JPH01180516A - Optical modulator - Google Patents

Abstract

PURPOSE:To vary the light quantity at a high speed by providing an analog A/O modulator for modulating a stabilized laser by an analog A/O control signal and generating optical modulation signal. CONSTITUTION:A laser light source 1 generates laser light (a). A laser light quantity control part 2 controls the laser light (a) by a light quantity command signal b-1, and generates stabilized laser light (c) from which the noise has been eliminated. A level switching circuit 3-1 generates an analog A/O control signal d-2 which has brought amplitude of a digital modulation signal d-1 to amplitude modulation by a level switching signal (e). An analog A/O modulator 4-1 modulates the stabilized laser light (c) by an analog A/O control signal d-2, and generates an optical modulation signal (f). In such a way, an analog type is used, and this modulator is allowed to have both a switching function for turning ON/OFF an optical signal, and a function for making a level in an ON state variable, by which the light quantity can be varied at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical modulator, and particularly to an optical modulator that can vary the amount of laser light.

[Conventional technology]

A conventional optical modulator includes a level switching circuit, a laser light amount control section, and a digital A/O modulator.

Next, a conventional optical modulator will be described in detail with reference to the drawings.

FIG. 2 is a block diagram showing an example of a conventional optical modulator.

The optical modulator shown in FIG. 2 includes a laser light source 1, a level switching circuit 3-2, and a laser light amount control section 2.

It includes a digital A/O modulator 4-2.

Here, the laser light source 1 generates laser light a.

The level switching circuit 3-2 generates a light amount setting signal b-2 by modulating the amplitude of the light amount command signal b-s with the level switching signal e.

The laser light amount control unit 2 controls the laser light a using the light amount setting signal e, and generates a stabilized laser light C from which noise has been removed. The light intensity of this stabilized laser [c is synchronized with the level switching signal e. The digital A/O modulator 4-2 stabilizes the source C and converts it into a digitally modulated signal d-
1 to generate an optical modulation signal f.

[Problem that the invention seeks to solve]

The above-mentioned conventional optical modulator has a drawback that the speed of changing the light amount is slow because the portion that changes the light amount is performed by a laser light amount controller that removes noise.

[Means for solving problems]

The optical modulator of the present invention includes a laser light amount control section that controls a laser source using a light amount command signal to generate a stabilized laser beam, and an analog A/O control signal that modulates the amplitude of a digital modulation signal using a level switching signal. an analog A/O that modulates the stabilized laser source with the analog A/O control signal and generates an optical modulation signal;
and a modulator.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

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

The optical modulator shown in FIG. 1 includes a laser light source 1, a laser light amount control section 2, a level switching circuit 3-1, and an analog A/O
The modulator 4-+ is configured to include a modulator 4-+.

Here, a laser ft and a source l generate a laser source a.

The laser light amount control unit 2 controls the amount of the laser source a according to the light amount command signal b-1, and generates stabilized lasers yt and c from which noise has been removed.

The level switching circuit 3-t converts the amplitude of the digital modulation signal dr into an analog signal A by amplitude modulating the level switching signal e.
/O generates control signal d-2.

The analog A/O modulator 4-t modulates the stabilized laser beam C using the analog A/O control signal dz to generate an optical modulation signal f.

〔Effect of the invention〕

The optical modulator of the present invention uses an analog type instead of a digital type for the A/O modulator, and has both the function of switching the original signal on/off and the function of making the level variable with the on-state M. This has the effect of increasing the speed at which the amount of light changes.

[Brief explanation of the drawing]

Section 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of the prior art. 1... Laser light source, 2... Laser light amount control section, 3-
1.3-1... Level switching circuit, 4-1... Analog A/O modulator, 4-2... Digital A/O modulator, a... Laser source, b-! ...Light amount command signal, b-
z-...Light amount setting signal, C...Stabilized laser beam, d-
1...Digital modulation signal, d-2...Analog A
/O control signal, e: level switching signal, f: optical modulation signal. Agent: Patent Attorney Shinyoshi Uchihara 1 Zu Atsushi 2 times

Claims (1)

[Claims] A laser light amount control unit that controls the laser light using a light amount command signal and generates a stabilized laser light, and an analog A/O that modulates the amplitude of the digital modulation signal using a level switching signal.
An optical modulator comprising: a level switching circuit that generates a control signal; and an analog A/O modulator that modulates the stabilized laser beam with the analog A/O control signal and generates an optical modulation signal. .