JPH04194807A - Array type optical multiplexer/demultiplexer - Google Patents

Abstract

PURPOSE:To facilitate connection of a tape fiber by disposing a light signal emitting part so that a demultiplexed light signal is emitted from the end surface of a cladding layer different at every wave length. CONSTITUTION:A photo signal is inputted to respective optical multiplexing/ demultiplexing waveguides 3a - 3d, where the light signal is branched into a light signal of wavelength lambda1 is propagated through linear waveguides 6a - 6d and emitted from light signal emitting parts 9a - 9d on the end surface R side. The light signal lambda2 is reflected by end surfaces 12a - 12d of bent parts 11a - 11d and propagated through waveguides 7a - 7d and emitted from light signal emitting parts 10a - 10d on the end surface D side, As noted above, since the light signal of the wavelengths lambda1 is completely separated away from the light signal of the wavelength lambda2, a four-fiber tape is collectively connected classified by an emission wavelength to the end surfaces R and D. Namely, the tape fibers for signal transmission and for trouble diagnosis can be arranged in a completely separated state. Further, the tips of the bent parts 11a - 11d are cut at an angle of 45 deg. and propagation light is wholly reflected by the end surfaces thereof, whereby a propagation loss owing to bending of a propagation route is prevented from incurring.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an array-type optical multiplexer/demultiplexer for diagnosing failures in optical fiber transmission lines for information transmission. The present invention relates to an array type optical multiplexer/demultiplexer in which tape fibers can be easily connected by arranging optical signal emitting portions so that the optical signals are emitted from end faces of different cladding layers.

“Conventional technique #I” Optical multiplexer/demultiplexer, which has the function of multiplexing and demultiplexing optical signals of different wavelengths, is used not only for wavelength division multiplexing transmission systems but also for failure diagnosis systems for optical fiber transmission lines and It is also being applied to failure monitoring systems, etc.For example, when monitoring and controlling multiple optical fiber transmission lines by installing individual optical multiplexers/demultiplexers on multiple optical fiber transmission lines, array-type optical multiplexers/demultiplexers are used. An array type optical multiplexer/demultiplexer is a directional coupler formed by covering a core waveguide on a substrate 1 with a cladding layer 2, as shown in FIGS. 5(a) and 5(b). By configuring a so-called waveguide structure in which a plurality of type optical multiplexers/demultiplexers 3a to 3d are formed in parallel, it is possible to mass-produce it and achieve it at a very low cost. The demultiplexer inputs a combined optical signal of two wavelengths λ1 and λ2 into the optical signal input sections 8a to 8d, and demultiplexes the light into single components of wavelengths λ1 and λ2 and outputs the light. It is configured like this.

[Problem B to be Solved by the Invention] However, when attempting to connect an optical fiber transmission line to the array type optical multiplexer/demultiplexer shown in FIG. 5, it has been found that the following problems occur. That is, while an optical fiber transmission line is usually composed of four-core tape fibers, the array type optical multiplexer/demultiplexer shown in FIG.
It has a structure in which optical signal emitting sections 4 of , and optical signal emitting sections 5 of wavelength λ2 are arranged alternately. In the sub-), only the optical signal output part 4 of one wavelength λ1 is connected with the first tape fiber of 4 fibers, and the optical signal output part 5 of the remaining wavelength λ is connected with the second tape fiber of 4 fibers. 7':4 The problem is that it is only possible to apply a 4-core tape fiber to the J- array type optical multiplexer/demultiplexer, but it is only possible to connect single-core optical fiber transmission lines individually. However, it was later necessary to separate and rearrange the optical fiber transmission lines for wavelength λ1 and wavelength λ2. As a result, the cost increases and the advantages of configuring the optical multiplexer/demultiplexer in an array are lost.

An object of the present invention is to solve the above-mentioned problems and to bundle tape fibers for each output wavelength into an optical signal output section for outputting optical signals demultiplexed by respective optical multiplexers and demultiplexers arranged in an array. The object of the present invention is to provide an array-type optical multiplexer/demultiplexer that can be connected.

[Means for solving the problem] In order to achieve the above object, the array type optical multiplexer/demultiplexer of the present invention multiplexes optical signals of a plurality of different wavelengths.

A plurality of optical multiplexing/demultiplexing waveguides for demultiplexing or multiplexing/demultiplexing are formed in parallel on the same substrate, and an optical signal output part is provided to extract the optical signal after demultiplexing from each optical multiplexing/demultiplexing waveguide. They are guided to different end faces of the substrate for each wavelength, and arranged in parallel for each wavelength.

At least one optical signal output portion of the optical multiplexing/demultiplexing waveguide is an abbreviated curved waveguide.

Further, a reflective end face having an angle of approximately 45 degrees with respect to the waveguide direction may be formed at the tip of the bent portion of the curved waveguide, and the reflective end face may be exposed so as to come into contact with air.

A fiber connector for tape fiber connection may be connected to the end face of the cladding layer where the optical signal output section is provided.

U effect j Optical signals of a plurality of different wavelengths incident on the array type optical multiplexer/demultiplexer enter the optical multiplexer/demultiplexer waveguide formed in an array,
After being demultiplexed here, it propagates to the optical signal output side. Since the optical signal output section is disposed on a different cladding layer end face (i.e., on a substrate @ surface) for each output wavelength, the demultiplexed optical signal is emitted from a different cladding layer end face for each output wavelength. This makes it possible to connect the tape fibers to the optical signal output section at once for each output wavelength.

By making at least one optical signal output part of the optical multiplexing/demultiplexing waveguides h7' and -h provided in an array into an approximately J-shaped/'') curved waveguide, the optical signals after demultiplexing have the same wavelength. The optical signal is emitted in a direction approximately 90 degrees away from other optical signals having different angles.

By forming the reflective end face at the tip of the bent part, the split light can be totally reflected at the reflective end face and its propagation direction can be changed by approximately 90 degrees, so the propagation loss due to the provision of the bent part can be reduced. It can be kept to a very low level.

By connecting a fiber connector for connecting the tape fiber to the end face of the optical signal outputting section, the tape fiber can be easily connected to the array type optical multiplexer/demultiplexer. ``Example'' Next, an example of the present invention will be described with reference to FIGS. 1 to 4.

The array type optical multiplexer/demultiplexer shown in Fig. 1(a>,(b)) has two
Four directional coupling type optical multiplexing/demultiplexing waveguides 3a to 3d are arranged in an array to separate optical signals of two different wavelengths λ1 and λ2. The waveguide is constructed as an embedded type. That is, within the cladding layer 2 with a low refractive index nc formed on the substrate 1, an optical refractive index n w (> n c )
It is mainly composed of embedded core waveguides #I6a to 6d and 7a to 7d. The linear core waveguides 6a to 6d, which are provided in parallel to each other so as to penetrate between the opposing end faces R of the cladding layer 2, have the above-mentioned wavelengths λ1 and λ.
Optical signal input parts 8a to 8d for inputting the optical signals of No. 2
are arranged near the end face, and optical signal output sections 9a to 9d for outputting the demultiplexed optical signal of one wavelength λ1 are arranged on the end face R. The core waveguides 24a to 24d, which form pairs with these linear core waveguides 6a to 6d to constitute the four optical multiplexing/demultiplexing waveguides 3a to 3d, are bent at approximately 90 degrees toward the respective demultiplexed light output sides. Curved waveguide 7 having portions 11a to lid
A to 7d are connected to form an abbreviated shape.

As a result, an optical signal output section for outputting the optical signal of the other wavelength λ2 is provided on the end surface where the optical signal input sections 8a to 8d and the optical signal output sections 9a to 9d are formed, and on an end surface different from R. 10a to 10d are formed. The bent ends of the bent portions 11a to 11d of the curved waveguides 7a to 7d are cut at an angle of approximately 45 degrees with respect to the waveguide direction, as shown in FIG. 1(b). The cladding layer 2 has cut end faces 12a to 12a of these bent portions 11a to lid.
Clean 1 in a rectangular shape to expose 12d and bring it into contact with air.
3a to 13d are formed.

Note that a metal film may be deposited on the end surfaces 12a to 12d.

Further, a four-core tape fiber connector (not shown) is attached to the end face R of the cladding layer 2 where the optical signal output parts 9a to 9d are formed and the end face where the optical signal output parts 10a to 10d are formed. .

Next, the operating principle of this array type optical multiplexer/demultiplexer will be explained.

The linear core waveguides 6a to 6d have two different wavelengths λ1. An optical signal of λ2 is input. The optical signal enters each of the optical multiplexing/demultiplexing waveguides 3a to 3d, where it is demultiplexed into an optical signal with a wavelength λ1 and an optical signal with a wavelength λ2. One optical signal of wavelength λ1 is guided by a linear wave F! The light propagates through @6a to 6d and is emitted from the optical signal output portions 9a to 9d of the end surface R111. The other optical signal with wavelength λ2 is transmitted through curved waveguides 7a to 7d.
propagate within. During propagation within the waveguides 78 to 7d, the optical signal is transmitted to the end faces 12a to 12d of the bent portions 11a to lid.
, and the traveling direction is changed to a direction substantially perpendicular to the traveling direction of the optical signal propagating in the linear waveguides 6a to 6d. The optical signal of wavelength λ2 is transmitted to the optical signal input section 8
a to 8d and the end face where the optical signal emitting parts 9a to 9d are formed, and the optical signal emitting parts 10a to 10d on the end face side different from R.
More radiation is emitted.

In this way, the side from which the optical signal of wavelength λ1 is emitted is completely separated from the side from which the optical signal of wavelength λ2 is emitted from the other side, so the 4-core tape fiber is emitted from the end face R and around the end face. Each wavelength can be connected all at once. In other words, since the tape fiber for signal transmission and the tape fiber for fault diagnosis (or monitoring) can be placed completely separate, handling becomes easier and the cost of the fault diagnosis (or monitoring) system can be reduced. can.

Further, the tips of the bent portions 11a to lid bent at a substantially right angle are cut off at an angle of about 45 degrees, and the end surfaces 12a to 12
By exposing d, the propagating light is transmitted to the end surfaces 12a to 1.
Total reflection occurs at 2d. As a result, propagation loss caused by bending the optical signal propagation path at a substantially right angle can be completely prevented.

FIG. 2 shows how to reduce the amount of leakage of the optical signal of wavelength λ2 into the optical signal of wavelength λ1 emitted from the optical signal output parts 9a to 9d on the end surface R side. Waveguide F! @ Directional couplers 17a to 1 separately for 6a to 6d
7d. Directional couplers 17a-17
d has the same characteristics as the optical multiplexing/demultiplexing groove waveguides 3a to 3d, and is configured to distribute the optical signal of wavelength λ2 and pass the optical signal of wavelength λ1 as is.

- As an example, in the array type optical multiplexer/demultiplexer shown in FIG. 2, the calculation results of the demultiplexing characteristics when optical signals with wavelengths λ: and λ2 are input to the optical signal input terminal 8a are shown in FIG. 3 (a> , (b
). FIG. 3(a) shows the optical signal output section 9a on the end surface R side.
Demultiplexing characteristics to ~9d.

FIG. 3(b) shows the optical signal output portion 10a of the end face D11]1.
It shows the demultiplexing characteristics to 10d. From this result, it can be seen that the leakage of the optical signal with the wavelength λ2 into the optical signal output parts 9a to 9d with the wavelength λ1 is extremely small, and high isolation characteristics are obtained. Therefore, the curved waveguides 7a to 7
Even higher isolation characteristics can be expected by providing the blFI with a directional coupler, filter, ring resonator, etc. for preventing leakage of optical signals with wavelengths λ.

Figure 4 shows three different wavelengths λ1. This figure shows an example in which the incident optical signals of λ2 and λ are divided into optical signals of individual wavelengths and outputted. In this case, the directional coupling type optical joint venture/I! Waveguide 14a.

14b is the wavelength λ1. of the incident optical signal. The optical signal of wavelength λ2 is passed through, and the optical signal of wavelength λ2 is transmitted to the optical signal output section 18 on the end face.
The optical multiplexing/demultiplexing waveguides 15a and 1b pass the optical signal with the wavelength λ to the optical signal output portions 20a and 2Ob of the end surface R, and transmit the optical signal with the wavelength λ3 to the end surface U. It is configured to separate the optical signal into the optical signal output sections 19a and 19blJ11. Incidentally, as in the above embodiment, the tips of the bent portions 21a to 21d of the waveguide are cut off at an angle of 45 degrees, and the cladding layer 2 is cut to expose the end surfaces 22a to 22d of the bent portions 2] and a to 21d. Sections 16a to 16d are formed.

The present invention is not limited to the configuration shown in the above embodiments, and the number of optical multiplexing/demultiplexing waveguides formed in an array may be several hundreds as long as it is two or more. For example, even if the optical signals to be input to the optical signal input section have four or more different wavelengths, the number of optical multiplexing/demultiplexing waveguides that can divide the signals into individual wavelengths can be set up in an array, and the optical signals can be emitted. By forming a section at the end face position of the cladding layer for each wavelength, the tape fibers can be collectively connected to the optical signal input terminal of each wavelength.

[Effects of the Invention] In summary, according to the present invention, tape fibers can be connected to an array type optical multiplexer/demultiplexer at once for each output wavelength, which facilitates handling and facilitates failure diagnosis of optical fiber transmission lines. (or monitoring) system costs can be reduced.

[Brief explanation of the drawing]

FIG. 1(a) is a side view showing an actual example of the present invention, FIG. 1(b) is a sectional view taken along line I-I of FIG. 1(a), and FIGS. 2 and 4 are views of the present invention. A sectional view showing another embodiment, FIG. 3(a)
, (b) is a graph showing the calculation results of the demultiplexing characteristics in the array type optical multiplexer/demultiplexer shown in Fig. 2, Fig. 5 (a> is a side view showing the conventional example, and Fig. 5 (b) is the 5(a). In the figure, 2 is a cladding layer, 3a to 3d, 4a. 4b, 5a, 5b are optical multiplexing/demultiplexing waveguides.
are curved waveguides, 9a to 9d, 10a to 1. Od. 18a, 18b, 19a, 19b, 20a. 20b is an optical signal output section, lla to lld, 21a to 2
1d is a bent portion, 12a to 12d, 22a to 22d are reflective end faces, L, R, D are substrate end faces. Patent applicant: Hitachi Cable Co., Ltd. Representative Patent Attorney Nobuo Kinutani Wataru Fukazawa 1, Indication of the case Patent Application No. 2-156718 2, Name of the invention Array type optical multiplexer/demultiplexer 3, Person making the amendment Relationship to the case Patent applicant (512 + Hitachi Cable Co., Ltd. 4, Agent) Postal code: 105 Atagoyama Lawyer Building, 1-6-7 Atago, Minato-ku, Tokyo Telephone: (03) 3436-3744 (Main) [6802]
Patent Attorney Itome Tani F. 5. Date of amendment order: January 28, 1992 (shipping mill) 6. Specification subject to amendment (column for brief explanation of drawings) 7. Contents of amendment (1) Specification On page 13, lines 12 to 14, "Fig. 1 (a) is a sectional view taken along the line l-I" was corrected to "Fig. 1 is a diagram showing an embodiment of the present invention, 2.

Claims (1)

[Claims] 1. A plurality of optical multiplexing/demultiplexing waveguides for multiplexing, demultiplexing, or multiplexing/demultiplexing optical signals of multiple different wavelengths are formed in parallel on the same substrate, and each Each optical signal output section for extracting the optical signal after demultiplexing of the optical multiplexing/demultiplexing waveguide is guided to a different substrate end face for each output wavelength, and is arranged in parallel for each output wavelength. Array type optical multiplexer/demultiplexer. 2. The array type optical multiplexer/demultiplexer according to claim 1, wherein at least one optical signal output portion of the optical multiplexer/demultiplexer waveguide is comprised of a substantially L-shaped curved waveguide. 3. The array type optical multiplexer/demultiplexer according to claim 2, wherein a reflective end face having an angle of approximately 45 degrees with respect to the waveguide direction is formed at the tip of the bent portion of the curved waveguide. 4. The array type optical multiplexer/demultiplexer according to any one of claims 1 to 3, wherein a fiber connector for tape fiber connection is connected to the end face of the cladding layer on which the optical signal output section is provided.