JP6986773B1 - Optical device inspection machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical device inspection machine capable of collectively performing insertion loss measurement of an optical device, reflection attenuation measurement, and inspection of disconnection and cracks. SOLUTION: An optical device inspection machine 1 has a light source 3 that emits a wide band and low coherence light L in a housing 2, a beam splitter 4 that branches the light L into a measurement light L1 and a reference light L2. It includes a reference mirror 5 for adjusting the optical path length of the reference light L2, and a first optical measuring instrument 6 for receiving the measurement light L1'reflected by the optical device C and the reference light L2'reflected by the reference mirror 5. Further, the connection portion 7 connected to the outside of the housing 2, the transmitted light input unit 8 provided apart from the connection portion 7, and the measurement light L1 incident on the housing 2 from the transmitted light input unit 8 are received. A second optical measuring instrument 9 is provided. The optical device C is connected to the connection unit 7, the light receiving amount of the first and second optical measuring instruments 6 and 9 is calculated by the control unit 10, and the insertion loss, the reflection attenuation amount, the position of the defective part and its degree are calculated. Measure. [Selection diagram] Fig. 1

Description

The present invention relates to an optical device inspection machine that measures insertion loss and reflection attenuation of an optical device and inspects cracks, disconnections, etc. of the optical device.

Conventionally, in optical devices such as optical fibers and optical connectors, insertion loss and reflection attenuation have been measured as basic characteristics, and they are described as basic specifications in their product catalogs. In addition, optical devices are inspected for defects due to disconnection, cracks, etc. at the time of shipment or at the time of periodic inspections, and are used for quality assurance and failure diagnosis.

As is generally widely known, individual devices are used for insertion loss measurement, reflection attenuation measurement, and defect inspection such as disconnection and cracking. In the measurement of insertion loss, a light source such as a laser beam corresponding to the optical device to be measured and a light receiving device such as an optical power meter are used. In the measurement of the reflection attenuation amount, a light source such as a laser beam, an optical coupler, and a light receiving device such as an optical power meter according to the optical device to be measured are used. For example, an optical time domain reflectometer (OTDR) is used to inspect defects due to disconnection or cracks in optical devices, measure the position and intensity of reflected light, and then determine the location and location of the defect. The degree is estimated.

Since it is complicated to prepare members and devices for each measurement item in this way, it has been proposed to use these devices for measurement. For example, a dummy fiber that increases the optical path length is connected to the optical pulse tester to prevent the connection point between the optical device and the optical pulse tester from becoming near-end reflection when viewed from the optical pulse tester, and the optical device. To be able to measure the amount of reflection attenuation of. Further, there is also a proposal to use the light source of the optical pulse tester as a light source for measuring the insertion loss. In this insertion loss measurement method, first, an optical power meter is connected to the optical output of the optical pulse tester via a measurement optical cord, and the optical output of the light source of the optical pulse tester is measured with the optical power meter to be a reference value. And. Next, an optical device to be measured is connected between the optical cord for measurement and the optical power meter, and the optical output of the optical pulse tester is similarly measured by the optical power meter and used as a measured value. By subtracting the measured value from the above reference value, the insertion loss value of the optical device is obtained.

Patent Document 1 proposes an improved optical fiber inspection apparatus and method for inspection of optical fibers based on the above-mentioned method for measuring insertion loss. According to this optical fiber inspection device and method, an optical fiber inspection device that measures the optical power of the measured light that arrives from the light source device via the optical fiber and calculates the amount of optical loss of the optical fiber based on the optical power. Based on the amount of optical loss calculated by this optical fiber inspection device, it is possible to confirm the continuity of the optical fiber to be inspected and search for breakage points, and quantitatively determine the optical loss regardless of the work environment or individual differences. It is disclosed that it can be inspected.

In an optical fiber inspection device that utilizes such optical loss, when the optical fiber cable to be inspected is connected via an optical device such as an optical connector, the optical axis of the optical device and the optical fiber are displaced from each other. It is also performed to measure the optical loss generated by the optical device and detect an optical device having an axis misalignment defect.

Japanese Unexamined Patent Publication No. 2008-116789

In this way, for measurement of insertion loss of optical devices, measurement of reflection attenuation, inspection of defects caused by disconnection, cracks, etc., appropriate light source devices, optical couplers, optical power meters, optical pulse testers, etc. corresponding to the optical devices are used. It is carried out in combination as appropriate, or a dedicated device is used for each. Therefore, each time the measurement item is changed, the optical equipment and optical members used in combination are changed, the connection method with the optical device to be measured is also changed, or the target optical device is connected to a dedicated device. It must be fixed and measured and inspected. Increasing the number of connections / disconnections between an optical device and an optical device, an optical member, and a measuring device causes a problem that the measurement work becomes complicated and takes a lot of time.

Further, even if an optical pulse tester is used to simultaneously measure the amount of reflection attenuation of an optical device and defects such as disconnection and cracks, it may be difficult to clearly distinguish the reflections from both points. For example, when the connection point between the optical device and the optical pulse tester is near-end reflection when viewed from the optical pulse tester, the optical path length is usually increased by a dummy fiber as described above, and the optical pulse tester is inside the optical pulse tester. The reflection attenuation amount is measured so that the connection point between the optical device and the optical pulse tester can be distinguished from the reflection point. At this time, if the connection point between the optical device and the optical pulse tester is extremely close to the part where the optical device is to be inspected for disconnection or cracks in terms of optical path length, in order to distinguish the reflection from both points. , An extremely short optical pulse must be output from the light source in the optical pulse tester.

However, since extremely short optical pulses are severely attenuated with respect to the transmission distance, the attenuation is large when passing through the long optical path of the dummy fiber, and even the weak reflected light from the connection point between the optical device and the optical pulse tester is emitted as light. Even if it can be distinguished from the reflected light from the part where the device is to be inspected for disconnection or cracks, it can only measure the reflected position, and the weak reflected light amount, that is, the reflected attenuation amount, is quantitatively measured with high accuracy. The problem is that it is extremely difficult.

Furthermore, the amount of reflected light from the part of the optical device to be inspected for disconnection or cracks that is being measured at the same time is also weak, so the reflected light amount should be measured quantitatively only by measuring the reflected position. There is also the problem that it is difficult. In particular, in the state immediately after a disconnection or crack occurs in the optical device, the locations of the disconnection or crack are often in close contact with each other, and the reflected light amount becomes even weaker. Therefore, the reflected position is detected and the reflected light amount is measured. Can be difficult together.

An object of the present invention is to solve the above-mentioned problems, and once the optical device is attached, the insertion loss measurement, the reflection attenuation measurement, and the inspection of disconnection and cracks are collectively performed without removing or reattaching the optical device. The purpose is to provide an optical device inspection machine that can be carried out.

The optical device inspection machine according to the present invention for achieving the above object is a light source composed of an SLD, a beam splitter that branches light from the light source into transmitted measurement light and reflected reference light, and the reference light. A reference mirror having an optical path length variable mechanism capable of adjusting the optical path length, the measurement light reflected by the beam splitter, and a first light that receives the reference light reflected by the reference mirror and transmitted through the beam splitter. Control connected to the measuring instrument, the second optical measuring instrument that receives the measurement light transmitted through the beam splitter, the light source, the reference mirror, the first optical measuring instrument, and the second optical measuring instrument. A connection portion is provided inside the housing, and is further separated from a connection portion which is connected to the outside of the housing and is arranged at the optical path destination of the measurement light transmitted through the beam splitter on the same optical axis of the connection portion. The second optical measuring device is provided with a transmitted light input unit, and receives the measurement light incident on the housing from the transmitted light input unit, and the connection unit and the transmitted light input unit are connected to each other. An optical device, which is an object to be measured, is arranged between them, and the control unit uses the measurement light reflected by the connection point between the connection unit and the object to be measured and reflected by the beam splitter, and the reference mirror. By receiving the interference light from the reference light that has been reflected and passed through the beam splitter with the first optical measuring device, the amount of reflection attenuation of the measurement object is measured, and the defective portion of the measurement object is measured. By receiving the interference light of the measurement light reflected by the beam splitter and the reference light reflected by the reference mirror and transmitted through the beam splitter by the first optical measuring instrument. The measurement is performed from the amount of light received by the second optical measuring instrument and the amount of light emitted from the light source after detecting the defective portion and transmitting the object to be measured without being reflected by the defective portion. An optical device inspection machine that measures the insertion loss of an object, wherein the measurement object is an optical device of any one of an optical connector, various optical filters, a beam splitter, an optical coupler, an optical switch, and an optical circulator. The insertion loss value of the measurement object is the amount of light transmitted through the measurement object and received by the second optical measuring device, the amount of light emitted from the light source, and the insertion loss of the measurement object itself. It is characterized in that it is calculated based on a calibration line showing the relationship between the light and the measured value of the insertion loss including the loss of the inspection machine itself and the influence of the machine difference.
The optical device inspection machine according to the present invention has a light source made of SLD, a beam splitter that branches light from the light source into transmitted measurement light and reflected reference light, and an optical path whose optical path length of the reference light can be adjusted. a reference mirror having a length variable mechanism, wherein the measuring light reflected by the beam splitter, and reflected by the reference mirror, and a light measuring device for receiving the reference light transmitted through the beam splitter, said with the reference light beam A shutter for closing and opening the interference light due to the measurement light reflected by the splitter, the light source, the reference mirror, the optical measuring instrument, and a control unit connected to the shutter are provided in the housing, and the beam splitter and the beam splitter are provided. The shutter and the half mirror are sequentially arranged between the optical measuring instruments from the beam splitter side, and further arranged at the optical path destination of the measured light that is connected to the outside of the housing and has passed through the beam splitter. The optical measuring device includes the connected portion and the transmitted light input portion provided apart from each other on the same optical axis of the connecting portion, and the optical measuring instrument receives the measured light incident on the housing from the transmitted light input portion. The light is received through the half mirror, an optical device to be measured is arranged between the connection unit and the transmitted light input unit, and the control unit opens the shutter and connects the light device. The light is the interference light of the measurement light reflected by the connection point between the unit and the measurement object and reflected by the beam splitter and the reference light reflected by the reference mirror and transmitted through the beam splitter. By receiving light with the measuring instrument, the amount of reflection attenuation of the object to be measured is measured, the shutter is opened, the measured light reflected by the defective portion of the object to be measured, and the measured light reflected by the beam splitter. The defective portion is detected by receiving the interference light from the reference light reflected by the reference mirror and transmitted through the beam splitter by the optical measuring device, the shutter is closed, and the measurement object is measured. from the quantity of light received by the optical measuring device passes through without being reflected by the defective portion, the amount of light emitted from the light source, and measuring the insertion loss of the measurement object ..

According to the optical device inspection machine according to the present invention, once the optical device is attached to the connection portion, the insertion loss and the reflection attenuation of the optical device can be measured without disconnection or reattachment, and the optical device can be cracked or disconnected. It is possible to carry out such inspections collectively without affecting each other's measurements or inspection results, and it is possible to significantly reduce the labor and time required for measurements and inspections.

In addition, space can be saved by sharing a part of the optical members used for measuring insertion loss and reflection attenuation and inspecting cracks, disconnections, etc., and by unifying the light source to be used in particular. , Can be manufactured at low cost.

It is a block diagram of the optical device inspection machine of Example 1. FIG. It is a graph of the spectral distribution of a light source. It is explanatory drawing of the connection state of an optical device. It is a graph of the relationship between the optical path length difference and the intensity of the interference light. It is a graph of the relationship between the distance of the connection point and the defective part of an optical device, and the strength of a beat signal. It is a block diagram for obtaining the calibration line of the insertion loss. It is a graph of the calibration line used in the measurement of the insertion loss. It is a block diagram for obtaining the calibration line of the reflection attenuation amount and the disconnection inspection. It is a graph of the calibration line used for the measurement of the reflection attenuation amount and the disconnection inspection. It is a block diagram of the optical device inspection machine of Example 2.

The present invention will be described in detail with reference to the illustrated examples.

FIG. 1 is a block configuration diagram of the optical device inspection machine 1 of the first embodiment, and the optical device C, which is an object to be measured, is connected to the optical device inspection machine 1. A wide variety of optical devices C can be applied. For example, a single measured connector having an optical path inside, this measured connector, an optical fiber cable connected to this measured connector, and a pair of measured connectors. In particular, optical fibers connecting these pairs of connectors under test, various optical filters such as TFF (Thin Film Filter) modules, beam splitters, optical couplers, optical switches, optical circulators, etc. can be applied. It is not limited to these.

The optical device inspection machine 1 emits a wide band and low coherence light L in the housing 2, a light source 3 composed of, for example, an SLD (Superhaving Diode), a measurement light L1 transmitted through the light L, and a reflected reference light. A beam splitter 4 that divides the amount of light into L2 evenly, a reference mirror 5 having an optical path length variable mechanism that can adjust the optical path length of the reference light L2, a connection point between the optical device C, and a disconnection or crack in the optical device C. It is provided with a first optical measuring instrument 6 that receives the measurement light L1'reflected at a defective portion such as the above and the reference light L2'reflected by the reference mirror 5 via the beam splitter 4.

Further, the optical device inspection machine 1 is further in contact with the connection portion 7 connected to the outside of the housing 2 and the other end of the optical device C provided separately on the same optical axis of the connection portion 7. It includes an input unit 8 and a second optical measuring device 9 that receives the measurement light L1 incident on the housing 2 from the transmitted light input unit 8.

The connection portion 7 arranged at the optical path outside the housing 2 of the measurement light L1 transmitted through the beam splitter 4 is connected with the optical axis aligned with one end of the optical device C as the measurement target. It should be noted that each member constituting the optical device inspection machine 1 is not necessarily limited to being provided on the inner and outer surfaces of the housing 2, and may be provided on a base such as an optical surface plate instead of the housing 2, for example. good.

Further, a control unit 10 is connected to the light source 3, the reference mirror 5, the first optical measuring instrument 6, and the second optical measuring instrument 9, and the control unit 10 controls the operation and the like of these members. There is. Further, the control unit 10 calculates the measured values of the first optical measuring instrument 6 and the second optical measuring instrument 9, quantifies the insertion loss, the reflection attenuation amount, the position and the degree of the defective portion, and is not shown. Output to display means and storage means. These display means and storage means may be a built-in type PC arranged in the housing 2, or may be a notebook PC or the like connected to the outside.

The control unit 10 stores a plurality of calibration lines to be described later, and calculates the insertion loss, the reflection attenuation amount, and the reflected light amount from the measured values by the first optical measuring instrument 6 and the second optical measuring instrument 9 based on the calibration lines. It has a function to calculate.

FIG. 2 is a graph of the spectral distribution of the light source 3. While the LD (Laser Diode) has a spectral distribution of only a few nm, typically ± 5 nm, the light source 3 consisting of, for example, an SLD is a broadband one having a spectral distribution of several tens of nm, preferably ± 40 nm. .. The light source 3 has a low coherence property in which the coherent length is shorter than that of the LD, and can emit high-intensity and phase-aligned light like the LD, and can be used for measurement using optical interference. It is possible.

Further, in order to maintain the output stability of the light L with respect to the temperature, the light source 3 is equipped with a temperature control means using a Pelche element or the like. Similarly, the second optical measuring instrument 9 is also equipped with a temperature control means using a Pelche element or the like in order to stabilize the light receiving characteristics.

The reference mirror 5 includes an optical path length variable mechanism that can move to an arbitrary position along the reference optical path of the reference light L2. For example, a rotary reflector can be used for the optical path length variable mechanism of this reference optical path. The optical path length variable range of this rotary reflector is secured to be equal to or longer than the optical path length within the range for inspecting the disconnection or crack of the optical device C. For example, if the optical path length of the optical device is 20 mm, the variable range of 20 mm is secured. In addition, a mechanism with a radius of 20 mm and a rotation speed of about 1.1 rotations / second is adopted.

Since the connection portion 7 only needs to be able to transmit the measurement light L1 with the optical axis aligned with the optical device C, it is possible to adopt a wide variety of structures depending on the form of the optical device C. For example, if the optical device C has a short optical path length such as an optical connector as shown in FIG. 1, the connection portion 7 is attached to the tip of the optical fiber 7a that transmits the measurement light L1 to the vicinity of the optical device C. It is suitable to have a connection terminal 7b attached to one end of the optical device C so that the optical axis can be aligned and connected. If the optical device C has a long optical path length such as an optical fiber having optical connectors attached to both ends, the connection portion 7 may be composed of only the connection terminal 7b.

The transmitted light input unit 8 has an aperture sufficiently larger than the beam diameter of the measurement light L1 emitted from the other end of the optical device C while spreading at a predetermined aperture angle, and is particularly strictly aligned with the optical axis of the optical device C. It suffices if it is in contact with the other end of the optical device C. As a method of connecting the transmitted light input unit 8 and the optical device, for example, there is also a method of providing a fixed hole in the transmitted light input unit 8 and inserting the other end of the optical device into the fixed hole to fix and connect the device.

Similarly, since the light receiving surface of the second optical measuring instrument 9 is sufficiently larger than the beam diameter of the measurement light L1 emitted from the other end of the optical device C while spreading at a predetermined aperture angle, the optical device C and the second optical device C have a second light receiving surface. It is not necessary to arrange the optical axes of the optical measuring instrument 9 so as to be exactly aligned with each other, and there is no problem even if the optical measuring instrument 9 is slightly separated from the transmitted light input unit 8.

An optical fiber can be used for each optical path of the light L emitted from the light source 3, and a fiber coupler can be used instead of the beam splitter 4 to straighten and branch the light L. Further, a lens optical system, a polarization beam splitter, a 1/4 wave plate, etc. may be further used in the optical path of the actual optical device inspection machine 1, but these are known optical means. , The explanation is omitted.

The light L emitted from the light source 3 is branched at the beam splitter 4, and the measurement light L1 traveling straight through the beam splitter 4 is transmitted to the optical device C through the connection portion 7. On the other hand, the light L reflected by the beam splitter 4 becomes the reference light L2 and is transmitted to the reference mirror 5.

When the measurement light L1 is transmitted to the optical device C, if the optical device C is a good product, most of the light passes through the optical device C to become the transmitted measurement light LT1 and is received by the second optical measuring instrument 9. .. A part of the measurement light L1 is reflected at the connection point between the connection portion 7 and the optical device C to become the reflection measurement light LR1, returns from the connection portion 7, is reflected by the beam splitter 4, and is received by the first optical measuring instrument 6. ..

Further, if there is a defective portion C1 such as a disconnection or a crack in the optical device C, the measurement light L1 is partially reflected even at the defective portion C1 to become the defective reflection measurement light LF1, which is reflected by the beam splitter 4 and is the first. The light is received by the optical measuring instrument 6. On the other hand, the reference light L2 is reflected by the reference mirror 5 to become the reference light L2', which passes through the beam splitter 4 and is received by the first optical measuring instrument 6.

For example, from the light source 3 made of SLD, low coherent and phase-aligned light L having a wavelength of 1310 ± 40 nm is emitted, and the reflected light including from the connection point between the connection portion 7 and the optical device to the defective point in the optical device C is emitted. The measurement range is, for example, 0 to 20 mm, and the measured decomposition length of the reflection position is, for example, 1.25 μm. Correspondingly, the variable range of the optical path length variable mechanism of the reference mirror 5 for adjusting the optical path length of the reference light L2 is also set to be equivalent to, for example, 20 mm.

When measuring the insertion loss of the optical device C, measuring the amount of reflection attenuation, and inspecting defective parts such as disconnections and cracks, first, one end of the optical device C to be measured is connected to the connection portion 7 of the optical device inspection machine 1. The other end is arranged so as to be in contact with the transmitted light input unit 8. Then, when a predetermined amount of light L suitable for the insertion loss measurement is emitted from the light source 3, the light L is branched into the measurement light L1 to the optical device C and the reference light L2 to the reference mirror 5 by the beam splitter 4. ..

First, the measurement light L1 reaches the optical device C through the connection portion 7. Most of the measurement light L1 passes through the optical device C, is attenuated by the insertion loss of the optical device C, enters the housing 2 from the transmitted light input unit 8, and is received by the second optical measuring instrument 9. Ru. The light receiving amount of the second optical measuring device 9 is input to the control unit 10, and the control unit 10 subtracts the light receiving amount from the predetermined light amount to calculate the measured value of the insertion loss.

In addition to the insertion loss of the optical device C itself, the measured value of the insertion loss includes the loss of the optical device inspection machine 1 itself such as the beam splitter 4 and the connection portion 7. Further, there are differences in the loss of the optical device inspection machine 1 itself and the light receiving characteristics of the second optical measuring instrument 9, and the influence thereof is also included in the measured value of the insertion loss. ing. Since the control unit 10 stores the calibration curve showing the relationship between the insertion loss IL of the optical device C itself and the measured value of the insertion loss including the loss of the optical device inspection machine 1 itself and the influence of the machine difference, this is stored. According to the calibration curve, the insertion loss IL of the optical device C is calculated from the measured value of the insertion loss. A method for acquiring a calibration curve representing the relationship between the insertion loss IL of the optical device C itself stored in the control unit 10 and the measured value of the insertion loss will be described later.

Next, the light L is emitted from the light source 3 by changing the amount of light to a predetermined amount suitable for measuring the amount of reflection attenuation and inspecting defective parts such as disconnection and cracks. Similarly, the light L is split into the measurement light L1 and the reference light L2 by the beam splitter 4, and the measurement light L1 reaches the optical device C through the connection portion 7.

FIG. 3 is an explanatory diagram schematically showing the connection state between the connection unit 7 and the optical device C. For example, the case where there is an axial deviation at the connection point between the connection terminal 7b of the connection portion 7 and the optical device C, and the defective portion C1 of the crack exists in the portion 5 mm inside the optical device C from this connection point is shown. There is. Subsequent operations related to the amount of reflection attenuation and the inspection of defective parts such as disconnection and cracks will be described on the premise that the optical device C is in the state shown in FIG.

A part of the measurement light L1 is reflected more strongly than usual at the connection point between the connection portion 7 and the optical device C due to a slight misalignment, becomes the reflection measurement light LR1 and returns to the connection portion 7, and is a beam. It is reflected by the splitter 4 and received by the first optical measuring instrument 6. At this time, the reference light L2 is reflected by the reference mirror 5 to become the reference light L2', passes through the beam splitter 4, and is received by the first optical measuring instrument 6 at the same time as the reflection measurement light LR1. Therefore, the first optical measuring instrument 6 receives the reflected interference light LIR, which is the interference light between the reflection measurement light LR1 and the reference light L2'.

FIG. 4 is a graph showing the relationship between the intensity of the reflected interference light LIR received by the first optical measuring device 6 and the optical path length difference between the reflected measurement light LR1 and the reference light L2'. When the optical path lengths of the reflection measurement light LR1 and the reference light L2'are matched, the intensity of the reflected interference light LIR is maximized. Therefore, using this characteristic, the control unit 10 moves the reference mirror 5 along the optical path to change the optical path length of the reference light L2', and adjusts the intensity of the reflected interference light LIR to the maximum. It matches the optical path length of the reflection measurement light LR1. At this time, if the control unit 10 grasps the moving distance of the reference mirror 5, the position of the connection point between the connection unit 7 and the optical device C corresponding to the optical path length of the reflection measurement light LR1 can be detected. Further, at this time, since the intensity of the reflected interference light LIR can be maximized, an extremely strong peak-shaped beat signal is received by the first optical measuring instrument 6.

FIG. 5 shows a peak-shaped beat signal received by the first optical measuring instrument 6, and the horizontal axis is the distance (position) where the beat signal is generated with the connection point between the connection portion 7 and the optical device C as a zero point. The vertical axis represents the strength of the beat signal. As shown in FIG. 5, the beat signal er1 caused by the reflection measurement light LR1 from the connection point between the connection portion 7 and the optical device C not only has a joint surface at the connection portion but also has a slight axial deviation. It appears as a beat with extremely high intensity at a distance of 0.

On the other hand, the measurement light L1 that has passed through the connection point between the connection portion 7 and the optical device C reaches the inside of the optical device C, and if there is a defective part such as a disconnection or a crack in the optical device C, it is reflected there and defectively reflected. It becomes the measurement light LF1 and returns to the connection portion 7, is reflected by the beam splitter 4, and is received by the first optical measuring device 6. As shown in FIG. 3, the currently connected optical device C has a crack defective portion C1 at a portion 5 mm from the connection point between the connecting portion 7 and the optical device C, so that the defective reflection measurement light is reflected there. LF1 is generated.

At this time, the reference light L2'is received by the first optical measuring instrument 6 at the same time as the defective reflection measurement light LF1 as described above. Therefore, the first optical measuring instrument 6 receives the defective reflection interference light LIF, which is the interference light between the defective reflection measurement light LF1 and the reference light L2'.

Similarly, the intensity of the poor reflection interference light LIF has a relationship as shown in FIG. 4 with respect to the optical path length difference between the bad reflection measurement light LF1 and the reference light L2'. Therefore, the control unit 10 moves the reference mirror 5 along the optical path to change the optical path length of the reference light L2', adjusts the intensity of the defective reflection interference light LIF to the maximum, and adjusts the intensity of the defective reflection interference light LF1 to the maximum. Match with the optical path length. At this time, if the control unit 10 grasps the moving distance of the reference mirror 5, the position of the defective portion C1 of the optical device C corresponding to the optical path length of the defective reflection measurement light LF1 can be detected. Further, at this time, since the intensity of the defective reflection interference light LIF can be maximized, the beat signal caused by the defective portion C1 located 5 mm inside the optical device C from the connection point between the connection portion 7 and the optical device C. As shown in FIG. 5, ef1 appears as a high-intensity beat at a distance of 5 mm.

Since the connection point between the connection unit 7 and the optical device C has a clear axis deviation as shown in FIG. 3, the beat signal er1 by the connection point between the connection unit 7 and the optical device C is as shown in FIG. It has a larger peak value than the beat signal ef1 due to the defective portion C1. However, in general, the magnitude relationship between the reflection measurement light LR1 from the connection point between the connection portion 7 and the optical device C and the defective reflection measurement light LF1 due to the disconnection or crack of the optical device C is the axis deviation or disconnection. It changes appropriately depending on the degree of cracks and the like, and the beat signals er1 and ef1 shown in FIG. 5 are only examples.

By moving the reference mirror 5 in this way, the optical path length of the reference light L2'is changed to the reflection measurement light LR1 or LF1 from the connection point between the connection portion 7 and the optical device C or the defective portion C1 in the optical device C. When the optical path lengths of the above are matched, as shown in FIG. 5, the first optical measuring instrument 6 can receive the peak-shaped beat signals er1 and ef1 due to interference. Since the intensity of this peak-shaped beat signal is significantly higher than that of the reflected light from a position where there is no connection between optical members, disconnection, cracks, etc., when a beat signal is obtained, the connection points between the optical members are set. It is possible to easily detect that there is a defect such as a disconnection or a crack in the optical device C and specify the position thereof.

Further, even if there are a plurality of connection points between optical members and defective points in the optical device C and they are extremely close to each other in a distance, optical interference is used, so that the reflected light from each point is used. Can be detected separately. If only the position of the reflection point is detected, it can be detected with the same order as the wavelength of the light L, for example, with a resolution of 1.0 μm, and if the intensity of the reflected light is measured, 10 to 10 of the wavelength of the light L. It can be measured with a resolution of 20 times, for example, 20 μm. Furthermore, since this measurement is based on highly sensitive optical interference, the light intensity of the beat signal is remarkably high even if the hidden wire is only weakly reflected light in the optical device C, so the position of the hidden wire is determined. It can also be detected.

If no defective part in the optical device C is found by detecting the reflected light using this optical interference, it can be determined that there is no defect in the optical device C, but if a defective part is detected, it can be determined. Furthermore, it is necessary to inspect the degree of the defect. By measuring the intensity of the defective reflection interference light LIF caused by the defective reflection measurement light LF1 from the defective portion of the optical device C obtained by the first optical measuring instrument 6, the disconnection, cracks, etc. in the optical device C can be measured. The state of failure can be inferred to some extent.

Similarly, if the position of the connection point between the connection unit 7 and the optical device C can be specified by detecting the reflected light using this optical interference, it is caused by the reflection measurement light LR1 from the connection point between the connection unit 7 and the optical device C. By measuring the intensity of the reflected interference light LIR, the amount of reflection attenuation of the optical device C can be quantified.

However, if these interference lights LIR and LIF are simply received by the first optical measuring instrument 6 and the light intensity is immediately quantified, the amount of reflection attenuation of the optical device C and the disconnection / cracking that occurs inside are generated. It is not possible to quantify the degree of defects such as. This is because the intensity of the beat signal simply obtained from the amount of light received by the first optical measuring instrument 6 is the first, even if the optical intensity of the interference light incident on the first optical measuring instrument 6 is constant. This is because the values are greatly affected by the individual characteristics of the optical measuring instrument 6 itself and the amplification circuit (not shown) connected to the optical measuring instrument 6 itself, and the numerical values differ for each optical device inspection machine 1. Further, the strength of the beat signal simply obtained by the first optical measuring instrument 6 is such that the characteristics of the optical members such as the beam splitter 4, the reference mirror 5, and the connection portion 7 differ depending on the individual optical device inspection machine 1. In other words, it goes without saying that the influence of the machine error is also included.

Therefore, the intensities of the interference light LIR and LIF caused by the reflected light generated by the connection point between the connection portion 7 and the optical device C and the internal disconnection / crack, etc. are universal without any difference between the individual optical device inspection machines 1. In order to quantify the light, the light receiving characteristics of the first optical measuring instrument 6, including each optical member and the amplification circuit, are calibrated using a reference optical device or optical system. Then, the measured values of the interference light received by the first optical measuring instrument 6 and the intensity of the interference light obtained by removing the machine difference of the optical device inspection machine 1 such as the light receiving characteristics of the first optical measuring instrument 6 from them. A calibration line representing the relationship between the above is acquired and stored in the control unit 10 for each optical device inspection machine 1.

When the individual optical device inspection machine 1 actually measures the reflection attenuation of the optical device C and detects defects such as disconnection and cracks, the interference light LIR and LIF received by the first optical measuring device 6 The measured value of the intensity of the above is calibrated by this calibration line, and the amount of reflected light reflected by the optical device C and the amount of reflected light due to defects such as disconnection and cracks are calculated.

As described above, in order to measure the amount of reflected light due to defects such as insertion loss, reflection attenuation, disconnection / crack, etc. by the optical device inspection machine 1 with high accuracy, the first optical measuring instrument 6 including each optical member and the first optical measuring instrument 6 and the first Calibrate so that there is no difference between the individual optical device inspection machines 1 due to the variation in the light receiving characteristics of the optical measuring device 9 of 2.

FIG. 6 shows individual optical devices in order to obtain a calibration line used when calculating the insertion loss value ILC of the optical device C from the measured value ILMC of the insertion loss of the optical device C received by the second optical measuring instrument 9. It is a block diagram in the case of performing the calibration work for each inspection machine 1. In place of the optical device C which is the measurement target, the calibration reference optical device C0 and the calibration optical attenuator G which are the calibration reference objects are sequentially connected to the connection portion 7 of the optical device inspection machine 1 which is the calibration target. Connecting.

As the calibration reference optical device C0, a light source having the same characteristics as the light source 3 whose insertion loss value IL0 has been measured in advance is used. The insertion loss value IL0 of the calibration reference optical device C0 may be approximately the same as the insertion loss value ILC of the optical device C to be measured, but preferably a slightly smaller value is suitable for improving the calibration accuracy. There is. Further, the calibration optical attenuator G is calibrated in advance by a light source having the same characteristics as the light source 3 so that the set value of the attenuation amount matches the actual light attenuation amount, and the actual light with respect to the set value of the attenuation amount. Use one that guarantees the linearity of the attenuation. That is, a calibration reference optical device C0 and a calibration optical attenuator G whose loss amount (attenuation amount) when the light emitted from the light source 3 is transmitted are known are used.

At the time of calibration, a predetermined amount of light L is emitted from the light source 3 as in the case of measuring the insertion loss. The light L is split into the measurement light L1 and the reference light L2 by the beam splitter 4, but only the measurement light L1 is used for calibration. The measurement light L1 passes through the connection unit 7, the calibration reference light device C0, and the calibration light attenuator G in order to become the transmission measurement light LT1, enters the housing 2 from the transmission light input unit 8, and performs the second light measurement. Light is received by the vessel 9.

At this time, the amount of optical attenuation of the calibration optical attenuator G is set to zero, and the transmission measurement light LT1 receives a loss by the amount of the insertion loss value IL0 of the calibration reference optical device C0, and the second optical measuring instrument 9 To receive light. The control unit 10 subtracts the light receiving amount of the second light measuring device 9 at this time from the predetermined light amount of the light source 3 to calculate the measured value ILM0 of the insertion loss. Subsequently, the light attenuation of the calibration optical attenuator G is set to a predetermined value, for example, several dB, and the transmission measurement light LT1 is (insertion loss value IL0 + attenuation number dB of the calibration light attenuator G) = IL1. It receives a loss by the amount and receives light from the second optical measuring instrument 9. The control unit 10 subtracts the light receiving amount of the second light measuring device 9 at this time from the predetermined light amount of the light source 3 to calculate the measured value ILM1 of the insertion loss.

FIG. 7 is a calibration line for calculating the insertion loss, and the insertion loss measured by the second optical measuring instrument 9 described above is set by the calibration reference optical device C0 and the calibration optical attenuator G. It is plotted against the loss IL and a calibration line is drawn to approximate the plot. The measured value of insertion loss ILM0 is plotted at the point of insertion loss value IL0, ILM1 is plotted at the point of insertion loss value (IL0 + number dB) = IL1, and a calibration line passing through the two points is drawn. This calibration line is the measured value of the insertion loss including the machine difference due to the optical member of each optical device inspection machine 1 and the characteristic variation of the second optical measuring device 9, and the measurement object actually attached to the connection portion 7. It shows the relationship with the insertion loss value of.

If the data of this calibration line is stored in the control unit 10, when the insertion loss of the optical device C is measured by the above procedure, the calibration line is used and measured by the second optical measuring instrument 9. The insertion loss value ILC of the optical device C can be obtained from the measured value ILMC of the insertion loss. The obtained insertion loss value ILC of the optical device C is the insertion loss of the optical device C itself, which eliminates the machine difference due to the variation in the characteristics of the optical member of the individual optical device inspection machine 1 and the second optical measuring instrument 9. It is possible to measure the loss with high accuracy.

In order to improve the accuracy of the calibration line, the setting of the optical attenuation of the calibration optical attenuator G is further changed to perform calibration, and the measured value of the insertion loss at this time is plotted against the set insertion loss. It is also possible to increase the number of plots and then draw a calibration line that approximates many plots.

FIG. 8 shows a calibration line used when calculating the reflected attenuation amount of the optical device C or the reflected light amount due to the defective portion from the measured values of the reflected interference light LIR or the defective reflected interference light LIF received by the first optical measuring device 6. It is a block diagram in the case of performing the calibration work for each optical device inspection machine 1 in order to obtain. In the connection portion 7 of the optical device inspection machine 1 to be calibrated, instead of the optical device C which is the measurement object, the calibration reference optical device C0 which is the calibration reference object as the optical system for calibration and the calibration light The attenuator G and the reflection mirror M are connected in sequence.

As the calibration reference optical device C0, a light source having the same characteristics as the light source 3 whose insertion loss value IL0 and reflection attenuation RL0 have been measured in advance is used. The calibration light attenuator G is calibrated in advance by a light source having the same characteristics as the light source 3 so that the set value of the attenuation amount matches the actual light attenuation amount, and the linearity of the actual light attenuation amount with respect to the set value of the attenuation amount. Use the one that is guaranteed. That is, the amount of reflected light when the light emitted from the light source having the same characteristics as the light source 3 reciprocates back and forth between the calibration reference light device C0, the calibration optical attenuator G, and the reflection mirror M is known, and is used for calibration. The calibration reference optical device C0, the calibration light attenuator G, and the reflection mirror M are set in advance so that the intensity of the reflected light amount can be arbitrarily set by changing the setting value of the light attenuation amount of the light attenuator G. It shall be calibrated.

When calibrating, the light source 3 is changed to a predetermined amount of light suitable for measuring the amount of reflection attenuation and inspecting defective parts such as disconnections and cracks, and emits light L. The light L is branched into the measurement light L1 and the reference light L2 by the beam splitter 4, and the measurement light L1 sequentially reaches the reflection mirror M through the connection portion 7, the calibration reference light device C0, and the calibration light attenuator G. .. The measurement light L1 is reflected by the reflection mirror M to become the reflection measurement light LR1, returns through the calibration optical attenuator G, the calibration reference light device C0, and the connection portion 7, and is reflected by the beam splitter 4 to be the first. The light is received by the optical measuring instrument 6.

On the other hand, the reference light L2 is reflected by the reference mirror 5 to become the reference light L2', passes through the beam splitter 4, and is received by the first optical measuring instrument 6 at the same time as the reflection measurement light LR1. Therefore, the first optical measuring instrument 6 receives the reflected interference light LIR, which is the interference light between the reflection measurement light LR1 and the reference light L2'.

At this time, light having the same characteristics as the light source 3 passes through the calibration reference light device C0 and the calibration light attenuator G and is reflected by the reflection mirror M, and the calibration light attenuator G and the calibration reference light device C0 are used again. The amount of light attenuation of the calibration light attenuator G is set so that the reflected light that has passed through and returned has a predetermined intensity such as -14.7 dB. This setting of the reflected light intensity of -14.7 dB corresponds to the intensity of the reflected light generated by the interface between the cut surface and the air of a typical optical fiber, and calibrates the reflected attenuation amount and the reflected light amount from the defective point. However, the present invention is not limited to this, and can be arbitrarily set based on the amount of reflection attenuation of the optical device C and the like.

If the light attenuation amount of the calibration optical attenuator G is set in this way, the measurement light L1 reciprocates between the calibration reference optical device C0, the calibration optical attenuator G, and the reflection mirror M, for example, -14. The reflection measurement light LR1 is attenuated according to the setting such as 0.7 dB.

Using the relationship between the light intensity and the optical path length difference shown in FIG. 4, the reference mirror 5 is moved along the optical axis so that the intensity of the reflected interference light LIR by the reflection measurement light LR1 and the reference light L2'is maximized. Then, the reference optical path length up to the reference mirror 5 by the reference light L2 is made to match the measured optical path length up to the reflection mirror M by the measurement light L1.

In this state, the calibration line P is created by using the measured value of the amount of light when the reflected interference light LIR is received by the first optical measuring instrument 6. In FIG. 9, the horizontal axis represents the intensity of the reflected light amount set as described above, and the vertical axis represents the intensity of the measured value of the reflected interference light LIR received by the first optical measuring instrument 6.

In the configuration of FIG. 8, when the light attenuation rate of the optical path reciprocating from the calibration reference optical device C0 through the calibration optical attenuator G and the reflection mirror M, that is, the intensity of the reflected light amount is set to -14.7 dB, reflection is performed. The intensity RM1 of the measured value of the amount of light received by the first optical measuring device 6 for the interference light LIR is plotted on the graph shown in FIG. 9 as the reference point β1. Further, even when the intensity of the reflected light amount is set to, for example, -10 dB, the intensity RM2 of the value measured by the first optical measuring instrument 6 is similarly plotted on the graph shown in FIG. 9 as the reference point β2. A calibration line P is drawn so as to pass through the reference points β1 and β2, and the data of this calibration line is stored in the control unit 10. This calibration line P is actually attached to the connection portion 7 and the intensity of the measured value of the reflected light amount including the machine difference due to the optical member of each optical device inspection machine 1 and the characteristic variation of the first optical measuring device 6. It shows the relationship with the intensity of the amount of reflected light by the object to be measured.

When measuring the amount of reflection attenuation of the optical device C, as shown in FIG. 9, the calibration line P is used from the intensity RLMC of the measured value of the reflected interference light LIR received by the first optical measuring instrument 6. The reflection attenuation amount RLC of the optical device C can be obtained. Similarly, when measuring the amount of reflected light due to defects such as disconnection and cracks in the optical device C, the calibration line is obtained from the intensity RFMC of the measured value of the defective reflected interference light LIF received by the first optical measuring instrument 6. P can be used to determine the intensity RFC of the amount of reflected light due to the defect of the optical device C. The obtained reflection attenuation amount RLC of the optical device C and the intensity RFC of the reflected light amount due to the defect are the light excluding the machine difference due to the variation in the characteristics of the optical member of each optical device inspection machine 1 and the first optical measuring device 6. It is the reflected attenuation amount and the intensity of the reflected light amount of the device C itself, and the reflected attenuation amount can be measured with high accuracy, and by quantifying the intensity of the reflected light amount, the degree of defect can be quantitatively grasped.

By changing the setting of the light attenuation amount of the calibration optical attenuator G in order to improve the accuracy of the calibration line P, the light attenuation device C0 for calibration is reciprocated by the reflection mirror M via the optical attenuator G for calibration. The amount of light attenuation of the optical path, that is, the intensity of the reflected light amount may be set to a smaller value, and similar measurements may be performed for further calibration data acquisition. At this time, the intensity of the measured value of the reflected interference light received by the first optical measuring device 6 is plotted against the intensity of the reflected light amount set to a smaller value, the number of plots is increased, and then many plots are made. It is also possible to improve the calibration accuracy by drawing a calibration line P that approximates.

The optical device inspection machine 1 of the first embodiment includes a second optical measuring instrument 9 as shown in FIG. 1 for measuring the insertion loss of the optical device C, but the first optical measuring instrument 6 is used. It can also be used for measuring the insertion loss, and a configuration in which the second optical measuring instrument 9 is not provided is also possible. FIG. 10 shows the optical device inspection machine 1 of the second embodiment in which only one optical measuring instrument 6'is configured instead of the configuration of the first optical measuring instrument 6 and the second optical measuring instrument 9 of the first embodiment. It is a block diagram of'.

A shutter 11 and a half mirror 12 are sequentially arranged from the beam splitter 4 side along the optical axis between the beam splitter 4 and the optical measuring instrument 6'in the housing 2. The shutter 11 is connected to the control unit 10, and the opening / closing operation can be controlled by the control unit 10. Further, a transmitted light input unit 8 having a circular opening for passing the transmitted measurement light LT1 is provided on the outer surface of the housing 2 facing the half mirror 12. An optical device C, which is an object to be measured, is arranged between the connection unit 7 arranged at the optical path of the measurement light L1 transmitted through the beam splitter 4 and the transmitted light input unit 8.

The half mirror 12 transmits the light incident from the beam splitter 4 side to the optical measuring instrument 6'side, and reflects the transmitted measurement light LT1 incident from the transmitted light input unit 8 to the optical measuring instrument 6'side. Since the configurations of the other members are the same as those in the first embodiment, the description thereof will be omitted.

When measuring the insertion loss of the optical device C, the light L is emitted from the light source 3 and branched into the measurement light L1 and the reference light L2 by the beam splitter 4, but the reference light L2'and the measurement light L1 are reflected. Since the measurement light L1'which is the return light is unnecessary for the measurement, the control unit 10 closes the shutter 11 so that the measurement light L1'and the reference light L2' do not reach the half mirror 12. The measurement light L1 reaches the optical device C through the connection portion 7, becomes a transmission measurement light LT1 attenuated by the insertion loss of the optical device C, enters the housing 2 from the transmission light input unit 8, and is half. It is reflected by the mirror 12 and received by the optical measuring instrument 6'. Since the arithmetic processing by the control unit 10 for the amount of received light is the same as the description of the operation in the above-mentioned insertion loss measurement, the description thereof will be omitted.

When measuring the amount of reflection attenuation of the optical device C and inspecting for defects such as disconnection and cracks, the control unit 10 keeps the shutter 11 open, and the other end of the optical device C is located outside the opening of the transmitted light input unit 8. Leave it to. By doing so, the measurement light L1 that has passed through the optical device C is not reflected by the half mirror 12 and received by the light measuring device 6'.

Since the half mirror 12 transmits the reflection measurement light LR1, the defective reflection measurement light LF1, and the reference light L2'reflected or transmitted through the beam splitter 4, the light measuring instrument 6'transmits the reflection interference light LIR which is the interference light thereof. , Bad reflection interference light LIF is received. Since the arithmetic processing by the control unit 10 for the amount of interference light received is the same as the operation in the above-mentioned reflection attenuation measurement and defect inspection such as disconnection and cracking, the description thereof will be omitted.

Since the optical device inspection machine 1'of the second embodiment is composed of one optical measuring instrument 6', it is possible to further reduce the size and cost as compared with the optical device inspection machine 1 of the first embodiment. can.

In addition, instead of the shutter 11 which is a means for preventing the reference light L2', the reflection measurement light LR1 and the defective reflection measurement light LF1 from reaching the half mirror 12, for example, a moving mechanism for removing the beam splitter 4 from the optical path of the light L is adopted. It is also good. Further, when measuring the amount of reflection attenuation and inspecting defects such as disconnection and cracks, the other end of the optical device C is not positioned outside the opening of the transmitted light input unit 8, but the opening of the transmitted light input unit 8 is opened. A closing mechanism may be provided.

As described above, according to the optical device inspection machines 1 and 1'of this embodiment, once the optical device C, which is the object to be measured, is attached to the connection portion 7, the optical device C is removed or reconnected. It is possible to collectively inspect defects such as insertion loss, reflection attenuation, disconnection and cracks without performing. Further, even if the connection point between the connection portion 7 and the optical device C and the defective portion C1 such as a disconnection or a crack are extremely close to each other, the position where each reflection occurs can be accurately detected. Further, since the control unit 10 stores a calibration line that excludes the variation in the characteristics of the optical member and the optical measuring instrument from the measured value of the amount of light, the calibration line is used to use the calibration line of each optical device inspection machine 1. It is possible to perform high-precision measurement without any machine error every 1'. Therefore, even when only weak reflected light such as a hidden disconnection is generated, it is possible to quantify the intensity of the reflected light caused by the defect and accurately grasp the defective state.

1, 1'Optical device inspection machine 2 Housing 3 Light source 4 Beam splitter 5 Reference mirror 6 First optical measuring instrument 6'Optical measuring instrument 7 Connection part 8 Transmitted light input unit 9 Second optical measuring instrument 10 Control unit 11 Shutter 12 Half Mirror C Optical Device C0 Calibration Reference Optical Device G Calibration Optical Attenuator M Reflection Mirror

Claims (6)

A light source composed of an SLD, a beam splitter that branches light from the light source into transmitted measurement light and reflected reference light, a reference mirror having an optical path length variable mechanism capable of adjusting the optical path length of the reference light, and the above. A first optical measuring instrument that receives the measurement light reflected by the beam splitter and the reference light reflected by the reference mirror and transmitted through the beam splitter, and a first optical measuring device that receives the measurement light transmitted through the beam splitter. The housing is provided with the light measuring device (2), the light source, the reference mirror, the first light measuring device, and a control unit connected to the second light measuring device.
Further, a connection portion connected to the outside of the housing and arranged at the optical path destination of the measurement light transmitted through the beam splitter, and a transmitted light input portion provided apart on the same optical axis of the connection portion. Equipped with
The second optical measuring instrument receives the measured light incident on the housing from the transmitted light input unit, and receives the measured light.
An optical device, which is an object to be measured, is placed between the connection unit and the transmitted light input unit.
The control unit is based on the measurement light reflected by the connection point between the connection unit and the measurement object and reflected by the beam splitter, and the reference light reflected by the reference mirror and transmitted through the beam splitter. By receiving the interference light with the first optical measuring device, the amount of reflection attenuation of the object to be measured is measured.
The first light measurement is performed by measuring the interference light of the measurement light reflected by the defective portion of the measurement object and reflected by the beam splitter and the reference light reflected by the reference mirror and transmitted through the beam splitter. By receiving light with a device, the defective part is detected and
The insertion loss of the object to be measured is calculated from the amount of light received by the second optical measuring device after passing through the object to be measured without being reflected by the defective portion and the amount of light emitted from the light source. It is an optical device inspection machine that measures
The object to be measured is an optical device such as an optical connector, various optical filters, a beam splitter, an optical coupler, an optical switch, or an optical circulator.
The insertion loss value of the measurement object is the amount of light transmitted through the measurement object and received by the second optical measuring device, the amount of light emitted from the light source, and the insertion of the measurement object itself. An optical device inspection machine characterized in that it is calculated based on a calibration line showing the relationship between the loss and the measured value of the insertion loss including the loss of the inspection machine itself and the influence of the machine difference. Instead of the measurement object, a calibration reference object having a known insertion loss value and an optical attenuator calibrated so that the optical attenuation amount matches the set value are sequentially connected to the connection portion. After setting the light attenuation amount of the light attenuator to a predetermined value, the measurement light is passed through the calibration reference object and the light attenuator and received by the second light measuring device, and the second light measuring device receives the measured light. The calibration line obtained by plotting the measurement value of the insertion loss calculated from the amount of light received by the optical measuring instrument with respect to the insertion loss value set by the calibration reference object and the optical attenuator is stored in the control unit. When the measurement value of the insertion loss is calculated from the amount of light transmitted through the measurement object and received by the second optical measuring instrument, the measurement object is measured from the measurement value of the insertion loss based on the calibration line. The optical device inspection machine according to claim 1, wherein the insertion loss value is calculated. A calibration reference object, a light attenuater, and a reflection mirror are sequentially connected to the connection portion in place of the measurement object, and the light reciprocates between the calibration reference object, the light attenuater, and the reflection mirror. The amount of reflected light that has returned is known, and the intensity of the reflected light amount can be arbitrarily set by changing the set value of the light attenuation amount of the light attenuator, and the light attenuation of the light attenuator is calibrated in advance. After changing the set value of the amount and setting the reflected light amount to a predetermined intensity, the measured light is reflected by the reflection mirror through the calibration reference object and the light attenuator, and the calibration reference object and the light attenuation again. The measured value of the interference light received by the first light measuring device of the reflection measurement light attenuated through the device and the interference light with the reference light is plotted against the predetermined intensity of the set reflected light amount. When the amount of reflection attenuation of the object to be measured is measured by storing the calibration line in the control unit and receiving the interference light of the measurement light and the reference light with the first optical measuring device. Or, when the defective portion of the measurement object is detected, the intensity of the reflected light amount corresponding to the measured value of the interference light by the first optical measuring device is calculated and numerically based on the calibration line. The optical device inspection machine according to claim 1, wherein the optical device is inspected. A light source composed of an SLD, a beam splitter that branches light from the light source into transmitted measurement light and reflected reference light, a reference mirror having an optical path length variable mechanism capable of adjusting the optical path length of the reference light, and the above. the measurement light reflected by the beam splitter, and reflected by the reference mirror, interference the a light measuring device for receiving the reference light transmitted through the beam splitter, by the measuring light reflected by the beam splitter with the reference beam A shutter for closing and opening light, the light source, the reference mirror, the optical measuring instrument, and a control unit connected to the shutter are provided in the housing.
The shutter and the half mirror are sequentially arranged from the beam splitter side between the beam splitter and the optical measuring instrument.
Further, a connection portion connected to the outside of the housing and arranged at the optical path destination of the measurement light transmitted through the beam splitter, and a transmitted light input portion provided apart on the same optical axis of the connection portion. Equipped with
The optical measuring instrument receives the measured light incident on the housing from the transmitted light input unit via the half mirror, and receives the measurement light.
An optical device, which is an object to be measured, is placed between the connection unit and the transmitted light input unit.
The control unit opens the shutter, reflects the measurement light reflected by the connection point between the connection unit and the measurement object, and reflects the measurement light reflected by the beam splitter, and reflects the beam by the reference mirror. By receiving the interference light from the reference light transmitted through the splitter with the optical measuring instrument, the amount of reflection attenuation of the object to be measured is measured.
Interference light by the measurement light reflected by the beam splitter and reflected by the beam splitter and the reference light reflected by the reference mirror and transmitted through the beam splitter with the shutter open. Is received by the optical measuring instrument to detect the defective portion.
With the shutter closed, the measurement target is transmitted from the defective portion without being reflected and received by the light measuring device, and the light amount of the light emitted from the light source is used as the measurement target. An optical device inspection machine characterized by measuring the insertion loss of an object. The object to be measured is an optical device such as an optical connector, various optical filters, a beam splitter, an optical coupler, an optical switch, or an optical circulator.
The insertion loss value of the measurement object is the amount of light transmitted through the measurement object and received by the optical measuring instrument, the amount of light emitted from the light source, and the insertion loss of the measurement object itself. The optical device inspection machine according to claim 4, wherein the optical device inspection machine is calculated based on a calibration line showing a relationship between a loss of the inspection machine itself and an insertion loss including the influence of a machine difference, and a calibration line. The object to be measured is one connector to be measured, an optical fiber cable connected to the connector to be measured and the connector to be measured, or an optical fiber cable to connect a pair of connectors to be measured and the pair of connectors to be measured. The optical device inspection machine according to any one of claims 1 to 5, wherein the optical device is any one of the above.

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