Ofs Fitel, LLC

Philip G Westergaard

Jeffrey W Nicholson

Poul Kristensen

An all-fiber supercontinuum (SC) optical source utilizes a combination of a seed pulse supply of short-duration optical pulses with a highly non-linear optical medium in the form of two or more concatenated sections of highly non-linear optical fiber (HNLF) of different dispersion values and lengths. The two or more sections of HNLF are configured to include at least one section that exhibits a positive dispersion value and one section that exhibits a negative dispersion value. Non-linear effects such as self-phase modulation (SPM), cross-phase modulation (XPM), Raman amplification, and the like, cause the seed pulses to broaden as they propagate through each section of HNLF, where the differences between the dispersion values, as well as the lengths of each fiber section, are particularly configured to create an SC output that is wide and smooth, exhibiting a stable intensity and high coherence level.

Fiber-based supercontinuum light source

A specialized, dispersion-controlled fiber is particularly configured to exhibit a relatively uniform dispersion (D) over a broad spectral range (for example, 1000 nm to 2000 nm). The specialized fiber exhibits an essentially constant attenuation (&#x3b1;) over this same spectral range so that the fiber is defined as having a high 'figure of merit' (FoM) where FoM is defined as |D|/&#x3b1;. The specialized fiber is well-suited for use as a pulse stretcher, providing the ability to separate out wavelength constituents of an extremely short (fs, ps) broadband pulse into the ns range, for example.

Optical fiber with specialized figure-of-merit and applications therefor

A self-starting, passively modelocked figure-8 fiber laser is specifically configured to self-start into a low noise mode by controlling one or more operating parameters of the laser including, but not limited to, the coupling ratio between the uni-directional fiber loop and the bi-directional mirror loop, the accumulated dispersion within the figure-8 structure, and the amount of power present in the laser cavity. A self-starting passive modelocked figure-8 laser may also be made to self-start by initially increasing the pump current above its lasing threshold. Including a band-pass filter in the uni-directional loop has been found to ensure that the laser will enter a low noise lasing mode.

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Frederiksberg C, Denmark

Philip G Westergaard