JPH02156747A - Wavelength multiplex optical transmission system - Google Patents

Abstract

PURPOSE:To make the scale of a line concentration system small, to adopt N sets for number of wavelengths of a transmission light signal of an optical transmitter and to attain wavelength synthesis of N sets of wavelengths by dividing plural optical transmitters into two groups and inputting the optical outputs of each optical transmitter group to the 1st and 2nd terminal groups of a star coupler. CONSTITUTION:The multiplexed optical signal of a 1st optical transmitter group 1A passes through the optical fiber 8d of a star coupler 8 and is outputted to a 2nd terminal group 8e. Moreover, the multiplexed optical signal of a 2nd optical transmitter group 1B passes through the optical fiber 8b of a star coupler 8 and is outputted to a 1st terminal group 8a. Then an optical signal demultiplexed into the transmission optical wavelength of an optical transmitter 1 by optical demultiplexers 5A, 5B is propagated through an optical fiber 6, inputted to each light receiving device 7 of a 1st light receiving device group 7A and a 2nd light receiving device group 7B where photoelectric conversion is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wavelength division multiplexing optical transmission system that multiplexes and transmits optical signals using a star coupler.

[Conventional technology]

Figure 3 shows 9For example, H, Kobrinaki, De
Monstration of HLgh Capaci
Ty in The LAMBDANT Archit
ecture: A Multiwavelength
0ptical Network.

Ii:l, electronics Letters 30
th July 1981 Vol.

2341B is a diagram showing the conventional wavelength division multiplexing optical transmission system shown in FIG. (2) is a 2N optical fiber provided corresponding to the optical transmitter il+, and (3) is a 2N optical fiber.
A star coupler (hereinafter abbreviated as [2NX1:] Star Cub) is provided with N input terminals (3a) and one output terminal (3e), and this star coupler has an optical fiber (3b) inside and these optical fibers. A mixer section (3C) that combines optical signals guided by a fiber (3C) and a mixer section (3C) that combines optical signals guided by a fiber (3C);
It consists of an optical fiber (3d) that guides the optical signal multiplexed in C) to an output terminal (3e). (4) is an optical fiber connected to the output terminal (3e) of the star coupler (3), and (5) is a demultiplexer that demultiplexes the optical signal guided by this optical fiber into an optical signal of the original wavelength. The splitter (6) is a 2N optical fiber (7) connected to the splitter (5).
) is an optical receiving device that receives an optical signal of a wavelength corresponding to the optical transmitting device, and is connected to the optical fiber (6).

FIG. 4 is an explanatory diagram of the operation of the star coupler (3).

Next, the operation will be explained. In fig.

Optical signals with mutually different wavelengths transmitted from 2N optical transmitters+11 are sent to a star coupler (
3) reaches the input terminal (3a). This signal is.

The optical fiber (3b) in the star coupler (3) leads to the mixer section (3c) and is multiplexed at the mixer section (3c).The multiplexed optical signal is sent to the optical fibers (3d) and (4).
is manually applied to the duplexer (5). The demultiplexer (5) demultiplexes the light into optical signals with wavelengths corresponding to the wavelength of the transmitted light. Duplexer (
The output optical signal of step 5) is inputted to an optical receiving device (7) through an optical fiber (6) and converted into a photoelectric signal.

Here, the operation of the star coupler will be conceptually explained below based on FIG. 4, taking a slab type star coupler as an example (2NX1). The optical signal input to the star coupler is transmitted through the optical fiber (3b) and radiated into the mixer section (3c). The optical signal power of each wavelength becomes almost uniform at the end face A of the mixer section (5c), and the combined optical signal is output after being transmitted through the optical fiber (3d).

[Problem to be solved by the invention]

By the way, since the conventional wavelength division multiplexing optical transmission system is configured as described above, to configure a concentrator system, it is necessary to use a star coupler having the number of input terminals equal to the number of wavelengths to be multiplexed, or to connect more input terminals. There is a problem that a plurality of star couplers, which are small in number, must be used, and the concentrator system becomes large and expensive. Further, when the optical transmitter is configured with one star coupler, 2N wavelengths of transmission signals of the optical transmitter are required, and there is a problem that the wavelengths must be different from each other.

This invention was made to solve the above-mentioned problems, and uses a (N+1)X[N+11 star coupler to make the concentrator system smaller.

It is an object of the present invention to provide a wavelength multiplexing optical transmission system that can perform multiplexing of N wavelengths and multiplexing of N wavelengths by increasing the number of wavelengths of optical signals transmitted by an optical transmitter to N.

[Means to solve the problem]

In the wavelength division multiplexing optical transmission system according to the present invention, a first optical transmitter group is connected to a plurality of specific terminals of a first terminal group of a star coupler, and a first optical transmitter group is connected to a plurality of specific terminals of a second terminal group of a star coupler. 2
A group of optical transmitting devices are connected.

The first and second optical receiving device groups corresponding to the optical wavelengths of the first and second optical transmitting device groups are transmitted from terminals other than specific terminals of the first and second terminal groups via a demultiplexer. It is connected.

[Effect]

The wavelength division multiplexing optical transmission system in this invention is:

Due to the directional coupling property of the star coupler, optical signals inputted to a plurality of specific terminals of the first and second terminal groups are multiplexed in the mixer section without mutual interference, and are then sent to the second and first terminal groups. is connected to the terminal of

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, CIA) is a first optical transmitter group consisting of N optical transmitters with different transmission wavelengths, and (IB) is a second optical transmitter group consisting of N optical transmitters with different transmission wavelengths. The transmitter group (8) is a star coupler (hereinafter referred to as C60) equipped with N+1 input terminals (first terminal group) (8a) and N-)-1 output terminals (second terminal group) (C60). [N+
1)x[:N+1]starcube), this star coupler has an optical fiber (8b) inside and a mixer section (8c) that multiplexes the optical signals guided by these optical fibers (8b).

The optical signal multiplexed by this mixer section (8c) is output to the output terminal (
It consists of an optical fiber (8d) that leads to 8e).

Each optical transmitter 11) of the first optical transmitter group (1A)
The outputs of are connected to N input terminals (8a) of the star coupler (8) by H optical fibers (2), and are connected to each optical transmitter 11+ of the second optical transmitter group (1B).
The outputs of are connected to N output terminals (8e) of the star coupler (8) by N optical fibers (2).

(5A) is a demultiplexer having demultiplexing characteristics corresponding to the transmission light wavelength of the first optical transmitter group (1A).

(5B) is a demultiplexer having demultiplexing characteristics corresponding to the wavelength of the transmitted light of the second optical transmitter group (1B). These splitters (5A) and (5B) connect the optical fiber (4) with
and is connected to the input terminal (8a) and output terminal (8θ) of the star coupler (8).

(7A) are N optical receivers (7) that receive light wavelengths corresponding to the wavelengths of light transmitted by the first optical transmitter group (1A);
(7B) is a first optical receiving device group consisting of N optical receiving devices that receive an optical wavelength corresponding to the transmitted light wavelength of the second optical transmitting device group (IB). This is a group of optical receivers. These optical receiver groups (IA) and (
IB) are each connected to the demultiplexers [5A] and (5B) by N optical fibers (61).

FIG. 2 is an explanatory diagram of the operation of the (N+1)X[N+1] star coupler, and shows a slab type star coupler as an example. In FIG. 1, the same parts as those in the conventional example in FIG. 3 are given the same reference numerals, and the description thereof will be omitted as appropriate. Next, the operation will be described. First optical transmitter group (1A
), and each optical transmitter il+ of the second optical transmitter group (1B
), each optical transmitter fi+ converts an input electric signal (not shown) into an optical signal with a different wavelength set in each optical transmitter 111 and outputs it. Each optical signal output of the transmitter group (1A) is connected to an optical fiber (2
) and enters the N input terminals (8a) of the first terminal group of the star coupler (8). Each optical signal output of the second optical transmitter group (1B) propagates through the optical fiber (2) and is input to N output terminals [8e] of the second terminal group of the star coupler (8). The optical signals of the first optical transmitting device group (IA) and the second optical transmitting device group (1B) input to the star coupler (8) propagate through optical fibers (8b) and (8d) to the mixer section. (8C), multiplexing is performed for each optical transmitter group. The multiplexed optical signals of the first optical transmitter group (1A) are output to the optical fiber (8d). On the other hand, the multiplexed optical signals of the second optical transmitter group (1B) are transmitted through optical fibers (8
b) is output.

As mentioned above, the star coupler (8) receives optical signals from the first terminal group and the second terminal group, and the star coupler (8)
), the optical signals of the optical transmitter group propagate in opposite directions, but do not affect each other.

Also, the optical signal input manually to the optical fiber (8b).

Due to the unidirectional diffusivity of the mixer section (8C), it is not coupled to other optical fibers (8b) in principle. Similarly.

In principle, the optical signal input to the optical fiber (8e) is not coupled to another optical fiber (8e).

The multiplexed optical signal of the first optical transmitter group (IA) is
Optical fiber (8d) of star coupler (8)? street number 2
is output to the terminal group (8e). Further, the multiplexed optical signals of the second optical transmitter group (1B) are transmitted through optical fibers (8
b)? The signal is output to the first terminal group (8a). These multiplexed optical signals are transferred from the terminals (8a) and (8e) of the first and second terminal groups of the star coupler (8) that are not connected to the transmitter group to the optical fiber (4).
Therefore, the demultiplexers (5A) and (5B), which have wavelength characteristics that demultiplex the wavelengths corresponding to the first transmitting device group (1A) and the second transmitting device group (1B), respectively, are manually operated. The optical signals demultiplexed by the demultiplexers (5A) and (5B) into the transmission light wavelengths of the respective optical transmitters il+ propagate through the optical fibers (6) and are sent to the first optical receiver group. (7A)
and the second optical receiver group (7B) are also manually inputted to the optical receiver (7) and subjected to photoelectric conversion.

The operation of the (N+1)x[N+1] star coupler (8) will be explained based on FIG.

The light beam emitted from the optical fiber (8b) into the mixer section (8C) not only propagates inside, but also propagates while being reflected at the upper and lower and left and right boundary surfaces of the mixer section.

At the end face A of the mixer section (8C), the optical signal power of each wavelength becomes almost uniform, and the combined optical signal is output through the optical fiber (8d). Similarly, optical fiber (8d)
Light beam % radiated into the mixer section (8C) from FF
The light propagates through the mixer section (8C) while being reflected at the upper and lower and left and right interfaces.

At the end face B of the mixer section (8), the optical signal power of each wavelength becomes almost uniform, and the combined optical signal is output through the optical fiber (8b).

By the way, regarding the embodiment shown in FIG.

Each optical signal of the first optical transmitter group (1A) is multiplexed by a star coupler (8), and then connected to a terminal (8e) and an optical fiber (2
), it reaches each optical transmitter 11+ of the second optical transmitter group [1B], but if the number of optical pharons in the star coupler (8) is large, the amount of coupled light is small, which affects the optical transmitter operation. There isn't. In addition, each optical signal of the second optical transmitting device group (1B) also passes through the optical fiber (8b) and the optical fiber (2) to each optical transmitting device 11) of the first optical transmitting device group (1A). However, there is no effect on the optical transmission operation.

In addition, in the embodiment shown in FIG. 1, the transmission light wavelength of the optical transmitter (1) of the first optical transmitter group (1A) and the optical transmitter +11 of the second optical transmitter group (1B) are As long as the transmission wavelengths are different in the optical transmitter group, the unidirectional diffusivity of the star coupler (8) described above prevents interference between the same wavelengths propagating through transmission systems with different routes. Therefore, it does not matter if all the wavelengths are the same or the wavelengths are the same among the optical transmitting devices group.

In addition, by using two 8-wave demultiplexers, it is possible to use a narrower wavelength demultiplexer instead of one that requires broadband wavelength demultiplexing characteristics. It is also possible to use one with the same wavelength demultiplexing characteristics.

In addition, in the embodiment shown in Fig. 1, the slab type star coupler shown in Fig. 2 is shown as the star coupler (8), but the same effect can be obtained when applied to a fiber fusion type star coupler. play.

〔Effect of the invention〕

As described above, according to the present invention, a plurality of optical transmitters can be
Since the optical output of each optical transmitter group is divided into two groups and is configured so that the optical output of each optical transmitter group is manually applied to the first and second terminal groups of the star coupler, if the optical transmission wavelengths in the same group are different, It is possible to use the same optical transmission wavelength between groups, and by combining the wavelengths for each group, it has the advantage of being smaller and cheaper than conventional systems.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a wavelength division multiplexing optical transmission system according to an embodiment of the invention, and FIG. 2 is an explanatory diagram of the operation of a star coupler according to the embodiment of the invention. FIG. 3 is a block diagram showing the configuration of a conventional wavelength division multiplexing transmission system, and FIG. 4 is an explanatory diagram of the operation of a star coupler in the conventional system. In the figure, (11 is optical transmitter + CIA) #(IB
) is an optical transmitter group, i3), (8) is a star coupler, (3c). (8C) is the mixer part, (fi), (5A),
(5B) is a duplexer. (7) is an optical receiver, and (7A) and (7B) are a group of optical receivers. In addition, in FIG. 1, the same reference numerals indicate the same or equivalent parts. Figure 2

Claims (1)

[Claims] a transmission star coupler having a first terminal group and a second terminal group; and a first optical transmitting device group connected to a plurality of specific terminals of the first terminal group and outputting optical signals of different wavelengths. a second optical transmitter group that is connected to a plurality of specific terminals of the second terminal group and outputs optical signals of different wavelengths; and a plurality of specific terminals of the first and second terminal groups. The first and second
What is claimed is: 1. A wavelength division multiplexing optical transmission system comprising first and second optical receiving device groups connected in correspondence with the optical transmitting device group.