JPH0561002A - Waveguide type optical isolator and optical circulator - Google Patents

Abstract

PURPOSE:To obtain the waveguide type optical isolator and optical circulator which is wide in wavelength range, small in size and stable is operation. CONSTITUTION:A waveguide 2 is formed on a substrate 1 and an electrode 3 for generating a TE/TM mode conversion by an electrooptical effect and an electrode 5 for making phase difference adjustment between both modes are formed. Metallic films 6 and 7 are formed as polarizers. Such substrate is disposed in a permanent magnet 11 of a hollow cylindrical shape. The optical isolator operating to preserve the polarized waves of incident light 8 by the synthesis of the TE/TM mode conversion of a magneto-optical effect and electrooptical effect and to emit all these waves by impression of a voltage to the electrodes 3 and 5 and to rotate the polarized waves of the return light 9 by 90 deg. and to shut off these weaves by the polarizers is constituted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical isolator and an optical circulator used for optical communication or optical information processing.

[0002]

2. Description of the Related Art With the practical use of optical communication and optical information processing using semiconductor lasers, transmission or storage of high density information is expected. In order to realize this, stabilization of the oscillation wavelength and intensity of the semiconductor laser is desired. In order to improve the reliability and stability of a semiconductor laser, an optical isolator that prevents the oscillation state from destabilizing due to returning light is essential.

The structure of the optical isolator includes a bulk type using a magneto-optical crystal, a thick film type in which a magneto-optical material is grown thick on a substrate, and a waveguide type using an optical waveguide. Among them, the waveguide type optical isolator is required for high-density optical communication and optical information processing because it operates in a compact and stable manner and can be integrated with optical elements such as semiconductor lasers, optical fibers and optical modulators. It becomes essential. As such a waveguide type optical isolator, there have been many reports of a configuration in which a nonreciprocal polarization rotation element (nonreciprocal mode converter) utilizing a magneto-optical effect (Faraday effect) and a polarizer are combined. The non-reciprocal polarization rotation element performs an operation in which the rotation direction of polarization is reversed depending on the traveling direction of light. Typical waveguide-type optical isolators are non-reciprocal polarization-rotating elements in which the polarization plane is rotated by 45 ° by adjusting the magnetic field or element length, and waveguide-type polarizers and waveguides in which a metal film is deposited on the waveguide. There is a configuration in which an external polarizer that passes polarized light polarized by 45 ° with respect to the surface of the substrate where is present is combined. In addition, it has been reported that a semiconductor laser is arranged at an angle of 45 ° with respect to the substrate surface instead of an externally attached polarizer. In addition, a reciprocal polarization rotation element (reciprocal mode converter) that uses the second-order magneto-optical effect (Cotton-Mouton effect) to rotate the polarization by 45 ° in the same direction as the traveling direction of light is used. A combination of reciprocal 45 ° polarization rotators, the light entering from one side does not rotate the polarization and the light entering from the other side
A waveguide-type optical isolator using a non-reciprocal polarization-rotating element that rotates by 90 ° polarization and two waveguide-type polarizers has also been proposed.

[0004]

In the waveguide type optical isolator using the externally attached polarizer, the size of the element is increased because the polarizer for transmitting 45 ° polarized wave is externally attached. Furthermore, since an optical system such as a lens is used for coupling with the optical fiber,
It requires precise adjustment of the optical axis. Further, it is difficult to finely adjust the passing polarization plane to 45 °. For example, in order to obtain optical isolation of 30 dB or more, it is necessary to set the deflection angle of the polarizer within 45 ° ± 1 °. Similarly, it is difficult to adjust the angle when the semiconductor laser is arranged at an angle of 45 ° with respect to the waveguide isolator substrate surface. In addition, the loss of light is large at the coupling part between the semiconductor laser and the waveguide type optical isolator, and if an optical system such as a lens or an optical fiber is used for coupling between both elements in order to reduce the loss, the size of the element becomes large. There is a drawback that

In a waveguide type optical isolator utilizing the Faraday effect and the Cotton-Mouton effect, the direction of application of the magnetic field inducing each effect and the magnetic field strength required for 45 ° polarization rotation are different. Require two different magnetic fields. In this case, since it is impossible to strictly separate the regions to which the two magnetic fields are applied, it is difficult to control each effect independently so that sufficient optical isolation can be obtained. Furthermore, the size of the element is increased because two magnets having different applied magnetic field directions are required. Further, the method of synthesizing and applying two magnetic fields has a drawback that the element length becomes long.

As described above, the conventional waveguide type optical isolator has a drawback that various fine adjustments are required to obtain sufficient optical isolation. Furthermore, since an optical element such as a lens and two magnets are required, it is unavoidable that the element becomes large in size, which is not suitable for integration with an optical element such as a semiconductor laser or an optical modulator.

Further, most optical circulators have been developed, which are considered to be applied to optical pickups of compact disc players and compact disc memory devices and used as devices constituting high-quality and high-density optical communication systems. Not not.

[0008]

The waveguide type optical isolator of the present invention is constructed by using a material having both an electro-optical effect and a magneto-optical effect, and using both the electro-optical effect and the magneto-optical effect. And a waveguide-type polarization rotator, and at least one waveguide-type polarizer.

Further, the waveguide type optical circulator of the present invention uses a material having both an electro-optic effect and a magneto-optic effect, and is constructed using both the electro-optic effect and the magneto-optic effect. It is characterized in that it is provided with a wave rotation element and two waveguide type polarization splitters, and the waveguide type polarization rotation element is interposed between the two waveguide type polarization splitters.

[0010]

According to the structure of the waveguide type optical isolator or the optical circulator of the present invention, the polarization plane is not rotated for the light incident from a certain direction, and the light incident from the opposite direction is polarized by 90 °. The non-reciprocal polarization rotator, which has the function of rotating and emitting the wavefront, and the polarizer or the polarization separator are integrated in the waveguide, so it is a compact type that does not require adjustment of the optical axis. Performs stable operation. further,
Since two different fields, an electric field and a magnetic field, are used, control for obtaining sufficient optical isolation is easy.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a waveguide type optical isolator of the present invention. The waveguide 2 is formed along the [112] axis (z axis in FIG. 1A) on the (111) plane of the substrate 1 of the zinc blende structure semiconductor having the magneto-optical effect and the electro-optical effect.
To form. The method of manufacturing the waveguide will be described later. The electrode 3 is formed next to the waveguide so that an electric field is applied in the [110] axis direction (the y axis direction in FIG. 1B). After forming the insulating film 4 on the waveguide, the electrode 5 is formed on the insulating film 4 and the back surface of the substrate 1. Furthermore, the metal film 6 that plays the role of a polarizer
And 7 are formed on the waveguide. Next, as shown in FIG. 1B, the polarization maintaining fiber 10 is connected to the end face of the waveguide, and the waveguide type optical isolator shown in FIG. The operation will be described below. Figure 1 (a)
Consider the case where the light 8 whose polarization plane (electric field component of light) is in the y direction is incident as described above. The waveguide loaded with the metal film 6 becomes a waveguide-type polarizer that allows only the TE mode having an electric field component in the y direction to pass therethrough, so that all the guided light excited by the incident light 8 passes through. The magneto-optical effect is generated by the magnetic field applied from the permanent magnet 11, and mode conversion occurs from the TE mode to the TM mode having the main electric field component of light in the x direction. Here, the polarization plane synthesized in the TE / TM mode of the guided light incident on the waveguide type polarizer loaded with the metal film 7 is rotated by 45 ° clockwise with respect to the traveling direction z of the light wave. Set the direction and strength. On the other hand, when an electric field is applied from the electrode 3 in the [110] axis direction (x direction in FIG. 1A) of the zinc blende structure, mode conversion due to the electro-optical effect occurs. In general, since the light whose mode is converted by the electro-optical effect becomes elliptical polarized wave, an electric field is applied by the electrode 5 in the [111] axis direction (x direction in FIG. 1A), and the TE / TM mode is generated by the electro-optical effect. To give arbitrary linearly polarized waves. The polarization plane of the guided light that enters the voltage applied to the electrode 3 required for the mode conversion and the voltage applied to the electrode 5 required for the phase adjustment to the waveguide type polarizer loaded with the metal film 7 in the traveling direction z of the light wave is Adjust so that it rotates counterclockwise at 45 °. The rotation of the polarization due to the magneto-optical effect and the rotation of the polarization due to the electro-optical effect are opposite and the rotation angles are equal, so that the rotation of the polarization is canceled. Therefore, the polarization of the guided light incident on the waveguide polarizer loaded with the metal film 7 is equal to the polarization of the incident light 8 and is in the TE mode. Since the TE mode passes through the waveguide type polarizer loaded with the metal film 7, all the incident light 8 is emitted. Next, consider the return light 9 incident from the opposite direction. Only the TE mode of the excited guided light passes through the waveguide polarizer loaded with the metal film 7. The polarization plane of the guided light is rotated by 45 ° counterclockwise with respect to the traveling direction −z of the light wave by the electric field applied to the electrodes 3 and 5. That is, when viewed from the z direction, it rotates 45 ° clockwise. In this case, the light wave traveling in the −z direction first passes through the phase adjustment electrode 5. Since only the TE mode passes through the waveguide type polarizer loaded with the metal film 7,
It seems that the phase difference adjustment between the TM modes is not effective, but since the TM mode generated by the mode conversion due to the magneto-optical effect exists in the waveguide in the region below the phase adjustment electrode 5, the ellipse is obtained by the phase adjustment. It becomes polarized wave and is effective for mode conversion by the electro-optic effect. On the other hand, since the magneto-optical effect does not depend on the traveling direction of the light wave but on the application direction of the magnetic field, the plane of polarization rotates 45 ° clockwise with respect to the z direction. Therefore, the polarization plane is 90 due to the electro-optic effect and the magneto-optic effect.
It is rotated by ° and converted to TM mode. In the TM mode, the return light 9 is not emitted because it does not pass through the waveguide polarizer loaded with the metal film 6. From the above, it can be seen that it operates as an optical isolator. Although the polarizer made of a metal film is used in this embodiment, a polarizer made of a multilayer film of a metal film and a dielectric film may be used. In this case, the polarized wave passing through is TM mode. Further, the (001) plane is used instead of the (111) plane, a waveguide is formed along the [110] axis direction in the (001) plane, and the waveguide is orthogonal to the [11] plane.
When an electric field is applied in the [0] axis direction and the [001] axis direction,
The electro-optic effect causes mode conversion and phase change between modes. Therefore, if a magnetic field is applied in the waveguide direction ([110] axis direction), the configuration using the (001) plane also operates as an optical isolator.

FIG. 2 is a diagram showing the configuration of the waveguide type optical circulator of the present invention. A waveguide-type polarization splitter 1 in which a metal film 14 is loaded on one waveguide of a directional coupler instead of the metal films 6 and 7 serving as the polarizers of the waveguide-type optical isolator.
2 and 13 are used. In this waveguide type polarization separator, only the TE mode propagates in the waveguide loaded with the metal film 14, and only the TM mode propagates in the waveguide loaded with no metal film. The operation of the optical circulator will be described below with reference to FIG. The non-reciprocal polarization rotation caused by the electro-optic effect and the magneto-optic effect is the same as that of the waveguide type optical isolator. Light for exciting the TM mode is incident from the terminal 15. Since the polarization rotation due to the electro-optic effect and the magneto-optic effect is canceled for the light wave propagating in the z direction, the waveguide light is not transferred in the polarization separator 13 and propagates to the waveguide not loaded with the metal film. Then, the light is emitted from the terminal 16. T incident from terminal 16
Since the M mode propagates in the −z direction, it is converted to the TE mode by the polarization rotation element. TE mode is polarization splitter 12
Since it propagates through the waveguide loaded with the metal film of
Emit from 7. Similarly, since the TE mode incident from the terminal 17 does not rotate the polarization, the polarization separator 13 propagates through the waveguide loaded with the metal film and is emitted from the terminal 18 and then the terminal 1
The TE mode incident from 8 is converted into the TM mode by polarization rotation and is emitted from the terminal 15 by the polarization separator 12. Therefore, the incident light and the outgoing light are transmitted from the terminal 15 to the terminal 16
It can be seen that it operates as an optical circulator that circulates in the order of: terminal 17 → terminal 18 → terminal 15. In this embodiment, a directional coupler in which a metal film is loaded on one of the waveguides is used as the polarization splitter, but a polarization film in which a metal film is loaded on one of the Y-branch waveguides is used. Even if a wave separator is used, it similarly operates as an optical circulator.

In the waveguide type optical isolator and the optical circulator described above, it is important to form a single mode waveguide in order to completely rotate the returned light propagating in the -z direction by 90 °. In addition, since there is no need to perform 100% mode conversion for each of the electro-optical effect and the magneto-optical effect, TE / T
It is not necessary to strictly match the propagation constants of the M mode, and there are few problems in producing the waveguide.

Next, a method of forming channel waveguides for some substrate materials will be described. The shapes of the waveguides described here are the ribbed waveguide shown in FIG. 3A and the buried waveguide shown in FIG. 3B.

_First , a method of forming a Cd _1-x Mn _x Te waveguide that is transparent in the visible region and has a large Faraday effect will be described. In the case of the rib type waveguide of FIG.
Cd _{1- y} Mn _y Te (where 0 ≦ y ≦ 1) is used, and Cd _1-x Mn _x Te (where 0 ≦ x ≦ 1. There is). Here, in order to form the waveguide, the refractive index of the waveguide layer 19 needs to be larger than that of the substrate 1. Since the smaller the Mn content, the larger the refractive index, it is necessary to set x <y. Waveguide layer 19
After forming the film to be formed, the resist, the metal film, or the dielectric film is linearly patterned to form a protective film, which is then etched. After etching, the rib portion 20 is formed by removing the protective film. However, in this case, the Faraday rotation angle becomes smaller as the Mn content decreases, so that the Faraday rotation angle of the waveguide layer 19 becomes smaller than that of the substrate 1.

Next, a method of forming the buried waveguide shown in FIG. 3B will be described. For the substrate 1, p-type Cd _1-x Mn _x Te is used. In is deposited or sputtered and deposited on the substrate 1,
It is patterned linearly by photolithography.
Cd _1-x Mn _x Te loaded with In is heated to 400 ° C. in a nitrogen atmosphere to cause In to undergo solid phase diffusion. In diffusion region 21 is n-type Cd
_{Since it is 1-x} Mn _x Te: In, a pn junction is formed with the substrate. Since the free carrier density decreases in the depletion layer of the pn junction, the refractive index of the diffusion region 21 becomes higher than that of the substrate 1. Therefore, a waveguide can be formed. In this case, unlike the rib waveguide, the Mn content does not change, so that a large Faraday rotation angle can be efficiently obtained.

Next, a description will be given of a method of forming a ZnSe waveguide, in which a lattice constant is almost matched with a GaAs substrate and a high quality film with few defects can be obtained by epitaxial growth. Generally, in the II-VI group semiconductor, the larger the atomic weight of the II group or VI group element, the higher the refractive index. Therefore, FIG.
When forming a rib-shaped waveguide like the above, first, the substrate 1
On top of ZnSe, Zn _1-x Cd _x Se, ZnSe _1-x Te _x or Zn _1-x Cd _x
A mixed crystal film of Se _1-y Te _y is grown as the waveguide layer 19. Next, the rib portion 20 is produced by etching in the same manner as described above. In the case of the embedded waveguide shown in FIG. 3B, the ZnSe of the substrate 1 is covered with a high melting point material such as fused quartz having a low reactivity with ZnSe, and a linear gap is formed by etching or lift-off method. , ZnSe substrate 1 is exposed. Next, when the substrate and Cd or Te are put in a quartz tube, the chamber is evacuated to vacuum, sealed and heated at 800 ° C., gas phase diffusion of Cd or Te occurs. As a result, a solid solution of CdZnTe or ZnSeTe is generated in the diffusion region 21, so that the refractive index is increased and it becomes a waveguide.

Finally, a material Bi ₁₂ SiO which can be epitaxially grown on sapphire or lithium niobate (LiNbO ₃ , LN) which is often used as a substrate for an optical deflector or an optical modulator and which can be integrated with the above device. We describe a method of forming a waveguide using ₂₀ (BSO) or Bi ₁₂ GeO ₂₀ (BGO). In FIG. 3 (a), BSO or BGO is epitaxially grown on the sapphire substrate 1 or LN substrate 1 by a sputtering method or the like, and a protective film of a metal film or a dielectric film is linearly patterned and then etched to remove the protective film. To obtain a rib waveguide.

The applied voltage and magnetic field required for the waveguide type optical isolator (FIG. 1) produced using the above materials are shown below. Here, in order to manufacture a single mode waveguide, the waveguide width is set to 4 μm, and the difference in the refractive index between the substrate 1 and the surface of the waveguide layer 19 or the diffusion region 21 is set to
It was set to 0.3%. The total element length is 15 mm, and the lengths of the metal films 6 and 7 on the waveguide required to form the polarizer are 2.5 mm. In a waveguide loaded with a metal film as a polarizer, a permanent magnet 11 is used so that a magnetic field is not applied.
Alternatively, adjust the length of the electromagnet. Therefore, the length of the waveguide in which the magneto-optical effect occurs is 10 mm. Also, the length of the electrode 3 for causing mode conversion is 5 mm, and the interval is 10 μm.
m, and the length of the electrode 5 for adjusting the phase between modes is 5 mm. Figure 3 (b) with Cd _0.23 Mn _0.77 Te as the substrate
A case will be described in which light having a wavelength of 0.8 μm is incident on the embedded waveguide as described above. The voltage applied from the electro-optic coefficient to the electrode 3 required for mode conversion (hereinafter referred to as the mode conversion voltage) is 4.0V, and the voltage required to adjust the phase between the modes to the electrode 5 (hereinafter referred to as the phase adjustment voltage) is 3.8V. is there. However,
The voltage generated by the electrode 5 is applied to the depletion layer region of the pn junction formed by the n-type waveguide and the p-type substrate. From the Verdet constant, the magnetic flux density of the applied magnetic field required for mode conversion by the magneto-optical effect (hereinafter referred to as mode conversion magnetic flux density) is 0.03T. When the Mn content increases, the mode conversion magnetic flux density decreases, but the mode conversion voltage and the phase adjustment voltage remain almost unchanged. Further, even in the rib-shaped waveguide of FIG. 3A, the voltage and the magnetic flux density hardly change when the waveguide layer material is the same.

The voltage and the magnetic flux density to be an optical isolator when light with a wavelength of 0.63 μm is incident on the buried waveguide shown in FIG. 3 (b) in which Cd is diffused in ZnSe will be described. The mode conversion voltage is 11V and the phase adjustment voltage is 10V.
In this case, the phase adjustment voltage is a MIS (Metal Insulator Semiconductor) composed of the electrode 5, the dielectric 4 and the substrate 1.
Applied to the depletion region of the structure. The mode conversion magnetic flux density is
Requires 0.67T.

A case will be described in which a light having a wavelength of 0.63 μm is incident on a rib type waveguide formed by growing BSO on a sapphire substrate. BSO and BGO are not zinc blende crystals, but the electro-optic coefficient tensor forms are similar to those of zinc blende crystals. Therefore, by selecting the crystal plane that forms the waveguide and the crystal axis that applies the electric field, a waveguide type optical isolator similar to that shown in FIG. 1A can be constructed. In this case, the mode conversion voltage is 4.6V. When the thickness of the sapphire substrate is 0.5 mm, the phase matching voltage is 22V. The phase matching voltage can be reduced by forming the ground electrode on the back surface of the substrate on the BSO in parallel with the electrode 5. In addition, when the y-plate LN substrate is used, it is possible to use the electro-optic coefficient of LN for mode conversion by the electro-optic effect and phase adjustment between modes, and the mode conversion voltage and phase adjustment voltage can be significantly increased. It can be reduced. The mode conversion magnetic flux density is 0.8T.

When ZnSe and BSO are used, the required magnetic flux density increases, but a sufficient magnetic field can be applied if a superconducting coil is used instead of the permanent magnet. Also, the element length to which a magnetic field is applied is 1 mm, and the lengths of electrodes 3 and 5 are 0.5 mm, respectively.
In the case of mm, the mode conversion voltage, the phase adjustment voltage, and the mode conversion magnetic flux density require 10 times the respective values.

Finally, an embodiment of an optical isolator integrated with a semiconductor laser will be described with reference to FIG. Ga
N-AlGaAsP layer 23 was grown on the As substrate 22 and the n ^- -GaAsP
Active layer 24, p-AlGaAsP layer 25 and p ⁺ -AlGaAsP layer 26 of
A semiconductor laser composed of is manufactured. The GaAs substrate 22 is exposed by selective etching so that the element length necessary for laser oscillation remains. MnTe on the exposed GaAs substrate 22
The film 27 is crystal-grown by the molecular beam epitaxial method. A Cd _1-x Mn _x Te film 28 is grown on the MnTe film 27,
_A linear waveguide is formed by the same procedure as the method for manufacturing a _1-x Mn _x Te rib waveguide. At this time, the MnTe film 27 and the Cd _1-x Mn _x Te film 2
The film thickness of 8 is set so that the light emitted from the n ⁻ -AlGaAsP active layer 24 is coupled to almost 100% of the Cd _{1 −x} Mn _x Te waveguide. However, the film thickness of the Cd _1-x Mn _x Te film 28 satisfies the condition that the waveguide has a single mode, and the film thickness of the MnTe film 27 is the leaching of the field distribution of the waveguide mode into the GaAs substrate 22. Must be satisfied. A gap 29 between the semiconductor laser and the CdMnTe film 28 is formed by reactive ion etching or the like,
Make a mirror finish. The mode conversion electrode 3 is formed along the Cd _1-x Mn _x Te waveguide, and the phase adjustment electrode 5 is formed on the dielectric film 4 such as SiO ₂ deposited on a part of the waveguide. The polarizer metal film 7 is deposited on the emission side. The reason for configuring the polarizer only on the output side is that the output light of the semiconductor laser is practically linearly polarized light, and the output of the light wave having the polarization orthogonal to this plane of polarization is 20 dB or less of the output light wave. Furthermore, even if the return light having a polarization orthogonal to the plane of polarization of the emitted light returns to the semiconductor laser, it hardly affects the oscillation characteristics. Finally, the back surface of the GaAs substrate 22 and the p ⁺ -AlGaAsP layer 2
The electrode 30 is formed on the electrode 6. From the above, an optical isolator integrated semiconductor laser can be constructed. Although the short wavelength semiconductor laser made of AlGaAsP deposited on the GaAs substrate is used here, the InGaAsP long wavelength semiconductor laser on the InP substrate and the optical isolator can be integrated. In the case of integrating with a distributed feedback semiconductor laser or a Bragg reflection type semiconductor laser, a gap 29 between the semiconductor laser and the optical isolator needs to be provided if the length of the diffraction grating required for light wave feedback is sufficient. In addition, it is possible to prevent a decrease in light intensity due to scattering or reflection on the gap surface. Further, instead of the optical isolator, a semiconductor laser in which an optical circulator is integrated can be constructed by the same procedure. Further, a semiconductor laser integrated optical pickup can be constructed by integrating a photodetector with the waveguide through which the return light is emitted.

[0024]

The waveguide type optical isolator and the optical circulator of the present invention have a new structure which uses both the electro-optical effect and the magneto-optical effect. It is possible to integrate and use a polarizer or a waveguide type polarization separator, and it is possible to downsize the element.

Further, the adjustment of the optical axis is unnecessary, and the optical axis does not shift due to environmental changes such as temperature or shock.

Further, even if the element length and the electrode length deviate from the designed values, the return light can be sufficiently blocked by adjusting the applied electric field and the applied magnetic field with almost no attenuation of the intensity of the passing light. ..

Further, by using a II-VI group semiconductor such as Cd _1-x Mn _x Te, it can be integrated with a semiconductor laser. If BSO or BGO is used, a waveguide type optical deflector on a dielectric substrate can be used. Since it can be integrated with the waveguide type optical modulator, it is possible to provide an optical isolator or an optical circulator integrated type optical element which does not require adjustment of the optical axis and can stably operate.

[Brief description of drawings]

FIG. 1A is a perspective view showing the arrangement of a waveguide and a polarizer, the direction of application of an electric field, and the rotation direction of a plane of polarization in the configuration of a waveguide type optical isolator according to an embodiment of the present invention. The figure which shows the application direction of a magnetic field and the coupling | bonding with an optical fiber in the structure of the waveguide type optical isolator in an Example.

FIG. 2 is a configuration diagram of a waveguide type optical circulator in an embodiment of the present invention.

FIG. 3A is a diagram showing a shape of a rib waveguide used in an embodiment of the present invention, and FIG. 3B is a diagram showing a shape of a buried waveguide used in an embodiment of the present invention.

FIG. 4 is a sectional view of a waveguide type optical isolator integrated semiconductor laser of the present invention.

[Explanation of symbols]

1 substrate 2 waveguide 3 electrode 4 insulating film 5 electrode 6 metal film 7 metal film 8 incident light 9 return light 10 optical fiber 11 permanent magnet 12 polarization separator 13 polarization separator 14 metal film 15 terminal 1 16 terminal 2 17 Terminal 3 18 Terminal 4 19 Waveguide layer film 20 Rib 21 Diffusion region 22 GaAs substrate 23 n-AlGaAsP layer 24 n ^-- AlGaAsP active layer 25 p-AlGaAsP layer 26 p ⁺ -AlGaAsP layer 27 MnTe film 28 Cd _{1- x} Mn _x Te film 29 Gap 30 Electrode

Claims (7)

[Claims] 1. A waveguide type polarization rotation element configured by using both the electro-optic effect and the magneto-optic effect by using a material having both the electro-optic effect and the magneto-optic effect, and at least one conductor. A waveguide type optical isolator comprising a corrugated polarizer. 2. A waveguide type polarization rotator is provided on a (111) plane of a zinc-blende semiconductor in which a group II-VI compound semiconductor or a group II element of the semiconductor is partially or entirely replaced by manganese [112]. A waveguide is formed along the axis, a magnetic field is applied in the [112] axis direction, and an electric field is applied in the [110] axis direction and the [111] axis direction. The waveguide type optical isolator described. 3. A waveguide type polarization rotator and a waveguide type polarizer are provided as Cd.
Characterized in that an optical waveguide formed by diffusing In from a p-type Cd _1-x Mn _x Te (where 0 ≦ x ≦ 1) surface in which is partially or wholly replaced by Mn is used The waveguide type optical isolator according to claim 1. 4. A waveguide type polarization rotator comprising a material having both an electro-optical effect and a magneto-optical effect and using both the electro-optical effect and the magneto-optical effect, and 2.
A waveguide-type optical circulator comprising: two waveguide-type polarization splitters, wherein the waveguide-type polarization rotation element is interposed between the two waveguide-type polarization splitters. 5. A waveguide type polarization rotator is provided in the (111) plane of a zinc-blende semiconductor in which a group II-VI compound semiconductor or a group II element of the semiconductor is partially or entirely replaced by manganese [112]. The waveguide is formed along the axis, a magnetic field is applied in the [112] axis direction, and an electric field is applied in the [110] axis direction and the [111] axis direction. The waveguide type optical circulator described. 6. A p-type Cd _1-x Mn _x Te in which Cd is partially or entirely replaced by Mn in the waveguide type polarization rotator and the waveguide type polarization separator.
The waveguide type optical circulator according to claim 4 or 5, wherein an optical waveguide formed by diffusing In from a surface (where 0≤x≤1) is used. 7. A waveguide type optical isolator according to any one of claims 1 to 3, and a semiconductor laser comprising at least one group III element and at least one group V element on a GaAs or InP substrate. A semiconductor laser device in which the waveguide type optical circulator according to any one of 4 to 6 is integrated.