obtained without particularly increasing the number of stacked reflectors.

The oscillation wavelength of the surface emitting semiconductor laser fabricated 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 created by the inventor of the present application, 600
A high strain GaInAs quantum well active layer can be grown coherently thicker than before by a growth method with a high degree of non-equilibrium, such as low-temperature growth at a temperature of less than or equal to ℃.
m. 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 is clear 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 high 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 106, a structure (SQW, MQW) using quantum wells 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. Although an example in which GaAs is used as the semiconductor substrate 101 has been described, the above concept can be applied even when another semiconductor substrate such as InP is used. Further, the cycle of the reflecting mirrors 104 and 109 is not limited to the above-described example, and may be another cycle.

In the above-described example, the active layer 106 is an example in which the main element is a layer composed of Ga, In, and As, that is, Ga _x In _{1 -x} As (GaInAs active layer). In order to carry out the laser oscillation, the active layer 106 is formed by adding N and adding Ga, In, N, A
s (GaInNAs active layer).

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, even if GaAsSb is used for the active layer 106, a 1.3 μm band surface emitting laser can be realized on the GaAs substrate 101. Thus, the wavelength of 1.1 μm to 1.7 μm
Although the conventional semiconductor laser has no suitable material, the active layer 106 has high strain GaInAs, GaInNAs, and GaInAs.
Non-radiative recombination preventing layers 103, 1 using AsSb
In the long wavelength region of the wavelength range of 1.1 μm to 1.7 μm where stable oscillation has conventionally been difficult,
High-performance surface-emitting semiconductor lasers can now be realized.

FIGS. 3A and 3B are diagrams showing another example of the configuration of the long-wavelength band surface emitting semiconductor laser used in the optical communication system for air vehicles according to the present invention. Note that FIG.
FIG. 3B is an enlarged view of an active layer portion of FIG.

The surface emitting semiconductor lasers of FIGS. 3A and 3B also use the n-GaAs substrate 201 having a plane orientation of (100) similarly to the surface emitting semiconductor lasers of FIGS. 1A and 1B. I'm using Then, on this substrate 201, n-Al _x Ga _{1 -x} As (x = 0.9) with a thickness (thickness of λ / 4) of 発 振 of the oscillation wavelength λ in each medium. n-Al
_x− Ga _1−x As (x = 0) is alternately stacked for 35 periods.
Semiconductor distributed Bragg reflector (Al _0.9 Ga _0.1 As / Ga
As lower reflector) 202 is formed, thereon in the thickness of _{λ / 4 n-Ga x In} 1-x P y As 1-y (x = 0.5, y =
1) A layer (non-radiative recombination preventing layer) 203 is formed. In this _{example, n-Ga x In 1-} x P y As 1-y (x =
0.5, y = 1) The layer 203 is also a part of the lower reflecting mirror 204 and is a low refractive index layer.

The undoped lower GaAs spacer layer 205 and the three Ga _x I
_{n 1-x N y As 1} -y quantum well layer in which the active layer (quantum well active layer) 206a and a GaAs barrier layer 206 b (thickness of 15
nm), a triple quantum well (TQW) in this example, and an undoped upper G
The aAs spacer layer 207 is laminated to form a resonator having a thickness (λ thickness) of one oscillation wavelength in the medium.

A p-semiconductor distributed Bragg reflector (upper reflector) 209 is formed on the resonator.

The upper reflecting mirror 209 becomes a layer to be selectively oxidized.
The AlAs layer 230 is composed of a GaInP layer and an AlGaAs layer.
A low refractive index layer having a thickness of 3λ / 4 (thickness of (λ / 4-
15 nm) C-doped p-Ga_xIn_1-xP_yAs_1-y(X
= 0.5, y = 1) layer (non-radiative recombination preventing layer) 208,
C-doped p-Al_zGa_1-zAs (z = 1) selective oxidation layer
230 (thickness 30 nm) and thickness (2λ / 4-15n
m) 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)
It is.

In the example of FIG. 3 (not shown in FIG. 3), the semiconductor distributed Bragg reflector 20
4, 209, between the low refractive index layer (layer having a small refractive index) and the high refractive index layer (layer having a large refractive index) as shown in FIG.
Material layer Al _z Ga _{1 -z} As with refractive index between small and large
(0 ≦ y <z <x ≦ 1) is provided.

The uppermost part of the upper reflecting mirror 209 has p
An Al _x Ga _{1 -x} As (x = 0) layer 210 is formed, and this layer 210 also has a function as a contact layer (p-contact layer) for making contact with the p-side electrode 212. ing.

In the surface-emitting type semiconductor laser shown in FIG. 3, the quantum well active layer 206 has an In composition x of 37% and N (nitrogen).
The composition was 0.5%. The thickness of the quantum well active layer 206 was 7 nm.

The growth method of the surface emitting semiconductor laser shown in FIG. 3 was performed by MOCVD. The raw materials constituting each layer of the semiconductor laser include TMA (trimethylaluminum),
TMG (trimethyl gallium), TMI (trimethyl indium), AsH ₃ (arsine), PH ₃ (phosphine), and the raw material of nitrogen was used DMHy (dimethylhydrazine). DMHy decomposes at low temperatures, so
It is suitable for low-temperature growth of 0 ° C. or lower, 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 the example of FIG. 3, the GaInNAs layer (quantum well active layer) was grown at 540 ° C. MOCVD
The method is suitable for crystal growth of a material having a high degree of supersaturation and simultaneously containing N and another V group. 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.

Further, in the example of FIG.
P-Ga_xIn_1-xP_yAs_{1 -y}(X = 0.5, y
= 1) until the layer (non-radiative recombination preventing layer) 208 is reached
p-Al_zGa_1-zAs (z = 1) of the selectively oxidized layer 230
Formed by exposing the side surface,_zGa_1-zA
s (z = 1) layer 230 is oxidized from the side with water vapor to form Al
_xO_yA current narrowing layer 220 is formed.

The portion removed by the mesa etching is buried with polyimide (insulating film) 221 to be flattened, and the polyimide on the upper reflecting mirror 209 is removed.
-P on the contact layer 210 except for the light emitting portion 214
A side electrode 212 is formed, and an n-side electrode 213 is formed on the back surface of the GaAs substrate 201.

In the example of FIG. 3, the selectively oxidized layer 230
Ga _x In _1-x P
_y As _1-y (0 <x <1, 0 <y ≦ 1) layer (non-radiative recombination preventing layer) 208 is inserted. For example, in the case of wet etching, if a sulfuric acid-based etchant is used, A
Since GaInPAs system can be used as an etching stop layer as compared to lGaAs system, Ga _x In _1-x P _y
By inserting the As _1-y (0 <x <1, 0 <y ≦ 1) layer 208, the height of mesa etching for selective oxidation can be strictly controlled. Therefore, uniformity and reproducibility can be improved, and cost reduction can be achieved.

When the surface-emitting type semiconductor laser (element) shown in FIG. 3 is integrated one-dimensionally or two-dimensionally, the controllability at the time of manufacturing the element is improved, and the element characteristics of each element in the array are improved. This has the effect that the uniformity and reproducibility of the film become extremely good.

In this example, Ga _x In _{1-x Py} As _1-y (0 <x <1, 0 <y
<1) Although the layer 208 is provided on the upper reflecting mirror 209 side, it may be provided on the lower reflecting mirror 204 side.

Also, in the example shown in FIG.
Active regions (upper spacer layer 207 and lower spacer layer 2) into which carriers are injected and recombined
05 and a multi-quantum well active layer 206), a material containing Al is not used in the active region, and the lower reflective mirror 204 and the upper reflective mirror 209 are the most active layers of the low refractive index layers. Layer close to Ga _x In _{1-x Py} As _1-y
(0 <x <1, 0 <y ≦ 1) Non-radiative recombination preventing layer 20
3,208. In other words, in the example of FIG. 3, since the structure is such that Al is not contained in the active region and at the interface between the reflector and the active region, non-emission repetition caused by crystal defects caused by Al is caused at the time of carrier injection. Coupling can be reduced.

The configuration in which Al is not contained at the interface between the reflecting mirror and the active region is changed to the upper and lower reflecting mirrors 204 and 204 as shown in FIG.
209 is preferably applied, but it is effective to apply it to only one of the reflecting mirrors. In this example, both the upper and lower reflectors 204 and 209 are semiconductor distributed Bragg reflectors, but one reflector may be a semiconductor distributed Bragg reflector and the other reflector may be a dielectric reflector.

Further, in the example shown in FIG.
1 is applied to the lower reflector 204 between the first active layer 206 and the active layer 206, the active layer 20 having crystal defects caused by Al, which is a problem when the active layer 206 is grown, is used.
6. The negative effect of crawling to 6 is suppressed, and the active layer 2
06 can be grown with high quality.

Incidentally, such a non-radiative recombination preventing layer is
1 and 3 constitute a part of the semiconductor distributed Bragg reflector, the thickness thereof is 、 of the oscillation wavelength λ in the medium (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 can be obtained with the configuration as shown in FIG. Moreover, not all of the low refractive index layer of the semiconductor distributed Bragg reflector _{204,209, Ga x In 1-x} P y As 1-y (0 not containing Al and closest to the least active region <x <1 , 0 <y ≦
Since only the non-emission recombination prevention layers 203 and 208 of 1) were used, the above-described effect was obtained without particularly increasing the number of stacked reflecting mirrors 204 and 209.

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 device having high reliability can be obtained.

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

In the example of FIG. 3, the main elements are Ga, In,
A layer made of N and As was used for the active layer 206 (GaIn
Therefore, a surface-emitting semiconductor laser in a long wavelength band could be formed on the GaAs substrate 201. Al and As
The threshold current was low because the current was narrowed by the selective oxidation of the selectively oxidized layer 230 mainly containing.

According to the current narrowing structure using the current narrowing layer 230 composed of the Al oxide film obtained by selectively oxidizing the selectively oxidized layer 230, the current spreading is suppressed by forming the current narrowing layer 230 close to the active layer 206. As a result, carriers can be efficiently confined in a minute region that does not come into contact with the atmosphere. Further, by oxidizing to form an Al oxide film, the refractive index is reduced, light can be efficiently confined in a minute region in which carriers are confined by the effect of a convex lens, 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 surface emitting semiconductor laser in the 1.3 μm band can be realized in the configuration as shown in FIG. 3, as in the case of FIG. An element is obtained.

The surface-emitting type 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, in the example of FIG. 3, a triple quantum well structure (TQW) is shown as an example of a stacked structure of the active layer 206. However, a structure (SQW, DQW) using quantum wells of other well numbers is used.
W, MQW) and 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. Further, even if GaAsSb is used for the active layer, a surface emitting semiconductor laser in a 1.3 μm band can be realized on a GaAs substrate.

In the case where GaInAs is used for the active layer, conventionally, it has been considered that the maximum wavelength of 1.1 μm is used as a limit for increasing the wavelength.
It becomes possible to grow the As quantum well active layer thicker than before, and the wavelength can reach up to 1.2 μm.

As described above, the wavelength of 1.1 μm to 1.7 μm
Although the semiconductor laser of the prior art did not have a suitable material, the active layer has a high strain of GaInAs, GaInNAs, and GaAsSb.
By using a non-radiative recombination prevention layer,
Wavelength of 1.1 μm to 1.7 μ for which stable oscillation has conventionally been difficult
A long-wavelength band surface emitting semiconductor laser that oscillates stably in the m-band long wavelength region has been realized.

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 (100) plane orientation, 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.

As described above, a long-wavelength surface-emitting semiconductor laser having practical characteristics and an oscillation wavelength of 1.1 μm to 1.7 μm that stably oscillates can be realized.

Such a surface emitting semiconductor laser can be applied to an airborne optical communication system such as an airplane (aircraft) and a spacecraft.

That is, the airborne optical communication system according to the first embodiment of the present invention comprises an active layer, an upper reflector provided above the active layer, and a lower reflector provided below the active layer. A surface-emitting type semiconductor laser having at least a resonator as a light source is used as a light source, and the devices are connected by an optical fiber, and optical communication is performed between the devices by an optical signal from the light source. Here, the surface emitting semiconductor laser has an oscillation wavelength of 1.1 μm to 1.
7 μm, and the main element is Ga, In,
A layer composed of N and As, or a main element composed of Ga and I
The upper reflector and / or the lower reflector are semiconductor distributed Bragg reflectors in which a material layer having a small refractive index and a material layer having a large refractive index are periodically laminated. The material layer with a small refractive index is Al
_x Ga _1-x As (0 <x ≦ 1), the material layer having a large refractive index is Al _y Ga _1-y As (0 ≦ y <x ≦ 1), and the material layer having a small refractive index is refracted. between the rate is large material layer, Al _z as a material layer having a refractive index takes a value between the small and large
A Ga _1-z As (0 ≦ y <z <x ≦ 1) layer is provided.

As described above, there has not been a surface emitting semiconductor laser which has practical characteristics in the 1.1 μm band to 1.7 μm band where the oscillation wavelength is compatible with the optical fiber and stably oscillates. By devising a semiconductor distributed Bragg reflector as in the present invention, an active layer material having good temperature characteristics can be obtained, the operating voltage, the oscillation threshold current, etc. can be reduced, the laser element generates less heat, and stable oscillation can be achieved. In addition, a low-cost and practical long-wavelength band surface emitting semiconductor laser can be realized.

Further, this long-wavelength band surface emitting semiconductor laser is used in an optical communication system between devices in a flying body such as an airplane (aircraft) and a spacecraft, which has conventionally been limited in optical wiring due to the difficulty in weight reduction. By using it, the temperature control equipment and the power supply and battery for operating them are unnecessary or extremely small, so that it is greatly reduced in weight and can be used for aircraft that can transmit signals at high speed with high reliability. An optical communication system can be realized.

Further, the flying object optical communication system according to the second embodiment of the present invention comprises an active layer, an upper reflector provided above the active layer, and a lower reflector provided below the active layer. A surface-emitting type semiconductor laser having at least a resonator as a light source is used as a light source, and the devices are connected by an optical fiber, and optical communication is performed between the devices by an optical signal from the light source. Here, the surface emitting semiconductor laser has an oscillation wavelength of 1.1 μm to 1.7 μm.
m, and the main elements in the active layer are Ga, In, N,
As layer or the main element is Ga, In,
A layer made of As is used, and the upper reflector and / or the lower reflector are semiconductor distributed Bragg reflectors in which a material layer having a small refractive index and a material layer having a large refractive index are periodically laminated. The material layer having a small refractive index is Al _x G
a _1-x is As (0 <x ≦ 1) , a large material layer whose refractive index is _{Al y Ga 1-y As (} 0 ≦ y <x ≦ 1), wherein the upper reflector and the active layer and A non-radiative recombination preventing layer made of GaInP or GaInPAs is provided between the lower reflector and the lower reflector.

As described above, there has been no surface-emitting type semiconductor laser which can be used stably in the 1.1 μm to 1.7 μm band where the oscillation wavelength is compatible with the optical fiber, but as in the present invention. By using a surface emitting semiconductor laser provided with a non-light emitting recombination preventing layer, a long wavelength band surface emitting semiconductor laser having an active layer material having good temperature characteristics and oscillating stably can be realized.

Furthermore, this long-wavelength surface emitting semiconductor laser is used in an optical communication system between devices in an airplane such as an airplane (aircraft) or a spacecraft, which has conventionally been limited in terms of optical wiring due to the difficulty in weight reduction. As a result, the temperature control devices and the power supply and batteries for operating them are unnecessary or extremely small, so that the weight of the light is greatly reduced, and the light for the aircraft that can transmit signals at high speed with high reliability can be obtained. A communication system can be realized.

FIG. 5 is a diagram showing an example of a basic configuration of an optical communication system for a flying object according to the present invention using the above-described long wavelength band surface emitting semiconductor laser. Referring to FIG. 5, in this optical communication system for a vehicle, a communication device 11 and a communication device 15 are connected by an optical fiber 19. Here, the communication device 11 is provided corresponding to the device 12, and has a signal control circuit 13 and a surface emitting semiconductor laser / light receiving element (14). The communication device 15 is provided corresponding to the device 16 and includes a signal control circuit 17 and a surface emitting semiconductor laser / light receiving element (18).

As the surface emitting semiconductor lasers of the surface emitting semiconductor laser / light receiving elements (14) and (18), the above-described long-wavelength band surface emitting semiconductor laser of the first or second embodiment is used. Have been.

The optical fiber 19 is a quartz single mode fiber.

In the optical communication system for a vehicle having the configuration shown in FIG. 5, when an electric signal is output from the device 12, the electric signal from the device 12 is input to the signal control circuit 13 of the communication device 11, and the signal control circuit Reference numeral 13 controls the light emission of the surface emitting semiconductor laser of the surface emitting semiconductor laser / light receiving element (14) according to an electric signal from the device 12. This allows
An optical signal is output from the surface emitting semiconductor laser of the surface emitting semiconductor laser / light receiving element (14).
The light is transmitted to the communication device 15 via the optical fiber 19. In the communication device 15, a surface emitting semiconductor laser /
The light receiving element of the light receiving element (18) receives the optical signal transmitted from the surface emitting semiconductor laser of the communication device 11, converts the optical signal into an electric signal, and transmits the signal to the device 1 via the signal control circuit 17.
Give to 6. Thereby, the signal from the device 12 is transmitted to the device 1
6 can be transmitted.

When an electric signal is output from the device 16, the electric signal from the device 16 is input to a signal control circuit 17 of the communication device 15, and the signal control circuit 17 responds to the electric signal from the device 16. The light emission of the surface emitting semiconductor laser of the surface emitting semiconductor laser / light receiving element (18) is controlled. Thereby, the surface emitting semiconductor laser / light receiving element (1
An optical signal is output from the surface-emitting type semiconductor laser 8), and the optical signal is optically transmitted to the communication device 11 via the optical fiber 19. In the communication device 11, the light receiving element of the surface emitting semiconductor laser / light receiving element (14) receives the optical signal transmitted from the surface emitting semiconductor laser of the communication device 15, converts the optical signal into an electric signal, Signal control circuit 1
3 to the device 12. Thereby, the signal from the device 16 can be transmitted to the device 12.

In this way, optical communication can be performed between the device 12 and the device 16.

As described above, GaInAs or G
A surface emitting semiconductor laser including an aInNAs-based material in an active layer has excellent temperature characteristics. For example, GaInNAs
In the case of an edge-emitting laser having an emission wavelength of 1.3 μm and using an active layer as the active layer, the threshold current density of laser oscillation at room temperature is only 1.3 times even at 80 ° C. On the other hand, in the case of a conventional edge-emitting laser including GaInPAs in an active layer manufactured on an InP substrate, the threshold current density is tripled from 20 ° C. to 80 ° C. This indicates that the light emitting element including the GaInNAs-based semiconductor in the active layer has much better temperature characteristics.

In the system of FIG. 5, such a GaIn
Since a long-wavelength surface-emitting semiconductor laser using the As or GaInNAs-based active layer (the long-wavelength surface-emitting semiconductor laser of the first or second embodiment described above) is used as a light source (light emitting element). Unlike the conventional optical transmission system using a light emitting element containing GaInPAs in an active layer manufactured on an InP substrate, the light emitting element portion does not require a temperature control device such as a Peltier element or a heater and a power supply for operating them. Only a very small one is required, and the weight of the aircraft is significantly reduced.

The long-wavelength surface-emitting type semiconductor laser according to the first or second embodiment described above is different from an edge-emitting type light-emitting device including a GaInPAs formed in an active layer on a conventional InP substrate in an active layer. Because it can be driven with low power consumption,
Only a small power supply is needed. In addition, since it is suitable for high-speed transmission, the number of wirings can be reduced. Further, since a high-density array can be realized, the weight per unit light emitting element can be reduced.

Therefore, when an optical transmission system (optical communication system) using the long-wavelength surface emitting semiconductor laser of the present invention is mounted on an airplane such as an airplane (aircraft) or a spacecraft, the effect of weight reduction is extremely large. large.

Further, the silica-based fiber has a small transmission loss and is most widely used as a medium for optical wiring. Especially 1.
The transmission loss is the smallest in the 3 μm band or 1.5 μm band wavelength region. The long-wavelength surface emitting semiconductor laser of the present invention has an emission wavelength of 1.1 μm by changing the composition.
It can be changed in the above wavelength range. Therefore, G
By making the emission wavelength of the aNAs surface emitting laser 1.3 μm band or 1.5 μm band and optically coupling with a quartz fiber, a signal can be transmitted more reliably and at a higher transmission rate.

The optical fiber may be a silica-based multimode fiber or a silica-based single mode fiber, but a silica-based single-mode fiber is preferred.
This is for the following reason. That is, the diameter of the silica-based multimode fiber is about 100 to 300 μm, while the diameter of the silica-based single mode fiber is about 50 to 100 μm, and the weight per unit length is small. In addition, quartz single-mode fiber has a wider transmission band and longer transmission distance than multi-mode fiber, so it is possible to transmit data at high speed with high reliability. And the number of wirings can be reduced. That is, the weight of the optical transmission system (optical communication system) can be significantly reduced. Therefore, when the optical transmission system (optical communication system) is mounted on a flying object such as an airplane (aircraft) or a spacecraft, the effect of reducing the weight is extremely large. In addition, signal transmission can be performed more reliably and at high speed.

FIG. 6 is a diagram showing an example of an optical communication system for a flying object (an optical communication system for a flying object of a parallel transmission system) according to the present invention using the above-described long wavelength band surface emitting semiconductor laser. Referring to FIG. 6, in this optical communication system for a vehicle, a communication device 21 and a communication device 25 are connected by optical fibers 29-1, 29-2, 29-3, and 29-4. Here, the communication device 21 is provided corresponding to the device 22, and includes a signal control circuit 23 and a plurality of surface emitting semiconductor laser / light receiving elements (24-1, 24-2, 24-
3, 24-4). In addition, the communication device 25
Is provided corresponding to the device 26, and the signal control circuit 27
And a plurality of surface emitting semiconductor lasers / light receiving elements (28-
1, 28-2, 28-3, 28-4).

Then, the surface emitting semiconductor laser / light receiving elements (24-1, 24-2, 24-3, 24-4), (28)
For the surface emitting semiconductor lasers of (-1, 28-2, 28-3, 28-4), the long-wavelength band surface emitting semiconductor laser according to the first or second embodiment described above is used.

The optical fibers 29-1, 29-2, 2
For 9-3 and 29-4, a silica-based single mode fiber is used.

In the optical communication system for a vehicle having the configuration shown in FIG. 6, when an electric signal is output from the equipment 22, the electric signal from the equipment 22 is input to the signal control circuit 23 of the communication device 21, and the signal control circuit Reference numeral 23 denotes a surface emitting semiconductor laser / light receiving element (24-1, 2-2) according to an electric signal from the device 22.
4-2, 24-3, and 24-4) to drive and control the emission of the plurality of surface emitting semiconductor lasers. Thereby, the surface-emitting type semiconductor laser / light-receiving element (24-1, 24-2, 24-
From the plurality of surface emitting semiconductor lasers of 3, 24-4),
An optical signal is output, and this optical signal is
The light is transmitted to the communication device 25 via 1, 29-2, 29-3, and 29-4. In the communication device 25, the surface emitting type semiconductor laser / light receiving element (28-1, 28-2, 28
-3, 28-4) receive the optical signals transmitted from the plurality of surface-emitting type semiconductor lasers of the communication device 21 and convert the optical signals into electrical signals, via the signal control circuit 27. To the device 26. Thereby, the signal from the device 22 can be transmitted to the device 26.

When an electric signal is output from the device 22, the electric signal from the device 22 is input to a signal control circuit 27 of the communication device 25, and the signal control circuit 27 responds to the electric signal from the device 26. The drive of the plurality of surface emitting semiconductor lasers of the surface emitting semiconductor lasers / light receiving elements (28-1, 28-2, 28-3, 28-4) is controlled. Thereby, the surface emitting type semiconductor laser / light receiving element (28-1, 28)
-2, 28-3, 28-4), an optical signal is output from the plurality of surface emitting semiconductor lasers, and the optical signal is output to optical fibers 29-1, 29-2, 29-3, 29-4. Is optically transmitted to the communication device 21 via the. In the communication device 21, the surface-emitting type semiconductor laser / light-receiving element (24-1, 2-2)
4-2, 24-3, and 24-4) receive the optical signals transmitted from the plurality of surface emitting semiconductor lasers of the communication device 25, convert the optical signals into electric signals, and This is given to the device 22 via the control circuit 23. Thereby, the signal from the device 26 can be transmitted to the device 22.

Thus, optical communication can be performed between the device 22 and the device 26. As described above, in the optical communication system for a vehicle shown in FIG. 6, a parallel transmission method using a plurality of optical fibers is used for optical communication between the devices 22 and 26. That is, signals from a plurality of long wavelength band surface emitting semiconductor lasers are simultaneously transmitted using a plurality of optical fibers. 2. Description of the Related Art In an air vehicle such as an air vehicle (aircraft) and a spacecraft, a distributed processing system is required by a plurality of computers. In the case of a spacecraft in which a plurality of modules are combined, a computer may be mounted on each module. In some cases, the spacecraft alone may be equipped with a plurality of computers having the same configuration and perform the same arithmetic processing to increase the reliability of the arithmetic processing. Transmission between these computers needs to be fast and large,
In the case of the time division multiplex transmission, the correspondence becomes insufficient. If a parallel transmission method using a plurality of optical fibers is adopted as shown in FIG. 6, high-speed and large-capacity transmission becomes possible, and the above-mentioned plurality of computer systems can be connected.

Therefore, in the configuration shown in FIG. 6, optical signal transmission of high-speed and large-capacity data is possible, which is suitable for data transmission between computers, and is suitable for optical communication for air vehicles such as airplanes (aircraft) and spacecraft. It becomes possible to provide a system.

FIG. 7 is a diagram showing an example of a flying object optical communication system (multi-wavelength transmission type flying object optical communication system) of the present invention using the above-described long-wavelength band surface emitting semiconductor laser. . Referring to FIG. 7, in this optical communication system for a vehicle, a communication device 31 and a communication device 36 are connected by an optical fiber 45. Here, the communication device 31
Are provided corresponding to the device 32, and the signal control circuit 33
And a surface emitting semiconductor laser / light receiving element (34-1, 34)
−2, 34-3, 34-4) and a multiplexer / demultiplexer (3
5). Further, the communication device 36 includes a device 37.
And a signal control circuit 38 and a surface-emitting type semiconductor laser / light-receiving element (39-1, 39-2, 39-
3, 39-4) and a multiplexer / demultiplexer (40).

Then, the surface emitting semiconductor laser / light receiving elements (34-1, 34-2, 34-3, 34-4), (39)
-1, 39-2, 39-3, and 39-4) use the long-wavelength band surface-emitting semiconductor laser of the first or second embodiment described above.

The surface emitting type semiconductor laser / light receiving element (34-1, 34-2, 34-3, 34-4) and the multiplexer / demultiplexer (35) are connected to the optical fiber 41-1. 41-
2, 41-3, 41-4, and a surface-emitting type semiconductor laser / light-receiving element (39-1, 39-2, 39-
3, 39-4) and the multiplexer / demultiplexer (40) are connected by optical fibers 42-1, 42-2, 42-3, 42-4.

The optical fibers 45, 41-1, 41-
2,41-3,41-4,42-1,42-2,42-
For 3, 42-4, a silica-based single mode fiber is used.

In the optical communication system for a vehicle having the configuration shown in FIG. 7, when a plurality of electric signals are output from the device 32, the plurality of electric signals from the device 32 are input to the signal control circuit 33 of the communication device 31. , The signal control circuit 33 responds to each of a plurality of electric signals from the device 32 by using a surface-emitting type semiconductor laser / light-receiving element (34-1, 34-2, 34-3, 34).
And 4) driving and controlling the light emission of the plurality of surface emitting semiconductor lasers. Thus, a plurality of surface emitting semiconductor lasers of the surface emitting semiconductor laser / light receiving element (34-1, 34-2, 34-3, 34-4) output optical signals having different wavelengths, respectively. The optical signal of the optical fiber 41-
1, 41-2, 41-3, and 41-4, add to the multiplexer of the multiplexer / demultiplexer (35), are multiplexed by the multiplexer, and are transmitted through the optical fiber 45 to the communication device. The light is transmitted to 36.
In the communication device 36, the optical signal from the optical fiber 45 is demultiplexed by the demultiplexer of the multiplexer / demultiplexer (40), and the optical fibers 42-1, 42-2, 42-3, and 42-4 are demultiplexed. Surface emitting semiconductor laser / light receiving element (39-1, 39-2,
39-3, 39-4).
Each light receiving element receives the divided optical signals having different wavelengths, converts each optical signal into an electric signal, and generates a signal.
To the device 37 via the. Thus, a signal from the device 32 can be transmitted to the device 37.

When a plurality of electric signals are output from the device 37, the plurality of electric signals from the device 37 are input to the signal control circuit 38 of the communication device 36, and the signal control circuit 38
Are surface emitting semiconductor lasers / light receiving elements (39-1, 39-
2, 39-3, 39-4) to drive and control the emission of the plurality of surface emitting semiconductor lasers. Thereby, the surface-emitting type semiconductor laser / light receiving elements 39-1, 39-2, 39-3, 39
-4 output light signals having different wavelengths from each other, and these light signals are combined via optical fibers 42-1, 42-2, 42-3, and 42-4. The light is added to the multiplexer of the optical multiplexer / demultiplexer 40, is multiplexed by the optical multiplexer, and is optically transmitted to the communication device 31 via the optical fiber 45. In the communication device 31, the optical signal from the optical fiber 45 is split by the splitter of the multiplexer / demultiplexer (35).
A surface-emitting type semiconductor laser / light-receiving element (34-1, 3
4-2, 34-3, and 34-4). Each light receiving element receives the separated optical signals having different wavelengths, converts each optical signal into an electric signal, and supplies the electric signal to the device 32 via the signal control circuit 33. Thereby, the signal from the device 37 can be transmitted to the device 32.

Thus, optical communication can be performed between the device 32 and the device 37.

That is, in the system of FIG. 7, each of a plurality of electric signals output from one or a plurality of devices is converted into a plurality of optical signals having different wavelengths by a plurality of surface emitting semiconductor lasers. A plurality of optical signals having different wavelengths are introduced into the multiplexer through an optical fiber, multiplexed by the multiplexer, introduced into one optical fiber, and transmitted. The transmitted optical signal is separated into a plurality of original optical signals having different wavelengths through a demultiplexer connected to a transmission destination device, and is input to a plurality of light receiving elements via optical fibers, respectively, and the electric signal is transmitted. And the signal is transmitted to this other device.

As described above, in the optical communication system for air vehicles shown in FIG. 7, a multi-wavelength transmission system for simultaneously transmitting a plurality of optical signals having different wavelengths through one optical fiber is used for optical communication between devices. Since optical signals of a plurality of wavelengths are transmitted by one optical fiber, the number of optical wirings can be reduced. This makes it possible to significantly reduce the weight of the optical communication system, and is extremely effective when the optical communication system is mounted on a flying object such as a flying object (aircraft) or a spacecraft. Further, it is possible to provide an optical communication system for a flying object such as an airplane (aircraft) or a spacecraft, which is capable of high-speed large-capacity transmission and suitable for data transmission between computers.

In the examples of FIGS. 5, 6, and 7, the simplest optical wiring configuration of the optical communication system for a flying object of the present invention for transmitting and receiving an optical signal between two communication devices is shown. In the optical communication system for air vehicles according to the present invention, any optical wiring form can be adopted. For example, as an optical wiring form, LAN
Like a wiring form in (Local Area Network), a bus type, a star type, a tree type, a ring type, and the like can be adopted.

FIG. 8 is a diagram showing a configuration example of a flying object provided with an optical communication system for a flying object. In the example of FIG.
The flying object is an aircraft.

Referring to FIG. 8, this flying object (aircraft)
In the navigation control computer 60, the manual control device 61, the wing drive servo device 62, the propulsion device control device 6
3. Devices such as a radar device 64 and an airframe monitoring device 65 are optically wired in a star shape by optical fibers.

Here, between the aviation control computer 60 and the manual operation device 61, the aviation control computer 60
Between the aviation control computer 60 and the propulsion device control device 63, between the aviation control computer 60 and the radar device 54, and between the aviation control computer 60 and the airframe monitoring device 65. Since the optical communication system of the embodiment shown in FIG. 5, FIG. 6 or FIG. 7 has been constructed, the optical communication system capable of transmitting signals is lightweight, highly reliable, has a high transmission speed, can cope with a large capacity, and can transmit signals. An aircraft equipped with the system can be realized.

FIG. 9 is a diagram showing another example of the configuration of the flying object provided with the optical communication system for the flying object.
In the example, the vehicle is a spacecraft.

Referring to FIG. 9, this flying object (spacecraft)
Now, the three flight controllers 72 in the central module 71
-1, 72-2, and 72-3 are optically wired to each other by an optical fiber in a ring shape.

The small-sized modules 74-1, 74-2, 74 are provided to the central computer 73 in the central module 71.
Small computers 75-1, 75-2, 75-
3 is optically wired in a star shape by an optical fiber.

Here, the three flight controllers 72-1, 7
An optical communication system of the form shown in FIG. 5, FIG. 6, or FIG. 7 is constructed between 2-2 and 72-3 and between the central computer 73 and the small computers 75-1, 75-2 and 75-3. So it is lightweight, reliable, with high transmission speeds,
It is possible to realize a spacecraft equipped with an optical communication system capable of transmitting signals, which can cope with an increase in capacity.

[0138]

As described above, according to the first aspect of the present invention, the active layer, the upper reflector provided above the active layer, and the lower reflector provided below the active layer. A surface emitting semiconductor laser having at least a resonator as a light source is used as a light source, the devices are connected by an optical fiber, and optical communication is performed between the devices by an optical signal from the light source. In the optical communication system for use, the surface-emitting type semiconductor laser has an oscillation wavelength of 1.1 μm to 1.7 μm, and the active layer mainly includes a layer made of Ga, In, N, or As, or a main element. A layer made of Ga, In, and As is used, and the upper reflector and / or the lower reflector is a semiconductor distribution board in which a material layer having a small refractive index and a material layer having a large refractive index are periodically laminated. The material layer having a small refractive index in the Ragg reflector is Al _x Ga _{1 -x} As (0 <x ≦ 1),
The material layer having a large refractive index is Al _y Ga _{1 -y} As (0 ≦ y <x
≦ 1), and between a material layer having a small refractive index and a material layer having a large refractive index, Al _z Ga _{1 -z} As (0 ≦ Since the y <z <x ≦ 1) layer is provided, it is possible to realize an optical communication system for a vehicle that is significantly reduced in weight and can transmit signals at high speed with high reliability.

That is, there has not been a surface emitting type semiconductor laser which has practical characteristics in the 1.1 μm band to 1.7 μm band where the oscillation wavelength is compatible with the optical fiber and oscillates stably. By devising a semiconductor distributed Bragg reflector as in the invention of the first aspect, it is possible to use an active layer material having good temperature characteristics, reduce operating voltage, oscillation threshold current, etc., generate less heat from the laser element, and achieve stable oscillation. ,
In addition, a low-cost and practical long-wavelength band surface emitting semiconductor laser can be realized.

In addition, this long-wavelength surface emitting semiconductor laser is used in an optical communication system between devices in a flying body such as an airplane (aircraft) and a spacecraft, which has conventionally been limited in optical wiring due to the difficulty in weight reduction. As a result, the temperature control devices, the power supply for operating them, and the batteries required for operation are unnecessary or extremely small. A communication system can be realized.

According to the second aspect of the present invention, at least the active layer, the upper reflector provided above the active layer and the lower reflector provided below the active layer are provided as resonators. A surface-emitting type semiconductor laser is used as a light source, the devices are connected by an optical fiber, and an optical communication system for a flying object in which optical communication is performed between the devices by an optical signal from the light source, The surface-emitting type semiconductor laser has an oscillation wavelength of 1.1 μm to 1.7 μm.
μm, and the main element is Ga, In,
A layer composed of N and As, or a main element composed of Ga and I
The upper reflector and / or the lower reflector are semiconductor distributed Bragg reflectors in which a material layer having a small refractive index and a material layer having a large refractive index are periodically laminated. The material layer with a small refractive index is Al
an _{x Ga 1-x As (0} <x ≦ 1), a large material layer whose refractive index is _{Al y Ga 1-y As (} 0 ≦ y <x ≦ 1), wherein the upper reflector and the active layer And / or a non-light-emitting recombination preventing layer made of GaInP or GaInPAs is provided between the lower reflector and the lower reflecting mirror, so that the weight of the vehicle is significantly reduced, and the aircraft can transmit signals at high speed with high reliability. An optical communication system for use can be realized.

That is, there has been no surface emitting semiconductor laser which can be used stably in the 1.1 μm band to 1.7 μm band in which the oscillation wavelength is compatible with the optical fiber. By using a surface emitting semiconductor laser provided with a non-light emitting recombination preventing layer, a long wavelength band surface emitting semiconductor laser having an active layer material having good temperature characteristics and oscillating stably can be realized.

In addition, this long-wavelength surface emitting semiconductor laser is used in an optical communication system between devices in a flying body such as an airplane (aircraft) or a spacecraft, which has conventionally been limited in optical wiring due to the difficulty in weight reduction. As a result, the temperature control devices, the power supply for operating them, and the batteries required for operation are unnecessary or extremely small. A communication system can be realized.

According to a third aspect of the present invention, in the optical communication system for an air vehicle according to the first or second aspect, the optical fiber is a silica-based single mode fiber, and a silica-based single mode fiber is used as a communication medium. Since the single mode fiber is used, the weight of the optical communication system can be further reduced, and an optical communication system for an airplane capable of transmitting a signal with higher reliability and higher speed can be realized.

According to a fourth aspect of the present invention, in the optical communication system for an air vehicle according to the first or second aspect, a parallel transmission system using a plurality of optical fibers for optical communication between devices. Is used, and the transmission method is parallelized, so that high-density, large-capacity data optical communication is possible, suitable for data transmission between computers.
An optical communication system for a flying object can be realized.

According to the fifth aspect of the present invention, in the optical communication system for an air vehicle according to the first or second aspect, for optical communication between devices, wavelengths are different in one optical fiber. A multi-wavelength transmission method for simultaneously transmitting a plurality of optical signals has been used, and since the transmission method is multi-wavelength transmission, the number of optical wirings can be reduced, and the optical transmission device is greatly reduced in weight. In addition, an optical communication system for a flying object capable of high-speed and large-capacity transmission can be realized.

According to a sixth aspect of the present invention, there is provided a flying object equipped with the optical communication system for a flying object according to any one of the first to fifth aspects. It is equipped with an optical communication system that is lightweight, reliable, has a high transmission speed, and can transmit signals in response to large capacity, so advanced and reliable control of the lightweight aircraft A flying object equipped with the system can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of a surface emitting semiconductor laser used in an optical communication system for a flying object according to the present invention.

FIG. 2 is a diagram showing an example of a partial configuration of a semiconductor distributed Bragg reflector of a surface emitting semiconductor laser used in an optical communication system for a vehicle according to the present invention.

FIG. 3 is a diagram illustrating another configuration example of a long-wavelength surface emitting semiconductor laser used in the optical communication system for a flying object according to 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 is formed.

FIG. 5 is a diagram showing an example of a basic configuration of an optical communication system for a flying object of the present invention using a long-wavelength band surface emitting semiconductor laser.

FIG. 6 is a diagram illustrating an example of an optical communication system for a flying object (an optical communication system for a flying object of a parallel transmission system) of the present invention using a long wavelength band surface emitting semiconductor laser.

FIG. 7 is a diagram illustrating an example of an optical communication system for a flying object of an optical communication system for a flying object (multi-wavelength transmission system) of the present invention using a long-wavelength band surface emitting semiconductor laser.

FIG. 8 is a diagram illustrating a configuration example of a flying body provided with an optical communication system for a flying body.

FIG. 9 is a diagram showing another configuration example of the flying object provided with the optical communication system for the flying object.

[Explanation of symbols]

 11,15 communication device 12,16 equipment 13,17 signal control circuit 14,18 surface emitting semiconductor laser / light receiving element 19 optical fiber 21,25 communication device 22,26 equipment 23,27 signal control circuit 24,28 surface emission type Semiconductor laser / light receiving element 29 Optical fiber 31, 36 Communication device 32, 37 Equipment 33, 38 Signal control circuit 34, 39 Surface emitting semiconductor laser / light receiving element 35, 40 Multiplexer / demultiplexer 41, 42, 45 Light Fiber 60 Navigation control computer 61 Manual control device 62 Wing drive servo device 63 Propulsion device control device 64 Radar device 65 Aircraft monitoring device 71 Central module 72 Flight control device 73 Central computer 74 Small module 75 Small computer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04B 10/02 (72) Inventor Takashi Takashi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Naoto Ashitani 1-36 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. 5F045 AA04 AB09 AB10 AB17 AB18 AC01 AC08 AC12 AD09 AF04 AF13 BB08 BB16 CA12 DA52 DA55 DA64 5F073 AA08 AA63 AA74 AB17 BA02 CA05 CA17 CB02 DA05 EA29 5K002 BA13 BA21 GA07

Claims (6)

[Claims] 1. A surface-emitting type semiconductor laser having at least an active layer, an upper reflector provided above the active layer and a lower reflector provided below the active layer as a resonator is used as a light source. In an optical communication system for a vehicle, the devices are connected by an optical fiber, and optical communication is performed between the devices by an optical signal from the light source, the surface emitting semiconductor laser has an oscillation wavelength. The active layer is a layer whose main element is made of Ga, In, N, As or a layer whose main element is made of Ga, In, As. and / or the lower reflector, a semiconductor distributed Bragg reflector having a refractive index smaller material layer and the refractive index is a large material layer are periodically stacked, the refractive index is small material layer Al _x a _{a 1-x As (0 <} x ≦ 1),
The material layer having a large refractive index is Al _y Ga _{1 -y} As (0 ≦ y <x
≦ 1), and between a material layer having a small refractive index and a material layer having a large refractive index, Al _z Ga _{1 -z} As (0 ≦ An optical communication system for a flying object, comprising a layer of y <z <x ≦ 1). 2. A surface emitting semiconductor laser having at least an active layer, an upper reflector provided above the active layer and a lower reflector provided below the active layer as a resonator is used as a light source. In an optical communication system for a vehicle, the devices are connected by an optical fiber, and optical communication is performed between the devices by an optical signal from the light source, the surface emitting semiconductor laser has an oscillation wavelength. 1.1 μm to 1.7 μm, and a layer whose main element is Ga, In, N, As or a layer whose main element is Ga, In, As is used for the active layer. and / or the lower reflector, a semiconductor distributed Bragg reflector having a refractive index smaller material layer and the refractive index is a large material layer are periodically stacked, the refractive index is small material layer Al _x a _{a 1-x As (0 <} x ≦ 1),
The material layer having a large refractive index is Al _y Ga _{1 -y} As (0 ≦ y <x
≤1), and GaInP or GaI is provided between the active layer and the upper and / or lower reflectors.
An optical communication system for a flying object, comprising a non-radiative recombination prevention layer made of nPAs. 3. The optical communication system for a vehicle according to claim 1, wherein the optical fiber is a silica-based single mode fiber. 4. The flying object optical communication system according to claim 1, wherein a parallel transmission method using a plurality of optical fibers is used for optical communication between the devices. Optical communication system. 5. An optical communication system for an air vehicle according to claim 1, wherein multi-wavelength transmission for simultaneously transmitting a plurality of optical signals having different wavelengths in one optical fiber is used for optical communication between devices. An optical communication system for a flying object, wherein a system is used. 6. A flying object equipped with the optical communication system for a flying object according to any one of claims 1 to 5.