JP2000332350A - Grating waveguide path integrated active device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-size grating waveguide path integrated active device which can transmit a high speed signal without a kink. SOLUTION: A laser oscillation section 20 and a waveguide path grating section 21 are integrally formed on one substrate so that the length L of a resonator of the laser oscillation section 20 can be reduced, the modulation bandwidth can be higher, and higher speed signals can be transmitted. Since a three-dimensional waveguide path containing GeO2 having a high refractive index is formed on the side of a laminate 19 where laser beam is emitted, there is little reflection at an interface of the three-dimensional waveguide path, a side-mode suppression ratio can be made large and a laser oscillating device without a kink can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a grating waveguide integrated active device.

[0002]

2. Description of the Related Art Research and development of an optical active device that satisfies both high functionality, high performance, small size, and low cost of an optical device has been attracting attention.

FIG. 7 is an external perspective view showing a conventional example of an optical active device.

This optical active device is a semiconductor laser with a slab waveguide having a half mirror 47. Light emitted from a ridge-type stripe laser 41 formed on a GaAs substrate 40 is a slab-shaped core 44-1.
Is incident into the convex-shaped collimator waveguide 42 having the following formula, propagates while being diverged in the horizontal direction of the core 44-1, and is collimated by the convex-shaped collimator waveguide 42 on the end face in the middle. The collimated parallel light propagates in the core 44-2 of the half mirror waveguide 43, and
Divided by seven. The half mirror 47 is a groove formed obliquely to the optical axis, 45-1 and 45-2 are lower claddings, and 46-1 and 46-2 are upper claddings. 70 is a lower cladding, 71 is an active layer, 7
2 is an upper clad, 73 is a contact layer, 74 is a reflective film, and 75 is an electrode.

In this configuration, since a slab-shaped waveguide (a waveguide using a polyimide material) is formed on the same GaAs substrate 40 as the ridge-type stripe laser 41, the size, cost, and cost are reduced. Functionalization can be expected together (Higurashi, et al., Semiconductor Laser with Polyimide Waveguide, IEICE Technical Report OPE98-6, p.85-p.89, '
98-8).

Next, a description will be given of a conventional example of a laser with a passive optical component for the purpose of obtaining high performance characteristics.

FIG. 8 is a schematic structural view showing a conventional example of a laser with a fiber grating.

This laser with a fiber grating is intended for a laser having excellent wavelength controllability and stability, and has a configuration in which a fiber grating 53 is provided outside the semiconductor optical amplifier 50. As a result,
The laser resonator is formed by a high reflection film (reflectance: about 80%) 51 formed on the rear end face of the semiconductor optical amplifier 50 and the equivalent reflection surface 57 of the fiber grating 53, and the length of the resonator is represented by L ( Kato et al., Fiber grating external cavity type multi-wavelength laser array, IEICE Technical Report OPE97-
1, p. 1 to p. 6, '97 -5).

In this configuration, since the temperature dependence of the refractive index of the core 54 and the cladding 55 of the fiber grating 53 is smaller than the temperature dependence of the refractive index of the semiconductor, the temperature dependence of the oscillation wavelength is small. . In addition,
In the figure, the front end face of the semiconductor optical amplifier is coated with a low-reflection film (reflectance <0.3%) 52, and the front end of the fiber grating 53 is processed so as to have a rounded portion 56. The optical coupling efficiency between the fiber grating 53 and the fiber grating 53 is increased, and high-output light 58 is extracted from the other end of the fiber grating 53.

[0010]

However, the prior art shown in FIGS. 7 and 8 has the following problems.

(1) Although the configuration shown in FIG. 7 can be expected to be smaller, lower in cost and higher in function as described above, it has a problem in performance. First, since the waveguides 42 and 43 are slab waveguides, light emitted from the ridge-type stripe laser 41 diverges in the horizontal direction and propagates in the waveguides 42 and 43. Therefore, a coupling lens is required to output the light to the optical fiber. Further, it is difficult to couple light propagating through the slab waveguide to the optical fiber efficiently. In addition, since the convex-shaped collimator waveguide 42 made of polyimide is formed on the emission end face of the ridge-type stripe laser 41, the reflectance of the emission end face of the ridge-type stripe laser 41 decreases, and the oscillation efficiency decreases. .

(2) The configuration shown in FIG. 8 can be expected to be a laser excellent in wavelength controllability and stability, but it is a hybrid configuration of individual optical components, so it is difficult to reduce the size and cost of mounting. is there. Further, the Fabry-Perot mode of the semiconductor optical amplifier, which is generated between the high reflection film 51 and the high reflection film 51 due to the residual reflection of the low reflection film 52 on the front end surface of the semiconductor optical amplifier, is superposed, and the side mode suppression ratio decreases. Would.
The kink phenomenon that the light output changes discontinuously with respect to the current due to the residual reflection of the low reflection film 52 occurs.
Furthermore, the resonator length L becomes longer due to the hybrid coupling, and there is a limit in increasing the modulation band, and it becomes difficult to transmit a higher-speed signal.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide an active device integrated with a grating waveguide which can transmit a high-speed signal in a small size and does not generate a kink.

[0014]

In order to achieve the above object, a grating waveguide integrated active device according to the present invention comprises a laser lamination having at least an active layer sandwiched between upper and lower clad layers on an upper surface of a substrate. And a waveguide having a high-refractive-index insulating layer having a substantially rectangular cross-sectional shape in which a low-refractive-index insulating layer is formed at least on the outer periphery, is provided adjacently, and the active layer and the high-refractive-index layer are optically coupled. A light reflection film is formed on the end face of the laser oscillation laminate opposite to the waveguide, a grating is formed on the high refractive index insulating layer of the waveguide, and a forward current is applied to the laser oscillation laminate. When injected, laser oscillation light having a desired wavelength determined by the equivalent reflection surface of the light reflection film and the grating is emitted from the end face of the waveguide opposite to the laser oscillation laminate.

In addition to the above structure, in the grating waveguide integrated type active device of the present invention, it is preferable that each layer of the substrate and the lasing lamination is made of a compound semiconductor.

In addition to the above configuration, the active device with a grating waveguide of the present invention has a high refractive index
It preferably contains eO ₂ .

In addition to the above configuration, in the grating waveguide integrated type active device of the present invention, the active layer may have a slab shape or a substantially rectangular cross-sectional shape.

In the active device integrated with a grating waveguide according to the present invention, a lower clad layer having a slab shape and an active layer having a slab shape or a substantially rectangular cross section are sequentially formed on an upper surface of a compound semiconductor substrate having an electrode on a lower surface. An upper cladding layer is formed so as to cover the contact layer, a contact layer and an upper electrode are sequentially formed on the upper cladding layer to form a laminate, and a high reflection film is formed on one end surface of the laminate.
All the layers on the other end face side of the stacked body and part of the upper surface side of the compound semiconductor substrate are removed to form a stepladder-shaped stacked body, and the upper surface of the compound semiconductor substrate is partially removed. a slab of low refractive index dielectric layer is formed, so that one end surface of the high refractive index insulating layer of substantially rectangular cross-section containing GeO ₂ of high refractive index on the low refractive index dielectric layer is bonded to the active layer A low-refractive-index insulating layer is formed so as to cover the high-refractive-index layer to form a waveguide, and a grating is formed on the high-refractive-index insulating layer between the upper electrode and the lower electrode of the active device. When a forward current is injected into the waveguide, laser oscillation light determined by the equivalent reflection surface of the high reflection film and the grating is emitted from the other end face of the waveguide.

In addition to the above structure, the active device integrated with a grating waveguide according to the present invention is characterized in that the low refractive index insulating layer and the high refractive index insulating layer of the waveguide include SiON, S containing nitrogen.
Any of iONH and Si ₃ N ₄ may be used.

In addition to the above structure, in the grating waveguide integrated type active device of the present invention, it is preferable that one end face and the other end face of the laminate are formed obliquely at an angle of 10 ° or less.

In addition to the above configuration, in the grating waveguide integrated type active device of the present invention, it is preferable that the end face of the waveguide on the side where the laser oscillation light is emitted is formed obliquely at an angle of 10 ° or less.

In addition to the above structure, the active layer of the grating waveguide integrated type active device of the present invention is preferably formed so that the width or thickness is tapered or narrow near the end face on the waveguide side. .

In addition to the above structure, the active device integrated with a grating waveguide according to the present invention has an insulating layer containing high refractive index GeO ₂ having a substantially rectangular cross section at the end face of the waveguide on the side where the laser oscillation light is emitted. Is preferably formed such that the width of the taper becomes narrower or the refractive index gradually decreases.

In addition to the above configuration, in the grating waveguide integrated type active device of the present invention, an optical fiber may be coupled to the end face of the waveguide on the side where the laser oscillation light is emitted.

In addition to the above structure, the active device integrated with a grating waveguide according to the present invention is configured such that the active device integrated with a grating waveguide is configured in an array, and the resonator length of each laminated body is different, and the light is emitted from each waveguide. Preferably, the wavelengths of the laser oscillation light are different.

According to the present invention: (1) Since the resonator can be shortened, the modulation band can be increased and a higher-speed signal can be transmitted.

(2) Since the three-dimensional waveguide containing GeO ₂ having a high refractive index is integrally formed on the other end face side of the laminated body from which the oscillation light is output, the interface of the three-dimensional waveguide is formed. , A large side mode suppression ratio can be obtained, and a laser oscillation device free of a kink phenomenon can be obtained.

(3) Since a high-refractive-index insulating layer containing GeO ₂ and N is used for the core portion of the three-dimensional waveguide having a substantially rectangular cross-sectional shape, a grating can be easily formed by irradiation with ultraviolet light. Can be. In addition, the high-refractive-index insulating layer can be set to a refractive index between the refractive index of the laminate and the refractive index of the optical fiber, and can function as a so-called refractive index matching layer. High optical coupling characteristics can be obtained.

(4) Since one end face and the other end face of the laminated body and the other end face of the waveguide are formed obliquely at an angle of 10 ° or less, instability of laser oscillation due to unnecessary reflected light is induced. Nothing.

(5) Since the three-dimensional waveguide is formed of an insulating layer containing N, the change in the refractive index with respect to a temperature change is extremely smaller than that of a semiconductor or polymer material. Therefore,
The wavelength fluctuation of the laser oscillation light is small with respect to the temperature change.

(6) By providing the mode converter near the other end face of the active layer and the end face of the waveguide on the active layer side, a higher output laser oscillation light can be coupled into the optical fiber.

(7) A high-output multi-wavelength laser oscillator having excellent wavelength controllability and stability can be realized in a small size.

[0033]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 (a) is a front view of the back end face side of a laminate showing an embodiment of a grating waveguide integrated type active device of the present invention, and FIG. 1 (b) is A in FIG. 1 (a).
FIG. 1C is a front view of the front end face side of the laminate, and FIG. 1D is a cross-sectional view taken along the line BB of FIG. 1B.

This active device comprises a laser oscillation section 20 and a waveguide grating section 21. The other end face of the waveguide grating section 21 (the right end face in the figure, hereinafter referred to as "front end face"). Laser oscillation light oscillated at a desired wavelength from 11-3 is emitted in the direction of arrow 22.

This active device has, for example, a laser oscillator whose oscillation wavelength is in the 1.5 μm band. An n-type InP lower cladding layer 2 having a slab structure, an active layer (InGaAsP) 3 and a p-type InP upper first cladding layer 4 are sequentially formed on an n ⁺ -type InP substrate 1, and a p-type InP upper first cladding layer 4 is formed.
A p-type InP upper second cladding layer 5 and an InGaAsP contact layer 6 having a substantially rectangular cross-sectional shape are sequentially formed on the cladding layer 4, and the exposed surface of the p-type InP upper first cladding layer 4 and the p-type InP upper second Cladding layer 5 and InGaAs
The side surface of the P contact layer 6 is covered with a SiON (or SiONH or Si ₃ N ₄ based) film 7 described later.

On the lower surface of the substrate 1, a lower electrode 10 is provided. An upper electrode 8 is provided on the InGaAsP contact layer 6, and when a forward current _Ik is injected from a terminal 9 toward the lower electrode 10, laser light is generated. In order to generate a laser beam, one end face of the stacked body 19 (the left end face in the figure, hereinafter referred to as “rear end face”).
11-1 is provided with a high reflection film (reflectance 75 to 93%) 12.

An end face 11-between the active layer 3 and the core layer 15
The waveguide grating portion 2 is provided on the front side (right side in the figure) of
1 is provided, and a resonator is formed between the equivalent reflection surface 17 and the high reflection film 12 so as to generate laser oscillation. Although the cavity length is represented by L, in the configuration of the present invention, the laser oscillation section 20 and the waveguide grating section 21 are integrally connected, and a conventional air gap layer is interposed between them. The resonator length L can be shortened. As a result, the modulation band can be further increased, and a higher-speed signal can be transmitted.

Next, the waveguide grating section 21 will be described.

The waveguide grating section 21 is made of n ⁺ -type In
When forming on the P substrate 1, first, the end face 11
The −2 side is removed by etching to form a step-shaped laminate. The surface of the substrate 1 is also etched as necessary,
A step 13 is formed. A low refractive index cladding layer (SiON or SiOHH, or Si ₃
N ₄ -based materials, and these materials may further contain a refractive index controlling dopant such as F or B. ) 14-1 is formed. The cladding layer 14-1 is the same as the SiON film 7 of the laminate 19, and can be formed simultaneously.

After the formation of the cladding layer 14-1, the core layer 15 having a substantially rectangular cross section and a high refractive index is formed on the cladding layer 14-1. The core layer 15 may be made of SiON, SiONH, or Si ₃ N ₄ containing GeO ₂ . In addition, these materials contain a refractive index controlling dopant such as P or B, and furthermore, the cladding layer 14-1.
May be added to the core layer 15 so as to cancel the temperature dependence of the refractive index. If such a dopant is added, the filter characteristics of the waveguide grating 21 can be made independent of temperature with respect to a temperature change.

After forming the core layer 15, the core layer 15 is covered again with the clad layer 14-2 of the same material as that used for the low refractive index clad layer 14-1. Cladding layer 14-2
Is irradiated with Kr-F excimer laser light having a wavelength of 240 to 250 nm (or CO ₂ laser light having a wavelength of 10.6 μm) through a phase shift mask (not shown) from above. In this way, the waveguide grating section 21 is formed integrally with the laser oscillation section 20 on the n ⁺ -type InP substrate 1.

In order to increase the optical coupling efficiency between the laser oscillation section 20 and the waveguide grating section 21, the upper second cladding layer 5, the contact layer 6, and the upper electrode 8 having a substantially rectangular cross-sectional structure are connected to each other as shown in FIG. As shown in ()), the width is tapered and narrow near the end face 11-2. By doing so, the spot size conversion of the laser light is performed, and the laser light is efficiently propagated into the core layer 15 of the waveguide grating portion 21.

Although the width is tapered in the embodiment shown in FIG. 1, the thickness may be tapered.

FIG. 2 is a characteristic diagram showing the refractive index characteristics of the materials of the cladding layer and the core layer used in the waveguide grating portion of the active device integrated with a grating waveguide of the present invention. The horizontal axis indicates N in SiOxNyHz. The concentration is shown, and the vertical axis shows the refractive index.

FIG. 2 shows the relationship between the N concentration in SiONH and the refractive index (curve A), and that 10 m of GeO ₂ was added to SiONH.
3 shows a relationship (curve B) between the N concentration and the refractive index when ol% is added. Cladding layers 14-1, 14-
2 is a curve A to which GeO ₂ is not added, and a core layer 15 is a curve B to which GeO ₂ is added.
The amount of GeO ₂ added was 15 mol%, 20 mol%
And the refractive index can be increased substantially linearly with respect to the added amount. GeO ₂ to core layer 15
Is preferably selected from the range of several mol% to 20 several mol%. The addition amount can be selected in consideration of the filter characteristics of the waveguide grating portion 21, the coupling efficiency characteristics with the laser oscillation portion 20, and the like. Note that Si
A dopant for controlling the refractive index and temperature characteristics such as F, B, and P may be added to ONH.

FIG. 3 is a cross-sectional view showing a grating waveguide integrated type active device of the present invention in which an optical fiber is connected to a light emitting end.

The optical fiber 23 is a single mode fiber comprising a normal core layer 24 and a clad layer 25.
In addition to the single mode fiber, a dispersion shift fiber, a wavelength multiplex transmission fiber, or the like can be used. The laser light oscillated at the desired wavelength propagates through the optical fiber 23 and is output in the direction of arrow 26.

FIG. 4A is a front view of a laminated body showing another embodiment of the active device integrated with a grating waveguide according to the present invention, and FIG. 4B is a front view of C in FIG. 4A. FIG. 4C is a front view of the front end face side of the laminate.

This active device is composed of the end faces 11-of the laser oscillation section 20 and the waveguide grating section 21.
The reflected light from the laser oscillators 1, 11-2 and 11-3 is
The end faces 11-1, 11-2, and 11-3 are formed obliquely at angles θ ₁ , θ ₂ , and θ ₃ in order to prevent propagation into the inside of the waveguide 0 and the waveguide grating section 21. is there. The angles θ ₁ , θ ₂ , and θ ₃ are preferably values within 10 °. As the angles θ ₁ , θ ₂ , and θ ₃ are larger, the adverse effect due to the reflected light is smaller, but the optical coupling efficiency is reduced, and the angle θ
_{When 1} , θ ₂ and θ ₃ are small, the characteristics are reversed.

The active device shown in FIG.
The active layer 3 has a substantially rectangular cross section. This active layer 3
It is preferable that the thickness and width are substantially equal, and by making them equal, a filter characteristic having a small difference in optical characteristics (for example, center wavelength characteristic of the filter) due to the polarization plane in the waveguide grating portion 21 can be obtained. can get.
The active layer 3 near the end face 11-2 of the laser oscillation section 20
By providing a spot size converter by making the thickness or width of the taper thinner or narrower as shown in FIG. 1, laser light can be propagated into the waveguide grating portion 21 with higher optical coupling efficiency. Can be.

FIG. 5 is a cross sectional view showing an optical device connected to the grating waveguide integrated type active device of the present invention.

In this active device, the thickness or width of the core layer 15 in the vicinity of the front end face 11-3 of the waveguide grating portion 21 or both of them are formed in a tapered shape as shown in a region 27, so that the optical fiber 23 is formed. And mode field matching.

That is, since the refractive indices of the core layer 15 and the cladding layers 14-1 and 14-2 of the waveguide grating portion 21 are higher than the refractive indices of the core layer 24 and the cladding layer 25 of the optical fiber 23, mode field matching is performed. Need to be taken. By taking this mode-filled matching, the laser light propagating in the waveguide grating portion 21 can be optically coupled into the optical fiber 23 with high efficiency.

FIG. 6A is a side view of the rear end face side of the laser oscillation unit array of the grating waveguide integrated type active device of the present invention (provided that the high reflection film 12 is removed), and FIG. FIG. 6B is a top view of FIG.

This means that four different wavelengths λ ₁ , λ ₂ , λ ₃ , λ ₄ are indicated by arrows 26-1, 26-2, 2
This is an active device array that can output in the 6-3 and 26-4 directions. In this active device array, a laser oscillation unit array 29 and a waveguide grating array 30 are integrally formed on an n ⁺ -type InP substrate 1, and an optical fiber is connected to the other end of each waveguide of the waveguide grating array 30. The optical fiber array 31 composed of 23-1 to 23-4 is connected.

The laser oscillation unit array 29 has a slab-like n
Active layers 3-1, 3-2, 3-3, and 3-4 each having a substantially rectangular cross section are formed in an array on the type InP lower cladding layer 2, and the active layers 3-1 to 3-4 are formed in an array. The upper layer is covered with a p-type InP upper cladding layer 5, and a contact layer 6 is formed on the upper cladding layer 5. Upper electrodes 8-1, 8-2, 8-3, 8-4 separated by separation grooves 28-1, 28-2, 28-3 are formed on the contact layer 6, respectively, and are sequentially and independently formed. Direction currents I _k1 , I _k2 ,
I _k3 and I _k4 are supplied from respective terminals. Each laser oscillation section forms a resonator between the high reflection film 12 and the equivalent reflection surface of each of the gratings 16-1, 16-2, 16-3, and 16-4, and each has a different wavelength λ _1. , Λ ₂ , λ ₃ , λ ₄ to each optical fiber 2
Output in the directions of 3-1, 23-2, 23-3, and 23-4. The separation grooves 28-1 to 28-3 have a function of reducing interference between the respective laser oscillation units.

The present invention is not limited to the above embodiment.
First, GaAs may be used for the substrate 1 to form a laser oscillation section in a 1.3 μm wavelength band. The lower cladding layer 2
The refractive index between the active layer 3 and the active layer 3 is 3.3.
Buffer layer having a value lower than 75 and higher than the refractive index 3.163 of the lower cladding layer 2 (refractive index 3.2 to 3.0.
3) may be provided. By providing this buffer layer, low polarization dependence can be obtained. The core layer 15 and the cladding layer 14-1 (14-
2) and the cladding layer 14-1 (14-
A buffer layer having a value higher than the refractive index of 2) and lower than the refractive index of the core layer 15 may be provided. By providing this buffer layer, it is possible to increase the degree of freedom in design in consideration of both the optical coupling characteristics with the laser oscillation unit 20 and the filter characteristics of the grating 16.

In FIGS. 6A and 6B, the number of arrays is four, but is not limited thereto.
The number can be increased to two or more such as 6, 32,.... The active layer 3 may have a multiple quantum well structure other than the bulk structure. For example, the active layer has a quantum well structure and a seven-period structure. If the wavelength band of light is 1.55 μm band,
The seven-period structure is a well layer (about 7 nm in thickness, InGaAs layer)
And a barrier layer (about 8 nm thick, InGaAsP layer).

According to the present invention, (1) the laser resonator length can be shortened and the modulation band can be increased by integrally forming the laser oscillation section and the waveguide grating section on the same substrate. be able to. As a result, a higher-speed signal can be transmitted.

(2) Since the laser oscillation section and the waveguide grating section can be optically coupled with high efficiency and low reflection, a larger laser output can be obtained. Also,
The side mode suppression ratio can be increased, and the occurrence of the kink phenomenon can be prevented.

(3) SiON, SiONH, Si ₃ N ₄ -based insulating material containing N and G
By using an insulating material containing eO ₂ , a change in the refractive index due to a temperature change can be reduced. As a result, laser light having a stable oscillation wavelength can be emitted.

(4) The connection between the waveguide grating and the optical fiber can be performed with high optical coupling efficiency.

(5) It is easy to configure a small, high-output, and stable multi-wavelength laser oscillator, and it can be applied as a multi-wavelength light source for wavelength division multiplexing communication.

(6) By forming the waveguide grating portion from a SiON, SiONH, or Si ₃ N ₄ based insulating material containing GeO ₂ , it is easy to form the grating, and the laser oscillation portion and the optical fiber Can also have a refractive index matching action.

[0066]

In summary, according to the present invention, the following excellent effects are exhibited.

It is possible to provide an active device integrated with a grating waveguide which can transmit a high-speed signal in a small size and does not generate a kink.

[Brief description of the drawings]

FIG. 1A is a front view of a back end face side of a laminate showing an embodiment of a grating waveguide integrated active device of the present invention, FIG. 1B is a cross-sectional view taken along line AA of FIG.
(C) is a front view of the front end face side of the laminate, (d) is (b)
FIG. 7 is a sectional view taken along line BB of FIG.

FIG. 2 is a characteristic diagram showing refractive index characteristics of materials of a cladding layer and a core layer used in a waveguide grating part of a grating waveguide integrated active device of the present invention.

FIG. 3 is a cross-sectional view showing a grating waveguide integrated type active device of the present invention in which an optical fiber is connected to a light emitting end.

FIG. 4A is a front view of a laminated body showing another embodiment of the grating waveguide-integrated active device according to the present invention, and FIG. 4B is a cross-sectional view taken along line CC of FIG. ,
(C) is a front view of the front end side of the laminate.

FIG. 5 is a cross-sectional view showing an optical device connected to the grating waveguide integrated active device of the present invention.

FIG. 6A is a side view on the rear end face side of the laser oscillation unit array of the grating waveguide integrated type active device of the present invention, and FIG. 6B is a top view of FIG.

FIG. 7 is an external perspective view showing a conventional example of an optical active device.

FIG. 8 is a schematic structural view showing a conventional example of a laser with a fiber grating.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 3 Active layer 12 High reflection film 14-1, 14-2 Cladding layer 15 Core layer 16 Grating 19 Laminate 20 Laser oscillation part 21 Waveguide grating part

Claims (12)

[Claims] 1. A lasing laminate having an active layer sandwiched between at least top and bottom cladding layers on an upper surface of a substrate;
A waveguide having a high-refractive-index insulating layer having a substantially rectangular cross-sectional shape having a low-refractive-index insulating layer formed at least on the outer periphery is provided adjacent to the active layer, and the active layer and the high-refractive-index layer are optically coupled to each other. A light reflection film is formed on the end face of the laser oscillation laminate opposite to the waveguide, and a grating is formed on the high refractive index insulating layer of the waveguide, and the laser oscillation laminate is When a forward current is injected, laser oscillation light of a desired wavelength determined by the equivalent reflection surface of the light reflection film and the grating is emitted from the end face of the waveguide opposite to the laser oscillation laminate. An active device integrated with a grating waveguide, characterized in that: 2. The grating waveguide-integrated active device according to claim 1, wherein each layer of the substrate and the lasing laminate is made of a compound semiconductor. 3. The grating waveguide-integrated active device according to claim 1, wherein the active layer has a slab shape or a substantially rectangular cross-sectional shape. 4. The active device integrated with a grating waveguide according to claim 1, wherein the high refractive index insulating layer contains GeO ₂ . 5. A slab-like lower cladding layer and an active layer having a slab-like or substantially rectangular cross-sectional shape are sequentially formed on an upper surface of a compound semiconductor substrate having an electrode on a lower surface, and an upper cladding layer is formed so as to cover the active layer. A contact layer and an upper electrode are sequentially formed on the upper clad layer to form a laminate, a high reflection film is formed on one end face of the laminate, and all of the other end face side of the laminate is provided. Of the compound semiconductor substrate and a part of the upper surface of the compound semiconductor substrate are removed to form a ladder-shaped laminate, and a slab-like low-refractive-index insulating layer is formed on the upper surface of the compound semiconductor substrate from which a part of the upper surface is removed. There is formed, one end surface of the high refractive index insulating layer of substantially rectangular cross-section containing GeO ₂ of high refractive index on the low refractive index dielectric layer is formed to mate with the active layer, the high Another low-refractive-index insulating layer is formed to cover the refractive index. When a forward current is injected between the upper electrode and the lower electrode of the active device in which the grating is formed on the high refractive index insulating layer, a waveguide is formed. A grating waveguide-integrated active device, wherein laser oscillation light determined by an equivalent reflection surface is emitted from the other end face of the waveguide. 6. The low-refractive-index insulating layer and the high-refractive-index insulating layer of the waveguide are formed of SiON, SiONH, Si containing nitrogen.
₃ N ₄ system grating waveguide integrated active device according to claim 5 in which one is used for. 7. The active device integrated with a grating waveguide according to claim 5, wherein one end face and the other end face of the laminate are formed obliquely at an angle of 10 ° or less. 8. The active device integrated with a grating waveguide according to claim 5, wherein an end face of the waveguide on a side from which the laser oscillation light is emitted is formed obliquely at an angle of 10 ° or less. . 9. The grating waveguide according to claim 5, wherein the active layer is formed such that its width or thickness is narrow or thin in a tapered shape near the end face on the waveguide side. Integrated active device. 10. The width of an insulating layer having a high refractive index of GeO ₂ having a substantially rectangular cross section and having a narrow tapered shape at the end face side of the waveguide on the side where laser oscillation light is emitted, or the refractive index is reduced. 10. The active device integrated with a grating waveguide according to claim 5, wherein the active device is formed so as to be gradually lowered. 11. The grating waveguide integrated type active device according to claim 5, wherein an optical fiber is coupled to an end face of said waveguide on a side from which laser oscillation light is emitted. 12. The grating waveguide integrated type active device is configured in an array, the resonator length of each laminated body is different, and the wavelength of laser oscillation light emitted from each waveguide is different. 12. The active device integrated with a grating waveguide according to any one of 11.