Widely Wavelength-Tunable Blue-Shifted Dispersive Waves for Broadband Visible Wavelength Generation in a Photonic Crystal Fiber Cladding

Blue-shifted dispersive waves(DWs)are efficiently generated from the red-shifted solitons by coupling the 120 fs pulses into the fundamental mode of the multi-knots of a photonic crystal fiber cladding.When the femtosecond pulses at the wavelength of 825 nm and the average power of 300 mW are coupled into knots 1–3,the conversion efficiencyηDW of 32%and bandwidth BDW of 50 nm are obtained.The ultrashort pulses generated by the DWs can be tunable over the whole visible wavelength by adjusting the wavelengths of the pump pulses coupled into different knots.It can be believed that this widely wavelength-tunable ultrashort visible pulse source has important applications in ultrafast photonics and resonant Raman scattering.

Performance Investigation of All-Optical NRZ-to-Manchester Format Conversion with SOA-MZI Based XOR Logic Gate

All-optical format conversion between non-return-to-zero(NRZ)and the Manchester code is implemented by using an optical exclusive-OR(XOR)logic gate based on a semiconductor optical amplifier Mach-Zehnder Interferometer(SOA-MZI).There is 10 Gbit/s all-optical NRZ-to-Manchester conversion implemented in our simulation system and BER performance of the format conversion is investigated.Transmission performances of the converted Manchester coded signal are discussed in terms of transmission length and received optical power.

Transmission Performance of the Optical Millimeter-wave Up-conversion Link Using a Phase Modulator

Numerically analyzed is the transmission performance of the optical millimeter （mm）-wave generated by frequency up-conversion via a phase modulator along the dispersive fiber. 60 GHz ram-wave subcarrier（SC） signals can be obtained after fiber transmission, simultaneously, the phase-modulated signals can be converted to the intensity-modulated ones. The numerical results show that the optical ram-wave at fading loops has better performance, and the eye diagram still keeps open when optical mm-wave signal is transmitted over 98 km.

Fabrication of High Quality Broadband Type IIA Chirped Fiber Bragg Gratings

Chirped fiber Bragg gratings have found many applications in optical communication and sensing systems. High quality filters based on chirped fiber Bragg gratings with reflection bandwidth of 2.6 and 32nm and high reflectivity are demonstrated experimentally with 2 and 4cm long phase masks, respectively. These filters with flat reflection band and high reflectivity are achieved by writing type IIA chirped Bragg gratings.

Dynamic OADM Using Tunable Sampled Bragg Gratings Based on Vernier Effect

A novel dynamic optical add-drop multiplexer(OADM) scheme using tunable sampled fiber Bragg gratings(SFBG) by Vernier effect is firstly proposed. In this scheme, broad wavelength tuning range is achieved by only slightly adjusting the SFBG, the wavelength tuning of OADM will be faster than traditional dynamic OADM.

Design for photonic crystal fibers with high nonlinearity and flattened dispersion for self-frequency shift of Raman soliton

A new concept of photonic crystal fiber（PCF） with high nonlinearity and flattened dispersion was designed. The PCF structure is indeed a hexagon lattice. The bigger air holes in the outer rings are used to confine the light field into the core region for enhancing the nonlinearity. The flattened dispersion can be achieved by adjusting the diameters of six smaller air holes in the first ring, and six micro air holes are inserted between smaller air holes for higher nonlinearity and the better flattened dispersion. By optimizing the size of the smaller and micro holes, the PCF can reach to high nonlinearity of 23.3 W-1·km^-1 and the low dispersion of 51.32 ps/（nm·km） with the fluctuation range of 0.98 ps/（nm·km）, which is within the wavelength range of 1 400 nm to 1 900 nm. The designed PCF can be used in important applications in realizing the Raman soliton self-frequency shift（RSSFS）.

Experimental Analysis of a Boron-Codoped Germanosilicate Preform by Use of the Color-Center Model

In this paper we studal the UV-induced refractive index changes of a boron-codoped germanosilicatepreform usedfor foe fabrication of fiber gratings by use Of the color-center model. Two groups of performs, non H2loadedpreform and H2, loadedpreform, are exposed to UV beam of various pulse energy densities and pulse numbers.and their UV-induced excess losses are meosured. The corresponding refractive-index changes are determinedthrough a Kramers-Kroning analysis. Also, our experimental results are discussed and onalyzed according to thecolor-center model of photosensitivity and then some important conclusions are obtained.