Abstract: A system and method for stabilizing a plurality of output frequencies (wavelengths) of a plurality of lasers (106). The laser beams are combined using optical multiplexer (110) and coupled into length-imbalanced (armlength-mismatched) Mach-Zehnder interferometer (MZI) (114) having an optical modulator (e.g. AOM) (122) in one of its arms. The output of the MZI is divided into corresponding beams via optical demultiplexer (128) and each beam is detected by a respective photo-diode (PD) (134). The individual electric signals, so generated, are demodulated using a corresponding plurality of phase-responsive devices (138) and the resulting phase-signals are directed to a plurality of servo-controllers (148) to control the central frequency of the respective lasers (106) via a corresponding plurality of feedback loop circuits (150). The lasers (106) can have different central frequencies which can also be individually tunned using offset modules (141) in the phase-responsive devices (138).

Abstract: A system and method for stabilising a plurality of output frequencies (wavelengths) of a plurality of lasers (106). The laser beams are combined using optical multiplexer (110) and coupled into length-imbalanced (armlength-mismatched) Mach-Zehnder interferometer (MZI) (114) having an optical modulator (e.g. AOM) (122) in one of its arms. The output of the MZI is divided into corresponding beams via optical demultiplexer (128) and each beam is detected by a respective photo-diode (PD) (134). The individual electric signals, so generated, are demodulated using a corresponding plurality of phase-responsive devices (138) and the resulting phase-signals are directed to a plurality of servo-controllers (148) to control the central frequency of the respective lasers (106) via a corresponding plurality of feedback loop circuits (150). The lasers (106) can have different central frequencies which can also be individually tunned using offset modules (141) in the phase-responsive devices (138).

Abstract: An apparatus for interferometric sensing, comprising a plurality of single-longitudinal mode laser sources to each provide radiation at a corresponding plurality of selected wavelengths, and at least one modulator to frequency or phase modulate the radiation from each laser; a plurality of Fabry-Perot interferometers formed by Bragg Gratings written into optical fibre, each interferometer being responsive to one of the said plurality of wavelengths to each produce a reflected or transmitted optical output signal dependent on the corresponding interferometer path length; and one or more demodulators to demodulate the optical output signals and produce a corresponding plurality of measurement signals indicative of optical path lengths of the respective interferometers.

Abstract: An apparatus for interferometric sensing, comprising a plurality of single-longitudinal mode laser sources to each provide radiation at a corresponding plurality of selected wavelengths, and at least one modulator to frequency or phase modulate the radiation from each laser; a plurality of Fabry-Perot interferometers formed by Bragg Gratings written into optical fibre, each interferometer being responsive to one of the said plurality of wavelengths to each produce a reflected or transmitted optical output signal dependent on the corresponding interferometer path length; and one or more demodulators to demodulate the optical output signals and produce a corresponding plurality of measurement signals indicative of optical path lengths of the respective interferometers.