We proposed a new structure for fiber lens to extend the working distance by applying polymer layer to the fiber lens.
The simulation result shows that the working distance can be extended to larger than 10 times than a fiber lens without a
coated layer. In simulation, the proposed structure extended the working distance to about 2,110 μm by using polymer
layer with a refractive index of 1.3.
For optical clock recovery of nonreturn-to-zero (NRZ) signals more than 40 Gb/s, we propose and experimentally demonstrate a simple clock recovery scheme using beat processing. Through the proposed scheme, we square the adjustment range of the variable optical attenuator (VOA) and achieved an enhanced clock-to-noise ratio (CNR) of more than 15 dB in the experiment, compared to a system without the proposed scheme.
Laser energy distributions of 20 μm and 40 μm glass microspheres were calculated with different laser wavelengths. Most simulation results show similar energy distributions in which laser energies are focused at the backside of the microsphere. Using time-resolved optical shadow images and Schlieren images, initial breakdown location and shockwave propagation from the breakdown were investigated for 20 μm glass microsphere which was ablated by Nd:YAG laser with a wavelength of 1.064 μm. Time-resolved imaging showed the location of the initial breakdown and the shockwave motion over its first 300 μm of expansion. Measured shockwave velocities were in the range of 1-10 km/s and showed a linear dependence on laser fluence within 30 ns.