WO2001084750A1 - Dispositif de compensation de dispersion optique et procede de compensation de dispersion optique utilisant ledit dispositif - Google Patents

Dispositif de compensation de dispersion optique et procede de compensation de dispersion optique utilisant ledit dispositif Download PDF

Info

Publication number
WO2001084750A1
WO2001084750A1 PCT/JP2001/003769 JP0103769W WO0184750A1 WO 2001084750 A1 WO2001084750 A1 WO 2001084750A1 JP 0103769 W JP0103769 W JP 0103769W WO 0184750 A1 WO0184750 A1 WO 0184750A1
Authority
WO
WIPO (PCT)
Prior art keywords
optical
dispersion compensation
dispersion
layer
multilayer film
Prior art date
Application number
PCT/JP2001/003769
Other languages
English (en)
Japanese (ja)
Inventor
Kazuro Kikuchi
Yuichi Takushima
Mark Kenneth Jablonski
Yuichi Tanaka
Haruki Kataoka
Kenji Furuki
Noboru Higashi
Kazunari Sato
Shiro Yamashita
Original Assignee
Oyokoden Lab Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Oyokoden Lab Co., Ltd. filed Critical Oyokoden Lab Co., Ltd.
Priority to AU2001252667A priority Critical patent/AU2001252667A1/en
Publication of WO2001084750A1 publication Critical patent/WO2001084750A1/fr

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
    • G02B6/29392—Controlling dispersion
    • G02B6/29394—Compensating wavelength dispersion
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2507—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion
    • H04B10/2513—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion
    • H04B10/25133—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion due to chromatic dispersion including a lumped electrical or optical dispersion compensator

Definitions

  • dispersion means chromatic dispersion
  • optical dispersion compensation is also simply referred to as dispersion compensation
  • optical dispersion compensating element is simply referred to as dispersion compensating element. This is also simply referred to as a dispersion compensation method.
  • the present invention relates to an element capable of compensating for a second- or higher-order (hereinafter described) dispersion occurring in optical communication using an optical fiber as a transmission line (hereinafter, an element capable of changing the second-order dispersion, or a second-order dispersion).
  • an element capable of compensating for the third-order dispersion described later includes an element capable of changing the third-order dispersion or a third-order dispersion compensating element.
  • the present invention relates to a dispersion compensating element and a dispersion compensating method using the element.
  • the present invention particularly relates to a dispersion compensating element capable of compensating for a tertiary or higher order dispersion, or a dispersion compensating element capable of performing a secondary and tertiary or higher order dispersion compensation, and an element thereof. And a dispersion compensation method using the same.
  • the dispersion compensating element used in the dispersion compensating method of the present invention may be only the tertiary dispersion compensating element described above, or may include a unit for changing the incident position of incident light in the incident plane described later.
  • dispersion compensating element of the present invention includes all of these forms, and can take various forms depending on purposes such as use and sale.
  • the second-order dispersion compensation means "compensating for the slope of the dispersion of the wavelength-time characteristic curve described later with reference to FIG. 7A". 7A to compensate for the bending of the wavelength-time characteristic curve described later.
  • Fig. 8 is a diagram illustrating the dispersion versus wavelength characteristics of a single-mode optical fiber (hereinafter, also referred to as SMF), a dispersion compensation fiber, and a dispersion shift fiber (hereinafter, also referred to as DSF).
  • SMF single-mode optical fiber
  • DSF dispersion shift fiber
  • reference numeral 601 is a graph showing the dispersion-wavelength characteristic of the SMF
  • 602 is a graph showing the dispersion-wavelength characteristic of the dispersion compensating fiber
  • 603 is a graph showing the dispersion-wavelength characteristic of 0 SF
  • the vertical axis represents the dispersion. This is a graph with the horizontal axis representing wavelength.
  • the dispersion increases as the wavelength of the light input to the fiber increases from 1.3 m to 1.8 ⁇ m in the SMF, and the wavelength of the input light increases in the dispersion compensation fiber.
  • the variance decreases as the length increases from 1. 3 111 to 1. 7 ⁇ .
  • the dispersion decreases as the wavelength of the input light increases from 1.2 ⁇ to around 1.55 ⁇ , and the wavelength of the input light changes from around 1.55 / ⁇ 111 to 1.8 / xm.
  • the variance increases.
  • DSF in conventional optical communication at a communication bit rate of about 2.5 Gbps (2.5 gigabits per second)
  • dispersion does not cause a problem when the wavelength of the input light is around 1.55 ⁇ .
  • FIGS. 7A to 7C are diagrams mainly explaining a second-order dispersion compensation method.
  • FIG. 7A shows a wavelength-time characteristic and a light intensity-time characteristic
  • FIG. 7B shows a second-order characteristic using an SMF and a dispersion compensating fiber
  • FIG. 7C is a diagram for explaining an example of transmission on a transmission line configured with only SMFs.
  • reference numerals 501 and 511 denote characteristics of signal light before input to the transmission path.
  • 530 is a transmission line composed of SMF 531
  • 502 and 512 are transmissions of signal light having the characteristics of the graphs shown by reference numerals 501 and 511.
  • a graph showing the characteristics of the signal light when the signal light is transmitted through the transmission line 530 and output from the transmission line 530 is shown.
  • a transmission line 520 is composed of the dispersion compensating fiber 52 1 and the SMF 522.
  • 5 13 are graphs showing the signal light characteristics when the signal light having the characteristics of the graphs denoted by reference numerals 501 and 51 1 is transmitted through the transmission line 520 and output from the transmission line 520. It is.
  • Reference numerals 504 and 514 indicate that the signal light having the characteristics of the graphs denoted by reference numerals 501 and 511 is transmitted through the transmission line 520 and output from the transmission line 520, and is described later by the present invention.
  • 6 is a graph showing the characteristics of signal light when the desired third-order dispersion compensation is performed, and almost coincides with the graphs indicated by reference numerals 501 and 511.
  • Graphs 501, 502, 503, and 504 are graphs in which the vertical axis represents wavelength and the horizontal axis represents time (or time), respectively.
  • Graphs 511, 512, 513, 514 Is a graph with the light intensity on the vertical axis and time (or time) on the horizontal axis.
  • Reference numerals 524 and 534 denote transmitters, and 525 and 533 denote receivers.
  • the conventional SMF increases the dispersion as the wavelength of the signal light increases from 1. to 1.8, so the group velocity delay due to dispersion is reduced in high-speed communication and long-distance transmission. Occurs.
  • the signal light is greatly delayed on the long wavelength side as compared with the short wavelength side during transmission, as shown in graphs 502 and 512.
  • the changed signal light may not be able to be received as an accurate signal because it overlaps with the preceding and following signal lights.
  • dispersion is compensated (hereinafter, also referred to as correction) using a dispersion compensating fiber.
  • the conventional dispersion compensating fiber solves the problem of SMF that the dispersion increases as the wavelength increases from 1.3 ⁇ to 1.8 ⁇ , and as described above, the wavelength is 1.3 ⁇ ⁇ . It is designed so that the variance decreases with increasing length from 1.8 ⁇ m to 1.8 ⁇ m .
  • the dispersion compensating fiber can be used, for example, by connecting a dispersion compensating fiber 521 to an SMF 522 as shown by a transmission line 520 in FIG. In the transmission line 520, the signal light is delayed more in the long wavelength side than in the short wavelength side in the SMF 522, and the dispersion compensation
  • the short wavelength side is delayed more than the long wavelength side, As shown in the graphs 503 and 513, the amount of change can be suppressed smaller than the changes shown in the graphs 502 and 512.
  • the chromatic dispersion of the signal light transmitted through the transmission line is represented by the state of the signal light before input to the transmission line, that is, as shown in FIG.
  • Dispersion compensation cannot be performed up to the shape of 0 1, and the limit is to compensate up to the shape of graph 503.
  • graph 503 in the conventional second-order chromatic dispersion compensation method using a dispersion compensation fiber, the light of the central wavelength of the signal light is compared with the light of the short wavelength side and the light of the long wavelength side. Without delay, only the light of the component on the shorter wavelength side and the longer wavelength side than the light of the central wavelength component of the signal light is delayed. Then, as shown in the graph 513, a ripple may be generated in a part of the graph.
  • the optical fiber is simply referred to as fiber.
  • the third-order dispersion compensation which is the subject of the present invention, cannot be performed.
  • third-order dispersion is increasingly recognized as a major problem, and compensation for it is becoming an important issue.
  • Many attempts have been made to solve the third-order dispersion compensation problem, but a third-order dispersion compensator or compensation method that can sufficiently solve the conventional problems has not yet been put into practical use.
  • An example using a fiber formed with a diffraction grating as a method of compensating for third-order dispersion has been reported, but it has fatal disadvantages such as the inability to perform necessary compensation, large loss, and large dimensions.
  • the price is high and practical application is not expected.
  • the present inventors have proposed a dispersion compensating element using a multilayer film such as a dielectric, which has been proposed separately from the present invention, and succeeded in third-order dispersion compensation.
  • a dispersion compensating element using a multilayer film such as a dielectric which has been proposed separately from the present invention.
  • third-order dispersion compensation is ideally performed when the communication bit rate is increased to 4 OGb ps or 80 Gb ps, for example.
  • the present inventors have proposed a third-order dispersion compensator capable of adjusting the wavelength band of the group velocity delay and the delay time of the group velocity delay separately from the present invention.
  • a third-order or higher-order dispersion compensating element that performs dispersion compensation suitable for each channel wavelength is a wavelength-tunable dispersion compensation (that is, a dispersion compensation target wavelength can be selected).
  • a compensation element has been proposed.
  • the present invention has been made in view of such a point, and an object of the present invention is to provide a wide dispersion which has not been practically used in the past and a sufficient dispersion compensation over a wavelength range, particularly a third-order dispersion.
  • An optical dispersion compensator with excellent group velocity delay time-wavelength characteristics that can perform compensation is provided at a low cost in a state of high reliability and suitable for mass production.
  • a dispersion compensation method and a dispersion compensation element that enable third- or higher-order dispersion compensation using a multilayer element having a band and delay time adjustment function, or a combination of second- and third-order dispersion compensation. It is an object of the present invention to provide a dispersion compensation method and a dispersion compensation element that can be performed.
  • the object of the present invention is as follows: o band (1260-1360 nm), E-band (1360-1460 nm), S-band (1460-1530 nm), C-band (1 530—1565 nm), L—band (1 565— At least one extreme value in at least one of the wavelength bands of each band called the U-band (16625 nm)
  • An object of the present invention is to configure a dispersion compensating element using a multilayer film having a group velocity delay time-wavelength characteristic curve and to realize accurate dispersion compensation in each communication wavelength range.
  • the optical dispersion compensating element is designed to have a group velocity delay time-wavelength characteristic capable of compensating for the above-mentioned dispersion occurring in communication over a wavelength band of several tens of nm that has not been practically used in the past. It is an object of the present invention to provide a light dispersion compensation method using a low-cost, highly reliable and small communication system capable of compensating the dispersion of the entire signal light using the light dispersion compensation element. Disclosure of the invention
  • the present invention relates to a dispersion compensating element, and also relates to a dispersion compensating method for compensating dispersion by constructing a dispersion compensating element substantially equivalent to the dispersion compensating element of the present invention.
  • the content of the dispersion compensating element of the present invention will be described as the dispersion compensating element used in the dispersion compensation method of the present invention, and will also serve as the description of the dispersion compensating method.
  • the most significant feature of the dispersion compensating element used in the dispersion compensation method of the present invention is that at least two elements capable of performing dispersion compensation or at least two parts of the element capable of performing dispersion compensation (hereinafter, referred to as The element capable of performing dispersion compensation and the element capable of performing dispersion compensation are collectively referred to as an element capable of performing dispersion compensation), and are connected in series along the optical path of signal light. That is, it has a dispersion compensation element using a multilayer film (hereinafter, also simply referred to as a multilayer film element).
  • a multilayer film element hereinafter, also simply referred to as a multilayer film element
  • the element capable of performing the dispersion compensation uses a group velocity delay time-wavelength characteristic of a multilayer film.
  • An optical dispersion compensating element capable of performing dispersion compensation by performing the method wherein the group velocity delay time-wavelength characteristic curve of the multilayer film has at least one pole in a wavelength band to be subjected to dispersion compensation or in a wavelength region in the vicinity thereof.
  • the group velocity delay time of the optical dispersion compensating element used in the optical dispersion compensating method of the present invention is used in the optical dispersion compensating method of the present invention.
  • the shape of the wavelength characteristic curve differs from the group velocity delay time-wavelength characteristic curve of the element capable of performing dispersion compensation, which constitutes the optical dispersion compensation element used in the optical dispersion compensation method of the present invention, in general. ing.
  • the optical dispersion compensating element of the present invention having the multilayer film can basically be applied to any wavelength range.
  • the present invention provides a great effect by using an optical dispersion compensating element using a multilayer film having a group velocity delay time-wavelength characteristic curve having at least one extreme value in a wavelength range of 1260 to 1700 nm which is currently being watched. Can be raised.
  • a dispersion compensating element using a multilayer film having a group velocity delay time-wavelength characteristic curve having an extreme value can be configured, and accurate dispersion compensation can be performed in each communication wavelength range.
  • an optical dispersion compensating element of the present invention is an optical dispersion compensating element that can be used for optical communication using an optical fiber in a communication transmission path and can compensate for dispersion as chromatic dispersion.
  • a structure in which a plurality of elements or at least a plurality of parts of the element capable of performing dispersion compensation as an element capable of performing dispersion compensation are connected in series along the optical path of the signal light. It is characterized by
  • optical dispersion compensating element of the present invention is characterized in that there are a plurality of connection methods or connection paths of the plurality of elements capable of performing dispersion compensation.
  • optical dispersion compensating element of the present invention is characterized in that a connection method or a connection path of the plurality of elements capable of performing dispersion compensation can be selected from outside the optical dispersion compensating element.
  • Examples of the optical dispersion compensating element of the present invention include a device capable of performing the plurality of dispersion compensation. It is characterized in that the method of connecting the element includes a method by reflection on the incident surface of the multilayer film element arranged oppositely.
  • optical dispersion compensating element of the present invention is that the means for selecting the connection method or the connection path of the plurality of elements capable of performing dispersion compensation from outside the optical dispersion compensating element is an electric means.
  • an optical dispersion compensation method for performing communication by compensating for dispersion in optical communication using an optical fiber in a communication transmission line, comprising: A plurality of devices capable of performing dispersion compensation as a multilayer device using a multilayer film having at least three reflective layers having different ratios and at least two light transmitting layers formed between the reflective layers are provided. Alternatively, at least a plurality of portions of the element capable of performing dispersion compensation as an element capable of performing dispersion compensation are connected in series along the optical path of the signal light to the optical dispersion compensating element. This is characterized in that dispersion compensation is performed by injecting light.
  • An example of the optical dispersion compensation method of the present invention is to pass signal light transmitted through an optical fiber through the optical dispersion compensation element before wavelength separation for each receiving channel to compensate for at least tertiary dispersion. It is characterized by:
  • An example of the optical dispersion compensating method of the present invention is as follows.
  • An optical dispersion compensating element configured by connecting a plurality of elements capable of performing the dispersion compensation in series is 1260 to 1360 nm, 1336 0 to 1460 nm, 1460 to 1550 nm, 1530 to: 1565 nm, 1565 to 1625 nm, 1625 to 1670 It is characterized by having a group velocity delay time-wavelength characteristic curve having at least one extreme value in at least one wavelength range of a wavelength range of 5 nm.
  • An example of the optical dispersion compensation method according to the present invention is characterized in that a plurality of types of connection methods of elements capable of performing dispersion compensation in the optical path of signal light can be selected.
  • An example of the optical dispersion compensation method of the present invention is that the multilayer film used in at least one element capable of performing dispersion compensation constituting the optical dispersion compensation element has a center wavelength of incident light;
  • the thickness of each layer of the multilayer film when considered as an optical path length for the light of the above is a multilayer film having a thickness of a value almost an integral multiple of ⁇ / 4, and the multilayer film has a thickness of ⁇ .
  • the layer H is composed of a plurality of layers in which the layer L is combined, and the layer H is any one of S i, G e, T i 0 2 , T a 2 ⁇ 5 , and N b 2 O s It is characterized by being formed of a layer consisting of
  • An example of the optical dispersion compensation method of the present invention is such that at least one of the multilayer devices has a thickness of at least one stacked film constituting a multilayer film of the multilayer device, and the film thickness of the multilayer film is parallel to a light incident surface of the multilayer film.
  • This is characterized by a multilayer film element using a multilayer film that changes in the in-plane direction in a simple cross section, that is, in the in-plane direction of incidence.
  • An example of the optical dispersion compensation method of the present invention is characterized in that the layer L is formed using a material having a lower refractive index than the material used for the layer H.
  • the layer L is characterized by being formed by a layer consisting of S I_ ⁇ 2.
  • An example of the optical dispersion compensation method according to the present invention is characterized in that at least one multilayer film has at least two film thickness change directions in the in-plane direction of the multilayer film. I have.
  • An example of the optical dispersion compensation method of the present invention includes an adjusting unit that engages with an element capable of performing the dispersion compensation and adjusts a film thickness of at least one laminated film of the multilayer film.
  • a special feature is that means for changing the light incident position on the incident surface of the film is provided.
  • At least one kind of a multilayer film (described later) can be used as the multilayer film. That is, a multilayer film having at least five types of laminated films having different optical properties (that is, at least five layers having different optical properties such as light reflectance and film thickness).
  • a multilayer film having at least five types of laminated films having different optical properties that is, at least five layers having different optical properties such as light reflectance and film thickness.
  • the one of the three types of reflective layers and the one of the two light transmitting layers are alternately arranged, and the multilayer film is a first layer in order from one side in a thickness direction of the film.
  • the first layer as a reflection layer
  • the second layer as a first light transmission layer
  • the third layer as a second reflection layer
  • the fourth layer as a second light transmission layer
  • the third reflection layer
  • the center wavelength of the incident light is defined as ⁇ , and in the first to fifth layers, it is considered as the center wavelength of the incident light; the optical path length for L light (hereinafter, also simply referred to as the optical path length).
  • Force S an integral multiple of / 4 ⁇ 1%
  • the film thickness of the multilayer film is 1/4 times I (hereinafter, ⁇ 1% of 1/4 times ⁇ ).
  • a layer having a higher refractive index (hereinafter referred to as a layer having a thickness of 1/4 times L) (hereinafter also referred to as a layer)) and a layer having a lower refractive index having a thickness of 1/4 times (hereinafter referred to as a layer).
  • L also known as L).
  • the multilayer film ⁇ is a layer in which the five-layer laminated film, that is, the first to fifth layers are combined one by one in the order of layer H and layer L in order from one side in the thickness direction of the multilayer film.
  • HL layer also referred to as HL layer 3 sets (a layer combining the layer HI layer and the layer L 1 layer is referred to as an HL layer 1 set; the same applies hereinafter).
  • the second layer and the layer L which are formed by laminating 10 sets of the layer H and the layer obtained by combining the layer H (that is, the layer formed by laminating two layers H, hereinafter also referred to as the HH layer), 3rd layer composed of 7 sets of layers and HL layers, 4th layer composed of 38 sets of HH layers, 1 layer and 13 layers of HL
  • a multi-layered film composed of a set and a fifth layer formed by laminating
  • the multilayer film B is replaced by a film having the same direction as that of the multilayer film A.
  • the layer of LL is also referred to) 3 sets of HH layers, 3 sets of LL layers, 2 sets of LL layers, and 1 set of HH layers as a multilayer film formed by laminating in this order.
  • the fourth layer is the same as in the case of the multilayer film A.
  • Direction in order from one side in the thickness direction of the film, 3 sets of HH layers, 3 sets of LL layers, 3 sets of HH layers 3 sets, 3 sets of LL layers, 3 sets of HH layers, 3 sets of LL layers, 3 sets of HH layers, 3 sets of LL layers, 3 sets of HH layers, 3 sets of LL layers, 3 sets of HH layers Set, 3 sets of LL layers, 3 sets of HH layers, 3 sets of LL layers, 2 sets of HH layers A multilayer film,
  • a layer in which the multilayer film D is formed by laminating the five-layered film that is, the first to fifth layers in this order from one side in the thickness direction of the multilayer film, and combining layers one by one in the order of layer H.
  • the first layer consists of five sets of LH layers
  • the second layer consists of seven sets of LL layers, one layer H and one layer of LH.
  • 3rd layer composed of 7 sets and 4 layers composed of 5 7 layers of LL, 1 layer H and 13 layers of LH laminated
  • Each layer is formed by the fifth layer
  • the multilayer film F is replaced by a “film” in the same direction as in the case of the multilayer film E. From one side in the thickness direction '', 3 sets of HH layers, 3 sets of LL layers, 3 sets of HH layers, 3 sets of LL layers, 2 sets of HH layers A set, one set of LL layers and one set of HH layers are laminated in this order to form a multilayer film formed of a laminated film,
  • the fourth layer has the same direction as that of the multilayer film E.
  • the first layer consists of four sets of LH layers
  • the second layer consists of nine sets of LL layers, one layer H and six layers of LH.
  • the third set consisting of stacking sets Layer, a fourth layer composed of 35 sets of LL layers, and a fifth layer composed of one layer H and 13 layers of LH layers. Multi-layer film.
  • FIG. 1 is a diagram illustrating optical dispersion compensation according to the present invention.
  • FIG. 2 is a cross-sectional view of the multilayer film of the present invention.
  • FIG. 3 is a perspective view of the multilayer film of the present invention.
  • FIG. 4 is a group velocity delay time-wavelength characteristic curve of the multilayer film of the present invention.
  • FIG. 5A is a graph showing a group velocity delay time-wavelength characteristic of one element capable of performing dispersion compensation, which is a basic element of the dispersion compensation element of the present invention.
  • FIG. 5B is a diagram illustrating a method of improving the group velocity delay time-wavelength characteristic using a plurality of elements capable of performing dispersion compensation according to the present invention.
  • FIG. 5C is a diagram for explaining a method of improving the group velocity, the delay time and the wavelength characteristic by using a plurality of elements capable of performing the dispersion compensation according to the present invention, and the element capable of performing the dispersion compensation.
  • 6 is a graph showing the group velocity delay time versus wavelength characteristic of the optical dispersion compensating element of the present invention in which three are connected in series.
  • FIG. 5D is a diagram illustrating a method of improving the group velocity delay time one wavelength characteristic using a plurality of elements capable of performing dispersion compensation according to the present invention.
  • 6 is a graph showing the group velocity delay time versus wavelength characteristic of the optical dispersion compensating element of the present invention in which three are connected in series. .
  • FIG. 6A is a diagram illustrating an example of the optical dispersion compensating element of the present invention, and illustrates an example in which two elements capable of performing dispersion compensation are connected in series to form an optical dispersion compensating element.
  • FIG. 6A is a diagram illustrating an example of the optical dispersion compensating element of the present invention, and illustrates an example in which two elements capable of performing dispersion compensation are connected in series to form an optical dispersion compensating element.
  • FIG. 6B is a diagram illustrating an example of the optical dispersion compensating element of the present invention, and illustrates an example in which three elements capable of performing dispersion compensation are connected in series to form an optical dispersion compensating element.
  • FIG. 6B is a diagram illustrating an example of the optical dispersion compensating element of the present invention, and illustrates an example in which three elements capable of performing dispersion compensation are connected in series to form an optical dispersion compensating element.
  • FIG. 6C is a diagram for explaining an example of the optical dispersion compensating element of the present invention.
  • the multilayer film whose film thickness changes in the incident plane direction, two signal light incident positions are shown.
  • FIG. 4 is a diagram illustrating an example in which an optical dispersion compensating element is configured by being connected in series along a navigation route.
  • FIG. 6D is a diagram illustrating an example of the optical dispersion compensating element of the present invention, and is a diagram illustrating an example in which the optical dispersion compensating element of the present invention is mounted in one case.
  • FIG. 7A is a diagram for explaining a method of compensating for second and third order chromatic dispersion, and is a diagram for explaining a wavelength-time characteristic and a light intensity-time characteristic.
  • FIG. 7B is a diagram for explaining a method for compensating the second and third order chromatic dispersion, and is a diagram for explaining a transmission path.
  • FIG. 7C is a diagram illustrating a method of compensating for the second and third order chromatic dispersion, and is a diagram illustrating a transmission path.
  • FIG. 8 is a graph showing dispersion-wavelength characteristics of a conventional optical fiber.
  • FIG. 9A is a plan view showing another embodiment of the present invention.
  • FIG. 9B is a front view of the embodiment. BEST MODE FOR CARRYING OUT THE INVENTION
  • Fig. 1 is a diagram illustrating a method of compensating dispersion generated in communication using an optical fiber as a transmission line with an optical dispersion compensator.
  • Reference numeral 111 denotes signal light remaining after compensating for secondary dispersion.
  • the group velocity delay time vs. wavelength characteristic curve showing the third order dispersion of the dispersion compensating element, 1102 is the group velocity delay time vs. wavelength characteristic curve of the dispersion compensating element, and 1103 is the signal having the dispersion characteristic of curve 1101.
  • the delay time and the horizontal axis are wavelength.
  • FIG. 2 to 4 are diagrams for explaining the optical dispersion compensating element according to the present invention.
  • FIG. 2 is a cross-sectional view of a multilayer film described later
  • FIG. 3 is a perspective view of a multilayer film having a changed film thickness
  • FIG. 5 is a graph showing a group velocity delay time versus wavelength characteristic curve of a multilayer film.
  • FIG. 2 is a diagram schematically illustrating a cross section of a multilayer film used as an example of the tertiary dispersion compensation element of the present invention.
  • reference numeral 100 denotes a multilayer film as an example of the optical dispersion compensating element of the present invention
  • 101 denotes an arrow indicating the direction of incident light
  • 102 denotes an arrow indicating the direction of output light
  • 103 104 is a reflective layer having a reflectivity of less than 100% (hereinafter also referred to as a reflective film)
  • 105 is a reflective layer having a reflectivity of 98 to: L 00%
  • 108 and 109 are light
  • the transmission layer, 1 1 1 and 1 1 2 are cavities.
  • reference numeral 107 denotes a substrate, for example, which is made of 117 glass.
  • the reflectances R (103), R (104), and R (105) of each of the reflective layers 103, 104, and 105 in FIG. 2 are R (103) ⁇ R (1 04) ⁇ R (1 05). It is preferable in terms of mass production that the reflectance of each layer is set to be different from each other at least between the reflective layers adjacent to each other with the light transmitting layer interposed therebetween. That is, incident light is incident
  • the reflective layer is formed so that the reflectance of each reflective layer with respect to the central wavelength L of the incident light gradually increases from the side toward the thickness direction of the multilayer film.
  • the reflectance of each reflective layer with respect to the wavelength; I light is defined as 60% ⁇ R (103) ⁇ 77%, 96% ⁇ R (104) ⁇ 99.8%, 98% ⁇ R (105).
  • the group velocity delay time-wavelength characteristic curve as shown in FIGS. Obtainable. It is more preferable that R (10 3) ⁇ R (104) ⁇ R (105), and it is more preferable that R (105) be close to or equal to 100%. Performance can be further enhanced.
  • each reflective layer it is preferable to select the conditions for forming each reflective layer so that the intervals when considered as the optical path length between adjacent reflective layers are different from each other, The design accuracy of the reflectance of each reflective layer can be relaxed, and the film thickness is the wavelength; a combination of unit films of 1/4 of I (films with an integral multiple of ⁇ / 4) A multilayer film used for a dispersion compensator can be formed, and a third-order dispersion compensator having high reliability and excellent mass production I "can be provided at low cost.
  • the thickness of the unit film of the multilayer film is described to be a quarter of the wavelength, this is within the range of an error allowed in the formation of the film in mass production, as described above. 4 means that the present invention is at ⁇ / 4 ⁇ 1%; it means a film thickness of I / 4, and even in this range, the present invention has a particularly great effect. Emit. Therefore, in the present invention, the film thickness in this range is referred to as 1/4 thickness.
  • the thickness of the above unit film to /4 ⁇ 0.5% (in this case, I-no 4 has no error; meaning ⁇ 4), there is little variation without impairing mass productivity.
  • an optical dispersion compensating element as described later with reference to FIGS. 5A to 5D and FIGS. 6A to 6D can be provided at low cost.
  • the multi-layer film according to the present invention is described as being formed by laminating unit films having a thickness of ⁇ / 4. This is a method of forming one unit film and then forming the next unit film. Force that can form a multi-shear film by repeating this process. In general, a film with a thickness of an integral multiple of fly / 4 is continuously formed. Such a multilayer film is naturally included in the multilayer film of the present invention. Then, some examples of the multilayer film of the present invention could be formed by using a film forming step of continuously forming the reflection layer and the transmission layer.
  • FIG. 3 is a diagram illustrating an example in which the thickness of the multilayer film 100 is changed in an in-plane direction of a later-described incident surface 220 of the multilayer film 100 of FIG.
  • reference numeral 200 denotes a multilayer film as an example of the optical dispersion compensating element of the present invention
  • 201 denotes a first reflective layer
  • 202 denotes a second reflective layer
  • 203 denotes a third reflective layer.
  • a reflective layer 205 is a substrate, 206 is a first light transmitting layer, 207 is a second light transmitting layer, 211 is a first cavity, 211 is a second cavity, 220 is the light incident surface, 230 is the arrow indicating the direction of the incident light, 240 is the arrow indicating the direction of the emitted light, 250 is the arrow indicating the direction of the first film thickness change, 26 0 is an arrow indicating a second film thickness change direction, and 270 and 271 are arrows indicating a direction in which an incident position of incident light is moved.
  • a third reflection layer 203 for example, on a substrate 205 made of, for example, BK-7 glass (trade name of Schott, Germany), a third reflection layer 203, a second light transmission layer 207, The second reflection layer 202, the first light transmission layer 206, and the first reflection layer 201 are sequentially formed.
  • the multilayer film is formed so that the thickness of the layer 207 changes in the direction indicated by the arrow 260 (the thickness gradually increases from the front of the figure to the other side).
  • the thicknesses of the first to third reflective layers are the first, second, and third when the wavelength when the resonance wavelengths of the first and second cavities match the center wavelength of the incident light; L.
  • the film thickness is formed such that the reflectance of each reflective layer of No. 3 satisfies the same conditions as the conditions of R (103), R (104) and R (105).
  • FIG. 4 shows a multilayer film (hereinafter also referred to as a light dispersion compensation element) 200 as an example of the light dispersion compensation element of the present invention.
  • a light dispersion compensation element a multilayer film (hereinafter also referred to as a light dispersion compensation element) 200 as an example of the light dispersion compensation element of the present invention.
  • Light is incident, the emitted light is obtained in the direction of arrow 240, and the group velocity when the incident position of the incident light is moved in the direction of arrow 270 or 271 in Fig. 3 as described later When delayed
  • This is for explaining the manner in which the inter-wavelength characteristic curve changes.
  • Fig. 4 shows the group velocity delay time vs. wavelength characteristic curve when the incident light having the center wavelength; L is incident on the incident position 280 to 282, the vertical axis represents the group velocity delay time, and the horizontal axis represents the wavelength. It is.
  • the wavelength giving the extreme value in the group velocity delay time-wavelength characteristic curve 2801 of the substantially symmetrical shape in FIG. 4 changes, and from that position in the direction indicated by the arrow 271 When the incident position is moved, the wavelength; L.
  • the shape of the group velocity delay time-wavelength characteristic curve can be changed as shown by the curves 2811 and 2812 in FIG.
  • Each curve in FIG. 4 is obtained when the film thickness of each film is monotonically increased in the directions of arrows 250 and 260 in FIG.
  • Band center wavelength at curve 2801-1282 Is set at an appropriate wavelength in the graph of FIG. 4 for the purpose of dispersion compensation, but may be, for example, approximately the center of the wavelength range of the curve shown in FIG. It may be determined appropriately according to the purpose. In addition, it is not necessary to check the correspondence between the wavelengths of the characteristic points of the curve, such as the extreme wavelengths of the curves 2801-128, in advance. is there.
  • the center wavelength of the incident light to be dispersion-compensated the band center wavelength ⁇ corresponding to I.
  • the incident position of the incident light is moved in the direction of arrow 270 so as to match, and the content of the guarantee to be compensated for dispersion, that is, the dispersion situation of the incident light is adapted and used for dispersion compensation
  • the shape of the group velocity delay time-wavelength characteristic curve is selected from, for example, the curves in Fig. 4, and the incident position is set in the direction indicated by the arrow 271 in Fig. 3 accordingly.
  • tertiary dispersion compensation is performed using the optical dispersion compensating element of the present invention, for example, using the curve 2801.
  • the second-order minute dispersion compensation can be performed by using a portion of the curve 2811 or 2812 that is relatively close to a linear component.
  • the wavelength bandwidth of dispersion compensation that can be compensated by itself as an “element capable of performing a dispersion compensating element” is around 1.5 nm for the signal light whose wavelength is around 1.55 im, and the group velocity delay time is 3 In many cases, this is in the order of ps (picoseconds), and if the wavelength bandwidth of dispersion compensation is widened to support multiple channels of optical communication, the group velocity delay time is short enough to allow sufficient dispersion compensation. It is difficult to obtain, and it is desirable that further improvements be made in order to use it widely and practically in actual communications. Therefore, the present invention will be described in more detail with reference to FIGS. 5A to 5D and FIGS. 6A to 6D.
  • FIGS. 5A to 5D are diagrams illustrating a method of improving the group velocity delay time-wavelength characteristic by using a plurality of elements capable of performing dispersion compensation as described above, for example, and FIG. 5A is used in the present invention.
  • Figure 5B shows the shape of the group velocity delay time vs. wavelength characteristic curve, and the peak of the group velocity delay time vs. wavelength characteristic curve.
  • Figure 5C shows the group velocity delay-time-wavelength characteristic curve of the optical dispersion compensating element of the present invention in which three elements capable of performing dispersion compensation with almost the same characteristic and different extreme wavelengths are connected in series.
  • Figure 5D shows the group velocity The group velocity delay time vs. wavelength characteristic of the optical dispersion compensating element used in the optical dispersion compensation method of the present invention in which three elements capable of performing dispersion compensation differing in the shape of the delay time versus wavelength characteristic curve and the extreme wavelength are connected in series.
  • the vertical axis represents the group velocity delay time
  • the horizontal axis represents the wavelength.
  • reference numerals 301 to 309 denote the group velocity delay time-wavelength characteristic curves of one element capable of performing dispersion compensation used in the present invention
  • 310 denotes the present invention.
  • 311 is almost the same shape of the group velocity delay time-wavelength characteristic curve used in the present invention.
  • the extremum of the group velocity delay time of the group velocity delay time vs. wavelength characteristic curve 310 is 1.6 times that of a single element capable of performing dispersion compensation
  • the wavelength band to be compensated is about 1.8 times
  • the extremum of group velocity delay time vs. wavelength characteristic curve 3 1 1 is about 2.3 times that of a single group velocity delay time.
  • the bandwidth is about 2.5 times that of a single device that can perform dispersion compensation.
  • the extreme value of the group velocity delay time in the curve of the group velocity delay time-wavelength characteristic 312 is about three times the wavelength band for dispersion compensation, which is about three times that of a single element that can perform dispersion compensation.
  • the area is about 2.3 times that of a single element capable of performing dispersion compensation.
  • the extreme value of the group velocity delay time of the group velocity delay time-wavelength characteristic curve of the element capable of performing dispersion compensation using a multilayer film as described in FIGS. It varies depending on the configuration conditions of each reflection layer and each light transmission layer of the multilayer film. For example, the wavelength band for dispersion compensation is relatively wide as shown by the curve 307 in FIG. Group velocity delay-wavelength characteristic curve where the value is not too large, or the group velocity delay time-wavelength characteristic curve where the wavelength band for dispersion compensation is narrow but the extreme value of the group velocity delay time is large as shown by curve 308 In addition, it is possible to realize an element capable of performing dispersion compensation having various characteristics.
  • Multilayer films used in an element capable of performing such dispersion compensation include, for example, the multilayer films A to H described in the section of “Disclosure of the Invention”.
  • the extreme value of the group velocity delay time was 3 ps (picoseconds) for signal light with a wavelength of about 1.55 ⁇ m.
  • a group velocity delay time-wavelength characteristic curve with a dispersion compensation wavelength band of 1.3 to 2.0 nm was realized.
  • a plurality of devices capable of performing this dispersion compensation are connected in series, and the wavelength band for dispersion compensation having a group velocity delay-one wavelength characteristic capable of compensating for dispersion due to optical fiber transmission is 15 nm. Can be realized.
  • This + optical dispersion compensating element is used as a third-order dispersion compensating element for a 30-channel communication system in which the wavelength is around 1.55 ⁇ and the bandwidth of each channel is 0.5 nm and the bandwidth is 0.5 nm.
  • the group velocity delay time vs. wavelength characteristic curve in FIG. 4 and the group velocity delay time vs. wavelength characteristic curve in FIG. By properly selecting the wavelength characteristics, not only the third-order dispersion but also the second-order dispersion could be compensated.
  • the example of the optical dispersion compensating element in which at least two elements capable of performing dispersion compensation of the present invention are connected in series has a group velocity delay time-wavelength characteristic necessary for compensating third-order or higher dispersion.
  • the signal light in an element capable of performing dispersion compensation by changing the thickness of the light transmitting layer and the reflecting layer of the multilayer film in the direction of the incident plane.
  • the group velocity delay time-wavelength characteristic of the element capable of performing dispersion compensation can be raised.
  • the means for changing the incident position of the incident light is realized by moving at least one of the optical dispersion compensating element 200 or the incident position itself of the incident light with respect to the position of the incident light.
  • the light dispersion compensating element or means for moving the incident light various choices can be made depending on the circumstances, such as the circumstances in which the light dispersion compensating element is used, the cost, and the characteristics.
  • the incidence position can be easily and accurately selected by using a prism and a two-core collimator that can be combined with these methods, or by selecting the incidence position by an optical means such as using an optical waveguide. be able to.
  • each layer of the multilayer film of the element capable of performing dispersion compensation used for optical dispersion compensation device of the present invention the thickness created by the wave of S I_ ⁇ 2 of ion-assisted deposition of 4 minutes film (hereinafter, Ion'ashisu Layer L), and a layer H formed of a TiO 2 ion-assisted film having a quarter wavelength thickness.
  • S i ⁇ 2 ions (the layers) assist film called layer 1 set of LH in one layer and T i O 2 of the ion assist film (layer H) 1-layer combination layer of, for example, a layer of "LH 5 "Laminating a set” means "layer L, layer H, layer L, layer H, layer L, layer H, layer L, layer H, layer H, layer H, layer H, layer one by one. It means that.
  • the layer of the LL is called the thickness was formed overlapping two layers L which is composed of the ion-assisted film S I_ ⁇ 2 quarter wavelengths layer substantially set of LL. Therefore, for example, “three layers of LL are stacked” means “formed by stacking six layers L”.
  • the present invention is not limited thereto, as the same dielectric material as T i 0 2
  • T io 2 , T a 2 ⁇ 5, N b 2 ⁇ 5 or the like can be used, further, in addition to the dielectric material, it is also possible to form a layer H with S i and G e.
  • S i 0 2 was shown as the composition of the layer L
  • S i ⁇ 2 is a force S that has the advantage of being able to form the layer L at low cost and high reliability.
  • the present invention is not limited to this. Not If the layer L is formed of a material whose refractive index is lower than the refractive index of the layer H, a light dispersion compensating element exhibiting the above effects of the present invention can be realized.
  • the layer L and the layer H constituting the multilayer film are formed by ion-assisted vapor deposition, but the present invention is not limited to this, and ordinary vapor deposition, sputtering, ion plating, and the like are performed.
  • the present invention exerts a great effect even when a multilayer film formed by the above method is used.
  • the light dispersion compensating element of the present invention can be used by appropriately holding a wafer-like element such as a multilayer film 200 as a light dispersion compensating element shown in FIG.
  • a wafer-like element such as a multilayer film 200
  • the chip is cut into small pieces.
  • the form has various possibilities, for example, it can be used as a compensating element. In any case, the main effects described in the present invention can be obtained.
  • FIGS. 6A to 6D are diagrams for explaining an example of the optical dispersion compensating element of the present invention
  • FIG. 6A is a diagram illustrating a configuration of an optical dispersion compensating element by connecting two elements capable of performing the dispersion compensation in series.
  • FIG. 6B shows an example in which three elements capable of performing the dispersion compensation are connected in series to form a light dispersion compensation element
  • FIG. 6C shows a case where the film thickness changes in the direction of the incident plane.
  • Figure 6D shows an example in which two points of incidence of signal light are connected in series along the signal light path on a multilayer film to form an optical dispersion compensator.
  • FIG. 9 is a diagram showing an example in which a dispersion compensating element is mounted in one case.
  • reference numerals 410, 420, 430, and 440 denote optical dispersion compensating elements of the present invention
  • 411, 412, 421 to 423, 442, and 443 denote elements capable of performing dispersion compensation
  • 416 denotes a dispersion compensation element.
  • Multilayer films used in devices that can be used are optical fibers, 413, 4131, 414, 4141, 424, 425, 434, Reference numerals 435, 444, and 445 denote arrows indicating the traveling direction of the signal light, reference numeral 417 denotes a lens, reference numeral 418 denotes a two-core collimator comprising a lens 417 and optical fibers 4151 and 4152, reference numeral 441 denotes a case, and reference numeral 431 denotes an incident surface.
  • Performing wafer-shaped dispersion compensation which is configured so that dispersion compensation can be performed by forming a multilayer film whose thickness changes inward on the substrate 432 and 433 are “elements that can perform dispersion compensation”, respectively.
  • the signal light that has entered in the direction of arrow 4 13 enters the element 4 11 that can perform dispersion compensation, and the element 4 1 that can receive dispersion compensation and perform dispersion compensation. Emitted from 1 and transmitted through fiber 4 15 to be able to perform dispersion compensation Entering element 4 12, and then subjected to dispersion compensation again to be able to perform dispersion compensation 4 2
  • the optical fiber 4 15 is transmitted in the direction of the arrow 4 14.
  • Reference numeral 4112 is a cross-sectional view for explaining the internal structure of a portion of the element 411 capable of performing dispersion compensation, which is surrounded by the curve 4111.
  • the optical fibers 4 15 1 and 4 15 2 and the lens 4 17 constitute a two-core collimator 4 18, and the signal light that has traveled along the optical fiber 4 15 1 in the direction of the arrow 4 1 3 1 is a lens 4 17 Pass through and enter the multilayer film 4 16.
  • the multilayer film 4 16 has the group velocity delay time-wavelength characteristic shown in FIG. 5A, and the signal light that has entered the multilayer film 4 16 through the optical fiber 4 15 1 and the lens 4 17.
  • Is subjected to tertiary dispersion compensation passes through the reproduction lens 4 17, enters the optical fiber 4 15 2, travels in the direction of the arrow 4 1 4 1, and is capable of performing dispersion compensation 4 1 It is incident on 2.
  • the signal light that has been further subjected to dispersion compensation by the element 4 12 capable of performing dispersion compensation exits from the element 4 12 capable of performing dispersion compensation, and passes through the optical fiber 4 15 with an arrow 4 1 4 The light is emitted in the direction indicated by.
  • the optical dispersion compensating element 410 of the present invention shown in FIG. 6A has the group velocity delay time-wavelength characteristic shown in FIG. 5B, and the signal light incident on the optical dispersion compensating element 410 Is subjected to dispersion compensation according to the group velocity delay time-wavelength characteristic shown in FIG. 5B, and is emitted from the optical dispersion compensating element 410.
  • the signal light that has entered the optical dispersion compensating element 420 from the direction of the arrow 424 is also capable of performing dispersion compensation.
  • dispersion compensation is performed according to the group velocity delay time vs. wavelength characteristic curve as shown in FIG.
  • the optical fiber 4 26 travels in the direction indicated by the arrow 4 25.
  • Fig. 6C shows the part of the element 431 that can perform dispersion compensation formed on the same wafer instead of the elements 411 and 4122 that can perform dispersion compensation in Fig. 6A.
  • the optical dispersion compensator 430 is an example in which 4 3 2 and 4 3 3 are connected in series along the signal light path using an optical fiber 4 36. This is the same as described in the above. However, it is clear from the above description that the method of dispersion compensation is different depending on the group velocity delay time-wavelength characteristic of the element capable of performing dispersion compensation.
  • FIG. 9A and 9B show a modification of FIG. 6C.
  • a semiconductor substrate 700 is used as a substrate of the element 431 capable of performing dispersion compensation, and the portions 432 and 433 of the element 431 capable of performing dispersion compensation.
  • the movable parts 720 and 703 arranged in a matrix in the vertical and horizontal directions are formed on the surface on which the movable parts are arranged.
  • An even number of elements hereinafter, also referred to as a matrix element plate in which elements capable of performing dispersion compensation, which are elements using a multilayer film as described above (also referred to as a multilayer element) are formed.
  • an electrode is arranged on the movable portion on the matrix-like element plate.
  • the inclination on the surface of the matrix-like element plate changes according to the state of the voltage applied to the electrode. Therefore, the perpendicular direction of the incident surface of the element on which the dispersion compensation can be performed is changed.
  • the even number of matrix element plates 7 1 1 and 7 1 2 are appropriately placed two by two with the incident surfaces of the elements capable of performing dispersion compensation formed thereon facing each other. They are arranged so as to be alternately incident on the opposing matritas-like element plates 71 1, 71 2. Then, the inclination of the incident surface of the element capable of performing each dispersion compensation on the opposing matrix-shaped element plate is controlled as necessary, and dispersion compensation is performed as an optical path through which the signal light passes.
  • the characteristics and number of elements that can perform dispersion compensation are selected, and the group velocity delay time vs. wavelength characteristic curve as illustrated in Figs. Can be realized.
  • the optical connection between the elements capable of performing each dispersion compensation is performed by disposing the input / output terminals as the entire dispersion compensating element or by opposing each of the two elements.
  • the optical path between the incident surfaces of the elements capable of performing the dispersion compensation on the matrix-like element plates arranged opposite to each other can be configured to be performed by reflection between the respective incident surfaces.
  • 100 ⁇ 10 that is, 100 elements capable of performing dispersion compensation are formed on each of the matrix element plates, and two such matrix element plates are opposed to each other as described above.
  • three sets of elements can be formed, and dozens to hundreds of elements can be compensated, including optical path formation by reflection between elements that can perform dispersion compensation and optical path formation by a fiber collimator. Are connected in series in the optical path of the signal light to form an optical path, thereby forming a dispersion compensating element.
  • a plurality of optical paths can be formed in the same dispersion compensating element by appropriately selecting a combination of elements capable of performing the dispersion compensation according to the circumstances of the incident light using electric means or the like. .
  • the inventors of the present invention have shown that a matrix-like element plate on which elements capable of performing such dispersion compensation can be stably mass-produced by applying a semiconductor manufacturing technique and a multilayer film forming technique. Confirmed by experiment.
  • the insertion loss of the dispersion compensating element as a whole can be extremely reduced, and multi-channel dispersion compensation can be performed by the same dispersion compensating element.
  • a small-sized dispersion compensator having excellent dispersion compensation characteristics can be provided at low cost.
  • FIG.6D shows an optical dispersion compensating element 4440 in which elements 442 and 443 capable of performing the same dispersion compensation as in FIG.6A are incorporated in the same case 441.
  • the element 4 43 that can perform dispersion compensation uses a multilayer film in which the film thickness changes in the direction of the plane of incidence of the multilayer film described with reference to FIG. It has means for adjusting the incident position.
  • the incident position adjusting means can adjust the incident position by using a control circuit provided in a force case 441 (not shown).
  • optical dispersion compensating element Using the optical dispersion compensating element according to the present invention having such a configuration, dispersion is compensated in a communication system transmitting 60 km at a communication bit rate of 40 Gbps, and as a result, extremely excellent dispersion compensation can be performed.
  • Signal light is transmitted through the optical dispersion compensator.
  • the loss due to passing was as low as 1 dB or less. It can be said that this loss is much better than the loss due to a single second-order dispersion compensator using a conventional fiber grating, which is as large as 3 to 6 dB.
  • the light dispersion compensating element of the present invention and the light dispersion compensating method using the element have been described centering on the light dispersion compensating element of the present invention.
  • the most notable features of the light dispersion compensating method of the present invention are as follows.
  • the dispersion compensator is configured to have a group velocity delay time-wavelength characteristic curve that has at least one extreme value in any one wavelength range of 1675 nm, and is optimal for communication conditions It is also possible to compensate for the extreme values at multiple wavelengths in the wavelength range of 1260 to 1700 nm, for example, by using a function that can be selected with a switching switch as a whole as a dispersion compensation element.
  • the present invention makes use of such a large degree of freedom to make it possible to perform second- and third-order dispersion compensation required in actual communication, and makes use of many conventional optical communication systems. It enables high-speed and long-distance communication.
  • the present invention has been described in detail. According to the present invention, good dispersion compensation of each channel is performed by preparing various group velocity delay time-wavelength characteristic curves described with reference to FIGS. 5B to 5D. In addition to this, good dispersion compensation of multiple channels can be performed.
  • the dispersion compensation by the optical dispersion compensating element of the present invention has a particularly large effect in the third-order or higher dispersion compensation, and in addition to the second-order dispersion compensation by appropriately adjusting the group velocity delay time-wavelength characteristic. Can also be performed.
  • the present invention is indispensable for practical use of high-speed and long-distance optical communication such as transmitting 10,000 km at 4 OGb ps, has a wide use range, and greatly contributes to the development of the optical communication field. Things.
  • the light dispersion compensating element using the special multilayer film according to the present invention is compact and mass-produced. Since it is suitable and can be provided at a low price, it greatly contributes to the development of optical communication.
  • optical dispersion compensating element of the present invention makes it possible to use many of the existing optical communication systems, and has a great social and economic effect.

Landscapes

  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)

Abstract

L'invention concerne un dispositif de compensation de dispersion optique qui élimine une forte perturbation de la communication engendrée par la dispersion de longueurs d'onde rencontrée dans une émission de signaux par une fibre optique, dans une communication par fibres optiques présentant un débit binaire d'au moins 10 Gbit/s, en particulier d'au moins 40 Gbit/s. Ledit dispositif de compensation présente également une grande largeur de bande et une grande zone polaire pour une temporisation de la vitesse de groupe. Ce dispositif est obtenu par connexion en série d'une pluralité d'éléments à pellicule complexe, capables de compenser la dispersion à l'aide des caractéristiques de longueur d'onde de temporisation de vitesse de groupe et permet, après diverses sélections de connexion, d'appliquer une compensation de dispersion cubique à un signal optique présentant une bande de longueur d'onde de largeur comprise entre 1 260 et 1 700 nm.
PCT/JP2001/003769 2000-05-01 2001-05-01 Dispositif de compensation de dispersion optique et procede de compensation de dispersion optique utilisant ledit dispositif WO2001084750A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2001252667A AU2001252667A1 (en) 2000-05-01 2001-05-01 Optical dispersion compensating device and optical dispersion compensating method using the device

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP2000-132705 2000-05-01
JP2000132705 2000-05-01
JP2000-132707 2000-05-01
JP2000132706 2000-05-01
JP2000-132706 2000-05-01
JP2000132707 2000-05-01

Publications (1)

Publication Number Publication Date
WO2001084750A1 true WO2001084750A1 (fr) 2001-11-08

Family

ID=27343297

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2001/003769 WO2001084750A1 (fr) 2000-05-01 2001-05-01 Dispositif de compensation de dispersion optique et procede de compensation de dispersion optique utilisant ledit dispositif

Country Status (2)

Country Link
AU (1) AU2001252667A1 (fr)
WO (1) WO2001084750A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07327012A (ja) * 1994-05-25 1995-12-12 At & T Corp 光通信システム
JPH1041891A (ja) * 1996-04-02 1998-02-13 Corning Inc ファイバ伝送システム用切換え可能な光ファイバデバイスおよびそのコンポーネント
JP2754214B2 (ja) * 1988-07-12 1998-05-20 工業技術院長 光パルスの周波数チャープ補償が出来る誘電体多層膜
JPH11183748A (ja) * 1997-12-18 1999-07-09 Nippon Telegr & Teleph Corp <Ntt> 高次分散補償器
JPH11218628A (ja) * 1998-02-04 1999-08-10 Hitachi Ltd 光分散補償素子および該素子を用いた半導体レーザ装置ならびに光通信システム
JP2000028934A (ja) * 1998-07-10 2000-01-28 Nippon Telegr & Teleph Corp <Ntt> 分散可変光等化器

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2754214B2 (ja) * 1988-07-12 1998-05-20 工業技術院長 光パルスの周波数チャープ補償が出来る誘電体多層膜
JPH07327012A (ja) * 1994-05-25 1995-12-12 At & T Corp 光通信システム
JPH1041891A (ja) * 1996-04-02 1998-02-13 Corning Inc ファイバ伝送システム用切換え可能な光ファイバデバイスおよびそのコンポーネント
JPH11183748A (ja) * 1997-12-18 1999-07-09 Nippon Telegr & Teleph Corp <Ntt> 高次分散補償器
JPH11218628A (ja) * 1998-02-04 1999-08-10 Hitachi Ltd 光分散補償素子および該素子を用いた半導体レーザ装置ならびに光通信システム
JP2000028934A (ja) * 1998-07-10 2000-01-28 Nippon Telegr & Teleph Corp <Ntt> 分散可変光等化器

Also Published As

Publication number Publication date
AU2001252667A1 (en) 2001-11-12

Similar Documents

Publication Publication Date Title
WO2002023234A1 (fr) Dispositif de compensation de la dispersion optique, dispositif composite de compensation de la dispersion optique comportant ledit dispositif et procede de compensation de la dispersion optique a l&#39;aide de ce dispositif
US6943951B2 (en) Optical component and dispersion compensation method
JP2001320328A (ja) 光通信方法
US9229219B2 (en) Optical filter, optical filter module, spectrometric instrument, and optical instrument
JP2002267834A (ja) 光学部品およびその部品を用いた光分散補償器ならびに光分散補償方法
US8456741B2 (en) Optical module having three or more optically transparent layers
JP2000105313A (ja) 分散補償器
JP4613814B2 (ja) 可変分散補償器
WO2002031542A1 (fr) Element de correction de dispersion optique, element composite de correction de dispersion optique utilisant cet element, et procede de correction de dispersion optique utilisant cet element
WO2001084750A1 (fr) Dispositif de compensation de dispersion optique et procede de compensation de dispersion optique utilisant ledit dispositif
JP2002122732A (ja) 光分散補償素子
JP5218243B2 (ja) 光モジュール
WO2001084749A1 (fr) Dispositif de compensation de la dispersion optique, et procede de compensation de la dispersion optique utilisant ledit dispositif
JP2002214430A (ja) 光分散補償素子
WO2001086339A1 (fr) Element de compensation de la dispersion de la lumiere et procede de compensation de la dispersion de la lumiere a l&#39;aide dudit element
WO2001094991A1 (fr) Dispositif composite de compensation de dispersion de la lumiere et procede de compensation de dispersion de la lumiere l&#39;utilisant
JP2001305339A (ja) 光分散補償素子
JP2002071945A (ja) 光分散補償素子とその素子を用いた光分散補償方法
JP2001251246A (ja) 光分散補償素子
JP2001305338A (ja) 光分散補償素子
JP2001352293A (ja) 光分散補償素子とその素子を用いた光分散補償方法
JP2006221075A (ja) 可変分散補償器
JP2002208894A (ja) 光通信方法およびその方法を用いた光通信装置
US7062122B2 (en) Tunable optical add/drop device
JPH11326633A (ja) 波長選択素子およびこれを使用した光学装置

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG US UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 69(1) EPC

122 Ep: pct application non-entry in european phase