Ultra fabrication-tolerant fully packaged micro-optical polarization diversity hybrid

Abstract

Abstract-We report on a novel fully packaged micro-optical polarization diversity hybrid, which shows excellent performance in combination with large fabrication and assembly tolerances. Our novel design employs highly parallel glass plates, which results in parallel and equidistant input and output beams. Critical fabrication and alignment procedures are thus avoided. At the target wavelength of 1.55 pm, typical fiber-to-fiber insertion loss is 0.7 dB, balancing is 50 f3%, polarization extinction ratios are better than 25 dB, and measured optical back reflection is smaller than -58 dB. Wavelength insensitive behavior has been observed, resulting in a wide usable spectral operating range in excess of 90 nm. The micro-optical hybrid has been successfully tested in a dual-balanced polarization-diversity coherent CPFSK transmission experiment at 2.5 Gbt/s.

Integrated-optic versus microoptic devices for fiber-optic telecommunication systems: a comparison

“…The example on top (a) shows a hybrid which contain microoptics and waveguide optics, packaged together with a quad PIN detector [37]. At the bottom, an example is illustrated (b) where critical angle alignments of each expanded beam fiber interface have been avoided owing to a design based on a stack of glass plates with parallel surfaces [46].…”

“…A different approach minimizing both fabrication and alignment procedures was reported by Philips [46]. This resulted in a high performance hybrid which combines compact size, insertion loss of 0.7 dB, polarization extinction ratio of 25-42 dB, balancing 50% 3%, reflection of less than 58 dB, and usable bandwidth of over 90 nm.…”