Using four wavelength mixing (FWM) effect in high-nonlinear dispersion-shifted fibre (HNL-DSF), a novel up-conversion technique for binary on-off-key (OOK) radio-on-fibre (ROF) system is proposed in this paper. By injecting a non return-to-zero (NRZ) format data signal and a carrier-suppressed return-to-zero (CSRZ) format carrier signal into HLN-DSF, a signal with a new frequency component generated by FWM effect will have the phase characteristic of CSRZ carrier. The simulation results indicate that the signal has the better transmission performance because of the strong ability of resisting dispersion.
A novel all-optical logic NOR gate is presented that is composed of a semiconductor optical amplifier (SOA) and an optical bandpass filter. The NOR gate is successfully experimentally demonstrated at 40 Gbit/s. The experiment result shows good extinction ratio of larger than 12.0 dB with clear and open eye. The NOR gate has a simple configuration and allows photonic integration.
A novel device of tandem multiple quantum wells (MQWs) electroabsorption modulators (EAMs) monolithically integrated with DFB laser is fabricated by ultra-low-pressure (22 mbar) selective area growth (SAG) MOCVD technique. Experimental results exhibit superior device characteristics with low threshold of 19 mA, output light power of 4.5 mW, and over 20 dB extinction ratio when coupled into a single mode fiber. Moreover, over 10 GHz modulation bandwidth is developed with a driving voltage of 2 V. Using this sinusoidal voltage driven integrated device, 10GHz repetition rate pulse with a width of 13.7 ps without any compression elements is obtained.
Polarization effects such as polarization mode dispersion (PMD) and polarization dependent loss (PDL) have become the critical limiting factors for long haul high bit rate optical fiber transmission. This paper use waveplate models to simulate the statistical performance of optical link with PMD and PDL in 40Gbit/s optical system. Three DPSK modulation formats are compared each other for their tolerance against PMD and PDL. The 33% RZ-DPSK is superior to the other two DPSK formats, the 50% RZ-DPSK and the CSRZ-DPSK whose duty cycle is 67% when only PMD is considered. And in case of PDL, the outages for three DPSK formats do not show obvious changes with the increasing of PDL. Furthermore, the performance of two RZ-DPSK formats, whose duty cycles are 33% and 50% respectively, is superior to that of CSRZ-DPSK. This shows that modulation format with narrower pulse width owns more high tolerance against PMD and PDL, therefore the CSRZ-DPSK format shows poorer performance when it is compared with the other two DPSK formats.
Polarization mode dispersion (PMD) and chromatic dispersion (CD) are two important limiting factors, which affect the performance of high speed fiber transmission system. The tunable PMD and CD compensation experiment on 10Gbit/s NRZ fiber transmission link is reported by using two nonlinear chirp sampling fiber gratings, which are fabricated on high-birefringence and standard single mode fibers by using uniform phase mask. The total system power penalty is less than 1dB (@BER 10-12) after PMD and CD tunable compensation.
The relationships between Degree of Polarization (DOP) and Polarization Mode Dispersion (PMD) for different modulation format signals are discussed not only in theory but also in experiment, which include the NRZ, RZ, CSRZ, DPSK, RZ-DPSK and CSRZ-DPSK signals. The RZ signals with different duty cycle are also analyzed and compared. The results are found that the optical signals DGD/DOP relation depends on their optical spectrum structure as well as the modulation formats, and the phase-shift-keying signal with free chirp will provide better performance in the PMD compensation based on the DOP feedback control because of the DOP sensitivity and wide monitoring window, besides, the CSRZ has the stalest character for the variety of modulation chirp.
In this paper we report a successful experiment of adaptive polarization mode dispersion (PMD) compensation up to second-order in a 40Gb/s optical time-division multiplexed (OTDM) communication system by using two-stage compensator. In the experiment the PMD monitoring technique based on degree of polarization (DOP) was adopted. And the Particle Swarm Optimization (PSO) algorithm was introduced in adaptive PMD compensation, with the desirable features of fast convergence to the global optimum point for compensation without being trapped in local sub-optima and with good robustness to noise. The comparison was made to estimate the performance effectiveness between PSO algorithms with global neighborhood structure (GPSO) and with local neighborhood structure (LPSO). The LPSO algorithm is shown to be more effective to search global optimum for PMD compensation than GPSO algorithm. The ability of tracking changed PMD using PSO algorithm was also investigated. The two-stage PMD compensator is shown to be effective for both first- and second-order PMD, and the compensator is shown to be bit rate independent. The compensation time is within several hundreds of milliseconds. The response time for recovery from a sharp disturbance is about 11ms.
The work presented in this paper gives performance comparisons of Carrier Suppressed Return-to-Zero Differential Phase-Shift Keying (CSRZ-DPSK) with Return-to-Zero Differential Phase-Shift Keying (RZ-DPSK) against both the effects of Intra-Channel Four-Wave Mixing (IFWM) and inter-channel Four Wave Mixing (FWM) in 16×40 Gb/s WDM systems with symmetrical fiber link schemes. IFWM gives smaller phase perturbation to CSRZ-DPSK signal than to RZ33-DPSK, although BER performance of CSRZ-DPSK is worse than that of RZ33-DPSK. The numerical comparison indicates that RZ33-DPSK is a better candidate for 40 Gb/s WDM systems than CSRZ-DPSK.
In this paper, the degradation of signal degree of polarization (DOP) by first and second order polarization mode dispersion (PMD) in 40Gb/s RZ and NRZ optical communication is analyzed by numerical simulation. The simulation results show that the degradation of signal DOP by first order PMD is monotony, but which is fluctuated by second order PMD. The influence of two components of second order PMD on DOP for NRZ code and RZ are also investigated by numerical simulation method. The results also show that the influence of the depolarization component and the PCD component on NRZ and RZ data formats are different. Those results will provide the theory basis for how to select proper compensation arithmetic. A compensation system is founded to compensate the first and high order PMD effectively by DOP as feedback signal and particle swarm optimizer (PSO) as compensation arithmetic. Here, we introduce an intelligent method PSO as a searching algorithm to multi-DOF (degree of freedom) PMD compensation, The PSO algorithm used here is described as: (1) Local neighborhood structure is employed to avoid being trapped into sub-optima. (2) 20 particles are employed. So 20 time units (less than 20 ms) are required in one iteration. (3) The maximum iteration number is set to 50. The experiment result show that the first and second PMD can be compensated at the same times for 10 Gb/s RZ and NRZ by using DOP as feedback signal and PSO as searching algorithm.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.