JPS5915915A - Optical distributor - Google Patents

Abstract

PURPOSE:To realize an optical distributor having the characteristic that an optical signal is not outputted to the output terminal of the port to which the optical signal is supplied by using a reflection plate group wherein plural pieces of reflection plate having transmission surfaces and reflection surfaces for light are held at prescribed inclinations. CONSTITUTION:An optical distributor 20 has, for example, four ports 21-24, and optical fibers 31-34, 43-44 are connected at the end parts M1, M2, T1, T2 of the input opticl fibers and the end parts M'1, M'2, R1, R2 of the output optical fibers to the respective ports. The end parts of the respective optical fibers are connected with a circular cylindrical rod lens 35 to a reflection plate group 45 consisting of four sheets of light reflection plates 50-53. The optical signal emitted from the part M2 of, for example, the 2nd port 22 is made incident to the end parts M'1, R1, R2 of the ports 21, 23, 24 except the 2nd port 22.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a lateral movement of an optical splitter for distributing optical signals from an optical fiber.

[Technical background of the invention and its problems]

General 1-1 Distributing optical signals to a large number of terminals using passive optical circuit elements is essential for realizing highly reliable optical networks. Conventionally, such passive circuit elements A star coupler is known in which an optical signal input to one input terminal is outputted to all output terminals In, and a star-shaped network centered on this type of coupler is known. However, in such a system, it is necessary to wire optical cables from all stations using star coupler connections, and as the number of stations increases, the overall length of the required optical cable increases, resulting in a cost increase. Also, since many optical cables are connected to one star coupler, the cables become congested and are not necessarily easy to use. For example, even if the total number of stations is large, the number of stations connected to each star coupler 1 is small, and the problems mentioned above can be considered to be eliminated. However, in the conventional star coupler, a part of the optical signal is also distributed to the output terminal of the filter board when the optical signal No. 48 is input, so a closed loop is formed and oscillation occurs.

Normal optical transmission was impossible.

RII, as shown in FIG. If the second star couplers (la) and (1b) output the optical signals supplied to the input terminals (2) of each boat to the output terminals (ζ2) of all boats, then the first star coupler (1a) The optical signal output from the first receiver (2a) passes through the first transmitter (3e,), the second star coupler (1b), and further passes through the second receiver (2b). Through the transmitter (3b), a part of the first star coupler (1aC) is sent out again to the first receiver (2a). In this way, a closed loop is formed and oscillation occurs. In Fig. 1, (4) is an optical transmitter (4a) and an optical receiver (4b).
It is a station consisting of.

The inventor of the present invention previously devised an optical distributor suitable for the above-mentioned system and which does not cause oscillations (4'4J Application No. 57).
-5651). In other words, it is an optical splitter in which an optical signal cannot be output to the output terminal of the boat to which the optical signal is supplied. FIG. 2 shows an example of this type of optical splitter.

This splitter is an example of an optical splitter having three ports, where the first port is an input terminal (lla) and an output terminal (11
b), and the second boat d consists of the input terminal (12a) and the output terminal (12b), and the 43rd boat consists of the input terminal (13a) and the output terminal (13b). 0 optical fiber (two input terminals (lla)
), (12a).

(13a)-2 The input optical signals are transmitted through a convex lens (+
41 causes a predetermined phase shift change in the vertical direction.
Further, after undergoing a horizontal direction C2 phase shift axillary change from the convex lens (15), it enters a deflection matrix plate (16) having six different planes on the radiation # and I sides as shown.

Placed on the output side of this matrix plate (16) 8 tl1
The 4-way matrix plate 67) has an optical effect that is completely opposite to lfi+. Deflection matrix plate (
16) One person enters the upper stage, and the optical signal is divided into two parts, the first half and the second half, and enters the lower and middle parts of the deflection mask plate (17). 1Iil (-& Deflection matrix plate (
10) The optical signals incident on the middle and lower stages are polarized
The optical signal that has passed through the deflection matrix plate (17) is incident on the Jx board (one upper stage, the lower stage, the middle stage, and the upper stage. The optical signal passes through the convex lens ■), the convex lens (ls
), 0.9) and the output terminal (1i
b), (x2b), and (13b).

After all, in this optical splitter, the input terminal of the Ml boat (lla
) is sent to the output terminals (12
b), (13b), but not to the output terminal (llb) of the first boat. Therefore, it is an optical distributor having the above-mentioned characteristics. However, this optical splitter has a complicated configuration and is difficult to adjust, and there are problems in reducing optical loss.

[Purpose of the invention]

The present invention is an improved optical splitter suitable for an optical transmission system having many stations, that is, an improved optical splitter having a characteristic that no optical signal is output to the output terminal of the boat to which the optical signal is supplied. 3. [Summary of the Invention] The present invention provides a transmission surface that transmits an optical signal and a reflection Δ of the optical signal.
A plurality of reflectors with reflective surfaces arranged at a predetermined angle (4i
Then, the optical signal reflected from each input optical fiber end of the plurality of boats consisting of the input optical fiber end and the output optical fiber end is transmitted to the rod lens. Orako) 1. This light No. 414 is reflected from the reflection root group C2 through an optical system equivalent to the above so as to be incident on the output fiber No. 91 of a boat other than the port L at the end of the input fiber from which the light No. 414 was emitted.

〔Effect of the invention〕

According to the present invention, an optical splitter can be installed in an optical transmission system that connects many stations.
fL: A reflection plate jlf', l which has a transmissive surface and a reflection surface such as
91, which is easy to adjust because it obtains the required reflection characteristics.
1 distributor is obtained.

[Embodiments of the invention]

Examples of the present invention will be described below.

FIG. 3 shows the structure of an optical transmission system to which the optical distributor of the present invention is applied. (α1111J bale i?11t, <
A light splitter according to the present invention having, for example, four boats will be described. Each optical distributor has four bows, numbered 1 to 4.

The first section of each optical distributor (a). Second boat (211, (2
21 is connected to the adjacent optical distributor, and the third . A station (2I51) is connected to the fourth boat -1,-.

Each station consists of an optical transmitter (20) that transmits the optical signal No. 48, and an optical receiver body that receives the optical signal.

Each party distributor 1) has characteristics as shown in the schematic diagram of FIG. The board consists of an input optical fiber end for inputting optical signals and an output optical fiber end for outputting optical signals. 1st baud 112tlf'i input optical fiber end (M
l) and the output optical fiber end (M'l), and the second
The boat (η) consists of an input optical fiber (M2) and an output optical fiber (M'2). In addition, the third point (transfer) is connected to the input optical fiber end (TI) and the output optical fiber end (R1).
), and the fourth boat is the input optical fiber end (T
l) and an output optical fiber end (R2).
The optical signal entering each input optical fiber end follows this optical splitter and enters all output optical fiber ends except that boat. For example, an optical signal that enters the input optical fiber end (Mi) of the first boat) is +'N 2 % R3, the fourth
The output optical fiber ends (M'l) of the ports (22i, (111), (R1), (Rg) are distributed together.

This optical distributor has the characteristic that optical signals are distributed in the same manner.

FIG. 5 shows the configuration of an embodiment of the present invention that achieves the above-mentioned characteristics. In Fig. 5 1''-, 11311 ~ 矧 connects its ends to the input optical fiber ends (Ml), (M2),
(TI).

It is an optical fiber with (T's)...) ~ + rj
The output optical fiber ends are (M'l), (M'ri, (Rt), and (J?2)).

FIG. 6 shows the positional relationship between the ends of each input and output optical fiber.

In the figure, the circular portion indicated by a dotted line indicates that an optical fiber having the same size and shape as each party fiber is straddled as a dummy. Above input/output optical fiber 1811
The dummy optical fiber may not be necessary if the correct positional relationship can be maintained only by using the cable. Also, in Fig. 6, the ends (Ml), (MB), (Tl), (T
l), the tip fires toward you, and the end (M'i) +
(Mri)+(Rt) and (Ra) indicate that light is incident on the fiber.

As shown in Figure 5, these input and output lights 77471
Between 7111 and 1, the end faces of Yu1) to m) have a diameter large enough to include all of these end faces, and a cylindrical rod lens ml with a remaining pitch length is attached to one end face. G is split in two so that they touch. At the other end of the rod lens 135), there is a group of reflective plates stacked at a predetermined inclination, each having a reflective surface that reflects the optical signal and a transmitting surface that transmits the optical signal. is provided.

The rod lens (a)) is made so that the refractive index of the outside C1 gradually decreases from its central axis, and the length of one cycle of light bending changes depending on the state of this refractive index. The length of one cycle of the needle is one pitch [7], and here, the length of the rod lens kmf Lr1 - the length of the pitch C is multiplied by two. For example, this rod lens has a diameter of 2 m! 0 reflector group using j% length 5 as (g) li, 44
It consists of 581 light reflecting plates j5t)l~(581).

As shown in Figure 7, the light reflecting plate 1) has its front and back surfaces forming an angle in the y direction (220 angles! has.Here θi1
It is the angle that produces the minimum pitch of the fiber array. Above reflective surface (11 vertically 11
ing. Therefore, due to this repulsion surface, the optical signal emitted from the input optical fiber end (Ml) of ζ1 1211 is transmitted to the output optical fiber end (M' 2) The optical signal emitted from the human power optical fiber end (Mz) of the Ki2 port is flooded by two people.
(M'l) tall's output optical fiber end (M'l) is emitted from two people.

In addition, a light reflecting plate (51
:U As shown in FIG.
(transition) is provided. Reflective surface (six swords are film-like and have a low reflectance of about 1%, which is different from other reflective surfaces.

The back side of the light reflection plate 1511 is connected to the rod lens (the end face of the pair (7 and 2θ, as shown in the 12th image, Optical fiber end (
TI), (Tl), and the emitted light is the 4th and 3rd baud) H, the output optical fiber end of Hll (us), (R
1). Further, the reflection direction with a filling angle of 45° on the front side makes an angle of 2θ-020 in the y direction with respect to the end face of the rod lens mark). In addition, as shown in Fig. 13-2, the reflective surface (by the tooth and the reflective surface, the first,!!,
Input optical fiber end (M] of 2 ports (211, absorption)
)l The optical signal emitted from (M2) is the second. 1st Horde 1. +2.1+ output optical fiber end (R2), (
Rt). Also, the first
As shown in Figure 4, the human-powered optical fiber end (TI) is attached to r), (
Firing from T2) 1. The optical signal is transmitted to the end of the output optical fiber (M
'2)l (M'i) 'Two people shoot.

A reflector plate laminated on the light reflector plate (5I), as shown in FIG. Reflective surface (e))
has. As shown in Figure 15, the input optical fiber end (M2) is connected to the reflective surface (C2) and the reflective surface (M2).

The optical signal emitted from (T2) enters the output optical fiber end (M'2).

On the light reflection plate TFI21 (two fλ layers, the tidal radiation & cape is
As shown in FIG. 10, it has front and back surfaces with an angle of 2θ in the X direction.

This surface has a reflective surface (6 t) as shown in Figure 16 (2) and a reflective surface (7) emitted from the input optical fiber end ('Ml), (TI). The optical signal is output from the output optical fiber end (R1)l (Mi)'
Two people shoot.

Therefore, the optical signals emitted from the input optical fiber ends (M2) of these light reflecting plates 15111 to 15111 (for example, the second boat when the scales are stacked) are as shown in FIGS. 11, 13,
As shown in FIG. 15, the light is incident on the output optical fiber ends (Mi), (R1), and (R1) other than the second boat. In this way, the characteristics shown in FIG. 4 are obtained.

In the above embodiment, an optical signal of a single wavelength is set up by a scattering matrix l2 with n1, so that the luminous flux is divided by 1fn.
Even in the case of multiple wavelengths, it is possible to easily construct an optical circuit element that uses both the wavelength dependence of the reflective film and wavefront division.

According to the above embodiment of the present invention, the wavefront division can be freely set and combined depending on the shape of the reflecting surface of the light reflecting plate.

The two roles can be separated by setting the required deviation of the planes to be laminated (by applying a double force).This increases the degree of freedom of the 11th component and makes it possible to realize optical circuit elements with complex scattering matrices. , a single rod lens provides ijJ function.

Since it can be configured with a single rod lens, it can be made smaller, and it is also possible to reduce incomplete tf4 loss due to rod lens aberrations, fiber array position @ errors, etc. when using multiple rod lenses. In comparison, f2 is easily possible.

It is clear that the optical distributor of the present invention can be applied not only to an optical distributor having four ports as in the above embodiment, but also to an optical distributor having three or five or more ports.

In addition, although the above embodiment uses a rod lens with a daylight pitch length, the present invention is not limited to this, and an equivalent optical system having the characteristics of collimating light and narrowing parallel light can also be used. May be used.

[Brief explanation of the drawing]

Figure 1 is a block diagram of an optical transmission system using a conventional star coupler, Figure KTJ2 is a structural diagram of an optical splitter proposed earlier, and Figure 3 is an optical transmission system using the optical splitter of the present invention. FIG. 4 is a schematic diagram showing 'lfF+ of the optical distributor of the present invention, FIG.
The diagrams show the arrangement of the input and output optical fiber ends of the embodiment of FIG. 5, and FIGS. 7 to 10. The embodiment of FIG. Figures 11 to 16
The figure is a diagram showing the input/output relationship of optical signals in the embodiment of FIG.
...Second boat 23...Third boat 24...Fourth port 25...Station 2 (5...Optical transmitter 27...Optical receiver M1
+ M2+ T1+ T2...Input optical fiber end Wl
iMll Mal R11R2...Output light optical fiber end 35...Rod lens 45...Reflector group 50
~53...Light reflecting plate (7317) Agent Patent attorney Kensuke Chika (and 1 other person) Figure 1 Figure 2 Figure 3 Figure 4 Figure 8 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16

Claims (1)

[Claims] A boat consisting of an input optical fiber end and an output optical fiber end that input and output optical signals, respectively, has a predetermined position:
A port group consisting of two parallel ports, and the light No. 18 emitted from each input fiber end of these boats is sent to the output fiber end of the boat other than the boat at the input fiber end that emitted this optical signal. A plurality of reflector plates each having a transmitting surface that transmits an optical signal and a reflective surface that reflects light (H) as if the light is incident thereon are laminated by holding them at an inclination, and this reflector group and the An optical splitter 0 characterized by comprising a rod lens or an equivalent light-year system interposed between a group of ports and transmitting an optical signal.