JP4052082B2 - Demultiplexer and optical switching device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a demultiplexer that demultiplexes an optical signal that has been frequency multiplexed (wavelength multiplexed) in optical frequency division multiplexing (optical wavelength division multiplexing), and an optical switching device using the same.
[0002]
[Prior art]
With the recent increase in Internet traffic, optical communication is required to increase in speed and capacity. In general, the high-density wavelength division multiplexing (DWDM) technology used as a technology for realizing a large capacity of optical communication combines light in which a plurality of wavelengths are multiplexed in a specific wavelength band at a certain node. The light is multiplexed by a multiplexer and transmitted through one optical fiber, and the light is demultiplexed by a demultiplexer at a receiving node. The light demultiplexed at the receiving node is subjected to routing, switching, and the like, and is distributed for each destination.
[0003]
Node configurations such as OXC (Optical cross connect) and OADM (Optical add-drop multiplexer), which are responsible for such functions as demultiplexing, multiplexing, switching, and routing, have the performance, demultiplexer, Various configurations have been proposed in consideration of specifications (losses, etc.) of elemental technologies such as switches and their costs. Among them, a transparent optical cross connect (Transparent OXC) device having a hierarchical structure in which an optical switch that performs switching in units of wavelength bands and an electrical switch that performs wavelength conversion has been attracting attention recently.
[0004]
FIG. 34 is a diagram illustrating a general configuration of a transparent OXC apparatus. Referring to FIG. 34, the transparent OXC apparatus has a hierarchical configuration in which an optical switch (wavelength band switch) 102 that performs switching in wavelength band units and an electrical switch 103 that performs wavelength conversion are merged. The optical switch 102 is switched in wavelength units or wavelength band units. The optical switch 102 does not have a wavelength conversion function. A client device 105 is connected to an add-drop port of the optical switch 102 via an electrical switch 103 or a transponder that performs 3R regenerative relay.
[0005]
By adopting such a hierarchical configuration, only signals that drop to the client device 105 and signals that are added from the client device 105 are signals that pass through the node via the opaque switch port. Since switching can be performed without intermediating the opaque (OEO) switch port, it is not necessary to prepare an opaque (OEO) switch that is expensive in terms of the total number of ports, and cost reduction can be achieved. There are benefits.
[0006]
In the transparent OXC apparatus, the demultiplexer (filter) 104 has a function of dividing the wavelength-multiplexed optical signal into a plurality of wavelength bands, and is divided into several types according to the division method.
[0007]
The interleaver shown in FIG. 35 is also called a “wavelength splitter”, and divides a plurality of wavelengths into two separate wavelength groups as shown in FIG. Regarding the interleaver, the following documents are referred to (for example, Patent Documents 1 and 2).
[0008]
[Patent Document 1]
U.S. Patent 6,130,971
[Patent Document 2]
U.S. Patent 6,208,444
[0009]
36, a top-flat (AWG) circuit divides a certain number of wavelengths (two in FIG. 36) into a plurality of wavelength bands, as shown in FIG. For example, the following documents are referred to.
[0010]
[Non-Patent Document 1]
K. Okamoto, et al., “Flat spectral response arrayed-waveguide grating multiplexer with parabolic waveguide horns” Electoron. Lett., Vol 32 No. 18 pp.1661-1662, August 1996.
[0011]
The band filter shown in FIG. 37 is divided into two wavelength bands, a short wavelength side and a long wavelength side, as shown.
[0012]
Note that the AWG is not only a top-flat type whose transmission band profile is close to a rectangle, but a Gaussian AWG whose transmission band profile is a Gaussian type can also be used according to the specifications of the apparatus. Regarding AWG, for example, the following documents are referred to.
[0013]
[Non-Patent Document 2]
H. Takahashi, et al., “Arrayed-waveguide grating for wavelength division multi / demultiplexer with nanometre resolution” Electoron. Lett., Vol 26 No. 2 pp.87-88, 1990.
[0014]
As described above, the demultiplexer 104 used in the transparent OXC apparatus of FIG. 34 has various forms. Usually, the required performance of the node apparatus, the specifications such as the loss of each demultiplexer, the cost, etc. Is selected in consideration.
[0015]
[Problems to be solved by the invention]
However, in the conventional duplexer as described above, the wavelength bandwidth is unique to the duplexer in any duplexer, and changing the wavelength bandwidth is not limited to any duplexer. Impossible. For example, as shown in FIG. 38, when a demultiplexer that divides eight wavelength-multiplexed wavelengths λ1 to λ8 into four passbands, two from the low wavelength side, is illustrated. The four pass bands from (BAND1) to band 4 (BAND4) are switched by the optical switch 102 (see FIG. 34) and output to any of the four fibers 1 (fiber1) to fiber 4 (fiber4). However, the wavelength (group) output to any of the four fibers has its passband determined by the unique passband of the duplexer 104 (see FIG. 34).
[0016]
That is, since it is impossible to change the pass band, for example, as shown in FIG. 39, the bands 1 and 2 are the same as FIG. 38, but the band 3 is reduced and the band 4 is enlarged. It is impossible to demultiplex such that the selection wavelength of band 3 is changed to one and the selection wavelength of band 4 is changed to four. This is currently hindering the flexible and efficient operation of the network.
[0017]
If a limited wavelength band (the entire wavelength band from λ1 to λ8 in FIG. 38 and FIG. 39) is divided into a plurality of wavelength passbands, the bands carried by the plurality of passbands can be arbitrarily selected. If, for example, it is possible to arbitrarily change the passband setting shown in FIG. 38 to the passband setting shown in FIG. 39 or vice versa, a limited wavelength band can be set. Flexible and efficient network operation that can be changed flexibly according to the demand of the output destination is possible, which is very advantageous in terms of cost.
[0018]
Furthermore, if the bandwidth of a plurality of wavelength passbands after demultiplexing and the center wavelength of the wavelength passband can be controlled independently, it is further advantageous from the viewpoint of network operation.
[0019]
Therefore, the main object of the present invention is to make it possible to arbitrarily set a wavelength passband after demultiplexing, and to make a transparent structure consisting of a hierarchical structure in which an optical switch that performs switching in wavelength band units and an electrical switch that performs wavelength conversion are fused. An object of the present invention is to provide a duplexer suitable for use in an OXC device and an optical switching device using the duplexer.
[0020]
[Means for Solving the Problems]
Achieve the above objectives Therefore, in the present invention Such a duplexer, when demultiplexing a plurality of light wavelength-multiplexed within a predetermined wavelength band, Wavelength passband When The center wavelength of the wavelength passband Can be controlled independently Configured to .
[0023]
In the present invention, Refractive index modulation multilayer structure Refractive index control is performed by electricity, light and temperature. In the present invention, voltage application to the liquid crystal and voltage application to the material exhibiting the electro-optic effect are used as control by electricity.
[0026]
Furthermore, in another aspect of the present invention that achieves the above object, there is provided a demultiplexing module in which any of the demultiplexers and a plurality of demultiplexers are combined with an optical switch, and further using the demultiplexing module. An optical switching device is provided.
[0027]
In another aspect of the present invention that achieves the above object, an optical switching device using any one of the duplexers is provided.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0029]
[First embodiment]
An outline of the configuration and operation of the first embodiment of the present invention will be described. FIG. 1 is a perspective view for explaining the configuration of the duplexer according to the present embodiment. As shown in FIG. 1, the duplexer in the first embodiment of the present invention has a refractive index modulation multilayer structure, and has an optical filter unit 1001 having the refractive index modulation control mechanism, an actuator 1002, a light And a fiber 1003, which are mounted on a mounting package 1004.
[0030]
FIG. 2 is a perspective view for explaining the duplexer according to the first embodiment of the present invention. FIG. 3 is a plan view for explaining the configuration of the duplexer according to the first embodiment of the present invention. FIG. 4 is a diagram showing an upper surface (layout) of the wavelength filter unit of the duplexer according to the first embodiment of the present invention.
[0031]
As shown in FIGS. 2 and 3, the duplexer according to the present embodiment includes an optical filter unit 1, an actuator 2, and an optical fiber 3 mounted on a mounting package 4. The optical fiber 3 and the optical filter unit 1 are processed through an optical lens (not shown) or the like, or the tip of the optical fiber 3 is processed into a lens shape so that the light coupling efficiency is maximized during mounting. Are combined. Moreover, in order to suppress unnecessary resonance of light between the optical filter unit 1 and the optical fiber 3, an AR (antireflection) coat is applied to the end surfaces of the optical filter unit 1 and the optical fiber 3 as necessary.
[0032]
Further, as shown in FIG. 4, the optical filter unit 1 is opposed to apply a voltage to the movable mirror unit 11, the fixed mirror unit 12, and the liquid crystals 21 </ b> A to 21 </ b> D filled in the movable mirror unit 11. Transparent electrodes 13A and 13B to 16A and 16B to be arranged, and transparent electrodes 17A and 17B to transparent electrodes 20A and 20B arranged to face each other in order to apply a voltage to the liquid crystals 21F to 21H filled in the fixed mirror portion 12, respectively. It has.
[0033]
Refraction of the liquid crystal 21A to the liquid crystal 21H is applied to the liquid crystal 21A to the liquid crystal 21H filled in the movable mirror part 11 and the fixed mirror part 12 through the transparent electrodes 13A and 13B to the transparent electrodes 20A and 20B. The wavelength passband transmitted through the optical filter unit 1 is changed by changing the rate and changing the reflectivity of the movable mirror unit 11 and the fixed mirror unit 12 as a whole. As a result, the transmission output signal light λ emitted from the fixed mirror unit 12 among the wavelength-multiplexed incident signal beams λ1 to λn incident on the movable mirror unit 11. _i The passband can be changed.
[0034]
[Function of each component]
Next, the operation of each component of the duplexer according to the first embodiment of the present invention will be described in detail.
[0035]
First, the wavelength filter unit (optical filter unit 1 in FIG. 2) of the duplexer of the present invention will be described in detail.
[0036]
In the present embodiment, the optical filter section of the duplexer has a Fabry-Perot etalon structure well known as a wavelength filter. In the Fabry-Perot interference optical filter, only light having a wavelength matching the phase condition is resonantly transmitted through a gap (cavity) between two mirrors facing in parallel. The reflectivity of the two mirrors determines the wavelength passband of the transmitted light spectrum. The pair of mirrors constituting the resonator has a regular refractive index modulation periodic structure, and such a structure is called a “photonic crystal”.
[0037]
The behavior of light in the photonic crystal is explained using the concept of a photonic band corresponding to the energy band of electrons in a semiconductor. In a semiconductor, there is a frequency region in which electrons cannot have a specific mode due to the presence of a periodic potential, and in a photonic crystal, a frequency region in which light cannot have a specific mode. There is a photonic band gap. This photonic band gap generally opens over a wider band as the refractive index modulation of the refractive index periodic structure is stronger.
[0038]
In FIG. 4, the wavelength division multiplexed light λ is placed on the movable mirror 11. ₁ ~ Λ _n Is incident, the wavelength λ satisfying the expression (1) is satisfied in the wavelength band within the photonic band gap. _m Only the signal light is resonantly transmitted and emitted from the fixed mirror portion 12.
[0039]
λ _m = 2L / m (1)
[0040]
Here, L is the distance between the pair of mirrors (optical), that is, the cavity length, and m is an integer.
[0041]
A movable mirror portion 11 or a fixed mirror portion 12 made of a photonic crystal is shown in FIG. The movable mirror part 11 or the fixed mirror part 12 is made of a one-dimensional photonic crystal having a periodic structure of a structural material layer 30 in which rectangular holes are formed and a liquid crystal 31 filled in the holes. . Each layer thickness d _i Is the center wavelength of the filter operating band in vacuum, and the refractive index of each layer is n _i As shown in equation (2).
[0042]
d _i = Kλ / 4n _i ... (2)
[0043]
Here, λ is the center wavelength of the wavelength passband of the duplexer. k is an odd integer.
[0044]
In order for a mirror portion made of a one-dimensional photonic crystal to function as a mirror, k must be an odd number.
[0045]
The wavelength passband of the light emitted from the fixed mirror unit 12 (see FIG. 4) is determined by the reflectance of the movable mirror unit 11 and the fixed mirror unit 12 (see FIG. 4). Specifically, the wavelength passband is narrowed as the reflectivity of the mirror is increased, and the wavelength passband is expanded as the reflectivity of the mirror is decreased. The reflectivity of the mirror is such that the intensity of refractive index modulation between the structural material layer 30 (see FIG. 5) and the liquid crystal 31 filled in the holes (see FIG. 5), the number of repetitive periodic structures, and It is determined by the value of k in the above equation (2).
[0046]
The intensity of this refractive index modulation, the number of periodic structures, and the value of k are actually the variable bandwidth of the required wavelength passband, the restrictions on the process of making repeated periodic structures (process aspect ratio, etc.), etc. It is selected after considering various conditions.
[0047]
What is selected as the structural material layer 30 (see FIG. 5) constituting the mirror as described above is appropriately selected according to the use of the duplexer according to the present invention and the manufacturing process. That is, the photonic band gap of the movable mirror unit 11 and the fixed mirror unit 12 (see FIG. 4) needs to sufficiently cover the entire wavelength band (C band, L band, and S band) of optical communication. The intensity of refractive index modulation between the structural material layer 30 and the liquid crystal 31 (see FIG. 5) needs to be sufficiently large. In addition to this, it is necessary for the material to be capable of mirror production by the production process. That is, the optimal material may vary depending on the process employed. For example, in the case of a machining process by micromachining, Si having a sufficient record in the field of semiconductor microfabrication technology and having a high refractive index is suitable. Further, GaAs, InP, or the like can also be used as a material equivalent to Si. In addition, Si or the like is suitable for a manufacturing process by sputtering.
[0048]
Further, as a characteristic required for the liquid crystal 31 (see FIG. 5), the photonic band gap generated by the refractive index modulation with the structural material layer 30 can sufficiently cover the optical communication wavelength band, and It is necessary to have a refractive index anisotropy large enough to obtain a desired wavelength passband change amount. Specific examples include nematic liquid crystal, cholesteric liquid crystal, and ferroelectric liquid crystal. Nematic liquid crystal is desirable in the sense that the change in refractive index due to the change in orientation is large, but it is a matter of course that other liquid crystal materials can be appropriately selected depending on the required change in refractive index.
[0049]
Furthermore, as a material of the transparent electrodes 13A and 13B to the transparent electrodes 20A and 20B (see FIG. 4), indium oxide doped with tin oxide or a thin film of tin oxide can be used.
[0050]
Note that the above-described materials and characteristics described as being suitable for the structural material layer 30 and the liquid crystal 31 (see FIG. 4) are examples for realizing a wavelength filter having a desired function in the present invention. Of course, the present invention is not limited to such materials and properties. For example, if a process for accurately producing a material having a higher refractive index than Si is developed with a high aspect ratio, a structural material layer and a liquid crystal corresponding to the process can be appropriately selected.
[0051]
Further, in the present embodiment, since the refractive index of the liquid crystal in the mirror portion is changed by applying a voltage, the d value of the formula (2) (d in FIG. 5) is used depending on the refractive index value. _lc ) Will be different. Therefore, d at the time of design _lc The physical length is d in any case within the range of the refractive index of the liquid crystal to be variable. _lc The physical length.
[0052]
After designing in this way, if the refractive index of the liquid crystal is actually changed, d _lc Therefore, not only the wavelength passband but also the wavelength passband center wavelength λ changes. Therefore, the position of the wavelength passband center wavelength λ is maintained by changing the cavity length in a direction that cancels out the change in the wavelength passband center wavelength λ. This point will be described in detail in the description of the operation of the present embodiment described later.
[0053]
Next, the actuator unit (2 in FIGS. 2 and 3) of the duplexer in the present embodiment will be described.
[0054]
The characteristics required for the actuator section of the duplexer of the present embodiment include a desired wavelength passband center wavelength λ for optical communication applications. _i Any actuating mechanism that can cover the amount of change and that can ensure sufficient mirror parallel accuracy within the actuating range may be used. Specifically, an electrostatic drive actuator using electrostatic attraction and repulsion acting between electrodes, an electromagnetic drive actuator using a magnetic force acting between magnetic materials magnetized by the principle of electromagnetic induction, etc. Selected.
[0055]
Moreover, in this invention, as above-mentioned, it is not limited to the structure which changes the clearance gap between the movable mirror part 11 and the fixed mirror part 12 (refer FIG. 4) mechanically with an actuator. For example, the following (a) to (d) can also be appropriately selected.
[0056]
(a) The gap between the movable mirror portion 11 and the fixed mirror portion 12 can be filled with liquid crystal, and after filling the liquid crystal, a voltage is applied to the liquid crystal to change the effective optical path length between the gaps. Center wavelength λ of desired wavelength passband _i To change.
[0057]
(b) A material exhibiting an electro-optic effect (Pockels effect) that causes a change in refractive index when a voltage is applied between the movable mirror portion 11 and the fixed mirror portion 12, such as LiNbO. ₃ Using the crystal, change the effective optical path length between the gaps in the same way to change the center wavelength λ of the desired wavelength passband. _i To change.
[0058]
(c) Filling the gap between the movable mirror part 11 and the fixed mirror part 12 with a material that changes the refractive index by light irradiation, such as a spiro organic compound, and changing the effective optical path length between the gaps by light irradiation. Let the center wavelength λ of the desired wavelength passband _i To change.
[0059]
(d) The gap between the movable mirror portion 11 and the fixed mirror portion 12 is filled with a material that changes the refractive index due to a temperature change, such as silicon oil, and the effective optical path length between the gaps is changed by the temperature change. Center wavelength λ of the wavelength passband _i To change.
[0060]
[Description of manufacturing method]
Next, a specific example of the method of manufacturing the duplexer according to the present embodiment will be described. FIG. 6 is a diagram schematically showing a cross-sectional configuration of the duplexer according to the present embodiment.
[0061]
As shown in FIG. 6, first, a substrate 40 made of a transparent material such as glass is prepared in the wavelength band used (in this case, the wavelength band of optical communication), and Si41A and tin oxide are formed on the glass substrate 40. Transparent electrode 42A, SiO ₂ An oxide layer 43A and a transparent electrode 42B made of tin oxide are produced by sputtering. This manufacturing process is repeated for four cycles, and finally Si41E is formed. Si layer thickness d _s , SiO ₂ Layer thickness d _lc Was as follows.
[0062]
That is, the center wavelength λ (λ in the equation (2)) of the wavelength passband of the duplexer is set to a wavelength used for optical communication of 1.55 μm, the refractive index of Si is 3.5, and the refraction at the time of voltage application of liquid crystal described later is applied. From rate 1.1, assuming m = 1 in equation (2),
d _s = 0.111 μm
d _lc = 0.352 μm
It was.
[0063]
The layer thickness of the transparent electrodes 42A and 42B is preferably as thin as possible within a range where wire bonding for voltage application can be performed from the viewpoint of light loss. The film forming rate by sputtering and other film forming conditions greatly affect the smoothness of the film surface. In general, the mirror surface of a Fabry-Perot etalon type wavelength filter is required to have a flatness of about 1/100 of the wavelength. From this, in this Embodiment, film-forming was performed on the film-forming conditions which can achieve the smoothness of a 0.01-0.02 micrometer level.
[0064]
A groove was formed in the multilayer film 44 formed as described above as shown in FIG. Then, the multilayer film 44 in which the groove is formed is immersed in an HF aqueous solution, and an oxide film (SiO ₂ The film) was removed by etching. At this time, the etching is finished at the stage where the oxide film at the upper portion of the groove is removed, and care is taken so that the oxide film at portions other than the upper portion of the groove remains as a spacer.
[0065]
The multilayer film including the spacer was cut out as shown in FIG. 8, and the liquid crystal was filled into the space formed by the sacrifice layer etching by capillary force. Here, the liquid crystal having the molecular structure shown in FIG. 13, which is known as one of nematic liquid crystals, was used.
[0066]
The change in the refractive index of the liquid crystal due to the voltage is measured in advance by measuring the amount of movement of the diffraction peak of light by the liquid crystal filled in the same space as described above. As a result of the measurement, it was found here that the refractive index changed from 1.5 when no voltage was applied to 1.1 when the voltage was 60V.
[0067]
Two mirrors produced as described above are prepared and are designated as mirrors 46 and 47 in FIG.
[0068]
In this embodiment, one of the mirrors 46 and 47, the mirror 46 is mounted on the actuator 48 as shown in FIG. The actuator 48 employed in this embodiment is an electrostatic drive type and has a comb-tooth structure having two pairs of fixed electrodes and movable electrodes. The reason for using two pairs of electrodes is that the accuracy of actuation is higher and the mirror parallel accuracy is easier to ensure than in the case of one pair.
[0069]
Also, the other mirror, that is, in this embodiment, the mirror 47 is opposed to the mirror 46 in parallel, and the distance d _cav Fixed apart.
[0070]
d _cav Is twice the assumed wavelength λ = 1.55 μm, ie
d _cav = 3.10 μm
It was.
[0071]
The actuator 48 and the optical fiber on which the mirror 46 is mounted were mounted on a package 48-1 as shown in FIG. In the present embodiment, an optical fiber 49 having a fiber end surface processed into a lens shape is used, and AR coating is applied to the optical fiber end surface and the mirror end surface.
[0072]
[Description of operation]
Next, the operation of the duplexer of the present embodiment will be specifically described. FIG. 10 is a diagram for explaining the operation of the duplexer of the present embodiment, in which laser light is incident on the duplexer of FIG. 9 and spectrum analysis is performed on the output (transmitted light) of the spectrometer. is there. Referring to FIG. 10, the wavelength λ = 1 from the end face of the optical fiber 49 facing the movable mirror 46 (see FIG. 9) opposite to the end face facing the movable mirror 46 using the wavelength tunable laser 161. .45 μm to 1.62 μm of light was continuously incident, and the end surface of the optical fiber 49 facing the fixed mirror 47 opposite to the end surface facing the fixed mirror 47 was connected to the optical spectrum analyzer 162. Then, among the light having the wavelength λ = 1.45 μm to 1.62 μm swept by the wavelength tunable laser 161, the light component transmitted through the filter and its power were measured by the optical spectrum analyzer 162.
[0073]
First, without applying a voltage to the actuator 48 (see FIG. 9), the inter-mirror cavity length d _cav Was kept at 3.10 μm, and the transmitted light spectrum by the filter was measured in a state where 60 V was similarly applied to 8 pairs of transparent electrodes sandwiching 8 liquid crystal layers. The measurement result of the transmitted light spectrum is shown in FIG. As shown in FIG. 11A, the transmitted light spectrum was a transmitted light spectrum having a peak at the center wavelength λ = 1.55 μm as designed. At this time, the half width of the spectrum was about 0.1 nm.
[0074]
Next, the voltage applied to the eight pairs of transparent electrodes sandwiching the eight liquid crystal layers was removed, and the transmitted light spectrum by the filter was measured in that state. The results are shown in FIG. As shown in FIG. 11B, the center wavelength of the transmitted light spectrum was shifted to λ = 1.59 μm. This is because the mirrors 46 and 47 d _lc Since the length is designed based on the refractive index of the liquid crystal in a state where no voltage is applied to the liquid crystal, the optimum d is determined by the change in the refractive index when a voltage is applied to the liquid crystal. _lc This is because the length has changed. This shift in the center wavelength was compensated by changing the cavity length between the mirrors by applying a voltage to the actuator. That is, in this case, a voltage was applied between the fixed electrode and the movable electrode in the direction of narrowing the cavity length, and the center wavelength was moved to 1.55 μm as shown in FIG. At this time, the half width of the spectrum was about 0.28 nm.
[0075]
As described above, according to the duplexer of the first embodiment of the present invention, it is possible to change the half-value width of the transmitted light spectrum, that is, the wavelength passband while maintaining the center wavelength. In this embodiment, the passband in the case of the minimum value and the maximum value of the refractive index range of the liquid crystal is measured. By setting the voltage applied to the liquid crystal to an arbitrary value less than the maximum value, the refraction of the liquid crystal The rate can be arbitrarily changed. With this configuration, the wavelength passband can be arbitrarily set between about 0.1 nm and about 0.28 nm.
[0076]
Note that the liquid crystal is not limited to the liquid crystal having the above-described molecular structure, and other liquid crystal materials that generate a desired refractive index change upon application of a voltage can be appropriately selected.
[0077]
In the above embodiment, the operation is performed with the wavelength passband center wavelength λ = 1.55 μm. However, since the wavelength passband center wavelength λ can be shifted independently by the operation of the actuator, It is also possible to use as a duplexer that can change the wavelength passband at another center wavelength. However, in this case, as described in the description of the operation of the embodiment of the present invention, the half width of the spectrum is slightly larger than that in the case of using the design center wavelength (in this case, λ = 1.55 μm). In order to enlarge, the splitter is applied in consideration of this.
[0078]
As described above, the case where the wavelength filter is a bulk type has been described. However, the same effect as that of the above-described embodiment is that liquid crystal is filled in the refractive index modulation multilayer structure of the waveguide type wavelength filter in the same manner as described above. It can also be obtained by changing the refractive index of the liquid crystal.
[0079]
In the duplexer of the present embodiment, when the multiplexed light from which the wavelength light within the wavelength passband band of the filter is removed is input to the input port again, the multiplexed light is naturally totally reflected by the filter. At that time, if wavelength light in the wavelength passband band is input from the output port of the filter, the wavelength light in the wavelength passband input from the output port is superimposed on the reflected light from the filter. It can also be used as a multiplexer. This application is effective in an embodiment as an optical switching device described later.
[0080]
[Second Embodiment]
A second embodiment of the present invention will be described. [Summary of configuration and operation] and [Operation of each component] of the duplexer according to the second embodiment of the present invention are the same as those described in the first embodiment. Description is omitted.
[0081]
In this embodiment, instead of changing the reflectivity of the mirror by changing the refractive index of the liquid crystal in the first embodiment, the electro-optic effect in which the change of the refractive index is generated by applying a voltage is applied, as in the case of the liquid crystal. LiNbO which is a representative ferroelectric shown ₃ Crystals are used. LiNbO ₃ A manufacturing method and operation when a duplexer is configured using crystals will be described in detail.
[0082]
[Description of manufacturing method]
A method for manufacturing the duplexer according to the present embodiment will be described below. 12 and 13 are process cross-sectional views for explaining the manufacturing method of the present embodiment.
[0083]
First, LiNbO for changing the mirror reflectivity of the filter ₃ A method for manufacturing a waveguide will be described with reference to process cross-sectional views in FIGS. 12 (a) to 12 (g).
[0084]
First, LiNbO ₃ A waveguide pattern of a Ti film is formed on the substrate 110. The Ti film pattern is formed by coating the Ti film 111 by sputtering (see FIG. 12B), applying a photoresist 112 (see FIG. 12C), and forming a resist pattern by ordinary photolithography. The Ti film 111 was etched. That is, pattern exposure is performed through the mask 113 (see FIG. 12D), and then the photoresist is developed to remove the exposed portion (positive resist) (see FIG. 12E), and the photoresist 112 is masked. Then, the Ti film 111 as a base film is etched (see FIG. 12F), and the photoresist 112 is removed (see FIG. 12G). The thickness of the Ti film 111 was 20 nm. The waveguide length was 0.194 μm. The reason for this waveguide length will be described later.
[0085]
13 (a) to 13 (d) show LiNbO. ₃ It is a figure for demonstrating the process from spreading | diffusion of Ti in a board | substrate to electrode formation.
[0086]
LiNbO ₃ Diffusion of Ti into the substrate 110 (see FIG. 13A) was performed under the following conditions.
[0087]
Diffusion temperature: 1000 ° C
Diffusion time: 8h
Atmosphere: Air (air)
[0088]
The refractive index of the waveguide portion where the Ti was diffused was changed to rutile (TiO ₂ ) Measurement was performed using a prism (step of FIG. 13B). As a result, the refractive index of the waveguide portion was 2.0.
[0089]
Subsequently, TiN diffused LiNbO ₃ On the substrate 110, SiO ₂ A buffer film 114 was formed with a thickness of 100 nm by sputtering (see FIG. 13C).
[0090]
Furthermore, SiO ₂ An Al electrode film 115 having a thickness of 2 μm was formed on the buffer film 114 so as to straddle the Ti diffusion portion (see FIG. 13D). At that time, in order to increase the adhesion of the Al electrode film 115, a Cr base electrode was used.
[0091]
The above LiNbO incorporating a Ti diffusion waveguide ₃ The substrate 110 was diced, and a chip having the waveguide length was cut out. Ten chips were prepared.
[0092]
Next, a manufacturing process by micromachining of the filter part and the actuator part will be described.
[0093]
In the filter part and the actuator part in the present embodiment, the Si layer has a thickness of 4 μm, embedded SiO 2 ₂ Using an SOI (Silicon On Insulator) substrate with an oxide film thickness of 2 μm, the formation method is the same as the production method by micromachining described in the unpublished document (Reference 3) at the time of filing this application. It was done.
[0094]
[Reference 3]
Japanese Patent Application No. 2001-204213
[0095]
A perspective view of the optical filter unit 120 and the actuator unit 121 after the batch formation is shown in FIG. A top view of the mirror part of the optical filter part 120 is shown in FIG.
[0096]
Si layer thickness d of mirror part of optical filter part 120 _s , Gap length d formed by micromachining process _a , And set cavity length d _cav Was as follows.
[0097]
d _s = 0.111 μm
d _a = 0.194 μm
d _cav = 3.10 μm
[0098]
d _a The length is LiNbO to be mounted later. ₃ Since the refractive index of the waveguide was 2.0 as described above, it was determined by the equation (2) described in the first embodiment. Moreover, as shown in FIG. 15, the periodic structure of the mirror part of the optical filter part 120 formed five gaps by a micromachining process.
[0099]
Also in this embodiment, the actuator is an electrostatic drive type, and two pairs of electrodes are used, as in the case of the first embodiment, in order to ensure sufficient actuation accuracy.
[0100]
As described above, LiNbO in which a Ti diffusion waveguide is formed in the optical filter unit 120 formed together with the actuator unit 121. ₃ Ten chips were mounted. An enlarged top view of the filter unit 120 after mounting is shown in FIG.
[0101]
LiNbO ₃ The optical filter section 120 on which the chip is mounted and the actuator section 121 (integrated) are mounted in the same package as in FIG. 9 together with the same optical fiber as in FIG. Also in this embodiment, an optical fiber having a fiber end surface processed into a lens shape is employed, and AR coating is applied to the end surface of the optical fiber and the end surface of the mirror.
[0102]
[Description of operation]
Next, the operation of the duplexer of the present embodiment will be specifically described.
[0103]
As the optical characteristic evaluation system of the duplexer according to the embodiment of the present invention, the measurement system shown in FIG. 10 used in the description of the operation of the first embodiment is used as it is.
[0104]
First, the voltage between the actuator and the Al electrodes 132A and 132B to 141A and 141B (see FIG. 16) is not applied, and the inter-mirror cavity length d _cav Is kept at 3.10 μm and LiNbO ₃ With the refractive index of the waveguide portion being 2.0, the transmitted light spectrum by the filter was measured. The measurement results are shown in FIG. As shown in FIG. 17A, the transmitted light spectrum became a transmitted light spectrum having a peak at the center wavelength λ = 1.55 μm as designed. At this time, the half width of the spectrum was about 0.2 nm.
[0105]
Next, a voltage of 60 V was applied between the Al electrodes 132A and 132B to 141A and 141B, and the transmitted light spectrum with the filter was measured in that state. The results are shown in FIG. As shown in FIG. 17B, the center wavelength of the transmitted light spectrum was shifted to λ = 1.57 μm. The cause of this wavelength shift has been described in the description of the operation of the first embodiment. A voltage was applied in a direction to cancel out this wavelength shift, that is, in this case, a direction in which the cavity length was narrowed between the fixed electrode and the movable electrode of the actuator, and the center wavelength was moved to 1.55 μm. At this time, as shown in FIG. 17C, the half width of the spectrum was about 0.72 nm.
[0106]
The increase in the half-width of the transmitted light spectrum and the shift of the center wavelength are as follows. ₃ Since a voltage is applied to the waveguide portion, LiNbO is caused by the electro-optic effect (Pockels effect). ₃ This is because the refractive index of the waveguide portion has increased.
[0107]
As described above, according to the duplexer of the second embodiment of the present invention, it is possible to change the half-value width of the transmitted light spectrum, that is, the wavelength passband, while maintaining the center wavelength. Here, as in the duplexer of the first embodiment, the voltage applied between the Al electrodes is set to an arbitrary value by setting LiNbO. ₃ The refractive index of the waveguide portion can be arbitrarily changed in a scalable manner. As a result, the wavelength passband can be arbitrarily set between about 0.2 nm and about 0.72 nm.
[0108]
Note that the material used as the material exhibiting the electro-optic effect is the LiNbO used in this embodiment. ₃ The material is not limited to a crystal, and exhibits other electro-optic effect that causes a change in refractive index when a voltage is applied, such as LiTaO. ₃ Crystal, BaTiO ₃ A crystal and the like can be appropriately selected in consideration of a desired amount of change in refractive index. The material exhibiting the electro-optic effect is not limited to crystals, and may be amorphous or the like.
[0109]
In the case of the present embodiment, as in the case of the first embodiment, since the wavelength passband center wavelength λ can be shifted independently by the operation of the actuator, the design center wavelength (in this case) , Where λ = 1.55 μm), it is also possible to use as a demultiplexer that can change the wavelength passband at other center wavelengths, considering that the half width of the spectrum is slightly enlarged. .
[0110]
As described above, the case where the wavelength filter is based on the bulk type and the waveguide structure showing the electro-optic effect is mounted thereon has been described. However, the whole wavelength filter having the refractive index modulation multilayer structure is the waveguide type showing the electro-optic effect. The same effect can be obtained.
[0111]
In addition, when the demultiplexer according to the present embodiment inputs the multiplexed light from which the wavelength light in the wavelength passband band of the filter is removed to the input port, the multiplexed light is naturally totally reflected by the filter. At this time, if wavelength light in the wavelength passband band is input from the output port of the filter, the wavelength passband wavelength light input from the output port is superimposed on the reflected light from the filter. It can also be used as a container. This application is effective in an embodiment as an optical switching device described later.
[0112]
[Third embodiment]
The outline of the configuration and operation and the operation of each component of the duplexer of the present embodiment are all the same as those of the first and second embodiments. In the present embodiment, the change in the reflectivity of the mirror performed in the first and second embodiments is performed using an organic compound molecule aggregate that generates a change in refractive index due to light irradiation. The manufacturing method and operation of the duplexer of the present invention when the duplexer is configured will be described in detail.
[0113]
[Description of manufacturing method]
A method of manufacturing the duplexer according to the present embodiment will be described.
[0114]
The filter unit and the actuator unit of the duplexer of the present embodiment were manufactured by the manufacturing process by micromachining described in the description of the manufacturing method of the second embodiment.
[0115]
In this embodiment, the Si layer thickness d of the mirror portion of the filter corresponding to the optical filter portion 120 (see FIGS. 14 and 15) in the second embodiment. _s , Gap length d formed by micromachining process _a , And set cavity length d _cav Was as follows.
[0116]
d _s = 0.111 μm
d _a = 0.215 μm
d _cav = 3.10 μm
[0117]
d _a The length was described later in the first embodiment because the refractive index of the organic compound molecules (described later) filled in the gap when not irradiated with light was 1.8 as described later ( 2) Determined by the formula.
[0118]
Further, the number of gaps formed by the micromachining process in the mirror part of the filter part 120 is set to 4, which is one less than that in the case of the second embodiment (see FIG. 15).
[0119]
The actuator is manufactured by the same process as in the second embodiment, and is an electrostatic drive type of two pairs of electrodes.
[0120]
The organic compound that fills the gap in the mirror portion was a spiro compound 210 as shown in FIG. The compound molecular structure and photoreaction are shown in FIG.
[0121]
As shown in FIG. 18, the spiro compound spiropyran employed in this embodiment is isomerized into merocyanine by irradiation with ultraviolet light having a wavelength of 400 nm or less, and further heated to about 35 ° C. to form a J aggregate. To do. When the ultraviolet light is irradiated in an environment of about 35 ° C., it is possible to form a J aggregate from spiropyran. The J aggregate can be returned to spiropyran by heating to about 120 ° C.
[0122]
The change of the refractive index of the spiro compound shown in FIG. 18 due to irradiation with ultraviolet light is the amount of movement of the diffraction peak of the light due to the spiro compound filled in the same space (void) as the filter portion of the second embodiment. Was measured by measuring. As a result of the measurement, the refractive index when irradiated with the ultraviolet light for a sufficient time in an environment of a refractive index of 1.8 and about 35 ° C. before irradiation with ultraviolet light, that is, in a spiropyran state, is 2.2. Met. In addition, the spiro compound spiropyran employed in the present embodiment can be set to any refractive index between the two refractive indexes by controlling the irradiation time of ultraviolet light.
[0123]
Along with the actuator portion, a spiro compound was filled with a capillary force into a gap portion of the filter portion formed in a batch by a process by micromachining. An enlarged top view of the filter part after filling is shown in FIG. In FIG. 19, 223A to 223D and 223E to 223H are spiro compound spiropyrans filled in the gap between the movable mirror part 221 and the fixed mirror part 222 of the filter part.
[0124]
The filter unit filled with the spiro compound and the actuator unit (integrated) were mounted on the package 230 together with the optical fiber 231 as shown in FIG. FIG. 20 is a perspective view showing how the present embodiment is mounted.
[0125]
In addition, a Peltier element 233 was mounted in the package 230 for temperature measurement and temperature control of the filter unit. In addition, the optical fiber 231 employ | adopted the optical fiber which processed the fiber end surface into the lens form, and gave AR coating to the optical fiber end surface and the mirror end surface.
[0126]
[Description of operation]
Next, the operation of the duplexer of the present embodiment will be specifically described.
[0127]
As the optical characteristic evaluation system for the duplexer according to the embodiment of the present invention, the measurement system shown in FIG. 10 used in the description of the operation of the first and second embodiments was used as it was.
[0128]
First, without applying voltage to the actuator, the cavity length d _cav Was kept at 3.10 μm, and the transmitted light spectrum of the filter was measured in a state where the spiropyrans 223A to 223H were not irradiated with ultraviolet light for refractive index modulation. The results are shown in FIG. As shown in FIG. 21A, the transmitted light spectrum became a transmitted light spectrum having a peak at the center wavelength λ = 1.55 μm as designed. At this time, the half width of the spectrum was about 0.16 nm.
[0129]
Next, a current was passed through the Peltier element 233 to keep the temperature of the filter part at about 35 ° C., and the spiropyrans 223A to 223H were irradiated with ultraviolet light sufficient to form J aggregates from the spiroline. And the transmitted light spectrum by a filter was measured. The results are shown in FIG. As shown in FIG. 21B, the center wavelength of the transmitted light spectrum was shifted to λ = 1.57 μm. The cause of this wavelength shift has been described in the description of the operations of the first and second embodiments. A voltage was applied in a direction to cancel out this wavelength shift, that is, in this case, a direction in which the cavity length was narrowed between the fixed electrode and the movable electrode of the actuator, and the center wavelength was moved to 1.55 μm. At this time, the half width of the spectrum was about 1.52 nm.
[0130]
The increase in the half-width of the transmitted light spectrum and the shift of the center wavelength are caused by the fact that spiropyrans 223A to 223H are irradiated with ultraviolet light, so that J aggregates are formed from the spiroline, resulting in an increase in the refractive index of the spiro compound. This is because.
[0131]
Subsequently, after the voltage applied to the actuator is released and the cavity length is returned to the initial position, a current is passed through the Peltier element 233, and the filter is passed for a sufficient time to form a spiroline again from the J aggregate. The temperature of the part was kept at about 120 ° C. When the transmitted light spectrum by the filter was measured again, both the center wavelength position of the transmitted light spectrum and the half-value width of the spectrum reversibly returned to the initial state shown in FIG.
[0132]
As described above, according to the duplexer of the third embodiment of the present invention, it is possible to change the half-value width of the transmitted light spectrum, that is, the wavelength passband, while maintaining the center wavelength. Here, as in the case of the duplexers of the first and second embodiments, the refractive index of spiropyran can be arbitrarily changed in a scalable manner by controlling the time for irradiating the spiropyran with ultraviolet light. Is possible. As a result, the wavelength passband can be arbitrarily set between about 0.16 nm and about 1.52 nm.
[0133]
Note that the material that exhibits a change in refractive index when irradiated with light is not limited to the spiro compound used in this embodiment, and other materials that cause a change in refractive index when irradiated with light may have a desired refractive index. It can be selected as appropriate in consideration of the amount of change.
[0134]
In the case of the present embodiment as well, as in the case of the first and second embodiments, the wavelength passband center wavelength λ can be shifted independently by the operation of the actuator. In this case, it is also possible to use as a demultiplexer capable of changing the wavelength passband at other center wavelengths, considering that the half width of the spectrum is slightly enlarged as compared with the case of using at λ = 1.55 μm). Is possible.
[0135]
As described above, the case where the wavelength filter is a bulk type has been described. However, the same effect is obtained by filling the refractive index modulation multilayer structure of the waveguide type wavelength filter with a material that exhibits a refractive index change by light irradiation. It can also be obtained by changing the refractive index of the material. It can also be obtained by controlling the refractive index of the refractive index modulation multilayer structure of the fiber type wavelength filter with light.
[0136]
In addition, when the demultiplexer according to the present embodiment inputs the multiplexed light from which the wavelength light in the wavelength passband band of the filter is removed to the input port, the multiplexed light is naturally totally reflected by the filter. At this time, if wavelength light in the wavelength passband band is input from the output port of the filter, the wavelength passband wavelength light input from the output port is superimposed on the reflected light from the filter. It can also be used as a container. This application is effective in an embodiment as an optical switching device described later.
[0137]
[Fourth embodiment]
The outline of the configuration and operation of the duplexer of the present embodiment and the function of each component are all the same as those of the first to third embodiments. In this embodiment, the duplexer of the present invention is configured by using the organic compound in which the change in the refractive index is caused by the change in temperature due to the change in the reflectance of the mirror performed in the first to third embodiments. The manufacturing method and operation of the duplexer of the present invention will be described in detail.
[0138]
[Description of manufacturing method]
A method of manufacturing the duplexer according to the present embodiment will be described.
[0139]
The filter unit and the actuator unit of the duplexer of the present embodiment were manufactured by the manufacturing process by micromachining described in the description of the manufacturing method of the second and third embodiments.
[0140]
In this embodiment, the Si layer thickness d of the mirror part of the filter corresponding to the filter part 120 in the second embodiment. _s , Gap length d formed by micromachining process _a , And set cavity length d _cav Was as follows.
[0141]
d _s = 0.111 μm
d _a = 0.291 μm
d _cav = 3.10 μm
[0142]
d _a Since the length of the silicon oil, which is an organic compound molecule filling the void, changes monotonically from a refractive index of 1.33 at about 20 ° C. to a refractive index of 1.5 at about 70 ° C., the length is about 20 ° C. The refractive index value of 1.33 was determined by the equation (2) described in the first embodiment. The number of voids formed by the micromachining process in the mirror part of the optical filter part was 4.
[0143]
Further, since the actuator is manufactured by the same process as that of the second embodiment, it is also an electrostatic drive type of two pairs of electrodes here.
[0144]
Along with the actuator portion, silicon oil was filled into the gap portion of the filter formed by a process by micromachining by capillary force. The enlarged top view of the filter part after filling is in the form in which the position of the spiropyran in FIG. 19 is filled with silicon oil.
[0145]
The filter part filled with silicon oil and the actuator part (integrated) were mounted in the same package as that of FIG.
[0146]
[Description of operation]
Next, the operation of the duplexer of the present embodiment will be specifically described.
[0147]
As the optical characteristic evaluation system for the duplexer according to the embodiment of the present invention, the measurement system shown in FIG. 10 used in the description of the operation of the first to third embodiments is used as it is.
[0148]
First, without applying a voltage to the actuator, the cavity length d _cav Was kept at 3.10 μm, and the transmitted light spectrum was measured while maintaining the temperature of the filter part at about 20 ° C. by a Peltier element (233 in FIG. 20). The measurement results are shown in FIG.
[0149]
As shown in FIG. 22A, the transmitted light spectrum became a transmitted light spectrum having a peak at the center wavelength λ = 1.55 μm as designed. At this time, the half width of the spectrum was about 0.02 nm.
[0150]
Next, a current was passed through the Peltier element (see 233 in FIG. 20) to keep the temperature of the filter section at about 70 ° C., and in this state, the transmitted light spectrum was measured. The measurement results are shown in FIG. As shown in FIG. 22B, the center wavelength of the transmitted light spectrum was λ = 1.55 μm, which was the same as when the temperature was about 20 ° C. At this time, the half width of the spectrum was about 0.04 nm.
[0151]
The increase in the half-value width of the transmitted light spectrum here is because the refractive index of silicon oil has increased due to an increase in temperature.
[0152]
Subsequently, the current flowing through the Peltier element was reduced, the temperature of the filter unit was returned to about 20 ° C., and the transmitted light spectrum by the filter was measured again. The half-value width of the transmitted light spectrum was as shown in FIG. ) Reversibly returned to the initial state of 0.02 nm.
[0153]
As described above, according to the duplexer of the fourth embodiment of the present invention, it is possible to change the half width of the transmitted light spectrum, that is, the wavelength passband, while maintaining the center wavelength. Also in this embodiment, the refractive index of silicon oil can be arbitrarily changed in a scalable manner by controlling the temperature of the silicon oil, as in the case of the duplexers of the first to third embodiments. Is possible. As a result, the wavelength passband can be arbitrarily set between about 0.02 nm and about 1.04 nm.
[0154]
Note that the material exhibiting a refractive index change due to a temperature change is not limited to the silicon oil used in this embodiment, and other materials that cause a refractive index change due to a temperature change are mainly polymer materials. Can be selected as appropriate.
[0155]
In the case of the present embodiment as well, as in the case of the first to third embodiments, the wavelength passband center wavelength λ can be shifted independently by the operation of the actuator. In the case of λ = 1.55 μm), it is possible to use as a demultiplexer that can change the wavelength passband at other center wavelengths, considering that the half width of the spectrum is slightly enlarged. It is.
[0156]
The case where the wavelength filter is a bulk type has been described above, but the same effect is obtained by filling a material that exhibits a refractive index change due to a temperature change, similar to the refractive index modulation multilayer structure of the waveguide type wavelength filter. It can also be obtained by changing the refractive index. It can also be obtained by controlling the refractive index of the refractive index modulation multilayer structure of the fiber type wavelength filter by temperature.
[0157]
Further, in the duplexer of the present embodiment, when the multiplexed light from which the wavelength light within the wavelength passband band of the filter is removed is input again to the input port, the multiplexed light is naturally totally reflected by the filter. In this case, if wavelength light in the wavelength passband band is input from the output port of the filter, the wavelength passband wavelength light input from the output port is superimposed on the reflected light from the filter. It can also be used as a waver. This application is effective in an embodiment as an optical switching device described later.
[0158]
[Fifth embodiment]
FIG. 23 is a diagram showing a cross section of the basic configuration of the fifth embodiment of the duplexer of the present invention using an FBG (fiber Bragg grating) structure.
[0159]
An optical fiber 503 having a Ge-added core was irradiated with ultraviolet rays to produce a refractive index distribution grating 504.
[0160]
Next, the temperature variable mechanism 505 was disposed around the refractive index distribution grating 504. Another temperature variable mechanism 506 is disposed around the gradient index grating 504. As the temperature variable mechanisms 505 and 506, ceramic heating elements were used. By passing an electric current through the ceramic heating element, heat can be generated and the temperature of the fiber Bragg grating can be controlled.
[0161]
In the duplexer of the present invention using the FBG structure, since there are a plurality of temperature variable mechanisms, a plurality of temperature regions can be provided in the gradient index grating, and the temperature difference between the plurality of temperature regions can be controlled. it can. As a result, the bandwidth of the selected waveform as shown in FIG. 24B can be controlled.
[0162]
In addition, the average value of a plurality of temperature settings can be controlled, whereby the center wavelength of the selected waveform as shown in FIG. 24A can be controlled.
[0163]
For example, when the wavelength multiplexed optical signal 500 of λ (1) to λ (i) to λ (j) to λ (n) is incident on the fiber Bragg grating 503, the temperature difference between the temperature variable mechanisms 505 and 506 is zero. When λ (i) is controlled to reflect the wavelength, the reflected wave 501 is λ (i), and the transmitted wave 502 is λ (1) to λ (i−1), λ (i + 1) to λ (n )
[0164]
When the temperature difference between the temperature variable mechanism 505 and the temperature variable mechanism 506 is generated and the reflected wave 501 is controlled to be λ (i−1) to λ (i + 1), the transmitted wave 502 is λ (1 ) To λ (i−2) and λ (i + 2) to λ (n).
[0165]
Further, when the average temperature is controlled and the center wavelength is changed to λ (j) while maintaining the temperature difference between the temperature variable mechanism 505 and the temperature variable mechanism 506, the reflected wave 501 is λ (j−1) to λ. (J + 1), and the transmitted wave 502λ becomes (1) to λ (j−2) and λ (j + 2) to λ (n).
[0166]
As described above, the bandwidth and center wavelength of the selected wavelength band can be tuned.
[0167]
As described above, the reflected light is selected light, and as a filter for controlling the bandwidth and center wavelength of the selected wavelength band, a similar refractive index modulation multilayer structure is provided in the bulk structure or waveguide structure, and the refractive index is Similar effects can be obtained by controlling the temperature as in the present embodiment.
[0168]
[Sixth embodiment]
FIG. 25 is a diagram showing a cross section of the basic configuration of the sixth embodiment of the duplexer of the present invention, which is different from the fifth embodiment using the FBG (fiber Bragg grating) structure.
[0169]
An optical fiber 603 having a Ge-added core was irradiated with ultraviolet rays to produce a refractive index distribution grating 604. Next, the stress variable mechanism 605 was disposed around the gradient index grating. Further, another variable stress mechanism 609 and a variable stress mechanism 612 are arranged around the gradient index grating 604. As the variable stress mechanism, lead zirconate titanate ceramics was used, and the adhesive was used for pasting. The variable stress mechanisms 605, 609, and 612 are provided with electrodes 606 and 607, electrodes 608 and 610, and electrodes 611 and 613, respectively, and by applying a voltage to these electrodes, lead zirconate titanate. Ceramics can be expanded and contracted.
[0170]
In the duplexer of the present invention using the FBG structure, since there are a plurality of variable stress mechanisms, a plurality of stress regions can be provided in the gradient index grating, and the stress difference between the plurality of stress regions can be controlled. . As a result, the bandwidth of the selected waveform as shown in FIG. 24B can be controlled.
[0171]
In addition, the average value of a plurality of stress settings can be controlled, whereby the center wavelength of the selected waveform as shown in FIG. 24A can be controlled.
[0172]
For example, when the wavelength multiplexed optical signal 600 of λ (1) to λ (i) to λ (j) to λ (k) to λ (n) is incident on the fiber Bragg grating 603, the variable stress mechanisms 605, 609, and 612 are used. When the stress difference of λ (i) is controlled to a wavelength reflected by λ (i), the reflected wave 601 becomes λ (i) and the transmitted wave 602 becomes λ (1) to λ (i−1) and λ (i + 1). ) To λ (n).
[0173]
In addition, when a stress difference between the stress variable mechanisms 605, 609, and 612 is generated and the reflected wave 601 is controlled to be λ (i−1) to λ (i + 1), the transmitted wave 602 is λ (1) to λ (i−2) and λ (i + 2) to λ (n).
[0174]
Further, when the average stress is controlled and the center wavelength is changed to λ (j) while maintaining the stress difference between the stress variable mechanisms 605, 609, and 612, the reflected wave 601 is λ (j−1) to λ ( j + 1), and the transmitted wave 602λ is (1) to λ (j−2) and λ (j + 2) to λ (n).
[0175]
As described above, the bandwidth and center wavelength of the selected wavelength band can be tuned.
[0176]
As described above, the same refractive index modulation multilayer structure is provided in the bulk structure or the waveguide structure as a filter for controlling the bandwidth and the center wavelength of the selected wavelength band using the reflected light as the selective light, and the refractive index is set as the main filter. Similar effects can be obtained by controlling the mirror shape change due to stress as in the embodiment.
[0177]
[Seventh embodiment]
FIG. 26 and FIG. 27 are diagrams schematically showing a cross section of the basic configuration of the seventh embodiment of the duplexer of the present invention. As shown in FIG. 26, the duplexer of the present embodiment has a Fabry-Perot etalon structure, and the filter portion is formed by micromachining similar to the manufacturing method of the second to fourth embodiments. Made in the process. That is, the semi-transmissive mirror portion 701 is made of Si, and the gap portion of the low refractive index layer is made of Air (air).
[0178]
In this embodiment, a mechanism 702 for moving a part 700 of the semi-transmissive mirror unit is provided. This moving mechanism 702 used an electrostatic actuator. Thereby, the substantial thickness of the semi-transmissive mirror part can be changed.
[0179]
In addition, a cavity gap interval adjusting mechanism 703 is provided on one side of the semi-transmissive mirror unit 701.
[0180]
A piezo element was used for the cavity gap adjusting mechanism 703. By controlling the voltage applied to the piezo element, the interval of the cavity gap 705 can be adjusted.
[0181]
For example, as shown in FIG. 26, when a wavelength multiplexed optical signal 706 of λ (1) to λ (i) to λ (n) is incident on the semi-transmissive mirror unit 701, the high refractive index layer (Si) and the low refractive index. When passing through the laminated structure of the layer (Air) and adjusting the cavity gap length corresponding to λ (i), the transmitted light 708 becomes λ (i), and the reflected light 707 has λ (1) ˜ λ (i−1) and λ (i + 1) to λ (n).
[0182]
Further, as shown in FIG. 27, when a part of the semi-transmissive mirror portion is moved, the film thickness of the semi-transmissive mirror portion is reduced as compared with the state of FIG. The rate drops. Since there is a relationship that the bandwidth increases when the reflectance decreases, the transmitted light 708 becomes λ (i−1) to λ (i + 1). The reflected light 707 at this time is λ (1) to λ (i−2) and λ (i + 2) to λ (n).
[0183]
On the other hand, by adjusting the cavity gap length by the cavity gap interval adjusting mechanism 703, the center wavelength of the transmitted wave can be controlled independently of the bandwidth.
[0184]
As described above, the bandwidth and center wavelength of the selected wavelength band can be tuned.
[0185]
[Eighth embodiment]
FIG. 28 is a diagram showing the configuration of the eighth embodiment of the present invention. As shown in FIG. 28, the duplexer according to the eighth embodiment is a duplexer module 807 including duplexers 801 to 805 and optical switches 806 that are designed to have different center wavelengths. The demultiplexers 801 to 805 are demultiplexers having variable wavelength path bandwidths, and any of the demultiplexers according to the first to seventh embodiments of the present invention may be used. The wavelength λ of the input wavelength multiplexed light to the demultiplexing module is λ ₁ = 1500 nm to λ ₁₆ A case will be described below as an example where light multiplexed by 17 wavelengths at intervals of 1 nm is demultiplexed to 1517 nm.
[0186]
The center wavelength of the demultiplexers 801 to 805 and the variable wavelength pass bandwidth were set as shown in FIG. By setting in this way, the duplexers 801 to 805 can each cover the wavelength passband shown in FIG. 30 at the maximum. For this reason, for example, by changing the wavelength passband of the demultiplexers 801 and 802, λ ₂ ~ Λ ₄ These three wavelengths can be output from either of the demultiplexers 801 and 802. The input wavelength multiplexed light is input to an arbitrary duplexer by the optical switch 807. The optical switch 807 may have any mechanism that can convert input wavelength multiplexed light into any one of the demultiplexers 801 to 805.
[0187]
With this configuration, the demultiplexing module 807 as a whole arbitrarily selects the number of wavelengths output via the demultiplexers 801 to 805 within the range of the wavelength passband variable region of the demultiplexers 801 to 805. It is possible. From this, the demultiplexing module 807 is a demultiplexer that can flexibly select a selected wavelength passband when demultiplexing a plurality of wavelengths that are wavelength-multiplexed within a predetermined wavelength band.
[0188]
Furthermore, taking advantage of the fact that the wavelength passband bandwidth and the wavelength passband center wavelength of the duplexer can be controlled independently, for example, as shown in FIG. ₁ ~ Λ ₄ Λ with a duplexer 802 ₅ Λ with a duplexer 803 ₆ ~ Λ ₁₁ And λ with demultiplexer 804 ₁₂ ~ Λ ₁₅ And λ with demultiplexer 805 ₁₆ , Λ ₁₇ For example, it is possible to provide a demultiplexing module capable of a more flexible selection wavelength configuration.
[0189]
When the demultiplexing module of this embodiment is applied to a transparent OXC apparatus, the wavelength passband variable region of the demultiplexer is considered in consideration of the total wavelength band to be covered and the wavelength channel interval required by the transparent OXC apparatus, In addition, by designing the variable band of the center wavelength of the wavelength passband, it is possible to provide a transparent OXC node device capable of flexible and efficient network operation using the configuration of the demultiplexing module of the present embodiment. is there.
[0190]
[Ninth embodiment]
FIG. 32 is a diagram showing the configuration of the ninth exemplary embodiment of the present invention. As shown in FIG. 32, an optical switching device 900 is configured using a demultiplexing module based on the same principle as described in the eighth embodiment. The wavelength-multiplexed light input to the optical switching device is light multiplexed by 101 waves from a wavelength of 1500 nm to a wavelength of 1600 nm with a wavelength interval of 1 nm. The demultiplexing module 901 is composed of ten demultiplexers and one optical switch, and all the ten demultiplexers include a wavelength passband variable band 1 nm to 10 nm and a wavelength passband center wavelength variable band 1500 nm to 1600 nm. did. The wavelength band switch 902 is a 12 × 12 matrix switch. Further, a demultiplexing module having the same specifications as the demultiplexing module 901 is connected to the output port of the wavelength band switch 902 as a multiplexing module 903 as shown in FIG.
[0191]
Further, as shown in FIG. 32, two of the 10 input ports and output ports of the wavelength band switch 902 are connected to the wavelength layer. The wavelength layer includes a wavelength switch (electric switch 904) and a plurality of optical / electrical converters, and an electrical / optical converter, two duplexers, and two multiplexers. A client device 905 is connected to the wavelength switch (electric switch 904).
[0192]
By using the optical switching device configured as described above, the wavelength passband variable band 1 nm to 10 nm of the duplexer 901 and the wavelength passband center wavelength variable band 1500 nm to 1600 nm, the wavelength transmitted to the wavelength layer, and The wavelength to be transmitted to the multiplexer 903 is an arbitrary number of 101 waves of light multiplexed in a wavelength band of 1500 nm to 1600 nm in the wavelength passband range of 1 nm to 10 nm, that is, in the range of 1 wave to 10 waves. The wavelength can be selected at an arbitrary wavelength passband center wavelength within a wavelength band of 1500 nm to 1600 nm.
[0193]
As described above, according to the optical switching device 900 of the present embodiment, when a wavelength within a limited wavelength band is divided into a plurality of wavelength passbands, the bands and wavelength passband center wavelengths that the plurality of passbands bear Can be set arbitrarily in a scalable manner, so that a limited wavelength band can be changed flexibly according to demand on the wavelength layer side, and it can be made an optical switching device capable of flexible and efficient network operation. is there.
[0194]
[Tenth embodiment]
As shown in FIG. 33, an optical switching device 950 is configured using a duplexer 951, a circulator 952, and a coupler 953 based on the same principle as described in any of the first to seventh embodiments. The wavelength multiplexed light input to the optical switching device 950 is 101 light multiplexed from a wavelength of 1500 nm to a wavelength of 1600 nm with a wavelength interval of 1 nm. The wavelength passband variable band of the demultiplexer 951 is 1 nm to 10 nm, and the wavelength passband center wavelength variable band is 1500 nm to 1600 nm.
[0195]
Since the demultiplexer 951 has a wavelength passband variable band of 1 nm to 10 nm and a wavelength passband center wavelength variable band of 1500 nm to 1600 nm, the wavelength selected by the demultiplexer 951 is 101 waves multiplexed in the wavelength band of 1500 nm to 1600 nm. Any number of wavelengths can be selected from the light in the wavelength passband range of 1 nm to 10 nm, that is, in the range of 1 wave to 10 waves, with any wavelength passband center wavelength within the wavelength band 1500 nm to 1600 nm. . Now select the wavelength λ _i , Λ _{i + 1} 2 wavelengths (λ ₁ (= 1500nm) ≦ λ _i , Λ _{i + 1} ≦ λ ₁₀₁ (= 1600 nm)).
[0196]
Residual light λ other than the selected light reflected by the duplexer 951 ₁ ~ Λ _i-1 , Λ _{i + 2} ≦ λ ₁₀₁ Is routed by the circulator and output in the direction of the coupler 953. In addition, the selected wavelength is λ _i , Λ _{i + 1} Are output from the drop port of the optical switching device 950 to the client device side.
[0197]
Wavelength λ output from the client device _i , Λ _{i + 1} 2 wavelengths (which are often different from the above information, but are not necessarily different information) are reflected to the demultiplexer 951 through the add port of the optical switching device 950 and the coupler 953. Light λ ₁ ~ Λ _i-1 , Λ _{i + 2} ≦ λ ₁₀₁ And output from the optical switching device 950. More preferably, a demultiplexer 954 having the same specifications as the demultiplexer 951 is provided as close as possible to the coupler 953 between the client device and the coupler 953, and does not become an obstacle when multiplexing via the coupler 953. Wavelength to about λ _i , Λ _{i + 1} The light λ reflected by the duplexer 951 after forming the two-wavelength spectrum shape of ₁ ~ Λ _i-1 , Λ _{i + 2} ≦ λ ₁₀₁ And multiplexed.
[0198]
With the optical switching configuration as described above, according to the optical switching device 950 of the present embodiment, the wavelength passband to be dropped and the wavelength passband center wavelength can be arbitrarily set in a scalable manner. It is possible to provide an optical switching device capable of flexible and efficient network operation, in which the wavelength band thus obtained can be changed in response to the demand on the client device side connected to the drop port. Although the present invention has been described with reference to the above embodiment, the present invention is not limited to the configuration of the above embodiment, and those skilled in the art within the scope of the invention of the appended claims. It goes without saying that various modifications and corrections that can be achieved are included.
[0199]
【The invention's effect】
As described above, according to the present invention, medium refractive index control of a duplexer having a refractive index modulation multilayer structure using transmitted light or reflected light as a selection wavelength can be applied to a liquid crystal or a material exhibiting an electro-optic effect. By performing voltage application, light, temperature, mirror shape change, and change in the number of layers of the refractive index modulation multilayer structure, the bandwidth of the selected wavelength can be made variable. In addition, since a mechanism for controlling the center wavelength of the selected wavelength is provided independently of the mechanism, a duplexer capable of independently controlling the bandwidth of the selected wavelength and the center wavelength of the selected wavelength bandwidth can be obtained.
[0200]
Further, according to the optical switching device using the duplexer according to the present invention, it is possible to arbitrarily control the wavelength passband and the wavelength passband center wavelength of the duplexer, the passband setting according to demand, It is possible to provide an optical switching device capable of setting the passband center wavelength.
[Brief description of the drawings]
FIG. 1 is a perspective view for explaining a configuration of a duplexer according to an embodiment of the present invention.
FIG. 2 is a perspective view for explaining the configuration of the duplexer according to the first embodiment of the present invention.
FIG. 3 is a top view of the duplexer according to the first embodiment of the present invention.
FIG. 4 is a diagram schematically showing a configuration of a wavelength filter unit of the duplexer according to the first embodiment of the present invention.
FIG. 5 is a diagram schematically showing a configuration of a wavelength filter unit of the duplexer according to the first embodiment of the present invention.
FIG. 6 is a diagram schematically showing a configuration of a wavelength filter unit of the duplexer according to the first embodiment of the present invention.
FIG. 7 is a diagram illustrating an example of a liquid crystal molecular structure.
FIG. 8 is a diagram schematically showing a configuration of a wavelength filter unit of the duplexer according to the first embodiment of the present invention.
FIG. 9 is a perspective view showing a configuration when the duplexer according to the first embodiment of the present invention is mounted.
FIG. 10 is a diagram for explaining optical characteristic evaluation of the duplexer according to the first embodiment of the present invention.
FIGS. 11A to 11C are diagrams showing optical spectra obtained by the duplexer according to the first embodiment of the present invention. FIGS.
12A to 12G are process cross-sectional views illustrating a manufacturing process of a duplexer according to a second embodiment of the present invention.
FIGS. 13A to 13D are process cross-sectional views illustrating a manufacturing process of a duplexer according to a second embodiment of the present invention. FIGS.
FIG. 14 is an exploded view schematically showing a configuration of a wavelength filter unit of a duplexer according to a second embodiment of the present invention.
FIG. 15 is a diagram schematically illustrating a configuration of a wavelength filter unit of a duplexer according to a second embodiment of the present invention.
FIG. 16 is a diagram schematically illustrating a configuration of a wavelength filter unit of a duplexer according to a second embodiment of the present invention.
FIGS. 17A to 17C are diagrams showing optical spectra obtained by the duplexer according to the second embodiment of the present invention. FIGS.
FIG. 18 is a diagram for explaining a molecular structure of a spiro compound employed in a duplexer according to a third embodiment of the present invention and a change in molecular structure due to light and temperature.
FIG. 19 is a diagram schematically illustrating a configuration of a wavelength filter unit of a duplexer according to a third embodiment of the present invention.
FIG. 20 is a perspective view showing a configuration of a duplexer according to a third embodiment of the present invention.
FIGS. 21A to 21C are diagrams showing optical spectra obtained by the duplexer according to the third embodiment of the present invention. FIGS.
FIGS. 22A to 22C are diagrams showing optical spectra obtained by the duplexer according to the fourth embodiment of the present invention. FIGS.
FIG. 23 is a diagram for explaining a schematic cross-sectional configuration of a wavelength filter of a duplexer according to a fifth embodiment of the invention.
FIG. 24A is a diagram showing transmission waveforms before and after the center wavelength shift by the duplexers of the fifth and sixth embodiments of the present invention, and FIG. It is a figure which shows the transmission waveform before and behind the wavelength passband change by the branching filter by embodiment.
FIG. 25 is a diagram showing a schematic cross section of a wavelength filter of a duplexer according to a sixth embodiment of the present invention.
FIG. 26 is a diagram schematically showing a state before moving a wavelength filter movable transflective mirror of a duplexer according to a seventh embodiment of the present invention;
FIG. 27 is a diagram schematically illustrating a state after the wavelength filter movable transflective mirror of the duplexer according to the seventh embodiment of the present invention is moved.
FIG. 28 is a diagram showing a configuration of a demultiplexing module according to an eighth embodiment of the present invention.
FIG. 29 is a diagram showing a center wavelength and a wavelength pass bandwidth of each duplexer constituting the demultiplexing module according to the eighth embodiment of the present invention.
FIG. 30 is a diagram showing the center wavelength and the maximum wavelength pass bandwidth of each duplexer constituting the demultiplexing module according to the eighth embodiment of the present invention.
FIG. 31 is a diagram showing a center wavelength and a wavelength pass bandwidth of each duplexer constituting the demultiplexing module according to the eighth embodiment of the present invention.
FIG. 32 is a diagram schematically showing a configuration of an optical switching device according to a ninth embodiment of the present invention.
FIG. 33 is a diagram schematically showing a configuration of an optical switching device according to a tenth embodiment of the present invention.
FIG. 34 is a diagram showing a configuration of a transparent OXC apparatus.
FIG. 35 is a diagram for explaining a conventional duplexer.
FIG. 36 is a diagram for explaining a conventional duplexer.
FIG. 37 is a diagram for explaining a conventional duplexer.
FIG. 38 is a diagram for explaining a conventional duplexer.
FIG. 39 is a diagram for explaining a demultiplexing method that cannot be realized by a conventional demultiplexer.
[Explanation of symbols]
1 Optical filter section
2 Actuator
3 Optical fiber
4 Mounting package
11 Movable mirror part
12 Fixed mirror
13A, 13B, 14A, 14B, 15A, 15B, 16A, 16B, 17A, 17B, 18A, 18B, 19A, 19B, 20A, 20B Transparent electrode
21A, 21B, 21C, 21D, 21E, 21F, 21G, 21H
30 Structural material layer
31 liquid crystal
40 Transparent substrate
41A Si
42A, 42B Transparent electrode
43A SiO ₂ Oxide layer
41E Si
46, 47 Mirror
48 Actuator
48-1 Mounting Package
49 Optical fiber
101 Transparent OXC (Optical Cross Connect) equipment
102 Wavelength band switch
103 Wavelength switch
104 duplexer
110 LiNbO ₃ substrate
111 Ti film
112 resist
113 Mask
114 SiO ₂ Buffer membrane
115 Al electrode
120 Optical filter section
121 Actuator
130 Movable mirror part
131 Fixed mirror
132A, 132B, 133A, 133B, 134A, 134B, 135A, 135B, 136A, 136B, 137A, 137B, 138A, 138B, 139A, 139B, 140A, 140B, 141A, 141B Al electrodes
161 Tunable laser
162 Optical spectrum analyzer
221 Movable mirror part
222 Fixed mirror
223A, 223B, 223C, 223D, 223E, 223F, 223G, 223H Spiropyran
230 Mounting package
231 Optical fiber
232 Filters and actuators (batch formation)
233 Peltier element
500 wavelength multiplexed input light
501 Reflected light
502 Transmitted light
503 Optical fiber (Ge-doped core)
504 Refractive index distribution grating
505 Variable temperature mechanism
506 Variable temperature mechanism
510 Transmission waveform (before center wavelength shift)
511 Transmission waveform (after center wavelength shift)
512 Transmission waveform (before wavelength passband change)
513 Transmission waveform (after wavelength passband change)
600 wavelength multiplexed light
601 Reflected light
602 Transmitted light
603 Optical fiber (Ge-doped core)
604 Refractive index distribution grating
605, 609, 612 Stress variable mechanism
606, 607, 608, 610, 611, 613 electrode
700 Movable transflective mirror
701 transflective mirror
702 Movable transflective mirror moving mechanism
703 Cavity gap interval adjustment mechanism
705 cavity gap
706 Wavelength multiplexed input light
707 Reflected light
708 Transmitted light
801, 802, 803, 804, 805 duplexer
806 Optical switch
807 demultiplexing module
810 Maximum wavelength pass bandwidth of duplexer 801
811 Demultiplexer 801 wavelength passband center wavelength
812 Demultiplexer 802 maximum wavelength pass bandwidth
813 Wavelength passband center wavelength of demultiplexer 802
814 Maximum wavelength pass bandwidth of duplexer 803
815 Wavelength of passband center wavelength of demultiplexer 803
Maximum wavelength pass bandwidth of 816 demultiplexer 804
817 Wavelength passband center wavelength of demultiplexer 804
818 Maximum wavelength pass bandwidth of duplexer 805
819 Demultiplexer 805 wavelength passband center wavelength
Wavelength pass bandwidth of 820 demultiplexer 801
821 Wavelength of passband center wavelength of demultiplexer 801
822 Wavelength pass bandwidth of duplexer 802
823 wavelength passband center wavelength of demultiplexer 802
Wavelength pass bandwidth of 824 demultiplexer 803
825 wavelength passband center wavelength of demultiplexer 803
826 Wavelength pass bandwidth of duplexer 804
827 Wavelength passband center wavelength of demultiplexer 804
Wavelength pass bandwidth of 828 duplexer 805
829 Demultiplexer 805 wavelength passband center wavelength
901 demultiplexing module
902 Wavelength band switch
903 multiplexing module
904 Wavelength switch
905 client device
951 duplexer
952 Circulator
953 Coupler
954 duplexer
1001 Optical filter unit (including refractive index modulation control mechanism)
1002 Actuator
1003 Optical fiber
1004 Mounting package

Claims (12)

A wavelength filter unit that inputs and demultiplexes and outputs a wavelength-multiplexed optical signal,
A first mirror part and a second mirror part arranged on the optical path;
Variable means for varying the gap length between the first mirror part and the second mirror part,
The first mirror unit and the second mirror unit each include a refractive index modulation multilayer structure including a plurality of film structures in which a refractive index is variably controlled.
The refractive index change in the refractive index modulation multilayer structure changes the reflectance of the entire first mirror part and the second mirror part, thereby changing the wavelength passband transmitted through the wavelength filter, and Of the wavelength-multiplexed incident signal light incident on one mirror part, the passband of the transmitted output signal light emitted from the second mirror part is changed,
By varying the gap length between the mirrors of the first mirror part and the second mirror part, the center wavelength of the wavelength passband is independent of the change of the wavelength passband by the refractive index modulation multilayer structure, A duplexer characterized by being freely shiftable . The first mirror part and the second mirror part are opposed to each other with the liquid crystal filled in the holes provided in the structural material of each mirror part sandwiching the liquid crystal as the refractive index modulation multilayer structure. 2. The duplexer according to claim 1, wherein a plurality of transparent electrode pairs are provided, and a voltage applied to the counter electrode is varied to vary a refractive index of the liquid crystal . The first mirror portion and the second mirror portion are respectively formed on a waveguide formed by diffusing metal on the surface of a ferroelectric substrate exhibiting an electro-optic effect, and on both substrates with the waveguide interposed therebetween. 2. A ferroelectric light guide waveguide comprising a plurality of ferroelectric light guide waveguides each including an electrode provided on the electrode, and the refractive index of the waveguide portion is varied by varying a voltage applied to the electrode. The duplexer described in 1. In each of the first mirror part and the second mirror part, as the refractive index modulation multilayer structure, organic compound molecule aggregates in which the refractive index changes due to light irradiation are formed in the vacancies of the mirror structural material. The duplexer according to claim 1, wherein the duplexer has a configuration of being filled . In each of the first mirror part and the second mirror part, as the refractive index modulation multilayer structure, vacancies in the structural material of the mirror are filled with organic compound molecules whose refractive index changes due to temperature change. And has a configuration
The duplexer according to claim 1, further comprising means for variably controlling the temperature of the refractive index modulation multilayer structure . The gap between the first mirror part and the second mirror part is filled with liquid crystal, and the variable means changes the effective optical path length between the gaps by applying a voltage to the liquid crystal. 6. The duplexer according to claim 1, wherein a center wavelength of the wavelength passband is changed . In the gap between the first mirror portion and the second mirror portion, a material exhibiting an electro-optic effect that causes a change in bending rate by application of a voltage is disposed, and the variable means has the electro-optic effect. 6. The voltage according to any one of claims 1 to 5, wherein the effective optical path length between the gaps is changed to change the center wavelength of the wavelength passband by applying a voltage to the indicated material. Duplexer. The gap between the first mirror part and the second mirror part is filled with a material that causes a refractive index change by light irradiation, and the variable means irradiates the material with light, 6. The duplexer according to claim 1, wherein an effective optical path length between the gaps is changed to change a center wavelength of the wavelength passband . The gap between the first mirror part and the second mirror part is filled with a material that causes a change in refractive index due to a temperature change, and the variable means changes the temperature of the material by changing the temperature of the material. 6. The duplexer according to claim 1, wherein an effective optical path length between the gaps is changed to change a center wavelength of the wavelength passband .   A demultiplexing module comprising the plurality of demultiplexers according to claim 1 and an optical switch. An optical switching device using the duplexer according to claim 1. An optical switching device using the branch module according to claim 10.

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