JPH03145605A - Optical fiber connection system - Google Patents

Abstract

PURPOSE:To eliminate decrease in the quantity of light due to a difference in the core diameter of an external cable by specifying the core diameters of repeating cables in a device. CONSTITUTION:When the repeating fiber cables which connect the external optical fiber cable to a transmission and reception module for a light signal is provided, the core diameters of the input and output repeating cables are determined so that gamma i<=gamma max(<)gamma min<=o, where gamma max is the maximum value of the core diameter of the external optical fiber, gamma min the minimum value, gammai the core diameter of a fiber which transmits a signal inputted to the device among repeating optical fibers, and gamma o the core diameter of an output fiber. Consequently, the original performance of the device is satisfied regardless of the core diameters of the optical fibers in use.

Description

[Detailed description of the invention] [Industrial application field] An electronic device that uses optical fiber as a communication path.

[Conventional technology]

Optical fibers have excellent characteristics as information transmission paths, such as low loss and high capacity transmission, and are therefore widely used in computer systems.

Optical fibers are broadly classified into the following types based on their transmission characteristics.

・Multimode (GI type) ・Multimode (SI type) ・Single mode Among these, multimode (GI type) fiber is mainly used in computer systems. However, the fiber itself has a land diameter of 50/125 (μm) and a land diameter of 62.5/125 (μm), respectively.
There are several types, including those (μm). The type of cable to use is determined by the specifications of the device. On the other hand, from a user's standpoint, if there is an optical fiber cable that has already been installed, it is desirable to be able to use that cable. In the case of multimode (GI type) fiber, for example, the connection configuration shown in Figure 1 is 50/125 (μ
m) for devices using optical fibers of 60/1.
When using a 25 (μm) optical fiber, as shown in Figure 2, the original performance of the device (in this case, the transmission distance due to a decrease in light intensity) is reduced due to optical leakage loss at the junction between the device and the optical fiber (external).
The problem arises that the image is damaged.

[Problem to be solved by the invention]

An object of the present invention is to make it possible to satisfy the original performance of the device regardless of the core diameter of the optical fiber used.

[Means to solve the problem]

When optical fibers with different core diameters are connected, the amount of light decreases due to light leakage when light is transmitted in the direction from large to small core diameter, but there is no decrease in the amount of light when transmitted in the opposite direction. Therefore, by determining the core diameter of the relay cable inside the device as shown in FIG. 3, it is possible to eliminate the decrease in light intensity due to the difference in the core diameter of the external cable.

[Example] An example will be described using FIG. 1. Now, in order to enable connection without light leakage to both external optical fibers with core diameters of 50 μm and 62.5 μm, the core diameter of the optical fiber 5a −50 μm is required.
, 6a with a core diameter of -62.5 μm are used to connect the inside of the apparatus. By doing this, the optical transmission between devices 1a and lb is 62.5 μm even if the core diameter is 50 μm.
Whether it is m or not, the relay connector 7a.

There is no fear of light leakage due to the difference in core diameter at 7b.

〔Effect of the invention〕

In general, it is said that the light intensity drop of a multimode (GI type) optical fiber is 2 to 3 dB/Km when the optical wavelength is 0.8 μm. On the other hand, the decrease in the amount of light resulting from light leakage due to the difference in core diameter is estimated to be about 2 dB when transmitting from a core of 62.5 μm to 50 μm, which is close to IKm when converted to the cable length of an optical fiber. That is, according to the present invention, the core diameter of the external optical fiber is 50 μm or 62.5 μm.
Even if it is different, there will be no impact on cable length restrictions due to the reduction in light intensity.

[Brief explanation of the drawing]

Figure 1 is a system configuration diagram of a device that uses optical fibers as a transmission path, Figure 2 is a diagram showing light leakage at a relay connector that connects optical fibers, and Figure 3 is a diagram of the main unit. FIG. 3 is a diagram showing the size relationship of the core diameters of the optical fibers in the device according to the invention. 1〉 Office 1〉 5 Dimensions ratio a: p? 7L Figurero≧Toml desk

Claims (1)

[Claims] 1. When a device uses optical fiber as a communication path and has a relay optical fiber cable that connects an external optical fiber cable to an optical signal transmission/reception module, the maximum core diameter of the external optical fiber is γmax, and the minimum If the value is γmin, the core diameter of the fiber that transmits the input signal to the device among the relay optical fibers is γi, and that of the output fiber is γo, then γi≦γmax(<)γmi
An optical fiber connection method characterized in that the core diameter of the input/output relay table is determined so that n≦γo.