1,720,976 research outputs found
Amplified fiber ring resonator gyro
No full textThe sensitivity of a fiber-optic ring resonator gyro increases with increasing resonator finesse, which can be achieved by including a fiber amplifier in the ring. The spontaneous emission from a fiber amplifier introduces additional noise. The effect of this noise on the performance of an ARRG is theoretically investigated, assuming an infinity source coherence length. It is found that for a given fiber length, the uncertainty in measuring the rotation rate with an ARRG can be more than one order of magnitude lower than with a shot noise limited PRRG, and about three orders of magnitude lower than with an IFOG
Noise in amplified fibre optic recirculating-ring delay lines
No full textWe characterize for the first time the noise in fiber optic recirculating-ring delay lines including doped fiber amplifiers, which are interesting components in many fiber optic sensors because of their enhanced total delay times compared to conventional recirculating-ring delay lines
Noise analysis of an amplified fiber-optic recirculating-ring delay line
No full textWe present the first theoretical and experimental noise analysis of a fiber-optic recirculating-ring delay line (RDL) including a doped fiber amplifier to compensate for the roundtrip loss. Both thermal-like sources and laser sources are considered. The output source induced noise (signal-signal beat noise), signal-spontaneous (s-sp) beat noise, and spontaneous-spontaneous (sp-sp) beat noise spectra for a thermal-like source are calculated from the autocorrelation function of the output detector current. It is shown that all three electrical beat noise spectra can be expressed as correlations of the output optical signal and ASE spectra. The source-induced noise will normally be the dominating noise source, but in some applications, the other noise terms also will be of importance. We use our theory to define the maximum number of recirculations in an amplified RDL with a pulsed source, where the fundamental noise floor is determined by the sp-sp beat noise
Single-frequency Er<sup>3+</sup>-doped fibre lasers
No full textSingle frequency Er3+-doped fibre lasers are emerging as interesting alternatives to distributed feedback (DFB) diode lasers for use in future high-capacity 1.5µm WDM communication systems, as well as CATV, LIDAR, fibre-optic sensor and spectroscopy applications. In general, fibre lasers are fibre-compatible, scalable to high output powers and have low intensity noise and kHz linewidths. Most work on single-frequency fibre lasers has been concentrated on: 1) long travelling-wave fibre ring-lasers, where single-mode operation is obtained by eliminating spatial hole-burning (the factor which causes multi-mode operation in fibre lasers), and 2) short linear-cavity distributed Bragg reflector (DBR) fibre lasers employing fibre grating Bragg reflectors for feedback and mode suppression. Recently also a fibre distributed feedback (DFB) laser, where the feedback is provided by one single fibre grating occupying the entire cavity length and a single-frequency fibre Fabry-Perot micro laser have been demonstrated
Polarimetric Er<sup>3+</sup>-doped fiber DFB laser sensor for differential pressure and force measurements
No full textWe propose and demonstrate a polarimetric Er3+-doped fiber DFB laser sensor where a transversely applied force along the fiber laser induces a birefringence giving rise to a change in the beat-frequency between the two orthogonally-polarized laser modes. We measure a sensitivity of approximately 9.6GHz(N/mm), a wide dynamic range with stable two-mode operation for frequency separations up to 50GHz, and very high sensor resolution owing to the narrow beat frequency bandwidth of <10kHz. The temperature sensitivity is primarily dominated by the temperature dependence of the inherent birefringence, which was measured to be -130kHz/°C. The sensor allows independent pressure/force and temperature measurements
Field statistics modelling of beat noise in an optical amplifier
No full textThe authors present a rigorous and self-contained noise analysis of an optical amplifier based on the statistics of the input source field and the amplified spontaneous emission field of the amplifier. The method enables us to obtain the frequency dependence of the output electrical noise power, which has not been derived in previous studies of optical amplifier noise based on the photon statistics master equation. The authors characterise for the first time the noise of an optical amplifier in combination with a super-fluorescent source, taking into account the frequency dependence of the gain and the presence of optional optical filters
Modeling of polarization mode competition in fiber DFB lasers (corrections to article of 1998)
No full textCorrections to "Modeling of Polarization Mode Competition in Fiber DFB Lasers" (published: IEEE Journal of Quantum Electronics 1998 Vol.34(9) pp.1559-69)
Modelling of polarization mode competition in fiber DFB lasers
No full textA comprehensive model for steady-state analysis of polarization-mode competition in fiber distributed feedback (DFR) lasers is presented. Effects of polarization-dependent grating nonuniformities, polarization-dependent grating strength, coupling between the linear polarization states due to twist or Faraday rotation, back reflections, cross saturation from serially multiplexed lasers, as well as spatially and polarization-dependent gain hole burning are covered by the model. Regimes of single and dual polarization operation are identified for different types of polarization imperfections in the cavity. The output powers of the individual modes and the magnitudes of the hole-burning mechanisms are also calculated and discussed. See also errata published elsewhere
Efficient single-frequency erbium:ytterbium fibre laser
No full textWe report a 7.6mW single-frequency fibre laser operating at 1545nm, using for the first time an Er3+:Yb3+ doped fibre and a fibre grating output coupler. The laser had a linewidth <2.5kHz, and a relative intensity noise (RIN) level below -145dB/Hz above 10MHz
Tunable, single-frequency Er:Yb phospho-silicate fiber Fabry-Perot lasers
No full textTunable erbium:ytterbium phospho-silicate fiber lasers using single- and compound-fiber Fabry-Perot configurations are reported for the first time. Continuous tuning of an ultrashort-cavity laser over 3.33nm and discrete tuning of longer compound-cavity lasers over 5nm are demonstrated
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