JPH07114307B2 - Method of manufacturing optical functional element - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an optical functional device having an optical waveguide.

[0002]

2. Description of the Related Art A typical example of an optical functional element having an optical waveguide is a semiconductor laser. In particular, since it is a structure that easily obtains a low threshold value because carrier diffusion and recombination are blocked, There is a so-called buried structure semiconductor laser in which both sides of a waveguide (double hetero structure) are surrounded by a current block layer . Regarding the manufacturing method for obtaining the semiconductor laser structure such as this, for example, a conventional document 1:. J A
As seen in ppl. Phys. Vol.45, No.11, 1974, pp.4899, the so-called ridge structure is formed by etching the waveguide structure portion (which has a double hetero structure) including the active layer after uniform epitaxial growth. And then
There is a method of forming the buried layer / current blocking layer by re-growing once. Before that, normally, liquid phase epitaxy (LPE) was adopted twice for crystal growth, but since liquid crystal growth has problems in miniaturization of shape and mass productivity, metal organic chemical vapor deposition (MOCVD) method has been adopted. ) Was proposed. In contrast,
Further, as a method for producing an active layer and a buried layer only by a single or a series of crystal growths without the above-mentioned re-growth process, there is a conventional method 2: ELECTRONICS LETTER.
There is S 15th Vol.24, No.19, 1988, pp.1249 . In Re This, on the substrate formed in advance step, to form a double heterostructure and the current blocking layer in succession. That is, the difference in MOCVD growth rate due to the step of the growth surface and the crystal plane orientation is utilized.

[0003]

The object of the invention is to be Solved by the work described in the above literature 1
According to the manufacturing method, the end face of the double hetero structure formed in the ridge structure by etching is exposed to the atmosphere and oxidized, and interface defects are likely to occur.In particular, AlGaAs semiconductor lasers have problems in device performance and reliability. It was On the other hand, in the method disclosed in the above-mentioned Document 2, since the waveguide structure portion and the current blocking layer are formed by one-time crystal growth as described above, such a defect is solved, but instead of Such technical difficulties arise. a. It is necessary to control the positional relationship between the growth layer that grows from the substrate and becomes the buried layer and the growth layer on the ridge that has the double hetero structure very accurately. Therefore, the stripe width of the device (waveguide There are restrictions on the width and the element spacing in the case of integration. b. Since the growth layer from the substrate and the growth layer on the ridge have different crystal orientations, defects such as twins are likely to occur at the interface. c. Since the uneven shape formed on the substrate is easily deformed by the heat treatment process immediately before growth, it is difficult to form fine stripes (waveguide width).

Under these circumstances, the present inventor
In the process of reaching,
We tried to make a semiconductor laser. Explaining in order, first of all
As shown in FIG. 13, on the main surface of the n-GaAs substrate 2,
Thickness is 100 nm and width W _I and W _I are 10 μm by sputtering
Through 20 μm stripe-shaped insulating films 3 and 3
Recon nitride films (SiN _x ) 3 and 3 are formed. The pair
The main surface of the substrate 1 is exposed in the space between the edge films 3 and 3.
The window 4 which is the presented portion has a width W _W of 2 μm to 4
It has a linear stripe shape of μm. of course
Such a shape structure is formed in series on the main surface of the substrate 1.
The insulating film is etched according to the specified pattern.
It can be obtained by

Next, the cleanliness of the main surface of the substrate 1 is ensured.
Therefore, ashing is performed by oxygen plasma etching,
Oxide film removal with hydrochloric acid solution, shallow etching with phosphoric acid solution
After performing the etching, the known method MOCVD
Then, as shown in Fig. 14, strike according to the normal procedure.
Striped window sandwiched by the p-shaped insulating films 3 and 3
N-GaAs buffer layer 5 and n-AlGaAs clad on top of 4
The layer 6 and the GaAs waveguide layer 7 are formed. GaAs waveguide layer 7 is
Since we are finally aiming to build a laser, so-called laser
The active layer, which is also known as GaAs.
It may be a quantum well structure layer . Of this GaAs waveguide layer 7
On top of that, p-AlGa
The As clad layer 8 and the p-GaAs cap layer 9 are sequentially grown.
It

As a result, the side surfaces along the insulating films 3 and 3 are tilted.
A slanted, trapezoidal shape (ridge shape)
The substantial structural part of the
In the case of VD growth, the growth rate of the (1,1,1) B plane is (1,0,0)
Since it is slower than the surface,
Epitaxial layer with (1,1,1) B plane on the slope is formed
Because. On the other hand, on the other hand, the formation of the (1,1,1) B side
Long velocity itself progresses slowly at relatively high temperature growth
Therefore, as shown in FIG.
And by just forming the upper and lower clad layers 6 and 8,
The cladding layers are automatically formed on both sides of the GaAs waveguide layer 7 automatically.
The obtained results can be obtained, and the surroundings of the GaAs waveguide layer 7 can be obtained.
It is possible to obtain a desired embedded structure that is reasonably closed.

However, polycrystalline Al on the insulating films 3 and 3 on both sides
Growth of GaAs and formation of GaAs layer and cap layer on the side of the ridge
To suppress the length and obtain a shape that exactly matches the design shape
Is chlorine or hydrochloric acid during the above epitaxial growth.
It is effective to mix etching gas such as gas. Reverse
In general, the error on the striped window 4 is
The growth rate of the epitaxial layer depends on the epitaxial growth.
The area of the insulator within the surface diffusion distance of the material molecules for
Therefore, depending on the area concerned, one gas phase
Designing the in-plane distribution of growth film thickness and composition by growth
It will be possible. In this respect, according to the present invention, as described below,
When designing various optical functional devices,
And can be used to advantage.

However, as described above, the structure shown in FIG.
Once you have completed the steps,
As a whole, the SiN _x protective film 10 etc. is used as the entire protective layer by thermal CV
A part corresponding to above the GaAs waveguide layer 7 formed by D
After opening an opening in the protective layer 10, the p-electrode 11
By vapor deposition and then depositing the n-electrode 12 on the back surface of the substrate 2, the final
To obtain the desired embedded semiconductor laser 1
You can

[0009] A prototype embedded semiconductor device thus manufactured
Body laser 1 is not a very good characteristic but a standard characteristic
In other words, with an extremely simple manufacturing process
In spite of the existence, there are 10
It turns out that it has a minute function. In addition, the insulating films 3 and 3
Therefore, both sides of the striped window 4 are pre-insulated.
Necessary in the above-mentioned conventional documents 1 and 2 because
The current blocking layer was no longer necessary, so
Since it is simplified and the design conditions are relaxed, accuracy is also improved.
It was Furthermore, the growth on the insulating film 3 is as described above.
The use of etching gas and selection of various parameters
Since it is relatively easy to put it in a negligible amount,
For stripe width (element width or waveguide width) and element spacing,
The restrictions on the number of semiconductor
Even when arranging the z side by side, the degree of integration should be greatly increased.
Or the substrate is protected by the insulating film 3.
Therefore, there is little change in shape due to heat treatment process.
There was a fruit.

In particular, the GaAs waveguide layer (active layer) 7
If the GaAs quantum well structure is adopted, the characteristics will be even better.
GaAs substrate 2 can be obtained by using the InGaAs layer.
Absorption of the clad layers 6 and 8 itself
The thickness of the
It is not necessary to make it about 1.5 μm or more,
It becomes possible to make it thinner. The clad layers 6 and 8 are thin
Is low, that is, the height of the device is low.
This means that the width W _W of the tripe-shaped window 4 may be narrower.
However, in practice, it is possible to reduce it to 1 μm or less.

As described above, the present inventor has
Even if there is a certain area of the main surface of the substrate on the semiconductor substrate
After forming the insulating film leaving the exposed window, remove this insulating film.
Through the above-mentioned window by the vapor phase selective growth method used as a mask
At least the lower cladding layer and the waveguide on the exposed main surface of the substrate.
A lateral semiconductor laser in which a road layer and an upper cladding layer are sequentially formed.
To discover various advantages
It was However, in general, semiconductor lasers and
If you want to build an optical integrated circuit by combining
In terms of structure, it is possible to construct only an ordinary lateral semiconductor laser.
It is not good if it can be used, but other various optical functional devices
Is meaningless unless it can be manufactured with the same advantages. Starting
Ming was made in view of this point.

[0012]

In order to achieve the above-mentioned object, the present invention has, as a superordinate concept, (a) exposing a predetermined area of the main surface of a semiconductor substrate on the substrate.
After forming the insulating film leaving the window to
Exposed through the above window by the selective vapor phase growth method.
At least the lower cladding layer and the waveguide on the main surface of the substrate
Layer and upper clad layer are formed in order to fabricate an optical functional device
While using the method of
Species required to realize optical integrated circuits that perform various functions
This basic configuration is required as a method for manufacturing various optical functional devices.
One of the following configuration requirements (b) to (l) for the case (a)
We propose a manufacturing method of the added optical functional device. (b) The main surface of the substrate is the (1,0,0) surface, and the window is the
Form as a rectangular window whose direction is [0,1,1]
And the waveguide formed by the vapor phase selective growth
Forming a layer as a laser active layer along the longitudinal direction,
As a result, the optical functional element is cut along the longitudinal direction.
Inverted trapezoidal shape with the longitudinal end facing diagonally downward in the plane
The laser light emitted from the end of the active layer is
To obtain a vertical cavity surface emitting laser that is orthogonal to the principal plane of the plate.
When. (c) The lower clad layer and the upper clad layer are respectively
As a reflection layer with a multilayer structure,
It is formed as a well layer, and as a result, the optical function element is formed.
The opening on the upper surface of the upper clad layer directly to the main surface of the substrate.
To obtain a surface emitting laser that emits laser light above
When. (d) If the width of the window is narrowed at least once in the length direction,
When formed in a stripe shape that changes from wide to wide,
The waveguide layer formed by the vapor phase selective growth
Formed as a laser active layer along the length direction,
As the above-mentioned optical functional element, an active layer having a different propagation mode
Is a semiconductor laser united together in the above-mentioned length direction.
To get. (e) The main surface of the substrate is the (1,1,1) B surface, and the window is
Form as a rectangular window whose direction is [1,1, -2]
And the waveguide formed by the vapor phase selective growth
Forming a layer as a laser active layer along the longitudinal direction,
As a result, the optical functional element is cut along the longitudinal direction.
Surface, the edge of the active layer is perpendicular to the main surface of the substrate.
To obtain a semiconductor laser (f) The main surface of the substrate is the (1,0,0) surface, and the window is the
The direction of the rectangle is 45 ° to the cleavage plane of the semiconductor substrate.
It is formed so as to form a window, and by the above vapor phase selective growth,
Laser along the longitudinal direction of the waveguide layer formed by
It is formed as an active layer, whereby the optical functional element
The main surface of the substrate in a cross section along the longitudinal direction.
To obtain a semiconductor laser in which the edges of the active layer are vertical
thing. (g) The width of the above window changes periodically along the length direction.
In addition to forming into a stripe shape, the above vapor phase selective growth
The waveguide layer formed by
The optical functional element is formed as an active layer.
To obtain a distributed feedback semiconductor laser. (h) The windows run in parallel with the insulating film in between, but cross each other.
However, but in the middle of the length direction or at the ends,
Shaped into a pair of stripes that are close enough to be optically coupled
By forming the optical coupling element as the optical functional element.
Get a child. (i) The windows run in parallel with the insulating film in between, but cross each other.
No, but optically coupled to each other at lengthwise ends
Forming a pair of stripes that are close enough to each other
The waveguide layer formed by the vapor phase selective growth
Formed as a laser active layer along the length direction,
As the above-mentioned optical functional element, influence each other's output
Obtaining a semiconductor cross mode laser. (j) If the above window is formed as a closed ring-shaped window,
Both of the waveguide layers formed by the vapor phase selective growth
Is formed as the ring-shaped laser active layer, and
To obtain a ring type semiconductor laser as the optical functional element
thing. (k) Draw a loop from one end of the window above
Form a loop shape that returns to the other end that touches
The waveguide layer formed by phase selective growth
Is formed as a laser active layer,
As a functional element, a part of the loop is
To obtain the desired semiconductor laser. (l) Connect the above window to the linear first window and loop from one end.
Draw and return to the other end so that the one end and the other end are optically coupled.
It is composed of a second window that is close enough to the first window.
And a part of the second window is close enough that the comrades also optically couple with each other.
Contacted me.

[0013]

DETAILED DESCRIPTION FIG. 1, the lower cladding layer, the waveguide layer, at least having an optical waveguide structure portion formed an upper cladding layer, a first embodiment of the optical functional device made by the present invention
An example is shown. The reference numerals of the respective parts are already shown in FIG.
Regarding an example of manufacturing the lateral semiconductor laser 1 explained in accordance with
The same reference numerals are used, and the same reference numerals are the same or similar
Shows the components of.

In the reference fabrication example according to FIGS. 13 to 15,
Window 4 is a linear stripe pattern, as although both ends of the length direction were open at end edges corresponding substrate 1 as a rule, is shown in FIG. 1 (A), the substrate 1 The main aspect of
(1,0,0) , both ends of the window 4 in the longitudinal direction are insulating film portions 3 ,
As closed shape with 3 (i.e., the insulating film is in the Suyo such a rectangular frame shape in plan view), the position toward the longitudinal direction of the stripe-shaped windows 4 and [0, 1, 1], MOCVD By
Lower clad layer 6, Waveguide layer (laser active layer) 7, Upper side
If the clad layers are sequentially formed , as shown in FIG. 1 (B) , the longitudinal end is obliquely downward in the cross section along the longitudinal direction.
Inverted trapezoidal shape (both ends of the optical resonator are both facing down at 45 °)
End portions of the laser active layer 7
The laser light L _B emitted from the above is orthogonal to the main surface of the substrate 2.
It is possible to obtain a semiconductor laser directed to, that is, a kind of surface emitting laser 1.

On the other hand, the applicant of the present invention has already disclosed Japanese Patent Publication 1
-12114, in the central part surrounded by the dielectric,
We propose a surface emitting laser with a structure in which the GaAs active layer is protected by the AlGaAs layer by sequentially stacking the AlGaAs multilayer film, the GaAs active layer, and the AlGaAs multilayer film . Therefore, the idea of the present invention follow UTO can be obtained a surface emitting laser as well such structures. For example, as shown in FIG. 2 (A), to form a window 4 squares or the like on the main surface of the substrate 2 in a shape surrounded by the insulating film 3. The square shape is not essential, and may be a circular shape or another shape.

In this state, a lower reflective layer 13 as a lower clad layer having an AlGaAs multilayer structure which is grown by MOCVD while alternately and alternately changing the composition of aluminum, and a GaAs quantum well as the waveguide layer 7 in the present invention. Layer 7, and also Al grown with alternating aluminum composition
Upper reflective layer as upper cladding layer with GaAs multilayer structure
Forming fifteen . Also in this case, it is preferable to use an etching gas such as hydrochloric acid gas in order to suppress the growth on the side surface . Next
Then , the side surface is covered with the non-doped AlGaAs layer 16 , the hydrochloric acid gas is introduced together with the inducing metal to form the p-AlGaAs cap layer 9 only on the upper surface, and then the whole is made into an insulating film (silicon nitride film).
Cover with 8 and open the upper surface in a donut shape. here
If the electrodes 17 and 18 are formed after Zn diffusion, the result is shown in Fig. 2 (B).
As shown, it is possible to obtain a surface-emitting laser that conforms to the structure disclosed in the above publication.

[0017] However the present invention, the optical functional elements to obtain planar shape, eventually, especially focused can be determined <br/> considerably high precision by at least both sides the shape itself of the window 4 defined by the insulating film 3 ing. Therefore very fine laser, as well as can be constructed and composite resonator structure, the more generally the various optical integrated circuits. In particular , in the case of an epitaxial growth layer formed on the window 4, it is easy to obtain a structure in which the side surface is in contact with air or a dielectric, so that an optical waveguide having an excellent light confining function and being strong in bending can be obtained. The design flexibility is extremely high. From this point of view, examples for obtaining various optical functional elements will be described below.

First, as shown in FIG. 3 , the shape of a pair of insulating films 3 and 3 used as a growth mask is defined by a plane in which wide portions 31 , 31 and narrow portions 32 , 32 are continuous in the length direction. The window 4 has a striped shape as a whole.
There is Jo, but in so that is formed so as to move to the wide portion 42 on the way from the narrow portion 41 along its length. This
Then, as described above with reference to FIGS. 13 to 15,
Further , the MOC is formed on the main surface of the substrate opened by the window 4 according to the same process as in the first embodiment according to FIG.
When a semiconductor laser is manufactured by using VD, it is possible to obtain a semiconductor laser in which waveguides having different propagation modes are vertically coupled . According to the laser structure such as this,
As with the C ³ laser reported in Appl. Phys. Lett. Vol. 42, 1983, pp. 650, reflection occurs at the connection point of the two built-in waveguides, and therefore the cleavage plane at the connection point and both ends. It is possible to obtain the effect of stabilizing the oscillation wavelength by limiting the longitudinal mode that can be finally oscillated by utilizing that the oscillation condition is satisfied when the longitudinal modes of the two optical resonators composed of .

On the other hand, as shown in FIG.
1) On the plane B, a rectangular striped window 4 having a short side in the [ 1,1, -2 ] direction is formed by a rectangular frame-shaped insulating film 3, or a normal (1,0, 0) Approximately from the cleavage plane on the main surface of the substrate
When the window 4 is formed at an angle of 45 °, the laser emission end can be grown vertically with respect to the substrate rather than obliquely, so that an additional cleavage process or etching process is not performed thereafter . A semiconductor laser having a satisfactory optical resonator structure can be manufactured only by performing crystal growth once. In this case, since the emitting end is covered with the AlGaAs cladding layer, carrier recombination at the emitting end can be suppressed, and the effect of reducing the oscillation threshold and improving the laser output can be obtained.

Further, as shown in FIG. 5 , insulating films 3 and 3 are formed.
If the width is formed by a narrow portion 31 and a wide portion 32 periodically, and as a result, the wide portion 42 and the narrow portion 41 are periodically formed in the striped window 4, the laser structure is manufactured by the MOCVD described above. In that case, the width and thickness of the waveguide layer or the active layer 7 can be periodically changed. Therefore, if this period is set to an integral multiple of the guide wavelength of the semiconductor laser, a so-called distributed feedback type semiconductor laser can be manufactured by one selective growth. In FIG. 5, there is a wide portion slightly longer in the length direction at a portion slightly before the center point in the length direction, but a phase plate is to be manufactured here. By using such a phase plate, the oscillation wavelength can be stably matched to the Bragg frequency of the periodic structure, and the light output at both end faces can be made asymmetric, and the light output from one end face can be intentionally increased. And so on.

[0021] Figure 6, in accordance with the present invention, as the optical functional element
Shows a plan shape example of the stripe windows or insulating film when realizing the rectangular tropism coupler. The pair of stripe-shaped windows 4 and 4 running in parallel to each other are arranged so that the central portions 47 , 47 in the lengthwise direction thereof have a distance of the length L and are in close proximity to each other.
The plane shape of is determined. On this, already by the selective growth described, in the case of manufacturing a optical waveguide structure having a waveguide layer 7 put between them with at least the upper and lower cladding layers 6 and 8, respectively, to the A-A line in the Figure 6 The structure shown in FIG. 7 , which is a sectional view along the line, is obtained. The reference numerals of the corresponding parts in the above-described embodiments are used as the reference numerals of the respective parts. However, the electrode structure and the like are omitted, and only the basic structure portion is shown for simplicity.

[0022] However, in the insulating film 3, when the width of the insulating film portion 35 sandwiched in a portion both waveguides 7,7 is close below about 1～2Myu m, they both waveguides 7,7
Can be optically coupled. That is, when the propagation constants of the two waveguides 7 and 7 are the same, assuming that the coupling distance is L and the coupling constant is k, the electric field strength of the light propagating through one waveguide 7 is cos ( k. L) proportional to bond length L
The light can be branched at an arbitrary ratio by adjusting the . Et al is, in the coupling portion of the vicinity of the center as shown in FIG. 7, by forming the four-quadrant electrode right and left bisected, or vertically and horizontally, by changing the voltage bias conditions applied to them, the optical switch Can be realized. Of course, the principle itself of such an optical switch is already known.

FIG. 8 shows an insulating film pattern 3 for a cross mode laser in which two laser waveguides are coupled at both ends thereof. That is, the pair of parallel striped windows 4 and 4 have a narrow width between the insulating film portions 36 and 36 so that the portions 47 and 47 near both ends in the length direction are close to each other. , also the width is less about 1~2μ m. When an optical waveguide structure is produced on such a striped window by the procedure already described, the cross section along the line AA in the vicinity of the both end portions is the same as in FIG. 7 . Therefore, in FIG. 7 , the reference numeral 36 is also shown in parentheses. In such a structure, the coupling length L is designed so that the outputs from the two optical waveguides 7, 7 are equal at the emission end. Therefore, in a special case, the pair of parallel striped windows 4 and 4 may be close to each other with the insulating film portion 36 interposed therebetween over the entire length thereof. Furthermore, if the upper electrode is divided in the lateral direction and the two parallel lasers are driven independently, the intensity and phase of the laser output at the two emitting ends 47 , 47 change, so some information With this, the information can be detected as a near-field image or a far-field image.

The optical waveguide manufactured according to the present method is easy to intentionally cover the side surface with a dielectric material, and is otherwise surrounded by air, so that it has an essentially excellent light confining function. Becomes Therefore, as shown in FIG. 9 , when the stripe-shaped window 4 is formed, for example, in a ring shape (that is, when the pair of insulating films 3 and 3 are formed in a concentric shape), an optical waveguide structure is manufactured by the same procedure as above. did
In that case, a so-called ring laser can be obtained there. These lasers have no loss at the end face,
Since it is extremely small, it means that an optical resonator having a large Q factor is provided, and the half width of the emission light spectrum becomes extremely narrow. So, combining with a normal stripe laser,
It can be used to stabilize the wavelength or can be advantageously used as a local oscillator required in coherent optical communication.

Further, as shown in FIG. 10 , an end portion 4 which is on the substrate 2 and which has drawn a loop and has returned substantially after making one turn.
When the striped windows 4 of 8 and 48 are formed so as to face each other with the narrow insulating film portion 36 interposed therebetween, the laser outputs can all be emitted in the same direction without using an asymmetric mirror. it can. Further, if the narrow portion 36 is narrow enough to satisfy the above-mentioned coupling condition, a directional coupler can be configured here as well, and for example, an optical component oscillating while traveling clockwise in the orbiting direction and a left component Since it is possible to detect an interference pattern with an oscillating light component while traveling around, it is possible to realize a resonance type laser gyro. In the figure, in this end face portion, a cross section taken along line A-A will be the same as also shown in FIG.

[0026] Figure 11, Figure buried type semiconductor laser and that described with reference to FIG. 13 to 15 6, 7 or alternatively 10
An example of a suitable planar pattern of the insulating film 3 is shown when the directional coupler described in the above is manufactured in a combination relationship on the same substrate.

First, there is a linear striped window 4,
The middle portion 47 of the other stripe-shaped window 4 is close to the middle portion 47 in the lengthwise direction through the narrow insulating film portion 35 . The latter striped window 4 is the right arm portion 4R.
And the left arm portion 4L are formed into a loop shape, and both end portions 48 , 48 returning in a circle are opposed to each other with the narrow insulating film portion 36 interposed therebetween. Windows 49 and 49 for forming a waveguide type photodetector are formed at the ends of these portions, respectively. The width of the insulating film portion 37 between these portions 49 and 49 has a band gap. Wide to make it narrow. The laser, the directional coupler, and the waveguide type photodetector obtained by performing the above-described crystal growth based on such a mask pattern are provided with dedicated electrodes so that they can be independently driven.

An operation example of the optical integrated circuit thus obtained is
It can be described with reference to FIG. 12. Linear waveguide of semiconductor laser constituted by linear stripe window 4
A part of the light traveling in the direction indicated by the arrow R ₁ in 71 passes through the waveguide portions 81 1 and 81 of the directional coupler constituted by the pair of window portions 47 1 and 47 which run in parallel to each other. It is guided into the right arm 72 R of the loop line (arrow R ₂ ), and the rest is emitted from the emission end face toward the object 20 . The laser beam reflected by the object 20 is incident on the linear waveguide 71 again with a phase information φ corresponding to the distance between the emission end face and the object 20, in the figure, as indicated by the arrow L ₁ Traveling to the left in the waveguide, a part of which is guided through the waveguide portions 81 1 and 81 of the directional coupler into the left arm 72 L of the loop-shaped line as indicated by arrow L _2. After that, it interferes with the clockwise light component R ₂ via the waveguide portions 82 1 , 82 of the second directional coupler formed on both ends 48 1 , 48 of the window 4. Therefore, the left and right outputs of this directional coupler are detected by the waveguide type photodetectors 83 , 83 formed on the window portions 49 , 49 (FIG. 11 ). In effect, these photodetectors 83, 83 is obtained by applying a reverse bias to electrodes in a same structure as shown in FIG. 15. Therefore, the difference between the outputs of the pair of optical detectors 83, 83, for example, by detecting a differential amplifier 90, it is possible to obtain an output proportional to sin phi to the output of the differential amplifier 90, the interferometric displacement A difference meter can be realized . Your name, right arm 72 R
The interference condition can be optimized by adjusting the bias condition applied to each of the left arm 72L and the left arm 72L .

[0029]

According to the present invention, an optical waveguide structure having a waveguide layer sandwiched between upper and lower clad layers is provided.
Are common, but the groups described with reference to FIGS.
For semiconductor lasers with a typical horizontal structure (stripe shape)
It is not only limited to it, but it has a wide variety of specific functions,
Each of them can be used significantly in constructing a functional optical integrated circuit.
It is possible to fabricate various kinds of optical functional devices by a very simple series of selective vapor deposition . In other words, according to the invention
That the, relatively easy to build a different optical function of several on a single substrate, the degree of freedom in process of time, can take becomes high Ku freedom Mocha layout
It

[Brief description of drawings]

1 is a schematic diagram showing a 45 ° reflecting mirrored surface emitting laser as a first example of a fabricated Ru optical functional element according to the present invention.

FIG. 2 is a second example of an optical functional device manufactured according to the present invention .
FIG. 3 is a schematic configuration diagram showing a surface emitting laser as an example.

FIG. 3 shows two optical cavities coupled longitudinally according to the invention .
Of the window shape required to obtain a semiconductor laser
It is a figure.

FIG. 4 shows a laser emitting end with respect to a main surface of a substrate according to the present invention .
It is explanatory drawing regarding the window shape required in order to form vertically.

FIG. 5 shows a distributed feedback semiconductor laser according to the present invention .
It is explanatory drawing regarding the window shape required for.

FIG. 6 is an optical machine partially having a directional coupler according to the present invention .
Der explanatory diagram relating to a window shape necessary to produce the capacity element
It

FIG. 7 is a cross-sectional view taken along the line AA in FIG . 6 after the element is manufactured.
It

FIG. 8 shows the fabrication of a cross-mode semiconductor laser according to the present invention .
It is explanatory drawing regarding the window shape required in order.

FIG. 9 is required for making a ring laser according to the present invention .
It is explanatory drawing of a window shape.

FIG. 10 shows a configuration of a resonant laser gyro according to the present invention .
Explanatory drawing regarding the window shape necessary for obtaining the obtained semiconductor laser
Is.

FIG. 11 shows a configuration of a resonant laser gyro according to the present invention .
Explanatory drawing regarding the window shape necessary for obtaining the obtained semiconductor laser
Is.

FIG. 12 is manufactured according to the window shape shown in FIG .
It is explanatory drawing regarding operation | movement of an interference type displacement difference meter.

FIG. 13: MOCVD considered in the course of reaching the present invention
Fabrication of Striped Embedded Laser Diode
It is explanatory drawing regarding the window shape at the time of doing.

FIG. 14: MOCVD considered in the course of reaching the present invention
Of Striped Embedded Laser Diode by
It is a schematic block diagram in the near future.

15 is a strut completed through the process shown in FIG .
FIG. 2 is a schematic configuration diagram of an ip-shaped embedded semiconductor laser.
It

[Explanation of symbols]

1 semiconductors lasers, 2 substrate, 3 an insulating film, 4 a window to expose the substrate main surface, the lower cladding layer 6, 7 waveguide layer to the active layer or quantum well structure layer.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masahiko Mori 1-4-1, Umezono, Tsukuba-shi, Ibaraki Electronic Technology Research Institute, Industrial Technology Institute (72) Seiji Mukai 1-4-1, Umezono, Tsukuba-shi, Ibaraki (72) Inventor Hiroyoshi Yajima, 1-4 Umezono, Tsukuba City, Ibaraki Prefecture 72 Inventor, Electronic Technology Research Institute, Industrial Technology Institute (72) Inventor, Chen Chi-Yu, 1 Umezono, Tsukuba, Ibaraki Prefecture No. 4 Industrial Technology Research Institute, Industrial Technology Institute (56) Reference JP-A-4-105383 (JP, A)

Claims (11)

[Claims] 1. A predetermined area of a main surface of a substrate on a semiconductor substrate
After forming an insulating film leaving a window exposing the area,
Through the window by the vapor phase selective growth method using the film as a mask
At least the lower clad layer on the exposed main surface of the substrate ,
An optical functional element is formed by sequentially forming a waveguide layer and an upper clad layer.
A method of manufacturing ; the main surface of the substrate is a (1,0,0) surface, and the window is in the longitudinal direction.
If you form it so that it becomes a rectangular window with an orientation of [0,1,1]
To the waveguide layer formed by the vapor phase selective growth
Formed as a laser active layer along the longitudinal direction; thereby, as the optical functional element, along the longitudinal direction
Inverted trapezoidal shape with the longitudinal end diagonally downward in cross section
The laser light emitted from the end of the active layer is
To obtain a vertical cavity surface emitting laser that is orthogonal to the principal plane of the plate.
When; method for manufacturing a optical functional device according to claim. 2. A predetermined area of a main surface of a substrate on a semiconductor substrate.
After forming an insulating film leaving a window exposing the area,
Through the window by the vapor phase selective growth method using the film as a mask
At least the lower clad layer on the exposed main surface of the substrate,
An optical functional element is formed by sequentially forming a waveguide layer and an upper clad layer.
A method of manufacturing; the lower clad layer and the upper clad layer are multilayered, respectively.
Quantum well as a reflection layer by the structure and the above waveguide layer
Formed as a layer; whereby, as the optical functional element, the upper clad layer is formed.
From the opening formed on the upper surface, the laser is upwardly and orthogonal to the main surface of the substrate.
The method for manufacturing a optical functional device to said; to obtain a surface emitting laser that emits laser light. 3. A predetermined area of a main surface of a substrate on a semiconductor substrate
After forming an insulating film leaving a window exposing the area,
Through the window by the vapor phase selective growth method using the film as a mask
At least the lower clad layer on the exposed main surface of the substrate,
An optical functional element is formed by sequentially forming a waveguide layer and an upper clad layer.
A method of making the window, wherein the window is at least once in the length direction and the width is narrow.
And forming a stripe shape that varies Luo wide; above the waveguide layer formed by the vapor phase selective growth
Formed as a laser active layer along the length direction; thereby, the optical function element has different propagation modes
A semiconductor laser in which the active layers are integrally bonded in the length direction.
A method for manufacturing an optical functional device, comprising : obtaining a laser . 4. A predetermined area of the main surface of the substrate on a semiconductor substrate.
After forming an insulating film leaving a window exposing the area,
Through the window by the vapor phase selective growth method using the film as a mask
At least the lower clad layer on the exposed main surface of the substrate,
An optical functional element is formed by sequentially forming a waveguide layer and an upper clad layer.
A method of manufacturing; the main surface of the substrate is a (1,1,1) B surface, and the window is in the longitudinal direction.
If you form it so that it becomes a rectangular window with an orientation of [1,1, -2]
To the waveguide layer formed by the vapor phase selective growth
Formed as a laser active layer along the longitudinal direction; thereby, as the optical functional element, along the longitudinal direction
In the cross section, the edge of the active layer hangs down from the main surface of the substrate.
A method for manufacturing optical functional element characterized; to obtain directly since the semiconductor laser. 5. A predetermined area of a main surface of the substrate on a semiconductor substrate
After forming an insulating film leaving a window exposing the area,
Through the window by the vapor phase selective growth method using the film as a mask
At least the lower clad layer on the exposed main surface of the substrate,
An optical functional element is formed by sequentially forming a waveguide layer and an upper clad layer.
A method of manufacturing; the main surface of the substrate is a (1,0,0) surface, and the window is in the longitudinal direction.
Is a rectangular window that forms 45 ° with the cleavage plane of the semiconductor substrate
And the waveguide layer formed by the vapor phase selective growth as described above.
Formed as a laser active layer along the longitudinal direction; thereby, as the optical functional element, along the longitudinal direction
In the cross section, the edge of the active layer hangs down from the main surface of the substrate.
A method for manufacturing optical functional element characterized; to obtain directly since the semiconductor laser. 6. A semiconductor substrate having a predetermined area of a main surface of the substrate.
After forming an insulating film leaving a window exposing the area,
Through the window by the vapor phase selective growth method using the film as a mask
At least the lower clad layer on the exposed main surface of the substrate,
An optical functional element is formed by sequentially forming a waveguide layer and an upper clad layer.
A method of making the window ; the window having a width varying periodically along the length direction.
Forming into a lip shape; the waveguide layer formed by the vapor phase selective growth
It is formed as a laser active layer along the length direction, whereby a distributed feedback type semiconductor laser is formed as the optical functional element.
A method for manufacturing an optical functional device, comprising : obtaining a laser . 7. A predetermined area of a main surface of a substrate on a semiconductor substrate.
After forming an insulating film leaving a window exposing the area,
Through the window by the vapor phase selective growth method using the film as a mask
At least the lower clad layer on the exposed main surface of the substrate,
An optical functional element is formed by sequentially forming a waveguide layer and an upper clad layer.
A method of manufacturing; the windows run in parallel with the insulating film in between but cross each other
However, the light may not reach each other in the middle or at the end of the length direction.
Formed in a pair of stripes that are close enough to join
As a result, the above-mentioned optical function element is used as an optical coupling function element.
A method of manufacturing an optical functional device, comprising : 8. A predetermined area of the main surface of the substrate on a semiconductor substrate
After forming an insulating film leaving a window exposing the area,
Through the window by the vapor phase selective growth method using the film as a mask
At least the lower clad layer on the exposed main surface of the substrate,
An optical functional element is formed by sequentially forming a waveguide layer and an upper clad layer.
A method of manufacturing; the windows run in parallel with the insulating film in between but cross each other
However, as long as they are optically coupled to each other at the end in the length direction,
Is formed in a pair of stripe shapes that are sufficiently close to
To the waveguide layer formed by the vapor phase selective growth
It is formed as a laser active layer along the length direction; thereby, as the above-mentioned optical functional element, the mutual output is influenced.
Obtaining a semiconductor cross-mode laser to give: a method for manufacturing an optical functional device . 9. A predetermined area of a main surface of a substrate on a semiconductor substrate
After forming an insulating film leaving a window exposing the area,
Through the window by the vapor phase selective growth method using the film as a mask
At least the lower clad layer on the exposed main surface of the substrate,
An optical functional element is formed by sequentially forming a waveguide layer and an upper clad layer.
A method of making the same; forming the window as a closed ring-shaped window
The waveguide layer formed by the vapor phase selective growth
A ring-shaped semiconductor laser as the optical functional element.
A method of manufacturing an optical functional device, comprising : 10. A predetermined surface of a main surface of a substrate on a semiconductor substrate
After forming the insulating film leaving the window exposing the stack area,
Through the window by the vapor phase selective growth method using the edge film as a mask
At least the lower cladding on the exposed main surface of the substrate
Layer, waveguide layer, and upper cladding layer are formed in this order
A method of making a child; looping the window from one end thereof in close proximity to the one end
And forming the waveguide layer formed by the vapor phase selective growth into a loop shape returning to the other end.
Formed as a laser-active layer that draws a loop ;
The method for manufacturing a light functional element, characterized in; to obtain a semiconductor laser which has become laser light emitting end. 11. A predetermined surface of a main surface of a substrate on a semiconductor substrate.
After forming the insulating film leaving the window exposing the stack area,
Through the window by the vapor phase selective growth method using the edge film as a mask
At least the lower cladding on the exposed main surface of the substrate
Layer, waveguide layer, and upper cladding layer are formed in this order
A method of making a child; drawing the above window, a linear first window and a loop from one end
Enough to return to the other end and optically couple the one end with the other end.
And a second window in close proximity; and the first window and a portion of the second window also optically couple to each other.
A method of manufacturing an optical functional element, which is sufficiently close to the above .