Polymer integrated optical devices for telecommunications applications

The success of optical fiber technology continues to enable great advances in telecommunications. Among the more recent commercial developments have included the erbium doped fiber amplifier, 10 GB/sec time division multiplexing, and dense wavelength division multiplexing (DWDM). In the near future two trends will dominate the continued growth of this technology (1) increased optical device functionality and (2) migration of increased bandwidth down to local loop and access levels of the network. Examples of increased functionality will include splitters and DWDM's with increased port counts, wavelength conversion, and matrix optical switching. Migration of bandwidth will require greater volumes of fundamental optical components such as power splitters and WDM's. We will discuss our polymeric optical device technology in light of both current and future telecom needs. We have developed a series of cross-linked polymers with intrinsic losses in the 1.55 μm window as low as 0.1-0.2 dB/cm. Singlemode waveguides can be made from these materials by photolithography or by molding. Our baseline materials, C20 and C21, are nonhalogenated polymers and exhibit waveguide losses at 1.55 μm of 1 to 1.5 dB/cm; by increasing the level of halogenation we can achieve waveguide losses as low as 0.3 dB/cm. These polymers exhibit excellent resistance to adverse environmental conditions, typified by the well-known Bellcore 85°C/85%RH soak test. 1 × 16 and 1 × 8 power splitting devices made from C20/C21 have exhibited insertion losses of 11 dB and uniformities of ± 0.3 dB at 1.3 μm. We have also invented a passive alignment technology that allows optical fibers to be "snap-fit" aligned with the optical waveguide, which reduces the difficulty and cost of pigtailing. Finally, we discuss our approach to DWDM which takes advantage of our ability to precisely control the refractive index of our polymers by proper selection of the comonomers.