A novel dispersion compensating fiber with multiple windows is firstly proposed. The proposed DCF is based on hybrid
photonic crystal fiber. This type of DCF gets a multiple negative dispersion windows by the coupling between the hybrid
guiding mode in the edge of each band-gap and the index guiding mode in the cladding deficit area. This is very different
from the ordinary dual-core mechanism. This proposed DCF can be widely used in dispersion compensating system, the
photonic generation of UWB signals, the pulse forming system and the compressing of optical soliton.
A novel highly birefringent photonic crystal fiber with selectively liquid-filled structure in cladding is proposed. The birefringence is numerically investigated with variant structural parameters and refractive index of the infiltrating liquid. The results show that high birefringence can be achieved over a wide wavelength range, and the birefringence is increased because of the symmetry destroyed further in the proposed structure. However, the confinement loss keeps the same order of magnitude even though more materials with high refractive index are filled in the cladding. By varying the refractive index of the infiltrating liquid, the birefringence is shown to be well tuned. It has the potential to be used as optical devices such as all-fiber polarization controllers and high-sensitive sensors.
A novel highly birefringent photonic crystal fiber (PCF) with hybrid cladding is proposed. In this hybrid structural PCF,
some air holes of the cladding are selectively filled with high refractive index material. The increased birefringence
mainly results from that the symmetry is destroyed further in the designed PCF. The birefringence is theoretically
investigated with variant structural parameters and refractive index of the filled material. The plane wave expansion
method (PWE) and full-vector finite-element method (FEM) are respectively employed to investigate the optical
properties of the proposed PCF. The numerical results show that the designed PCF can provide high birefringence and be
well tuned by the structural parameters and refractive index of the filled material. It can be used as all-fiber polarization
controllers and highly sensitive sensors.
The fiber Bragg grating has been widely used in sensors. We have studied the spectral properties of uniform Bragg gratings in photonic crystal fibers under transverse pressure. By the finite element method, the relation between the birefringence and the pressure was simulated in bare photonic crystal fibers. The results show that the birefringence is changed even under weak pressure. A new method based on polarization-dependent loss is presented for measuring pressure. The maximal amplitude of the polarization-dependent loss varies linearly in the pressure range of 0 to 4 MPa with a slope of 0.75 MPa−1.
Two-mode highly birefringent optical fibers support two spatial modes. The two spatial modes can be used to set up two
detectors. The birefringence would change with the variety of environment. Therefore, two-mode highly birefringent
optical fibers can sense two parameters synchronously. A finite element method (FEM) was used to numerically
calculate the distribution of pressure, distribution of temperature and the birefringence variety versus pressure and
temperature in two-mode highly birefringent photonic crystal fibers. Based on the single parameter sensor, the
muti-parameter sensor was analyzed. The results show that the muti-parameter sensor can measure pressure and
In this paper, dispersion compensating photonic crystal fiber with triple-cladding is put forward and the property of high negative dispersion is investigated. Plane-wave expansion (PWE) method is used to analyze. We discuss the variation of the dispersion in detail, with changing the geometry parameters. A triple-cladding dispersion compensating photonic crystal fiber with dispersion -4140 ps/nm/km and FWHM 10 nm is demonstrated at 1550 nm wavelength.
Dual Head Pulse Interval Modulation (DH-PIM) is a modulation technique using in optical wireless communications. In this paper, the performance of DH-PIM is analyzed in the presence of intersymbol interference. The channel impulse response and symbol error rate versus normalized delay spread are discussed. A soft-decision decoding technology is presented, which can improve the performance of DH-PIM.
In the optical wireless communications systems, modulation schemes such as PPM, DPPM are often used because of its power efficiency. This paper presents a modified DPPM modulation technique for optical wireless communication. We study the properties of IDPPM and compare the power and bandwidth efficiency of OOK, PPM, DPPM and IDPPM. Also we analyse the packet-error probability on ideal distortionless channels with AWGN and examine the detection technology of the system. Finally we show the improving of performance using IDPPM modulation.