JPH07333255A - Signal converter - Google Patents

Abstract

PURPOSE:To provide a signal converter capable of taking a wide dynamic range. CONSTITUTION:A signal converter apparatus comprises a laser device 1 that emits a laser light, an optical probe 2 that receives the laser light from the laser device 1 and an input electric signal (I) and varies the intensity of a penetration light corresponding to the intensity of the input electric signal (I), a light-dividing device 3 that divides the output light from the optical probe 2 and a photoelectric transducer 4 that converts one of the divided output light of the light-dividing device 3 to an electric signal. It further comprises a correction device 5 that receives the output signal from the photoelectric transducer 4 and input electric signal to obtain a difference between them, i.e. a correction signal and applies the correction signal to the optical probe 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal converter for converting an electric signal into an optical signal.

[0002]

2. Description of the Related Art A conventional signal converter, as shown in FIG. 3, receives a laser 1 for emitting a laser beam, a laser beam from the laser 1 and an input electrical signal from an antenna or the like, and receives the input electrical signal. And an optical probe 2 whose transmitted light intensity changes according to the intensity. The relationship between the characteristic curve of the optical probe 2, the input electric signal, and the transmitted light intensity in the conventional signal converter is shown in FIG. 4, for example.

[0003]

However, in the conventional signal converter, since the linear portion of the characteristic curve of the optical probe 2 is not large, the transmitted light has distortion with respect to the input electric signal, There is a problem that the dynamic range cannot be wide.

An object of the present invention is to provide a signal conversion device which can have a wide dynamic range.

[0005]

In order to solve the above-mentioned problems, the present invention provides a laser for emitting a laser beam, a laser beam from the laser and an input electric signal, and the intensity of the input electric signal. An optical probe whose intensity of transmitted light changes according to the photoelectric conversion device, which converts the output light from the optical probe into an electric signal, receives an output signal from the photoelectric conversion device and the input electric signal, and outputs a difference between them. And a correction device for giving the correction signal to the optical probe.

[0006]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. As shown in FIG. 1, the signal conversion device of the present invention receives a laser 1 that emits a laser beam, a laser beam from the laser 1 and an input electrical signal I, and transmits the laser beam according to the intensity of the input electrical signal I. Optical probe 2 with variable light intensity
An optical branching device 3 for branching the output light from the optical probe 2, a photoelectric conversion device 4 for converting one output light of the optical branching device 3 into an electric signal, and an output signal from the photoelectric conversion device 4. And the input electric signal, a correction signal which is the difference between them is obtained, and the correction signal is obtained.
And a correction device 5 for giving The correction device 5 is
An amplifier 6 for amplifying an output signal from the photoelectric conversion device 4,
The comparator 7 receives the output signal from the amplifier 6 and the input electric signal I and compares them, and the output signal of the comparator 7 is amplified to generate the correction signal and apply it to the optical probe 2. And an amplifier 8.

The laser 1 is composed of, for example, a semiconductor laser. The laser 1 and the optical probe 2 are connected by an optical fiber 9. The optical probe 2 and the optical branching device 3 are connected by an optical fiber 10. Optical branching device 3
The photoelectric conversion device 4 and the photoelectric conversion device 4 are connected by an optical fiber 11. The other output light of the optical branching device 3 is guided by the optical fiber 12. The photoelectric conversion device 4, the amplifier 6, the comparator 7, and the amplifier 8 are connected by conducting wires 13, 14, and 15, respectively. The amplifier 8 and the optical probe 2 are connected by a conductor 16.

The optical probe 2, as shown in FIG.
A substrate 17, an incident optical waveguide 18 formed on the substrate 17 so as to receive incident light from the optical fiber 9, and a substrate 17 formed so as to branch from the incident optical waveguide 18 and refracted by an electric field strength. Two phase shift waveguides 19 of which the rate changes and an emission optical waveguide 2 formed on the substrate 17 so that these phase shift waveguides 19 are coupled to each other.
0 and 2 provided near the phase shift waveguide 19
It consists of two electrodes 21. When different electric fields are applied to the two electrodes 21 by the input electric signal I from the antenna or the like, the refractive index of the phase shift waveguide 19 changes,
A phase difference occurs in the transmitted light propagating through the two phase shift waveguides 19. Therefore, the input electric signal I is converted into an optical signal by the optical probe 2. At the time of this conversion, the correction device 5
Gives a correction signal to the optical probe 2, so that an optical signal is generated corresponding to the input electric signal.

[0010]

According to the present invention, since the correction signal is given to the optical probe, the dynamic range can be widened.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a schematic view showing an optical probe according to one embodiment of the present invention.

FIG. 3 is a block diagram showing a conventional signal conversion device.

FIG. 4 is a diagram showing characteristics of an optical probe in a conventional signal conversion device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser 2 Optical probe 3 Optical branching device 4 Photoelectric conversion device 5 Correction device 6,8 Amplifier 7 Comparator 9-12 Optical fiber 13-16 Conducting wire 17 Substrate 18 Incident optical waveguide 19 Phase shift waveguide 20 Emitting optical waveguide 21 Electrode

Claims (1)

[Claims] 1. A laser that emits a laser beam, an optical probe that receives the laser beam from the laser and an input electric signal, and changes the intensity of transmitted light according to the intensity of the input electric signal, and the optical probe. An optical branching device for branching the output light of the optical branching device, a photoelectric conversion device for converting one output light of the optical branching device into an electric signal, a difference between the output signal from the photoelectric conversion device and the input electric signal. And a correction device for providing the correction signal to the optical probe.