JPS62284328A - Optical tuner - Google Patents

Abstract

PURPOSE:To constitute an optical tuner by a simple structure, and to manufacture new optical parts being suitable for an optical wavelength multiplex transmission of a broadcasting type, by providing a rotary mechanism on a plane linear diffraction grating, and also, providing one piece of photodetector. CONSTITUTION:Five different signals from an input optical fiber 3 are superposed on a light beam consisting of five different wavelengths, and its light beam is made incident on a plane linear diffraction grating 1 through a lens 2. As a result, the light beam consisting of five different wavelengths is subjected to a wavelength dispersion and reflected at a different angle at every wavelength, and also, condensed by the lens 2, only one wavelength in the light beam whose wavelengths are different from each other forms a focus on the end face of a photodetector 4, and the light of other wavelength is not made incident on the photodetector 4. Accordingly, at the time of photodetecting the light beam of other wavelength, the plane linear diffraction grating is brought to a rotational operation by using a rotary mechanism 5, and the light beam of a necessary wavelength is made incident on the photodetector 4. In such a way, an optical tuber can be constituted by a simple structure.

Description

Detailed Description of the Invention 3. 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 tuner communication.

Conventional technology In recent years, optical wavelength division multiplexing transmission technology has been used as a means of effectively utilizing a single optical fiber in optical fiber transmission to increase transmission capacity by transmitting multiple signals at different wavelengths. There is.

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, 34.3'5.36°37.38 is an output optical fiber, and 39.40.41°42.43 is an optical fiber. An electrical transducer is shown in which the lens 42 is placed between the planar linear diffraction grating 41 and the input optical fiber 43 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 are converged by the lens, and the lights with different wavelengths are sent to output optical fibers 34, 3.
5, 36. The light is received at 37° 38 and the light-to-electrical converter 39.
40, 41° and 42.43 degrees, respectively, and are converted into electrical signals.

(For example, r1978 IEICE Technical Research Report,
C3TB-166, pages 37 to 42) Problems to be Solved by the Invention However, although the above configuration is suitable for receiving multiple wideband signals at once, it is not suitable for receiving multiple channels of television signals. When only one signal, or one wavelength, is required at a time, such as broadcast-type optical wavelength division multiplexing, in which signals are transmitted over a single optical fiber, the optical fiber and optical-to-electrical converter are used as a set. However, due to the high cost of optical-to-electrical converters, parts with new functions were desired.

The present invention takes the above-mentioned problems into consideration and provides an optical tuner that 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 includes a wavelength selection element, and a wavelength selection element that inputs light into the wavelength selection element and receives light from the wavelength selection element. , has one input optical fiber and one light receiving element arranged in a space in front of the wavelength selection element, and inputs a plurality of wavelengths from the one input optical fiber to the wavelength selection element and receives the light. The device is equipped with a mechanism for operating the wavelength selection element so as to manually apply light of a required wavelength to the element.

Effects The present invention has the above-described configuration, and by providing a mechanism for operating the wavelength selection element, it is possible to convert only the light of the required wavelength from among the light of a plurality of wavelengths into electricity using one light receiving element. , it is possible to create an optical tuner with a simple structure.

EXAMPLE Hereinafter, an optical tuner according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows an optical tuner in an embodiment of the present invention. In FIG. 1, 1 indicates a plane linear diffraction grating as a wavelength selection element, and 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 entering the planar linear diffraction grating 1 through the lens 2, the light consisting of the five different wavelengths undergoes wavelength dispersion and is reflected at a different angle for each wavelength, and is condensed by the lens 2. Only the light of one wavelength among the lights of different wavelengths is focused on the end face of the light receiving element 4, and the light of other wavelengths is not incident on the light receiving element 4.

Therefore, when receiving light of other wavelengths, the rotating mechanism 5
The planar linear diffraction grating may be rotated by using the above-mentioned method, and light of a desired wavelength may be incident on the light-receiving element.

Figure 2 shows the output characteristics of light input to the light receiving element when the planar linear diffraction grating is rotated. λ2゜λ3. λ4. Light of five wavelengths of λ5 is input sequentially, and signals carried at each wavelength can be extracted.

As described above, according to this embodiment, by attaching a rotation mechanism to a planar linear diffraction grating, optical wavelength multiplexing transmission can be achieved, similar to a conventional optical demultiplexer with a wavelength selection effect using a single light receiving element. It is intended to provide parts with new functionality.

Further, 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.

In this embodiment, a case has been described in which a diffraction grating is used, but similar effects can be obtained by using a mechanism that combines or rotates interference film filters, or a mechanism that rotates a prism.

Effects of the Invention As described above, the present invention provides a rotating mechanism for a flat linear diffraction grating and also provides one light receiving element.
An optical tuner can be constructed from an optical member having a very simple shape, and a new optical component suitable for broadcast-type optical wavelength division multiplexing transmission can be created.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an optical tuner in an embodiment of the present invention;
FIG. 2 is a characteristic diagram showing wavelength selection characteristics of a plane diffraction grating, and FIG. 3 is a perspective view of a conventional optical demultiplexer. 1...Planar linear diffraction grating, 2...Lens, 3...Input optical fiber, 4...Photodetector, 5...Rotation mechanism. Name of agent Patent attorney Toshio Nakao Haka 1 Naa 2 Illustrated f to 2-to 3 → enter 4-person 5 Watari Moxibustion

Claims (1)

[Claims] A wavelength selection element and one input optical fiber and one light receiving element arranged in a space in front of the wavelength selection element so as to input light into the wavelength selection element and receive light from the wavelength selection element. inputting a plurality of wavelengths from the single input optical fiber to the wavelength selection element,
An optical tuner comprising a mechanism for operating the wavelength selection element so as to input light of a desired wavelength to the light receiving element.