Dense Wavelength Division Multiplexing Fiber Research Articles

Compact and portable 100-GHz microresonator-based optical frequency comb generation system for dense wavelength division multiplexing fiber optic communication

A compact and portable microresonator-based optical frequency comb generation system was developed to provide an array of multiwavelength laser sources for dense wavelength division multiplexing (DWDM) fiber optic communication. The reported comb generation system was capable of producing comb lines after 7 km of travel without environmental control, indicating the effectiveness of the packaging. The comb spacing is about 98.3 GHz (i.e., ∼0.79 nm around 1553 nm), thus the comb line frequencies coincide nicely with 100-GHz DWDM channel frequencies, assuming the suggested channel bandwidth is 0.3 nm. The quality of selected comb lines was evaluated individually based on error vector magnitude (EVM) measurements along with RF spectrum measurements. An average EVM value observed is as low as 3.8%, close to typical EVM values of less than 3% used for fiber optic communication.

Design of multichannel DWDM fiber Bragg grating filters by Lagrange multiplier constrained optimization

We present the synthesis of multi-channel fiber Bragg grating (MCFBG) filters for dense wavelength-division-multiplexing (DWDM) application by using a simple optimization approach based on a Lagrange multiplier optimization (LMO) method. We demonstrate for the first time that the LMO method can be used to constrain various parameters of the designed MCFBG filters for practical application demands and fabrication requirements. The designed filters have a number of merits, i.e., flat-top and low dispersion spectral response as well as single stage. Above all, the maximum amplitude of the index modulation profiles of the designed MCFBGs can be substantially reduced under the applied constrained condition. The simulation results demonstrate that the LMO algorithm can provide a potential alternative for complex fiber grating filter design problems.

A new design for non-zero dispersion-shifted fiber (NZ-DSF) with a large effective area over 100 μm 2 and low bending and splice loss

A new design for large-effective-area non-zero dispersion-shifted fiber (NZ-DSF) for dense wavelength division multiplexing (DWDM) is presented. The Gaussian approximation method is used for calculating electrical field distribution for the designed refractive index profile. The designed fiber has a dispersion about 4 ps/nm/km and dispersion slope about 0.06 ps/nm 2/km at 1.55 μm operating wavelength, which can be used to avoid four-wave mixing (FWM). In addition, our calculation also shown that the designed fiber not only has a large effective area over 100 μm 2 but also has low bending loss (<1.3×10 −3 dB with 30 mm bending radius and 100 turns) and low splice loss (<6.38×10 −3 dB) with conventional fiber. The manufacturing tolerance of the fiber is found to be compatible with other types of known profile large-effective-area fibers. Thus, this newly designed fiber may be a good candidate for the long-haul DWDM fiber optic communications.

Applications of Organic and Inorganic Optical Thin Films in Telecommunications

The demands of exponentially growing Internet traffic, coupled with the advent of Dense Wavelength Division Multiplexing (DWDM) fiber optic systems to meet those demands, have triggered a revolution in the telecommunications industry. In the three short years of deployment, DWDM performance has accelerated dramatically. Channel counts have grown from 4 to 80, with 170 announced, and channel spacings have shrunk from 400 GHz to 50 GHz. Practical systems that put 1 TeraBit/sec. of information on a fiber are now on the horizon. This dramatic increase has been built upon, and has driven, improvements in fiber optic component technology, which has in turn driven improvements in photonic materials. The next generation of systems for the “all optical network” will require higher performance components coupled with dramatically lower costs. One approach to achieve significantly lower costs per function is to employ Planar Lightwave Circuits (PLC) to integrate multiple optical functions on a single substrate leading to a single package. In this way multiple components can be fabricated and interconnected at once, significantly reducing both the manufacturing and the packaging/assembly costs. The manufacture of PLCs, however, places demanding requirements on materials, design and fabrication processes. Parameters such as index of refraction, absorption and birefringence must be tightly controlled. PLCs have been made using inorganic crystals, such as Lithium Niobate, oxide glasses or polymers on silicon substrates and semi-conductor materials, such as Indium Phosphide (InP). All except InP are commercially available. In this paper we give an overview of the applications of PLCs in DWDM fiber optic transmission systems and discuss how material's requirements flow down from end-use requirements. The specific example of the use of polymer based thermo-optic switches for reconfigurable Optical Add/Drop Multiplexer (OADM) applications is discussed.