JPH0497206A - Semiconductor optical element - Google Patents

Abstract

PURPOSE:To easily obtain the coupling to an optical fiber as an SLA element by forming a 1st optical waveguide which has odd points of bent parts each having a total reflection surface and disposing the total reflection surfaces in such a manner as to be perpendicular to or parallel with a 1st reference plane. CONSTITUTION:The 1st optical waveguide 6 is formed on a semiconductor 11 and the 2nd optical waveguide 3 having the 1st reference plane 4 and the 2nd reference plane 1 disposed in parallel therewith is provided. The 1st optical waveguide 6 has odd points of the bent parts 42a and is disposed so that the total reflection surfaces 42b of the bent parts 42a are paralleled with the plane in the direction perpendicular to the 1st reference plane 4. Light rays 5, 5' emitted or made incident by the direction of the surface determined as the 1st reference plane 4 are paralleled with the 1st reference plane 4 and the 2nd optical waveguide 3 is disposed perpendicularly to the 1st reference plane 4. The total reflection surfaces 42b of the bent parts 32a of the 1st optical waveguide 6 are also paralleled with the 1st reference plane 4. The optical coupling is easily executed between the semiconductor light emitting element and the optical fiber in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical waveguide provided on a semiconductor substrate.

That is, the present invention relates to a semiconductor optical device in which the angle of the end face of an optical waveguide is set according to Snell's law so that light is emitted perpendicularly or parallel to a reference plane.

[Prior art] Low coherent light emitting device (5upper Lum1nes)
centDiode (so-called 5LD), semiconductor optical direct amplification element (Sesiconductor La5er A
An outline of the mplifier (so-called 5LA) will be explained below.

Low coherent light emitting device (hereinafter referred to as -rSLDJ)
is an element that has an optical waveguide with optical gain and suppresses laser oscillation. As a result of this, in the front stage of the laser emission, a relatively wide optical spectrum width is produced.
Light-emitting diode
(hereinafter referred to as rLED), higher light output can be obtained. Since this SLD has low coherence, it is essentially less likely to generate speckle noise that causes return light noise and interference in light sources, optical fibers, optical disks, etc. Also, it has a wide optical spectrum width and can be used as an approximate white light source. In recent years, it has been actively developed for optical measurement.

Further, a semiconductor optical direct amplification element (hereinafter referred to as "rSLA") is an element that provides optical gain to an optical waveguide by current injection and suppresses laser oscillation, and is placed in the middle of an optical transmission line. Currently, SLA can directly amplify an optical signal by about 20 dB even including fiber coupling loss with an optical transmission line.

This SLA is capable of wide-band optical amplification due to its optical spectral characteristics, and can be integrated with a semiconductor laser (hereinafter referred to as rLDJ) made from the same material. Therefore, there is an urgent need to develop it as a core element for long-distance, high-speed, large-capacity optical communication networks, including future optical switching systems.

The basic operations of SLD and SLA described above are as follows:
The condition is that the component of light reflection at the end face of the optical waveguide that is coupled to the optical waveguide is suppressed. Furthermore, they have in common that even when the injection density is increased, it is necessary to prevent laser oscillation from occurring.

As described above, the basic operation of an SLD etc. needs to be performed under a condition in which the component coupled to the optical waveguide among the light reflections at the end face of the optical waveguide of the LD is suppressed.

In order to suppress the components coupled to the optical waveguide, that is, to reduce the coupling reflectance of the optical waveguide (hereinafter referred to as "optical waveguide coupling reflectance"), the following four methods are generally known. .

■ Apply an anti-reflection film to the end face of the LD optical waveguide.

■ A light absorption region is provided at the end of the optical waveguide to absorb reflected light.

■ A so-called window area is created by embedding a material that does not absorb light at the end of the optical waveguide, so that the light emitted from the optical waveguide,
and diffuse the light reflected within the window area. This suppresses the components of the reflected light that are coupled to the optical waveguide.

(2) The optical waveguide is provided at an angle with respect to the end face from which light is emitted, and the component reflected from the end face and coupled to the optical waveguide is suppressed.

However, the methods from ■ to ■ have the following problems.

Regarding ■, there are the following problems.

When using a non-reflective film, in order to achieve a reflectance ≦10-1, it is necessary to control the layer thickness within 6 nI and the refractive index within 0.05 (for example, the IEICE Technical Research Report OQ , H84-93, pp, 29-[1,36 Saito, Mukaiben, Mikami).

Furthermore, it has been reported that both TE and TH modes cannot be reduced to the same level at the same time (for example,
G, A, ^1pbonse et al, Appli
ed Physi-cs Letters, Vol.
55+ No, 22 2L November 198
9pp, 22B9-pp, 2291).

Furthermore, since this method of using a non-reflective film relies on the resonance phenomenon of light waves, it is not possible to achieve a stable low reflectance over a wide range of light wavelengths.

Regarding ■, there are the following problems.

When a light absorption region is provided at the end of an optical waveguide, this region acts as a saturable absorber, and as a result, the light absorption changes rapidly with the light density threshold in the optical waveguide as a boundary, and this change In this case, crystal defects unintentionally introduced during crystal growth and device formation become non-radiative recombination centers. Therefore, due to manufacturing, variations occur in the light absorption characteristics and their characteristics over time, making it difficult to obtain stable device characteristics.Furthermore, the light absorption region formed at the end of the optical waveguide Alternatively, since the emitted light is attenuated, a direct optical amplification element cannot be obtained.

Regarding ■, there are the following problems.

The window region is a material that removes light reflection at the boundary between the end of the optical waveguide and the window region (is it made of the same material that forms the optical waveguide?
An optical waveguide in contact with a window region, which refers to a region formed by a material with a similar refractive index to the end surface of an optical waveguide and having a termination surface separated by a certain length from the end surface of the optical waveguide. Light that enters the window area from the end face of the window diffuses through the window area and returns to the end face of the optical waveguide via the end face of the window area.As a result, the light passes through the end face of the optical waveguide due to the diffusion. However, the component that returns into the optical waveguide is significantly suppressed.

However, for example, Ga has an embedded structure.

I n +-* A S y P I-y / I n
In P compound semiconductor optical devices, light reflection at the boundary between the end face of the optical waveguide and the window region cannot be sufficiently suppressed. Although the window region is formed by crystal growth using the compound semiconductor system, the crystal growth of the compound semiconductor on the end face of the optical waveguide generally has poor reproducibility.

Further, since the transmission of light is disturbed at the boundary between the end surface of the optical waveguide and the window region, the near-field image and far-field image of the light emitted from the end surface of the window region are disturbed. Therefore, when the emitted light is input to the optical fiber, there is a problem that the proportion of the emitted light that can be input is reduced.

[Problem to be solved by the invention]

Compared to the above methods ① to ②, the method ② in which the optical waveguide is provided at an angle with respect to the light emitting end face and the component coupled to the optical waveguide due to the end face reflection is suppressed is simpler and less feasible. be.

However, ■ also has the following problems.

First, a method for forming an element with an inclined optical waveguide is, for example, in the case of an element that employs an optical waveguide having a refractive index waveguide mechanism (hereinafter referred to as a "refractive index waveguide"), a first conductive waveguide is formed on an InP substrate. type InP buffer layer, GaI n I-x A S
A stripe-shaped etching mask is formed on a double hetero substrate formed by sequentially growing crystals of a y P + -y active layer and second conductivity type InP.

Further, the active layer is etched into a mesa shape to form a mesa stripe that will later become a refractive index waveguide.

At this time, the direction of the mesa stripe is set so as not to coincide with the surface direction of the light emitting end face.

Subsequently, the mesa stripe was coated with second conductivity type InP and first conductivity type InP except for the part covered by the mask.
By sequentially growing the layers, a buried layer is formed and the device structure is completed. In such a configuration, the light emitted from within the optical waveguide after passing through the end surface of the optical waveguide has a difference between the sine of the angle with respect to the virtual normal to the end surface of the optical waveguide before and after passing through the end surface of the optical waveguide. It must satisfy Snell's law, which states that the product of the refractive index of the medium is conserved.

Therefore, the inclination angle of the optical waveguide and the light output angle are in a relationship such that as the inclination angle of the optical waveguide is increased in order to obtain a lower reflectance, the direction of the emitted light moves away from the normal direction of the light output end face.

This relationship is shown in FIGS. 12 and 13.

To explain with reference to FIG. 12, the light emitting end face 7 is formed by cleavage. In the process of bonding the element having the inclined optical waveguide 6 to the heat sink 12 such as a diamond, the light emitting end surface 7 is used as a reference for setting the direction. The light propagating inside the optical waveguide 6 which is inclined by θi with respect to the normal direction 8 of the separated light output end face 7 is emitted by the output light 5 having an angle of θr in FIG. 12 according to Snell's law. becomes.

As a result, the optical fibers coupled to the device having the inclined optical waveguide 6 cannot be arranged in a straight line.

Furthermore, when the inclination of the optical waveguide 6 is made large in this way, the optical fiber that receives the emitted light 5 is also inevitably inclined, so in order to improve the light receiving efficiency of the optical fiber, it is necessary to For example, the end surface 7 and the optical fiber end are
It is necessary to bring them close to each other on the order of 0 μm. In fact, the end of the optical fiber comes into contact with the light emitting end surface 7.

The same can be said when this element structure is applied to SLA. That is, the signal light 5'' that enters the light output end face 7 of one optical waveguide 6 that faces the optical fiber end face of this element at an angle from the end face of one optical fiber is output from the other optical waveguide 6 of this element. The amplified output light 5 is outputted from the end face 7 to the other optical fiber end face that faces the light output end face 7 of the optical waveguide 6 at an angle. -Signal light 5"
Since the traveling direction of the light is refracted at both the light output end faces 7 of the optical waveguide 60 of this element, the signal-light 5 is
” and the traveling direction of the emitted light 5 coincide with each other, but they do not exist on a straight line.
In order to incorporate A into an optical fiber transmission line, a method is adopted in which a region slightly longer than the SLA element length is cut out of the optical fiber transmission line that transmits the signal light, and the SLA element is placed in that part. has been done. However, in the element structure (2), a problem arises in that the signal light incident on the SLA element and the amplified output light emitted from this element are not aligned in a straight line.

The present invention provides an SLD with an inclined optical waveguide 6 and an SLD with an inclined optical waveguide 6.
This was done in view of the above-mentioned circumstances in LA, and even if the optical waveguide coupling reflectance of the optical waveguide 6 is strongly suppressed, the primary purpose is to improve the output light 5 and the optical fiber. Furthermore, the signal light 5° incident on the light output end face 7 of one optical waveguide 6 of the SLA element, and the amplified output light 5 emitted from the light output end face 7 of the other optical waveguide 6 of the SLA element, - It is an object of the present invention to provide a semiconductor optical device that exists on a straight line and can be easily coupled to an optical fiber even as an SLA device.

[Means to solve the problem]

In order to solve the above problems, in the semiconductor optical device of the present invention, the relationship between the direction of the optical waveguide 6 through which light is guided and the direction of the first reference surface 4 which is the exit surface from which the light is emitted is determined. The optical waveguide 6 is set in accordance with Snell's law, and is configured with bent portions 42a at odd locations having total reflection surfaces 42b. That is, this semiconductor optical device is: (1) formed on a semiconductor 11, and the first optical waveguide 6 is formed on the semiconductor 11; According to Snell's law, this optical waveguide 6 allows the guided light 9 to reach the first reference plane 4.
It has one light output waveguide end face 2 having an angle such that light 5 is emitted (or incident on it) in a direction perpendicular to the light output waveguide.

(2) A second optical waveguide 3 having a second reference plane 1 arranged parallel to the first reference plane 4.

(2) The first optical waveguide 6 has bent portions 42a at an odd number of locations.

■Total reflection surface 4 of bent portion 42a of first optical waveguide 6
2b is arranged so as to be parallel to a plane perpendicular to the first reference plane 4.

Note that depending on the direction of the plane defined as the first reference plane 4, the emitted or incident light 5.5' becomes parallel to the first reference plane 4, and the second optical waveguide 3 becomes parallel to the first reference plane 4. It is arranged perpendicularly to the surface 4, and the total reflection surface 42b of the bent portion 42a of the first optical waveguide 6 is also parallel to the first reference surface 4.

[Effect]

According to the semiconductor optical device configured in this way, the optical fibers for input and output light coupled to the device can be arranged with their optical axes aligned in a straight line (or in parallel).

In addition, the directional force of the output light 5 from the light output optical waveguide end face 2 of the optical waveguide 6 formed by etching (conditions that match the normal direction 8 of the first reference plane 40, for example, G a x
I n r-x A sy P I-y / I
When applied to n P (λg-1, 55 μm), the relationship established between the optical waveguide 6 and the first reference plane 4, which is the light output end face, is shown in FIGS. 3 and 4. is the angle θn
is the inclination of the optical waveguide 6 with respect to the light emitting optical waveguide end surface 2, and the angle θf is the inclination of the light emitting optical waveguide end surface 2 with respect to the direction 8.
The angle θi schematically shows the inclination of the optical waveguide 6 with respect to the direction 8''. In FIG. 4, these θn, θf,
The relationship established between θf is shown in a graph.

Here, since the light 5 emitted from the light output optical waveguide end face 2 of the optical waveguide 6 is parallel to the direction 8, θt=θi.

From Figure 4, G a x I n +-x A sy
In the case of an optical waveguide made of P I-x / InP (λg = 1.55 μm), when θf is -45° as shown by the broken line, θnζ is 12.5°, and as shown by the -dotted chain line, θt
L=, 32.4°. Also, θf for the light 9 traveling through the first optical waveguide 6 to be totally reflected by the total reflection surface 42b.
The upper limit value (ζ72°) is indicated by an outline arrow (+=) with θ− on the axis. From this FIG. 4, an example of the optical waveguide coupling reflectance with such a configuration in which the light 9 is totally reflected at the total reflection surface 42b and fulfills the intended function when θf is in the range of 0° to 90° is shown as follows. It is shown in FIG. 8 as a function of the inclination angle θn of the first optical waveguide 6 with respect to the light output optical waveguide end face 2. The optical waveguide coupling reflectance decreases rapidly with θn, for example,
In a crystal system having a Ga1nAsP active layer with a layer thickness of 0.15 μm and a bandgap wavelength of 1.55 μm, if the direction of the light output waveguide end face 2 is inclined at 45° with respect to the normal direction 8, in the refractive index waveguide. Also, an optical waveguide coupling reflectance of 5XIO-' or less can be obtained.

〔Example〕

In the configuration of the present invention, the vertical light output optical waveguide end face 2 is formed so that the output light 5 is perpendicular or horizontal to the first reference plane 4 . On the other hand, the first optical waveguide 6 has bent portions 42a at an odd number of locations,
The bent portion 42a of the first optical waveguide 6 is parallel to the surface 10 formed on the semiconductor substrate 11, and furthermore, the bent portion 42a of the first optical waveguide 6 travels through the first optical waveguide 6 in the exposed portion of the formed first optical waveguide 6. The bending angle of the first optical waveguide 6 is set so that the light 9 acting as a total reflection end face 42b causes total reflection. Also, a light output optical waveguide end face 2 formed on the semiconductor substrate 11 and for outputting or inputting light.
A line segment j connecting the centers of 2” and 2” is parallel to the surface 10,
In addition, total reflection end faces 42b are provided at an odd number of locations.

An embodiment of the semiconductor optical device of the present invention will be described below with reference to the drawings.

(First example) Figure 1 shows an overhead view, and Figure 2 shows a schematic sketch.

First, there is light 9 traveling parallel to the first optical waveguide 6 having the bent portion 42a. This process consists of the first optical waveguide 6 and the light output optical waveguide end face 2 through which light is emitted or input.
The exposed portion of the first optical waveguide 6 is entirely parallel to the line segment j connecting the centers of 2° and 2°, where the surface 10 formed by cleavage or the like intersects the bent portion 42a of the first optical waveguide 6. Since the reflective end surface 42b is disposed, the optical energy of the light 9 is totally reflected at the total reflection end surface 42b, and the first optical waveguide 6 having the bent portion 42a is formed.
This is because it progresses against. The light 9 that has traveled in this manner becomes the output light 5 at the light output optical waveguide end face 2 of the first optical waveguide 6. A vertical light-emitting optical waveguide end surface 2 is formed so that the emitted light 5 is perpendicular to the first reference plane 4 formed by cleavage.

This light output optical waveguide end face 2 is formed by wet or dry etching.

Next, the second optical waveguide 3, which is an optical fiber, is placed in a position parallel to the first reference plane 4. The emitted light 5 is incident perpendicularly to the second reference plane 1 of the second optical waveguide 3 and travels inside the second optical waveguide 3 in parallel. Then, the direction of the output light 5 from the light output optical waveguide end face 2 is aligned with the first reference plane 4.
For example, Ga, I
n.

A sy P +- (λg = 1.55 μm) /
When applied to an example with an I n P active layer thickness of 0.15 μm,
The relationship established between the light 9 and the light output waveguide end face 2 is shown in FIGS. 3 and 4.

Below, as an example of forming a semiconductor optical device of the present invention, an example in which one total reflection end face 42b is provided will be described with reference to FIG.

(1) For example, an InP buffer layer 13 of the first conductive layer, Ga, In1-g A
A double hetero substrate in which a S y P I-y active layer 14 and a second conductivity type InP cladding layer 15 are successively grown is formed by epitaxial crystal growth.

(2) Mesa 16 tilted with respect to the cleavage plane 26 direction of the double hetero substrate, and mesa 16 tilted with respect to the cleavage plane 26
A mesa 16'' having an inclination opposite to that of
At the 6° intersection, the mesa stripes are shifted by the width of the groove 41 formed in step (5).

(3) A second conductivity type InP layer 17 and a first conductivity type InP layer 18 are sequentially buried and grown on the substrate on which the mesas 16 and 16'' are formed.

(4) Next, a dielectric layer 19 serving as an etching mask is deposited on the substrate on which the buried growth has been completed by plasma CVD or the like. After that, taking into account the mesa direction that will become the first optical waveguide 6 and the angle between the light output optical waveguide end face 2, a resist pattern 20 for forming a prismatic hole 40 including the light output optical waveguide end face 2 and the entire A resist pattern 20'' for forming a groove 41 including a reflective end surface 421) is formed.

Next, the process of forming the hole 40 is shown in FIG.
5 (A) to (F) in the cross section, and
The process of forming the groove 41 will be described below with reference to FIGS. 5(a) to 5(f) taken along the line B-B'' in FIG. 5(4).

(A), (a) The dielectric layer 19 on the substrate on which the buried growth has been completed is etched into resist patterns 20 and 20°. Thereafter, the electrode material 21 is applied to both the front and back surfaces of the substrate in accordance with the conductivity type of the double hetero substrate, for example, n-
AuGeNi for InP, Au for p-InP
(B), (b) Resist 20 where Zn is deposited respectively
and 20'' is dissolved with acetone or the like to lift off the electrode material on the pattern, and then subjected to heat treatment to form the electrode 22.

(C), (C) A dielectric layer 23 is again deposited on the substrate on which the electrode 22 is formed.

(D), (d) g After coating the resist 24 on the substrate on which the electric layer 23 is deposited, windows 43 and 43' are opened to match the 1/cyst patterns 2° and 20''.

(E), (e) Subsequently, the dielectric layer 23 is removed by etching using the resist 24 as a mask.

(F), (f) Using the unetched portion of the dielectric layer 23 as a mask, InP, Ga, In+-y A
Etching is performed on the S y P +-y crystal using a wet method or a dry method.

(5) From the previous steps (1) to (4), a substrate having grooves 41 and prismatic holes 40 is formed.

(6) The substrate is divided by cleaving or dicing so that the end face of the optical waveguide including the active layer coincides with the vertical portion of the prismatic hole 40, and the semiconductor optical device 25 according to the present invention is divided.
can be obtained.

(7) After die-bonding the semiconductor optical device 25 with the crystal cleavage plane 7 aligned with the end face of the human sink 12 such as diamond, wire bonding 28 to the semiconductor optical device 25 is sequentially performed to complete the SLD device system.

(8) - Ichiriki, SLA is semiconductor optical device 25
The overall length of the heat sink 12 is made to be approximately the same 2, and this is completed by placing it between the output fiber 29 and the input fiber 31.

The device system completed through these steps (7) and (8) functions by injecting positive or negative charges into the semiconductor optical device 25 through the wire bonding 28.
Unlike the conventional inclined waveguide element, the outgoing light to the optical fiber 29 and the incident light from the optical fiber 31, which correspond to a normal optical transmission path, are vertically incident. Therefore, even when a conventional semiconductor laser assembly process is applied, there is no mechanical interference between one end of the optical fiber and the end face of the element, and good optical coupling with a normal optical transmission path can be easily achieved.

Further, the amount of light emitted from the end face of the inclined waveguide element can be controlled by coating the end face of the inclined waveguide element with a low reflection film. In this case, there is no need for a low-reflection film whose thickness and composition are highly controlled; for example, a film with a light reflectance of several percent at the end face of the optical waveguide is sufficient. This is because the present waveguide structure essentially effectively suppresses laser oscillation due to the Fabry-Perot mode, and the improvement in the amount of emitted light reaches saturation even if the light reflectance is further reduced.

Moreover, light reflection through such an unoptimized low-reflection film has weak optical wavelength dependence (for example, IEICE technical research report 0QE84-93. pp, 29-p).
p, 3s Saito, Mukaiben, 3''-). Therefore, it goes without saying that one of the features of the inclined waveguide element, which is that the light reflection characteristics without wavelength dependence is less likely to be impaired, can be maintained.

(Second Embodiment) FIG. 6 shows a distributed feedback semiconductor laser (rDFB-
This D F
The internal structure of B-LD is illustrated so that it can be understood. DFB
-I and D are a region 31 and an opening grating in which a diffraction grating 32 for selecting light of a specific wavelength is carved in a guide layer provided along the active layer 14, with the total reflection surface 42b of the optical waveguide 6 as a boundary; It has a structure in which regions 44 that do not include 32 are combined. The diffraction grating 32 in this structure is built in when forming the double hetero substrate so as to diffract light in the direction of the optical waveguide, and the subsequent buried growth process is similar to the SLD and SLA in the first embodiment. are essentially the same.

It is known that in the DFB-LD, the phase of the diffraction grating 32 at the end face of the optical waveguide has a strong influence on the laser oscillation characteristics (for example, "InGaAsP/InPSes+").
1 conductor La5ers in 1.5μ
m Range +S, AKIBA, Presen
ted to Tokyo In5 position of
Techn.

1ogy, 1984), e.g.
x As, py / l n In P-based semiconductor lasers, the pitch of the first-order diffraction grating is as fine as 200 to 250 nm, so phase control of the diffraction grating in forming the end face of an optical waveguide by cleavage, etc. is currently almost impossible. It is possible.

Therefore, in order to stabilize the oscillation characteristics of this DFB-LD, it is necessary to suppress light reflection at the end face of the optical waveguide.

It is clear from the above description that the present invention is also effective in solving such problems.

At the same time, since the incident light and the outgoing light to the element are arranged in a straight line, if the gain and loss of the diffraction grating region are approximately balanced, SLA with wavelength selectivity can be achieved while using the conventional element system assembly process. You can also do that.

(Third Embodiment) FIG. 7 shows an example of application of the present invention in a case where the total reflection surface 42b has three or more odd-numbered force points. In this case, the length of the optical waveguide having optical gain increases as a whole while maintaining the advantage of easy coupling with an optical fiber in the present invention, so that the amplification gain of the SLA increases.

(Fourth Embodiment) In the first to third embodiments, an example was described in which the signal light incident on this element and the output light emitted from this element are opposed to each other. In the fourth embodiment, an example will be described in which the signal light incident on a second element and the output light emitted from this element are the same.

FIG. 9 is a diagram showing an example in which there is one total reflection surface 42b,
FIG. 10 is a diagram showing an example of an odd number of total reflection surfaces 42b having three or more force points. However, in this structure, it is simultaneously satisfied that θi is greater than or equal to the critical angle of total reflection at the total reflection surface 42b and that θn is less than or equal to the critical angle of total reflection at the end face 2 of the light output optical waveguide, and the output light 5 In order for the incident signal light 5' to be parallel or perpendicular to the first reference plane 4, the relationship between θi, θn, and θf is determined in the region shown by the curve in FIG.

Note that this relationship holds true for GaInA with an active layer thickness of 0.15 μm.
This is an example when applied to s (λg = 1.55 μm) / I n P.

All the structures of the first to fourth embodiments described here are based on the G a X I n H-x A
It is obvious that the present invention can be similarly applied to semiconductor optical devices other than sP H-y/I n P-based semiconductors.

〔Effect of the invention〕

As explained above, according to the semiconductor optical device of the present invention, the following effects can be obtained.

■After suppressing optical waveguide coupling reflectance, light can be emitted or entered parallel to or perpendicular to the reference plane.
Optical coupling can now be easily achieved between the semiconductor light emitting device and the optical fiber according to the present invention.

■ Light can be emitted at an easily adjustable angle, parallel or perpendicular to the reference plane of the semiconductor light emitting device. Therefore, the device can be easily aligned using a reference plane formed by a cleavage plane or the like other than the end face of the light-emitting optical waveguide, as in a normal semiconductor laser, and therefore manufacturing is easy.

■This reduction in the optical waveguide coupling reflectance has almost no wavelength dependence, unlike the effect of reducing the optical waveguide end face reflectance by a non-reflection film, and therefore, over a wide range of optical wavelengths,
Laser oscillation due to Fabry-Perot mode can be suppressed.

■Since the propagation direction of light changes on the total reflection surface, in the SLA element according to the present invention, the signal light that enters the element from one optical fiber and the amplified output light that exits from this element to the other optical fiber are separated. are aligned, which facilitates the manufacture of direct optical amplification systems incorporating SLA.

[Brief explanation of drawings]

FIG. 1 is an overhead view of the first embodiment of the semiconductor optical device of the present invention, FIG. 2 is a sketch diagram schematically showing the first embodiment of the semiconductor optical device of the present invention, and FIG. 1 is an enlarged view of the vicinity of the end face of the light emitting optical waveguide, FIG. 4 is a diagram illustrating the relationship established between the first optical waveguide and the end face of the light emitting optical waveguide, and FIG. 5 is a diagram showing the semiconductor optical waveguide of the present invention. A diagram showing the manufacturing process of the device, FIG. 6 is an overhead view of the second embodiment of the semiconductor optical device of the present invention, and FIG. 7 is an overhead view of the third embodiment of the semiconductor optical device of the present invention. , Figure 8 shows an example of the rate at which the incident light that enters the end face of the light output optical waveguide returns to the original first optical waveguide (optical waveguide coupling reflectance), based on the angle of inclination θn of the optical waveguide with respect to the end face shown in Figure 3. 9 and 10 are overhead views of the fourth embodiment of the semiconductor optical device of the present invention, and FIG. 11 shows the first optical waveguide and light output in the fourth embodiment. 12 is an overhead view of a conventional semiconductor optical device, and FIG. 13 is a diagram schematically showing a conventional semiconductor optical device. DESCRIPTION OF SYMBOLS 1... Second reference surface, 2... Light output optical waveguide end surface, 3... Second optical waveguide 4... First reference surface, 5... Outgoing light, 6... First optical waveguide, 9... light, 10... surface, 11... semiconductor substrate, 42a... bent portion, 42b...
- Totally reflective surface. Patent Applicant Anritsu Corporation Agent Patent Attorney Ryutabe Koike Fig. 12 Fig. 1 Fig. Fig. Fig. θf (degrees)

Claims (1)

[Claims] A semiconductor substrate (11) having a first reference surface (4);
According to Snell's law, the light (9) formed on the semiconductor substrate (11) and guided by the semiconductor substrate (11) emits light in a direction perpendicular or parallel to the first reference plane (4). a first optical waveguide (6) in which one end face (2) of the light output waveguide is arranged at an angle such that the light enters the waveguide; and the light output waveguide of the first optical waveguide (6). End face (2)
A second optical waveguide (1) into which the output light (5) emitted from 3), wherein the first optical waveguide (6) includes bent portions (42a) at odd numbers of places having total reflection surfaces (42b), and the total reflection surfaces (42b) A semiconductor optical device characterized in that it is arranged perpendicularly or parallel to a first reference plane (4).