JPH04179291A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To decrease an increment in the width of a spectral line when wavelength is variable by giving a stripe shape to an emission part, a phase control part and a wavelength selection part, reducing the width of an upper clad layer to the same width of an active layer and increasing the isolation resistance of each of the emission part, phase control part and wavelength selection part. CONSTITUTION:A emission part 120, a phase control part 130 and a wavelength selection part 140 are placed in a stripe shape in the direction of the laser resonator length on an n-InP substrate 110 having an n-InP buffer layer 110a, and an inverted mesa construction is given to the section in the direction orthogonal to the stripe direction. Also, the width of an upper clad layer 125 is made very small compared to the conventional one. Since this width is very small, the resistance of the upper clad layer 125 connecting each portion becomes higher than the conventional one. Moreover, a current block layer 160 has a semi-insulating InP layer 165, and the isolation resistance of the emission part 120, phase control part 130 and the wavelength selection part 140 becomes almost ten times as high as that of the conventional one. Thus, when the phase control part 130 is operated, the currents flowing from the phase control part 130 to the emission part 120 and the wavelength selection part are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a semiconductor laser whose oscillation wavelength is variable.

(Prior Art) In order to realize coherent communication, a semiconductor laser with a narrow Spoutle linewidth that allows tuning of the laser oscillation wavelength is required.

As a semiconductor laser having the former function)-C5 multi-electrode D
F B (Distributed Feedback)
k) Doped, multi-electrode DBR (Distribute
d Bragg Reflectnr) lasers are known. In either case, a light emitting section, a phase control section, and a wavelength selection section are provided in series on a compound semiconductor substrate of the first conductivity type (here, a light emitting section, a phase control section, and a wavelength selection section are provided in series) and the compound semiconductor substrate A current flock section made of a lattice-matched compound semiconductor layer is provided on the surface of each of the light emitting section, oscillation phase control section, and oscillation wavelength selection section. .

Below, documents related to the applicant of this application (Transactions of Institute of Electronics, Information and Communication Engineers, CI, Vol. J73 C=I, No. 5.
(1990, 5)), pp. 234-240) (The structure of a conventional oscillation wavelength tunable semiconductor laser and its manufacturing method will now be described.

FIGS. 4(A) to 4(E) are diagrams for explaining the structure, in which FIG. 4(A) is a perspective view schematically showing the entire semiconductor laser, and FIG. A cross-sectional view taken along the line P-P, (C) a plan view taken from the Q direction in (A), and (D) a cross-sectional view taken along the R-R line in (C). (E) is a cross-sectional view of the main part shown in Figure (C).
FIG. 8 is a sectional view of a main part taken along line 8. here,
(D) and (E) show the groove T in (A).

Only the 2nd and 3rd floor portions are shown. Note that grooves T1 and T2
Although not shown in the above-mentioned document, this groove (double channel) is provided to reduce the parasitic capacitance of the device.

In this semiconductor laser, a light emitting section 20, a phase control section 30, and a wavelength selection section 40 are provided in series on an n-I nP substrate 11 in this order.

The light emitting section 20 is composed of an InGaAsP (λ, = 1.5 um) active layer 21, an InGaAsP (λ 9 -] 53 um) light guide layer 23, and a p-InP upper cladding layer 25.

As shown in FIG. 4(B), the phase control section 30 is made of InGaAsP (λg=1.3) extending from the light emitting section 20.
um) Light guide layer 23 and p-InP upper urat layer 2
It consists of 5 parts.

As shown in FIG. 4(B), the wavelength selection section 40 includes a substrate 1, a crater 47 formed thereon, and a light emitting section 20.
, InGaAsP extending from the oscillation phase control section 30
(λg=1.3um) light guide layer 23 and p=InP
It consists of an upper lattice 25.

Then, the light emitting part 20 of the p-InP upper layer 25
, the p-■nGaAsP cositact layer 51 is formed on the portions that are the constituent components of the iu phase control section 30 and the wavelength selection section 40.
a, 51b, or 51c are provided, and furthermore, corresponding electrodes 53 for the light emitting section, electrodes 55 for the phase control section, and electrodes 57 for the wavelength selection section are provided on these contact layers.

In addition, this semiconductor laser is shown in Fig. 4 (△), (D),
(E) As shown in each, a light emitting layer 21 and a light guide layer 2
3 Each side and p-■nPJX side clat 2
A part of the side surface of 5 is a p-InP layer 61a from the substrate 1 side.
and an n-I nP layer 61bv. And p-I
The current blocking layer 61 of the nP upper cradle layer 25 (the part that is not filled in is the double channel grooves T1 and 1)
The structure was such that the upper side of the current protection layer 61 was covered with the same width as the dimension ρ between the two (see FIG. 4(A)). In addition, the fourth
In Figures (A), (D), and (E), 63 is an insulating film.

In addition, this semiconductor laser (well, it was manufactured by the method explained below. Figures 5 (△) to (F) are process diagrams for explaining the process, and show the main steps in the manufacturing process. FIG. 3 is a schematic perspective view showing the state of the element.

A crating 41 is formed by a known method only in the region of the n-I n P substrate 11 where the wavelength selection section 40 is to be formed (FIG. 5(A)).

Next, InG was added to the polymerization surface of this substrate by a known method.
aAsP (λg=1.5um) InGaAsP (λg=1.3um) which becomes part of the active layer 21 and the light guide layer 21
) anti-meltback layer 23a and p-InP layer 21a which becomes part of the p-InP upper client layer are formed in this order (FIG. 5B).

Next, on the platform where the light emitting part of the p-101 layer 21a is planned to be formed, 5
A SiO2 mask 7] of the layers 21a, 23a and 21 is formed by a known method and then removed by a known method until the uncovered portions of the substrate 11 are exposed. (FIG. 5(C)). In this etching, the crating 41 is preserved.

Next, while leaving the 5102 mask 71, the optical guide layer 23 is applied to the entire surface of the substrate 11, and the p-
An InP layer 25b is formed (FIG. 5(D)), and then
After the SiO2 mask 71 is removed, a p-InP crat layer 25c is formed while flattening the surface (FIG. 5(E)).

Next, a striped mask (
) is formed, then layers 25C225b, 2
The portions not covered by the striped masks 3 and 21 are removed up to the substrate 11 to form a mesa structure 73 (FIG. 5 ()). In the etching process for forming the mesa structure 73, the parts other than those under the mask are removed. The grating disappears during etching of the substrate portion.

Next, p-I
An nPi layer 61a and an n- and TnP layer 61b are formed in this order to form a current flock layer 61. Roughly, a p-InP layer 25d, which becomes a part of the p-InP upper lattice layer, is formed on the mesa structure 73 and the current blocking layer 61 to obtain a p-InP upper lattice layer 25, and this layer is further formed. A p-InGaAsP contact layer 51 is formed on the substrate 25 (FIG. 5(G)).

Thereafter, although not shown, a tuple channel is formed, an insulating film 63, and electrodes 53 to 57 are formed. Further, in order to separate the light emitting section 2o, the phase control section 30, and the wavelength selection section 40, predetermined portions of the contact layer 51 are removed to obtain the semiconductor laser shown in FIG. 4.

This semiconductor laser emits light when a current is passed through the light emitting section 20. This light is guided through the optical guide layer 23 and wavelength-selected by the wavelength selection section 40, so that it oscillates in a single mode. Furthermore, by passing a current through the phase control section 30, the refractive index of this portion was changed, so that the oscillation wavelength could be changed.

(Problem to be solved by the invention) However, in the conventional semiconductor laser, the light emitting part 20,
The phase control section 30 and the wavelength selection section 40 are connected by a p-InP upper cradle layer 25 having a width equal to the separation distance ρ (FIG. 4(A)) between the double channels T+ and 72. (Figure 4 (B)).

Since the impurity concentration of this p-I nP upper upper platform 25 is about 5X1017~Cm, the distance between the electrode 53 of the light emitting section 20 and the electrode 53 of the phase control section 30 is 20 am. The resistance of the crat layer portion between these electrodes is only about 1 to 2 ohms, and therefore the light emitting section 20, phase control section 30 and wavelength selection section 40
There was a problem in that the electrical isolation between each component was not sufficient.

In such a situation, the current injected into the light emitting section 20 will flow to the phase control section 30 and the wavelength selection section 40, so the emission spectrum line width will be the same as that without the phase control section 30 and the wavelength selection section 40. The ratio increases to 1. Further, when a current is passed through the phase control section 30 for wavelength tuning, this current flows into the light emitting section 20 and the wavelength selection section 40, respectively, thereby increasing the spectral linewidth. Specifically, when no current is passed through the phase control unit 30 (the spectral linewidth I increases by about 5 times), the spectral linewidth I is narrow enough to allow coherent communication within the variable wavelength range. However, it was hoped that this would be improved.

The present invention has been made in view of these points, and therefore, an object of the present invention is to provide a wavelength tunable semiconductor laser with high separation resistance of a light emitting section, a phase control section, and a wavelength selection section.

(Means for Solving the Problems) In order to achieve this object, the present invention provides a structure in which a light emitting section, a phase control section, and a wavelength selection section are provided in series on a first conductivity type compound semiconductor substrate. Roughly speaking, a current blocking section consisting of a compound semiconductor layer that lattice-matches with the aforementioned compound semiconductor substrate is provided to constrict the current, and between the aforementioned light emitting section, phase control section, and wavelength selection section. In a tunable oscillation wavelength semiconductor laser in which electrodes are individually provided on the surface, the light emitting section, phase control section, and wavelength selection section are arranged in stripes, and the current blocking section is provided one by one from the compound semiconductor substrate side. a laminate including a second conductivity type compound semiconductor layer, a first conductivity type compound semiconductor layer, and a semi-insulating compound semiconductor layer; It is characterized in that all sides of each are embedded with the above-mentioned current block portion.

In carrying out the present invention, it is preferable that the semi-insulating compound semiconductor layer described above be a compound semiconductor layer doped with a transition metal and having an electrical resistance of at least 10 5 Ωcm.

(Function) According to the structure of the present invention, since the light emitting section, the phase control section, and the wavelength selection section are formed into stripes, the width of the upper crat layer is the same as the width of the active layer, etc. narrows relative to the width of the upper crat layer. Therefore,
The resistance value due to the upper lattice layer between the light emitting section, the phase control section and the wavelength selection section increases by 0 compared to the conventional structure due to the reduction in the width thereof.

Roughly speaking, the current block portion is a laminate including a second conductivity type compound semiconductor layer, a first conductivity type compound semiconductor layer, and a semi-insulating compound semiconductor layer provided in this order from the compound semiconductor substrate side. Since all the sides of the above-mentioned light emitting section, oscillation phase control section and oscillation wavelength selection section are embedded in this current block section, the area other than the upper cladding layer between the light emitting section, phase control section and wavelength selection section is buried. The resistance value at that portion increases due to the provision of the semi-insulating compound semiconductor layer.

As a result, the separation resistance between the light emitting section, the phase control section, and the wavelength selection section is improved compared to the conventional one.

In addition, the current block portion is constituted by a laminate including a second conductivity type compound semiconductor layer, a first conductivity type compound semiconductor layer, and a semi-insulating compound semiconductor layer provided in this order from the compound semiconductor substrate side. Therefore, when the current block section is composed only of semi-insulating compound semiconductor layers, the current block section The electrical withstand voltage is improved.

(Embodiments) Hereinafter, embodiments of the semiconductor laser of the present invention will be explained with reference to the drawings. Note that each figure used in the explanation shows the size, shape, and arrangement of each component to the extent that this invention can be understood. The relationship is shown schematically (not too much), and each of the following examples is based on a compound semiconductor substrate of the first conductivity type.
Consisting of an InP substrate, the current block part is a p-InP layer,
This is an example constructed of a stacked body of an n-InP layer and an Fe (iron)-doped semi-insulating InP layer.

11-Sub-Example First, as the first example, the active layer is formed into a multiple quantum well structure 3a.
(Multiple Quantum Well: M
A tunable oscillation wavelength semiconductor laser having an active layer of OW) will be described.

<Structural explanation> Figures 1 (△) and (B) are diagrams for explaining the structure, where (A) is a perspective view of the main part, and (B) is the V-v line position of figure (A). (C) is a cross-sectional view taken along W-W in (A).
It is a sectional view at a line position.

Note that this is a double channel (not shown in the figure).

The semiconductor laser of the first embodiment includes a light emitting section 20, a phase control section 130, and a wavelength selection section 40 arranged in series on an n-InP substrate 10 having an n-InP buffer layer 110a.

In this case, the light emitting unit 120 is G a I n A s P
Layer/In Active layer 12 of MQW structure using nGaAs layer
1 and p = which is used as a protective layer for the active layer during the manufacture of this semiconductor laser and is structurally part of the upper crat layer.
It is composed of an InP layer 123 and an upper Clara 1 layer 125. Active layer] 2 GaI nAsPft
J, 'The thickness of InGaAs8 (well, the thickness is such that the desired oscillation wavelength can be obtained. In this case, the thickness of these layers is determined so that the oscillation wavelength is 1.55 um.Specific For example, the GaInAsP (λq
-1,3um) layer has a thickness of e.g. 130~20O
It is formed to be about A.

As shown in FIG. 1B, the phase control section 30 is made of GaInAsP (λ , -], 30m) Light guide layer] 31
and a p-InP upper cladding layer 125 extending from the light emitting section 120.

As shown in FIG. 1(8), the wavelength selection section 140 includes a grating 141 formed on the light guide layer 131 extending from the phase control section 130, the light guide layer 131, the light emitting section 120, It consists of a p-InP clay layer 125 extending from the oscillation phase control section 130.

Then, the light emitting section 120. Both the phase control section 130 and the wavelength selection section 140 are striped in the laser resonator length direction, and have an inverted mesa cross section orthogonal to the stripe direction. For this reason, the width L (see (Δ) in FIG. 1) of the upper cladding layer 125 is much smaller (about 21" m) than in the conventional case.

Roughly speaking, the light emitting part 120 of this upper crat layer 125,
Contact layers 15] are provided on portions corresponding to the phase control section 130 and the wavelength selection section 140, respectively.

Furthermore, p-InP layers 161 and n-I
A current blocking section 160 composed of an nP layer 163 and an Fe-doped semi-insulating InP layer]65 connects these light emitting sections]2
0, the phase control section 130 and the wavelength selection section 14.0 are provided so as to be buried on all sides thereof (including the sides of the contact layer 151). It is preferable that the InP layers [6] are provided on both sides of the active layer 121.

It is effective in reducing leakage current. By the way, the higher the resistivity of the e-doped semi-insulating layer 165, the better. However, the Fe-doped semi-thread color fastness In
The resistivity of the P layer is on the order of 107 Ωcm or the upper limit (for example, the literature of this applicant (Tenshi Tokyo No. 28 (1989), p. 74-77).In view of this, Fe-doped InP Layer ] 65 is doped with Feu so that the resistivity is at least 10 5 ΩCm or higher.

Further, on the contact layer] 51 and the current block section 160, a light emitting section 120. An insulating film 167 having a window exposing a part of the contact layer 151 of each of the phase control section 130 and the wavelength selection section 140 is provided, and the electrode 17 for the light emitting section], the electrode 173 for the phase control section, The wavelength selection part electrode 175 is connected to the corresponding contact layer 51.

In the semiconductor laser having this configuration, each of the light emitting section 120, the phase control section 130, and the wavelength selection section 140 has a width of p-InP.
Although the upper cladding layer 125 is connected, its width is very small (about 2 um, for example), so the resistance of the upper cladding layer 125 that connects each part is higher than in the conventional case. It includes a block layer 160 or a semi-insulating InP layer 165. Therefore, the separation resistance of each of the light emitting section 120, phase control section] 30, and wavelength selection section 140 is about 10 times that of the conventional case. Therefore, even when the phase control section 130 is operated, the degree of current flowing from the phase control section 130 to the light emitting section 120 and the wavelength selection section is reduced compared to the conventional case, so that the increase in the spectral width of the oscillation wavelength is reduced compared to the conventional method. I can hope that it will be able to be suppressed even more.

First, since the active layer has an MQW structure, the spectral width can be reduced more than when the active layer does not have an MQW structure.

Furthermore, although the example in FIG. 1 illustrates an ideal state, in reality, the width of the contact layer 151 is very narrow, so the insulating film 167 is placed on the sample so that only the contact layer 51 is exposed. It is difficult to form the insulating film 167, and the insulating film 167 is often formed so that the upper cladding layer 125 is slightly exposed. Therefore, the electrodes 171, 173, and 175 often come into contact with the upper crat layer 25. but,
Even if the electrode is in direct contact with the upper crat layer 125, this layer 12
Since 5 is semi-insulating, this also provides the advantage that the separation resistance does not decrease.

<Description of Manufacturing Method> Next, in order to deepen the understanding of the semiconductor laser of the first embodiment, an example of its manufacturing method will be described. Figure 2 (A)
~(J) shows the state of the device at the main steps in this manufacturing process, with (A)~(S) being a perspective view, and (F) ~
(J) is a process diagram shown with a sectional view taken at a position corresponding to the line X-X in (B). In this example, each semiconductor layer was grown using metallurgical vapor phase epitaxy (MOVP).
Method E).

First, an active layer 12 with an MQW structure consisting of an n-InP buffer layer 110a, a GaInAsP layer, and an InGaAs layer and a p-InP layer 1 are formed on an n-InP substrate 110.
23 is grown in this order (FIG. 2(A)).

Next, 5102 squares '7181 are formed only on the region of the p-InP layer 123 where the light emitting section is to be formed.

This mask 181 has a width Z of approximately 10 IJ m (direction parallel to the (011) direction of the InP substrate 110), and a (011
) The width Z2 in the direction parallel to the direction is approximately 300 LIm.

Next, the portions of the layers 123 and 121 that are not covered by the mask 5102 [8] are etched until the surface of the substrate 110 is exposed to form islands 183 (FIG. 2(B)).

Next, with the S I O2 mask 181 attached, the GaIn
The AsP (containing, = 1.3 um) light guide layer 131 is grown to the same height as the island-shaped body 183. 510
Since the GaIr+AsP layer 131 does not grow on the GaIr+AsP layer 131, the island-like body 183 is buried by the GaInAs1 layer 131 (FIG. 2(C)).

Next, a portion of the surface of the light guide layer 131 corresponding to the area where the wavelength selection portion is to be formed is coated with a crater by interference exposure method.
41 (FIG. 2(D)).

Next, after removing the 5102 mask 181 by a known etching method, a p-InP upper cladding layer 125 is roughly formed on the entire surface of the sample to a thickness of about 1.5 um.
A GaAsP contact layer 151 is sequentially grown to a thickness of about 0.5 um (FIG. 2(E)).

Next, a film 5102@185 is formed as an etching mask on the contact layer 151 (FIG. 2 (F)). ]1) It has a stripe shape extending from the formation region of the light emitting section, the phase control section, and the wavelength selection section to -C in the direction.

Next, a sulfuric acid-based etchant (for example, a mixture of 2S○4001202+H2O-411 (volume ratio)) (this is the mask 18 of the p-InGaAsP contact layer 751)
Remove the parts not covered by step 5. The sulfuric acid used was from Electronics Industrial Crate. Since this sulfuric acid-based etchant does not etch InP, etching in the depth direction is automatically stopped when it reaches the p-InP upper lattice layer 25 under the nGaΔSP contact layer 151. Ding the layer laterally (FIG. 2(G)). This etching is performed until the width Z4 of the contact layer 51 is approximately 2 um.

Next, use a hydrochloric acid-based etchant (for example, HCρ+H20=
f) The portions of the -InP upper substrate layer 125 that are not covered by the contact layer 15 are removed using a mixed solution of 4:1 (volume ratio). The hydrochloric acid used was from Electronics Industrial Crate. - When using the second etchant, p-I
nP crat layer] 25 is either the side surface or the main surface of the substrate 110 (
The etching is etched so that it is perpendicular to the contact layer, and the etching automatically stops when it reaches the active layer 121 (Fig. 2 (H)). 151 is approximately determined by the width Z4.

Next, as an etchant, bromomethanol (Br
The active layer 121 is edged using CH30H)). Since bromo-methanol exhibits an etching effect even on InP, active layer 121 and buffer layer 110a are etched. Therefore, each semiconductor layer 151.125.13], ]23.1 covered with the SiO2 film 185
21 and 110a have an inverted mesa shape (Fig. 2 (■)
)). Note that this etching is performed for a time such that the height of the inverted mesa portion 191 is approximately 2 to 2.5 um.

With such a height, it is possible to bury the inverted mesa portion 191 with the power block layer 7. This is because I can do things like J.

Next, p
-InP current blocking layer 16], n-InP current blocking layer 163, and Fe-doped InP layer 165 are grown in this order so that all sides of the reverse mesa portion 19 are covered with these layers 161.
．． 163 and ]O6 (FIG. 2(J)).

At this time, the optimum thickness of each layer 161, 163, 165 varies depending on the carrier density, for example, p-
The thickness of the InP layer 161 is 1 um, and the thickness of the n-InP layer 163 is 0.5 um.
The thickness of the Fe-doped InP layer 165 can be 1 nm or 1 nm.

Next, although not shown, tuple channels (T1, T in FIG.
Equivalent to 2. ) is formed, and then an insulating film 167 is formed.
, forming the electrode 151. Further, in order to separate the light emitting section 120, phase control section 130, and wavelength selection section 140, a predetermined portion of the contact 1 layer 51 is removed using a sulfuric acid-based etchant. As a result, the semiconductor laser of the first embodiment shown in FIG. 1 is obtained.

Next, a second embodiment will be explained using an example in which the present invention is applied to the semiconductor laser shown in FIG.

Figures 3 (c) and (B) are diagrams for explaining the same,
The (△) figure is a perspective view, and the (B) figure is the IJ-
It is a sectional view at the U line position. In addition, in these figures,
For the same constituent components as shown in Fig. 4,
The same reference numerals as 1 are used in the figure, and the same reference numerals as used in FIG. 1 are used to denote the same constituent components as those shown in FIG. 1.

In the semiconductor laser of this second embodiment, the upper crat layer and contour layer of the semiconductor laser shown in FIG.
A configuration in which a phase control section 230 and a wavelength selection section 240 are respectively configured, and a current block section 160 similar to that of the first embodiment is embedded in the entire side of each of the light emitting section 220, phase control section 230, and wavelength selection section 240. It becomes.

This semiconductor laser is manufactured in the process explained using FIG. 5(E).
Even the InGaAsP contact layer is grown, and the second
This can be done by forming a mesa-shaped stripe including the upper crat layer and contour layer by a method similar to that explained using FIGS. (F) to (J), and further forming a current block portion of 160%.

In the case of the semiconductor laser of this second embodiment, as in the case of the second embodiment, it can be expected that the fractional resistance will be about 10 times higher than that of the conventional structure.

Although the embodiments of the semiconductor laser of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, the following modifications can be made. The present invention can also be applied to the case of a DBR structure or a DFB structure.

Furthermore, although the It n -I n P substrate was used in the above embodiment, the same effects as in the embodiment can be obtained even when the substrate is a p-InP substrate and each semiconductor layer is of an opposite conductivity type.

Further, although the above-described embodiments have been described using an InP semiconductor laser as an example, the material constituting the semiconductor laser is not limited to this. For example, the present invention can also be applied to GaAs-based semiconductor lasers. In a GaAs-based laser, the semi-insulating compound semiconductor layer can be composed of, for example, a GaAs layer doped with cobalt, vanadium, or the like.

(Effects of the Invention) As is clear from the above explanation, according to the semiconductor laser of the present invention, the separation resistance of each of the light emitting section, phase control section, and wavelength selection section is higher than that of the conventional one. The extent to which current flows to the phase control section and the wavelength selection section can be reduced, and even when the phase control section is operated, the extent to which the current injected into the phase control section flows to the light emitting section can be reduced. Therefore, the increase in spectral line width during wavelength tuning can be reduced compared to the conventional method.

[Brief explanation of drawings]

Figures 1 (A) to (C) are diagrams for explaining the first embodiment, Figures 2 (A) to (J) are process diagrams for explaining the first embodiment, and Figure 3 ( A) and (8) are diagrams for explaining the second embodiment; G) is a process diagram for explaining the prior art. 11.110... First conductivity type compound semiconductor substrate (e.g. n-InP layer) 120.220... Light emitting section 130... Phase control section] 40... Wavelength selection section 160... Current flock section ]6]...Second conductivity type compound semiconductor layer]63...First conductivity type compound semiconductor layer]65...Semi-insulating compound semiconductor layer. Do1\ku□[Ctsu + 0 0 ('J C ri 1 1 11 飄(芒子／１＼Locoζ−〕゛−−′／−＼＼ Two consultation〆１＼ OnetoV 7%. 1 ÷ 8th ward defeat ~ 1 drop of a drop (Chin) dazzling 11 \ 1 ■ 0 ■ + C 2. Bandit?-\ == /1\ to 7 A11\ Otsu/1\ Shiro\no/”% Ichiko■ Ishibei Tsuribe; ;?)
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Claims (2)

[Claims] (1) A light emitting section, a phase control section, and a wavelength selection section are provided in series on a first conductivity type compound semiconductor substrate, and are lattice-matched with the compound semiconductor substrate in order to confine a current to these three sections. A tunable oscillation wavelength semiconductor laser is provided with a current blocking section made of a compound semiconductor layer, and electrodes are individually provided on the surfaces of each of the light emitting section, the phase control section, and the wavelength selection section. The control section and the wavelength selection section are formed into stripes, and the current blocking section is formed of a second conductivity type compound semiconductor layer, a first conductivity type compound semiconductor layer, and a semi-insulating compound provided in this order from the compound semiconductor substrate side. What is claimed is: 1. A semiconductor laser comprising a laminate including a semiconductor layer, wherein all sides of each of the light emitting section, the oscillation phase control section, and the oscillation wavelength selection section are embedded by the current block section. (2) The semiconductor laser according to claim 1, wherein the semi-insulating compound semiconductor layer is a compound semiconductor layer doped with a transition metal and having an electrical resistance of at least 10^5 Ωcm.