WO2018016759A1 - Device for measuring optical wavelength - Google Patents

Abstract

The present invention relates to a device for measuring an optical wavelength and, more particularly, to a device for measuring an optical wavelength transmitted through an optical line of an optical communication network in which a plurality of optical wavelengths are muxed by a wavelength division multiplexing method. The disclosed device for measuring an optical wavelength may comprise: an optical input unit for receiving an optical signal including a plurality of optical wavelengths and outputting the optical signal as parallel light by means of a lens; a channel filter for filtering the optical signal outputted from the optical input unit; a rotating plate attached to the channel filter; a motor for rotating the rotating plate; a photodetector for converting the optical signal having passed through the channel filter into an electric signal and outputting the electric signal; a control unit for controlling a rotation angle of the motor; a signal processing unit for generating a rotation angle control signal for the control unit and extracting a light wavelength value on the basis of the rotation angle and the electric signal; and a display unit for displaying an optical wavelength value extracted from the signal processing circuit unit. According to the present invention, it is possible to check the quality and reliability of an optical communication system and facilitate the maintenance process of the optical communication network by providing accurate information on the wavelength value of the optical signal in a wavelength multiplexed optical communication system since it is possible to precisely measure the wavelength of the received optical signal and measure the output of the optical signal.

Description

Light wavelength meter

The present invention relates to an optical wavelength measuring apparatus, and more particularly, to an apparatus for measuring an optical wavelength transmitted in an optical path of an optical communication network in which a plurality of optical wavelengths are muxed by a wavelength division multiplexing method.

The wavelength division multiplex optical communication is a method of transmitting a plurality of optical wavelength signals simultaneously to one strand of optical fiber, so it is a technology that can transmit a lot of data while using an existing optical cable without additional expansion of the optical cable. Because of the more economical method than the time division method, the wavelength division multiplexing method is applied to most optical communication networks.

Wavelength division multiplexing can be classified into two types. Coarse Wavelength Division Multiplexing (hereinafter referred to as CWDM) can transmit optical signals of up to 18 channels by dividing the wavelength at 20nm intervals in the band range from 1270nm to 1610nm. Dense Wavelength Division Multiplexing (hereinafter referred to as DWDM) may transmit 80 channel signals by dividing the C band from 1530 nm to 1565 nm at 100 GHz (approximately 0.8 nm) or 50 GHz (approximately 0.4 nm). In addition to the C-band, DWDM supports O-bands (1260-1360 nm, 100 nm), E-bands (1360-1460 nm, bandwidth 100 nm), S-bands (1460-1530 nm, bandwidth 70 nm), and L-bands (1565-1). It can be used in various wavelength bands such as 1625 nm, 60 nm bandwidth) and U-band (1625 ~ 1675 nm, 50 nm bandwidth). Thus, wavelength division is a very effective communication method for increasing data transmission capacity.

Although wavelength division multiplexing has the advantage of economical transmission of large amounts of data, since multiple optical signals share one optical fiber, if the wavelength of an optical transmitter laser applied to wavelength division multiplexing is outside the allowable range of the allocated channel, It may cause data transmission error. Therefore, in order to install, maintain, and repair the wavelength division multiplexing, it is essential to measure the wavelength of the optical signal as well as the intensity (light output) of the optical signal.

In particular, CWDM optical transmitters, which are cheaper than expensive DWDM optical transmitters, are not equipped with a sensing element that measures the wavelength of the laser or a device capable of compensating for wavelength displacement. The wavelength of the optical signal can be changed. Therefore, the information about the exact wavelength of the optical signal transmitted in the channel currently in operation is very important to secure the reliability of the communication network.

An optical spectrum analyzer (OSA) may be used to obtain wavelength information of a transmitted optical signal. The optical spectrum analyzer has a wavelength resolution of 0.02 nm, which enables highly accurate measurement but is bulky, heavy, and expensive. There is this. As a result, optical spectrum analyzers are not suitable for use outdoors when performing fiber laying / maintenance / maintenance work.

Conventional wavelength measurement technologies for portable CWDM optical communication networks include Patents 10-1089182 and Patents 10-0820947, but such optical wavelength power meters measure optical power when the optical wavelength of the optical transmitter is within a predetermined wavelength channel band. This is possible but has the problem of not distinguishing whether the optical wavelength is at the center or the edge of the channel band.

  1 is a configuration diagram of an optical unit of an optical wavelength power meter shown in Patent 10-0820947.

  Referring to FIG. 1, an optical signal including a plurality of channels passes through a collimator lens 20 and a channel filter 31 to be incident on the photodetector 40, and a stepping motor 33 is a channel filter 31. While rotating the rotating plate 32 is attached to measure the light intensity for each channel of the optical signal including a plurality of channels. This method can measure the optical intensity of each channel when the input optical signal is within the range of the channel, but cannot distinguish whether the wavelength of the input optical signal is at the center of the channel or at the edge of the channel. The disadvantage is that it does not provide accurate information.

  2 is a diagram illustrating the channel configuration and the characteristics of the channel filter of the CWDM band.

As shown in FIG. 2, the CWDM has a center wavelength separated by 20 nm from 1270 nm to 1610 nm, and each channel band may have 20 nm. The channel filter 31 may pass a 7 nm band (for example, a 1483 nm to 1497 nm band when the center frequency is 1490 nm) on both sides of the center wavelength. The above-described disadvantages of the prior art will be further described with reference to FIG. 2, and the interval between CWDM channels is 20 nm as the interval dλ _ch between the center wavelengths λc of neighboring channels. When the bandwidth of each channel filter is λc ± 7nm, there may be a channel gap between the channel and the channel, and a total of 3 nm and 6 nm of left and right channels exist between the channels, respectively. 2. Description of the Related Art [0002] Conventional portable optical power meter measures 1491nm (22) or 1496nm in the two optical wavelengths 22 or 23 of FIG. Even if the value is 23, all of them are within the channel bandwidth, so only the light output for confirming that the optical signal is transmitted to the corresponding channel can be measured, and it is not known how far the optical wavelength is from the center wavelength. That is, the conventional portable optical wavelength power meter has a problem in that it is not possible to distinguish between the optical wavelength 22 and the optical wavelength 23, so that the exact wavelength value cannot be specified.

An object of the present invention to solve the above-mentioned problems is not only to measure the optical intensity of each channel in wavelength multiplexed optical communication, but also to measure how far the optical signal of each channel is from the center wavelength of the channel and even It is to provide a measuring instrument that can measure the light wavelength and light intensity even if it is out of range.

The optical wavelength measuring device according to the present invention for achieving the above object is an optical input unit for inputting an optical signal including a plurality of optical wavelengths and converting the optical signal into parallel light using a lens, the optical signal output from the optical input unit A channel filter for filtering, a rotating plate to which the channel filter is attached,

A motor for rotating the rotating plate, a photo detector for converting an optical signal passing through the channel filter into an electrical signal, and outputting the electric signal, a controller for controlling the rotation angle of the motor, and generating a rotation angle control signal for the controller, and the rotation A signal processor may extract an optical wavelength value based on an angle and the electrical signal, and a display unit may display an optical wavelength value extracted by the signal processing circuit. The electrical signal may be an analog signal proportional to the intensity of the optical signal passing through the channel filter, and the signal processor may extract the intensity of the optical signal based on the electrical signal.

The channel filter may be attached in parallel with a tangent in the rotation direction of the rotating plate so that an angle at which the optical signal is incident on the channel filter may change according to the rotation of the motor.

In addition, the signal processor may be configured to display the optical signal based on a rotation angle of the motor at a point where the electrical signal changes from a high point higher than a preset reference value to a low point that is smaller than the preset reference value or the electric signal changes from a low point to a high point. It is possible to extract the optical wavelength value contained in, calculate the displacement of the transmission band of the channel filter according to the rotation angle of the motor, and extract the optical wavelength value included in the optical signal based on the displacement. When calculating the displacement of the transmission band of the channel filter, it may be calculated based on the right edge wavelength or the left edge wavelength of the transmission band.

In order to enable the photodetector to receive the optical signal emitted from the optical input unit through a channel filter, the optical input unit, the channel filter, and the photo detector are a straight line parallel to a straight line connecting the center and the circumference of the rotating plate. The channel filter may be disposed on and between the light input unit and the photo detector.

The optical signal output from the optical input unit may be input to the center of the channel filter, may be input off the center of the channel filter, or may be input off the center of the channel filter, and may be input at an angle to the normal of the channel filter. Can be.

In addition, in order that the wavelength range that can be measured by the channel filter is greater than the bandwidth of the channel filter, the bandwidth of the channel filter may be narrower from the channel center wavelength to the shorter wavelength and wider to the longer wavelength at the incident angle of 0 degrees.

In addition, the optical wavelength measuring device receives a light source generator capable of generating a light source for calibration, a driver for driving the light source generator, and light output from the light source generator, and transmits light having a specific narrow band wavelength among inputs having a wide wavelength line width. And an in-line 50G DWDM filter for reflecting the other optical signals of the remaining wavelengths, wherein the optical input unit has two input ports, and the first input port receives an external optical signal for measurement. 2 The input port may receive a calibration optical signal through which the optical signal generated by the light source generator passes through the in-line 50G DWDM filter.

A plurality of channel filters may be attached to the rotating plate to make an optical wavelength measuring instrument having various channel characteristics, and the plurality of channel filters may be classified into one or more groups, and channel filters belonging to the same group may have the same bandwidth. It is composed of a filter having a transmission band between the channel filters belonging to different groups may be different. In more detail, the plurality of channel filters may be classified into one group, and may include a plurality of 50G DWDM channel filters or a plurality of 100G DWDM channel filters.

The plurality of channel filters are classified into two groups, the first group is composed of a plurality of CWDM channel filters and the second group is composed of a plurality of DWDM channel filters, or the first group is a plurality of 50G DWDM. Channel filters for the second group and the second group is composed of a plurality of channel filters for 100G DWDM, or the first group is composed of a plurality of channel filters for C-band DWDM and the second group is a plurality of L-band DWDM The channel filters may be configured.

In contrast, the transmission bands according to the wavelength bands proposed by E-PON, G-PON, GE-PON, 10G-PON, and NG-PON2, which are communication standards of the optical subscriber network, in which the configuration of the plurality of channel filters is standardized. And a CWDM channel filter having a CWDM channel filter, a broadband filter, and a DWDM channel filter having transmission bands of 200 GHz, 100 GHz, 50 GHz, and 50 GHz or less.

According to the present invention, it is possible to precisely measure the wavelength of the received optical signal and to measure the output of the optical signal, thereby providing accurate information on the wavelength value of the optical signal in the wavelength multiplex optical communication system. It can be checked and it can facilitate the maintenance and repair of the optical network.

1 is a configuration diagram of an optical unit of an optical wavelength power meter shown in Patent 10-0820947.

2 is a diagram illustrating the channel configuration and the characteristics of the channel filter of the CWDM band.

3 is a diagram illustrating a change in wavelength to be filtered according to a change in incident angle.

4 is a diagram illustrating a configuration of an optical wavelength meter according to an exemplary embodiment of the present invention.

5 is a view showing the structure of the optical unit of the optical wavelength meter according to another embodiment of the present invention.

6 is a view showing the structure of the optical unit of the optical wavelength meter according to another embodiment of the present invention.

FIG. 7 illustrates that the optical signal 414 enters the center of the channel filter 422 at the incident angle of 0 degrees when the wavelength is measured while rotating one channel filter, without causing loss of the optical signal 414. FIG. 2 is a diagram for calculating rotation angles 720 and 721 capable of rotating the channel filter 422 as much as possible.

FIG. 8 illustrates that when the wavelength is measured while rotating one channel filter, when the optical signal 414 is incident from the center of the channel filter 422 at the incident angle of 0 degrees, the optical signal 414 is not generated. 3 is a diagram for calculating a rotation angle 820 that can rotate the channel filter 422 as much as possible.

FIG. 9 is another embodiment of the present invention for varying the angle of incidence, in which a beam of light signal 414 incident on channel filter 422 is made to make the maximum angle of incidence larger so that a larger wavelength shift occurs than in the method of FIG. It is a figure which shows the method of inclining itself and injecting into a filter.

FIG. 10 is a diagram illustrating an example in which a transmission band wavelength of the channel filter 422 is changed by changing the incident angle φ according to the rotation angle θ of the motor when the motor 425 is rotated.

FIG. 11 is a diagram for describing a method of measuring a wavelength of an input optical signal according to an exemplary embodiment.

12 is a view for explaining a method of measuring a wavelength of an input optical signal according to another embodiment of the present invention.

FIG. 13 is a diagram showing an embodiment in which 100 GHz DWDM is applied to a C-band (1530 to 1565 nm, bandwidth 35 nm) wavelength band.

FIG. 14 is a graph showing a relationship between an incident angle and a wavelength displacement of a DWDM filter having λ _o = 1570 nm and n _eff = 1.5764.

FIG. 15 is a diagram illustrating a configuration of an optical wavelength measuring device optical part for 100 GHz DWDM C-band according to an embodiment of the present invention.

FIG. 16 is a view showing the configuration of an optical wavelength measuring instrument optical unit for a 100 GHz DWDM C-band having a light source for wavelength calibration according to another embodiment of the present invention.

FIG. 17 illustrates an embodiment of generating a calibration optical signal 413a.

FIG. 18 is a diagram illustrating a wavelength band defined in a communication standard (E-PON, G-PON, GE-PON, 10G-PON, NG-PON2) of the optical subscriber network that is currently standardized.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and like reference numerals designate like elements throughout the specification.

  Throughout the specification, when a part is "connected" to another part, this includes not only "directly connected" but also "electrically connected" with another element in between. . In addition, when a part is said to "include" a certain component, this means that it may further include other components, except to exclude other components unless otherwise stated.

  When a portion is referred to as being "above" another portion, it may be just above the other portion or may be accompanied by another portion in between. In contrast, when a part is mentioned as "directly above" another part, no other part is involved between them.

  Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited to these. These terms are only used to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, the first portion, component, region, layer or section described below may be referred to as the second portion, component, region, layer or section without departing from the scope of the invention.

  The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an,” and “the” include plural forms as well, unless the phrases clearly indicate the opposite. As used herein, the meaning of "comprising" embodies a particular characteristic, region, integer, step, operation, element and / or component, and the presence of other characteristics, region, integer, step, operation, element and / or component It does not exclude the addition.

  Terms indicating relative space such as "below" and "above" may be used to more easily explain the relationship of one part to another part shown in the drawings. These terms are intended to include other meanings or operations of the device in use with the meanings intended in the figures. For example, if the device in the figure is reversed, any parts described as being "below" of the other parts are described as being "above" the other parts. Thus, the exemplary term "below" encompasses both up and down directions. The device can be rotated 90 degrees or at other angles, the terms representing relative space being interpreted accordingly.

  Unless defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Commonly defined terms used are additionally interpreted to have a meaning consistent with the related technical literature and the presently disclosed contents, and are not interpreted in an ideal or very formal sense unless defined.

  DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

 In general, the thin film filter may change the wavelength to be filtered according to the change of the light incident angle. The value of the changed wavelength has the following relationship.

Λ _o is the center wavelength of the filter when the light incident angle is 0 degrees, φ represents the incident angle, and n _eff represents the effective refractive index of the thin film filter.

In addition, the change of the wavelength to be filtered when the incident angle changes by 1 degree at the incident angle φ has a relational expression of [Equation 2].

3 is a diagram illustrating a change in wavelength to be filtered according to a change in incident angle.

FIG. 3 shows the change in wavelength 310 filtered by the thin film filter and the specific incident angle when the incident angle increases from 0 to 14 degrees in the thin film filter having a central wavelength of 1550 nm and an effective refractive index of 2.0 when the incident angle is 0 degrees. The amount of change 320 of the wavelength to be filtered is shown when the incident angle is further changed by one degree. Referring to FIG. 3, when the incident angle of the light filter is changed from 0 degrees to 10 degrees, the wavelength filtered by about 6 nm may be changed. If the incident angle is controlled to be 10 degrees in a filter designed to have a center wavelength of 1550 nm at an incident angle of 0 degrees, the center wavelength to be filtered is changed from 1550 nm to 1544 nm. In addition, referring to FIG. 3, when the incident angle is further changed from 10 degrees to 1 degree, the wavelength of about −1.2 nm is displaced. In other words, when the incident angle changes from 10 degrees to 11 degrees, the characteristic wavelength of the filter decreases from 1544 nm to 1542.8 nm.

4 is a diagram illustrating a configuration of an optical wavelength meter according to an exemplary embodiment of the present invention.

Referring to FIG. 4, an optical wavelength measuring device according to an embodiment of the present invention receives an optical signal including a plurality of optical wavelengths and transmits the optical signal by converting the optical signal into parallel light by using a lens. The optical unit 420 for analyzing the wavelength and the output of the optical signal received through the 410 to convert the electrical signal into an electrical signal, the control unit 430 for controlling the rotation angle of the motor 425 in the optical unit 420, the control unit ( 430 generates a rotation angle control signal and performs A / D conversion of the output of the optical unit 420, and extracts the optical wavelength value and the light output from the rotation angle and A / D converted output waveform and the magnitude of the output signal. The signal processing circuit unit 440 and the display unit 450 for displaying the measured wavelength and the light output.

  The optical input unit 410 is a module for receiving an optical signal transmitted through an optical cable, and may have an interface for receiving an optical signal from the optical cable. In addition, the light input unit 410 may include a lens 411 for making the received light signal into parallel light. The optical unit 420 includes a channel filter 422 and a channel filter 422 for filtering an optical signal for each channel, and are controlled by the rotating plate 424 and the control unit 430 which are rotated by the start of the motor 425. It may include a motor 425 for rotating the rotating plate 424 and a photo detector 423 for converting the optical signal passed through the channel filter into an electrical signal.

5 is a view showing the structure of the optical unit of the optical wavelength meter according to another embodiment of the present invention.

5, the optical unit 420 is coupled to the motor 425 and the motor shaft 426 to rotate the rotating plate 424 according to the control signal of the control unit 430 by the rotation of the motor shaft 426. Rotating plate 424 having a circular or regular polygonal shape that rotates together, a channel filter 422 attached to an outer circumference of the rotating plate 424, and a photo detector 423 for converting an optical signal passing through the channel filter into an electrical signal. Can be.

The rotating plate 424 may attach the channel filter 422 to the outer circumference, and may have a '-' shape in order to allow the photodetector 423 to detect the optical signal passing through the channel filter 422. Can be. That is, the center of the rotating plate 424 may be coupled to the motor shaft 426, and the radial end portion of the rotating plate 424 may include a protrusion 427 protruding in a direction opposite to the motor shaft 426. A plurality of channel filters 422 may be attached to the outer circumference of the protrusion 427, and the protrusions may face toward the center of the rotating plate 424 below the channel filter 422 so that an optical signal passing through the channel filter 422 may pass. The hole 428 may be drilled.

As shown in FIG. 5, a plurality of channel filters 422 may be attached to the circumference of the rotating plate 424. Each channel filter may be designed to have a different filtering center wavelength. That is, in the case of the CWDM channel filter, the channel filter may be designed such that the center wavelength has a 20 nm interval between 1270 nm and 1610 nm. The plurality of channel filters 422 may be attached to the circumference of the rotating plate 424 at equal intervals. As an example, when 16 CWDM channel filters are attached to each other, the CW plates may be attached to the rotating plate 424 with a spacing of 360/16 = 22.5 degrees. In addition, it is also possible to explicitly specify the angle at which a particular channel filter is located by making reference to the rotation angle. As an example, when 16 CWDM channel filters are attached, a reference may be set to 0 degrees when the channel filter having a center wavelength of 1270 nm is aligned with the light input unit 410 and the photo detector 423. Then, the channel filter having a center wavelength of 1290 nm may be positioned at 22.5 degrees, and the channel filter having a center wavelength of 1310 nm may be positioned at 45 degrees. In addition, a channel filter having a center wavelength of 1610 nm may be positioned at 337.5 degrees. Accordingly, by applying the plurality of channel filters 422 having different center frequencies to be filtered by rotating the rotating plate 422, various wavelengths included in the optical signal may be measured.

The light input unit 410 may arrange the parallel light outside the rotating plate 424 so that the parallel light may be incident on the channel filter 422 from the outside of the rotating plate 424, and the photo detector 423 may move the channel filter 422. The optical signal may be disposed to face the optical input unit 410 below the protrusion 427 of the rotating plate 424 so as to detect the optical signal that has passed. On the contrary, the photo detector 423 may be disposed outside the rotating plate, and the light input unit 410 may be disposed below the protrusion of the rotating plate to transmit the optical signal to the channel filter 422 through the hole 428.

The optical signal 413 to be measured is transformed into parallel light while passing through the lens 411 of the optical input unit 410. The optical signal 414 transformed into parallel light is incident on one of the channel filters 422. The channel filter to which the optical signal 414 is incident may be selected by manipulating the motor 425 under the control of the signal processor 440 and the controller 430. As an example, when 16 channel filters 422 are attached to the rotating plate 424 as described above, when the rotation angle of the motor 425 is rotated at intervals of 22.5 degrees, one channel filter 422a is selected from the 16 filters. ) Can be selected. Only light wavelengths within the transmission band range of the selected channel filter 422a among the incident optical signals 414 may pass through the selected channel filter 422a and may be input to the photodetector 423.

In addition, when the rotation angle of the motor 425 is smaller than 22.5 degrees, the incident angle of the optical signal 414 incident on the selected channel filter 422a may be changed. When the incident angle of the input optical signal 414 is changed, the transmission band of the channel filter 422a selected by Equation 1 is changed, and the wavelength included in the optical signal 414 according to the changed transmission band. And light output can be measured.

6 is a view showing the structure of the optical unit of the optical wavelength meter according to another embodiment of the present invention.

Referring to FIG. 6, unlike the case of FIG. 5, the rotating plate 424b may be a circular or regular polygonal plate having no protrusion having a center connected to the motor shaft 426. Of course, it is also possible to use the shape of the rotating plate 424 shown in FIG. The channel filter 422 may be attached perpendicularly to the surface of the rotating plate at the end of the rotating plate 424b. In this case, the channel filters 422 may be disposed such that the direction in which the optical signal 414 is incident is from the outer circumference of the rotating plate 424b to the center or the circumferential direction of the rotating plate 424b. The plurality of channel filters 422 may be attached to the ends of the rotating plate 424 at equal intervals. For example, when 16 CWDM channel filters are attached, they may be attached to the ends of the rotating plate 424 with a spacing of 360/16 = 22.5 degrees from each other.

7 to 9 are views for explaining the change in the incident angle and the transmission band of the channel filter by the rotation of the motor 425 of FIG. 5 or 6.

As described above, when 16 CWDM channel filters are attached to the rotating plate, for example, when the rotation angle of the motor 425 is changed to 22.5 degrees, channel filters having different center wavelengths are selected. However, when the rotation angle of the motor 425 is rotated smaller than 22.5 degrees, the incident angle (angle between the incident light and the normal of the surface of the channel filter) input to the same channel filter can be changed.

FIG. 7 illustrates that the optical signal 414 enters the center of the channel filter 422 at the incident angle of 0 degrees when the wavelength is measured while rotating one channel filter, without causing loss of the optical signal 414. FIG. 2 is a diagram for calculating rotation angles 720 and 721 capable of rotating the channel filter 422 as much as possible. The maximum rotation angle 720 may be calculated using Equation 3 by the size of the channel filter and the radius of the rotating plate to which the channel filter is attached.

Where L is the horizontal length 730 of the channel filter, which may be the length in the circumferential direction of the rotating plate 424, D is the beam diameter of the optical signal 414, and R is the rotational center of the rotating plate 424. The distance to the bottom surface of the channel filter 422, t represents the thickness 731 of the channel filter. In the case of L = 2.0mm, D = 0.3mm, R = 7mm, t = 1mm, the maximum rotation angle θ _max is about 6.1 degrees according to [Equation 3], and referring to FIG. 7, the maximum incident angle φ _max ) is about 6.1 degrees since it is equal to the maximum rotation angle. Therefore, the range of measurable incidence angles is φ = −6.1 to +6.1 degrees. According to Equation 1, in the case of a channel filter having a center wavelength λ _o = 1550 nm and an effective refractive index n _eff = 2.0, the wavelength displacement 740 is 0 nm to -2.2 nm.

FIG. 8 illustrates that when the wavelength is measured while rotating one channel filter, when the optical signal 414 is incident from the center of the channel filter 422 at the incident angle of 0 degrees, the optical signal 414 is not generated. 3 is a diagram for calculating a rotation angle 820 that can rotate the channel filter 422 as much as possible.

Referring to FIG. 8, the maximum rotation angle θ _max may be determined as follows by the size of the filter and the radius of the rotating plate to which the filter is attached.

  Where L represents the horizontal length 730 of the channel filter, which may be the length of the circumferential direction of the rotating plate 424, and X represents the offset 830 between the filter center and the input center of the optical signal 145. D denotes the beam diameter of the optical signal 414, R denotes the distance from the center of rotation of the rotating plate 424 to the bottom of the channel filter 422, and t denotes the thickness 731 of the channel filter. In this case, the offset 830 X should be smaller than (L-D) / 2 so that no loss of input light occurs.

According to Equation 4, when L = 2.0mm, D = 0.3mm, R = 7mm, t = 1mm, when the offset X is set to 0.55mm, the maximum rotation angle 820 may be 10.1 degrees. 8, the maximum incident angle φ _max may be about 10.1 degrees in the same manner as the maximum rotation angle. The range of measurable incidence angles can then be in the range φ = 0 to +10.1 degrees. According to Equation 1, the center wavelength λ _o = 1550 nm and the effective refractive index n _eff In the case of a channel filter of = 2.0, the wavelength displacement 840 is 0 nm to -5.9 nm.

  9 is another embodiment of the present invention for changing the angle of incidence, the beam of the optical signal 414 incident on the channel filter 422 to make the maximum angle of incidence larger so that a larger wavelength shift occurs than the method of FIG. It is a figure which shows the method of inclining itself and injecting into a filter. The maximum incident angle in this case can be calculated using [Equation 5].

Where? Is the tilt angle 930 of the optical signal 414, in which case the minimum measurable angle of incidence is not zero but?.

Under the same conditions as in the above example (L = 2.0mm, D = 0.3mm, R = 7mm, t = 1mm, X = 0.55mm), when the beam of the optical signal 414 is inclined by about 2 degrees, the incident angle ( φ) can vary from +2 degrees to 12.1 degrees. According to Equation 1, the center wavelength λ _o = 1550 nm and the effective refractive index n _eff In the case of a channel filter of = 2.0, the wavelength displacement 940 is -0.24 nm to -8.5 nm.

  In the embodiment of FIG. 9, since the incident optical signal 414 is reflected from the channel filter surface and returns to the incident part in a direction shifted by twice the tilt angle ψ, the reflection loss characteristic of the wavelength meter may be better.

  Table 1 is a table comparing the ranges of wavelength shifts that can be obtained by the method shown in FIGS. 7, 8, and 9 for the same channel filter and the same incident light.

  As shown in [Table 1], the maximum variable wavelength range can be increased by about four times by giving an offset to the incident position of the optical signal or giving an inclination slope.

	parameter		unit	7	8	9
Channel filter	Length (L)	mm	2.0	2.0	2.0
	Thickness (t)	mm	1.0	1.0	1.0
	Effective refractive index (n eff )	-	2.0000	2.0000	2.0000
Light signal	wavelength	mm	1550.0	1550.0	1550.0
	Beam diameter	mm	0.3	0.3	0.3
	offset	mm	0.0	0.55	0.55
	inclination	deg.	0.0	0.0	2.0
Tumbler	diameter	mm	7.0	7.0	7.0
angle of incidence	at least	deg.	0.0	0.0	2.0
	maximum	deg.	6.1	10.1	12.1
	range	deg.	6.1	10.1	10.1
Wavelength displacement	at least	nm	0.00	0.00	-0.24
	maximum	nm	-2.19	-5.94	-8.51
	range	nm	2.19	5.94	8.27

In the above-described embodiment, the wavelength change relation of Equation 1 is based on a channel filter having an effective refractive index of 2.0, but is not limited to a channel filter having an effective refractive index of 2.0. In general, when designing or fabricating a channel filter by stacking multilayer thin films, the effective refractive index is determined by the refractive indices of the dielectrics used for the lamination. According to Equation 1, when the effective refractive index decreases by 5%, the wavelength shift increases by 11%.

  For reference, since the incident angle between the input optical signal and the channel filter does not change even when the stepper motor 33 rotates, the conventional optical wavelength power meter as shown in FIG. 1 does not have the same effect as the present invention. The wavelength value cannot be measured.

  Referring back to FIG. 4, the signal processor 440 controls the motor 425 to rotate the rotating plate 424 to detect an electric signal coming from the photo detector 423 to precisely detect an optical wavelength included in the optical signal. It can be measured.

  Hereinafter, a wavelength measuring method performed by the signal processor 440 according to the present invention will be described with reference to FIGS. 10 to 12.

  FIG. 10 is a diagram illustrating an example in which a transmission band wavelength of the channel filter 422 is changed by changing the incident angle φ according to the rotation angle θ of the motor when the motor 425 is rotated.

The method proposed in the present invention for measuring the optical wavelength included in the input optical signal uses the wavelength of the left edge 1020 of the transmission band of the channel filter λ _LE and the wavelength of the right edge 1010 λ _RE . . Referring to FIG. 10, when the rotation angle θ of the motor is set to be perpendicular to the optical signal 414 to which each channel filter 422 is incident, that is, the incident angle φ of the optical signal 414 is zero. When set to be, the channel filter 422 can pass only the wavelength of the designed band at the designed center wavelength λ _C. As an example, when the channel filter is designed to pass only a wavelength of λc ± 7nm, the left edge wavelength λ _LE may be λc-7 nm, and the right edge wavelength λ _RE may be λc + 7nm. That is, when the center wavelength λ _C is 1550 nm, the left edge wavelength λ _LE may be 1543 nm, and the right edge wavelength λ _RE may be 1557 nm. Then, the right edge 1010 wavelength λ _RE and the left edge 1020 wavelength λ _LE of the transmission band of the channel filter when the motor 425 is rotated at each rotation interval dθ are calculated. When the motor 425 is rotated by dθ, the rotating plate 424 rotates in the same manner, and the channel filter 422 attached to the circumference of the rotating plate 424 also rotates by dθ. As a result, the incident angle φ at which the optical signal 414 is incident on the channel filter 422 becomes dθ. When the incident angle is changed from 0 to dθ, the wavelength band through which the channel filter 422 can pass is changed as described with reference to FIGS. 7 to 9. In general, as shown in FIG. 10, the left edge wavelength λ _REi and the left edge wavelength λ _LEi are changed accordingly. This change can be calculated using Equation 1. N channel filters are attached to the rotating plate 424, and for each channel filter, when N incidence angles (0, dθ, 2dθ, ..., (M-1) dθ) are calculated, a total of NxM You can get the data set for calibration.

Data k = θ _k , φ _j , λ _LE (i), λ _RE (i), dλ _LEj , dλ _REj

Where i = 1 to N, j is 1 to M, and k is 1 to N x M. θ _k is a value between 0 and 360 degrees as an angular position of the motor, and φ _j has a value of 0 to (M-1) dθ as an angle of incidence of an optical signal to the filter. dλ _j Is the wavelength shift value due to the change in the incident angle, dλ _REj is the displacement value of the wavelength at the right edge 1010, and dλ _LEj is the displacement value of the wavelength at the left edge 1020.

As an example, if the number of channel filters is 16, dθ is 0.5 degrees, and the calculation is performed for 20 incident angles, the total calibration data is 16 × 20 = 320. That is, as the number of incident angles to be calculated and the number of channel filters increases, the amount of calibration data may also increase. On the other hand, the measurable precision of the wavelength can be even higher. Under these conditions, the calibration data can have values as shown in Table 2 below.

k	i	j	θ k	φ j	λ LE (i)	λ RE (i)	dλ LEj	dλ REj
One	One	One	0	0	1263 nm	1277 nm	0nm		0nm
2	One	2	0.5	0.5	1263 nm	1277 nm	-0.012nm	-0.012nm
...	...	...	...	...	...	...	...	...
20	One	20	10	10	1263 nm	1277 nm	-4.796 nm	-4.796 nm
21	2	One	22.5	0	1283 nm	1297 nm	0nm		0nm
22	2	2	23	0.5	1283 nm	1297 nm	-0.012nm	-0.012nm
...	...	...	...	...	...	...	...	...
30	2	10	27.5	5	1283 nm	1297 nm	-1.225nm	-1.225nm
...	...	...	...	...	...	...	...	...
40	2	20	32.5	10	1283 nm	1297 nm	-4.871nm	-4.871nm
...	...	...	...	...	...	...	...	...
...	...	...	...	...	...	...	...	...
301	16	One	337.5	0	1603 nm	1617 nm	0nm	0nm
302	16	2	338	0.5	1603 nm	1617 nm	-0.015nm	-0.015nm
...	...	...	...	...	...	...	...	...
320	16	20	347.5	10	1603 nm	1617 nm	-6.080nm	-6.080nm

The calibration data may be stored in a nonvolatile memory included in the signal processor 440 of FIG. 4 and used for wavelength measurement.

FIG. 11 is a diagram for describing a method of measuring a wavelength of an input optical signal according to an exemplary embodiment.

Referring to FIG. 11, when an input optical signal having an unknown wavelength is incident on a wavelength detector, the signal processor 440 may measure the wavelength included in the input optical signal by observing the output of the photodetector 423. FIG. 11 assumes a case where an optical wavelength 1100 corresponding to a band of a specific channel filter is included in the optical signal 414. If the optical wavelength 1100 falls within the transmission band 1110 of the specific channel filter, the optical wavelength 1100 passes through the channel filter and is transmitted to the photo detector 425. The photodetector 425 may generate an electrical signal corresponding to the intensity of the optical wavelength to be reached and transmit the generated electrical signal to the signal processor 440. In the case of the conventional optical wavelength detector, it is possible to confirm only the existence of the optical wavelength corresponding to a specific channel by looking at the electric signal emitted from the photodetector 425, but cannot know the precise wavelength of the optical wavelength actually transmitted. The present invention uses the electrical output signal of the port detector 425 for precise wavelength measurement.

As shown in FIG. 11, the transmission band 1110 of the specific channel filter when the incident angle is 0 may be changed by rotating the rotating plate 424 and the channel filter 422 under the control of the signal processor 440. In the example of FIG. 11, when the angle is rotated by dθ, the incident angle becomes dθ, and thus the transmission band of the channel filter may be changed to 1120. If it rotates further by dθ, the incident angle becomes 2dθ and the transmission band of the channel filter becomes 1130. Continuously rotating by dθ further increases the angle of incidence and thus the transmission band of the channel filter continues to move to the lower side, whereby the incident light wavelength 1100 becomes the right edge of the channel filter transmission band 1140 when the incident angle becomes a × dθ. Is caught. As shown in FIG. 11, since the optical wavelength 1100 is present in the transmission band of the channel filter until the rotation angle of the motor 425 or the channel filter 422 is a × dθ 1150, the output of the photodetector 425 is high. If the value is maintained, but moved once more by dθ, the optical wavelength 1100 is out of the channel filter transmission band and cannot pass through the channel filter. As a result, the output of the photodetector 425 is hardly output. Since the optical wavelength 1100 does not exist in the channel filter transmission band, even if it is continuously moved by dθ and reaches the maximum rotation angle in one channel filter, the output of the photodetector 425 does not come out.

Therefore, the signal processor 440 may measure the precise wavelength of the optical wavelength 1100 input using the number of dθ shifted from the high point to the low point of the photodetector 425 and the pre-calculated calibration data. Can be. As an example, when k = 21 of the calibration data for a specific optical signal, the output of the photodetector 425 is k when the output of the photodetector 425 is high and the rotation angle is increased by 0.5 degrees (dθ). In the case of = 30, when the last high point is reached and k = 31 is the low point, the signal processor 440 determines the value of λ _RE (i) and dλ _REj at k = 30. By using the value it can be measured that the optical wavelength included in the input optical signal is 1297-1.225 = 1295.775 nm. Here, the high point and the low point of the electric signal may be a high point if the value is larger than this based on a predetermined value, and a low point if the value is smaller than this value.

  12 is a view for explaining a method of measuring a wavelength of an input optical signal according to another embodiment of the present invention.

  Referring to FIG. 12, when the optical wavelength included in the input optical signal is too far from the center wavelength of the original channel, the output of the photodetector 425 is very low when the first incident angle is zero. In this case, the conventional method can not recognize the channel and can be determined as an error, but it is not known what actually happened to the optical wavelength. On the other hand, in the present invention, the transmission band 1210 of the specific channel filter when the incident angle is 0 may be changed by rotating the rotating plate 424 and the channel filter 422 under the control of the signal processor 440. In the example of FIG. 12, when the angle is rotated by dθ, the incident angle becomes dθ, and the transmission band of the channel filter may be changed to 1220. If it rotates further by dθ, the incident angle becomes 2dθ and the transmission band of the channel filter becomes 1230. Continuously rotating by dθ further increases the angle of incidence and thus the transmission band of the channel filter continues to move to the lower side, whereby the incident light wavelength 1100 becomes the left edge of the channel filter transmission band 1240 when the incident angle becomes b × dθ. Is caught. As shown in FIG. 12, since the optical wavelength 1200 is outside the transmission band of the channel filter until the rotation angle of the motor 425 or the channel filter 422 is b × dθ 1250, the output of the photodetector 425 is If the rotation angle is b × dθ (1250) by moving it one more time by dθ, the optical wavelength 1200 enters the channel filter transmission band and passes through the channel filter. As a result, the photodetector 425 The output of) will show a high value. Afterwards, the optical wavelength 1200 remains in the channel filter transmission band until the maximum rotation angle in one channel filter is continued by dθ, so that the output of the photodetector 425 maintains a high value.

Therefore, the signal processor 440 may measure the precise wavelength of the optical wavelength 1200 input using the number of dθ moved from the low point to the high point of the photodetector 425 and the pre-calculated calibration data. Can be. As an example, when k = 21 of the calibration data for a specific optical signal, the output of the photo detector 425 is k when the output of the photo detector 425 is low and the rotation angle is increased by 0.5 degrees (dθ). If the highest point is reached in the case of = 30, the signal processor 440 determines the value of λ _LE (i) and dλ _LEj at k = 30. By using the value it can be measured that the optical wavelength included in the input optical signal is 1283-1.225 = 1281.775 nm.

  In summary, when the output of the photodetector 425 changes from the high point to the low point as shown in the example of FIG. 11, the signal processor 440 uses the following Equation 6 and the output of the photodetector 425 as shown in the example of FIG. 12. When the low point is changed to the high point, Equation 7 below can be applied to obtain an optical wavelength included in the input optical signal.

Where λ (i) is the measured wavelength value of the i-th channel, and λ _RE (i), λ _LE (i), dλ _REj and dλ _LEj are obtained from the pre-calculated calibration data, where i and j may be obtained based on channel information and rotation angle information at the time when the output of the photodetector 425 changes from a high point to a low point or from a low point to a high point.

On the other hand, the measurement of the light output of each channel is calculated by using the following equation (8) by dividing the photodetector output signal of FIG. 11 or 12 at the incident angle position and dividing by the previously measured Responsivity R value of the photodetector 425. can do.

I (i) is an output value of the photodetector 425 acquired at the incident angle position. In the present exemplary embodiment, the middle position of the section in which the photodetector 425 outputs a high signal is selected as the incident angle position for acquiring the light output. However, the left and right values of the middle position may be averaged.

In the case of measuring the wavelength by applying the wavelength measuring method of FIGS. 10 to 12, there may exist a range of measurable wavelength (λ _measure 1030) and a wavelength region (λ _ambiguity ) 1040 in which the wavelength cannot be measured. Measurement range and the measurement impossible region is a minimum angle of incidence (φ _min) wavelength displacement (dλ _min), the maximum incident angle (φ _max) wavelength displacement of the channel filter (dλ _max) in the channel and the channel of the for a single channel filter It is determined by the interval (dS _channel ), and can be obtained using Equations 9 to 13.

Where λ (0), λ (φ _min ) and λ (φ _max ) are the transmission bands of the channel filter at the incident angle of 0 degrees, the minimum incident angle, and the maximum incident angle, respectively, and λc is the center wavelength. The area where the wavelength obtained from Equation 13 cannot be measured may occur when the maximum wavelength shift (dλ _max ) is smaller than the transmission bandwidth (dλ _RE + dλ _LE ), in which case only the input optical signal is within λ _ambiguity Able to know.

If you want to measure the wavelength of λc-7.5nm ~ λc + 7.5nm using 18 CWDM channel filters, φ = +2 ~ 12.1 degrees, wavelength cuff dλ = -0.24nm--8.5nm as shown in the example of FIG. When dλ _min = -0.24nm and dλ _max = -8.5nm, dλ _LE = -8.5nm + 7.5 = -1.0nm according to Equations 10 to 12 and dλ _RE = 7.5nm + 0.24 nm = 7.74 nm. That is, by applying a channel filter having an angle of incidence of λc + 1.0nm to λc + 7.74nm at 0 degrees, all wavelengths in the range of λc-7.5nm to λc + 7.5nm can be measured.

 In addition, if the minimum rotation interval of the motor is dθ, the wavelength resolution can be obtained from Equation (14) below. Substituting dθ = 0.3 and the maximum incident angle of 12.1 degrees, the wavelength resolution becomes about 0.5 nm.

If the bandwidth of the channel filter when the incident angle is 0 degrees is not the same on the left and right sides of the channel center wavelength, and the longer wavelength is wider, the range of wavelengths that can be measured using the channel filter is larger than the bandwidth of the channel filter. Can be. For example, if 18 CWDM channel filters are used to measure wavelengths in the range of λc-9nm to λc + 9nm, φ = +2 to 12.1 degrees and wavelength displacement dλ = -0.24nm to -8.5 as shown in FIG. In the case of nm, dλ _min = -0.24nm and dλ _max = -8.5nm, and dλ _LE = -8.5nm + 9nm = + 0.5nm according to Equations 10 to 12 and dλ _RE = 9nm + 0.24 nm = 9.24 nm. That is, by applying a channel filter having λc-0.5nm to λc + 9.25nm at an incident angle of 0 degrees, all wavelengths in the range of λc-9nm to λc + 9nm can be measured. That is, in this embodiment, the bandwidth of the channel filter is 9.75 nm while the range of the band that can be measured is 18 nm. In this case, only the light output can be measured if the wavelength of the light input by [Equation 13] is within the range of λc-0.5- 0.24 to λc + 9.24-8.5, that is, λ _ambiguity of λc-0.74 to λc + 0.74. have.

  The technique of the present invention can be applied to DWDM networks as well as CWDM.

  FIG. 13 is a diagram illustrating an embodiment in which 100 GHz DWDM is applied to a C-band (1530 to 1565 nm and a bandwidth of 35 nm).

  DWDM technology as well as the C-band shown in Figure 13 can be applied to O-band, E-band, S-band, L-band, U-band.

FIG. 14 is a graph showing a relationship between an incident angle and a wavelength displacement of a DWDM filter having λ _o = 1570 nm and n _eff = 1.5764.

  Referring to FIG. 14, when the incident angle is 10 degrees, the maximum wavelength displacement is 9.5 nm, and the wavelength displacement (dλ / dφ) per degree is −1.18 nm / deg, so that the rotation step dθ is 0.05 degrees or less to obtain a wavelength resolution of 0.05 nm. Should be

  FIG. 15 is a diagram illustrating a configuration of an optical wavelength measuring device optical part for 100 GHz DWDM C-band according to an embodiment of the present invention.

  In the example of FIG. 15, a 50 GHz DWDM channel filter 429 having a transmission bandwidth of about 0.2 nm is applied, and the DWDM channel filter 429 may apply a channel filter having a transmission bandwidth of 0.2 nm or less. In the present embodiment, the DWDM channel filter 429 has a horizontal length L = 2.0 mm, a thickness t = 1 mm, an effective refractive index = 1.5764, a beam diameter of an input optical signal = 0.3 mm, an offset of an input optical signal X = 0.55 mm, and an input light. When the inclination angle ψ = 2 degrees of the signal, the incidence angle range of one filter φ = 2 degrees to 12.1 degrees and the wavelength displacement dλ = -0.38 to -13.89 nm can be obtained. Therefore, the number of DWDM channel filters for measuring wavelengths in the entire 35-band range of the C-band is at least four. In this embodiment, the DWDM channel filter 429 is used to use the maximum incident angle as an effective measurement value of only 8 degrees. Use dogs. Therefore, optical wavelength and light output can be measured for all C-band channels (total number of channels = 35nm / 0.8nm = 45) with seven 50GHz DWDM channel filters with transmission center wavelengths separated by 6nm. Referring to FIG. 14, when the incident angle is 8 degrees, since the wavelength displacement per degree is 1.53 nm, a motor having a minimum rotation angle dθ of 0.03 degrees may be applied to shift the filter transmission band at intervals of 0.02 nm. In addition, the DWDM channel filter 429 may be a filter having a narrow transmission band having a transmission band of 0.2 nm.

 Although the embodiment of FIG. 15 illustrates the measurement of the wavelength and the light output of the 100G DWDM optical signal by applying the 50G DWDM channel filter, the optical output may be measured even when the input signal is the 50G DWDM optical signal. However, in the case of 50G DWDM optical signal, the wavelength cannot be measured, and only the optical output value of each channel can be measured.

 If the wavelength and light output of the L-band DWDM optical signal are to be measured in the same manner as in FIG. 15, the L-band 50G DWDM channel filters may be attached instead of the C-band 50G DWDM channel filter 429.

 In addition, 7 DWDM channel filters may be attached to the rotating plate of FIG. 15 and additional CWDM channel filters 422 may be attached to the circumference of the remaining rotating plate to use DWDM / CWDM for common use, or L-band DWDM channel filters may be attached to the L- band DWDM channel filter. Can be used for both band / C-band.

  16 is a configuration diagram of an optical unit according to another embodiment in which the wavelength and the light output of the C-band 100 GHz DWDM optical signal are measured.

Referring to FIG. 16, the lens 411 according to the present exemplary embodiment may receive two optical signals 413 and 413a. The optical signal 413 is input from the outside as an optical signal to be measured that includes a plurality of optical wavelengths, and the optical signal 413a is an optical signal for wavelength calibration of the measuring instrument, which can be generated within the measuring apparatus presented in the present invention. have. That is, the optical input unit 410 may include two input ports, and the first input port may receive an external optical signal to be measured, and the second input port may receive a calibration optical signal and transmit the same to the lens 411. have.

  FIG. 17 is a diagram illustrating an embodiment of generating a calibration optical signal 413a.

  Referring to FIG. 17, in order to generate an optical signal 413a for wavelength calibration, the optical wavelength meter according to the present invention may include a calibration light source (for example, a 1550 nm SLD or 1550 nm LED) in addition to the configuration shown in FIG. 4. A light source generator 1720 capable of generating a light source, a driver 1710 driving the light source generator 1720, and light 1721 outputted from the light source generator to receive a light having a specific narrow band from among inputs having a wide wavelength line width. May further include an in-line 50G DWDM filter 1730 that transmits light and reflects an optical signal of the remaining wavelength to another output port 1732. The optical signal 1731 transmitted through the in-line 50G DWDM filter 1730 may be input to the second input port of the optical input unit 410 to become an input optical signal 413a of the lens 411.

  In FIG. 17, when the in-line 50G DWDM filter 1730 has a transmission bandwidth of 0.2 nm and the center wavelength is 1529.1633 nm (frequency 196.05 THz) defined by the 50G DWDM standard, the light transmitted through the in-line 50G DWDM filter 1730 is obtained. The wavelength spectrum is shaped like 1731a, and the center wavelength at this time is also 1529.1633 nm. The optical signal 1731 transmitted through the in-line 50G DWDM filter 1730 becomes an input optical signal 413a of the lens 411 and may be incident to the channel filter attached to the rotating plate. When a specific channel filter among the two channel filters is positioned at a specific rotation angle θ, the output signal of the photodetector may be maximized. Therefore, if the specific rotation angle of the motor is measured in advance, in order to check the absolute rotation angle of the motor, calibration can be performed with the configuration as shown in FIG. 17. If there is no output value of the photodetector at this calibration rotation angle position, It may be determined that there is an error in the motor function or an error in the optical unit. The calibration light source may use a wavelength stabilized light source for 50G DWDM. In this case, the calibration light source does not need to have a separate in-line 50G DWDM filter, and an output port of the 50G DWDM wavelength stabilized light source is input to the lens 411. May be connected directly to port 413a.

  As such, by generating and inputting an optical signal for calibration in the optical wavelength meter, it is possible to perform the function of calibrating the optical wavelength meter by itself.

  FIG. 18 is a diagram illustrating a wavelength band defined by a communication standard (E-PON, G-PON, GE-PON, 10G-PON, and NG-PON2) of a standardized optical subscriber network. Since the optical wavelength measuring instrument according to the present invention can attach a plurality of filters and change the angle of incidence of individual filters, it can be equipped with various kinds of filters having transmission bands suitable for various communication standards, The light output can be measured. The configuration of the filter for measuring the light output of all the channels shown in FIG. 16 is as follows. 1 1570 nm CWDM channel filter, 1 1310 nm CWDM channel filter, 1 1490 nm CWDM channel filter, 1 1260-1360 nm band pass filter, 2 DWDM filters for measuring wavelength and light output in the 1550-1560 nm band, 1580 nm DWDM One channel filter, one 1602nm DWDM filter, and three DWDM filters for measuring wavelength and light output in the 1524 ~ 144nm band. The 11 filters are divided into three groups, each group consisting of one broadband filter, three CWDM filters, and seven DWDM filters. Here, the DWDM filter may apply a filter having a bandwidth of 200 GHz, 100 GHz, 50 GHz, or 50 GHz or less.

  As those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features, the embodiments described above are intended to be illustrative in all respects and should not be considered as limiting. Should be. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. .

Claims (19)

1. An optical input unit for inputting an optical signal including a plurality of optical wavelengths and outputting the optical signal into parallel light using a lens;

   A channel filter for filtering the optical signal output from the optical input unit;

   A rotating plate to which the channel filter is attached;

   A motor for rotating the rotating plate;

   A photo detector converting the optical signal passing through the channel filter into an electrical signal and outputting the electrical signal;

   A control unit controlling a rotation angle of the motor;

   A signal processor for generating a rotation angle control signal for the controller and extracting an optical wavelength value based on the rotation angle and the electrical signal; And

   A display unit displaying the light wavelength value extracted by the signal processor; Including,

   Optical wavelength meter.
2. The method of claim 1,

   The electrical signal is an analog signal proportional to the intensity of the optical signal passing through the channel filter,

   The signal processor extracts the intensity of the optical signal based on the electrical signal,

   Optical wavelength meter.
3. The method of claim 1,

   The channel filter is attached in parallel with the tangent in the rotational direction of the rotating plate, the angle of incidence of the optical signal incident on the channel filter changes according to the rotation of the motor.
4. The method of claim 3, wherein the signal processing unit,

   An optical wavelength value included in the optical signal based on a rotation angle of the motor at a point where the electric signal changes from a high point higher than a preset reference value to a low point smaller than the preset reference value or the electric signal changes from a low point to a high point Extracting,

   Optical wavelength meter.
5. The method of claim 4, wherein the signal processing unit,

   Calculating a displacement of the transmission band of the channel filter according to the rotation angle of the motor, and extracting an optical wavelength value included in the optical signal based on the displacement;

   Optical wavelength meter.
6. The method of claim 5, wherein the signal processing unit,

   When calculating the displacement of the transmission band of the channel filter, the calculation based on the right edge wavelength or left edge wavelength of the transmission band,

   Optical wavelength meter.
7. The method of claim 3, wherein

   The optical input unit, the channel filter, and the photo detector are disposed on a straight line parallel to a straight line connecting the center and the circumference of the rotating plate,

   The channel filter is disposed between the optical input unit and the photo detector.

   Optical wavelength meter.
8. The method of claim 3, wherein

   The optical signal output from the optical input unit is input to the center of the channel filter,

   Optical wavelength meter.
9. The method of claim 3, wherein

   The optical signal output from the optical input unit is input offset from the center of the channel filter,

   Optical wavelength meter.
10. The method of claim 3, wherein

    The optical signal output from the optical input unit is input while being offset from the center of the channel filter and at an angle to the normal of the channel filter,

     Optical wavelength meter.
11. The method of claim 3, wherein

    In order that the wavelength range that can be measured by the channel filter is larger than the bandwidth of the channel filter, the bandwidth of the channel filter is narrow from the channel center wavelength to the short wavelength and wide toward the long wavelength at the incident angle of 0 degrees.

    Optical wavelength meter.
12. The method of claim 1,

    A light source generator capable of generating a light source for calibration;

    A driving unit for driving the light source generator; And

    It further comprises an in-line 50G DWDM filter for receiving the light output from the light source generator to transmit the light of a specific narrow band of the input of a wide wavelength line width and to reflect the optical signal of the other wavelengths,

    The optical input unit includes two input ports, the first input port receives an external optical signal for measurement, and the second input port is a calibration in which an optical signal generated by the light source generator passes through an in-line 50G DWDM filter. Receive the optical signal for

    Optical wavelength meter.
13. The method according to any one of claims 1 to 12,

    A plurality of channel filters are attached to the rotating plate,

    The plurality of channel filters may be classified into one or more groups.

    Channel filters belonging to the same group are composed of filters having the same bandwidth, characterized in that the transmission bandwidth is different or the wavelength band is different between the groups,

     Optical wavelength meter.
14. The method of claim 13,

    The plurality of channel filters are classified into one group,

    The first group is composed of a plurality of channel filters for 50G DWDM,

    Optical wavelength meter.
15. The method of claim 13,

    The plurality of channel filters are classified into one group,

    The first group is composed of a plurality of channel filters for 100G DWDM,

    Optical wavelength meter.
16. The method of claim 13,

    The plurality of channel filters are classified into two groups.

    The first group is composed of a plurality of CWDM channel filters,

    The second group is composed of a plurality of channel filters for DWDM,

    Optical wavelength meter.
17. The method of claim 13,

    The plurality of channel filters are classified into two groups.

    The first group is composed of a plurality of channel filters for 50G DWDM,

    The second group is composed of a plurality of channel filters for 100G DWDM,

    Optical wavelength meter.
18. The method of claim 13,

    The plurality of channel filters are classified into two groups.

    The first group is composed of a plurality of channel filters for C-band DWDM,

    The second group is composed of a plurality of channel filters for L-band DWDM,

    Optical wavelength meter.
19. The method of claim 13,

    The plurality of channel filters are CWDM channel filters having transmission bands according to the wavelength bands proposed by E-PON, G-PON, GE-PON, 10G-PON, and NG-PON2, which are standardized optical subscriber networks. , A wideband filter, and a DWDM channel filter having a transmission band of 200 GHz, 100 GHz, 50 GHz, and 50 GHz or less.

    Optical wavelength meter.

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