JPS5923643A - Optical transmission line controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application In recent years, with the development of optical communications, so-called data ways have been developed in which signals are transmitted by connecting terminals in a loop with optical fibers. The present invention is used at the terminal of a loop-shaped dataway, and relates to an optical transmission line control device that couples light that has passed through an optical fiber to a predetermined optical fiber for transmission.

Conventional configuration and its problems In a loop dataway that uses wavelength division multiplexing bidirectional transmission and has an optical bypass at the terminal, even if the optical fiber is cut due to an accident at one point or the power supply at the terminal fails, the data in the opposite direction cannot be used. There is an advantage that data can be sent by transmission or bypass. FIG. 1 shows the configuration of a wavelength multiplexed bidirectional dataway with optical bypass. Optical fiber ea is used between terminals 1 to 4.
,eb.

They are connected by 6C++6d, and the light with the wavelength λ1 is transmitted clockwise, and the light with the wavelength λ2 is transmitted counterclockwise.

If bidirectional transmission is performed in this way, even if fiber 6b is cut due to an accident, for example at point 6e, data transmission between terminals 2 and 3 will continue.
4-41-2 is sufficient.

Each of the terminals 1 to 4 has a component that operates when the power supply fails to provide optical bypass. For example, the component 6 in the terminal 3 normally has fibers 6b and 7C and fibers 7d and 60 in a coupled state for light of wavelength λ1, and still has fibers 6b and 7b and fibers 7b and 60 coupled for light of wavelength λ2. Fibers 7a and 60 are in a coupled state. However, if the power source of the terminal 3 fails or the light emitting element or light receiving element deteriorates, the fibers 6b and 60 are bypassed.

One of the inventors of the present invention proposed a component that integrates two duplexers and an optical switch in Japanese Patent Application No. 56-126674. Its configuration is shown in FIGS. 2 and 3.

In Figures 2 and 3, 8 to 14 are optical fibers arranged in a hexagonal dense manner, with 8 being the first, 9 being the second, 1° being the third, and the 11th being the optical fibers.
is the fourth fiber, the 13th fiber is the fifth fiber, and the 14th fiber is the sixth fiber. 1
2 are idle fibers and are not used. One ends of these fibers 8 to 14 are bonded near the focal plane of a focusing rod lens 16 with a period length of approximately h.

A mirror 17 at the other end of the lens 16 can be moved up and down. The filter 18 is a long wavelength transmission filter (LWP F) that reflects light with wavelength λ1 and transmits light with wavelength λ2.
), when the mirror 1 is not between the lens 16 and the filter 18, the wavelength λ1 incident from the first fiber 8
When the light is reflected by the filter 18, it passes through the third fiber 10.
The filter 18 is fixed at an angle oblique to the optical axis of the lens 16 so that the light is incident on the lens 16. In this way, it can be assumed that the optical axis is between phino (8 and 11) (hereinafter,
(referred to as the optical center for the LWPF), the fibers 11 and 9 are symmetrical with respect to this optical center.

Then, the light having the wavelength λ1 that has entered from the fourth fiber 11 is reflected by the filter 18 and enters the second fiber <9. In addition, a short wavelength transmission filter (SWPF) 16 is formed between the lens 16 and the phinograph (10° 11) in order to prevent light of wavelength λ2 from entering. The light with wavelength λ2 passes through the filter 18 and is reflected by the mirror 19 to the fifth fine nozzle (1
The mirror 19 is fixed at an angle oblique to the optical axis of the lens so that the light enters the lens. In these various structures, it can be assumed that the optical center for the mirror 19 is located between fibers 9 and 13.
It is symmetrical with 3. Then, the light of wavelength λ2 incident from the sixth fiber 14 passes through the filter 18 and is reflected by the mirror 1.
9 and enters the first fiber 8.

Next, considering the state in which the second mirror 17 is inserted between the lens 16 and the filter 18, fibers 8 and 9 are in a coupled state since phi/<8.9 is at a symmetrical position with respect to the lens axis and the mirror is perpendicular to the axis. Therefore, the light from the fiber 8 enters the phino (9). Conversely, the light incident from the fiber 9 enters the phino ζ 8. Note that even if the long wavelength transmission filter 18 and the short wavelength transmission filter 16 are reversed, It can be configured similarly.

A specific usage example of such an optical transmission line control device is shown in FIG. 4 below. The optical transmission line control device 2o is shown in FIG. 2, and includes fibers 8, 9, and 11.

13 and 14 are the same as the fin in Figure 2. First, fibers 8 and 9 are trunk fibers in a dataway, and light beams of wavelengths λ1 and λ2 are transmitted bidirectionally. The light of wavelength λ1 entering from fiber 8 is transmitted to fiber 1o.
and is converted into an electrical signal. Further, the signal from this terminal is converted into an optical signal, enters the fiber 11, passes through the optical transmission line control device 2o, and enters the trunk fiber 9. On the other hand, the light of wavelength λ2 incident from fiber 9 is transmitted to fiber 13.
The signal light enters the main fiber 8 and is converted into an electrical signal, and the signal light from the fiber 14 enters the main fiber 8. In this way, two waves of optical signals can be relayed by one optical path control device 20.

If this terminal is not used, mirror 1 in FIG.
7 is inserted between the lens 16 and the filter 18, the second
The trunk fibers 8 and 9 shown in the figure are connected directly, and data transmission between other terminals can be performed without relaying through this station.

However, in the structure of the fiber bundles 9 to 14 as shown in FIG. 3, the input and output fibers 10 and 1 for light of wavelength λ1
1 are adjacent to each other, a portion of the light having the wavelength λ1 incident from the fiber 11 leaks into the fiber 10. This kind of leakage corresponds to the leakage from fiber 11 to fiber 1o within terminal 2° in Figure 4, which means that the transmitted signal mixes with the received signal of the own station, resulting in S/N deterioration. It causes

This phenomenon also occurs in the relationship between the input/output fibers 14 and 13 of wavelength λ2.

OBJECTS OF THE INVENTION The present invention provides an optical transmission line control device that eliminates the above-mentioned disadvantage of interference within the same wavelength.

Structure of the Invention The optical composite component according to the present invention consists of a fiber bundle in which six optical fibers are arranged in a straight line, and fibers for transmitting light of the same wavelength are arranged so that fibers for receiving light are not adjacent to each other.

DESCRIPTION OF EMBODIMENTS FIG. 5 shows the structure of a fiber bundle according to an embodiment of the present invention. Fibers numbered the same as those shown in FIGS. 3 and 4 perform the same function. When this fiber bundle is used in a composite part, the LWPFls are glued so that the optical center for the LWPF 18 is the center 21 of the fibers 9 and 11, and the mirror 19 is glued so that the optical center for the mirror 19 is the center 22 of the fibers 8 and 14. Glue. In optical composite components using fiber bundles with this structure, the input and output fibers of the same wavelength (11 and 10 at wavelength λ1) are separated by one fiber, so it is possible to reduce the leakage of light of the same wavelength. can.

FIG. 6 shows another embodiment according to the present invention.

Fibers with the same numbers as those shown in FIGS. 3 and 4 function in a similar manner. In the optical composite component using this fiber bundle, the optical centers of LWPFlB, mirror 19, and mirror 17 are each arranged at 21°22.23°. When using the fiber bundle shown in Figure 6, the input and
Since the output fibers (11 and 10 at wavelength λ1) are separated by two fibers, leakage of light of the same wavelength can be further reduced.

Fibers 8, 9, 11, 12, and 14 are graded index fibers with a core diameter of 50 μm.

When step-index fibers with a core diameter of 80 μm are used for the fibers 10 and 13, the rate at which light with wavelength λ2 incident from the fiber 14 leaks into the fiber 13 is:
-37 dB and -41 dB for fiber bundles with structures shown in Figures 3, 5, and 6, respectively.

-4edB.

As described in detail, the present invention provides an optical composite component in which input and output fibers can be easily separated by arranging six fibers in a straight line, thereby reducing leakage of light of the same wavelength. can be provided.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a bidirectional dataway with optical bypass, Figure 2 is a configuration diagram of optical composite components, Figure 3 is a layout diagram of a conventional fiber bundle, and Figure 4 is data using optical composite components. The configuration diagram of a part of the way, FIG. 5, and FIG. 6 are respectively layout diagrams of fiber bundles in an optical transmission line control device according to an embodiment of the present invention. 8.9,10,11.13.14...Optical fiber, 15...Lens, 16...Filter, 17...Mirror, 18... ...Filter, 19...Mirror.

Claims (1)

[Claims] A converging rod lens having a periodic length of approximately 1.5 mm is provided, and the refractive index decreases toward the outside. Second. Third. 4th. Fifth. A sixth six optical fibers are arranged in a straight line, and the first, second, and sixth optical fibers are arranged on the focal plane of the focusing rod lens. Third. 4th. 6th. 6th 6
The end faces of two optical fibers are coupled together, and a long wavelength or short wavelength transmission filter is placed on the other end side of the focusing rod lens at an angle with respect to the optical axis of the focusing rod lens, and the reflection is reflected by the transmission filter. The first optical fiber 7 and the third optical fiber are connected to each other, and the second optical fiber and the fourth optical fiber are connected to each other, and the optical axis is connected behind the transmission filter. A mirror is arranged to be inclined relative to the transmission filter, so that the second optical fiber and the fifth optical fiber are connected to each other, and the first optical fiber and the sixth optical fiber are connected to each other with respect to the light transmitted through the transmission filter. Coupled state and t1 A mirror is installed between the other end surface of the focusing rod lens and the transmission filter so as to be freely retractable, and when this mirror is present between the focusing rod lens and the transmission filter, the first optical fiber and the second optical fiber are in a coupled state, and at least the third optical fiber and the fourth optical fiber and the fifth optical fiber and the sixth optical fiber are not adjacent to each other. Optical transmission line control device.