US 7,068,950 B2 · Correcting misalignment between data and a carrier signal in transmitters

Abstract

A device and technique for aligning an optical carrier signal (e.g., a soliton pulse train) with a data signal in a transmitter. According to the invention, the device is configured to analyze the radio frequency (RF) spectrum of the transmitter's output. In one implementation, the device evaluates the amount of energy in a certain frequency band located near a selected null of the RF spectrum. In another implementation, the device examines the shape of the RF spectrum within that frequency band. In either case, based on the analysis, the device adjusts the phase of the clock signal driving an electro-optic (E/O) modulator in the transmitter. Such adjustment reduces misalignment between the optical carrier signal and data resulting, e.g., from thermal effects in the E/O modulator. The device may be used, e.g., in long-haul optical transmission systems operating at 10 GBit/s.

Claims36

Dependent claims

An apparatus for reducing misalignment between a carrier signal and a data signal, the apparatus comprising:

(a) an analyzer configured (i) to analyze spectral power of an input signal corresponding to the carrier and data signals, the spectral power being in a spectral band corresponding to a spectral null of the input signal, and (ii) to generate a control signal based on the analysis;
and
(b) a phase shifter configured to introduce a phase shift between the data signal and a clock signal using the control signal, wherein the carrier signal is based on the clock signal.

Dependencies are inferred from the claim text.

Correcting misalignment between data and a carrier signal in transmitters

Life of this patent

Correcting misalignment between data and a carrier signal in transmitters

Life of this patent

Abstract

Claims36