JP2005274927A - Photonic crystal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To output light beams within a waveguide surface, to reduce loss and the size, to realize high functionality for optically integrated circuits and to reduce cost in an optical multiplexer/demultiplexer, a wavelength variable filter and an optical switch in which photonic crystals are used. <P>SOLUTION: In a photonic crystal device that is provided with photonic crystals (1) in which a periodic structure having a two dimensional refractive index is provided in a wavelength order, a plurality of line defective type waveguides is provided in the photonic crystals (1). One (3) of the line defective type waveguides functions as an input waveguide having a light beam incident section on its end and another line defective type waveguide (4) functions as an output waveguide having a light beam emitting section on its end. A ring resonator (8) is provided between the input waveguide (3) and the output waveguide (4) by forming line defects into a ring shape or a polygonal shape. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photonic crystal device used for optical communication, and more particularly to an optical multiplexer / demultiplexer, a wavelength tunable filter, an optical switch, and the like.

  With the explosive increase in Internet traffic, there is a demand for an increase in transmission capacity in optical communications. In order to meet this demand, wavelength division multiplexing (WDM) is adopted, and ultra-high capacity exceeding 1 terabit / second is becoming possible at a commercial level. In the optical integrated circuit that constitutes a high-speed, large-capacity WDM system, an optical multiplexer / demultiplexer / tunable filter that extracts light of a predetermined wavelength from WDM light, or conversely adds light of a predetermined wavelength to WDM light, There is a need for an optical switch for performing packet processing at high speed. In these devices, high performance such as wide wavelength band and low loss, miniaturization and low cost are important.

  In recent years, photonic crystals have attracted attention as a key technology for realizing such an optical integrated circuit, and many research institutions have been actively researching both theoretical and experimental aspects. This photonic crystal has a structure in which the refractive index is modulated with a period of light wavelength order, and a photonic band gap (PBG) for light is formed in the crystal according to the solution of the Maxwell equation in the periodic field. Therefore, light having a frequency corresponding to PBG cannot propagate in any direction in the crystal. When a crystal defect is introduced into such a photonic crystal by an appropriate design, light having a frequency corresponding to PBG cannot exist in a place other than the defect, and thus the light is localized in the defect. By utilizing such a property, it becomes possible to realize light capture by point defects and optical waveguides by line defects.

  Strictly speaking, PBG is realized only by a three-dimensional photonic crystal, but the manufacturing process of the three-dimensional photonic crystal is extremely complicated and difficult. On the other hand, it is known that a certain degree of PBG effect appears even in a two-dimensional photonic crystal having no periodic structure in one direction. In general, in a two-dimensional photonic crystal, total reflection confinement due to a refractive index difference is used to confine light in a direction perpendicular to a two-dimensional plane. A structure in which a photonic crystal is formed in a waveguide core layer having a high refractive index and this photonic crystal is sandwiched between cladding layers having a low refractive index is called a two-dimensional photonic crystal slab structure. There are those manufactured on an insulator (SOI) substrate and those using a cladding layer as air (air bridge structure).

With a line defect type optical waveguide in a photonic crystal, light can be bent at a steep angle (for example, vertical) with low loss, which was difficult with a conventional optical waveguide. Non-Patent Document 1 shows that a photonic crystal is applied to an optical multiplexer / demultiplexer using such characteristics. As shown in FIG. 7, this optical multiplexer / demultiplexer introduces a point defect 46 in the vicinity of a line defect waveguide 45 provided in the photonic crystal 44 and propagates the wavelength λ ₁ in the line defect waveguide 45. _, λ ₂ ···, λ _i, the optical multiplexer surface output type for demultiplexing vertically only to substrate optical resonance satisfy a specific wavelength lambda _i having ones point defects 46 of the wavelength-multiplexed light of ... min It is a waver. In this optical multiplexer / demultiplexer, a light extraction rate of several tens of percent or more is realized in the 1550 nm band.
Susumu Noda, Alongkarn Chutinan and Masahiro Imada, `` Trapping and emission of photons by a single defect in a photonic bandgap structure '', Nature, Vol.407,5 October 2000, p.608-610

  However, since the optical multiplexer / demultiplexer described in Non-Patent Document 1 is a surface output type, it is difficult to handle the output light, and matching between the emitted beam pattern and the optical fiber is difficult. However, since it is not easy to guide light to be multiplexed / demultiplexed, it has been insufficient for realizing an optical integrated circuit in which optical devices having various functions are integrated.

  On the other hand, if the light can be extracted in the waveguide plane, the emitted light can be easily handled, and there is an advantage that the optical multiplexer / demultiplexer can be miniaturized. Therefore, in the present invention, in an optical multiplexer / demultiplexer using a photonic crystal, a wavelength tunable filter, and an optical switch, it is possible to output light within the waveguide plane, and the optical integrated circuit is reduced in size and reduced in loss. The purpose is to achieve higher functionality and lower costs.

  In order to achieve the above object, the present invention provides a photonic crystal device using a photonic crystal having a two-dimensional refractive index periodic structure in a wavelength order, wherein a line defect type waveguide is provided in the photonic crystal. One of the line defect type waveguides functions as an input waveguide having a light incident part at one end thereof, and the other of the line defect type waveguides is an output waveguide having a light output part at one end thereof. And a ring-shaped resonator in which a line defect is provided in an annular shape or a polygonal shape between the input waveguide and the output waveguide.

In general, the resonance conditions of a resonator are as follows: the resonance wavelength is λ ₀ , the resonator length is L,
λ ₀ = n _eff · L / m Equation (1)
In the case of a ring-shaped resonator, the length of the ring is the resonator length. Here, n _eff is the effective refractive index of the medium, and m is an arbitrary integer.

  By configuring the optical multiplexer / demultiplexer as described above, it is possible to propagate only light having a wavelength satisfying the resonance condition of the ring resonator to other waveguides among the wavelength multiplexed light that has propagated through one waveguide. Therefore, the multiplexed / demultiplexed light can be extracted in the waveguide surface. In addition, since the multiplexed / demultiplexed light is emitted from the end of the waveguide, the beam pattern is better than that of the conventional surface output type optical multiplexer / demultiplexer, and the matching with the optical fiber is also excellent.

Also, in general, the resonance frequency interval (FSR) of a ring resonator is
FSR = c ₀ / (N _eff · L) Formula (2)
It is represented by In the photonic crystal, a very small ring resonator can be realized by utilizing a line defect, and the resonator length L can be shortened. Therefore, by using a photonic crystal, a large FSR can be obtained, and a wide wavelength band optical multiplexer / demultiplexer or the like can be configured.

In the above photonic crystal device, when the photonic crystal is formed on an SOI substrate and the air hole rods are formed in a periodic arrangement, air / Si layer / SiO _{2 in} the SOI substrate Light confinement in a direction perpendicular to the waveguide direction can be performed using the refractive index difference.

  Further, if the photonic crystal is formed on a semiconductor substrate and formed by periodic arrangement of air hole rods, the difference in refractive index between the semiconductor multilayer films having different band gaps stacked on the semiconductor substrate. Can be used to confine light in a direction perpendicular to the waveguide direction.

Further, in the above photonic crystal device, assuming that an electrode for applying a voltage or current is provided to the photonic crystal, the effective refractive index of the photonic crystal is changed by the application of the voltage or current to the electrode. As a result, the resonance condition of the ring resonator is changed, and the functions of light switching and wavelength filtering can be provided. In order to obtain a change in refractive index, an electro-optic effect, an electroabsorption effect, a quantum confined stark effect (QCSE), a plasma effect, a free carrier absorption effect, or the like can be used. When the change in the resonant wavelength when the refractive index changes by Δn _eff is Δλ, Δλ / λ ₀ = Δn _eff / n _eff (3)
Holds.

  The above photonic crystal device can be formed monolithically on a semiconductor substrate together with a semiconductor laser or a semiconductor photodiode, thereby obtaining a high-performance and small-sized semiconductor photonic crystal integrated device having an optical multiplexing / demultiplexing function. Can do.

  According to the present invention, it is possible to realize a low-loss, wide-wavelength band, small-sized optical multiplexer / demultiplexer, wavelength tunable filter, and optical switch that can extract combined and demultiplexed light with a good beam pattern in the waveguide plane. Can do. In addition, a high-performance and small-sized semiconductor photonic crystal integrated device can be obtained using these, and a high-speed and large-capacity WDM system can be configured at low cost.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

A conceptual diagram of the photonic crystal device of the present invention is shown in FIG. Photonic crystal 1 is in the high refractive index medium M _H, a rod-shaped low refractive index medium M _L extending in a direction perpendicular to the paper surface, and the periodically arranged two-dimensionally periodic structure at the wavelength order of light Yes. Here, although the case where the minimum unit of the array is an equilateral triangle is shown, it may not be a strict equilateral triangle, and the minimum unit may be a square (or a substantially square). The photonic crystal 1 has line-defect type waveguides 3 and 4 in which regions having air hole rods missing from the arrangement are linearly provided with a predetermined width. Further, a line defect type ring resonator 8 is provided in a region sandwiched between the waveguides 3 and 4 in which a region in which the air hole rods are missing from the arrangement is formed in an annular shape. Here, the ring resonator 8 is formed in a hexagonal shape so as to follow the arrangement of the surrounding rods, and the length of the circumference of the hexagon is the resonator length. However, the shape of the ring resonator is not limited to a hexagon, and may be any shape as long as it is formed with a resonator length having the formula (1).

When wavelength multiplexed light of wavelengths λ ₁ , λ ₂ ,... Λ _n is incident on the incident end of _one waveguide 3, only the light of wavelength λ _{1 that} satisfies the resonance condition expressed by equation (1) is obtained. The light is demultiplexed into the other waveguide 4 via the ring-shaped resonator 8. By taking out the light of the wavelength lambda _i from the output end to the waveguide 4 can be used as a demultiplexer for outputting the photonic crystal 1 in the waveguide surfaces.

Note that the widths of the waveguides 3 and 4 are designed so that the waveguide width satisfies a condition in which light having wavelengths λ _{1 to} λ _n can propagate.

  In order to reduce the influence of light reflection at the input end of the waveguide 3 and the output end of the waveguide 4, it is desirable to provide a reflection film made of a dielectric or the like. Further, it is desirable to provide means for spot size conversion for coupling with an external optical fiber.

  In addition, in order for light to be exchanged between the waveguides 3 and 4 and the resonator 8, the waveguides 3 and 4 and the resonator 8 do not share a part thereof, and one or more rows of rods are interposed between them. It is necessary to have a grid. FIG. 1 shows a case where this grid row is one row. If the number of lattice rows is four or more, the loss of light increases due to the strong light confinement of the photonic crystal. Therefore, the number of lattice rows is preferably three or less.

  Also, assuming that electrodes (not shown) are provided above and below the ring-shaped resonator 8 (the direction in which the air hole rod extends is the vertical direction), a voltage or current is applied to the ring-shaped resonator 8. Thus, an electric field is applied to the ring-shaped resonator 8 or current or heat is injected, so that the refractive index can be changed. This change in the refractive index changes the resonator length of the ring-shaped resonator 8 according to the equation (1). Therefore, the refractive index is emitted from the waveguide 4 according to the applied voltage or applied current to the photonic crystal device. The wavelength λ of the light can be changed and functions as a wavelength tunable filter.

The number of waveguides is not limited to two as described above, and may be three or more. That is, a plurality of ring resonators and corresponding waveguides may be provided for one input waveguide in the photonic crystal. Such an example is shown in FIG. 2, the low refractive index medium M _L in during M _H high refractive index medium within the photonic crystal 1 which periodically arranged, the waveguide 3 and the waveguide 4-6 line defect type is formed. Line defect type ring resonators 8, 9 and 10 are formed between the waveguides 3 and 4, between the waveguides 3 and 5, and between the waveguides 3 and 6, respectively. These ring resonators 8, 9 and 10 are formed with resonator lengths such that the resonance wavelengths are λ ₁ , λ ₂ and λ ₃ according to the equation (1). 2 shows a case where the waveguide 3 is used as an input waveguide and the waveguides 4 to 6 are used as output waveguides. Conversely, the waveguides 4 to 6 are used as output waveguides and waveguides. 3 may be an input waveguide. The photonic crystal device, the wavelength lambda ₁ to [lambda] the wavelength lambda ₁ from a wavelength multiplexed light _n, extracting light of lambda ₂ and lambda _3, or wavelength lambda _1, lambda ₂ and lambda ₃ of the wavelength of light lambda ₁ to [lambda] _It functions as an optical multiplexer / demultiplexer added to the _n wavelength multiplexed light.

As Embodiment 1 of the present invention, an optical multiplexer / demultiplexer formed using an SOI substrate will be described. FIG. 3 is a perspective view illustrating the optical multiplexer / demultiplexer according to the first embodiment. The SOI substrate 20 is obtained by laminating a Si ₂ layer 22 having a thickness of about 3 μm and a Si layer 23 having a thickness of about 0.2 μm on a Si substrate 21. The air hole rods 24 perpendicular to the substrate surface are periodically arranged on the Si layer 23 with the equilateral triangle as a minimum unit, thereby forming a photonic crystal having a two-dimensional periodic structure in a plane parallel to the substrate. The lattice constant (distance from the center of the adjacent air hole) a of the photonic crystal is about 400 nm, and the diameter of the air hole rod 24 is about 220 nm. The air hole rod 24 can be formed by dry etching such as reactive ion etching (RIE) by performing patterning using electron beam lithography and a dielectric mask.

In the photonic crystal, the line defect type waveguides 25 and 26 in which the air hole rods are missing from the arrangement and the line defect type ring resonator 27 are formed. One end of one waveguide 25 to the input port _{P in.} One end of the other waveguide 26 is defined as an output port _Pout .

This photonic crystal has Si (refractive index n = 3.46) as a core layer in the direction perpendicular to the substrate surface of the SOI substrate 20, and SiO ₂ (n = 1.45) and air (n = It has a high refractive index difference optical confinement structure with 1) as a cladding.

Here, the widths of the waveguides 25 and 26 need to be appropriately designed according to the wavelength band of the light to be used. When light having a wavelength band of 1500 nm to 1600 nm is used, the width of the waveguides 25 and 26 is set to about 473 nm. Furthermore, by setting the resonator length L of the ring resonator 27 according to the equation (1) in consideration of the effective refractive index n _eff of the photonic crystal so that the resonance wavelength is 1550 nm, for example, the waveguide 25 is formed. Only light having a wavelength of 1550 nm from the propagating wavelength multiplexed light is demultiplexed into the waveguide 26 via the ring resonator 27 and taken _out from the output port Pout (drop function). It is also possible to make light having a wavelength of 1550 nm incident on one waveguide 25 and add it to the wavelength multiplexed light propagating through the other waveguide 26 (add function).

  This optical multiplexer / demultiplexer has an FSR of about 6.6 THz from Equation (2), and is an optical multiplexer / demultiplexer in a wide wavelength band. In addition, since the diameter of the ring resonator can be reduced to about 5 μm, it can be remarkably reduced in size without increasing the radiation loss as compared with the case where it is made of a conventional quartz-based material or semiconductor material.

  The optical multiplexer / demultiplexer of the present invention can be applied to light of other wavelength bands by appropriately setting the widths of the waveguides 25 and 26 and the resonator length of the ring resonator 27. .

As a second embodiment of the present invention, a photonic crystal device that is formed on a semiconductor substrate and can be used as a wavelength tunable filter whose output wavelength is selected by an applied voltage will be described. The wavelength band of the light used shall be 1500-1600 nm. FIG. 4 is a partial cross-sectional perspective view illustrating the wavelength tunable filter according to the second embodiment. Wavelength tunable filter 30 is constituted by a photonic crystal composed of a low refractive index medium M _L and the high refractive index medium M _H. The high refractive index medium _MH is formed on an n-InP substrate 31 with an n-InP lower cladding layer 32, a non-doped GaInAsP light confinement layer 33, a non-doped GaInAsP multiple quantum well active layer 34, a non-doped GaInAsP light confinement layer 35, and a non-doped InP thin film. In this structure, a layer (not shown), a p-InP upper clad layer 36, and a p-GaInAsP contact layer 37 are sequentially laminated. The non-doped GaInAsP multiple quantum well active layer 34 is designed so that the number of quantum wells is 10 and the emission wavelength of the quantum well is 1.45 μm.

The low refractive index medium M _L is formed as the diameter 210nm air holes rod drilled in the high refractive index medium M _H. These air holes are periodically arranged in the high refractive index medium _MH to form a two-dimensional periodic structure extending in a plane parallel to the substrate. The lattice constant (air hole arrangement period) a of the photonic crystal is 360 nm. The air hole rod can be formed by patterning using electron beam lithography and a dielectric mask, and by dry etching such as RIE. Line defect type waveguides 39 and 40 having a width of 413 nm and a line defect type ring resonator 41 are formed in the photonic crystal. The resonator length of the ring resonator 41 is designed according to the equation (1), and is 22.8 μm. The light confinement in the direction perpendicular to the substrate uses the refractive index confinement structure based on the above layer structure.

One end of one waveguide 39 to the input port _{P in.} One end of the other waveguide 40 is defined as an output port _Pout . The P _in and P _out, the dielectric reflective film having an appropriate reflectance is coated.

  An upper electrode 42 is formed on the upper surface of the photonic crystal, and a lower electrode 43 is formed on the lower surface. When a voltage is applied from the variable power supply 50 between the upper electrode 42 and the lower electrode 43, the refractive index changes due to QCSE in the non-doped GaInAsP multiple quantum well active layer 34, and the resonator length of the ring resonator 41 changes. For this reason, the wavelength of the light demultiplexed by the ring resonator 41 can be changed according to the voltage value, and wavelength filtering can be performed.

In the structure of this embodiment, the refractive index of the ring-shaped resonator 41 can be changed by about 0.2% at maximum by the electric field. Therefore, the wavelength tunable width of the wavelength tunable filter is about 3 nm for incident light in the 1500 nm band.
.

  The FSR of this photonic crystal device is about 3.9 THz from the equation (2), and functions as a wide wavelength band filter effective for light of a wavelength band of about 30 nm in terms of wavelength.

  By using a fixed power supply and a switch instead of the variable power supply 50 in the wavelength tunable filter 30 above, the photonic crystal device can be used as an optical switch or an optical modulator. Such an optical switch is shown in FIG. The optical switch 60 is provided with a fixed power supply 61 and a switch 62 arranged in series instead of the variable power supply 50 shown in FIG. 4, and the controller 63 controls the switch 62 to be turned on and off. When the switch 62 is on, a current flows from the upper electrode 42 to the lower electrode 43, a refractive index change occurs due to QCSE in the non-doped GaInAsP multiple quantum well active layer 34, and the wavelength of light satisfying the resonance condition of the ring resonator 41 is shifted. Therefore, the passage of light having a wavelength that can flow from the waveguide 39 to the waveguide 40 at the time of OFF is blocked. As a result, an optical switch that turns on and off light of a desired wavelength is realized. In the case of realizing an optical modulator, the signal that the control unit 63 instructs to turn on and off only needs to correspond to the modulation signal.

  When the wavelength of the incident light is set to another wavelength band, the emission wavelength of the multiple quantum well active layer may be designed in accordance with the wavelength band to be used.

Next, as Example 3, a photonic crystal integrated device in which the photonic crystal device of the present invention is monolithically integrated on the same semiconductor substrate together with a semiconductor laser will be described.

  FIG. 6 shows a schematic top view of this photonic crystal device. The photonic crystal integrated device 70 has a photonic crystal region 71, a semiconductor laser region 72, and a spot size conversion region 73 on a common semiconductor substrate.

  The photonic crystal region 71 can have the same structure as the photonic crystal device shown in the first embodiment. Alternatively, the wavelength tunable filter and the optical switch / optical modulator described in the second embodiment can be used. In the semiconductor laser region 72, a type of semiconductor laser that does not require the formation of a reflecting mirror by cleavage, such as a DFB laser or a DBR laser, is formed, and its active layer 74 is coaxial with the waveguide 39 in the photonic crystal region 71. It is arranged to make.

The spot size conversion region 73 has a vertically tapered or horizontal tapered waveguide 77 whose thickness or width changes gently in the propagation direction. The waveguide 77 is disposed so as to be coaxial with the waveguide 40 in the photonic crystal region 71. Although the spot size in the waveguide 40 of the photonic crystal region 71 is as small as 1 μm or less, it is converted into a spot size that can be coupled to a normal single mode fiber or the like by the spot size conversion region 73 and emitted from the output port _Pout .

As shown in FIG. 6, the photonic crystal integrated device 70 is arranged in the middle of transmission of wavelength multiplexed light of wavelengths λ _{1 to} λ _n , for example, and adds light of wavelength λ _i . Wavelength-multiplexed light is incident from the input port _{P in} the photonic crystal integrated device 70, the waveguide 40, through the waveguide 77 is emitted from the output port _{P out.} On the other hand, laser light having a wavelength λ _i enters the waveguide 39 of the photonic crystal region 71 from the semiconductor laser region 72. The laser light having the wavelength λ _i is demultiplexed into the waveguide 40 through the ring resonator 41 while propagating through the waveguide 39, and is emitted from the output port P _out through the waveguide 77 together with the wavelength multiplexed light. It will be.

  If a semiconductor photodiode is integrated instead of the semiconductor laser in the photonic crystal integrated device, a light receiving type having a function of extracting light of a specific wavelength from the wavelength multiplexed light and converting it into an electric signal. It becomes a semiconductor photonic crystal integrated device.

  The semiconductor laser integrated type or photodiode integrated type photonic crystal integrated device as shown in this embodiment may have a plurality of ring resonators as shown in FIG.

  Note that if the semiconductor laser or semiconductor photodiode integrated in this embodiment is configured using a photonic crystal having a waveguide type defect, a much smaller integrated photonic crystal device can be obtained.

1 is a conceptual diagram of a photonic crystal device according to an embodiment of the present invention. It is a conceptual diagram which shows the modification of the photonic crystal device which concerns on embodiment of this invention. 1 is a perspective view of an optical multiplexer / demultiplexer according to Embodiment 1 of the present invention. It is a fragmentary sectional perspective view of the wavelength tunable filter concerning Example 2 of the present invention. It is a fragmentary sectional perspective view of the optical switch which is another example of Example 2 of the present invention. It is a top schematic diagram of the photonic crystal integrated device which concerns on Example 3 of this invention. It is a conceptual diagram which shows the conventional optical multiplexer / demultiplexer.

Explanation of symbols

1 photonic crystal 3-7 waveguide 8-10 ring resonator 20 SOI substrate 21 Si substrate 22 SiO ₂ layer 23 Si layer 24 an air hole rods 25,26 waveguide 27 ring resonator 30 wavelength tunable filter 31 n- InP substrate 32 n-InP lower clad layer 33 Non-doped GaInAsP optical confinement layer 34 Non-doped GaInAsP multiple quantum well active layer 35 Non-doped GaInAsP optical confinement layer 36 p-InP upper clad layer 37 p-GaInAsP contact layer 39, 40 Waveguide 41 Ring shape Resonator 42 Upper electrode 43 Lower electrode 44 Photonic crystal 45 Line defect waveguide 46 Point defect 50 Variable power supply 60 Optical switch 61 Fixed power supply 62 Switch 63 Control unit 70 Photonic crystal integrated device 71 Photonic crystal region 72 Semiconductor laser region Band 73 region _{M H} high refractive index medium _{M L} low refractive index medium _{P in} the input port _{P out} output port

Claims (10)

In a photonic crystal device using a photonic crystal having a two-dimensional refractive index periodic structure in the wavelength order of light,
The photonic crystal has a plurality of line defect type waveguides,
One of the line defect type waveguides functions as an input waveguide having a light incident part at one end thereof,
The other line defect type waveguide functions as an output waveguide having a light emitting part at one end thereof,
A photonic crystal device comprising a ring-shaped resonator in which a line defect is provided in an annular shape or a polygonal shape between the input waveguide and the output waveguide. 2. The photonic crystal device according to claim 1, wherein the photonic crystal is formed on a silicon-on-insulator (SOI) substrate, and the air-hole rods are formed in a periodic arrangement. The photonic crystal device according to claim 1, wherein the photonic crystal is formed on a semiconductor substrate, and air hole rods perpendicular to the semiconductor substrate are formed in a periodic arrangement. 4. The photonic crystal device according to claim 2, wherein the periodic arrangement of the air hole rods has a substantially equilateral triangle as a minimum unit. 4. The photonic crystal device according to claim 2, wherein the periodic arrangement of the air hole rods has a substantially square as a minimum unit. 6. An electrode for applying a voltage or current to the photonic crystal is provided, and a resonance condition of the ring resonator is changed by applying a voltage or a current to the electrode. The photonic crystal device according to one item. The photonic crystal device according to claim 6,
A variable power source connected to the electrode;
And a wavelength tunable filter that filters light incident from the light incident portion. The photonic crystal device according to claim 6,
A power source connected to the electrode;
A switch for switching power supply from the power source to the photonic crystal device;
Means for performing switching control of the switch;
An optical switch / optical modulator comprising: turning on and off the light incident from the light incident portion. A semiconductor laser is monolithically formed on a semiconductor substrate together with any one of the photonic crystal device according to claim 6, the tunable filter according to claim 7, and the optical switch / optical modulator according to claim 8. A semiconductor photonic crystal integrated device. A semiconductor photodiode is monolithically formed on a semiconductor substrate together with any one of the photonic crystal device according to claim 6, the wavelength tunable filter according to claim 7, and the optical switch / optical modulator according to claim 8. A semiconductor photonic crystal integrated device.

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