US 5,303,079 A · Tunable chirp, lightwave modulator for dispersion compensation

Abstract

External modulation is accomplished in a dual waveguide device wherein substantially identical input optical beams are supplied to the waveguides and wherein each waveguide through its electrode is subject to individual, mutually exclusive control. Modulation signals are applied to each waveguide via its separate electrode. Control signals are applied to each waveguide for adjusting the modulation chirp parameter to a desired fixed, non-zero value. Typically, the desired value of the chirp parameter is one which provides the lowest fiber dispersion penalty for the system. Modulated lightwave signals emerging from the waveguides are combined to form a single output signal suitable for transmission over an optical fiber. In one embodiment, Mach-Zehnder interferometer having separately controllable waveguides has its input coupled to a CW laser. Both III-V semiconductor and Ti:LiNbO.sub.3 Mach-Zehnder interferometers have been utilized as external modulators in accordance with the principles of the present invention.

Claims10

Dependent claims

Apparatus for externally modulating an optical beam with information signal comprising:

first and second waveguide means responsive to the optical beam, each waveguide means including an optical waveguide for supporting propagation of the optical beam and an electrode means for applying signals to the optical waveguide, the electrode means of the first waveguide means being substantially independent from the electrode means of the second waveguide means;
waveguide output means for combining a modulated optical beam from each of said first and second waveguide means into a single modulated optical beam;
and
means responsive to the information for modifying the information to generate first and second modulation control signals, each said modulation control signal including a representation of the information signal, the first and second modulation control signals generated in a predetermined relationship to each other for inducing a predetermined non-zero amount of a modulation chirp parameter in the single modulated optical beam when the first and second modulation control signals are applied to the electrodes of the first and second waveguide means, respectively.

1 more element

Dependencies are inferred from the claim text.

Tunable chirp, lightwave modulator for dispersion compensation

Life of this patent

Tunable chirp, lightwave modulator for dispersion compensation

Life of this patent

Abstract

Claims10