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Fiber-in-line Optical Transceiver Using a Silicon V-groove and a Tilted-fiber Gratings
Shinyoung Yoon.
yoonnoah@etri.re.kr
Abstract Text:
There have been strong demands for the cost-reduction of optical transceivers in the optical access systems. Recently, many researchers have focused upon the hybrid-PLC technology. This technology uses mainly the well-established Silicon V-groove technology, silica or polymer waveguide technology, and the surface mounting of LD/PD technology. All processes can be semi-automated and make it possible to provide low-cost transceivers. However, the alignment procedures between PLC waveguides and fiber-butt are time-consuming and the reason of high cost.
In this paper, we propose fiber-in-line type optical transceiver using a silicon V-groove
and a tilted-fiber gratings. A fiber with a tilted grating and 45o angled tip is mounted into a silicon V-groove. The periodicity of gratings is selected for the separation of 1.3um and
1.55um. An LD and PD are mounted on the silicon surface over the V-groove.
In this novel structure, there is no alignment requirement between waveguide and fiber-butt. Therefore, fabrication step reduction and little propagation loss in an in-line fiber instead of a waveguide are expected in our structure.
A V-groove is fabricated by silicon wet-etching processes. The depth of V-groove is designed to 400um. Tilted gratings are made by high power UV-exposure on a Ge-doped fiber. An angled tip is fabricated by a Q-switched laser. The fiber is inserted into a V-groove. An LD with a wavelength of 1.31um is mounted by a flip-chip process over the top of an angled tip on the silicon surface. A PD with a wavelength of 1.55um is mounted over the each top of tilted gratings on the silicon surface. After fabricating, we measure the LI curve for the laser diode. The main reduction of light power is considered due to the poor coupling efficiency between LD and angled tip. Also, we are measuring the BER performance at the bitrate of 155Mbps.
In conclusion, we propose a novel fiber-in-line optical transceiver using a silicon V-groove and a tilted-fiber grating. In our structure, an LD and a PD is integrated directly into a fiber with a tilted grating and an angled tip on a silicon V-groove. Our first fabrication shows the poor coupling efficiency of LD into the fiber. We are improving the coupling efficiency with the angle adjustment and surface roughness. Also, we are measuring the BER performance of the integrated PD.
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