JPH03210846A - Optical communication equipment - Google Patents

Abstract

PURPOSE:To make an optical communication equipment itself small remarkably by forming a waveguide type branching filter array on one board. CONSTITUTION:A branching device 30 consists of a waveguide type branching filter array. A branching filter array 30 are made up of 4 optical branching elements 100a, 100b, 100c and 100d on one board 90. Let a pitch interval S for core guide paths 91 be 0.25mm, then the width W is 2.5mm when the four optical branching elements are used and the length l is nearly 20mm even when a length required for the directional coupler is taken into account and the branching device array 30 with a very small size is realized. Even when number of subscribers is 100, the width and the length of the waveguide branching array 30 are realized nearly as 30mm and 20mm.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical communication device, and particularly to a small and economical optical communication device.

[Prior Art] Recently, high-speed, wideband network systems have been developed that include a system for bidirectionally transmitting telephone, data, video information, etc. between subscribers, and a system for distributing and transmitting video information such as TV, HDTV, etc. to each subscriber. Research is progressing to make this possible through optical fiber communications.

FIG. 4 shows a conventional example of the above-mentioned optical fiber communication system (Japanese Unexamined Patent Publication No. 64-37132).

In this system, bidirectional communication between subscribers 1 and 2 uses an optical signal of wavelength ^1, and includes an optical fiber 21, an optical demultiplexer 31, an optical exchange 40, an optical demultiplexer 32, and an optical fiber 22. It is done through. On the other hand, the broadcast signals distributed and transmitted to each subscriber 1.2 have wavelengths λ21 slightly different from each other.
．． Using an optical signal of λ22, it is sent from an optical transmitter 61.62 to each subscriber 1.2 via an optical star coupler 5o, each optical demultiplexer 31.32, and an optical fiber 21.22. Each subscriber uses the above wavelength ^21. Broadcast signals are received by selectively tuning the λ22 optical signal.

[Problems to be Solved by the Invention] The above conventional example describes a case where the number of subscribers is two, but if this is attempted to be realized in a case where the number of subscribers is several dozen or more, the following problems arise. was found to occur. (1) Optical demultiplexers are required for each number of subscribers, but dozens or more of the above individual optical demultiplexers can be installed! In this case, the device itself becomes very large. (g + Therefore, it becomes economically expensive. (3) The number of output ports of the optical star coupler 50 is also required to correspond to the number of subscribers, but it is necessary to increase the distribution loss and excess loss of the optical star coupler. Invitation,
It becomes impossible to maintain a long span distance to subscribers 1 and 2.

Therefore, it is virtually impossible to increase the number of subscribers.

An object of the present invention is to solve the above problems and provide a small and economical optical communication device.

[Means for Solving the Problems] The optical communication device of the present invention performs two-way communication between each subscriber using an optical signal with a wavelength λ1 via an optical fiber, an optical demultiplexer, and an optical switch. In an optical communication device that transmits a distributed signal from a plurality of optical signals in the wavelength λ2 band to each subscriber via an optical star coupler, the optical demultiplexer, and the optical fiber, one optical demultiplexer is used as the optical demultiplexer. This uses a waveguide type duplexer array constructed on a substrate. This waveguide type demultiplexing array preferably has a configuration in which a plurality of directional coupler type demultiplexing elements are arranged in parallel.

Further, at least one of the optical star coupler, the optical fiber, and the waveguide type splitter array is made of a material containing rare earth element ions, and at least one of the input ports of the optical star coupler is connected to the rare earth element ion. In this case, it is more preferable that at least one of the optical star coupler, optical fiber, and waveguide type demultiplexer array be made of Er and Nd rare earth elements. It is composed of a material containing elemental ions and F.

In addition, in a configuration in which a waveguide type demultiplexer array is configured on the above-mentioned two substrates, or in a configuration in which the duplexer array is configured by arranging directionally coupled demultiplexing elements in parallel, the waveguide type demultiplexer array is Among the optical fibers that are connected at one end to the output port of the optical fiber array, the color of the outer peripheral surface of the optical fiber that is connected to the optical switch at the other end, and the optical fiber that is connected to the optical star coupler at the other end. It is good to make them different from each other.

[Operations] Since the optical demultiplexers are arranged as an array on one substrate, the desired optical communication device can be constructed in an extremely small size even when the number of subscribers is several tens or more. Furthermore, compared to the case where individual duplexers are provided, an optical communication device provided with a duplexer array has a structure that is easier to mass produce, and can significantly reduce costs. It is preferable to configure the waveguide type duplexer array by providing directional coupling type demultiplexing elements in parallel.

Additionally, if the optical star coupler, optical fiber, or waveguide type splitter array is constructed of a material containing rare earth element ions, the rare earth element will be excited by the excitation light incident from the input port of the optical star coupler. , the optical signal in the wavelength λ2 band is amplified, making it possible to compensate for optical loss and further extend the transmission distance. When the optical star coupler, optical fiber, or waveguide type demultiplexer array is constructed of a material containing Er and Nd rare earth ions and F, optical signals in two wavelength bands λ1 and λ2 are amplified. This allows the transmission distance to be further extended.

In addition, by making the outer peripheral surfaces of the optical fibers connected to the optical exchanger and the optical fibers connected to the optical star coupler different in color, they can be easily identified. The work efficiency is also improved for the connection work of the device array.

[Example] Hereinafter, an example of the present invention will be described based on the accompanying drawings.

FIG. 1 shows an embodiment of an optical communication device of the present invention.

This embodiment has a configuration suitable for a case where the number of subscribers is three or more, preferably from several tens to over a hundred.

Each subscriber 1, 2..., n and the station 70 that provides both broadcasting and communication services are connected via optical fibers 21, 22...2.
A branching filter 30, an optical switch 40, and an optical star coupler 50 configured according to the number of subscribers n are provided in the 0 station 70 connected by n.

Also, within the station 70, broadcast-type video information is transmitted at wavelengths λ, 8, . λ■,...λ2. An optical transmitter array 60 is provided which converts the signal into an optical signal and sends it to the input port of the optical star coupler 50.

A feature of this embodiment is that the duplexer 30 is constituted by a waveguide type duplexer array. As this duplexer array 30, for example, one having the configuration shown in FIG. 2 is used. The demultiplexer array 30 shown in FIG. 2 includes four optical demultiplexing elements 100a, 1 on one substrate 90.
00b, tooc, and 100d. That is, a cladding layer 92 and a plurality of core waveguides 91 embedded in the cladding layer 92 are formed on one substrate 90.
A pair of core waveguides 91.9 adjacent to each other forming a
1, the optical demultiplexing elements 100a, 100b, 100c, each having a directional coupler structure can be formed.
100d are arranged in parallel in an array. If the pitch interval S for arranging the core waveguides 91 is set to 0.25+em, in the case of this example where there are four optical demultiplexing elements, @W is 2.
5 ml, and the length O is approximately 20 u even considering the length required for a directional coupler, making it possible to realize a very small duplexer array 30. Even when the number of subscribers n is 100, the width and length of the waveguide type demultiplexer array 30 are approximately 3
It can be realized with a small size of 01m and approximately 20ml1.

Further, this waveguide type demultiplexer array 30 can be easily mass-produced by processes such as CVD glass deposition on the substrate 90, photolithography, dry etching, cladding film formation, cutting, and polishing. A significant cost reduction can be expected. By using a substrate 90 with a diameter of 3 inches, it is possible to realize a duplexer array 30 that can accommodate several hundred subscribers. Moreover, when manufacturing such a demultiplexer array 30, individual optical demultiplexing elements 100a,
The characteristics of 100b, . . . can also be made uniform.

Now, returning to FIG. 1, each subscriber 1.
(n) optical fibers 21゜22,...2n from 2
is connected. Correspondingly, 2n optical fibers 71...7n, 81°...8n are connected to the output port of the duplexer array 30 (at the right end in FIG. 2(B)).

These 2n optical fibers 71, . . . 7n, , 81 .・
...8n, n optical fibers 71.72. ...
7n between the demultiplexer array 30 and the charge exchanger 40, and the remaining n optical fibers 81, 82 . ...8n are respectively connected between the demultiplexer array 30 and the output port of the optical star coupler 50.

Next, transmission of communication type and broadcast type information will be explained using the configuration shown in FIG. Bidirectional optical communication between each subscriber 1 to n uses an optical signal of wavelength λl (for example, λ, = 1.3 μs), and includes optical fibers 21 to 2n, a waveguide type demultiplexer array 30, and an optical fiber 71. 72, . . . 7n, through the optical switch 40.

On the other hand, broadcast video information has wavelengths λ that are slightly different from each other.
21”+λ3s,...,λ2. (For example, wavelength λ2
= 1.5μ-band) optical signal, optical transmission 8!61°6
2. ..., optical signals are sent from 6p, optical star coupler 50, optical fibers 81, 82 . ...8n, the waveguide type demultiplexer array 30, and the optical fibers 21.22...2n to each subscriber 1.2. ..., sent to n.

And each subscriber 1.2. . . . n, the optical signal of the desired wavelength is tuned to selectively receive the video information channel.

As described above, according to this embodiment, by providing the optical demultiplexing elements 100a and 100b for the number of subscribers n on one substrate 90, the structure in which optical demultiplexers are individually provided as in the conventional example is improved. It can be expected to be significantly smaller, more economical, and higher in performance than the previous model. Moreover, the optical demultiplexing elements 100a, 100
By providing b... in an array, the structure becomes easy to mass produce, and since mounting and processing can be done all at once, costs can be reduced.

FIG. 3 shows another embodiment of the optical communication device of the present invention. This optical communication device compensates for optical loss within each optical component and optical coupling loss between each optical component, and
. That is, the optical fibers 21R, 22R,...
2nR waveguide type demultiplexer array 30R1 optical 7 fibers 71.
-7n, 81°...8n and optical star coupler 50R
are each made of a glass material doped with rare earth element ions, and one extra input port of the optical star coupler 50R is provided, and the light of the excitation light semiconductor laser 101 for exciting the rare earth element ions is provided from this input port. (wavelength λ,) is incident, and wavelength λ21 . λ22
,...λ2. It is designed to amplify the optical signal of. For example, when Er ions are used as the rare earth element ions, the wavelength λ1 of the semiconductor laser 101 is 0.
．． 53μm, 0.67μm, 0.8μm, 0.98μm
Alternatively, either 1.48μ- is used. In addition to the above Er, rare earth element ions include Nd, Sr, and Yb.
, Ho, Tm, or the like is used. t, wavelength λ, = 1.3μ intestinal optical signal and λ, = 1.5μm band (λ2++ λ12...λ1
．． When amplifying optical signals in common, the optical fibers 21, 22R, .
This can be realized by using a glass material containing iron.

According to this embodiment, it is possible to realize a small and economical optical communication device, and even when the number of subscribers n is 100 or more, the transmission between the subscribers 1, 2...n and the station 70 is Communication can be performed over a sufficiently long distance.

In addition, in the configuration of FIG. 3, the optical fibers 71R, 72
Rare earth element ions do not need to be added to R, = -7nR, 81R, 82R- and -8nR, and two or more semiconductor lasers for excitation light may be connected to the input port of the optical star coupler 50R. In this case, the degree of amplification can be made even higher. However, the wavelengths of these two or more semiconductor lasers for pumping light may be made to differ from each other. In this case, a pumping light source having a wavelength with high pumping efficiency for the wavelength λ, (1,3μ-) (for example, 0.514μm
) and a wavelength λ2 band (1,5μ-band) with a high excitation efficiency wavelength excitation light source (for example, 1.48μ fog) can be used. Further, the optical star coupler 50R may be either a waveguide type or an optical fiber type.

In addition, optical fibers 71R, 72R, .
R, 82R, . ...7n.

81, . . 8n for connection to the optical exchange@40 and those for connection to the optical star coupler 50R can be easily distinguished, and the optical fibers 71 . ...7n, 8
1. ...8n connectivity will be dramatically improved.

[Effects of the Invention] In summary, according to the optical communication device of the present invention, since the waveguide type demultiplexer array is configured on one substrate, the optical communication device itself can be significantly miniaturized, and the cost can be reduced. It is economically advantageous because it can reduce costs.

Furthermore, in conventional equipment, when the number of subscribers exceeds several tens, not only does the distribution loss and excess loss of the optical star coupler increase, but also the optical loss of other optical components and the optical coupling loss between each optical component. However, according to the optical communication device of the present invention, the rare earth element is excited and the propagating optical signal is amplified, thereby compensating for optical loss and reducing the transmission distance. can be further extended.

In addition, by changing the color of the outer peripheral surface of the optical fibers in the office, it is possible to easily distinguish between the optical fibers connected to the optical exchange and the optical fibers connected to the optical star coupler.
The workability of these connections becomes easier.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an optical communication device according to an embodiment of the present invention, and FIG. 2 is a diagram showing an example of a waveguide type optical demultiplexer array used in the optical communication device according to an embodiment of the present invention. Figure 3
The figure shows an optical communication device according to another practical example of the present invention,
FIG. 4 is a diagram showing a conventional optical communication device. In the figure, 1, 2. ...n is subscriber, 21, 22 . ...
2n is an optical fiber, 30 is a waveguide type optical demultiplexer array, 4
0 is an optical switch, 50 is an optical star coupler, 60 is an optical transmitter array, 70 is a station, 71, 72°...72n, 81,
82. ...8n is the optical fiber 90 is the substrate, 91 is the core waveguide, 92 is the cladding layer, 100a, ...100d
101 indicates an optical demultiplexing element, and 101 indicates a semiconductor laser.

Claims (1)

[Claims] 1. Two-way communication is performed between each subscriber using an optical signal with a wavelength λ_1 via an optical fiber, an optical demultiplexer, and an optical switch, while a distributed signal from the station is transmitted with a wavelength λ_2 band. In an optical communication device that uses a plurality of optical signals and sends them to each subscriber via an optical star coupler, the optical demultiplexer, and the optical fiber, a waveguide type demultiplexer is constructed on one substrate as the optical demultiplexer. An optical communication device characterized by using a device array. 2. The optical communication device according to claim 1, wherein the waveguide type demultiplexing array is constructed by arranging a plurality of directional coupler type demultiplexing elements in parallel. 3. The optical communication device according to claim 1, wherein at least one of the optical star coupler, the optical fiber, and the waveguide type demultiplexer array is made of a material containing rare earth element ions,
An optical communication device characterized in that excitation light for exciting the rare earth element ions is made to enter at least one of the input ports of the optical star coupler. 4. The optical communication device according to claim 3, wherein at least one of the optical star coupler, the optical fiber, and the waveguide type demultiplexer array is made of a material containing Er and Nd rare earth element ions and F. An optical communication device characterized by: 5. The optical communication device according to claim 1 or 2, wherein one end of the optical fiber is connected to the output port of the waveguide type demultiplexer array, and the other end of the optical fiber is connected to the optical exchanger. An optical communication device characterized in that the outer peripheral surface of the optical fiber connected to the optical star coupler has a different color.