JPH10213543A - Optical time area reflectance gauge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To test the operational ability of an optical network which is being operated by suppressing a communication signal in a measuring section and transmitting only a measuring signal having a different wavelength to an optical detector in a filter device to be switched. SOLUTION: In a gauge, a laser source 1 produces the wavelength 1.31μm of a communication signal and laser sources 2 and 3 respectively produce measured wavelengths 1.55μm and 1.65μm longer than that of the communication signal. The laser sources 2 and 3 are connected to a wavelength dependence connector (WOM) 4, the laser source 1 is connected to a WOM 5, the WOM 5 is connected to the WOM 4, measured wavelengths thereof are inputted to a wavelength independent connector(WIC) 6 and connected to the output 10 of the gauge. Further, the output of the WIC 6 is inputted to a filter device (SWF) 8 to be switched and transmitted to an optical detector 9. In this case, the SWF 8 transmits only the measured wavelength of 1.65μm while the reflectance of 1.3μm and 1.55μm wavelengths is 0. Thus, a reflection signal is detected without being interfered by the communication signal and the operational ability of an optical network which is being operated is accurately tested.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring instrument for measuring a reflected signal reflected from a light measuring section to be measured.

[0002]

2. Description of the Related Art An optical time domain reflectometer (OTDR) is
Usually used for monitoring and error analysis of optical fibers and networks constructed therefrom. Generally, communication traffic in the segment being measured is turned off due to the measurement. Permanent, or at least periodic monitoring, allows early intervention in the event of degradation and provides advance warning to the network operator before the network fails.

[0003] Many recent networks use multiple wavelengths for data transmission. In some cases, transmission may occur alternately in both directions of the line. When monitoring and characterizing or measuring such a network, the measurement signal (ie, the signal backscattered or reflected from the network when the measurement wavelength is applied)
In order to prevent the signal from being distorted or excessively attenuated, meaningful measurement cannot be performed, a measurement wavelength different from the communication signal (traffic signal) must be used.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a measuring instrument for testing the performance of an operating optical network by measuring the reflected light signal.

[0005]

SUMMARY OF THE INVENTION The main concept of the present invention is as follows.
Prior to the detection device for measuring the optical signal reflected by the optical measuring section, the communication signal with one or more different wavelengths in the measuring section is suppressed or at least greatly attenuated, for example by avalanche The placement of a switchable filter device that allows the transmission of the reflected light measurement signal to the light detection device of the measuring device, such as a photodiode (APD).

The instrument of the present invention is particularly useful for measuring the reflected signal of an optical measurement section, for example, a fiber optic network, a portion or section of a network, or an optical component in such a network. O to measure the reflected light signal
In the case of TDR, a measurement signal at a measurement wavelength is coupled to a measurement section, and the reflected signal to be measured is detected by a photodetector and sent to a computer for quantitative analysis and visual display.

In order to be able to carry out measurements in a network operating on communication signals, the invention proposes to generate a signal of a different measurement wavelength than the communication signal and to couple it to the measurement section. Preferably, the measurement signal is coupled at a wavelength longer than the longest wavelength of the communication signal. To enable an accurate measurement, the invention further proposes to arrange a switchable filter device in the optical path between the measuring section and the optical measuring device. The switchable filter device allows signals that are optically scattered or reflected by the measurement section under test to be transmitted to the detection device and the communication signal is sufficiently attenuated to prevent effects on the detection device, or It is at least greatly reduced.

According to an advantageous embodiment of the invention, the filter arrangement according to the invention usually has some of the optics necessary to keep all applied communication signals away from the detector (APD). It is designed to accommodate a filter, or even all optical filters.

In another advantageous embodiment of the invention, all the filters available in the filter device are fed sequentially into the optical path between the measuring section and the detection device (APD). If the insertion of a filter for a particular wavelength does not affect the measurement signal returned from the detection device (APD), it indicates that no communication signal with the wavelength of the filter is present in the measurement section. These wavelengths are compatible with subsequent measurements in the measurement section. If the insertion of a filter for a particular wavelength would affect the measurement signal returned from the detector (APD), this would, conversely,
It indicates that a communication signal with a corresponding wavelength is present in the measuring section, and such a wavelength is used for measuring the measuring section by the measuring device of the present invention in order to minimize the influence on the reflected signal of the measuring section. Do not use. For practical reasons, a filter of a wavelength whose insertion into the optical path affects the measurement signal returned from the detector (APD) is left in the optical path in preparation for the measurement,
Filters of unaffected wavelengths are intended to be removed from the optical path in preparation for measurement. If all available filters of the inventive filter device are inserted into the optical path, it is set which measuring wavelength of the inventive measuring instrument is available for measuring the measuring section. If this has not already been done in the measurement preparation, the filter of at least this measurement wavelength is removed from the optical path before performing the actual measurement in the measurement section where the communication signal is applied.

Of course, if no filter is introduced in the optical path of the filter device of the present invention, it is also possible to use a detection device to indicate the optical power generated in the optical measurement section.

For practical reasons, the measuring device of the present invention includes:
Control means are provided for mechanically inserting the filter into the optical path of the filter device. This control means can be realized as a hardware solution or a software solution, and for convenience implements mechanical or electrical settings for measurement by the measuring instrument and its components, or The setting is to be obtained. As mentioned earlier, for practical reasons,
Which measurement wavelength should be used for the measurement of the measurement section is set.

In a further advantageous embodiment of the invention, the measuring instrument according to the invention has a function for generating a commonly used measuring wavelength which can be identical to a normal communication signal.
One or more signal sources are designed.

For practical purposes, according to another advantageous embodiment of the invention, the measuring instrument according to the invention controls the wavelength of the signal source, as already mentioned, in the measuring section. Is provided with a control means (hardware or software solution) for emitting a measurement signal, the measuring device of the invention uses a detection device (APD) and a subsequent computing device to measure the result of the reflection signal. Ask. The measured data can be displayed visually or fed into a comparator, which can be used, for example, to alert when a predetermined deviation occurs. Thus, for example, an important optical network can be permanently monitored for its operational capabilities without human involvement. Furthermore, the measuring device of the present invention can be composed of a minimum device equipped with a filter of the filter device of the present invention, which is suitable for embodying the communication signal of the network concerned.

As is apparent from the above description, according to the present invention, the operating capability of the optical measurement section to which the communication signal is applied is not required, without having to switch off the measurement section for performing the measurement. It becomes possible to realize a fully automatic measuring device for measuring.

Furthermore, advantageously, the measurement device of the present invention can be used to perform measurements in an optical measurement section to which a communication signal has been applied, so that only one connection to the measurement section is required. , And a detection device (A
Only one PD) is required. In the case of a single component, a flexible and cost-effective adaptation of the measuring wavelength to the communication wavelength occurring in the measuring section is possible. According to the wavelength of the communication signal generated in the measurement section,
It is possible to insert filters having different configurations such as high-pass, low-pass, or band-pass into the filter device of the present invention.

This results in a slight difference (typically 2n
so-called WDM (wavelength division multiplexing) in which a large number of communication signals of various wavelengths (communication channels) having
It is also possible to use the measuring device of the present invention in the system, and the measuring wavelength in the measuring system of the present invention can be selected to be compatible with the free channel.

Furthermore, the switchable filter device of the present invention can be incorporated into an existing optical time domain reflectometer by placing it between the output of an existing measuring instrument and the measuring section to be tested.

In one embodiment of the present invention, the measuring instrument of the present invention includes one or more signal sources for generating a measurement wavelength longer than the wavelength of the communication signal in the measurement section. In the case of the measuring device according to the invention, 1.65 μm, 1.55 μm and / or
It is desirable to intend to use an optical signal source that generates a measurement wavelength of 1.31 μm (the wavelength of a typical communication signal). As mentioned above, in order to prevent interference by communication signals of the same wavelength, it is preferable to use a measurement wavelength different from that of the communication signal generated in the measurement section from a set of measurement wavelengths available in the measuring instrument of the present invention. A signal is coupled to the measurement section. Customary for the measuring section,
Alternatively, if one wavelength of the potential communication signal is not used for it, the measurement wavelength can be the wavelength of the communication signal.

In order to generate a signal having a measurement wavelength in the measuring instrument of the present invention, the OTDR module includes a first laser source, a second laser source, and a third laser source for generating the aforementioned measurement wavelength. Are provided.

Of course, the number of signal sources provided for generating a signal with a suitable measurement wavelength can be increased or decreased. Similarly, the light source can be designed to generate a measurement wavelength different from the aforementioned measurement wavelengths, if it is compatible with the measurement of the optical measurement section. The selection of the intended measurement wavelength is made in particular to adapt to the communication network for which the measuring instrument of the present invention is designed, and to the communication wavelength usually occurring in the communication network.

In a possible embodiment of the invention, between the output of the measuring instrument of the invention and the signal source generating the measurement wavelength,
Each is intended to arrange at least one or more wavelength-dependent couplers. Similarly, it is intended to use a wavelength dependent coupler between any two signal sources. The measurement wavelength that emerges from the last wavelength-dependent coupler in the output direction of the measuring device is connected via an optical fiber to the input of a wavelength-independent coupler. The input of the wavelength independent coupler is also connected to a detection device (APD) via the inventive switchable filter device with one or more optical fibers. The output of the wavelength independent coupler is connected via an optical fiber to the output of the measuring instrument of the present invention for connection to the measuring section. The output of the wavelength independent coupler is connected to a monitor photodiode, again via an optical fiber. monitor·
The photodiode detects the signal fed into the measuring section, compares the reference value with the wavelength and / or signal height of the measuring wavelength fed into the measuring section and, if necessary, adjusts it by affecting the signal source. And the configuration of the control circuit. 1 for measuring section
Since only one measurement wavelength is transmitted, it is possible to ensure that only a single suitable signal source is controlled by the control of the measuring instrument. Also, all signal sources are used to generate the available measurement wavelengths, and overall wiring is provided to ensure that only selected, suitable measurement wavelengths are sent to the output of the meter, electrically. It is also possible that an active blocking device is assigned to each signal source.

In a preferred embodiment of the present invention, for example,
From laser diodes emitting wavelengths of 1.31 μm, 1.55 μm, and 1.65 μm, one or all signal sources for generating a wavelength are created. The detection device is, for example, an avalanche photodiode (AP)
D).

Preferably, the switchable filter device (SWF) is located in the optical path between the detector (APD 9 and the input of the wavelength independent coupler (WIC). It can also be placed in the optical path between the output of the measuring instrument (WIC) and the port of the measuring instrument (OTDR port) for connecting the measuring instrument to the measuring section.
F) can also be placed between the output of the measuring device of the invention or, for example, between the output of the existing measuring device and the measuring section to be tested, so as to be compatible with the existing measuring device.

In one embodiment of the present invention, the switchable filter device (SWF) has a first optical lens at its input and a second optical lens at its output.
In the optical path between the first lens and the second lens, one is provided to attenuate communication signals generated in the optical measurement section.
One or more optical filters are provided. For example, the optical filter may be, for example, by an operator, or
If possible, it can be moved manually or by an electrically actuated actuator via a control device provided with the control means of the invention described above.

A switchable filter device (SWF) is connected in series and can be moved in the optical path for various wavelengths, in particular 1.31 μm, 1.55
It can be made up of a number of optical filters for wavelengths of μm and / or 1.65 μm. On the axis of the actuator, for example, in the form of a slider or a filter wheel with several filters rotating in the optical path, it is fed into the optical path of a switchable filter device (8, SWF) one after the other. , And can stack, or either,
It is possible to assemble one or more optical filters.

In another embodiment of the invention, one or more optical filters which can be tilted by the actuator are arranged on the axis of the actuator in the optical path of the switchable filter device (SWF). Such a solution, especially when the wavelengths of the communication signals are close to each other, is a switchable filter device (SWF), since the wavelength affected by the filter and the filter characteristics is determined by the arrangement angle of the filter in the optical path.
Can be made in time with a small number of optical filters.

One or more of the actuators affecting the switchable filter device (SWF) may be rotated, tilted, or swung in one or more of the optical filters of the switchable filter device (SWF) to provide an optical path in the optical path. It can be designed so that it can be sent to
The actuator can be driven electrically, for example, by a rotating magnet, or a stepper motor or linear drive and / or an oscillating plate can be used. Advantageously, when a wobble plate is used, it is possible to allow a slight change in the tilt angle of the filter fed into the optical path of the switchable filter device (SWF) at large rotation angles.

In another embodiment of the present invention, one or more filters of the switchable filter device (SWF) include:
Made by an electrically controllable acousto-optic filter.

In yet another embodiment of the present invention,
The detection device (APD) is not via an optical fiber,
Directly connected to the lens at the output of the switchable filter device (SWF). If the detection device (APD) is connected via an optical fiber to the lens at the output of the switchable filter device (SWF), this is usually via a thinner so-called single-mode fiber, 9 μm thick. Instead, it is preferable to carry out through a thicker optical fiber having a thickness of, for example, 50 μm. If it is desired to place a customary 9 μm thick fiber at the input of the switchable filter device (SWF), a mapping from thin fiber to thick fiber occurs. by this,
The high thermal stability of the arrangement according to the invention is obtained, and a simpler adjustment is possible.

In the embodiment of the present invention, a collimator lens, a gradient lens (a gradient index lens),
The switchable filter device (S) according to the present invention, wherein the spherical lens and / or the dichroic lens is located before and after the optical path.
WF) at the input or output.

The housing of the switchable filter device (SWF) provided with a bore for the optical path can be made, for example, from metal. Furthermore, it is possible to arrange conical bores for accommodating optical fibers, respectively, on the left and / or right of the bore at the input and / or the output of the switchable filter device (SWF).

In order for the filter of the switchable filter device (SWF) to be movable in the optical path, the filter may be arranged, for example, like a throttle valve in a carburetor, arranged in series in the optical path of the switchable filter device. It is possible to provide one or more forks for mounting.

Similarly, a switchable filter device (SW
F) One or more filters can be fed manually or electrically into the optical path of the switchable filter device (SWF), such as a sealing cap that operates at the edge of the housing of the switchable filter device. is there.

It goes without saying, but to emphasize even more clearly, that the available invention is characterized by the independent features mentioned above, as well as all useful and novel features of the features in any combination. Represents a combination. Furthermore, all the advantages described above can be considered as solutions to the tasks and problems obtained by the present invention.

The invention will now be described in more detail with reference to a simple sample embodiment.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The module of the measuring instrument according to the invention according to FIG. 1 comprises a first laser source 1 (LD 1.31), a second laser source 2 (LD 1.55) and a third laser source 3 (LD 1.
65) is included. Second and third laser sources 2 and 3
Is a wavelength-dependent coupler 4 via optical fibers 32 and 31.
(WDM1). The second wavelength-dependent coupler 5 (WDM2) has its input connected to the first laser source 1 via an optical fiber 34, and also at its input, the output of the first wavelength-dependent coupler 4 It is connected. The output of the second wavelength-dependent coupler 5 is the optical fiber 37
Is connected to the input of the wavelength independent coupler 6 (WIC6). Further, the input of the wavelength independent coupler 6 is also connected via an optical fiber 36 to the input of the switchable filter device 8 (SWF) of the present invention. The output of the switchable filter device 8 (SWF) is connected via an optical fiber 35 to a light detection device 9 such as, for example, an avalanche diode (APD). The switchable filter device 8 (SWF) is connected via a wire 40 to the final control element 11. The output of the wavelength independent coupler 6 (WIC) is connected to the monitor photodiode 7 (PD) via the optical fiber 38 and to the output 10 of the measuring instrument of the present invention via the optical fiber 39.

A simple filter device 8 (SW shown in FIG. 2)
F) shows a metal housing with a bore 22 forming an optical path. A conical bore (not shown) for receiving the optical fiber 36 is provided at an input of the filter device 8 (SWF), and a photodiode 9 (APD) is provided at the output of the filter device at the other end. There is provided a conical bore (not shown) for accommodating an optical fiber 35 optically connected to the optical fiber 35.

The optical filter 24 includes an actuator 25
Thereby, it can be reversibly inserted into the optical path of the filter device 8 (SWF) in a slider manner. The collimator lens 23 is arranged between the optical fiber 36 and the optical path 22, and the collimator lens 21 is arranged between the optical fiber 35 and the optical path 22. The reflected signal emitted by the optical measurement section to be measured is
3, guided into the photodetector via the optical path 22 and the lens 21.

FIG. 3 shows the transmission T of the light path of the switchable filter device as a function of the wavelength λ for three typical cases.

In the first case 0, no communication signal occurs in the measurement section. The module according to FIG. 1 shows at its output a measurement signal at a wavelength of 1310 nm or 1550 nm or 1650 nm. The optical filter of the filter device 8 is not fed into the optical path. The transmittance of the optical path is high. In the graph of FIG. 3 (transmittance T vs. wavelength λ), this is indicated by a line called 0 parallel to the X axis.

In the second case 1, the measurement section shows a communication signal with a wavelength of 1310 nm. 1310n
A filter 24, shown in FIG. 2, which attenuates m wavelengths, is fed into the optical path of the switchable filter device 8 (SWF). The module according to FIG. 1 shows at its output a measurement signal with a wavelength of 1550 nm or 1650 nm,
This measurement signal is fed into the measurement section to be measured, and the measurement signal reflected from the measurement section is guided to the detection device (APD) via the filter device according to the invention, as can be seen from FIGS. The transmittance of the optical path is 1
For a wavelength of 310 nm, it is nearly zero and 155
Wavelengths in the region of 0 nm or 1650 nm pass with very little blocking. This is represented by the transmittance plot 1 of FIG. 3, where the transmittance of the optical path 22 of FIG.
It becomes almost zero in the region of nm, increases rapidly in the region below 1550 nm, and reaches its maximum value in the region of 1550 nm or more. For wavelengths in the region of 1550 nm and above, the optical path 22 of FIG. 2 acts almost as if no filter was inserted in the optical path of the filter device of the present invention.

In the third case 2, the measurement section shows communication signals with wavelengths of 1310 nm and 1550 nm. Instead of the filter 24 shown in FIG. 2, a filter not shown is fed into the switchable filter device 8 (SWF), and the module according to FIG. 1 shows at its output a measurement signal with a wavelength of 1650 nm. The filter of the filter device of the present invention, which is not shown in FIG. 2, shows transmittance characteristics according to the transmittance plot 2 shown in FIG. The transmission of the optical path is almost zero for 1310 nm and 1550 nm, the wavelength in the region of 1650 nm can be passed almost unblocked, and the reflected signal of the measuring section can be detected without interference of the communication signal. Can be.

Of course, the measurement in the third case 2 can be performed, for example, by inserting two filters in the optical path 22. In this case, the two filters are used such that the first filter causes attenuation in the region of 1310 nm and the second filter causes attenuation in the region of 1550 nm.

Those skilled in the art, with an understanding of the teachings of the present invention, will be required to make measurements of the signal reflected in the measurement section where the traffic signal is present, in order to make a measurement in relation to the respective situation. Band pass filter,
It will be clear how low pass filters, or other optical filters, such as band pass filters, must be combined.

The embodiments of the present invention have been described in detail above. Hereinafter, examples of each embodiment of the present invention will be described.

[Embodiment 1] One or more optical signal sources (1, 1) for generating signals having different wavelengths (measurement wavelengths)
2 and 3) and a communication signal (1310 nm, 1550n) having at least one wavelength different from the wavelength of the measurement wavelength.
m, and 1650 nm) for measuring the reflected signal produced by the optical measurement section measured using one or more wavelengths of the optical signal source (1, 2, and 3). A measuring device (OTDR) for measuring a reflected light signal by a detecting device (9, APD), wherein the measuring section and the light detecting device (9, AP)
D) in the optical path, passing the optical signal reflected from the measuring section in the direction of the detection device and one or more communication signals (1310 nm, 1550 nm and 1650 nm)
nm) is provided with a switchable filter device (8, SWF) that is not sent to said detection device or at least greatly attenuates.

[Embodiment 2] One or more wavelengths of the optical signal sources (1, 2, and 3) that generate the measurement wavelengths correspond to the communication signal wavelength (1310 nm,
The measuring instrument according to embodiment 1, wherein a signal having a wavelength longer than 1550 nm and 1650 nm) is generated.

[Embodiment 3] The measurement wavelength is 1.65 μm.
m, 1.55 μm, and 1.31 μm, and the measurement section in which the communication signal (1310 nm, 1550 nm, and 1650 nm) is present at a measurement wavelength different from the wavelength of the communication signal. Embodiment 1 or 2 characterized by being used for measurement of
The measuring device according to 1.

[Embodiment 4] A first laser source (1, LD 1.31), a second laser source (2, LD 1.55) and / or a third laser are provided in a measuring instrument OTDR module (FIG. 1). Source (3, LD 1.65), detector (APD),
One or more wavelength-dependent couplers (4, WDM1, 5, WDM
2), wavelength independent coupler (WIC), monitor photodiode (PD), and switchable filter device (SW)
A measuring instrument according to any of the preceding embodiments, wherein F) is provided.

[Embodiment 5] The first, second, and / or third laser sources (1, 2, and 3) have a wavelength of 1.3.
The measuring instrument according to embodiment 4, characterized in that it comprises a laser diode (LD) emitting a wavelength of 1 μm, 1.55 μm or 1.65 μm.

[Embodiment 6] The detection device (9, APD)
5. The measuring device according to claim 1, wherein the measuring device comprises an avalanche photodiode (APD).

[Embodiment 7] Two laser sources (2 and 3)
Are respectively the first and second optical fibers (31 and 3).
2) to the input of the first wavelength-dependent coupler (4, WDM1) via the second wavelength-dependent coupler (4, WDM1).
The output of 1) is a second wavelength-dependent coupler (5, WDM2)
And the third laser source (1,
LD 1.31) is also coupled to the input of said wavelength-dependent coupler (5, WDM2) via an optical fiber (34).
7. The measuring device according to 6.

[Embodiment 8] The output of the second wavelength-dependent coupler (5, WDM2) is the fifth optical fiber (37).
And optically connected to the input of a wavelength independent coupler (6, WIC) through the switchable filter device (8, SW
The output of F) is also the wavelength independent coupler (6, WIC)
Measuring instrument according to any of the preceding embodiments, characterized in that it is optically connected to an input of the measuring instrument.

[Embodiment 9] The switchable filter device (8, SWF) is disposed in an optical path between the detection device (9, APD) and the input of the wavelength independent coupler (6, WIC). The measuring instrument according to any of the preceding embodiments, characterized in that:

[Embodiment 10] The switchable filter device (8, SWF) includes the wavelength-independent coupler (6, WI).
C) A measuring instrument according to any of the preceding embodiments, which is arranged in the optical path between the measuring instrument and a port (10) for connecting the measuring instrument to the measuring section. .

Embodiment 11 The switchable filter device (8, SWF) is arranged in an optical path between an output (10) of the measuring device and the measuring section. A measuring device according to any of the embodiments.

[Embodiment 12] The wavelength independent coupler (6,
WIC) also outputs via optical fiber (38)
A measuring instrument according to any of the preceding embodiments, further connected to a monitor photodiode (7, PD) for monitoring and adjusting the optical signal originating from the measuring instrument.

Embodiment 13 The switchable filter device (8, SWF) has a first optical lens (23) at its input and a second optical lens (21) at its output.
A communication signal (1310 nm, 1550 nm, and 1650 nm) present in the optical measurement section in an optical path between the first and second lenses (23, 21).
Measuring instrument according to any of the preceding embodiments, characterized in that it comprises one or more optical filters (24) for attenuating.

[Embodiment 14] The communication signal (1310)
, 1550 nm, and 1650 nm) of the switchable filter device (8, SWF) by one or more electrically or mechanically actuated actuators (25). 14. The measuring device according to embodiment 13, wherein the measuring device is moved in an optical path.

Embodiment 15 The switchable filter device (8, SWF) has different wavelengths, especially 1.31.
Embodiment 15. The measuring instrument according to embodiment 14, characterized in that it comprises several filters fed in series in the optical path for μm, 1.55 μm or 1.65 μm.

[Embodiment 16] In the optical path of the switchable filter device (8, SWF) one after another, such as a slider or a filter wheel having several filters rotating in the optical path. Sending in, and
15. The measuring instrument according to embodiment 14, characterized in that several optical filters, which can be stacked or both, are arranged on the axis of the actuator (25).

[Embodiment 17] One or more optical filters are arranged on the axis of the actuator, and the actuator (25) inclines the filter so that an optical path of the switchable filter device (8, SWF) is provided. The measuring device according to embodiment 14, wherein the measuring device is fed into (22).

[Embodiment 18] One or more optical filters are fed into the optical path of the switchable filter device (8, SWF) by rotation, tilt, or swing by one or more actuators (25). A measuring instrument according to any of the preceding embodiments, characterized in that:

[Embodiment 19] The actuator (2)
5) is electrically driven by a rotating magnet;
With a large rotation angle, the switchable filter device (8, S
Any of the preceding embodiments, characterized in that a step motor or a linear drive and / or an oscillating plate is used that allows a small change in the tilt angle of the filter fed into the optical path of the WF). The measuring device described in Crab.

[Embodiment 20] In the above embodiment, one or more filters of the switchable filter device (8, SWF) include an electrically controllable acousto-optic filter. The measuring device according to any one of the above.

[Embodiment 21] The detection device (9, AP
D) directly at the output of said switchable filter device (8, SWF) without passing through an optical fiber;
Or the detection device (9, APD) is replaced by a thicker optical fiber (35) of, for example, 50 μm instead of the commonly used fiber of 9 μm. And connected to the output of said switchable filter device (8, SWF).
A measuring device according to any of the above embodiments.

[Embodiment 22] The optical lens (23,
21. The measuring instrument according to any of the preceding embodiments, wherein one or both of 21) is a collimator lens, a gradient lens, a spherical lens, and / or a dichroic lens.

[Embodiment 23] For example, the housing of the switchable filter device (8, SWF) provided with a bore for the optical path (22) is made of metal, and the switchable filter device is formed of metal. (8, SWF) At the input and / or output of the bore, on the left and / or right of the bore, there is provided a conical bore for accommodating optical fibers (35, 36). The measuring device according to any one of the above.

Embodiment 24 One or more filters (24) of the switchable filter device (8, SWF) are arranged in series, for example, in the optical path (22) of the switchable filter device, and Configured to rotate in the light path (22) of the switchable filter device (8, SWF) with the aid of one or more forks functioning as a throttle valve of the invention. A measuring device according to any of the above embodiments.

Embodiment 25 One or more filters of the switchable filter device (8, SWF) act like a sealing cap operating at the edge of the housing of the switchable filter device (8, SWF). And manually or electrically the switchable filter device (8, S
A measuring instrument according to any of the preceding embodiments, characterized in that it can be positioned in the optical path of WF).

[0072]

As described above, by using the present invention, the reflectance for measuring the operation capability of the optical measurement section to which the communication signal is applied without turning off the measurement section to be measured. A measuring instrument can be realized. This measuring device can be a fully automatic measuring device.

[Brief description of the drawings]

1 shows a module of a measuring device according to the invention for measuring a signal reflected from a measuring section, comprising a switchable filter device, three signal sources and a detecting device.

FIG. 2 is a detailed view of the switchable filter device of the present invention.

FIG. 3 shows the transmission T of the optical path of the switchable filter device as a function of the wavelength λ, with and without a communication signal in the optical measurement section to be measured.

[Explanation of symbols]

 1: First laser source 2: Second laser source 3: Third laser source 4: First wavelength dependent coupler 5: Second wavelength dependent coupler 6: Wavelength independent coupler 7: Monitor photo Diode 8: Switchable filter device 9: Photodetector 10: Output of measuring instrument 21: Collimator lens 22: Optical path 23: Collimator lens 24: Optical filter 31: Optical fiber 32: Optical fiber 34: Optical fiber 35: Light Fiber 36: Optical fiber 37: Optical fiber 38: Optical fiber 39: Optical fiber

Claims (1)

[Claims] At least one optical signal source for generating a signal having a different wavelength (measurement wavelength) and a communication signal having one or more wavelengths different from the wavelength of the measurement wavelength are applied. An optical measurement section that is measured using one or more wavelengths of the optical signal source; and a light detection device for measuring a reflected signal produced by the optical signal source, wherein the measuring device measures the reflected light signal. In the optical path between the measuring section and the light detecting device, pass the optical signal reflected from the measuring section in the direction of the detecting device so that one or more communication signals are not sent to the detecting device. Or at least a switchable filter device for greatly attenuating is arranged.