Info Qpb
w Baseline 6 dB Loss Outbound Between a Broken Outbound Fiber Between Measurement Amplifiers 128 and 129 Amplifiers 128 and 129 Fig. 3.13 Typical trace from a coherent OTDR COTDR , showing an amplified system signature through several amplifiers at the end of approximately 4500 km. Fig. 3.13 Typical trace from a coherent OTDR COTDR , showing an amplified system signature through several amplifiers at the end of approximately 4500 km. A distinct advantage of loop-back monitoring systems lies in...
Electrooptic Tunable Filters
The electrooptic tunable filter EOTF of Fig. 9.34 is fabricated on x-cut, y-propagation LiNb03 and employs a periodic electrode structure with interdigital finger electrodes of period A, which induce a spatially periodic electric field, E, in the waveguide that couples the TE- and TM-polarized modes by means of the r51 electrooptic coefficient V51 28 X 1012 m V . The TE lt - TM mode conversion is most efficient when the period of the electrode fingers, A, matches the spatial beat period of the...
Acknowledgments
The progress we summarized in this chapter implicitly represents the work of many researchers and developers around the world, and in this short space we were unable to do proper justice to even a fraction of their contributions. We are especially grateful to our colleagues working in this field because each has made a contribution to advancing the technology and has had an influence on our own work. It is our sincere pleasure to acknowledge, in particular, our closest collaborators of many...
Info Hoy
b Dispersion-shifted 4- xm core fiber. c SAE, selective area etching. b Dispersion-shifted 4- xm core fiber. c SAE, selective area etching. Pioneering work in this field was done by Koch and coworkers in 1990 using InGaAs InGaAsP at 1.48 j,m. According to their initial publication, expansion was accomplished by a multilayered structure in which the MQW active layer sat atop a stack of three separate 1.3- u,m waveguide layers, as shown in Fig. 5.13a. Prior to mesa formation, the active region...
Info Hru
tion is that the pump spot size is decoupled from the device length. As a consequence, the high excitation density present in the single-mode core is maintained over the entire device length, which is typically several meters or even tens of meters. This leads to a high degree of flexibility in rare-earth ion concentration that is not possible in bulk up-conversion devices. This flexibility in concentration can be critical in obtaining efficient up-conversion laser operation when there are...
References Ifh
Adar, R., C. H. Henry, C. Dragone, R. C, Kistler, and M. A. Milbrodt. 1993. Broadband array multiplexers made with silica waveguides on silicon. J. Lightwave Tech. 11 212-219. Adar, R C. H. Henry, R. F. Kazarinov, R. C. Kistler, and G. R. Weber. 1992. Adiabatic 3-dB couplers, filters and multiplexers made with silica waveguides on silicon. J. Lightwave Tech. 10 46-50. Adar, R., C. H. Henry, R. C. Kistler, and R. F. Kazarinov. 1992. Polarization independent narrow band Bragg reflection gratings...
I Pump Schemes
The most essential component required for EDFAs, after the erbium-doped fiber, is a pump source to supply light at the correct wavelength i.e., one of the erbium pump bands with adequate power to drive the amplifier. The pump sources for the first EDFA demonstrations were an argon ion laser at 514.5 nm1 and a 670-nm dye laser pumped by an argon ion laser.2 These lasers are complicated, are expensive, and occupy a large fraction of an optical bench. The pump source for a practical EDFA should be...