JPH01128006A - Optical tuner - Google Patents

Abstract

PURPOSE:To provide an optical tuner having a simple structure capable of receiving only the light of a necessary wavelength from plural wavelengths in a piece of an output optical fiber by providing a rotating mechanism consisting of a piezo-electric actuator element to a holographic diffraction grating. CONSTITUTION:Five different signals from the input optical fiber 3 are entrained in the light consisting of five different wavelengths and is projected diagonally to the holographic diffraction grating 1 through a lens 2, by which the light consisting of the five different wavelengths is subjected to wavelength dispersion and is reflected at the angle varying with each wavelength. This is condensed by the lens 2 and only the light of one wavelength N in the light of the different wavelengths is focused onto the end face of the output optical fiber 4. The light of the other wavelengths is not projected onto the output optical fiber. The light of the other wavelengths can, therefore, be received simply by applying a voltage to the piezo-electric actuator element 5 mounted to a support 7 to displace the piezo-electric actuator element and to rotate the holographic diffraction grating around a fulcrum point 6 so as to project the light of the required wavelength on the output optical fiber 4.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical tuner used on the receiving side of optical wavelength division multiplexing transmission in optical fiber communications.

Conventional technology In recent years, optical wavelength division multiplexing transmission technology has become a means of increasing signal transmission capacity by effectively utilizing a single optical fiber to transmit multiple signals on different wavelengths. It is attracting attention and being used as such.

Conventionally, in the above-mentioned optical wavelength division multiplexing transmission, on the receiving side,
Optical demultiplexers were used to split light into wavelengths.

An example of this optical demultiplexer will be described below with reference to the drawings.

FIG. 3 shows a conventional optical demultiplexer. In Fig. 3, 31 is a planar linear diffraction grating, 32 is a lens, 33 is an input optical fiber, 34.35° 36.37.38 is an output optical fiber, and 39.40° 41.42.43 is an optical-to-electrical converter. The lens 32 is arranged between the planar linear diffraction grating 31 and the input optical fiber 33 and the output optical fiber 34.35, 36.37.38.

The operation of the optical demultiplexer configured as described above will be explained below.

By inputting light consisting of five different wavelengths from the input optical fiber 33 to the plane linear diffraction grating through the lens 32, the light undergoes wavelength dispersion and is reflected at different angles for each wavelength. The lights converged by the lens and having different wavelengths are outputted to output optical fibers 34 and 35.
．． The light is received at 36,37°38, and the light-to-electrical converter 39.4
0.41°42.4'3 are converted into electrical signals, respectively.

(For example, 1978 IEICE Technical Research Report, C378-166, pages 37 to 42) Problems to be Solved by the Invention However, with the above configuration, multiple broadband signals are received at the same time. However, it is suitable for cases where only one signal, or one wavelength, is required at a time, such as broadcast-type optical wavelength division multiplexing, which transmits many channels of television signals over a single optical fiber. For this, only one set of optical fiber and optical-to-electrical converter is required, and since the cost of the optical-to-electrical converter is high, parts with new functions have been desired.

The present invention takes the above-mentioned problems into consideration and provides a photon energizer which is an optical receiving side device most suitable for broadcast-type optical wavelength division multiplexing transmission.

Means for Solving the Problems In order to solve the above problems, the optical tuner of the present invention has one input optical fiber, one output optical fiber, and a space in front of the input optical fiber and the output optical fiber. and a holographic diffraction grating arranged obliquely with respect to the optical axes of the input optical fiber and the output optical fiber in a space in front of the lens, and the holographic diffraction grating includes a piezoelectric actuator element. It is equipped with a rotation mechanism using.

Effect of the present invention With the above-described configuration, by providing a rotation mechanism to the holographic diffraction grating, it is possible to receive only light of a required wavelength from among a plurality of wavelengths with a single output optical fiber. A light chainer with a simple structure can be created.

Embodiment Hereinafter, an optical chainer according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an optical chainer according to the present invention.

In FIG. 1, l indicates a holographic diffraction grating,
2 indicates a lens.

In the above-mentioned configuration, five different signals from the input optical fiber 3 are put on light consisting of five different wavelengths,
By obliquely entering the holographic diffraction grating l through the lens 2, the light consisting of the five different wavelengths undergoes wavelength dispersion and is reflected at different angles for each wavelength, and is condensed by the lens 2. , among the lights of different wavelengths, only one light of wavelength N is focused on the end face of the output optical fiber 4, and light of other wavelengths is not input to the output optical fiber.

Therefore, when receiving light of another wavelength, by applying a voltage to the piezoelectric actuator element 5 attached to the support 7, the piezoelectric actuator element is displaced as shown in FIG. The holographic diffraction grating may be rotated around 6 to input light of a desired wavelength into the output optical fiber 4. 8 represents an optical-to-electrical converter, which converts the light input into the output optical fiber 4. Convert to electrical signal.

In particular, at the so-called Littrow angle where the first-order diffracted light returns onto the incident optical axis, the input optical fiber and the output optical fiber can be placed in contact, which is advantageous in terms of miniaturization.

FIG. 2 is a diagram showing the voltage and displacement amount of the piezoelectric actuator element.

When a laminated piezoelectric actuator element is used, the piezoelectric actuator element has a characteristic that the torque is large and the amount of potential changes linearly with respect to the voltage. In addition, the amount of displacement caused by the charge further increases linearity.

On the other hand, when a bimorph type piezoelectric actuator element is used as the piezoelectric actuator element, it has the advantage that a large amount of variation can be obtained with a low voltage.

Additionally, holographic diffraction gratings are easier to create than conventional mechanically scored diffraction gratings.

As described above, according to this embodiment, by attaching a rotation mechanism using a piezoelectric actuator element to a holographic diffraction grating, a conventional optical demultiplexer can have a wavelength selection effect. The input optical fiber and the output optical fiber can be brought closer to each other, and the present invention provides a component with new functions for compact, high-performance optical wavelength division multiplexing transmission.

In this embodiment, a reflection type diffraction grating has been described, but similar effects can be obtained with a transmission type diffraction grating or one including a mirror system.

Effects of the Invention As described above, the present invention provides a holographic diffraction grating with a rotation mechanism using a piezoelectric actuator element, thereby making it possible to configure an optical tuner with an optical member having a very simple shape. New optical components suitable for multiplex transmission can be created.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an optical tuner in an embodiment of the present invention;
FIG. 2 is a graph showing the relationship between voltage and displacement of a piezoelectric actuator element, and FIG. 3 is a perspective view of a conventional optical demultiplexer. 1... Holographic diffraction grating, 2...
...Lens, 3...Input optical fiber, 4...
... Output optical fiber, 5 ... Piezoelectric actuator element, 6 ... Fulcrum, 7 ... Support body, 8 ... Optical-electrical converter. Name of agent: Patent attorney Toshio Nakao /---j
rX1: J quay 5 Hff −ri

Claims (3)

[Claims] (1) One input optical fiber, one output optical fiber, a lens disposed in a space in front of the input optical fiber and the output optical fiber, and a lens disposed in the space in front of the lens, the input optical fiber and the output optical fiber An optical tuner comprising: a holographic diffraction grating disposed obliquely to the optical axis of an optical fiber, the holographic diffraction grating comprising a rotation mechanism using a piezoelectric actuator element. (2) Claim No. (2) characterized in that a laminated piezoelectric actuator element is used as the piezoelectric actuator element.
The optical tuner described in section 1). (3) The optical tuner according to claim (1), characterized in that a bimorph piezoelectric actuator element is used as the piezoelectric actuator element.