JP2005157069A - Dispersion compensation module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dispersion compensation module capable of realizing dispersion compensation and waveform shaping in optical fiber transmission with a simple constitution. <P>SOLUTION: This dispersion compensation module is equipped with: at least one optical transmission line 111 having a core where a chirp grating 112 is formed; and an expanding and contracting means of controlling the distribution of strain of the chirp grating in a light propagation direction. This expanding means is equipped with: a plurality of expanding and contracting members 114 to 118 which are arrayed in the light propagation direction; and a support member 113 which is thermally connected to each of the plurality of expanding and contracting members 114 to 118. The optical transmission line 111 is fixed to the support member 113 through the plurality of expanding and contracting members 114 to 118, and the support member 113 and the plurality of expanding and contracting members 114 to 118 transmit heat to each other to control the temperatures of the expanding and contracting members 114 to 118. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a dispersion compensation module for compensating for chromatic dispersion of an optical signal generated in optical fiber communication or the like.

  With recent advances in optical networks, the importance of dispersion compensation technology in optical fiber transmission lines is increasing. In the case where 1.5 μm band light with low transmission loss is transmitted using the existing 1.3 μm band optical fiber transmission line, chromatic dispersion of about 17 ps / km · nm occurs. For this reason, when the transmission rate of the optical signal becomes high or the transmission distance becomes long, the optical signal is significantly deteriorated due to the chromatic dispersion. Therefore, it is necessary to appropriately compensate the chromatic dispersion.

  Conventionally, there is a dispersion compensation module as a typical device for compensating for such chromatic dispersion. The dispersion compensation module uses a dispersion compensation fiber having a dispersion characteristic opposite to that of a normal optical fiber that transmits an optical signal, thereby changing the waveform of the optical signal due to chromatic dispersion in the optical fiber transmission line. To compensate for dispersion. Such a dispersion compensation module has a disadvantage that the device cannot be miniaturized because a dispersion compensating fiber is required to be several km or more.

  As another type of dispersion compensation module, an apparatus using a fiber grating in which a grating (diffraction grating) is formed in the core of an optical fiber is known. Such a type of dispersion compensation module uses a chirped Bragg grating whose grating period changes along the axial direction of the optical fiber.

The fiber grating is manufactured using interference exposure with ArF second-order harmonics or KrF ultraviolet laser light in a continuous refractive index modulation period in the core of the optical fiber, or using a phase mask. The Bragg wavelength λ _B is expressed as λ _B = 2 × neff × Λ using the grating period Λ and the effective refractive index neff of the grating. A grating whose diffraction grating period changes in the longitudinal direction is called a chirped fiber grating. Since the grating period Λ continuously changes, the Bragg reflection wavelength λ _B also changes continuously. For this reason, since the delay time varies depending on the distance to the reflection point of the light corresponding to each reflection wavelength λ _B in the fiber grating, chromatic dispersion can be provided.

  A chromatic dispersion compensation module can be realized by utilizing the properties of the chirped fiber grating. FIG. 6 shows a configuration of a dispersion compensation module including such a grating fiber. Hereinafter, the configuration and operation of the dispersion compensation module of FIG. 6 will be described.

  The dispersion compensation module shown in FIG. 6 includes an optical circulator 613 having an input terminal 614a, an input / output terminal 614b, and an output terminal 614c, and a fiber grating 615 coupled to the input / output terminal 614b of the optical circulator 613.

  The input terminal 614a and the output terminal 614c of the optical circulator 613 are respectively coupled to a transmission optical fiber (not shown). It is assumed that the waveform of the optical signal transmitted through the transmission optical fiber changes under the influence of chromatic dispersion existing in the transmission optical fiber.

  The core 616 of the fiber grating 615 is formed with a chirped Bragg grating in which the grating period (grating interval) changes continuously and monotonously.

  When the input light 611 is input to the input terminal 614a of the optical circulator 613, the input light 611 reaches the fiber grating 615 via the input / output terminal 614b. The core 616 of the fiber grating 615 reflects the input light 611 toward the input / output terminal 614b of the optical circulator 613 by Bragg reflection. The reflection position of the input light 611 in the fiber grating 615 differs depending on the wavelength because the grating period has a distribution in the axial direction. That is, the axial distribution of the grating period is set so as to restore the waveform change of the input light 611 caused by chromatic dispersion in the transmission optical fiber. More specifically, the chromatic dispersion received by the fiber grating 615 after being input to and reflected by the fiber grating 615 is adjusted so that the chromatic dispersion in the signal transmission optical fiber has the same absolute value and the opposite polarity. Has been. As a result, when the light reflected by the fiber grating 615 and returned from the input / output terminal 614b to the optical circulator 613 is output as the output light 612 from the output terminal 614c, the chromatic dispersion is compensated.

  The chromatic dispersion of the fiber grating 615 shown in FIG. 6 has a preset and fixed value. For this reason, the wavelength band and compensation amount cannot be changed dynamically (adaptively). In order to appropriately compensate the influence of chromatic dispersion that the input light 611 receives on the transmission optical fiber, it is preferable that the reflection band and dispersion can be changed by dynamically changing the grating period. A dispersion compensation module having such a function is disclosed in Patent Document 1 and the like. In the dispersion compensation module disclosed in Patent Document 1, a temperature change is applied to the composite member by a heater or the like, thereby causing bending deformation of the composite member due to heat. As a result, the fiber grating is distorted, and the reflection wavelength and reflection band of the grating can be dynamically changed.

Next, a conventional dispersion compensation module described in Patent Document 1 will be described with reference to FIG. The dispersion compensation module shown in FIG. 7 includes a composite member (bimetal) 15 in which two types of members 13 and 14 having different thermal expansion coefficients are bonded, an optical fiber 18 in which a chirped grating 11 is formed, and a composite member 15. And a transmission member 12 that exerts bending deformation on the optical fiber 18 due to temperature change. A heater 17 is formed on the surface of the composite member 15. When Joule heat is generated in the heater 17 by energizing the heater 17, the temperature of the composite member 15 can be changed by this heat generation. Since the two types of members 13 and 14 constituting the composite member 15 have different thermal expansion coefficients, the bending deformation increases or decreases depending on the temperature change. By this bending deformation, strain is applied in the major axis direction of the optical fiber 18. Due to this distortion, the chirp rate of the chirped grating 11 is changed, so that chromatic dispersion can be controlled.
JP 2002-72034 A

  When performing optical time division multiplexing (OTDM) transmission with a transmission rate exceeding 100 Gbps, not only chromatic dispersion of the optical fiber but also higher-order dispersion such as dispersion slope (third-order dispersion) is compensated. There is a need to. However, in the dispersion compensation module shown in FIG. 7, since the chirped grating 11 is expanded and contracted by the bending of the composite member 15, the amount of change in the chirp rate is substantially uniform along the major axis direction of the chirped grating 11. For this reason, according to such a dispersion compensation module, high-order dispersion such as dispersion slope cannot be sufficiently compensated.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to variably perform control of chromatic dispersion necessary for dispersion compensation and waveform shaping in optical fiber transmission with a simpler configuration than before. It is to provide a dispersion compensation module capable of

  The dispersion compensation module is a dispersion compensation module comprising at least one optical transmission line having a core on which a chirped grating is formed, and expansion / contraction means for controlling the distribution of distortion in the light propagation direction of the chirped grating, The expansion / contraction means includes a plurality of expansion / contraction members arranged along the light propagation direction and a support member thermally connected to each of the plurality of expansion / contraction members, and the optical transmission path includes the plurality of expansion / contraction members. The elastic member is fixed to the support member via an elastic member, and the temperature of the elastic member is controlled by transferring heat between the support member and the plurality of elastic members.

  In a preferred embodiment, each of the plurality of elastic members forms a strain in the major axis direction of the chirped grating according to its own temperature change.

  In a preferred embodiment, at least one of the plurality of elastic members is formed of a material having a thermal expansion coefficient different from that of the other elastic members.

  In a preferred embodiment, the plurality of elastic members are connected to each other by a fixing member.

  In a preferred embodiment, the fixing member has a thermal conductivity and a thermal expansion coefficient smaller than the thermal expansion coefficient and the thermal expansion coefficient, respectively.

  In a preferred embodiment, the optical transmission line is a fiber grating.

  In a preferred embodiment, the fixing member has a through hole through which the fiber grating passes.

  In a preferred embodiment, at least a part of the support member is formed of a material that generates heat and / or absorbs heat.

  In a preferred embodiment, the material is a Peltier element or a heater.

  In a preferred embodiment, the apparatus further includes a temperature control unit that controls heat generation and heat absorption by the material and / or the heat absorbing material.

  In a preferred embodiment, the optical system includes an optical signal analysis unit that calculates a dispersion amount to be compensated based on an analysis result of the optical signal output from the dispersion compensation module, and the temperature based on the calculation result of the optical signal analysis unit. Controls the operation of the controller.

  ADVANTAGE OF THE INVENTION According to this invention, the dispersion compensation module which controls the reflective wavelength by a chirped fiber grating by a thermal strain, and compensates a wavelength dispersion can be provided.

(Embodiment 1)
First, the configuration of a first embodiment of a dispersion compensation module according to the present invention will be described with reference to FIGS. FIG. 1A is a longitudinal sectional view schematically showing a configuration of a main part of the dispersion compensation module according to this embodiment, and FIG. 1B is a transverse sectional view taken along the line BB.

  The dispersion compensation module of this embodiment includes at least one optical transmission line (optical fiber) 111 having a core on which a Bragg grating (hereinafter referred to as “chirp grating”) 112 having a chirp structure is formed, and a chirp grating 112. Expansion and contraction means for controlling the distribution of strain in the light propagation direction. The chirped grating 112 is manufactured by periodically changing the refractive index of the core portion in the optical fiber 111 along the axial direction by a known method. On the other hand, the expansion / contraction means includes a plurality of expansion / contraction members 114 to 118 arranged along the light propagation direction, and a support member 113 thermally connected to each of the expansion / contraction members 114 to 118.

  As shown in FIG. 1, the optical fiber 111 is fixed to the support member 113 via a plurality of elastic members 114 to 118. More specifically, a portion of the optical fiber 111 where the chirped grating 112 is formed is fixed to the elastic members 114 to 118. As will be described later, according to the dispersion compensation module of the present embodiment, heat is transmitted between the support member 113 and the elastic members 114 to 118, and the temperature changes. Due to this temperature change, each of the elastic members 114 to 118 thermally expands or contracts, and expands and contracts in the long axis direction of the optical fiber 111. A characteristic point of this embodiment is that the thermal expansion coefficient of each of the elastic members 114 to 118 is designed to change along the long axis direction of the optical fiber 111.

  At least a part of the support member 113 that supports the elastic members 114 to 118 is made of a heat absorbing / releasing material such as a Peltier element or a heater, and the temperature of the elastic members 114 to 118 can be raised or lowered. The stretchable members 114 to 118 are preferably formed from a material that easily causes thermal expansion and contraction.

  In the present embodiment, the temperature of the support member 113 and the elastic members 114 to 118 can be increased or decreased by applying a current or voltage to the support member 113. As a result, axial strain can be applied to a desired region of the optical fiber 111, thereby changing the grating period in that region. The magnitude of such axial strain depends on the thermal expansion coefficient of the elastic members 114 to 118. For this reason, necessary expansion and contraction can be realized by appropriately selecting the material of the expansion and contraction members 114 to 118.

  The temperature change of the elastic members 114 to 118 is controlled by the current or voltage applied to the support member 113. This control is performed by the temperature control device 122.

  As shown in FIGS. 1A and 1B, each of the elastic members 114 to 118 is provided with a through-hole 119 having a shape and a size through which the optical fiber 111 can pass. A cylindrical fixing member 120 is partially inserted into the through-hole 119, and the elastic members 114 to 118 are connected to each other by the fixing member 120. When the outer diameter Φ1 of the optical fiber 112 is, for example, 0.125 mm, the inner diameter Φ2 of the through hole 119 is set to about 5 mm. The size of the telescopic members 114 to 118 in the optical fiber major axis direction is set to about 8 to 20 mm, for example. The size of the fixing member 120 in the optical fiber major axis direction is set to about 5 to 15 mm, for example.

  The size of the elastic members 114 to 118 in the direction perpendicular to the major axis direction of the optical fiber 111 is set to, for example, 25 mm in the horizontal horizontal direction and 25 mm in the vertical horizontal direction, as shown in FIG. . Further, as shown in FIG. 1B, the size of the support member 113 in the direction perpendicular to the major axis direction is set to 30 mm in the horizontal lateral direction and 5 mm in the vertical lateral direction, for example.

  The fixing member 120 is preferably formed of a material having a smaller thermal conductivity and thermal expansion coefficient than the material of the elastic members 114 to 118. Thereby, it is possible to suppress the influence by the heat conduction from the expansion-contraction members 114-118 or thermal expansion to the minimum. An optical fiber 111 is inserted into the through hole 119 and the fixing member 120, and the fixing member 120 is connected to the optical fiber 111. In addition, a material having a lower thermal conductivity than the elastic members 114 to 118 is enclosed in the gap between the elastic members 114 to 118 and the optical fiber 111, and unnecessary temperature changes in the optical fiber 111 are suppressed. Specifically, quartz glass having a thermal conductivity of about 1.35 can be used. The thermal conductivity of such a material is much smaller than that of metals such as copper and iron.

  One end of the optical fiber 111 is coupled to the optical circulator 124, and the waveform of light reflected by the grating 112 of the optical fiber 111 is analyzed by the optical signal analyzer 123.

  Hereinafter, the operation of the dispersion compensation module of this embodiment will be described.

  First, the temperature of the support member 113 is detected by the temperature detector 121 and controlled within a desired temperature range by the temperature adjustment device 122.

  Next, the optical signal output from the dispersion compensation module of this embodiment is input to the optical signal analyzer 123. The optical signal analyzer 123 is preferably an autocorrelator, a spectrum analyzer, or a network analyzer. The optical signal analyzer 123 analyzes the input optical signal and calculates the amount of dispersion to be compensated.

  Next, the temperature adjusting device 122 described above controls the temperature of the support member 113 based on the amount of dispersion to be compensated. Since the support member 113 and the expansion / contraction members 114 to 118 are in thermal contact, the temperature of the expansion / contraction members 114 to 118 also changes based on the temperature change of the support member 113, causing thermal expansion and contraction.

  When the elastic members 114 to 118 are heated and extended, it is not preferable that the optical fiber 111 is heated. This is because the effective refractive index of the chirped grating 112 varies with temperature changes. In order to prevent such fluctuations, it is preferable to suppress heat transfer from the elastic members 114 to 118 to the optical fiber 111 as much as possible with the above-described configuration.

  Since each elastic member 114-118 is mutually connected by the fixing member 120, the optical fiber 111 can be stably attached with respect to each elastic member 114-118.

  After the fixing member is attached to the optical fiber, the fixing member is fixed to the elastic member. In order to fix the fixing member to the optical fiber, an adhesive may be used, or the optical fiber may be mounted in a groove provided at the center of the fixing member. As a method of connecting the expansion / contraction member to the fixing member, (1) after attaching the fixing member to the concave / convex groove provided in the expansion / contraction member, the upper portion of the expansion / contraction member is extended from the through-hole to the lower portion of the expansion / contraction member. (2) After attaching the fixing member to the uneven groove provided in the expansion / contraction member, the upper portion of the expansion / contraction member is connected to the lower portion of the fixing member from the through-hole 119. There is a method in which a magnet is provided on the outer periphery of the fixing member provided in the elastic member adhesion portion, and the elastic member is fixed by a magnetic force.

  Since the fixing member 120 is formed of a material (for example, quartz glass) having a lower thermal conductivity and a lower thermal expansion coefficient than the elastic members 114 to 118, the period of the chirp grating 112 is increased by the heat from the elastic members 114 to 118. Can be prevented from changing.

  As described above, according to the dispersion compensation module of the present embodiment, the period of the chirped grating 112 can be dynamically changed. A specific example of performing dispersion compensation of ultrashort pulse light using this dispersion compensation module will be described.

  Since the ultrashort pulse light has a wide frequency spectrum component, when the ultrashort pulse light is transmitted through the optical fiber, it is inevitably affected by chromatic dispersion. The pulse width of the ultrashort pulse light affected by the chromatic dispersion becomes wider than before input.

    According to the dispersion compensation module of this embodiment, the residual dispersion value in a desired wavelength band can be reduced by changing the temperature of the support member 113. By setting the support member 113 to a heated or endothermic state, the temperature and the expansion coefficient of each of the elastic members 114 to 118 are adjusted, thereby imparting a desired strain gradient to the chirped grating 112.

Assume that the elastic members 114 to 118 in the present embodiment are made of iron, nickel, constantan, copper, and manganin, respectively. Moreover, the axial direction length of each expansion-contraction member 114-118 is set to 10 mm. In this case, the thermal expansion coefficient α1 of iron is 11.8 × 10 ⁻⁶ (° C. ⁻¹ ), the thermal expansion coefficient α2 of nickel is 13.4 × 10 ⁻⁶ (° C. ⁻¹ ), and the thermal expansion coefficient α3 of constantan is ^{15.0 × 10 -6 (℃ -1)} , the thermal expansion coefficient α4 of copper ^{16.5 × 10 -6 (℃ -1)} , the thermal expansion coefficient α5 of manganin is 18.1 × 10 ^-6 (℃ ^{- 1} ), when the temperature of the support member 113 is increased by 10 ° C., the expansion amounts of the elastic members 114 to 118 are 0.118 μm, 0.134 μm, 0.150 μm, 0.165 μm, and 0.185 μm, respectively. Become. As described above, in the present embodiment, a strain that linearly changes in size along the long axis direction is applied to the optical fiber 111.

  Here, it is assumed that the dispersion compensation module of the present embodiment can compensate for a dispersion amount of −150 ps / nm in a wavelength band within the range of 1550 nm to 1552 nm before the distortion is applied. In this case, when the linear distortion gradient is given to the chirped grating 112 by extending the elastic members 114 to 118 in the axial direction as described above, the period at each part of the chirped grating 112 changes due to the linear distortion. To do. With such a change in period, the relative group delay changes as shown in FIG. 3 in the wavelength band of 1550 nm to 1552 nm. Since the chromatic dispersion is the first derivative of the relative group delay, the amount of dispersion that can be compensated can be variably controlled to -100 ps / nm.

(Embodiment 2)
Next, a second embodiment of the dispersion compensation module according to the present invention will be described with reference to FIG. The main difference is the difference in the configuration of the elastic members. Except for this point, the dispersion compensation module of this embodiment has the same configuration as that of the dispersion compensation module in the first embodiment. Therefore, in the following description, characteristic points of the dispersion compensation module of the present embodiment will be described.

  Each of the dispersion compensation modules shown in FIG. 2 includes elastic members 214 to 218 made of silicon, brass, aluminum, brass, and silicon. The lengths of the elastic members 214 to 218 in the present embodiment in the axial direction are all 10 mm.

The thermal expansion coefficient α6 of silicon is 2.6 × 10 ⁻⁶ (° C. ⁻¹ ), the thermal expansion coefficient α7 of brass is 17.5 × 10 ⁻⁶ (° C. ⁻¹ ), and the thermal expansion coefficient α8 of aluminum is 23.1. Since it is × 10 ⁻⁶ (° C. ⁻¹ ), when each temperature of the elastic member is increased by 10 ° C. with the support member 113, the expansion amounts of the elastic members 214 to 218 are 0.26 μm, 1.75 μm, 2.31 μm, 1.75 μm, and 0.26 μm. For this reason, distortion that changes in a quadratic function along the axial direction is given to the grating 112.

  As described above, according to the present embodiment, it is possible to impart a distortion whose gradient changes in a quadratic function to the bug rating 112 and thereby control the dispersion slope.

  In the case where the above-described distortion is not applied, it is assumed that the dispersion amount of 175 ps / nm can be compensated in the wavelength band of 1550 nm to 1552 nm. When a strain gradient is applied to the chirped grating 112 as a quadratic function, the period of each part of the grating changes due to this strain, so that the Bragg reflection wavelength of light can be controlled. When the above-mentioned distortion that changes in a quadratic function is applied to the grating 112, the relative group delay changes as shown in the figure.

  As shown in FIG. 5, the chromatic dispersion before applying strain is constant at 175 ps / nm with respect to the wavelength. However, by applying the strain gradient, the chromatic dispersion is in the wavelength band from 1550 nm to 1552 nm. It varies linearly from 150 ps / nm to 200 ps / nm.

First derivative i.e. the dispersion curve, since the second derivative of the group delay curve represents the dispersion slope, it is possible to change the dispersion slope before and after temperature application from 0 ps / nm ² to 25 ps / nm ^2.

  As described above, in each embodiment of the present invention, the axial distribution of strain is linearly changed simply by changing the temperature of a single support member by appropriately arranging elastic members formed from different materials. It is possible to change in a functional or quadratic function. If the relationship between the amount of strain due to heat of each expansion member and the amount of change in temperature is known in advance, the optimum amount of strain can be calculated simply by detecting the temperature of the support member or expansion member.

  The amount of dispersion to be compensated by the dispersion compensation module can be obtained by analyzing an optical signal output from the dispersion compensation module by a known optical signal analyzer. By associating the amount of dispersion to be compensated with the amount of temperature change, the degree of dispersion compensation can be adaptively changed with respect to environmental changes due to temperature fluctuations or the like of the entire transmission line.

  As described above, according to each embodiment of the present invention, a dispersion compensation module that performs dispersion compensation and waveform shaping in optical fiber transmission is realized with a simpler configuration than in the past.

  Parameters such as the number of fiber gratings, the number of elastic members, the shape and size of the elastic members, and the shape of the fiber grating are set appropriately according to the bandwidth and the amount of dispersion of the optical fiber to be compensated. obtain.

  The present invention provides a dispersion compensation module that compensates for dispersion by controlling the reflection wavelength of a Bragg grating by thermal strain caused by a metal or alloy that is at least one strain gradient applying means in contact with the longitudinal direction of the fiber grating and the grating. can do.

(A) is the longitudinal cross-sectional view of 1st Embodiment of the dispersion compensation module by this invention, (b) is the BB line cross-sectional view. It is sectional drawing of 2nd Embodiment of the dispersion compensation module by this invention. It is a graph which shows the wavelength-group delay characteristic in the 1st Embodiment of this invention. It is a graph which shows the wavelength-group delay characteristic in the 2nd Embodiment of this invention. The figure which shows the wavelength-dispersion characteristic in the 2nd Embodiment of this invention. It is a figure explaining the dispersion compensation method by fiber grating. It is a figure which shows the conventional dispersion compensation module.

Explanation of symbols

111 Optical Fiber 112 Chirp Bragg Grating 113 Support Member 114 Elastic Member (Iron)
115 Elastic member (nickel)
116 Elastic member (constantan)
117 Elastic member (copper)
118 Elastic member (manganin)
119 Through-hole 120 Fixing member 121 Temperature detector 122 Temperature control device 123 Optical signal analysis device 124 Optical circulator 214 Elastic member (silicon)
215 Elastic member (brass)
216 Elastic member (aluminum)
217 Elastic member (brass)
218 Elastic member (silicon)
611 Input light 612 Output light 613 Optical circulator 614 Optical circulator terminal 615 Chirp Bragg grating 616 Core

Claims (11)

At least one optical transmission line having a core on which a chirped grating is formed;
Expansion and contraction means for controlling the strain distribution in the light propagation direction of the chirped grating,
A dispersion compensation module comprising:
The expansion / contraction means is
A plurality of elastic members arranged along the light propagation direction;
A support member thermally connected to each of the plurality of elastic members;
With
The optical transmission path is fixed to the support member via the plurality of elastic members,
A dispersion compensation module that controls the temperature of the elastic member by transferring heat between the support member and the plurality of elastic members. 2. The dispersion compensation module according to claim 1, wherein each of the plurality of elastic members forms a strain in a major axis direction of the chirped grating in accordance with a temperature change of itself. The dispersion compensation module according to claim 1, wherein at least one of the plurality of elastic members is formed of a material having a thermal expansion coefficient different from that of the other elastic members. The dispersion compensation module according to claim 1, wherein the plurality of elastic members are connected to each other by a fixing member. The dispersion compensation module according to claim 4, wherein a thermal conductivity and a thermal expansion coefficient of the fixing member are smaller than the thermal conductivity and the thermal expansion coefficient of the elastic member, respectively.   The dispersion compensation module according to claim 5, wherein the optical transmission line is a fiber grating. The dispersion compensation module according to claim 6, wherein the fixing member has a through hole through which the fiber grating passes. The dispersion compensation module according to claim 1, wherein at least a part of the support member is formed of a material that generates heat and / or absorbs heat. The dispersion compensation module according to claim 8, wherein the material is a Peltier element or a heater. The dispersion compensation module according to claim 8, further comprising a temperature control unit that controls heat generation and heat absorption by the material. Based on the analysis result of the optical signal output from the dispersion compensation module, comprising optical signal analysis means for calculating the amount of dispersion to be compensated,
The dispersion compensation module according to claim 10, wherein an operation of the temperature control unit is controlled based on a calculation result of the optical signal analysis unit.

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