JP2657018B2 - Optical Connector Return Loss Measurement System - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an evaluation technique of optical communication parts, especially high precision, an optical connector return loss measurement apparatus for measuring the return loss of the optical connector sensitive.

[0002]

2. Description of the Related Art FIG. 14 shows a conventional optical connector return loss measuring method. In the figure, 01 is a light source, 02 is an optical fiber coupler, 03 is a master optical connector, 04 is an optical connector to be measured, and 05 is an optical power meter. The light source 01 is connected to the first optical fiber 02A of the optical fiber coupler 02, and the emitted light is branched into a second optical fiber 02B and a third optical fiber 02C. The master optical connector 03 is connected to the third optical fiber 02C from which the measurement light is emitted.
Is connected to the master optical connector 03. Further, the measured optical connector 04 is joined to one end of the optical fiber cord 07, and a non-measurement optical connector 08 which is not a measurement target exists at the other end. Agent 06 has been applied. Also, the refractive index matching agent 0 is provided on the end face of the second optical fiber 02B from which the reference light is emitted.
6 is applied. The optical power meter 05 is connected to the remaining fourth optical fiber 02D of the optical fiber connector 02, so that the reflected light from the optical fiber 02C enters the optical power meter 05.

In the method shown in FIG. 14, light emitted from a light source 01 is incident on an optical fiber coupler 02, and one branch light is incident on a master optical connector 03 to which an optical connector 04 to be measured is connected, and the optical connector is connected. Light reflected from the surface is incident on the optical power meter 05. Since the non-measurement optical connector 08 is connected to the measured optical connector 04 via the optical fiber cord 07, the refractive index matching agent 06 is applied to the end face thereof, and the refractive index matching agent 06 is applied to the end face of the second fiber 02B. The rate matching agent 06 is applied to reduce other reflected light as much as possible.

[0004] In this case, ideally, only the reflected light from the optical connector junction between the master optical connector 03 and the measured optical connector 04 enters the optical power meter 05. Thus, by measuring the reflected light power P _s by the optical power meter 05, the reflection attenuation amount of the incident light power P _in to the master optical connector 03 on the basis of the formula shown in the following Expression 1 gamma (dB) Desired.

[0005]

(Equation 1)

[0006]

However, in the conventional measuring method, it is necessary to remove the reflection from the end face of the non-measurement optical connector 08 for each measurement. However, there is a problem that the amount of work increases. Even if an optimum matching agent is selected as the refractive index matching agent 06, the return loss from the end face is 5
Since there is about 0 to 60 dB, the measurement limit of the return loss is governed by this. Further, even when the matching between the matching agent and the refractive index of the end face is perfect, it is difficult to measure 60 dB or more because of the direct detection method. further,
When the reflection from the non-measurement optical connector 08 cannot be removed, or when there is another reflection point in the middle of the optical fiber cord 07, there is a problem that the return loss cannot be measured.

[0007]

2. Description of the Related Art The present invention has been made in view of such prior art, and measures the return loss only at the end face of an optical connector to be measured at a high measurement limit without being affected by other reflection points. It is an object of the present invention to provide a possible optical connector return loss measuring device .

[0008]

According to the present invention, there is provided an optical connector return loss measuring method for measuring the return loss at an optical connector connection between a measured optical connector and a master optical connector. Wherein the light emitted from the light source is branched into a measuring light and a reference light, and the measuring light is guided to an optical connector to be measured connected to the master optical connector. And adjusting the propagation optical path length of the reflected light and the reference light so that they interfere with each other, and measuring the return loss at the optical connector connection portion from the intensity of the interference signal.

An optical connector return loss measuring apparatus according to the present invention is a method for measuring return loss at an optical connector connection between a master optical connector and a measured optical connector, comprising: a light source; An optical splitter connected to the optical splitter to split the light emitted from the light source into the measurement light and the reference light; a master optical connector connected to the measurement light emission side of the optical splitter and joined to the optical connector to be measured; An optical coupler that couples the reflected light at the optical connector junction between the optical connector and the measured optical connector and the reference light, and an adjustment mechanism that adjusts a difference in the propagation optical path length between the reflected light and the reference light; An optical waveform monitor for detecting an interference signal between the reflected light and the reference light combined by the optical coupler is provided.

Another method of measuring the return loss of an optical connector according to the present invention is a method of measuring the return loss at an optical connector connection between a master optical connector and an optical connector to be measured. Is divided into reference light and N measurement lights, and is disposed at a point where the optical path length from the light branching section to each end face is changed by about the coherence length of the light source, and is connected to the optical connector to be measured. The N measurement lights are guided to N master optical connectors, and the reflected light at the N optical connector connection portions and the reference light are coupled with each other, and the propagation optical path length difference between each reflected light and the reference light is calculated. It is characterized by adjusting and causing interference sequentially, and measuring the return loss at each optical connector connection from the intensity of each interference signal.

Further, another optical connector return loss measuring device according to the present invention is a device for measuring a return loss at an optical connector connecting portion between a master optical connector and a measured optical connector, comprising: a light source; An optical splitter connected to the light source and splitting the light emitted from the light source into reference light and N measurement lights; and an optical path connected to the measurement light output side of the optical splitter and extending from the optical splitter to each end face. N master optical connectors arranged at points where the lengths are changed by the coherence distance of the light source and connected to the connector under test, and an optical connector connecting portion between the master optical connector and the optical connector under test. An optical coupler that couples the N reflected lights and the reference light, an adjustment mechanism that adjusts a propagation optical path length difference between the reflected light and the reference light, and each reflected light that is coupled by the optical coupler. An optical waveform monitor that detects an interference signal with the reference light And it said that there were pictures.

[0012]

According to the present invention, the reflected light of the measuring light at the optical connector joint and the reference light are combined by adjusting the difference in the propagation optical path length, and the reflected light at the optical connector joint and the reference light interfere with each other. Since the interference signal power at this time is proportional to the reflected light intensity, the return loss can be measured from the interference signal intensity. In such a case, if there is no reflection point other than the optical connector junction within the coherence distance of the light emitted from the light source, the return loss at the optical connector junction is reduced without being affected by the reflected light at the reflection point. Can be measured. Further, in the present invention, since the coherent detection method in which the reflected light and the reference light interfere with each other, the measurement limit is higher than that of the conventional direct detection method.

Further, when N master optical connectors are arranged, N master optical connectors are arranged at points which are changed by the coherence distance each other, and when the reflected light from each optical connector joint and the reference light are combined, the reference light can be obtained. And the respective reflected lights, the return loss of the N optical connectors to be measured can be separately measured from each interference signal.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.

FIG. 1 shows a first embodiment. In the figure, 1 is a light source, 2 is a 2 × 2 optical fiber coupler, 3 is a master optical connector, 4 is an optical connector to be measured, 5 is an optical waveform monitor, 6
Is a power meter, 7 is a lens, and 8 is a movable mirror. Light source 1
Is connected to the first optical fiber 2A of the optical fiber coupler 2, and the emitted light is split into reference light to the second optical fiber 2B and measurement light to the third optical fiber 2C. Has become. Here, a master optical connector 3 is connected to the third optical fiber 2C, and an optical connector 4 to be measured is joined to the master optical connector 3. On the other hand, a movable mirror 8 movably in the optical axis direction is optically coupled to the end face of the second optical fiber 2B via a lens 7, and the reference light emitted from the end face of the second optical fiber 2B is The second optical fiber 2 is reflected by the movable mirror 8 and again
B is incident from the end face. Then, the reflected reference light and the light reflected at the optical connector junction between the master optical connector 3 and the measured optical connector 4 are coupled by the optical fiber coupler 2 and emitted to the fourth optical fiber 2D. An optical waveform monitor 5 and a power meter 6 are connected to the optical fiber 2D.

In order to measure the return loss at the optical connector junction using the apparatus shown in FIG. 1, the light emitted from the light source 1 is split by the optical fiber coupler 2, and the master optical connector 3 and the optical connector 4 to be measured are separated. The light reflected at the optical connector junction and the reference light reflected by the movable mirror 8 are coupled by the optical fiber coupler 2 and made incident on the optical waveform monitor 5. Then, the light intensity is observed by the optical waveform monitor 5 while moving the movable mirror 8, and the power of the interference signal is measured by the wattmeter 6.

The outputs of the optical waveform monitor 5 and the wattmeter 6 at this time are shown in FIGS. As shown in both figures, the output is maximum at the point where the distance between the optical branch point of the optical fiber coupler 2 and the movable mirror 8 matches the distance from the optical branch point of the optical fiber coupler 2 to the end face of the master optical connector 3. And has a width about the coherent distance L _c of the light source 1. The coherence length _Lc is 1 in a Fabry-Perot laser diode.
cm, and about 0.1 mm for light emitting diodes.

Here, assuming that the electric field amplitude of the reference light is E ₀ , the electric field amplitude of the light incident on the connection between the master optical connector 3 and the measured optical connector 4 is E ₁ , and the reflectance at the connection is R. ,
Field amplitude of the reflected light √R · E _1, and the interference signal intensity I of the output of the waveform monitor 5 in proportion to √R · E ₀ · E _1, the interference signal power P is proportional to RE ₀ ² E ₁ ² And it is proportional to the reflectance R of the joint. Therefore, the maximum value _Pmax of the interference signal is measured, and the signal power _Pmax (10
0%) can be obtained by the following equation (2).

[0019]

(Equation 2)

According to the apparatus shown in FIG. 1, the amount of return loss can be obtained in this manner. However, since the coherent detection is used, even if there is a reflection point other than the optical connector junction, the reflection loss is outside the coherence distance. If you do, you will not be affected.
For example, even if there is a reflection point after the optical connector 4 to be measured, there is no problem as long as it is outside the coherence distance. Absent.

Further, the product of whereas the measurement signal is a direct detection method of the conventional example is proportional to a square of the light source output power measurement signal in coherent detection is the reference optical power E ₀ ² and the reflected light power E ₁ ² That is, it is proportional to the square of the light source output light power. Therefore, for this reason, the present invention can measure the return loss with high measurement sensitivity.

Further, in the coherent detection, the measurement sensitivity can be improved up to the shot noise limit in principle, and the shot noise level Γ _shot (dB) converted into the reflectance is expressed by the following equation (3). In the equation, h is Planck's constant, ν is the optical frequency, B is the band of the receiver, η is the conversion efficiency of the photodetector, and P is the 100% reflected light power.

[0023]

(Equation 3)

Here, ν = 230 THz (wavelength λ = 1.
3 μm), B = 100 Hz, η = 0.75, P = 0.1
When mW, a Γ _shot = 127dB, it can be seen that can measure return loss of about 130 dB.

FIG. 4 shows a second embodiment, and the same members as those in FIG. 1 are denoted by the same reference numerals. As shown in the figure, the present embodiment is different from the diagram in that the second optical fiber 2B of the optical fiber coupler 2 is wound around a cylindrical piezoelectric element (hereinafter referred to as a piezoelectric element) 9 and its end face is opened. 1 has the same configuration.

In this embodiment, the reference light is reflected at the end face of the second optical fiber 2B, and the optical path length of the reference light is controlled by the piezo element 9. That is, the piezoelectric element 9 expands in the radial direction when a voltage is applied, and expands the optical fiber 2B in the longitudinal direction by this expansion to adjust the optical path length.
In this embodiment, the piezo element 9, the diameter of the piezo element 9,
Depending on the number of turns of the optical fiber 2B and the setting of the applied voltage, ΔL =
The optical fiber length can be adjusted to about 0.1 mm, and the refractive index n of the silica-based optical fiber is about 1.5.
An optical path length adjustment of about 1.5 × ΔL is possible. Therefore, a light emitting diode having a coherence distance of 0.1 mm or less is selected as the light source 1, and the second
Up to the end face of the optical fiber 2B and the master optical connector 3
By aligning the optical fiber lengths up to the end face with an accuracy of 0.1 mm or less, the results described with reference to FIGS. 2 and 3 can be obtained as in the first embodiment.

FIG. 5 shows a third embodiment, and the same members as those in FIG. 1 are denoted by the same reference numerals. As shown in the figure, the present embodiment has the same configuration as that of FIG. 1 except that the second optical fiber 2B of the optical fiber coupler 2 is disposed in the temperature controller 10 and its end face is open. I have.

In this embodiment, the reference light is reflected at the end face of the second optical fiber 2B, and the optical path length of the reference light is controlled by the temperature controller 10.
That is, by changing the temperature of the optical fiber 2B by the temperature controller 10, the refractive index thereof is changed to adjust the optical path length.

Temperature dependence of refractive index of quartz optical fiber (1)
/ L) · (dn / dT) is about 10 ⁻⁵ and the coefficient of linear expansion of glass (1 / L) · (dL / dT) is about 10 ⁻⁶ , so that the temperature dependence of the refractive index depends on the optical path length. Almost dominates temperature dependence. Therefore, of the optical fiber 2B, L = 1m
Is changed by ΔT = 10 ° C. to obtain the following equation 4.
The optical path length can be adjusted by about 0.15 mm as shown by, thereby obtaining the results as described in FIGS. 2 and 3 as in the first embodiment.

[0030]

(Equation 4)

FIG. 6 shows a fourth embodiment, and the same members as those in FIGS. 4 and 5 are denoted by the same reference numerals. As shown in the figure, this embodiment is different from the second or third embodiment in that
This is an example for providing a margin for the optical path length adjustment accuracy, and is the same as the second or third embodiment except that the multiple reflection optical thin film 11 having a thickness t is attached to the end face of the optical fiber 2B.
Note that either one of the piezo element 9 and the temperature controller 10 in the drawing is adopted.

In this embodiment, assuming that the reflectance at the joint surface between the thin film 11 and the end face of the optical fiber 2B and the reflectance at the surface where the thin film 11 contacts the air are 50% and 100%, respectively, the reference light is reflected on two surfaces. It is possible to cause multiple reflections and to interfere with points where the optical path lengths differ by 2 nt as shown in FIG.
Therefore, if the thickness t of the thin film 11 is selected to be 2 nt = 0.15 mm so that the reference light exists every 0.15 mm of the optical path length adjustment distance that can be adjusted in the second or third embodiment. The adjustable optical path length can be expanded.
Note that the N-th reference light has a power of (0.5) ^N of the incident light, but originally has a high measurement limit of 130 dB, so that
The measurement result is (0.5) ¹⁰
= 1/1000 = −30 dB, but 100
It is possible to measure dB return loss.

Therefore, in this embodiment, if the optical fiber length from the branch point of the optical fiber coupler 2 to the end face of the master optical connector 3 and the road surface of the optical fiber 2B is adjusted with an accuracy of 1 mm or less, the piezo element 9 or the optical path length adjustment by the temperature controller 10, the reflected light at the end face of the master optical connector 3 can be made to interfere with the reference light that has been multiply reflected within the tenth and the return loss can be measured.

FIG. 8 shows a fifth embodiment, and the same members as those in FIG. 6 are denoted by the same reference numerals. As shown in the figure, the present embodiment is similar to the fourth embodiment in that the second or third
This embodiment is an example for providing a margin for adjusting the optical path length, and is the same as the fourth embodiment except that a part of the third optical fiber 2C is replaced with the birefringent optical fiber 12.

In this embodiment, the birefringent optical fiber 12
Utilizing the fact that the refractive indices are different between the two polarization axes, there is more room for adjustment accuracy of the optical fiber length from the branch point of the optical fiber coupler 2 to the end face of the optical fiber 2B and the end face of the master optical connector 3. .

The birefringence of the birefringent optical fiber 12 is two
It is the refractive index difference of the polarization axis, and B = n₁-N_Two$ 10^-Fourdegree
In a birefringent optical fiber of length L, n₁・ L and n_Two・ L
And there are two optical paths when L = 1 m.
The length difference is n₁・ Ln_TwoL = BL = 100 μm
For example, length L₁= 1m, L_Two= 2m birefringent optical fiber
When the bars 12 are connected in two stages, the combination of the optical path lengths is n_Two
・ L₁+ N_Two・ L_Two, N₁・ L₁+ N_Two・ L_Two= (N_Two
・ L₁+ N_Two・ L_Two) +100 μm, n_Two・ L ₁+ N₁
・ L_Two= (N_Two・ L₁+ N_Two・ L_Two) +200 μm, n
₁・ L₁+ N₁・ L_Two= (N_Two・ L₁+ N_Two・ L_Two) +
Four 100 μm intervals of 300 μm are provided. in this way
With a birefringent optical fiber 12 with a suitably chosen length
Interference can occur at several optical path lengths at intervals. I
Therefore, this allows a margin in the adjustment accuracy of the optical fiber length.
Can be taken.

FIG. 9 shows a sixth embodiment, and the same members as those in FIG. 6 are denoted by the same reference numerals. As shown in the figure, the present embodiment is similar to the fourth embodiment in that the second or third
In this embodiment, the third optical fiber 2C is cut once in the middle and is connected by a V-groove optical fiber connector 13 to allow a margin for adjusting the optical path length. The fourth example is the same as the fourth example except that by adjusting the interval, the margin for adjusting the optical fiber length from the branch point of the optical fiber coupler 2 to the end face of the optical fiber 2B and the end face of the master optical connector 3 is further increased. This is the same as the embodiment.

Assuming that the distance between the optical fiber end faces of the V-groove optical fiber connector 13 is d, the loss of the propagating light is expressed by the following equation (5).

[0039]

(Equation 5)

According to this, even when the length is adjusted to d = 1 mm, the loss is about 6 dB and the round-trip is 12 dB, and it is only necessary to degrade the measurement limit of the return loss by 12 dB. If a refractive index matching agent is applied to the joint, the deterioration can be further suppressed.

As a seventh embodiment, in the second or third embodiment, the optical fiber length adjustment accuracy from the branch point of the optical fiber coupler 2 to the end face of the optical fiber 2B and the end face of the master optical connector 3 Another example for providing a margin will be described.

In this embodiment, a Fabry-Perot laser diode is used as the light source 1 (see FIGS. 4 and 5). The optical spectrum of the Fabry-Perot type laser diode has several longitudinal modes as shown in FIG. 10, and when this is used as the light source 1 and the movable mirror 8 is moved in the configuration shown in FIG. As shown in FIG. 11, the interference signal power is several tens of
Peaks are shown at 0 μm intervals. Therefore, in this embodiment, if the lengths of the optical fibers from the branch point of the optical fiber coupler 2 to the end face of the optical fiber 2B and the end face of the master optical connector 3 are each adjusted with an accuracy of 1 cm, the second or third optical fiber can be adjusted.
There is always one peak in the adjustable range of the optical path length adjusting mechanism (piezo element 9 or temperature controller 10) according to the embodiment, and the return loss can be measured using the peak value.

Although the first to seventh embodiments have been described above, the piezo element 9 and the temperature controller 10 of the second or third embodiment are different from the reference light in that the light reflected by the optical connector junction is propagated. The birefringent optical fiber 11 and the V-groove optical fiber connector 12 of the fourth or fifth embodiment may be provided on the optical fiber 2B side through which the reference light propagates instead of the reflected light. Is also good. In addition,
The seventh embodiment can also be combined with each other. In the above, an example in which the measured optical connector 4 is one is shown.
Next, an example in which N optical connectors under test can be inspected simultaneously will be described.

FIG. 12 shows an eighth embodiment.
The same members as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted. In this embodiment, a 1 × N optical splitter 14 is connected to the third optical fiber 2C of the optical fiber coupler 2 from which the measurement light is emitted, and the measurement light is branched into N light beams. The output optical fiber 15 is connected to the master optical connector 3 to which the measured optical connector 4 is connected.
Here, N pieces of the master optical connector 3, are then measuring from the branch point of the optical fiber coupler 2 by changing the ΔL by optical path length is a coherence length of about L _c of the light source 1. Incidentally, as described above, the coherence length is about 1 cm for a Fabry-Perot laser diode and about 0.1 mm for a light emitting diode.

In order to measure the return loss of the optical connector with the apparatus shown in FIG. 9, the light emitted from the light source 1 is split into the reference light and the measurement light by the optical fiber coupler 2, and the reference light is transmitted from the end face of the optical fiber 2B to the lens 7 The measurement light is reflected by the movable mirror 8 through the optical path, and is divided into N by the 1 × N optical splitter 14 so as to be incident on the joint portion between the N master optical connectors 3 and the measured optical connectors 4. Thus, assuming that the refractive index is n, the reflected light from the N optical connector junctions goes back through the 1 × N optical splitter 14 with a delay of 2nΔL in the propagation optical path length and is coupled with the reference light by the optical fiber coupler 2. Is done. When the propagation optical path length of the reference light is changed by the movable mirror 8, the reference light sequentially interferes with the reflected light having the same optical path length from the optical branching portion of the optical fiber coupler 2, and the subsequent stage of the optical waveform monitor 5. The output of the wattmeter 6 provided in FIG.

Here, the electric field amplitude of the reference light is E₀, Nth
Light incident on the connection between the master optical connector and the measured optical connector
Field amplitude of E_N, The reflectance of the connection portion is R_NThen, anti
The electric field amplitude of the emitted light is √R_N・ E_NAnd the waveform monitor
Interference signal strength I_N√R_N・ E ₀・ E_NIs proportional to
Signal power P is R_NE₀ ^TwoE_N ^Two And the reflectance R of the joint is proportional to _N
Is proportional to Therefore, the maximum value P of each interference signal_NmaxTo
When measured, each master optical connector 3 has a 100% reflectance.
Signal power P_Nmax(100%) return loss
Γ_N(DB) is obtained by the following equation (6).

[0047]

(Equation 6)

In coherent detection, as described above, 13
The return loss of about 0 dB can be measured. However, in the measurement of N optical connectors, the reflected light is reciprocated and the power is N1 / ^2.
To decline. However, for example, the signal when N = 128 is (1/128 ² ) = 6 × 10 ^{−5 as} compared with the signal when N = 1.
= −42 dB, and a return loss measurement of about 90 dB is still possible, far exceeding the conventional measurement limit of 60 dB. Note that the second to seventh embodiments described in the present embodiment are described above.
It is needless to say that if the embodiment is applied, it is possible to provide a margin for the adjustment accuracy of the optical fiber length.

[0049]

As described above, the light emitted from the light source is split into the measuring light and the reference light, the measuring light is sent to the master optical connector, and the reflected light at the optical connector junction and the reference light are combined. If there is no reflection point other than the end face of the optical connector to be measured within the coherent distance of the light emitted from the light source, the difference in the propagation optical path length between the reflected light of the end face of the optical connector to be measured and the reference light can be obtained. By adjusting, only the reflected light from the end face of the optical connector under test can interfere with the reference light, and the interference signal power is proportional to the reflected light intensity. It can be measured at a high measurement limit without suffering. Further, the measuring light is further branched into N light beams, and the branched light beams are sent to a master optical connector arranged at a point where the coherent distance of the light source is changed by a coherent distance. In this case, the reference light and the N reflected lights are sequentially caused to interfere with each other by one time adjustment of the propagation optical path length difference, and the return loss of the N optical connectors to be measured is separately measured from the interference signal. This makes it possible to measure the return loss of a large number of optical connectors without processing the end face of the non-measurement connector and performing a single measurement operation.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is an explanatory diagram illustrating an example of an output of an optical waveform monitor.

FIG. 3 is an explanatory diagram illustrating an example of an output of a wattmeter.

FIG. 4 is a configuration diagram showing a second embodiment.

FIG. 5 is a configuration diagram showing a third embodiment.

FIG. 6 is a configuration diagram showing a fourth embodiment.

FIG. 7 is an explanatory diagram showing the operation of the fourth embodiment.

FIG. 8 is a configuration diagram showing a fifth embodiment.

FIG. 9 is a configuration diagram showing a sixth embodiment.

FIG. 10 is a diagram showing an optical spectrum of a Fabry-Perot laser diode.

FIG. 11 is an explanatory diagram showing interference signal power according to a seventh embodiment.

FIG. 12 is a configuration diagram showing an eighth embodiment.

FIG. 13 is an explanatory diagram showing interference signal power according to the eighth embodiment.

FIG. 14 is a configuration diagram showing a conventional technique.

[Explanation of symbols]

 Reference Signs List 1 light source 2 optical fiber coupler 2A to 2D optical fiber 3 master optical connector 4 optical connector to be measured 5 optical waveform monitor 6 wattmeter 7 lens 8 movable mirror 9 cylindrical piezoelectric electrostrictive element 10 temperature controller 11 optical thin film for multiple reflection

Claims (2)

(57) [Claims] A light source connected to the light source and emitting light emitted from the light source;
Optical splitter that splits into measurement light and reference light, and measurement of the splitter
Connected to the light emitting side and connected to the optical connector to be measured
Master optical connector and master optical connector
The reflected light at the optical connector connection to the optical connector and the reference light
Coupler that couples light and an adjusting device that adjusts the difference in the propagation optical path length
Interference between the reflected light and the reference light combined by the optical coupler
Connector return attenuation equipped with a photodetector for detecting a signal
In a mass measuring apparatus, the light source has a Fabry-Perot type laser having a plurality of longitudinal modes.
Optical connector reflection characterized by laser diode
Attenuation measurement device. 2. An optical connector return loss measuring apparatus according to claim 1,
In the constant device, adjusting mechanism for adjusting the propagation optical path length difference of the optical fiber Shin
Optical connector return loss measuring device characterized by shrinking
Place.