JPH0143286B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical switch that distributes light propagating through an optical fiber to another optical fiber.

The applicant proposed an optical switch in Japanese Patent Application No. 53-28150. This is shown in Figure 1,
End face 2 of a self-focusing lens 1 with a period length of approximately 1/4 (light rays propagating within a focusing lens meander in a sinusoidal manner at a constant period. This meandering period is called the period length of the focusing lens). 7 optical fibers 3,
4 and 5 are glued together and the light emitted from the central fiber 3 is made into a parallel beam.Then, the direction of reflection is controlled by the movable mirror 6, an arbitrary fiber is selected from among the optical fibers 4 and 5, and the light is made into a parallel beam. The light is incident on that fabric.

Next, FIG. 2 shows an example in which this optical switch is used in an optical exchange. 11 to 14 are optical switches, 15 is an optical exchanger constituted by a group of these switches, and 16 to 19
is a user terminal. When using such an exchange, for example, when user 16 wishes to communicate with user 18, user 16 must send a tuning command signal to the optical exchange to set the optical switch to the 18 side. Therefore, when using the above-mentioned optical switch, it is necessary to provide a transmission line for transmitting such a channel selection signal separately from the optical transmission line for communication.

The present invention transmits a communication signal and a channel selection signal in a multiplex manner using only an optical transmission line for communication, without providing a special signal transmission line for channel selection, and monitors the multiplexed signal. The purpose of this invention is to provide an optical switch that selects a specific transmission line by switching the switch.

FIGS. 3a and 3b are a front view and a side view showing an embodiment of the present invention. In the figure, 20 is a self-focusing lens, 21 is an end face thereof, 22 is a reflecting mirror configured so that the angle of inclination can be arbitrarily changed by a driving means (not shown) such as a motor, and 23 to
29 is an optical fiber. The focal point of the lens 20 is 1
00, and the end surfaces of the optical fibers 23 to 29 are arranged on a plane 101 that includes a focal point 100. In this embodiment, the period of the self-focusing lens is 1/4 pitch, so the focal point is on the end surface of the lens, but if the lens is slightly shorter than 1/4, the focal point will be outside the lens end surface. In this case, it is necessary to insert a spacer or the like between the lens and the fiber.

The fibers 23 and 25 are arranged in a symmetrical relationship with respect to the optical axis 102 of the lens 20, respectively. After the light incident from focal plane X is reflected by the end face of the focusing lens, the light returns to focal plane Y.
to focus. At this time, the perpendicular line drawn from the midpoint between X and Y to the end surface of the lens is called the optical axis.

In such a device, the light emitted from the fiber 23 becomes a collimated beam within the self-focusing lens 20, is partially reflected at the end face 21 of the lens, and is focused on the end face of the fiber 25. On the other hand, the light transmitted through the end surface 21 is reflected by the reflecting mirror 22, and after passing through the self-focusing lens 20, it converges at a specific position on the lens end surface according to the inclination of the reflecting mirror, and the light corresponds to that position.
The signal is transmitted through one of the fibers 24, 26, 27, 28, and 29.

With the above configuration, the light partially reflected by the end face 21 of the lens reliably converges on the end face of the fiber 25 without being affected by the inclination of the reflecting mirror. It's fine. As is clear, when the end surface 21 of the lens is an optical filter,
Light of a specific wavelength can be used as a channel selection signal. That is, a multiplexed signal consisting of a communication signal and a channel selection signal is transmitted through the fiber 23, and the multiplexed signal partially reflected by the end face 21 of the lens is transmitted through the fiber 25.
A light receiving element (not shown) receives the light through the channel, and detects the channel selection signal in the multiplexed signal. Drives a driving means such as a motor according to the command of the detected channel selection signal, changes the angle of the reflecting mirror 22 in an arbitrary direction,
This is to control the reflected light so that it selectively passes through a specific transmission path. Here, the influence of reflected light between fibers will be considered. For example, fiber 27 is selected as the transmission path, and fiber 27 is selected as the transmission path.
When the light output to 7 is reflected by an optical connector or the like, the reflected light enters the self-focusing lens 20 from the fiber 27 again. Of this reflected light, the light reflected by the lens end face 21 enters the fiber 29. By the way, since the reflectance at the end face of the lens and the end face of the optical connector is about 4%, the ratio of the light incident on the fiber 23 outputting to the fiber 29 is about 0.16% (crosstalk about 28 dB), which is not a problem in practice. it is obvious.

As described above, the optical switch of the present invention has two optical fibers arranged at symmetrical positions with respect to the optical axis of the optical lens, and a part of the optical signal sent from one optical fiber is This method attempts to distribute the optical signal to the selected optical fiber by reflecting it off the end face of the lens, extracting this reflected light with another optical fiber, and controlling the displacement of the reflector based on the extracted reflected light. Yes, (1) there is no need to provide a separate optical transmission line for switching optical switches, (2) all signals can be processed as optical signals and are not affected by electromagnetic noise, (3) the structure has a small number of components. (4) The symmetrical arrangement of the two optical fibers with respect to the lens is easy to construct, and in normal cases, there is no need to form a special reflective film.

[Brief explanation of drawings]

Figure 1 is a configuration diagram showing a conventional optical switch;
The figure is a configuration diagram showing an optical exchanger, and FIGS. 3a and 3b are a front view, a side view, and a configuration diagram showing an embodiment of the present invention. 20, 31-31′′′′... Self-focusing lens,
22, 32...Reflector, 23-29, 30-30
′′′′；34...Optical fiber.

Claims (1)

[Claims] 1. Arranging the end faces of the two first group optical fibers at symmetrical positions with respect to the optical axis of the optical lens on a plane including the focal point on the light incident surface side of the optical lens, and A plurality of optical fibers of a second group are arranged around the first optical fiber as the input optical fiber so that the distance between the axes with the input optical fiber is equal, and the optical fibers of the second group are arranged opposite to the light entrance surface of the optical lens. A reflector whose reflection direction is variable is installed on a side surface to reflect the light that has passed through the optical lens from one of the incident optical fibers of the first group;
The direction of reflection of the reflector is changed based on the reflected light signal at the end face of the optical lens from one of the incident optical fibers of the first group, which is detected by the other optical fibers of the group, and An optical switch characterized in that the light is selectively outputted to any one optical fiber of the second group.