JPH10239556A - Optical module measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an efficient optical module measuring device capable of conducting the pre-processing work in a short time and excellent in accuracy and reproducibility. SOLUTION: The end faces of input fibers 11 of an optical module 1 are aligned and held by a jig 51 at prescribed intervals, and the end faces of output fibers 12 are aligned and held by a jig 52 at prescribed intervals. The end section of a light projecting fiber 22 is held on a jogging base 41 via a jig 53. A slit 32 and a light detector 31 are mounted on a jogging base 42. A control device 7 is provided. The control device 7 receives the detection signal 81 from the light detector 31, sends control signals 82, 83 to the jogging bases 41, 42 respectively so that the output light power from the optical module 1 becomes the maximum, and makes alignment between the light projecting fiber 22 and input fibers 11 and alignment between the light detector 31 and output fibers 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module used for optical communication, and more particularly to a measuring apparatus for an optical module having multiple input / output fibers.

[0002]

2. Description of the Related Art In order to improve the function and economy of optical communication services, optical modules used have been integrated, compounded and multi-ported, and have a plurality of input / output fibers. At the same time, there is a demand for highly accurate and economical measurement of optical module characteristics. Conventionally, the following three methods have been mainly used for measuring the characteristics (insertion loss, polarization dependent loss (PDL), return loss) of an optical module. A method of connecting a connector to each end face of the input (or output) fiber of the optical module and the projecting (or receiving) fiber of the measuring instrument (connector connection method). A method in which the input (or output) fiber of the optical module and the light emitting (or light receiving) fiber of the measuring instrument are end-face-connected by a microcapillary or V-groove (simple connection method). A method of fusing the input (or output) fiber of the optical module with the light emitting (or receiving) fiber of the measuring instrument (fusion splicing method).

[0003] Among them, an optical module measuring apparatus using the fusion splicing method with the highest accuracy, particularly a loss measuring apparatus and a measuring procedure will be described with reference to FIGS. 3 (a) and 3 (b). FIG.
(A) is a measurement system when the optical module is inserted. In this measuring device, the input fiber 11 of the optical module 1 is connected to the fusion section 9.
1 is fused to the light projecting fiber 22 and the output fiber 12
Is fusion-spliced to the light receiving fiber 34 at the fusion splicing portion 92. The output light of the light source 21 is transmitted through the optical switch 23 to the light emitting fiber 2.
Lead to 2. The optical switch 23 selects a port to be measured. One of the output lights received by the light receiving fiber 34 is selected by the optical switch 33 and detected by the photodetector 31. In general, the light projecting system 2 includes optical devices such as an optical switch, a wave plate, a polarizer, an optical coupler, and a splitter, and a device such as a return loss measuring device and a polarization rotation module, in addition to the light source 21 in accordance with a measurement item. It consists of. The optical module measuring device shown in FIG. 3A measures a loss between all input / output ports of an optical star coupler module having M inputs and N outputs (M ≧ 2, N ≧ 2).

FIG. 3B shows a measurement system at the time of reference measurement. Each combination of the light projecting fiber 22 and the light receiving fiber 34 is fused, and based on the data obtained from this measurement system, the output light power of the light source 21 and the optical switches 23 and 3
Correct the loss at 3. When the loss of a 32 × 32 optical star coupler module is measured and eight fusion splices can be performed at a time, it is necessary to insert the optical module into the measuring device eight times and to perform the reference measurement at least eight times. It is necessary to fuse several times.

[0005]

However, such conventional measurement of the characteristics of an optical module has the following problems. When the connector connection method is used, it takes time and effort to attach a connector to the optical module, which is not economical. Also, since automation of connector connection is not easy,
The characteristic measurement of the optical module having the multi-core input / output fiber cannot be performed efficiently. Furthermore, the connector connection usually has an average connection loss of about 0.3 dB, and the loss varies by about 0.2 dB depending on the combination of the connectors to be connected. Therefore, the accuracy and reproducibility of the measurement result are insufficient. In the case of using the simple connection method, it does not take much time to attach a connector, but there is a connection loss and a variation similar to those of the connector. When the fusion splicing method is used, a considerable amount of labor and time are required for fusion. In particular, in the case of an optical module having multiple input / output fibers, fusion must be performed a number of times for insertion of the optical module and reference measurement, which is not efficient. Further, the connection loss is usually as good as 0.1 dB or less, but sometimes an excessive loss may occur due to poor fusion, and it cannot be confirmed and corrected.

That is, in the conventional method, in order to inspect and measure the characteristics of the optical module, a pre-processing operation requiring a long time, such as connector attachment and fusion, is required.
It was not efficient and had difficulty in accuracy and reproducibility.

The present invention has been made in order to solve such a problem, and it is an object of the present invention to perform a pre-processing operation in a short time, and to provide an efficient, high-precision, and excellent reproducibility. An optical module measuring device is provided.

[0008]

In order to achieve the above object, a first invention (an invention according to claim 1) is a first invention for holding an aligned end face of an input fiber of an optical module at a predetermined interval. A first jig and a second jig for holding the aligned end faces of the output fibers of the optical module at predetermined intervals;
A light source, one light emitting fiber for guiding the optical power from the light source to the input fiber by end face coupling, a slit for selectively passing outgoing light from one of the output fibers, and passing through this slit A light detector for detecting the output light from the output fiber, and aligning the light emitting fiber and the input fiber and aligning the light detector and the output fiber so that the power of the output light is maximized. Means. According to the present invention, the power of the output light from the output fiber passing through the slit is maximized,
Alignment of the light projecting fiber with the input fiber of the optical module held by the first jig and alignment of the photodetector with the output fiber held by the second jig are performed. According to a second invention (an invention according to claim 2), in the first invention, a light receiving fiber for guiding the light emitted from the output fiber of the optical module to the photodetector is used instead of the slit.
According to the present invention, the centering of the light projecting fiber and the input fiber of the optical module held by the first jig is performed so that the power of the light emitted from the output fiber guided using the light receiving fiber is maximized. The alignment between the photodetector and the output fiber held by the second jig is performed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. [Embodiment 1] FIGS. 1A and 1B show an optical module measuring apparatus (M input (M ≧ 2), N output (N ≧
2) shows a measuring system when the optical module is inserted and a measuring system when the reference is measured in the optical star coupler insertion loss measuring device 2).

As shown in FIG. 1A, the input fiber 11 of the optical module 1 is held by a jig 51 at predetermined intervals with its end faces aligned, and the output fiber 12 is aligned with its end faces at predetermined intervals. The jigs 52 are held at predetermined intervals. The light projecting system 2 includes a light source 21, and guides output light from the light source 21 to the input fiber 11 through the light projecting fiber 22. The end of the light projecting fiber 22 is held on the fine moving table 41 via a jig 53. By moving the fine movement table 41, the end face of the light projecting fiber 22 is made to face one fiber end face of the input fiber 11. In order to reduce reflection and loss at the connection portion, the gap between both end surfaces is set to 10 μm or less, and the refractive index matching material 6 is formed.
Fill with. The slit 32 and the photodetector 31 are mounted on a fine movement table 42 and move together. Outgoing light from the output fiber 12 is selectively passed through one fiber through the slit 32 and guided to the photodetector 31.

Reference numeral 7 denotes a control device which takes in a detection signal 81 from the detector 31 and applies control signals 82 and 83 to fine adjustment tables 41 and 42 respectively so that the output light power from the optical module 1 becomes maximum. The transmission and alignment of the light projecting fiber 22 and the input fiber 11 and the alignment of the photodetector 31 and the output fiber 12 are performed.

The light source 21 is a 1.3 μm semiconductor laser (L
This is an LD light source that incorporates D) and 1.55 μm LD and can select either wavelength. The slit 32 selectively allows only one out of the light emitted from the plurality of output fibers 12 to pass. If the slit width is too narrow, light emitted from the output fiber 12 may be blocked.
Since the alignment accuracy of (2) also becomes severe, it is better that the slit width is wide as long as stray light from other output fibers or the like does not enter.
Therefore, the slit width was set to about 125 μm, which is about the outer diameter of the fiber.

The fine moving table 41 is a normal moving stage that can finely move with a resolution of 0.1 μm in two axes parallel to the end face of the fiber (vertical direction on the paper, front and back on the paper). The connection loss is 0.
Since the fiber position shift amount of 1 dB is about 0.7 μm, a resolution of 0.1 μm is sufficient. With this resolution, the connection loss can be secured to 0.05 dB or less.

The fine moving table 42 is an ordinary moving stage which can be finely moved in the axial direction (vertical direction on the paper) where the end faces of the output fibers 12 are aligned. The optical power from the output fiber 12 is emitted into the air, and the light
Since detection is performed at 1, the resolution of the fine moving table 42 is determined by the width of the slit 32. As described above, since this slit width is about 125 μm, which is about the outer diameter of the fiber, 10 μm
Even if the slit position is shifted by about m, the power of all the emitted light can be detected.

Here, the light receiving diameter of the photodetector 31 needs to be sufficiently larger than the spread of the emitted light in order to reliably receive all of the emitted light from the output fiber 12. At this time, since the light emitted from the output fiber 12 needs to pass through the slit 32 as well,
Of the output fiber 12 from the end face of the
Can be determined in consideration of the distance from the end surface to the light receiving surface. In this embodiment, a light receiving diameter of 2 mm is used in consideration of these parameters and their setting errors.

The jigs 51 and 52 are formed with V grooves in parallel with the fiber outer diameter of 250 μm, which is twice the fiber outer diameter, which is the fiber spacing of a normal multi-core fiber ribbon. The input and output fibers 11, 12 which have been roughly aligned and cut in a lump beforehand are placed in the V-grooves of the jigs 51, 52, and the end faces of the input and output fibers 11, 12 are aligned and held by lightly pressing from above. Since the alignment accuracy of the output fiber 12 may be about 10 μm, the accuracy of the V groove of the jig 52 may be about the same.
On the other hand, in the connection of the end face of the input fiber 11, the connection loss is 0.1.
dB or less is required.
Since the fine movement table 41 of m is controlled and aligned, the accuracy of the V-groove of the jig 51 may be about 2 μm. Machining accuracy of about 2 μm can be easily achieved with ordinary numerically controlled machine tools.

The measurement procedure will be described below. First, FIG.
As shown in (a), the input fiber 1 of the optical module 1
1 is held by a jig 51 at predetermined intervals with its end faces aligned, and held by a jig 52 at predetermined intervals with the end faces of the output fibers 12 of the optical module 1 aligned. Then, for each of the M input fibers 11, the light projecting fiber 2
2 and further, for each of the N light receiving fibers 32, the photodetector 31 is aligned, 1.3 μm light is selected and the light output P ₃ is measured, and 1.55 μm light is selected and the light output P is selected. Measure ₅ . Therefore, the input / output fiber M
The measurement for two wavelengths is performed for all of the × N sets.
All this can be done automatically.

Next, reference measurement is performed as shown in FIG. The optical module 1 is removed, and the light projecting fiber 22 is placed on the jig 52 and held. The photodetector 31 is aligned, 1.3 μm light is selected, and the light output P _R3 is measured.
1.55 μm light is selected and the light output P _R5 is measured. This reference measurement may be performed prior to the module measurement.

When each optical output is measured in dBm and the loss is given in dB, the loss L in the 1.3 μm LD light source
_3, and, loss L ₅ in 1.55μmLD light source, _{respectively, L 3 (dB) = P} R3 (dBm) -P 3 (dBm) L 5 (dB) = P R5 (dBm) -P 5 (dBm ).

When this measuring apparatus is used, the input / output fibers 11 and 12 are used for inspecting and measuring the characteristics of the optical module 1.
Since there is no need for pre-processing such as connector attachment or fusion bonding, it is efficient and requires no labor or time. Further, since the light projecting fiber 22 and the input fiber 11 are aligned by end face coupling so that the output light power from the optical module 1 is maximized, the connection loss on the input fiber side is excellent in reproducibility and 0.1%.
dB or less. At the same time, only one of the output lights of the plurality of output fibers 12 is selectively passed through, detected by the photodetector 31 having a relatively large light receiving area, and the alignment and measurement are performed so that the detected light amount becomes maximum. Therefore, there is no connection loss on the output fiber side in principle, and highly accurate measurement is possible.

Further, since the input / output fibers 11 and 12 of the optical module 1 are held at predetermined intervals with their end faces aligned, the input / output fibers to be easily measured by moving the fine movement tables 41 and 42 Can be selected and aligned. In addition, since the number of the light projecting fibers 22 is one, and the optical power is detected through one slit 32, the reference measurement only needs to be performed once, which is efficient.

In this embodiment, an example has been described in which the light projecting fiber 22 and the photodetector 31 are mounted on the fine moving tables 41 and 42, respectively. Combinations are not limited to this,
A combination of the light projecting fiber 22 and the output fiber 12, a combination of the input fiber 11 and the photodetector 31, and a combination of the input fiber 11 and the output fiber 12 are also possible. It is possible to configure a loss measuring device having the same function as the above.

Further, the number of fine movement tables used for the movement alignment is not limited to one.
Table, light projecting fiber 22 and input fiber 1
The present invention also includes a case where the fine movement table that aligns with 1 is separated and differentiated.

Further, the present invention is not limited to the M × N star coupler module, but can be applied to loss measurement of other optical modules such as an optical splitter, a wavelength multiplexer / demultiplexer, and a wavelength-independent coupler. Further, the light source has a wavelength of 1.
The light source is not limited to the LDs of 3 μm and 1.55 μm, and a light source of any wavelength to be measured may be used. In addition, by incorporating a polarization rotation module into the light projecting system, it functions as a polarization dependent loss measuring device, and by incorporating a return loss measuring device, it can function as a return loss measuring device for multi-core ports. it can.

[Second Embodiment] In the second embodiment, instead of the slit 32 in the first embodiment, a light receiving fiber 34 (FIG. 2) for guiding the light emitted from the output fiber 12 of the optical module 1 to the photodetector 31 is used. (See (a) and (b)).

In FIG. 2A, a light receiving fiber 34 is held via a jig 54 on a fine moving table 42 located at a position facing the output fiber 12 of the optical module 1. The gap between the end faces of the output fiber 12 and the light receiving fiber 34 is filled with the refractive index matching agent 6. The control device 7 takes in the detection signal 81 and sends out control signals 82 and 83 to the fine moving tables 41 and 42, respectively, so that the output power from the optical module 1 is maximized, and sends the light projecting fiber 22 and the input fiber 11 And the light receiving fiber 31 and the output fiber 12 are aligned.

The light receiving fiber 34 is the same single mode fiber as the output fiber 12 of the optical module 1,
Alternatively, a fiber having a core diameter larger than the core diameter of the output fiber 12 of the optical module 1, for example, a GI multimode fiber having a core diameter of 50 μm can be used. When the former single mode fiber is used, a fine moving table 42 having a feed accuracy equivalent to that of the fine moving table 41 for the light emitting fiber is required. However, when the latter multimode fiber is used, a finer moving table 42 is required. A low feed rate, for example, about 1 μm, is sufficient.

[0028]

As is apparent from the above description, according to the present invention, in the first invention, the light output from the output fiber passing through the slit is maximized, and in the second invention, the light receiving The alignment between the light projecting fiber and the input fiber of the optical module held by the first jig, the light detector and the second detector, so that the power of the output light from the output fiber guided using the fiber is maximized. Since the alignment with the output fiber held by the jig is performed, the pre-processing work can be performed in a short time, and an optical module measuring device that is efficient and has excellent accuracy and reproducibility can be realized. become able to.

[Brief description of the drawings]

FIG. 1 is a diagram showing a measurement system and a reference measurement system when an optical module is inserted in an optical module measurement device (first embodiment) according to the present invention.

FIG. 2 is a diagram showing a measurement system and a reference measurement system when an optical module is inserted in an optical module measurement device (Embodiment 2) according to the present invention.

FIG. 3 is a diagram showing a measurement system and a reference measurement system when an optical module is inserted in an optical module measurement device using a conventional fusion splicing method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical module, 11 ... Input fiber, 12 ... Output fiber, 2 ... Projection system, 21 ... Light source, 22 ... Projection fiber, 31 ... Photodetector, 32 ... Slit, 34 ... Receiving fiber, 41, 42 ... Fine table, 51, 52, 53, 54 ...
Jig, 6: refractive index matching material, 7: control device, 81: detection signal, 82, 83: control signal.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Sumita 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Co., Ltd. No. Japan Telegraph and Telephone Corporation

Claims (2)

[Claims] 1. An optical module measuring device having multi-core input / output fibers, comprising: a first jig for holding aligned end faces of input fibers of the optical module at predetermined intervals; and the optical module. A second jig for holding the aligned end faces of the output fibers at predetermined intervals, a light source, one light emitting fiber for guiding the optical power from the light source to the input fiber by end face coupling, and A slit for selectively passing outgoing light from one of the fibers, a photodetector for detecting the outgoing light from the output fiber passing through the slit, and a power of the outgoing light being maximized. Means for aligning the light projecting fiber with the input fiber and aligning the photodetector with the output fiber. 2. The optical module measuring device according to claim 1, wherein a light receiving fiber for guiding light emitted from an output fiber of the optical module to the photodetector is used instead of the slit.