Low pedestal sub-17 fs pulse generation through cascaded self-similar compression in photonic crystal fibers

We propound a realistic numerical model based on cascaded self-similar pulse compression to generate low pedestal ultrashort pulses at 2.5 µm. Self-similarity has been attained by modeling exponential dispersion decreasing and exponentially nonlinearity increasing chalcogenide photonic crystal fibers (PCFs). Initially, fundamental soliton compression in As2S3tapered PCF is investigated for the pedestal-free reduction of the pulse width. Subsequently, the compression factor is further enhanced in the As2Se3 PCF-based nonlinear optical loop mirror. Numerical outcomes reveal a compression of 1 ps pulse down to a pulse width of 16.6 fs with a peak power of 116 W in a total fiber length of L=61 cm.

Development of an Optical Fiber Sensor with a D-shaped Fiber Bragg Grating Integrated in a Loop-mirror Optical Fiber Laser as a High Sensitivity Refractometer

In this paper, we report a new type of refractometer based on a D-shaped fiber Bragg grating (FBG) integrated in a loop-mirror optical fiber laser. This proposed sensor is used in wavelength interrogation method, in which the D-shaped FBG is applied as a refractive index (RI) sensing probe and a mirror to select mode of laser. The D-shaped FBG is prepared by the removal of a portion of the fiber cladding covering the FBG by means of side-polishing technique. The D-shaped FBG sensing probe integrated in a loop-mirror optical fiber laser with saturated pump technique, the characteristics of sensing signals have been improved to obtain stable intensity, narrower bandwidth and higher optical signal-to-noise ratio compare to normal reflection configuration. The limit of detection (LOD) of this sensor can be achieved to 2.95 x 10-4 RIU in the refractive index (RI) range of 1.42-1.44. Accordingly, we believe that the proposed refractometer has a huge potential for applications in biochemical-sensing technique.