No abstract

We experimentally demonstrate a superluminal space-to-time mapping process in grating-assisted (GA) codirectional coupling devices, particularly fiber long period gratings (LPGs). Through this process, the grating complex (amplitude and phase) apodization profile is directly mapped into the device's temporal impulse response. In contrast to GA counterdirectional couplers, e.g., Bragg gratings, this mapping occurs with a space-to-time scaling factor that is much higher than the propagation speed of light in vacuum. This phenomenon has been used for synthesizing customized complex optical pulse data sequences with femtosecond features (3.5 Tbit/s data rate) using readily feasible fiber LPG designs, e.g., with subcentimeter resolutions.

We report the experimental realization of an ultrafast (terahertz-bandwidth) linear optical signal processor, particularly a picosecond flat-top optical pulse shaper, based on a fiber Bragg grating (FBG) working in transmission. The used FBG design technique, based on a specially apodized linearly chirped FBG, enables the synthesis of readily feasible devices with processing bandwidths well in the terahertz range. The specific device reported here is successfully demonstrated for reshaping ultrashort (400 fs FWHM) optical Gaussian-like pulses into 2 ps flat-top pulses.

We demonstrate a dual-band Tm 3+ :ZBLAN fiber laser emitting simultaneously at 810 nm and 1487 nm through two transitions originating from the 3 H 4 energy level. Upconversion pumping at 1064 nm is used.

No abstract