A chirped, phase-shifted structure is demonstrated for compact multi-wavelength DFB fiber laser at room temperature for the first time. The chirped structure provides separated resonance cavities and then the stable multi-wavelength operation. The equivalent phase shift method is demonstrated to realize the desired chirp and phase shifts simply and flexibly. A 44pm-spaced, dual-wavelength DFB fiber laser is then achieved experimentally, which is the narrowest spacing ever reported for a compact multi-wavelength fiber laser.
In this paper, the index guide and band gap guide polymer microstructured optical fibers are designed. For the index guide fiber, a liquid crystal core is used and 60dB extinction ratio tunable attenuator is obtained. For the bandgap polymer microstructured optical fibers, a regular structure is presented from experiment and an ideal defect can be realized easily by a new method.
Polarization mode dispersion can decrease the performance of the fiber-optic transmission seriously. Thus the compensation of Polarization mode dispersion is a critical issue in fiber optics. In this paper, a novel Polarization mode dispersion compensator is suggested and demonstrated based on a special-design fiber Bragg grating. A polarization mode dispersion compensation grating with 10-156ps dynamical span and flat-top response is first reported based on the combination of reconstruction algorithm and the equivalent-chirp method. A 10-Gb/s system experiment using the tunable PMD compensator shows the power penalty of BER at is about 1.2dBwhen the PMD of the system is 60ps.
A cost-effective tunable dispersion compensator using reconstruction-equivalent-chirp method is fabricated. Only uniform phase mask, sub-micron precision and uniform thin metal film are required in the fabrication. The group delay ripple is less than 14 ps during the whole tuning range. An experiment in 40-Gb/s system is demonstrated with a power penalty of 0.7dB.