JP3336994B2 - Method of manufacturing semiconductor optical waveguide array and semiconductor optical device having array structure - 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 for manufacturing a semiconductor optical waveguide array and a semiconductor optical device having an array structure, and more particularly, to a semiconductor optical device having uniform optical device characteristics and greatly reducing the array size as compared with the prior art. The present invention relates to a method of manufacturing a reduced semiconductor optical waveguide array and an array-structured semiconductor optical device manufactured by the method.

[0002]

2. Description of the Related Art For practical use of a wavelength division multiplexing (WDM) optical communication system, it is indispensable to develop a technique for supplying a different wavelength light source or a wavelength selective light source which is a key device of the system at a low cost. . Above all, a wavelength selection light source capable of selecting an arbitrary oscillation wavelength on the user side of the system is one of the light sources that are strongly desired for practical use of the system because of its ease of use. As one mode of the wavelength selection light source, a plurality of different wavelength light sources having mutually different wavelengths is used.
Monolithic integration on a chip is considered, and as an example, a different wavelength semiconductor laser array is being developed.

One of the typical methods for fabricating a conventional different wavelength semiconductor laser array is described in IEE Electronics Letters V
ol. 28, no. 9, pp. 824-825 (hereinafter referred to as
Reference (1)).
In this method, first, a conventional metal organic chemical vapor deposition (MO)
An active layer such as a multiple quantum well (MQW) and an optical waveguide layer are grown on a wafer such as InP by VPE) or the like, and diffraction gratings having different periods are formed on the optical waveguide layer by an electron beam exposure method or the like. I do. After that, a current block structure is formed by high resistance embedding, etc., and each semiconductor laser constituting the array is processed by dry etching or the like to be electrically separated,
A different wavelength semiconductor laser array is formed. In this different wavelength semiconductor laser array, the semiconductor lasers constituting the array can be oscillated at different wavelengths, that is, at a wavelength corresponding to the Bragg wavelength of each diffraction grating, by the different periodic diffraction grating.

However, in this method, since the gain peak wavelength of the MQW active layer is constant in the array, the Bragg wavelength of the semiconductor laser determined by the period of the diffraction grating changes. However, there is a problem that laser characteristics such as light output during oscillation and threshold current are deteriorated, and it is not possible to obtain good laser characteristics from all the semiconductor lasers constituting the different wavelength semiconductor laser array. Was.

[0005] This problem can be solved by a method of manufacturing a different wavelength semiconductor laser array disclosed in JP-A-8-153928 (hereinafter referred to as Document (2)). This method is a method of using selective growth for growing an MQW active layer for generating a gain of a semiconductor laser. By using this method, the gain peak wavelength of the MQW active layer can always follow the oscillation wavelength of each semiconductor laser determined by the diffraction grating. Uniform and good laser characteristics such as threshold current and high output can be obtained.

As described above, in order to realize a different wavelength semiconductor laser array having good characteristics, 1) a technique of forming a different periodic diffraction grating for changing an oscillation wavelength;
2) It can be said that both techniques for making the gain peak wavelength of the MQW active layer follow the change of each Bragg wavelength of the different-period diffraction grating are necessary. From this point of view, the technology disclosed in the above-mentioned document (2), namely, 1) an electron beam exposure technology, and 2)
The manufacturing method combining the selective growth technology can be said to be a technology capable of satisfying two necessary conditions necessary for manufacturing a high-performance different wavelength semiconductor laser array.

However, an array-structured semiconductor optical device such as a semiconductor laser array of a different wavelength manufactured using the method of this document (2) has a fatal problem in supplying the device at low cost. That is, the size of the entire array-structured semiconductor optical device is increased. For example, when a different wavelength semiconductor laser array is manufactured by the manufacturing method described in the literature (2), the element spacing of each semiconductor laser constituting the array is 250 μm.
About. As a result, eight resonators having a resonator length of 300 μm (8
When a different wavelength semiconductor laser array is manufactured, the size of the entire array element is about 2 mm × 300 μm. This is because the selective growth technique disclosed in the literature (2) requires the use of dielectric masks each having a width of about 40 μm with each optical waveguide constituting the array interposed therebetween. To prevent the dielectric masks from affecting each other, at least 200 μm
This is because an array interval of about m or more is required. Therefore, in the method of manufacturing a different wavelength semiconductor laser array described in Document (2), the array interval cannot be essentially reduced.
For this reason, the yield of array elements from one wafer is 1/8 or less of the yield of one semiconductor laser, resulting in a remarkable increase in cost, and practical use of an array structure semiconductor optical element such as a different wavelength semiconductor laser array. Was a serious problem in doing so.

[0008]

As described above, according to the conventional methods for fabricating the different wavelength semiconductor laser arrays described in the literatures (1) and (2), 1) good and uniform semiconductor lasers constituting the array are obtained. In addition, characteristics cannot be obtained, and 2) the device size of the different wavelength semiconductor laser array increases, the yield from one wafer decreases, and the device cost increases significantly. Was.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a method for manufacturing a semiconductor optical waveguide array which enables miniaturization of an array size. In an array structure semiconductor optical device,
It is an object of the present invention to provide an array-structured semiconductor optical device comprising a miniaturized semiconductor optical waveguide array and having good and uniform characteristics.

The inventor of the present invention has repeated many experiments including Experimental Examples 1 to 3 to be described later to specify the width of the dielectric thin film, thereby minimizing the array size, and adjoining light guides constituting the array. It has been found that uniform optical element characteristics can be obtained by varying the composition and the layer thickness between the waveguides, and the present invention has been completed.

[0011]

In order to achieve the above object, a method of manufacturing a semiconductor optical waveguide array according to the present invention comprises a method of manufacturing a semiconductor optical waveguide array in a stripe-shaped growth region formed on a substrate by sandwiching the same with a dielectric thin film. A semiconductor multilayer structure having a quantum well layer,
Alternatively, in a method of manufacturing a semiconductor optical waveguide array including a plurality of optical waveguides formed by selectively crystal-growing a semiconductor multilayer structure including a bulk layer, a plurality of stripe-shaped growth regions extending in parallel are respectively formed. When a semiconductor multilayer structure formed between dielectric thin films and having a quantum well layer selectively in each growth region or a semiconductor multilayer structure composed of a bulk layer is crystal-grown by metal organic chemical vapor deposition, each of the growth regions Are formed in parallel at intervals shorter than the diffusion length of the raw material species in the reaction tube during crystal growth, and the width of the dielectric thin film provided between the respective growth regions is Wa,
The width Wm1 of the first outermost dielectric thin film and the width Wm2 of the second outermost dielectric thin film disposed outside the two outermost growth regions are Wm1> Wa and Wm2> Wa. Features.

According to a second aspect of the present invention, in the first aspect, the width Wm1 of the first outermost dielectric thin film and the width Wm2 of the second outermost dielectric thin film are set to Wm1 ≠ Wm2. The composition or the layer thickness of each semiconductor optical waveguide constituting the array is changed.

According to a third aspect of the present invention, in each of the first and second aspects, each region sandwiched between the plurality of growth regions is completely covered with a dielectric thin film. .

According to a fourth aspect of the present invention, in any one of the first to third aspects, an interval between adjacent ones of the plurality of growth regions is 50 μm or less.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, each of the plurality of growth regions has a width of 10 μm or less.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the number of the plurality of growth regions or the widths Wa, Wm1 and Wm2 of the dielectric thin film is provided.
Changing the composition or the layer thickness of each optical waveguide forming the array along the longitudinal direction of the growth region by changing at least one of them along the longitudinal direction of the growth region. It is characterized by.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, each interval between the plurality of growth regions is changed along a longitudinal direction of the growth region, thereby providing each of the plurality of growth regions. It is characterized in that the distance between the semiconductor optical waveguides is changed.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the width of each of the plurality of growth regions, the interval between each of the growth regions, and the width Wa, Wm of the dielectric thin film.
At least one of Wm2 and Wm2 is different between semiconductor optical waveguide arrays formed on a substrate.

According to a ninth aspect of the present invention, there is provided an array-structured semiconductor optical device according to any one of the first to eighth aspects.
It is characterized by being manufactured by.

According to a tenth aspect of the present invention, there is provided an array-structured semiconductor optical device comprising a semiconductor multilayer structure having a quantum well layer or a bulk layer in a stripe-shaped growth region formed on a substrate between dielectric thin films. the semiconductor multilayer structure MO made
In a semiconductor optical device provided with an optical waveguide formed by selective crystal growth by VPE vapor phase growth , the optical waveguides are arranged in an array at intervals shorter than the diffusion length of the raw material species in the reaction tube during crystal growth. The array of optical waveguides
The paths are grown collectively by the selective crystal growth.
Oh, wherein the Rukoto.

The invention of an array-structured semiconductor optical device according to an eleventh aspect is characterized in that, in the tenth aspect , the number of the arrayed optical waveguides is 16 or less.

According to a twelfth aspect of the present invention, in the tenth aspect of the present invention, the optical waveguide according to the twelfth aspect, wherein
It is characterized in that a plurality of these are arranged in an array at an interval of 0 μm or less.

According to a thirteenth aspect of the present invention, in the semiconductor device having an array structure according to the ninth to twelfth aspects, the width of the optical waveguide is 10 μm or less, and the side wall of the optical waveguide is formed by selective growth (111). It is a B crystal plane.

The invention array structure semiconductor optical device according to claim 14, in any one of claims 9 1 3 is selected from the selectively band-gap energy of the grown crystal, or the layer thickness At least one is different between adjacent optical waveguides.

The invention array structure semiconductor optical device according to claim 15, in any one of claims 9 1 4, wherein the array-shaped optical waveguide made of a semiconductor bulk active layer, the optical gain by current injection Characterized by having the function of an optical amplifier that causes

The invention array structure semiconductor optical device according to claim 16, in any one of claims 9 to 1 5, wherein the array optical waveguide, the multiple quantum well layer (M
QW), having a light reflection mechanism at both ends of the optical waveguide or near the optical waveguide, and causing laser oscillation by generating an optical gain by current injection.

The invention array structure semiconductor optical device according to claim 17, any one of claims 9 1 4, or 1 6 1
In the paragraph, the light reflection function is provided by a diffraction grating provided near the optical waveguide.

The invention array structure semiconductor optical device according to claim 18, in claim 1 7, wherein the different between optical waveguide period of the diffraction grating is adjacent.

The invention array structure semiconductor optical device according to claim 19, in any one of claims 9 1 8, the light spot size converter to at least one end of said arrayed optical waveguides Are integrated.

According to a twentieth aspect of the invention, there is provided an array-structured semiconductor optical device according to any one of the ninth to nineteenth aspects, wherein at least one end of the arrayed optical waveguide is provided with a star coupler and a multi-mode interferometer. (MMI, Multi Mode I
, at least one optical multiplexer selected from the group consisting of:

According to a twenty-first aspect of the invention, there is provided an array-structured semiconductor optical device according to any one of the ninth to twelfth or the fifteenth to eighteenth, wherein the array-structured semiconductor optical device has an oscillation wavelength of 970 to 990 nm. Is characterized in that it is a semiconductor laser array.

According to a twenty-second aspect of the present invention, there is provided an array-structured semiconductor optical device according to any one of the ninth to fourteenth or sixteenth to eighteenth aspects,
The semiconductor laser array has an oscillation wavelength of 1450 to 1510 nm.

According to a twenty-third aspect of the present invention, there is provided a compound resonator type multi-wavelength light source according to the fourteenth or fifteenth aspect, and a quartz-based Planer L having a diffraction grating formed thereon.
and an integrated ightwave circuit (PLC).

According to a twenty-fourth aspect of the present invention, there is provided an optical module light source, wherein at least one of the array-structured semiconductor optical elements according to any one of the ninth to twenty-third aspects is used. .

According to a twenty-fifth aspect of the present invention, there is provided the optical module according to the twenty-fourth aspect, further comprising: an optical element for substantially condensing light output from the semiconductor optical elements arranged in an array; It is characterized by taking out.

According to a twenty-sixth aspect of the present invention, there is provided an optical module according to any one of the ninth to twenty- first aspects, wherein at least an array-structured semiconductor optical device and an optical fiber for deriving an optical output from the array-structured semiconductor optical device. And a light receiving element for monitoring light output from the array-structured semiconductor optical element, wherein the array-structured semiconductor optical element is at least one array selected from the array-structured semiconductor optical element. A structure semiconductor optical device, wherein substantially all light emitted from the array structure semiconductor optical device is led out by the optical fiber.

According to a twenty-seventh aspect of the present invention, there is provided an optical module according to any one of the twenty-fourth to twenty-sixth aspects, wherein the wavelength filter for controlling the wavelength of light output from the semiconductor optical elements arranged in an array is provided. It is further characterized by having.

The optical communication system according to the present invention is defined in claim 9.
Or at least one of the array-structured semiconductor optical devices described in any one of ( 2 ) to (22) is used.

In the method of the present invention, SiO ₂ having dimensions and arrangement as shown in FIG. 1 is used as a mask for selective growth. FIG. 1 shows a mask for preventing SiO ₂ growth used in the selective growth of the present invention. SiO ₂ mask is a mask for selective growth, is formed on the InP substrate 99, sandwiching a stripe-shaped growth region 1 a plurality of, SiO ₂ having a width Wa
Mask 2, SiO ₂ mask 3 of the width Wm1, SiO of width Wm2
_It consists of _two masks 4. At this time, the width W of each growth region
0 is set to 1.5 μm. Hereinafter, the selective growth method of the present invention in which a crystal is selectively grown in an array-shaped growth region using a mask pattern as shown in FIG. 1 will be referred to as "narrow microarray selective growth" for simplicity. In the narrow-width microarray selective growth, multiple quantum wells are formed in a plurality of narrow (1.5 μm-wide) stripe-like selective growth regions 1 arranged at an arbitrary array interval shorter than the diffusion length of the source species during crystal growth. A crystal layer such as (MQW) is selectively grown.
The band gap wavelength of the crystal grown in each growth region 1 is basically the same as that of the SiO ₂ mask 3 disposed on the outermost side.
4 can be controlled by changing the widths Wm1 and Wm2. However, as described later, the width Wa of the SiO ₂ mask 2 is also a parameter that has a considerable influence on the composition and layer thickness of the crystal grown in the growth region.

Experimental Example 1 In Experimental Example 1, first, a narrow stripe width (1.5 μm width) was used.
The number of array-like growth regions 1 is 8 (8 channels),
Assuming that the array interval Λ = 11.5 μm, as shown in FIG.
1.50 μm composition compressive strain InGaAsP well / 1.2
A multiple quantum well (MQW) layer having a multilayer structure of a 0 μm-composition InGaAsP barrier is formed by metal organic chemical vapor deposition (MOV).
(PE). FIG. 2 shows a laminated structure of each channel. The growth conditions were a pressure of 150 Torr and a temperature of 6
50 ° C., the widths of the SiO ₂ masks 2, 3, and 4 were set to Wa = 10 μm and Wm1 = Wm2 = Wm, and the value of Wm was changed between 5 and 60 μm, and the photoluminescence (PL) of the MQW layer was changed. SiO ₂ mask width W at peak wavelength
The dependence on m was examined, and the results are shown in FIG. FIG.
S of photoluminescence (PL) peak wavelength of QW layer
i O ₂ and shows the mask width Wm dependent, channels on the horizontal axis number, and the vertical axis represents the photoluminescence (PL) peak wavelength of the MQW layer. As can be seen from FIG.
When Wm1 = Wm2, the wavelength distribution in the array is completely symmetrical in ch1 to ch8 around ch4 to ch5. The center value of the distribution of the PL peak wavelength in the channel can be changed from a short wavelength to a long wavelength over a wavelength range of 100 nm or more by increasing the width Wm of the SiO ₂ mask. However, almost uniform P in all channels
To obtain the L peak wavelength distribution, the mask width Wm must be equal to or somewhat wider than Wa.

Next, the dependence of the thickness of the optical waveguide layer on the mask width Wm was examined, and the results are shown in FIG. In FIG.
The horizontal axis represents the channel number, and the vertical axis represents the thickness of the optical waveguide layer. As can be seen from FIG. 4, the thickness of the optical waveguide layer increases as the width Wm of the SiO ₂ mask increases. The layer thickness distribution has almost the same distribution shape as the PL peak wavelength distribution in FIG. 3, and it has been found that the layer thickness of the optical waveguide layer can be controlled by changing the width Wm of the SiO ₂ mask.

Experimental Example 2 Next, as Experimental Example 2, the dependence of the PL peak wavelength on each channel when an asymmetric mask of Wm1 ≠ Wm2 was used was examined, and the results are shown in FIG. In FIG. 5, the horizontal axis represents the channel number, and the vertical axis represents the photoluminescence (PL) peak wavelength. As can be seen from FIG. 5, Wm1 = 10 μm
m, Wm2 = 70 μm, the PL peak wavelength between ch1 and ch8 in the array is substantially linearly increased by 1
It can be changed over a wavelength range of 100 nm from 480 to 1580 nm. Wm1 = 10 μm, Wm2 =
FIG. 6 shows a PL spectrum obtained when a 70 μm mask was used. In all channels, a strong PL intensity was maintained, and a sufficiently narrow PL half-width was obtained. In FIG. 6, the horizontal axis represents wavelength and the vertical axis represents intensity. On the other hand, as combinations of mask widths, Wm1 = 10 μm and Wm2 = 30
When μm is used, as shown in FIG.
The change rate of the PL peak wavelength between 8 can be made gentler. These results indicate that in the selective growth of the narrow-width microarray, the band gap of each MQW optical waveguide of the semiconductor optical waveguide array arranged at a very narrow interval can be appropriately selected by appropriately selecting a combination of the widths Wm1 and Wm2 of the SiO ₂ mask. This means that the wavelength can be arbitrarily controlled. As described above, it was confirmed that the narrow-width microarray selective growth technique of the present invention was extremely effective for controlling the band gap wavelength and the layer thickness of an array device having an extremely small interval.

Experimental Example 3 Finally, in Experimental Example 3, the effect of the width Wa of the SiO ₂ mask 2 disposed between the plurality of stripe-shaped growth regions on the crystal composition to be selectively grown was examined. The result is shown in FIG. In this experiment, an experiment was performed on an eight-channel array under the conditions that Wm1 + Wm2 + (7 × Wa) = 90 μm (constant) and Wm1 = Wm2 = Wm. That is, the experiment was performed under the condition that the integrated mask area is always constant. FIG. 7 shows that Wa = 2, 4, 6, 8,
10 μm (corresponding to array spacing Λ = 3.5, 5.5,
FIG. 7 shows the PL peak wavelength dependence of the MQW layer of each channel when it is changed to 7.5, 9.5, and 11.5 μm). When Wa = 2 μm (1/19 width of Wm)
Is that the wavelength distribution in the channel is convex downward, and Wa =
In the case of 4 μm (width of about ８ of Wm), the wavelength distribution becomes almost uniform in the channel, and in the case of Wa = 10 μm (the same width as Wm), the wavelength distribution has an upward convex shape. Was. This result is the result obtained in the experiment of FIG.
In order to obtain a substantially uniform PL peak wavelength distribution in all the channels in the array, the mask width Wm must be equal to or somewhat wider than Wa. "
Furthermore, as a new finding, in the case of Wm >> Wa, PL
It was found that the in-channel uniformity of the peak wavelength distribution deteriorated. From these, Wa is also the MQW in the array.
It was found that the parameter had a considerable effect on the bandgap wavelength control of the layer.

Finally, although not described with reference to the drawings, in the narrow-width microarray selective growth, the growth is performed by appropriately changing the width W0 (see FIG. 1) of the array-like growth region in the waveguide direction. The degree of freedom in controlling the band gap wavelength of the crystal can be increased. For example, in a portion where W0 is narrow, the thickness of the grown crystal is large, and the composition shifts to a longer wavelength side.

Based on the results of the above experimental examples, the narrow-width microarray selective growth of the present invention mainly uses two physical phenomena: 1) the diffusion effect of the source species, and 2) the migration effect of the source species. . The effect of 1) can be effectively used by setting the array interval of the microarray to be sufficiently shorter than the diffusion length of the raw material species (for example, an interval of 50 μm or less). It is possible to control the layer thickness with good uniformity. On the other hand, the effect 2) can be effectively used by setting the growth region width W0 of the microarray to be shorter than the migration length of the source species (for example, a width of 10 μm or less, a width of 1.5 μm, or the like). This improves the flatness of the crystal layer to be formed, and is advantageous in independently controlling the bandgap wavelength of each channel as shown in FIG.

Further, in the narrow-width microarray selective growth of the present invention, by selecting the growth region width W0 to about 1.5 μm, the arrayed optical waveguides formed by the selectively grown crystals are each single in the same size. Since the transverse mode condition is satisfied, the micro array optical waveguide can be formed 1) without etching the semiconductor, so that the yield can be remarkably improved. 2) As shown in FIG. Becomes a smooth (111) B surface,
Compared to the conventional optical waveguide having uneven side surfaces formed by etching, it also has an advantage that an arrayed optical waveguide with extremely low loss of an optical signal can be formed.

The above experimental results indicate that the use of the narrow-width microarray selective growth technique of the present invention allows an array to be formed in a region of a size in which one light source was conventionally produced at 250 μm intervals. This means that it is possible to form an array light source of different wavelengths whose crystal composition is appropriately controlled between the constituent optical waveguides with a very high integration. As a specific example, even a different wavelength 8ch array light source having a cavity length of 300 μm can be manufactured in a conventional one chip size (250 μm × 300 μm), and the same number of chips as a conventional single optical element This means that the "array-structured semiconductor optical device" can be manufactured on one wafer. That is, the degree of integration of the conventional integrated optical device can be increased to 10 times or more, and the present invention is a very effective technique for realizing a semiconductor optical device having an ultra-highly integrated array structure.

[0048]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Embodiments Embodiments of a method for manufacturing a semiconductor optical waveguide array and an array-structured semiconductor optical device according to the present invention will be described. In the present invention, when a semiconductor optical waveguide array is crystal-grown by selective growth using a metalorganic vapor phase epitaxy method using a dielectric mask, a plurality of semiconductor optical waveguide arrays are formed in parallel at an interval shorter than the diffusion length of the raw material species in the reaction tube. Between the optical waveguides adjacent to the semiconductor optical waveguide thus formed, a dielectric thin film having a width Wa formed between the respective growth regions and widths Wm1 and Wm2 (Wm2) formed on the outermost sides.
1. The band gap energy and the layer thickness of the crystal to be grown are controlled using a dielectric thin film of Wm2> Wa).

[0049]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the accompanying drawings. Example 1 This example is an embodiment in which the semiconductor optical device having an array structure according to the present invention is applied to a microarray distributed feedback (DFB) type semiconductor laser. FIG. 8 is a layout diagram of a diffraction grating,
FIG. 9 is a plan view of the mask, and FIG. 10 is a cross-sectional view showing a semiconductor laser layer structure of each channel of the array. The microarray distributed feedback (DFB) type semiconductor laser (hereinafter simply referred to as “semiconductor laser”) 100 of this embodiment has a detuning (difference between the gain peak wavelength of the laser and the Bragg wavelength of the diffraction grating) of an appropriate value (± 10 nm). ) Controlled microarray distributed feedback (DFB) type semiconductor laser. That is, as shown in FIG. 10, the semiconductor laser 100 has an emission wavelength (hereinafter, omitted) on an n-InP substrate 99.
N-InGaAsP semiconductor layer 11 having a composition of 1.13 μm,
n-InP spacer layer 12, n-I having a composition of 1.20 μm
nGaAsP light confinement layer 13, 7-layer multiple quantum well (M
QW) layer 14 (1.50 μm composition compressively strained InGaAsP)
(Well / composed of 1.20 μm InGaAsP barrier), 1.20 μm composition InGaAsP light confinement layer 15 and p-InP layer 16. Further, the semiconductor laser 100 has a p-InP buried cladding layer 17 having a layer thickness of 2.0 μm, a p ⁺ -InGaAs contact layer 18 having a layer thickness of 0.3 μm, and a SiO ₂ protective film 19 on the laminated structure. Further, a Cr / Au upper electrode 20 and a Cr / Au lower electrode 21 are provided.

Next, a method for fabricating the semiconductor laser 100 will be described with reference to FIG.
A method for manufacturing the semiconductor laser 100 will be described with reference to FIGS. First, as shown in FIG.
A diffraction grating pattern 88 is drawn by using an electron beam exposure method or the like in an area of eight channels, each of which has a width of 5 μm and a length of 300 μm per channel, which is arranged at a horizontal interval of 11.5 μm on the substrate 9. At this time, in order to change the oscillation wavelength of each channel to 1536 to 1568 nm in all eight channels (set to different oscillation wavelengths by 4 nm between adjacent channels), the period Λ1 of the diffraction grating of channel 1 is set to 240 nm, and sequentially. 0.625 nm period
And the period Λ8 of the diffraction grating of the channel 8 is 2
It is set to 45 nm. This diffraction grating pattern 88
Is transferred onto an n-InP substrate 99 by ordinary wet etching or the like to form a diffraction grating 88 having a depth of 60 nm.

Next, the substrate 99 on which the diffraction grating 88 is formed
As shown in FIG. 9, SiO ₂ masks 2, 3, and 4 for selective growth are formed in the <011> direction. At this time,
The mask widths are Wa = 10 μm, Wm1 = 20 μm, W
m2 = 50 μm, and the mask has eight growth regions (that is, in the region of the diffraction grating 88, each growth region width W0 = 1.5 μm).
m) so as to face each other. On the other hand, in order to introduce a window structure at both end faces of the resonator, a 25 μm wide SiO
_{(2) The} masks 5 are arranged at both end positions of the resonator. This Si
On the substrate on which the O ₂ masks 2, 3, 4, 5 are formed, FIG.
0, the n-InGaAsP semiconductor layer 11 having a composition of 1.13 μm, the n-InP spacer layer 12, and the n-InGaAsP optical confinement layer 13 having a composition of 1.20 μm have a composition of each semiconductor layer in the laminating direction shown in the cross-sectional view of FIG. , 7-layer multiple quantum well (MQW) layer 14 (1.50 μm composition compressively strained InGa)
(AsP well / composed of 1.20 μm InGaAsP barrier), 1.20 μm InGaAsP optical confinement layer 15 and p-InP layer 16 are selectively grown by metal organic chemical vapor deposition (MOVPE) or the like. The growth conditions are
The pressure is 150 Torr and the temperature is 650 ° C. At this time, MQW
The photoluminescence (PL) peak wavelength of layer 14 is
Channels 1 to 8 could be changed to 1535 to 1570 nm. As a result, the gain peak wavelength of the MQW layer 14 can be changed by following the oscillation wavelength of each channel determined by the period Λ of the diffraction grating, and the amount of detuning of each channel (difference between the oscillation wavelength and the gain peak wavelength) Was always maintained at a good value of ± 10 nm or less.

After each semiconductor layer is formed in this manner, the mask opening width W0 of the growth blocking mask is formed again from 1.5 μm to 5 μm in the entire region. A 0.0 μm p-InP buried cladding layer 17 and a 0.3 μm-thick p ⁺ -InGaAs contact layer 18 are selectively grown by MOVPE. afterwards,
An SiO ₂ film is formed on the entire surface, a current injection window is formed, and C
An r / Au upper electrode 20 and a Cr / Au lower electrode 21 are formed by a normal sputtering method or the like. Finally, the resonator is cleaved at 350 μm so that a window structure having a length of 25 μm is disposed on both end surfaces of the resonator, and a low reflection coating made of a SiON film is formed on both end surfaces by a normal sputtering method or the like to form an element. Completed.

Thus, a different-wavelength DFB laser array in which the detuning of each DFB laser constituting the array is independently controlled while the chip size of the entire array is as small as about 100 μm × 350 μm is realized. We were able to. Since the detuning amount of each channel is appropriately controlled, the CW threshold current is 10 mA ± 1 m for all channels at 25 ° C.
A, good and uniform characteristics of 18 mW ± 1 mW / 150 mA on one side were obtained.

Embodiment 2 This embodiment is an embodiment in which the semiconductor optical device having an array structure according to the present invention is applied to a microarray different wavelength semiconductor laser with a spot size converter. FIG. 11 is a plan view of a mask, FIG. 12 is a diagram showing the composition of each semiconductor layer in a stacked structure, and FIG. 13 is a partial cross-sectional perspective view showing the structure of a semiconductor laser. The semiconductor laser 200 of this embodiment is a microarray different wavelength semiconductor laser equipped with a spot size converter ( Spot Size Converter, SSC), and each channel has a layered structure having a layer composition shown in FIG. Is provided. The semiconductor laser device structure of each channel is the same as the device structure of Example 1 except that the thickness of the p-InP buried cladding layer 17 is 5.0 μm.

First, as shown in FIG. 11, a semiconductor laser 200 is formed on an n-InP substrate 99.
Selective growth SiO ₂ masks 2, 3, and 4 are formed in the <011> direction using a stepper or the like. SiO ₂ mask 2,
Nos. 3 and 4 are arranged at an array interval of 20 .mu.m across eight array-shaped growth regions each having an opening width W0 = 1.5 .mu.m.
At this time, in the laser region having a region length of 400 μm, SiO 2
₂ of the mask 2 width Wa1 = 18.5μm, SiO ₂ mask 3
Width Wm1 = 30 μm, width Wm2 of SiO ₂ mask 4 = 70 μm
μm, and in the SSC region having a region length of 200 μm, SiO
₂ The width Wa2 of the mask 2 is 4 μm, and the width Wm3 of the SiO ₂ masks 3 and 4 is 7 μm. However, in the SSC region, SiO
₂ The width of the mask 2 is Wa2 = 4 μm, and the array interval is 20 μm.
Since it is smaller than μm, a dummy growth region 77 exists between the growth regions of the respective channels.

On the substrate on which this mask is formed, FIG.
An optical waveguide layer as shown in FIG.
Selective growth under conditions of a pressure of 70 torr and a temperature of 650 ° C. by PE) or the like. More specifically, the laminated structure includes:
N-InGaAsP semiconductor layer 11 having a composition of 13 μm, n-
InP spacer layer 12, n-InG having a composition of 1.20 μm
aAsP light confinement layer 13, 1.50 μm composition compressive strain I
nGaAsP well / 1.20 μm composition InGaAsP
A seven-layer multiple quantum well (MQW) layer 14 comprising a barrier,
1. an InGaAsP light confinement layer 15 having a composition of 20 μm;
And the p-InP layer 16. As a result of the growth, the total thickness of the optical waveguide layer is 0.2 in channels 1 to 8 in the laser region.
The distribution was in the range of 5 to 0.35 μm, and in the SSC region, the distribution was 0.08 to 0.1 μm in channels 1 to 8. The peak wavelength of the photoluminescence (PL) of the MQW layer in the laser region is 1540 for channels 1 to 8.
１５1590 nm. After each of the semiconductor layers 11 to 16 is grown in this manner, the mask opening width W0 of the growth-inhibiting mask is increased from 1.5 .mu.m to 12 in all regions.
Using the mask, a p-InP buried cladding layer 17 having a thickness of 5.0 μm and ap ⁺ -InGaAs contact layer 18 having a thickness of 0.3 μm are grown by MOVPE using this mask. Thereafter, an SiO ₂ film 19 is formed on the entire surface, a window for current injection is formed, and a Cr / Au upper p-electrode 20 and a Cr / Au lower n-electrode 21 are formed by a normal sputtering method or the like. Finally, laser region length 400μ
Then, the entire cavity length was cleaved at 600 μm so as to have a SSC region length of 200 μm, and a high-reflection coating film 22 made of a SiON film was formed on the laser-side end face by a normal sputtering method or the like, and the device was completed.

In this manner, an 8-channel different wavelength semiconductor laser array with a spot size converter having an extremely small chip size of 160 μm × 600 μm as a whole array was realized. The laser array has an oscillation wavelength of 1540 to 1590n in all channels.
m and a threshold current of 6 m
A ± 1 mA, showing very uniform and good characteristics, 25
An excellent value of 30 mW or more was obtained for the one-sided optical output at 30 ° C. As a result of measuring the coupling loss with the flat-end optical fiber, it was possible to obtain an extremely good value of 3 dB or less for all channels, and it was confirmed that the spot size converter was functioning properly for all elements constituting the array. Was done.

Embodiment 3 This embodiment is an embodiment in which the semiconductor optical device having an array structure according to the present invention is applied to a microarray semiconductor optical amplifier with a spot size converter. FIG. 14 is a plan view of the mask, and FIG.
FIG. 5 is a diagram showing the composition of each semiconductor layer of the laminated structure, and FIG.
1 is a partial sectional perspective view showing a structure of a semiconductor laser. The optical amplifier 300 of this embodiment is a microarray semiconductor optical amplifier with a spot size converter. Each channel of the optical amplifier has a layered structure having a layer composition shown in FIG. 15, and has an overall configuration shown in FIG. It has. That is, as shown in FIGS. 15 and 16, n-In
On a P substrate 99, an n-InP buffer layer 24 having a thickness of 0.2 μm and a compressive strain In having a composition of 1.50 μm having a thickness of 0.4 μm are formed.
The laminated structure of the GaAsP bulk active layer 25 and the p-InP layer 16 is provided. On the laminated structure, the p-InP buried cladding layer 17 (layer thickness: 5.0 μm), p ⁺ -InGaAs
It has a contact layer 18 (layer thickness 0.3 μm). Furthermore,
The optical amplifier 300 includes an SiO ₂ protective film 19 on the entire surface of the substrate, and has a Cr / Au upper electrode 20 and a Cr / Au lower electrode 21 on the upper and lower sides. In the semiconductor laser 200 of the second embodiment as described above, the width W0 of the growth region of the SiO ₂ mask used in the selective growth of the narrow microarray is set to W0 = 1.5 μm.
And MQW was used for the active layer. On the other hand, in this embodiment, the growth region width W0 is set to W0 = 0.6 μm, and the InGaAsP bulk layer is used for the active layer. A microarray semiconductor optical amplifier can be realized.

First, as shown in FIG. 14, an optical amplifier 300 is formed on an n-InP substrate
In the <011> direction, SiO ₂ masks 2, 3, and 4 are formed at an array interval of 20 μm. At this time, the width of the SiO ₂ mask is Wa2 = 1 μm in the SSC region having a region length of 300 μm.
, Wm3 = 4 μm, and in an amplifier region having a region length of 800 μm, Wa1 = 18.5 μm, Wm1 = 80 μm, and Wm2 = 80
.mu.m, and a mask is formed in each region so as to face each other across eight growth regions (each growth region width W0 = 0.6 .mu.m). However, in the SSC region, the width of the SiO ₂ mask 2 is Wa2 = 1 μm, which is smaller than the array interval of 20 μm.
7 are present. On the other hand, in order to introduce a window structure to both end faces of the resonator, a SiO ₂ mask 5 having a width of 25 μm is arranged at the end face position of the resonator.

On the substrate on which this mask has been formed, FIG.
To form a laminated structure having a layer composition as shown in FIG. Specifically, the n-InP buffer layer 24 having a thickness of 0.2 μm,
0.4 μm thick 1.50 μm compositional compressive strained InGaAs
The P bulk active layer 25 and the p-InP layer 16 are selectively grown by metal organic chemical vapor deposition (MOVPE) or the like. The growth conditions are a pressure of 300 Torr and a temperature of 650 ° C. At this time, the photoluminescence (P
L) The peak wavelength is 1550-1 for channels 1-8
It could be kept almost constant at 570 nm. Also, SS
The PL peak wavelength of the bulk layer in the C region is channel 1 to channel 1.
8, the wavelength could be made sufficiently short as a low-loss passive waveguide having a uniform size of 1380 to 1390 nm and a spot size conversion function. InG in amplifier area
For the thickness of the aAsP bulk layer, the InG in the SSC region
The thickness of the aAsP bulk layer was reduced to 1/4 or less in all channels.

After forming each semiconductor layer in this way, the mask opening width W0 of the SiO ₂ masks 2 to 4 is set to 0.6.
.mu.m to 12 .mu.m in the entire region. Using this mask, the p-InP buried cladding layer 17 is formed.
A p ⁺ -InGaAs contact layer 18 (layer thickness 0.3 μm) is grown by MOVPE (layer thickness 5.0 μm).
Thereafter, a SiO ₂ film 19 is formed on the entire surface, a current injection window is formed, and a Cr / Au upper electrode 20 and a Cr / Au lower electrode 21 are formed by a normal sputtering method or the like. Finally,
Cleavage is performed at a cavity length of 1150 μm so that a window structure having a length of 25 μm is disposed on both end surfaces, and a SiON film 23 for low reflection coating is formed on both end surfaces by a normal sputtering method or the like.
The chip size of the entire array is 160μm x 1150μm
That is, an 8-channel array semiconductor optical amplifier with an extremely small spot size converter.

As characteristics, good characteristics are obtained in all channels such that the optical gain is 10 dB ± 0.2 dB with respect to input light having a wavelength of 1560 nm when the injection current to the amplifier is 30 mA, and the coupling loss with the flat end optical fiber is 3.5 dB ± 1 dB. Could be obtained. Using a bulk layer for the active layer, W
Since 0 = 0.6 μm, the cross-sectional shape of the optical waveguide layer to be selectively grown was substantially rectangular, and the gain characteristics of the amplifier could be made polarization independent of the TE wave and the TM wave. In addition, quartz-based Planer Lightwave Circuit (PL
C) and passive alignment were performed, and the gate switch operation was confirmed. As a result, a good switch operation with an extinction ratio of 50 dB or more for all the channels with input light having a wavelength of 1560 nm could be achieved.

Embodiment 4 This embodiment is an embodiment in which the semiconductor optical device having an array structure according to the present invention is applied to a microarray wavelength selective light source.
FIG. 17 is a layout view of a diffraction grating, FIG. 18 is a plan view of a mask,
19 is a perspective view showing the structure of the wavelength selection light source.
The microarray wavelength selection light source 400 of the present embodiment is the same as that of FIG.
As shown in FIG. 9, this is a wavelength-selective light source of an extremely small size monolithically integrated on an InP substrate, and the light source mainly includes five regions. That is, the wavelength selection light source 400 has 1) a DFB laser region, 2) a multiplexer region, and 3) multi-mode interference (Multi Mode Interference).
Area, 4) optical amplifier area, and 5) optical modulator area.
It is composed of one.

[0064] The method for manufacturing a wavelength selective light source 400 Firstly, as shown in FIG. 17, be drawn using an electron beam exposure method a diffraction grating pattern 88 on the n-InP substrate 99 only in the DFB laser region. Specifically, 11.
5 μm interval, 5 μm width × 400 length per array
Draw in 8 μm channel area. At this time, the oscillation wavelength of each channel in the laser region is set to 1 for all 8 channels.
536-1547.2 nm (i.e., 1.
In this case, the period of the diffraction grating of the channel 1 is set to 240 nm, the period of the adjacent channel is increased by 0.25 nm, and the period of the diffraction grating of the channel 8 is set to 241. 7
The thickness is set to 5 nm. This diffraction grating pattern 88
Is transferred onto an n-InP substrate 99 by ordinary wet etching or the like to form a diffraction grating 88 having a depth of 60 nm.

Next, as shown in FIG. 18, an SiO ₂ mask for selective growth is formed on the substrate 99 on which the diffraction grating is formed. At this time, the mask width of each region is set as follows. 1) DFB laser area: 8 array intervals 1
1.5 μm, Wa = 10 μm, Wm1 = 20 μm, Wm2 =
50 .mu.m, growth area width W0 = 1.5 .mu.m, 2) multiplexer area: array distance 11.5 to 2.5 .mu.m, distance 300
Change in μm. Growth area width W0 = 1.5 μm, mask width Wm3 = 1 μm in all areas, 3) MMI area: growth area width W0 = 19 μm, mask width Wm4 = 20 μm, 4)
Optical amplifier area: growth area width W0 = 1.5 μm, mask width Wm5 = 60 μm, 5) optical modulator area: growth area width W0 =
1.5 μm, mask width Wm6 = 40 μm. Further, in order to introduce a window structure on both end surfaces of the device, a SiO ₂ film having a width of 25 μm
The mask 5 is arranged at the end face position.

On the substrate on which these masks are formed, a layer structure similar to that of FIG. 10 of the first embodiment, that is, an n-InGaAsP semiconductor layer 11 having a 1.13 μm composition, an n-InP spacer layer 12, and a 1.20 μm composition N-InGaAsP light confinement layer 13, 1.50 μm composition compressively strained InGaAsP
Well / MQW layer 14 composed of a 1.20 μm InGaAsP barrier, InGaAsP optical confinement layer 15 having a 1.20 μm composition, and p-InP
The layer 16 is selectively grown by metal organic chemical vapor deposition (MOVPE) or the like. The growth conditions were a pressure of 150 Torr and a temperature of 650.
° C. At this time, the peak wavelength of the photoluminescence (PL) of the MQW layer can be changed from 1) DFB laser region: 1535 to 1550 nm in channels 1 to 8; 2) multiplexer region: 1380 n in all channels.
m, 3) MMI area: 1300 nm, 4) optical amplifier area: 1542 nm, 5) optical modulator area: 1472 nm. As a result, 1) In the DFB laser region, the gain peak wavelength of the MQW layer can be changed by following the laser oscillation wavelength of each channel determined by the period of the diffraction grating, and the detuning amount (oscillation wavelength) of each channel (A difference between the gain peak wavelength and the gain peak wavelength) could be maintained at a favorable value of ± 10 nm or less.

After forming each semiconductor layer in this manner, the mask opening width W0 of the SiO ₂ mask is set to 1) DFB
Laser area, 2) optical amplifier area, 3) optical modulator area
One region is formed again so as to have a thickness of 1.5 μm to 5 μm. Further, 4) the SiO ₂ mask in the MMI region is entirely removed, and 5) in the multiplexer region, SiO ₂ is formed again so as to cover the growth region having the width W0. Using this mask,
An embedded structure similar to that of FIG. 10 of the first embodiment, that is, p-In
P buried cladding layer 17 (layer thickness 3 μm), p ⁺ -In
The GaAs contact layer 18 (layer thickness 0.3 μm) is
Grow by PE. As a result, 1) DFB laser area, 2) optical amplifier area, 3) optical modulator area, 4) MMI
In the region, a buried waveguide structure is formed, and in the 5) multiplexer region, a high-mesa waveguide structure is formed. After that, Si
An O ₂ film 19 is formed, a current injection window is formed only in the DFB laser region, and a Cr / Au upper electrode 20 and a Cr / Au
The lower electrode 21 is formed by a usual sputtering method or the like.

Further, an SiO ₂ film is again formed on the entire area. 1) The DFB laser area is partially opened as shown in FIG. 19, 2) the optical amplifier area, and 3) the optical modulator area. Open the window. The Cr / Au upper electrode 20 is formed again. That is, the DFB laser region has a double electrode structure so that the electrodes of each channel do not contact each other. After forming the electrodes in this manner, finally, the length of the resonator is set to 1 so that a window structure having a length of 25 μm is arranged on both end faces.
Cleave at 500μm, S on both sides for low reflection coating
By forming the iON film 23 by a normal sputtering method or the like, it was possible to realize a wavelength-selective light source having an extremely small chip size of 300 μm × 1500 μm.

Each D constituting the different wavelength DFB laser array
Since the detuning of the FB laser is appropriately controlled, the characteristics of each laser are as follows.
1547.2 nm, 25 ° C. in all channels, threshold current 9 mA ± 1 mA at CW, injection current 20 into optical amplifier
In mA, good and uniform characteristics of an optical output of 20 mW ± 1 mW ＠ 150 mA could be obtained. Further, as the modulation characteristics of the optical modulator, it was possible to achieve 2.5 Gbit / s-600 km transmission with respect to the oscillation wavelengths of all the channels. Since the window structure was introduced on both end faces and the coating was low-reflection coated, the yield in which single-mode oscillation was obtained in all channels was as good as 50% or more.

Further, the present invention has a great advantage when applied to an optical module. For example, as shown in FIG. 20, FIG. 20 (a) shows a schematic diagram of the arrangement of optical fibers and laser arrays in an optical module when a four-channel semiconductor laser array is used. For example, in the present invention, the entire array width of the semiconductor laser array is as shown in FIG.
As shown in FIG. 0 (a), it is minimized to about 30 μm,
By using the optical fiber 2 having a relatively large core diameter of μm, all output light from the semiconductor laser array can be directly coupled (directly extracted) to the optical fiber. That is, an optical system such as a condenser lens for outputting light is not particularly required.
On the other hand, FIG. 20B shows a case where the number of arrays increases. When the number of arrays increases to, for example, six, and becomes about the core diameter of the optical fiber (for example, 50 μm), the semiconductor laser is simply inserted between the optical fiber 2 and the semiconductor laser array. All output light from the array can be directly coupled (direct output) to the optical fiber, in which case no integration of the optical multiplexer is required.

FIG. 20C is a schematic structural view of an optical module having such a lens. The optical module includes a semiconductor laser array 31 in which semiconductor lasers are arranged at a minimum array period, an optical fiber 32, and a light receiving element 3 so that the entire array width is equal to or less than the core diameter of the optical fiber.
3, a Peltier element 34, a lens 35, a lens support 36, and the like. By using the extremely small semiconductor laser array 31 according to the present invention and the optical fiber 32 having a core diameter of 50 μm or more, the optical output from each channel of the multi-channel semiconductor laser array 31 can be obtained without using an integrated optical multiplexer. Lens condensing allows direct coupling to a single optical fiber.

The size of the semiconductor laser array element, including the electrode section, is about 250 μm in width and about 300 μm in length, which is the same as the size of a conventional one-chip element. It is possible to achieve a size as small as a normal semiconductor laser optical module. As a result, the production process and yield of the optical module have been greatly improved, and low-cost supply of the semiconductor laser array optical module has become possible. When the entire width of the semiconductor laser array is sufficiently smaller than the core diameter of the optical fiber, the condenser lens 35 is not required. As a result, the number of components of the optical module can be further reduced, and the manufacturing process can be further simplified, so that further reduction in cost can be realized. In the semiconductor laser array shown in FIGS. 20 (a) and 20 (b), the laser of each channel can be independently driven by providing an electrode 7 at a position where a current injection window is partially opened.

The semiconductor optical device having an array structure according to the present invention has a great advantage in mounting the light receiving device 33. That is, as shown in FIG. 20, since the entire width of the semiconductor laser array is very narrow, about 50 μm or less, a single light receiving element can receive light of all channels.
As a result, the number of light receiving elements required for the optical module was conventionally required to be the same as the number of channels, but this can be greatly reduced, and the chip size can be reduced and the manufacturing process can be simplified as described above. And further contributed to further lowering the cost of the optical module. Hereinafter, application examples of the optical module of the present invention will be described with reference to examples and drawings. As described above, when the present invention is applied to an optical module using the ultra-small array semiconductor optical device according to the present invention, it is possible to drastically reduce the size, cost, and yield of the optical module.

Example 5 Multi-wavelength semiconductor Fabry-Perot (FP) laser array
Joule Figure 21 is a fifth embodiment of the present invention, illustrating a configuration of a multi-wavelength semiconductor Fabry-Perot (FP) laser array optical module. This optical module has an eight-channel multi-wavelength FP laser array 41 in which FP lasers having different oscillation wavelengths in each channel are arranged at a minimum array period of 7 μm.
An optical fiber 32 having a core diameter of 60 μm;
3 and a Peltier element 34. Since the entire array width of the 8-channel laser array 41 is 60 μm or less, the light output from the laser array is:
All are coupled by a lens 35 to an optical fiber having a core diameter of 60 μm. As the electrode 37 of the FP laser array, a double electrode structure with a partially opened window was used so that current could be independently injected into each channel.

The active layer of each semiconductor laser constituting the laser array is composed of a multiple quantum well (MQW) layer 39, and a light output of 10 mW or more is confirmed by low threshold current oscillation of about 10 mA in each channel. did. The oscillation wavelength of each channel is ch.1 = 1530 nm, ch.2 = 15
40 nm, ch. 3 = 1550 nm, ch. 4 = 1560 n
m, ch. 5 = 1570 nm, ch. 6 = 1580 nm, c
h.7 = 1590 nm and ch.8 = 1600 nm. The element size of the multi-wavelength FP laser array is 25
The optical module is as small as 0 μm and 390 μm in length, and the optical module can be reduced in size and cost as much as a normal semiconductor laser.

Embodiment 6 Multiwavelength Semiconductor DFB Laser Array Optical Module FIG. 22 shows a multiwavelength semiconductor D according to a fifth embodiment of the present invention.
1 shows a configuration of an FB laser array optical module. This optical module includes an 8-channel different-wavelength DFB laser array 45 arranged at a minimum array period of 10 μm intervals, an optical fiber 32 having a core diameter of 80 μm, a light receiving element 33, a Peltier element 34, a lens 35, a lens support 36, And a wavelength filter 38. Since the entire width of the eight-channel laser array 45 is 70 μm or less, all the optical outputs output from the array are coupled by the lens 35 to an optical fiber having a core diameter of 80 μm. DFB
The element size of the laser array is 250 μm in width and 30 in length.
By using the diffraction grating 10 having a different period for each channel, the oscillation wavelength is 0.8 nm at a time centered at 1550 nm and 0.8 nm in accordance with the ITU grid.
The entire array is changed by about 5.6 nm. The active layer of each DFB laser constituting the array was composed of a multiple quantum well (MQW) layer 39, and light output of 20 mW or more was confirmed by low threshold current oscillation of about 5 mA. The oscillation wavelength of each channel of the laser array is determined by monitoring the intensity of light transmitted through a wavelength filter 38 such as a dielectric multilayer film wavelength filter with a light receiving element and feeding it back to a specified temperature using a Peltier element 34. It can be locked to the oscillation wavelength.
By using the DFB laser array 45, the mode stability of the oscillation wavelength was improved, and an optical module more suitable for communication applications could be obtained.

Embodiment 7 Tunable DBR Laser Array Optical Module A tunable DBR laser array optical module according to a seventh embodiment of the present invention is shown in FIG. Variable D
It has been replaced with a BR laser array. FIG. 23 shows a schematic structural diagram of a DBR laser per channel. The 8-channel DBR laser array sets the center oscillation wavelength of each channel to ch.1 = 1535 nm, ch.2 = 1540 nm, ch.3 = 1545n.
m, ch.4 = 1550 nm, ch.5 = 1555 nm, ch.6 = 1560 nm, ch.7
= 1565 nm and ch.8 = 1570 nm. The bulk active layer 43 was used as the active layer so that a sufficient gain could be generated in a wide wavelength range. The DBR laser includes an active region and a wavelength tuning region including a diffraction grating region and a phase control region. By controlling the tuning current through the wavelength tuning electrode 42, a wavelength tunable operation of 5 nm per channel is possible. Was. As a result, a wavelength tunable DBR laser array optical module capable of performing single mode oscillation over a wide wavelength range of 35 nm as the entire array was realized.

Embodiment 8 DFB Laser Array Optical Module with Spot Size Converter
A eighth embodiment of the present invention to Lumpur Figure 24, the spot size converter: shows the (Supot Size Convertor SSC) DFB laser array optical module with. The DFB laser array optical module with 6-channel SSC is obtained by replacing the 8-channel multi-wavelength semiconductor FP laser array of FIG. 21 with a DFB laser array with 6-channel multi-wavelength SSC and by replacing the core diameter of an optical fiber of 125 μm. I have. FIG. 24 is a structural perspective view of one channel of a DFB laser array with SSC fabricated on an InP substrate.
(A). The device includes a laser region and an SSC region, and the layer thickness and composition of the MQW optical waveguide in the SSC region are gradually thinner and shorter in wavelength from the laser region boundary to the end surface of the SSC region. The width of the InP cladding 44 is 7 μm, and the width of the MQW active layer 39 is 1.5 μm.
Fig. 2 is a schematic cross-sectional view of the laser side for six channels.
This is shown in FIG. The period of the array is 20 μm, the entire width of the array is about 100 μm, and the core diameter of the optical fiber 32 is 1 μm.
It is smaller than 25 μm. The device size was 400 μm for the laser region, 250 μm for the SSC region, and 300 μm in chip lateral width, which were equivalent to the size of a conventional one-chip semiconductor optical device. FIG. 24C is a schematic diagram showing the structure when the optical module is mounted on an optical module. Since an SSC structure is added and the spot size at the light emitting end can be reduced, the optical output of the entire array can be reduced to a core diameter of 12 without using a lens.
It could be directly coupled with a 5 μm optical fiber. The oscillation wavelength of each channel is 1546.8nm and 1548.4n, respectively.
m, 1550 nm, 1551.6 nm, 1553.2 nm, and 1554.8 nm, and the wavelength channel spacing was 1.6 nm (200 GHz). As described above, the DFB laser array optical module with the spot size converter of the present invention uses the SSC structure to reduce the coupling loss with the optical fiber as compared with the case where the SSC structure as in the sixth embodiment is not used. The reduction was about 3 dB.

In the sixth embodiment described above, an example in which a layer thickness taper structure in which a layer thickness is tapered is used for the SSC structure. The present invention can be applied to any other SSC structures other than the above examples, for example, those in which the width of an MQW optical waveguide is changed into a tapered shape, the use of a double optical waveguide, and the like.
Even the one using the C principle can be effectively adopted for an optical module using a semiconductor laser array in which an SSC structure is integrated.

Embodiment 9 High Power 0.98 μm Band Semiconductor Laser Array Optical Module FIG. 25 shows a ninth embodiment of the present invention, a high output 0.98 μm.
1 shows a configuration of a μm band semiconductor laser array optical module.
As shown in FIG. 25A, the semiconductor laser array has five channels, and in order to increase the output in each channel, the optical waveguide has a tapered structure with a rear end of 2 μm and a light emitting end of 10 μm. The channel spacing is 20 μm and the total array width is 80 μm. The resonator length is 900 μm, the chip width is 250 μm, the current injection electrodes are common to all channels, and the entire array is driven at one time. Then, the optical outputs of all the arrays are coupled to one optical fiber (core diameter 100 μm) via a lens. FIG. 25B is a cross-sectional view of the optical module. The maximum optical output of such an optical module is 250 mW per channel, and an optical output exceeding 1 W can be realized by such a module out as the whole array.

In the ninth embodiment of the present invention, an example in which a lens is used for an optical module has been described. However, a high output 0.98 μm, in which the core diameter of the optical fiber is made wider and the lens is not used, is used. The present invention is also effective for a band semiconductor laser array optical module (980 nm, bandwidth ± 10 nm). In the above-described ninth embodiment of the present invention, the example of the high-power semiconductor laser array optical module having the oscillation wavelength of 0.98 μm was shown. However, the present invention is applied to other wavelength bands, for example, 2 to 10 μm band (2000 to 10, 000nm
Band), 1.55 μm band (1,550 nm band), 1.48
μm band (1480 nm band), 1.3 μm band (1,300
nm band), 0.2-1 μm band (200-1,000 nm)
Bands) are also very effective in coupling a large optical output to an optical fiber having a large core diameter. In particular, in the case of a 1.48 μm band high power semiconductor laser array as a light source for exciting an erbium-doped optical fiber, a DFB structure having both high power characteristics and multi-wavelength characteristics is used at 1.48 μm.
The present invention is very effective when configuring a high output multi-wavelength DFB laser array optical module in the μm band.

In the first embodiment of the present invention, the example of the microarray distributed feedback (DFB) type semiconductor laser in which detuning is controlled to an appropriate value (± 10 nm) has been described. However, the DFB laser of the first embodiment is a DBR laser. The present invention is also effective in the case where it is replaced with a DR laser, a gain coupling type laser or the like.

In the second embodiment of the present invention, an example of a microarray different wavelength semiconductor laser with a spot size converter has been described. However, the semiconductor laser of the second embodiment is a DFB laser having a diffraction grating, a DBR laser, a DR laser, The present invention is effective even when replaced with a gain-coupled laser or the like.

Since the microarray semiconductor optical amplifier with the spot size converter shown in the third embodiment of the present invention can be coupled to an optical fiber or the like with low loss, an external resonator type optical amplifier combined with a fiber grating can be used. This is very effective also in the case of forming a one-mode laser because the entire element size can be reduced. Furthermore,
Quartz-based planar lightwave circuit (PL
C) can also be coupled with low loss, so that it is very effective also when configuring a functional device hybrid-mounted with a quartz PLC. For example, Reference: 1997
Quartz-based planar lightwave circuit (PLC) on which diffraction gratings with different periods are formed as shown in IEICE Electronics Society Conference, Proc. By hybrid mounting the microarray semiconductor optical amplifier shown in Example 3, it is possible to configure an external resonator type different wavelength single mode laser whose longitudinal mode is controlled with a small size of 1/10 or less of the conventional one. .

The present invention is also very effective for manufacturing a semiconductor laser array that oscillates in one transverse mode as a whole, that is, a super mode due to mutual interference of propagating lights between the optical waveguides constituting the array.

The present invention also relates to materials other than InGaAsP / InP, such as InGaAsN / GaAs,
It is also effective in an optical integrated device using a material such as GaAlAs / InGaAsP and a selective growth for realizing the same. In the present invention, the opening width of the SiO ₂ mask is set to 1.5 μm.
Although an example in which an optical waveguide is formed by selective growth with m as described above has been described, the present invention is also effective for a selective growth method in which the opening width of a selective growth SiO ₂ mask is further increased.

In the sixth to eighth embodiments of the present invention, DFB lasers and DBR lasers have been described as examples of the longitudinal single mode laser array having a diffraction grating. This is also effective for a mode laser array. Such arrays include, for example, distributed reflection (D
R) laser array, gain-coupled DFB laser array,
Complex coupled DFB laser array, superstructure grating (SSG) DBR laser array, tunable twin guide (TTG) type DFB laser array,
DFB using air (dielectric) and semiconductor diffraction grating,
A DBR laser array or the like.

In the eighth embodiment of the present invention, an example of an array optical module in which a semiconductor laser is integrated with an SSC has been described. It is very effective also in the case of an array integrated optical device.

In the case where the operating temperature of a single semiconductor laser is controlled by a Peltier device to perform a wavelength tunable operation, the wavelength range that can be changed while suppressing the characteristic deterioration of the laser oscillation threshold current and optical output is as follows. It is at most about 4 nm (in the case of a change temperature range of about 40 ° C.). That is,
When a semiconductor laser is arrayed to form a multiwavelength semiconductor laser array optical module, the present invention can be used particularly effectively when the wavelength range that can be covered by the entire array is 4 nm or more. In the sixth embodiment of the present invention, an example is shown in which the wavelength range that can be covered by the entire 8ch array is 5.6 nm.
The present invention is also effective for a multi-wavelength DFB laser array in which the number of channels is reduced and the wavelength range that can be covered as a whole is about 4 nm or less. Thus, the present invention is very effective for a multi-wavelength semiconductor laser array optical module that can cover a wavelength range of 4 nm or more. If the number of channels is further reduced, the wavelength range of less than 4 nm can be appropriately covered.

In the present invention, the number of arrays is not particularly limited. For example, considering the minimum number of arrays, the minimum number of arrays can be two. In the case of a semiconductor laser array optical module having two arrays, the minimum core diameter of an optical fiber that can be used is 15 μm when the minimum array interval is about 7 μm.
m. As a result, the present invention can set the diameter of the optical fiber to 15 μm or more, and can be effectively implemented in this case.

On the other hand, as for the maximum number of arrays, the maximum number of arrays can be set to about the array interval × (the number of arrays−1). For example, the maximum number of arrays can be increased until the maximum core diameter of the optical fiber is reached. . In particular, the present invention is very effective when the number of arrays is 16 or less, depending on the electrode arrangement of the elements and the like.

In Examples 5 to 9 of the present invention,
Although an example in which the optical fiber has no diffraction grating is shown, the present invention
For example, an optical fiber coupled with the multi-wavelength semiconductor FP laser array of the sixth embodiment, a diffraction grating such as a fiber Bragg grating is added, and the present invention can be applied to an optical module in which the single mode stability of the oscillation wavelength is improved. The present invention is very effective for such an optical module.

[0093]

According to the present invention, by specifying the width of the dielectric thin film, the array size can be reduced, and the composition and layer thickness can be varied between adjacent optical waveguides constituting the array. And a semiconductor optical waveguide array having uniform optical element characteristics. As a result, the method for manufacturing a semiconductor optical waveguide array and the semiconductor optical device having an array structure according to the present invention can be ultra-highly integrated to an array size of 1/10 or less of the conventional semiconductor optical device. Can be improved by 10 times or more, which is very useful in supplying an array-structured semiconductor optical device at low cost. Furthermore, in the prior art,
Although it was technically difficult to arbitrarily control the bandgap energy of each optical waveguide layer constituting an array in an array-structured semiconductor optical device ultra-highly integrated at an array interval of 50 μm or less, the present invention , It is possible to arbitrarily control the bandgap energy of each optical waveguide layer constituting the array, such as uniform change and linear change, and to uniformize the characteristics of array-structured semiconductor optical devices having ultra-highly integrated diffraction gratings. There is an advantage that the performance can be improved.

[Brief description of the drawings]

FIG. 1 is a view showing a SiO ₂ growth inhibition mask pattern used in selective growth of the present invention.

FIG. 2 is a cross-sectional view showing a laminated structure of each channel.

FIG. 3 is a graph showing the dependency of the photoluminescence (PL) peak wavelength of the MQW layer of Experimental Example 1 on the SiO ₂ mask width Wm.

FIG. 4 is a graph showing the dependence of the optical waveguide layer thickness on the mask width Wm in Experimental Example 1.

FIG. 5 is a graph showing the PL peak wavelength dependence of each channel in Experimental Example 2.

FIG. 6 is a graph showing a PL spectrum of Experimental Example 2.

FIG. 7 is a graph showing the PL peak wavelength dependence of the MQW layer of each channel in Experimental Example 3.

FIG. 8 is a layout diagram of the diffraction grating of the first embodiment.

FIG. 9 is a plan view of a mask according to the first embodiment.

FIG. 10 is a cross-sectional view illustrating a layer structure of the semiconductor laser according to the first embodiment.

FIG. 11 is a plan view of a mask according to a second embodiment.

FIG. 12 is a plan view of a mask according to a second embodiment.

FIG. 13 is a partial cross-sectional perspective view showing a structure of a semiconductor laser according to a second embodiment.

FIG. 14 is a plan view of a mask according to a third embodiment.

FIG. 15 is a plan view of a mask according to a third embodiment.

FIG. 16 is a partial sectional perspective view showing the structure of a semiconductor laser according to a third embodiment.

FIG. 17 is a layout diagram of the diffraction grating of the fourth embodiment.

FIG. 18 is a plan view of a mask according to a fourth embodiment.

FIG. 19 is a perspective view illustrating a structure of a wavelength selection light source according to a fourth embodiment.

FIG. 20 is a schematic diagram of an arrangement of optical fibers and a laser array in an optical module when a four-channel semiconductor laser array is used.

FIG. 21 is a diagram illustrating a structure of a multi-wavelength semiconductor FP laser array optical module according to a fifth embodiment.

FIG. 22 is a diagram illustrating a structure of a multi-wavelength semiconductor DFB laser array optical module according to a sixth embodiment.

FIG. 23 is a diagram showing a structure per channel of a multi-wavelength semiconductor DBR laser array optical module according to a seventh embodiment.

FIG. 24 is a diagram illustrating the structure of a DFB laser array optical module with a spot size converter according to an eighth embodiment.

FIG. 25 is a diagram showing the structure of a high-power 0.98 μm band semiconductor laser array optical module according to a ninth embodiment.

[Explanation of symbols]

Reference Signs List 1 Growth region 2, 3, 4, 5 SiO ₂ mask 11 InGaAsP layer 12 InP layer 13 InGaAsP layer 14 MQW active layer 15 InGaAsP layer 16 InP layer 17 p-InP cladding layer 18 p ⁺ -InGaAs contact layer 19 SiO ₂ 20 p Electrode 21 n electrode 22 high reflection coating film 23 low reflection coating film 24 InP buffer layer 25 InGaAsP bulk layer 31 semiconductor laser array 32 optical fiber 33 light receiving element 34 Peltier element 35 lens 36 lens support 37 electrode 38 wavelength filter 39 MQW active layer Reference Signs List 40 diffraction grating 41 FP laser array 42 tuning electrode 43 bulk active layer 44 InP clad 45 DFB laser array 46 DFB laser array with SSC 47 0.98 μm band semiconductor laser array 77 dummy growth region 99 of the semiconductor laser 200 Example 2 of the InP substrate 100 Example 1 a semiconductor laser 300 the optical amplifier 400 wavelength selective light source

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-9-36473 (JP, A) IEICE Technical Report OPE94-110, 1994, Vol. 94 No. 493, p. 13-18 Journal of Crystal Growth, 2000, 221, p. 189-195 Superlattices and Microstructures, 1996, 20 [1], p. 111-116 IEICE Technical Report OCS 99-69, 1999, Vol. 99 No. 372, p. 31-34 (58) Field surveyed (Int. Cl. ⁷ , DB name) H01S 5/00-5/50 G02B 6/122

Claims (28)

(57) [Claims] 1. A semiconductor multi-layer structure having a quantum well layer or a semiconductor multi-layer structure including a bulk layer is selectively crystal-grown in a stripe-shaped growth region formed between dielectric thin films on a substrate. In a method of manufacturing a semiconductor optical waveguide array having a plurality of optical waveguides in an array, a plurality of stripe-shaped growth regions extending in parallel are formed sandwiching a dielectric thin film, respectively, and a quantum is selectively formed in each growth region. When a semiconductor multilayer structure having a well layer, or a semiconductor multilayer structure including a bulk layer is subjected to crystal growth by metal organic chemical vapor deposition, each of the growth regions has a length greater than a diffusion length of a source species in a reaction tube during crystal growth. The widths of the dielectric thin films disposed between the respective growth regions are parallel to each other at short intervals, and the width of the dielectric thin film is Wa, and the first thin film is disposed outside the two outermost growth regions. Invitation The width of the body thin Wm1 and second outermost dielectric width Wm2 of the thin film, Wm1> Wa and Wm2> method of manufacturing a semiconductor optical waveguide array, which is a Wa. 2. The composition or layer of each semiconductor optical waveguide forming an array by setting the width Wm1 of the first outermost dielectric thin film and the width Wm2 of the second outermost dielectric thin film to Wm1 ≠ Wm2. 2. The method for manufacturing a semiconductor optical waveguide array according to claim 1, wherein the thickness is changed. 3. The method of manufacturing a semiconductor optical waveguide array according to claim 1, wherein each region sandwiched between the plurality of growth regions is completely covered with a dielectric thin film. 4. The method according to claim 1, wherein an interval between adjacent ones of the plurality of growth regions is 50 μm or less.
4. The method for manufacturing a semiconductor optical waveguide array according to any one of items 1 to 3. 5. The width of each of the plurality of growth regions is 1
The method of manufacturing a semiconductor optical waveguide array according to claim 1, wherein the thickness is 0 μm or less. 6. The array is formed by changing the number of the plurality of growth regions or at least one of the widths Wa, Wm1 and Wm2 of the dielectric thin film along the longitudinal direction of the growth region. 6. The semiconductor optical waveguide array according to claim 1, wherein a composition or a layer thickness of each of the constituent optical waveguides is changed along a longitudinal direction of the growth region. Production method. 7. The semiconductor optical waveguide according to claim 1, wherein an interval between the semiconductor optical waveguides is changed by changing an interval between the plurality of growth regions along a longitudinal direction of the growth region. The method for manufacturing a semiconductor optical waveguide array according to any one of the above items. 8. A semiconductor optical waveguide array wherein at least one of the width of each of the plurality of growth regions, the interval between the growth regions, and the width Wa, Wm1, and Wm2 of the dielectric thin film is formed on a substrate. The method for manufacturing a semiconductor optical waveguide array according to any one of claims 1 to 7, wherein the method differs from one another. 9. The method according to claim 1 , wherein
An array-structured semiconductor optical device manufactured by the method. 10. A semiconductor multilayer structure having a quantum well layer or a semiconductor multilayer structure including a bulk layer is formed in a stripe-shaped growth region formed between a dielectric thin film on a substrate.
In a semiconductor optical device provided with an optical waveguide formed by selective crystal growth by MOVPE vapor phase growth , the optical waveguides are arranged in an array at intervals shorter than the diffusion length of the raw material species in the reaction tube during crystal growth. Are arranged in the form of an array
Optical waveguides are grown collectively by the selective crystal growth
Array structure semiconductor optical device according to claim Monodea Rukoto. 11. The optical waveguide according to claim 11, wherein the number of optical waveguides arranged in an array is 16 or less.
11. The semiconductor optical device having an array structure according to item 10 . 12. The semiconductor optical device having an array structure according to claim 10 , wherein a plurality of said optical waveguides are arranged in an array at an interval of 50 μm or less. 13. The optical waveguide, wherein the width of the optical waveguide is 10 μm or less, and the side wall of the optical waveguide is formed by selective growth.
Claims 9, characterized in that 1) a B crystal plane 12
3. The semiconductor optical device having an array structure according to item 1. 14. The band gap energy of selectively grown crystals, or at least one is selected from the layer thickness, any of claims 9, characterized in that different between adjacent optical waveguides 1 3 1 Item 14. An array-structured semiconductor optical device according to item 5. 15. The array optical waveguide is composed of the semiconductor bulk active layer, by current injection to any one of claims 9 to 1 4, characterized in that it has the function of an optical amplifier causes an optical gain An array-structured semiconductor optical device according to claim 1. 16. The arrayed optical waveguide comprises a multiple quantum well layer (MQW), has a light reflecting mechanism at both ends of the optical waveguide or near the optical waveguide, and generates an optical gain by current injection. , array structure semiconductor optical device according to any one of claims 9 to 1 5, characterized in that a laser oscillation of. 17. The array structure semiconductor optical device according to claims 9 to 1 4, or 1 6 any one of the reflection function of the light is equal to or caused by the diffraction grating provided in the vicinity of the optical waveguide . 18. The array structure semiconductor optical device according to claim 1 7, wherein the different between optical waveguide period of the diffraction grating is adjacent. 19. The array structure semiconductor according to any one of claims 9 to 1 8, characterized in that at least one of the light spot size converter to an end of said arrayed optical waveguides are integrated Optical element. 20. At least one end of the arrayed optical waveguide is provided with a star coupler, a multi-mode interferometer (MMI,
The array-structured semiconductor optical device according to any one of claims 9 to 19 , wherein at least one optical multiplexer selected from Multi Mode Interference is integrated. 21. The semiconductor optical device according to claim 9, wherein the array-structured semiconductor optical device is a semiconductor laser array having an oscillation wavelength in the range of 970 to 990 nm.
19. The semiconductor optical device having an array structure according to any one of items 1 to 18. 22. The semiconductor optical device according to claim 9, wherein said array-structured semiconductor optical device is a semiconductor laser array having an oscillation wavelength in the range of 1450 to 1510 nm.
19. An array-structured semiconductor optical device according to any one of items 6 to 18. 23. A quartz-based plan having a semiconductor optical device having an array structure according to claim 14 and a diffraction grating formed thereon.
ER Lightwave Circuit (PLC) and a hybrid resonator type multi-wavelength light source characterized by being hybrid-integrated. 24. Any one of claims 9 to 23
An optical module, characterized in that at least one of the array-structured semiconductor optical elements described in the above section is used. 25. The optical module according to claim 24, further comprising an optical element for substantially condensing light output from the semiconductor optical elements arranged in an array, and extracting the light output. 26. Light comprising at least an array-structured semiconductor optical device, an optical fiber for deriving an optical output from the array-structured semiconductor optical device, and a light-receiving device for monitoring the optical output from the array-structured semiconductor optical device. A module, wherein the array-structured semiconductor optical device is a module.
2. An at least one array-structured semiconductor optical device selected from the arrayed-structured semiconductor optical device according to claim 1, wherein substantially all light emitted from the arrayed-structure semiconductor optical device is led out by the optical fiber. An optical module, comprising: 27. The optical module according to claim 24 , further comprising a wavelength filter for controlling a wavelength output from the semiconductor optical elements arranged in an array. . 28. An optical communication system using at least one of the array-structured semiconductor optical devices according to claim 9 .