Erbium-doped fiber amplifiers are modeled using the propagation and rate equations of a homogeneous two-level laser medium. Numerical methods are used to analyze the effects of optical modes and erbium confinement on amplifier performance, and to calculate both the gain and amplified spontaneous emission (ASE) spectra. Fibers with confined erbium doping are completely characterized from easily measured parameters: the ratio of the linear ion density to fluorescence lifetime, and the absorption of gain spectra. Analytical techniques then allow accurate evaluation of gain, saturation, and noise in low-gain amplifiers (G >

Modeling erbium-doped fiber amplifiers

A device capable of demultiplexing Tb/s pulse trains that requires less than 1 pJ of switching energy and can be integrated on a chip is presented. The device consists of an optical nonlinear element asymmetrically placed in a short fiber loop. Its switching time is determined by the off-center position of the nonlinear element within the loop, and therefore it can use the strong, slow optical nonlinearities found in semiconductors, which all other fast demultiplexers seek to avoid. The switch's operation at 50 Gb/s is demonstrated, using 600-fJ control pulses. >

A terahertz optical asymmetric demultiplexer (TOAD)

We introduce a traffic model for circuit switched all-optical networks (AONs) which we then use to calculate the blocking probability along a path for networks with and without wavelength changers. We investigate the effects of path length, switch size, and interference length (the expected number of hops shared by two sessions which share at least one hop) on blocking probability and the ability of wavelength changers to improve performance. Our model correctly predicts unobvious qualitative behavior demonstrated in simulations by other authors.

Models of blocking probability in all-optical networks with and without wavelength changers

We describe recent results of the Advanced Research Projects Agency (ARPA) sponsored Consortium on Wideband All-Optical Networks which is developing architectures, technology components, and applications for ultrafast 100 Gb/s time-division multiplexing (TDM) optical networks. The shared-media ultrafast networks we envision are appropriate for providing low-access-delay bandwidth on demand to both future high-burst rate (100 Gb/s) users as well aggregates of lower-rate users (i.e., a heterogeneous user population). To realize these goals we are developing ultrafast network architectures such as HLAN, described here, that operate well in high-latency environments and require only limited processing capability at the ultrafast bit rates. We also describe results on 80-Gb/s, 90-km soliton transmission, 100-Gb/s soliton compression laser source technology, picosecond short-pulse fiber ring lasers, picosecond-accuracy optical bit-phase sensing and clock recovery, all-optical injection-locked fiber figure-eight laser clock recovery, short-pulse fiber loop storage, and all-optical pulse width and wavelength conversion.

All-Optical Network Consortium-ultrafast TDM networks

Integration of the whole mode-locked laser onto a single piece of semiconductor offers a number of advantages, including total elimination of optical alignment processes, improved mechanical stability, and the generation of short optical pulses at much higher repetition frequencies. Semiconductor laser processing technologies were used to implement the colliding-pulse mode-locking (CPM) scheme, which is known to effectively shorten the pulses and increase stability, on a miniature monolithic semiconductor cavity. The principles of and recent progress in monolithic CPM quantum-well lasers are reviewed. >

Monolithic colliding-pulse mode-locked quantum well lasers

All-optical demultiplexing has been shown with a full-duty-cycle 2.5-Gbit/s signal in a nonlinear fiber Sagnac interferometer. Complete switching of arbitrary pulse patterns in the data stream has been achieved by using two orthogonal polarization states for the switching and switched pulse trains. The polarization dispersion between the two fiber axes defines a window that allows for switching with timing errors as large as 350 ps.

All-optical arbitrary demultiplexing at 2.5 Gbits/s with tolerance to timing jitter.

Spectral gain hole-burning was observed at low temperatures in an erbium-doped fiber amplifier with GeO/sub 2/:SiO/sub 2/ core. At the peak wavelength lambda =1.535 mu m, homogeneous linewidths determined from the observed hole widths have a power-law dependence on temperature. At room temperature, the extrapolated homogeneous linewidth is 4 nm and the inhomogeneous linewidth is 8 nm. >

Determination of homogeneous linewidth by spectral gain hole-burning in an erbium-doped fiber amplifier with GeO/sub 2/:SiO/sub 2/ core

Relative gain differences among channels in WDM-amplified lightwave systems can be corrected in two-stage fiber amplifiers having complementary gain spectra in each stage. With two channels spaced by 2.5 nm, relative gain corrections of 1 dB were demonstrated. Simulations show that this method can be used to dynamically equalize the channel gain in long-distance transmission systems. >

Dynamic gain equalization in two-stage fiber amplifiers

All-optical arbitrary demultiplexing at 2.5 Gb/s with tolerance to timing jitter.

Reflective optical amplifier configurations based on circulators provide improved performance compared to their single-ended- topology counterparts. Besides better pump efficiency,1 the multistage reflective amplifiers offer possibilities for gain-equalization means,2 ASE filtering, add–drop functions,3 and dispersion compensation.4

D. J. Di Giovanni

Papers

All-optical arbitrary demultiplexing at 2.5 Gbits/s with tolerance to timing jitter.

Determination of homogeneous linewidth by spectral gain hole-burning in an erbium-doped fiber amplifier with GeO/sub 2/:SiO/sub 2/ core

Dynamic gain equalization in two-stage fiber amplifiers

All-optical arbitrary demultiplexing at 2.5 Gb/s with tolerance to timing jitter.

Multistage EDFA-circulator-based designs