JP5901916B2 - Optical spectrum measurement device - Google Patents

Description

  The present invention relates to an optical fiber connection structure of an optical spectrum measuring apparatus.

  An optical spectrum measuring device is a measuring device that measures and analyzes the optical power corresponding to each wavelength by spectroscopy, such as measuring the emission wavelength and spectral width of a light emitting element, measuring the loss wavelength characteristics of an optical fiber, optical filter, etc. It is used for measuring attenuation characteristics, transmission characteristics, and cutoff wavelengths.

  In an optical spectrum measuring apparatus, light incident from an optical fiber connected to an optical connector is divided into narrow wavelength slots using an optical bandpass filter, and is replaced with an electrical signal by a photodiode. Then, the optical spectrum is obtained by plotting the electric signal obtained while sweeping the center wavelength of the optical bandpass filter. As the optical bandpass filter, a mechanical device using an optical prism called a monochromator (spectrometer) is used.

Japanese Patent Laid-Open No. 11-125562

  In recent years, with the spread of optical fiber networks represented by FTTH (Fiber To The Home) lines, the measurement targets of optical spectrum measurement devices are also the optical spectrum evaluation of optical transceivers, the gain evaluation of optical fiber amplifiers, Multiplexing), such as signal quality evaluation in transmission systems.

  Various types of optical fibers used for these measurements differ in diameter, multimode / single mode, core type, and the like. Different types of optical fibers cannot be connected to a common optical connector because they have different sizes and structures or have different wavelength characteristics. For this reason, conventionally, an optical spectrum measuring device corresponding to the type of optical fiber has to be prepared, which has been a heavy burden on the user.

  It is conceivable to connect different types of optical fibers to the optical switch and switch the optical switch to cope with different types of optical fiber. However, the optical switch is expensive and requires switching control. Further, since the optical switch itself has wavelength characteristics, it is not possible to switch between a multimode optical fiber and a single mode optical fiber by connecting them to one optical switch.

  Therefore, an object of the present invention is to provide an optical spectrum measuring apparatus that can perform measurement using a plurality of different types of optical fibers with a simple configuration.

  In order to solve the above problems, an optical spectrum measurement apparatus according to a first aspect of the present invention is an optical spectrum measurement apparatus that changes the center wavelength of an optical bandpass filter and measures the optical spectrum of light to be measured. A plurality of optical connectors corresponding to different types of optical fibers, a bundle optical fiber in which each optical fiber on the branch side is connected to the plurality of optical connectors, and a bundle side is connected to the optical input end of the optical bandpass filter. And.

  In order to solve the above problems, an optical spectrum measuring apparatus according to a second aspect of the present invention is an optical spectrum measuring apparatus for measuring an optical spectrum of light to be measured by a polychromator having light receiving elements arranged in an array. A plurality of optical connectors corresponding to different types of optical fibers, a bundle optical fiber in which each optical fiber on the branch side is connected to each of the plurality of optical connectors, and a bundle side is connected to the optical input end of the polychromator. It is characterized by comprising.

  In any aspect, the optical fiber constituting the bundle optical fiber can be a type of optical fiber corresponding to the optical connector to be connected.

  In addition, a detection unit that detects an optical connector to which an optical fiber that enters measurement light is connected, and a calibration process according to the type of optical fiber to which the detected optical connector corresponds. And a calibration unit for performing the above.

  According to the present invention, there is provided an optical spectrum measuring apparatus capable of performing measurement using a plurality of different types of optical fibers with a simple configuration.

It is a block diagram which shows the structure of the optical spectrum measuring device which concerns on this embodiment. It is a figure which shows the structure of a monochromator. It is a figure which shows the end surface example of a bundle optical fiber. It is a front view of an optical spectrum measuring device. It is a flowchart which shows operation | movement of an optical spectrum measuring device. It is a figure which shows the structure of a polychromator.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an optical spectrum measuring apparatus according to the present embodiment. As shown in the figure, the optical spectrum measuring apparatus 100 includes a monochromator 110, a control unit 120, an output / display unit 130, an operation receiving unit 140, an input optical connector unit 150, and a bundle optical fiber 160.

  The bundle optical fiber 160 is a branched type in which a plurality of independent optical fibers are bundled on one end side. Each optical fiber constituting the bundle optical fiber 160 is connected to a plurality of optical connectors included in the input optical connector unit 150 on the other end side branched.

  The plurality of optical connectors included in the input optical connector unit 150 have shapes that allow connection of different types of optical fibers. That is, it is possible to connect optical fibers having different diameters, multimode / single mode, and core types.

  The bundle optical fiber 160 is configured by using the same type of optical fiber as the type of optical fiber corresponding to each optical connector. Each optical fiber constituting the bundle optical fiber 160 is connected to an optical connector corresponding to the same type of optical fiber as the type of the optical fiber. For example, an optical connector that connects a large-diameter optical fiber, an optical connector that connects a large-diameter optical fiber among optical fibers constituting the bundle optical fiber 160, and an optical connector that connects a single-mode optical fiber, Of the optical fibers constituting the bundle optical fiber 160, a single mode optical fiber is connected.

  The input optical connector unit 150 is provided with a sensor 151 that detects which optical connector is connected to the optical fiber. The sensor 151 can be configured using, for example, a mechanical switch or an optical sensor.

  The monochromator 110 functions as an optical bandpass filter that divides input light into narrow wavelength slots. FIG. 2 is a diagram showing the configuration of the monochromator. As shown in the figure, the monochromator 110 includes two parabolic mirrors (a collimating mirror 111 and a focusing mirror 112), a diffraction grating (grating) 113, an exit slit 114, and a photodiode 115. ing.

  The diffraction grating 113 is an optical element in which a very fine groove is cut on a mirror and takes out light of a specific wavelength from light having various wavelengths. That is, when light mixed with various wavelengths is incident on the diffraction grating 113, diffraction occurs at an angle determined by each wavelength. Therefore, the wavelength can be specified based on the angle diffracted from the diffraction grating 113.

  In the monochromator 110, light incident from the bundle-side end surface 161 of the bundle optical fiber 160 is converted into parallel light by the collimating mirror 111 and guided to the diffraction grating 113. The light diffracted by the diffraction grating 113 forms an image of the spectrum in the dispersion direction around the exit slit 114 by the focusing mirror 112. Therefore, only light having a wavelength collected on the exit slit 114 in the spectrum is detected by the photodiode 115. The wavelength of light to be detected, that is, the center wavelength of the optical bandpass filter can be changed by rotating the diffraction grating 113.

  The bundle-side end surface 161 of the bundle optical fiber 160 may have a shape in which the optical fibers are bundled in a high-density annular shape as shown in FIG. 3A, or as shown in FIG. 3B. The optical fibers may be bundled in a line shape. By bundling in the shape of a line perpendicular to the rotation plane of the diffraction grating 113, the light to be measured input from each optical fiber can be measured with a relatively small wavelength error.

  Returning to the description of the block diagram of FIG. 1, the control unit 120 is a block that controls various operations in the optical spectrum measurement apparatus 100 and performs measurement, and includes a measurement control unit 121, a signal processing unit 122, and a calibration unit 123. ing.

  The measurement control unit 121 performs optical spectrum measurement control, including rotation control of the diffraction grating 113 of the monochromator 110. The signal processing unit 122 performs signal processing such as amplification and A / D conversion of the electrical signal detected by the photodiode 115 of the monochromator 110.

  The calibration unit 123 performs calibration processing according to the detection result of the sensor 151 that detects the optical connector to which the measurement optical fiber is connected. In general, calibration values often vary depending on the type of optical fiber to be connected. For example, when a multi-mode fiber is connected to an optical spectrum measuring apparatus calibrated assuming that a single-mode optical fiber is connected, the measurement accuracy may be reduced.

  Therefore, the calibration unit 123 acquires and stores calibration values for each type of optical fiber in advance. Then, the optical fiber used for the measurement is acquired from the sensor 151, the calibration value corresponding to the optical fiber is read, and the measurement value of the signal processing unit 122 is calibrated.

  The output / display unit 130 displays the measurement result of the control unit 120 on the display screen or outputs it as electronic data to the outside. The operation reception unit 140 includes a plurality of operation elements such as a rotary knob and a switch, and receives an operation from a user.

  Note that the bundle optical fiber 160 and the input optical connector unit 150 may be provided outside the casing of the optical spectrum measuring apparatus 100. At this time, the bundle optical fiber 160 and the input optical connector unit 150 may be replaceable so as to be compatible with more types of optical fibers. Moreover, you may make it provide the optical connector according to the wavelength band of the laser transmitted with an optical fiber.

  FIG. 4 is an example of a front view of the optical spectrum measuring apparatus 100 according to the present embodiment. As shown in this figure, on the front side of the optical spectrum measuring apparatus 100, in addition to the display screen of the output / display unit 130 and the operator of the operation receiving unit 140, a plurality of optical fibers for connecting a plurality of types of measurement optical fibers are connected. An input optical connector unit 150 having the optical connector is arranged. It is desirable to display the type of optical fiber corresponding to the optical connector in the vicinity of each optical connector of the input optical connector unit 150.

  FIG. 5 is a flowchart showing a measurement procedure of the optical spectrum measuring apparatus 100 according to the present embodiment. In measuring the optical spectrum, a measurement optical fiber connection is received from the user (S101). At this time, the user connects to an optical connector corresponding to the type of optical fiber used for measurement. Moreover, setting of measurement conditions, setting of analysis contents, and the like can be performed in the same manner as a conventional optical spectrum measuring apparatus.

  When the optical fiber is connected, the sensor 151 detects the optical connector to which the optical fiber is connected (S102). Then, the calibration unit 123 sets a calibration value corresponding to the detected optical connector (S103).

  Then, the optical spectrum is measured for the light incident from the measurement optical fiber (S104). At this time, calibration processing is performed using the calibration value set by the calibration unit 123. The measurement may be repeated a plurality of times to calculate the average value.

  When the measurement is completed, the measurement result, the analysis result, etc. are output from the output / display unit 130 (S105).

  As described above, the optical spectrum measuring apparatus 100 of the present embodiment uses the bundle optical fiber 160 in which the branch side is connected to the optical connector and the bundle side is connected to the monochromator 110. Measurement using a plurality of different types of optical fibers can be realized without increasing the cost.

  In the above embodiment, the example using the monochromator 110 that measures the optical spectrum by rotating the diffraction grating 113 has been described. However, in the present invention, the diffraction grating 113 is fixed and arranged in an array. A polychromator that performs optical spectrum measurement by receiving light with a photodiode may be used.

  FIG. 6 is a diagram showing the configuration of the polychromator. The same components as those of the monochromator 110 shown in FIG. As shown in the figure, the polychromator 170 includes two parabolic mirrors (a collimating mirror 111 and a focusing mirror 112), a diffraction grating (grating) 113, and photodiodes 116 arranged in an array. ing. In the polychromator 170, the diffraction grating 113 is fixed without rotating during spectrum measurement. For this reason, the rotation control at the time of spectrum measurement by the measurement control part 121 is unnecessary.

  In the polychromator 170, the light incident from the bundle-side end surface 161 of the bundle optical fiber 160 is converted into parallel rays by the collimating mirror 111 and guided to the diffraction grating 113. The light diffracted by the diffraction grating 113 forms a spectrum image at any position of the photodiode 116 arranged in an array by the focusing mirror 112. Since the image formation position depends on the diffraction angle in the diffraction grating 113, that is, the wavelength, the light spectrum can be obtained by measuring the received light intensity of each photodiode arranged in an array.

DESCRIPTION OF SYMBOLS 100 ... Optical spectrum measuring device 110 ... Monochromator 111 ... Collimating mirror 112 ... Focusing mirror 113 ... Diffraction grating 114 ... Output slit 115 ... Photodiode 116 ... Photodiode 120 arranged in array form ... Control part 121 ... Measurement control part 122 ... Signal processing unit 123 ... Calibration unit 130 ... Output / display unit 140 ... Operation receiving unit 150 ... Input optical connector unit 151 ... Sensor 160 ... Bundle optical fiber

Claims (3)

An optical spectrum measuring device that changes the center wavelength of the optical bandpass filter and measures the optical spectrum of the light to be measured,
A plurality of optical connectors for different types of optical fibers;
Each optical fiber on the branch side is connected to each of the plurality of optical connectors, and a bundle optical fiber in which the bundle side is connected to the optical input end of the optical bandpass filter;
With
An optical spectrum measuring apparatus, wherein the optical fiber constituting the bundle optical fiber is an optical fiber of a type corresponding to an optical connector to be connected. An optical spectrum measuring apparatus for measuring an optical spectrum of light to be measured by a polychromator having light receiving elements arranged in an array,
A plurality of optical connectors for different types of optical fibers;
Each optical fiber on the branch side is connected to each of the plurality of optical connectors, and a bundle optical fiber in which the bundle side is connected to the optical input end of the polychromator,
Equipped with a,
An optical spectrum measuring apparatus, wherein the optical fiber constituting the bundle optical fiber is an optical fiber of a type corresponding to an optical connector to be connected . Among the plurality of optical connectors, a detection unit that detects an optical connector to which an optical fiber that enters the light to be measured is connected;
A calibration unit that performs a calibration process according to the type of optical fiber corresponding to the detected optical connector;
The optical spectrum measuring apparatus according to claim 1 or 2, further comprising: