Proceedings Article | 6 July 2006
Proc. SPIE. 6350, Workshop on Optical Components for Broadband Communication
KEYWORDS: Photonic integrated circuits, Waveguides, Fiber to the x, Transceivers, Polymers, Integrated optics, Optics manufacturing, Semiconductor lasers, Diodes, Thin films
"Berlin Access", a regional R&D project carried out by six companies and Heinrich Hertz Institute, Fraunhofer
Society, is geared towards low cost solutions for fibre access network architectures (PON and CWDM-PON), ONU
transceivers, and passive fibre components. Close communication with system manufacturers, non-incumbent
carriers, and a city services supplier implementing a local FTTH network supports orientation towards market
demands. In this paper we report on a new FTTH transceiver based on an all-polymer PLC motherboard. The
waveguides exhibit high transmission, strong optical confinement, and large operation temperature range. Low loss
passively adjusted fibre/PLC coupling is achieved by employing a waveguide taper. Downstream/upstream
wavelength separation is accomplished by a directional coupler, or, alternatively, a thin film filter inserted into the
input/output waveguide (the latter approach also allowing for the provisioning of an overlay broadcasting channel).
The horizontal-cavity surface-emitting laser diode, the pin-photodiode (equipped with a thin film filter for improved
crosstalk suppression), and the monitor diode are all flip-chip surface mounted; the light being coupled via 45°
waveguide mirrors. Chip mounting can be done with a commercial fineplacer using semi-active automatic
alignment. Micro-strip lines with impedances adapted to both laser and photodiode are fabricated on the basis of the
PLC films. The polymer motherboard integration scheme offers compact transceiver optical subassemblies and lends
itself favourably to highly automized, low cost manufacturing with high yield. Extended functionalities like loss of
light alarm or concepts for colourless CWDM ONUs can be easily realized with this concept.
