WO2006085650A1 - Dispositif de surveillance de longueur d’onde - Google Patents

Dispositif de surveillance de longueur d’onde Download PDF

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Publication number
WO2006085650A1
WO2006085650A1 PCT/JP2006/302467 JP2006302467W WO2006085650A1 WO 2006085650 A1 WO2006085650 A1 WO 2006085650A1 JP 2006302467 W JP2006302467 W JP 2006302467W WO 2006085650 A1 WO2006085650 A1 WO 2006085650A1
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WIPO (PCT)
Prior art keywords
wavelength
polarization
optical
diffraction grating
ray
Prior art date
Application number
PCT/JP2006/302467
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English (en)
Japanese (ja)
Inventor
Yoshihiro Konno
Masaru Sasaki
Original Assignee
Namiki Seimitsu Houseki Kabushiki Kaisha
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
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Application filed by Namiki Seimitsu Houseki Kabushiki Kaisha filed Critical Namiki Seimitsu Houseki Kabushiki Kaisha
Priority to JP2007502671A priority Critical patent/JPWO2006085650A1/ja
Publication of WO2006085650A1 publication Critical patent/WO2006085650A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G01J3/0205—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G01J3/0205—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
    • G01J3/0224—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows using polarising or depolarising elements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/28—Investigating the spectrum
    • G01J3/2803—Investigating the spectrum using photoelectric array detector
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J9/00—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength

Definitions

  • the present invention relates to a wavelength monitor device for measuring the wavelength of individual channels in a wavelength division multiplexing optical communication system.
  • TDM time division multiplex
  • WDM wavelength division multiplex
  • intervals the wavelength spacing and frequency spacing of individual channels in the WDM system
  • the wavelength of the light source of each channel may gradually deviate from the nominal center frequency force in the long term, and on the other hand, as the communication traffic increases as described above, the interval will be narrowed in the future. There is a tendency to go.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2003-140212 (page 3, FIG. 5)
  • the wavelength monitor device 100 of FIG. 10 receives a first lens 102, an AWG optical waveguide 103, and a second lens 104 when an optical signal of ⁇ 1 to 4 is input to one of the optical fibers 101 on the input side. Then, the optical signals of ⁇ 1, ⁇ 2, ⁇ 3, and ET4 are output separately from the plurality of optical fibers 105 on the output side, and the output optical signals are received by a light receiver (not shown) to be optical signals. It is configured to monitor the wavelength.
  • the optical signal is separated into two polarization components by a birefringent element, and the two polarization components are diffracted and condensed by a Littrow lens and a diffraction grating, respectively, and are completely collected.
  • a wavelength monitoring device that forms two spectral images in a separated state and detects the sum of the intensities of the two spectral images with a linear image sensor (see, for example, Patent Document 2).
  • Patent Document 2 Japanese Patent Application Laid-Open No. 2003-194627 (Page 1, Fig. 1)
  • the wavelength monitor device 106 of FIG. 11 includes an incident optical fiber 107, two birefringent elements (indicated as “Savart plate” in Patent Document 2) 108, a Littrow lens 109, a diffraction grating 110, and a linear image.
  • Sensor (noted as “one-dimensional array sensor” in Patent Document 2) 111.
  • the optical signal L1 from the incident optical fiber is separated into two polarization components L21 and L22 by the birefringent element 108, and the Littrow lens After collimating at 109 and entering the diffraction grating 110 to diffract the two diffracted light components L41 and L42, the light is again incident on the Littrow lens 109 and condensed to form two completely separated spectral images. Is received by the light receiving surface of the linear image sensor 111 to monitor the intensity of the optical signal L1 for each wavelength. Disclosure of the invention
  • the fabrication accuracy of the array structure is severe, and as the spacing becomes smaller, such as 50 GHz, as the WDM system becomes more dense in the future, the entire array Has the disadvantage of increasing the size.
  • the entire wavelength monitor device becomes expensive because the cost of the AWG optical waveguide is high.
  • the diffraction grating must be powered for each wavelength of the optical signal to optimize the angle of the grating plane for each wavelength, so that the diffracted light always enters the Littrow lens. This necessitates a separate drive mechanism for changing the angle of the grating plane, which increases the cost and the overall wavelength monitor device. Furthermore, the drive control of the diffraction grating must be performed for each wavelength, and the drive of the wavelength monitor device becomes complicated and complicated.
  • the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a wavelength monitor device that can achieve an increase in size and a low cost by simplifying the optical system. It is to be.
  • the invention according to claim 1 of the present invention includes a collimating lens, a birefringent element that separates an optical signal into two polarization components of an ordinary ray and an extraordinary ray whose polarization directions are orthogonal to each other, and a rotation of 90 degrees.
  • An Faraday rotator having an angle, a diffraction grating having a grating surface in which a plurality of grooves or projections are formed in parallel, and a linear image sensor, and the direction of formation of the grooves or projections is the compound direction.
  • the crystal axis of the birefringent element and the diffraction grating are positioned so that they are parallel to the direction of extraordinary ray separation inside the refracting element, and the optical signal from the WDM device is incident on the collimating lens and collimated.
  • the collimated optical signal is separated into the ordinary ray and the extraordinary ray by the birefringent element, and the birefringent element force only the polarization component emitted as the ordinary ray is rotated by the Faraday rotation.
  • the polarization direction of the two polarization components is rotated in the same direction by diffracting the polarization component in the same groove portion or convex portion.
  • the spectral images of the two diffracted light components after diffraction are completely
  • the wavelength monitoring device is characterized in that in a separated state, the light is received by one light receiving portion of the linear image and the sum of the intensity of the optical signals is output.
  • the polarization direction of the separated polarization component is adjusted to the same direction, and an optical signal is incident on the grating surface of the diffraction grating. It is possible to receive the spectral images of the two diffracted light components on the light receiving part of the linear image sensor at the same diffraction angle without changing the angle. Therefore, it becomes possible to receive two spectral images of the same order diffracted light component in one light receiving part of the linear image sensor, and two diffracted lights of the same frequency and same order in different light receiving parts of the linear image sensor. Since the spectral image of the component can be prevented from being received, the wavelength resolution of the wavelength monitor device can be improved.
  • the optical system of the wavelength monitor device is composed of a collimating lens, a birefringent element, a Faraday rotator, a diffraction grating, and a linear image sensor
  • the AWG is guided like a conventional wavelength monitor device.
  • An optical system can be formed without using expensive components such as a waveguide. Accordingly, the cost of the wavelength monitor device can be reduced.
  • the light receiving unit of the linear image sensor can receive light without having to drive the diffraction grating each time.
  • the two polarization components are always diffracted at a constant angle when diffracting in the diffraction grating. I can do it. Further, the two polarization components are diffracted by the same groove or convex portion. As described above, the optical path length difference between the two diffracted light components after diffraction can be made zero.
  • the polarization direction of the two polarization components is made parallel to the formation direction of the groove portion or the convex portion, thereby diffracting. Since the polarization component in the other direction can be prevented from entering the diffracted light component later as noise, the wavelength resolution of the wavelength monitor device can be improved.
  • FIG. 1 is a schematic perspective view schematically showing a wavelength monitor device according to a first embodiment of the present invention.
  • FIG. 2 is a schematic plan view of the wavelength monitor device of FIG. 1 as viewed in the direction of arrow a in FIG.
  • FIG. 3 A configuration diagram of a WDM apparatus in which the wavelength monitoring apparatus of FIGS. 1 and 2 is incorporated.
  • FIG.4 Optical signal viewed from z-axis direction in each cross section indicated by broken lines (a) to (c) in Fig.2.
  • FIG. 5 A diffraction grating and a linear image sensor constituting the wavelength monitoring device of the first embodiment.
  • the partial fragmentary perspective view which shows only a sensor.
  • FIG. 1 A first figure.
  • FIG. 7 is a schematic perspective view schematically showing a wavelength monitor device of a second embodiment.
  • FIG. 8 A diffraction grating and a linear image sensor constituting the wavelength monitoring device of the second embodiment.
  • the partial fragmentary perspective view which shows only a sensor.
  • FIG. 10 is a schematic diagram showing an example of a conventional wavelength monitoring device using an AWG waveguide.
  • FIG. 11 is a perspective view showing an example of another conventional wavelength monitor device.
  • FIG. 1 is a schematic perspective view schematically showing the wavelength monitor device of the first embodiment
  • FIG. 2 is a view of the wavelength monitor device of FIG. 1 when the planar force indicated by the arrow a in FIG. 1 is also seen
  • 3 is a schematic plan view
  • FIG. 3 is a block diagram schematically showing a WDM apparatus in which the wavelength monitoring apparatus of FIGS. 1 to 2 is incorporated.
  • FIGS. 4 (a) to (c) are respectively shown in FIG.
  • FIG. 5 is a diagram showing a polarization plane of an optical signal seen in the z-axis direction in each cross section shown by broken lines (a) to (c), and FIG.
  • FIG. 5 shows a diffraction grating constituting the wavelength monitor device of the first embodiment.
  • FIG. 6 is a schematic partial perspective view showing only the linear image sensor, and FIG. 6 is a state diagram schematically showing a light receiving state of two spectrum images received by the linear image sensor.
  • the two-dot chain line in FIGS. 1, 2, and 5 indicates the optical path, and the optical path portion drawn in a relatively thin line indicates that the optical component propagates through the components of the optical system.
  • the wavelength monitoring device 1 of the first embodiment includes one birefringent element 2, two Faraday rotators 3a and 3b, and a diffraction grating. 4.
  • a collimating lens 5 and a rear image sensor 6 are provided.
  • the WDM apparatus 7 includes a plurality of optical transmitters 8 including a light source (not shown) that transmits an optical signal, A multiplexer 9 that wavelength-multiplexes the optical signals of a plurality of channels transmitted from the optical transmitter 8 and an optical signal that is wavelength-multiplexed by the multiplexer 9 are connected in multiple stages to amplify and repeat the optical signal.
  • optical signals emitted from the light sources of the plurality of optical transmitters 8 having different wavelengths are multiplexed on the wavelength axis by the multiplexer 9, and the multiplexed optical signals are combined into a single optical fiber 13.
  • the optical signal multiplexed on the wavelength axis is separated for each wavelength by the demultiplexer 11 and received by the optical receiver 12.
  • An example of the branching ratio is 5:95. 95% of the light is guided to the optical fiber 13 and sent to the receiving side, and 5% of the optical signal is guided to the wavelength monitoring device 1 via the optical fiber 14.
  • the optical fiber 15 is a single mode optical fiber, for example, and the core has a diameter of 10 ⁇ m, for example.
  • Optical fiber 15 force When an optical signal si is incident, the optical signal si is separated into two polarization components of an ordinary ray s2 and an extraordinary ray s3 whose polarization directions are orthogonal to each other by the birefringent element 2 (hereinafter referred to as necessary) According to, s2 is described as “optical signal” or “ordinary ray”, and s3 is described as “optical signal” or “abnormal ray”).
  • the polarization plane of the optical signal si is shown in Fig. 4 (a).
  • the birefringent element 2 is composed of a birefringent crystal such as rutile, and the crystal axis XI direction on the optical surface 2a is set to 0 degrees so as to be parallel to the X-axis direction, which is the horizontal direction, and has a thickness.
  • the direction of crystal axis X2 in the direction is set so as to exhibit an angle of 45 degrees from optical surface 2a.
  • the thickness of the birefringent element 2 is set so that the incident optical signal si is completely separated into the ordinary ray s2 and the extraordinary ray s3.
  • the birefringent element 2 configured in this manner is arranged immediately after the collimating lens 5 and separates the collimated optical signal si incident on the collimating lens 5 into two polarization components s2 and s3.
  • the ordinary ray s2 goes straight in the z-axis direction inside the birefringent element 2, and the extraordinary ray s3 is not in the z-axis direction.
  • the light is refracted and propagated in the oblique direction that forms an angle ⁇ and in a direction parallel to the X-axis direction.
  • the birefringent element is separated into two polarization components s2 and s3. Only the polarization component s2 emitted from 2 and emitted as an ordinary ray is transmitted through the Faraday rotators 3a and 3b arranged in the subsequent stage.
  • the two Faraday rotators 3a and 3b each have a rotation angle of 45 degrees, and the rotation direction is set to be the same when viewed from the propagation direction of the polarization component s2. Therefore, the Faraday rotators 3a and 3b have a rotation angle of 90 degrees in total.
  • the Faraday rotators 3a and 3b are magnetically saturated by magnets M arranged adjacent to each other (not shown in FIG. 1).
  • the polarization direction of the polarization component s3 are set in the same direction, and the polarization directions of the two polarization components s2 and s3 are the same direction.
  • the optical signal is further arranged at the subsequent stage and is incident on the grating surface of the diffraction grating 4 that is V.
  • the diffraction grating 4 is a reflection type diffraction grating, and its grating surface is elongated in the X-axis direction as shown in FIG. 5 and has a plurality of groove portions 4a formed in one dimension in parallel to each other. is there.
  • the separation direction of the extraordinary ray s3 in the birefringence element 2 and the diffraction grating 4 It can be seen that the directions of the crystal axes XI and X2 and the position of the diffraction grating 4 are determined so that the formation direction (X-axis direction) of each of the grooves 4a is parallel to the same direction.
  • the two polarized light components s2 and s3 incident on the grating surface are reflected and diffracted by the grating surface and converted into two diffracted light components s21 and s31.
  • the polarization directions of the two polarization components s2 and s3 incident on the diffraction grating 4 are the same regardless of the polarization state of the optical signal si emitted from the optical fiber 15 as described above. Can be made. That is, even if the polarization state of the optical signal si changes, it is possible to keep the polarization directions of the two polarization components s2 and s3 in the same direction.
  • the two polarization components s2 and s3 incident on the diffraction grating 4 are always diffracted at a constant reflection angle when they are diffracted in the diffraction grating 4, so that the two diffracted light components after diffraction s21
  • the optical path length difference between s31 can be made zero.
  • the light enters the groove 4a.
  • the polarization directions of the polarization components s2 and s3 are parallel to the formation direction of the groove 4a. Accordingly, it is possible to prevent the polarized light component in the other direction from entering the diffracted light components s21 and s31 after diffraction as noise, so that the wavelength resolution of the wavelength monitor device 1 can be improved.
  • the polarization components s2 and s3 are the same groove portion (for example, the groove portions with diagonal lines in the examples of FIGS. 1 and 5) 4a
  • the optical path length difference between the two diffracted light components s21 and s31 after diffraction can be made zero.
  • the intensity ratio of the two diffracted light components s21 and s31 after diffracting the diffraction grating 4 is equal to the intensity ratio of the two polarized components s2 and s3 before the diffraction grating 4 is incident.
  • the two diffracted light components s21 and s31 diffracted from the diffraction grating 4 are propagated toward the linear image sensor 6 as shown in FIG.
  • Spectral images spl and sp2 from s21 and s31 are received in a completely separated state.
  • the completely separated state is a state in which there is no overlapping portion between the two spectral images spl and sp2.
  • the linear image 6 is omitted.
  • FIGS. 1 to 6 illustrate spot-like spectral images spl and sp2, assuming that the optical signal si propagated through the optical fiber 15 is monochromatic light (light having an arbitrary single wavelength). did. If the optical signal s1 is not monochromatic light, for example, if it contains two types of light with different wavelengths, the two spectral images spl and sp2 are spread along the wavelength dispersion direction (z-axis direction) on the light-receiving surface. The Furthermore, when an optical signal si containing various types of wavelengths is incident, a large number of spot-like spectral images are discretely arranged along the wavelength dispersion direction. The wavelength dispersion direction is orthogonal to the separation direction (X-axis direction) of the two spectral images spl and sp2.
  • the separation distance D1 (see FIG. 6) between the centers of the two spectral images spl and sp2 is proportional to the thickness of the birefringent element 2.
  • the two spectral images spl and sp2 are completely separated, and only one polarization component s2 can be transmitted to the Faraday rotators 3a and 3b. It is necessary to set the thickness of the birefringent element 2 so that the separation distance is obtained.
  • the linear image sensor 6 is elongated in the X-axis direction, which is the separation direction of the spectral images spl and sp2, on the light receiving surface, and has a large number of light receiving parts 6a. Light-receiving elements arranged one-dimensionally along the direction. Each of the light receiving portions 6a has an elongated strip shape.
  • the size of each light receiving unit 6a in the separation direction (X-axis direction) is set to a size capable of simultaneously receiving two spectral images spl and s p2, for example, separation of two spectral images spl and sp2. It is set to be larger than the sum of the distance D1 and the size D2 of each spectrum image spl, sp2 in the X-axis direction.
  • each light receiving portion 6a in the separation direction can also be set smaller than the sum of the separation distance D1 and the size D2 of the spectral images spl and sp2.
  • the linear image sensor 6 is arranged so that the center of the separation distance D1 is aligned with the center of each light receiving unit 6a, the spectral images spl and sp2 will be partially vignetted. Each amount of vignetting can be made equal.
  • each light receiving unit 6a in the z-axis direction is set according to the wavelength resolution necessary for measuring the spectral images spl and sp2. Further, the number of the light receiving parts 6a is set so that the wavelength range can be received without omission according to the wavelength range necessary for the measurement of the spectral images spl and sp2. As the linear image sensor 6, it is preferable to use one having uniform light receiving sensitivity of each light receiving section 6a (or one having the same light receiving sensitivity at the light receiving positions of at least two spectrum images spl and sp2).
  • the linear image sensor 6 receives the two spectral images spl and sp2 at the same time, if there is an overlapping part between the two spectral images spl and sp2, interference occurs in the overlapping part, and the overlapping part Thus, a polarization state similar to the original polarization state of the optical signal si appears. That is, the polarization state at the overlapping portion changes according to the polarization state of the incident optical signal si. For this reason, when the light receiving sensitivity of the linear image sensor 6 has some polarization dependence, the output of the linear image sensor 6 changes according to the polarization state in the overlapping portion of the spectral images spl and sp2. . Further, the output of the linear image sensor 6 also changes when the image intensity at the overlapping portion changes as a result of interference.
  • the two spectral images spl and sp2 are received by the linear image sensor 6 in a state of being completely separated.
  • the linear image sensor 6 can always output the sum of the intensities of the two spectral images spl and sp2.
  • the intensity for each wavelength of the optical signal emitted from the optical transmitter 8 It is possible to monitor the characteristics (intensity sum).
  • the intensity of the optical signal emitted from the optical transmitter 8 can be kept constant for each wavelength, and stable optical communication can be performed. It becomes possible.
  • the wavelength monitor device 1 of the present embodiment adjusts the polarization direction of the separated polarization components to the same direction, and then causes the optical signal to enter the grating surface of the diffraction grating 4, so that each polarization component is It is possible to receive the spectral images of the two diffracted light components at the light receiving part of the linear image sensor at the same diffraction angle without changing the diffraction angle. Accordingly, it is possible to receive two diffracted light component spectral images of the same order on one light receiving portion of the linear image sensor, and two diffracted light component spectral images of the same order at the same frequency on different light receiving portions. Since it is possible to prevent light from being received, the wavelength resolution of the wavelength monitoring device 1 can be improved.
  • the optical system of the wavelength monitor device 1 is composed of the collimating lens 5, the birefringent element 2, the Faraday rotators 3a and 3b, the diffraction grating 4, and the linear image sensor 6, the conventional wavelength monitor Like an apparatus, an optical system can be formed without using expensive components such as an AWG waveguide. Therefore, the cost of the wavelength monitor device 1 can be reduced.
  • the light receiving unit of the linear image sensor 6 can receive light without driving the diffraction grating 4 each time. It is possible to achieve downsizing and cost reduction by reducing the number of parts of the device 1 and facilitating the drive control of the wavelength monitor device 1.
  • FIG. 7 is a schematic perspective view schematically showing the wavelength monitor device of the second embodiment
  • FIG. 8 is a schematic view showing only the diffraction grating and the linear image sensor constituting the wavelength monitor device of the second embodiment
  • FIG. 9 is a partial perspective view
  • FIG. 9 is a schematic partial side view of the diffraction grating and the linear image sensor when FIG. 8 is viewed from the direction of arrow b.
  • the same parts as those in the first embodiment are denoted by the same reference numerals, and redundant descriptions are omitted or simplified.
  • the double-dashed line in FIGS. 7, 8, and 9 indicates the optical path, and the optical path portion drawn by a relatively thin line indicates that it propagates through the components of the optical system.
  • the wavelength monitor device 16 of the second embodiment is different from the wavelength monitor device 1 of the first embodiment in that a transmission type diffraction grating 17 is used.
  • a transmission type diffraction grating 17 is used on the lattice plane, as shown in FIG. 9, a large number of convex portions 17a in a rectangular wave shape are formed in a one-dimensional shape elongated in the X-axis direction and parallel to each other.
  • the separation direction of the extraordinary ray s3 inside the birefringent element 2 and the diffraction grating 17 The directions of the crystal axes XI and X2 and the position of the diffraction grating 17 are determined so that the formation direction (X-axis direction) of each of the convex portions 17a is parallel to the same direction.
  • the two polarized components s2 and s3 incident on the grating surface are transmitted through the grating surface and diffracted by the convex portion 17a, and converted into two diffracted light components s21 and s31 as shown in FIG. In FIGS. 7 to 9, only the 0th-order diffracted light component is shown for simplicity.
  • the polarization directions of the two polarization components s2 and s3 incident on the diffraction grating 17 are made the same regardless of the polarization state of the optical signal si emitted from the optical fiber 15. I can do it. That is, even if the polarization state of the optical signal si changes, it is possible to keep the polarization directions of the two polarization components s2 and s3 in the same direction. For this reason, when the two polarization components s2 and s3 incident on the diffraction grating 17 are diffracted by the diffraction grating 17, the diffracted light components of the same order are always diffracted in the same direction.
  • the polarization directions of the polarization components s2 and s3 are parallel to the direction in which the convex portion 17a is formed. Accordingly, it is possible to prevent the polarization component in the other direction from entering the diffracted light components s21 and s31 after diffraction as noise, so that the wavelength resolution of the wavelength monitor device 16 can be improved.
  • the two diffracted light components s21 and s31 after diffraction are diffracted by diffracting the polarization components s2 and s3 by the same convex portion 17a in a state where the polarization directions of the two polarization components s2 and s3 are the same direction.
  • the intensity ratio of the two diffraction light components s21 and s31 after diffracting the diffraction grating 17 is equal to the intensity ratio of the two polarization components s2 and s3 before the diffraction grating 17 is incident.
  • the two diffracted light components s21 and s31 diffracted from the diffraction grating 17 are propagated toward the linear image sensor 6 as shown in FIG.
  • Spectral images spl and sp2 from s21 and s31 are received in a completely separated state.
  • FIGS. 7 to 9 illustrate spot-like spectral images spl and sp2, assuming that the optical signal si propagated through the optical fiber 15 is monochromatic light (light having an arbitrary single wavelength). did.
  • the two spectral images spl and sp2 are received by the linear image sensor 6 in a completely separated state. As a result, the linear image sensor 6 can always output the sum of the intensities of the two spectral images spl and sp2.
  • the WDM apparatus 7 shown in FIG. 3 it is possible to monitor the intensity characteristic (intensity sum) for each wavelength of the optical signal emitted from the optical transmitter 8.
  • the intensity of the optical signal emitted from the optical transmitter 8 can be kept constant for each wavelength, and stable optical communication is possible. Is possible
  • the wavelength monitor device 16 of the present embodiment adjusts the polarization direction of the separated polarization components to the same direction, and makes the optical signal incident on the grating surface of the diffraction grating 17. It is possible to receive the spectral images of the two diffracted light components at the light receiving part of the linear image sensor at the same diffraction angle without changing the diffraction angle every time. Therefore, it becomes possible to receive two spectral images of the same order of diffracted light components on one light receiving portion of the linear image sensor, and spectral images of two diffracted light components of the same order at the same frequency on different light receiving portions. As a result, the wavelength resolution of the wavelength monitor 16 can be improved.
  • the optical system of the wavelength monitor device 16 is also composed of a collimating lens 5, a birefringent element 2, a Faraday rotator 3a, 3b, a diffraction grating 4, and a linear image sensor 6. Unlike a long monitor device, an optical system can be formed without using expensive components such as an AWG waveguide. Therefore, the cost of the wavelength monitor device 16 can be reduced.
  • the light receiving section of the linear image sensor 6 can receive light without driving the diffraction grating 17 each time. It becomes possible to achieve downsizing and cost reduction by reducing the number of parts of the device 16 and facilitating drive control of the wavelength monitor device 16.
  • the shape of the convex portion formed on the grating surface of the transmission type diffraction grating 17 is the above-described rectangular wave shape.
  • it may be formed on a triangular wave-shaped convex portion.
  • the wavelength monitoring device of the present invention can be used not only as a monitoring device for intensity characteristics (intensity sum) for each wavelength of individual channels of a WDM device, but also as an optical spectrum analyzer or spectroscope. is there.

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Abstract

L’invention concerne un dispositif de surveillance de longueur d’onde, évitant toute augmentation de format et permettant de réduire les coûts en simplifiant un système optique. Le dispositif de surveillance de longueur d’onde comprend une lentille de collimation, un double élément de réfraction, un rotor de Faraday, un réseau de diffraction englobant une face de grille ayant une pluralité de gorges ou crêtes formées en parallèle et un capteur d’image linéaire. L’axe cristallin du double élément de réfraction et le réseau de diffraction sont positionnés pour que la direction pour former les gorges ou les crêtes soit parallèle à la direction de séparation d’un rayon anormal dans le double élément de réfraction. De plus, un signal optique provenant d’un dispositif WDM est collimaté par la lentille de collimation et il est séparé en un rayon normal et un rayon anormal par le double élément de réfraction. Seul le rayon normal passe à travers le rotor de Faraday, et la direction de polarisation tourne de 90 degrés pour disposer le rayon normal et le rayon anormal dans une direction de polarisation et pour diffracter ces éléments sur les gorges ou les crêtes. Dans le même temps, l’image spectrale des deux composantes de rayon de diffraction alors diffractées est reçue sur une portion réceptrice de lumière du capteur d’image linéaire pour ainsi générer la somme d’intensité des signaux optiques.
PCT/JP2006/302467 2005-02-14 2006-02-13 Dispositif de surveillance de longueur d’onde WO2006085650A1 (fr)

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JP2005-035399 2005-02-14
JP2005035399 2005-02-14

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012222747A (ja) * 2011-04-13 2012-11-12 Fujitsu Ltd 光チャンネルモニタおよび光伝送装置
CN106154424A (zh) * 2016-09-23 2016-11-23 山东科技大学 一种双端口法拉第旋转镜及环形器

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JP2003083810A (ja) * 2001-09-14 2003-03-19 Anritsu Corp 分光装置および光測定装置
JP2003194627A (ja) * 2001-12-28 2003-07-09 Nikon Corp 分光器
WO2003058183A1 (fr) * 2001-12-27 2003-07-17 Capella Photonics, Inc. Controleurs de puissance spectrale optique utilisant des schemas de detection a multiplexage temporel

Patent Citations (3)

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Publication number Priority date Publication date Assignee Title
JP2003083810A (ja) * 2001-09-14 2003-03-19 Anritsu Corp 分光装置および光測定装置
WO2003058183A1 (fr) * 2001-12-27 2003-07-17 Capella Photonics, Inc. Controleurs de puissance spectrale optique utilisant des schemas de detection a multiplexage temporel
JP2003194627A (ja) * 2001-12-28 2003-07-09 Nikon Corp 分光器

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012222747A (ja) * 2011-04-13 2012-11-12 Fujitsu Ltd 光チャンネルモニタおよび光伝送装置
CN106154424A (zh) * 2016-09-23 2016-11-23 山东科技大学 一种双端口法拉第旋转镜及环形器
CN106154424B (zh) * 2016-09-23 2019-02-22 山东科技大学 一种双端口法拉第旋转镜及环形器

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