Photonics and Optoelectronics Lab

D. H. Kim and Jin U. Kang

We have experimentally investigated temperature dependence of the birefringence of polarization maintaining photonic crystal fiber using Sagnac interferometer configuration. Our results show, for the first time as far as we know, that polarization maintaining photonic crystal fiber has 45 times smaller temperature dependence of birefringence than that of standard polarization maintaining fiber.

Cascaded Raman Self-frequency Shifted Soliton Generation in an Er/Yb-doped Fiber Amplifier

D. H. Kim, Jin U. Kang and Jacob B. Khurgin

The polarization and power dependence of the generation of cascaded Raman self-frequency shifted soliton in Er/Yb-doped fiber amplifier have been experimentally and theoretically investigated. The number of cascaded Raman solitons generated increases as a function of optical pump power of the fiber amplifier. The amount of soliton self-frequency shifts were found to have amplifier power squared dependence, which is predicted by our numerical simulations. Furthermore, the different input polarization condition was found to results in a different amount of soliton frequency shift. The shift was at its maximum when the input light was launched along the either principal axes of the fiber and minimum when the light was launched along the 45 degrees.

Highly stable tunable dual-wavelength Q-switched fiber laser for DIAL applications

Utkarsh Sharma, C. S. Kim and Jin U. Kang

We have demonstrated a novel Q-switched dual-wavelength fiber laser seed source, for application in a DIAL system. The main advantage of the dual-wavelength fiber laser is that only one laser is needed to generate perfectly synchronized two-wavelength pulses.

Optical coherence tomography based on an all-fiber autocorrelator using probe-end reflection as reference

Utkarsh Sharma, N. M. Fried, Jin U. Kang, J. Bush, et al.

Optical coherence tomography (OCT) is a non-invasive optical imaging technique that can be used to perform high-resolution cross-sectional in vivo and in situ imaging of microstructure in transparent as well as opaque biological tissues. We propose and demonstrate a novel, low maintenance, low cost, lightweight, and compact OCT system using an all single mode fiber autocorrelator based scanning system.

Frequency Discriminator based on Ring-Assisted Fiber Sagnac Filter

Gang Chen, Jin U. Kang and Jacob B. Khurgin

We build and experimentally investigate the characteristics of a frequency discriminator based on a ring-assisted fiber Sagnac filter. Compared to a standard Sagnac filter frequency discriminator, the proposed device improves the dynamic range of the filter by 3 dB. This corresponds to a 4 dB improvement in the dynamic range for the recovered RF signals.

Nonlinear Switching and Optical Limiting in Double-Loop Fiber Sagnac Filter

Gang Chen and Jin U. Kang

We investigate all-optical nonlinear switching and optical limiting properties of double-loop fiber Sagnac interferometers with symmetric power splitting. We show that significant nonlinear switching and optical power limiting can occur in this device due to nonlinear polarization rotation in the polarization maintaining (PM) fibers forming the Sagnac loops.

Raman spectroscopy based on frequency doubled Yb-doped fiber laser

Gang Chen and Jin U. Kang

We demonstrate a compact and low-cost Raman spectroscopy based on frequency doubled Yb-doped fiber laser. We test our system with mixture solutions of acetone and water in different mole ratios with good results.