JPH04192579A - Control circuit for laser frequency sweeping - Google Patents

Abstract

PURPOSE:To control the temperature of an electro-optic element and to increase the efficiency of a frequency sweeping operation by providing the following: an electro-optic element through which a laser beam is passed and which is equipped with a heater; and a means to control an electric field inside the electro-optic element. CONSTITUTION:An electro-optic element 2 is provided with a heater 6; its electric input is controlled by a control power supply 7 at the outside in order to control the temperature of the electro-optic element 2 so as to match the characteristic of the electro-optic element 2 whose temperature-dependence is large. Generally, the characteristic of a refractive index for the electro-optic element 2 is temperature-dependent. As a result, the voltage of a power amplifier 3 can be reduced when the element is operated by setting the temperature to be optimum. Thereby, the performance of the electro-optic element 2 is displayed to be maximum, and a frequency sweeping operation can be performed with high efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser frequency sweep control circuit that controls the frequency sweep of laser light.

[Prior Art] FIG. 2 is a block diagram showing a conventional laser frequency sweep control circuit disclosed in, for example, US Pat. No. 4,636,287.

In Figure 2, (1) is a laser beam generation source such as an argon laser, La is the laser beam output from this laser beam generation source (1), and (2) is a laser beam source for sweeping the frequency of this laser beam La. The electro-optical element, Lb is this electro-optical element (2
), the frequency-swept laser output light is output from (
3) a power amplifier electrically connected to the electro-optical element (2) for applying an electric field to the electro-optical element (2);
(4) is an oscillator electrically connected to this power amplifier (3) for giving a control signal to this power amplifier (3);
And (5) is a particle to be irradiated with the laser output light Lb output from the electro-optical element (2).

Note that the power amplifier (3) and the oscillator (4) constitute means for controlling the electric field within the electro-optical element (2).

The conventional laser frequency sweep control circuit is configured as described above, and the laser light La generated by the laser light generation source (1) is input to the electro-optical element (2). At this time, the output of the oscillator (4) ■. The output v8 of the electrical amplifier (3) controlled by The refractive index of the laser beam passing through changes over time.

The amount of change Δn in the refractive index within the electro-optical element (2) is Δn
= K, −(n'/2)・E・・−(1)
It is expressed as Here, Ko is a constant, n is the refractive index, and E is the electric field. When a voltage v8 such that the electric field E changes over time is applied from the power amplifier (3), the frequency sweep amount Δf of the laser beam La becomes Δf=,・d (Δn>
/at 1=K2・dE/dti=Kx・dv−/dtp−(2), where K1, K2, and K are constants, and l is the electro-optical element through which the laser beam La passes. (2) is the distance within.

That is, the electric power EE V given from the power amplifier (3)
w (7) By controlling the amount of change over time, it is possible to obtain laser output light Lb in which the frequency of laser light La is swept.

[Problems to be Solved by the Invention] In conventional laser frequency sweep control circuits, if the characteristics of the electro-optical element have temperature dependence, the temperature of the electro-optical element cannot be controlled, and the frequency sweep efficiency may decrease. , there were problems such as loss of reproducibility when the external environment changed.

This invention was made to solve these problems, and aims to provide a laser frequency sweep control circuit that can control the temperature of an electro-optical element, increase frequency sweep efficiency, and have reproducibility. shall be.

[Means for Solving the Problems] A laser frequency sweep control circuit according to the present invention includes an electro-optical element provided with a heater.

[Function] In this invention, the temperature of the electro-optical element can be controlled in accordance with the characteristics of the electro-optical element, which is highly temperature-dependent, so the performance of the electro-optical element can be maximized, and efficient frequency sweeping can be achieved. be done.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the laser frequency sweep control circuit according to the present invention. In the figure, (6) is a heater provided in the electro-optical element (2), and its electrical input is external. is controlled by a control power source (7). In general, the refractive index of the electro-optical element (2) has temperature dependence, so if the temperature is set optimally and the electro-optical element (2) is operated,
The voltage of the power amplifier (5) can also be reduced.

[Effects of the Invention] In this invention, since the electro-optical element is provided with a heater, the temperature of the electro-optical element can be set according to the temperature characteristics of the electro-optical element, so that the performance of the electro-optical element can be maximized. This has the effect of realizing efficient frequency sweep.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional laser frequency sweep control circuit. In the figure, (2) is an electro-optical element, (3) is a power amplifier, (4) is an oscillator, and (6) is a heater. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A laser frequency sweep control circuit comprising: an electro-optical element through which laser light passes and is provided with a heater; and means for controlling an electric field within the electro-optical element.