title: Dispersion, coherence and noise of Fourier domain mode locked lasers.
abstract: We report on the effect of chromatic dispersion on coherence length and noise of Fourier Domain Mode Locked (FDML) lasers. An FDML laser with a sweep range of 100 nm around 1550 nm has been investigated. Cavity configurations with and without dispersion compensation have been analyzed using different widths of the intra-cavity optical band-pass filter. The measurements are compared to non-FDML wavelength swept laser sources. Based on these observations, a simple model is developed providing a connection between timing, photon cavity lifetime and characteristic time constant of the filter. In an optimized configuration, an instantaneous laser linewidth of 20 pm is observed, corresponding to a 10x narrowing compared to the intra-cavity optical bandpass filter. A relative intensity noise of -133 dBc/Hz or 0.2% at 100 MHz detection bandwidth during sweep operation is observed. For optimum operation, the filter drive frequency has to be set within 2 ppm or 120 mHz at 51 kHz.
authors.affiliation: Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, Munich, Germany.
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Biedermann
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wieser
authors.forename: Christoph M
authors.initials: CM
authors.lastname: Eigenwillig
authors.forename: Thomas
authors.initials: T
authors.lastname: Klein
authors.forename: Robert
authors.initials: R
authors.lastname: Huber
mesh_terms: D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005583:Fourier Analysis; D007834:Lasers; D008027:Light; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity