Widely tunable picosecond optical parametric oscillator using highly nonlinear fiber

We demonstrated a fully fiber-integrated widely tunable picosecond optical parametric oscillator based on highly nonlinear fiber. The ring cavity with a 50 m highly nonlinear fiber was synchronously pumped with a picosecond mode-locked fiber laser. The tuning range was from 1413 to 1543 nm and from 1573 to 1695 nm, which was as wide as 250 nm. A high-quality pulse was generated with a pulse width narrower than that of the pump. © 2009 Optical Society of America.published_or_final_versio

Picosecond fiber optical parametric oscillator with 500 nm tuning range using dispersion-shifted fiber

We demonstrate a picosecond fiber optical parametric oscillator with a tuning range of 500 nm pumped by a relatively low-cost intensity-modulated pump. Pulses with pulsewidth from 7 ps to 17 ps are generated. © 2010 Optical Society of America.published_or_final_versionThe 2010 Conference on Optical Fiber Communication (OFC), collocated National Fiber Optic Engineers Conference (OFC/NFOEC), San Diego, CA., 21-25 March 2010. In Proceedings of OFC/NFOEC, 2010, p. 1-

A simple 10-GHz picosecond pulse source based on fiber optical parametric oscillator

We demonstrate a simple fully fiber-integrated picosecond optical parametric oscillator based on high-nonlinear dispersion-shifted fiber. High quality picosecond pulses are generated with a 40-nm tuning range. © 2009 IEEE.published_or_final_versio

Wavelength-tunable nearly-transform-limited pulse generation based on fiber optical parametric oscillator

Paper P1.02We demonstrate an all-fiber widely-tunable sub-picosecond fiber optical parametric oscillator based on highly-nonlinear dispersion-shifted fiber. Nearly-transform-limited sub-picosecond pulses are generated over a 60-nm tuning range around 1550 nm. © VDE VERLAG GMBH.published_or_final_versio

Analysis of genetic diversity in Arrhenatherum elatius Germplasm using inter-simple sequence repeat (ISSR) markers

The genetic diversity of 19 Arrhenatherum elatius accessions was analyzed using 100 inter-simple sequence repeat (ISSR) primers, out of which 11 generated distinct amplification products. Out of the 152 total bands detected, 107 were polymorphic. The percentage of polymorphic bands (PPB) was 68.9% with an average of 9.73 polymorphic bands per primer. The ISSR-based genetic similarity (GS) coefficients among the 19 accessions ranged from 0.4821 to 0.7411, revealing high genetic diversity. Based on the UPGMA cluster analysis and the principal components analysis (PCA), the 19 A. elatius accessions were divided into three groups with similar situations. We found that the genetic distance was related to the geographical distance among the 19 A. elatius accessions studied. These results confirm the potential value of genetic diversity preservation for future breeding programs.Key words: Arrhenatherum elatius, genetic diversity, inter-simple sequence repeat (ISSR) markers

Wide-band generation of picosecond pulse using fiber optical parametric amplifier and oscillator

We first demonstrate a wideband generation of picosecond pulse using fiber optical parametric amplifier (FOPA). High quality pulse is generated at 85 nm away from the pump with pulsewidth narrower than that of the pump. We then explore fiber optical parametric oscillator (FOPO) configuration which has the advantage of eliminating the need of seeding laser, leading to a potentially wider wavelength tunability and flexibility. The tuning range of the FOPO is from 1511 nm to 1541 nm and from 1583 nm to 1613 nm, which is as wide as 60 nm, with wavelength span of over 100 nm. Nearly-transform-limited sub-picosecond pulses are generated by this technique. © 2009 IEEE.published_or_final_versio

Tunable repetition rate multiplier based on fiber optical parametric oscillator

We demonstrate a tunable repetition rate multiplier based on fiber optical parametric oscillator. 2-6 times repetition rate multiplication of a 10-GHz pulse source is achieved with a tuning range of 20 nm in the L-band. © 2010 IEEE.published_or_final_versionThe IEEE Photonics Society Summer Topical Meetings, Playa del Carmen, Mexico, 19-21 July 2010. In Proceedings of PHOSST, 2010, p. 133-13

Intelligent spider for Internet searching

As World Wide Web (WWW) based Internet services become more popular, information overload also becomes a pressing research problem. Difficulties with searching on the Internet get worse as the amount of information that is available increases. A scalable approach to support Internet search is critical to the success of Internet services and other current or future national information infrastructure (NII) applications. A new approach to build an intelligent personal spider (agent), which is based on automatic textual analysis of Internet documents, is proposed. Best first search and genetic algorithm have been tested to develop the intelligent spider. These personal spiders are able to dynamically and intelligently analyze the contents of the users' selected homepages as the starting point to search for the most relevant homepages based on the links and indexing. An intelligent spider must have the capability to make adjustments according to progress of searching in order to be an intelligent agent. However, the current searching engines do not have communication between the users and the robots. The spider presented in the paper uses Java to develop the user interface such that the users can adjust the control parameters according to the progress and observe the intermediate results. The performances of the genetic algorithm based and best first search based spiders are also reported.published_or_final_versio

Fast and wide tuning wavelength-swept source based on dispersion-tuned fiber optical parametric oscillator

We demonstrate a dispersion-tuned fiber optical parametric oscillator (FOPO)-based swept source with a sweep rate of 40 kHz and a wavelength tuning range of 109 nm around 1550 nm, The cumulative speed exceeds 4,000,000 nm/s. The FOPO is pumped by a sinusoidally modulated pump, which is driven by a clock sweeping linearly from 1 to 1.0006 GHz. A spool of dispersion-compensating fiber is added inside the cavity to perform dispersion tuning. The instantaneous linewidth is 0.8 nm without the use of any wavelength selective element inside the cavity. 1 GHz pulses with pulse width of 150 ps are generated. © 2010 Optical Society of America.published_or_final_versio

Subpicosecond fiber optical parametric chirped pulse amplifier based on highly-nonlinear fiber

We experimentally demonstrate a fiber optical parametric chirped pulse amplifier. A 750-fs signal is stretched to 40 ps, amplified with a gain of 30 dB through parametric process and then compressed to 808 fs. 2010 Optical Society of America. © 2010 IEEE.published_or_final_versionThe 2010 Conference on Lasers and Electro-Optics (CLEO) and Quantum Electronics and Laser Science Conference (QELS), San Josa, CA., 16-21 May 2010. In Proceedings of the CLEO/QELS, 2010, p. 1-