Dongkyoon Han

Bragg grating-assisted WDM filter for integrated optical triplexer transceivers

We designed and experimentally demonstrated a Bragg grating-assisted wavelength-division-multiplexing filter for the three-wavelength multiplexing on a planar-lightwave-circuit platform. The 1310- and 1550-nm lights were designed to be separated after passing the directional coupler by a half-cycle and a full-cycle coupling actions with losses of 0.07 and 0.19 dB, respectively. The 1492-nm light was reflected back by a Bragg grating fabricated on the directional coupler and its loss was less than 2.0 dB. We also introduced and discussed the new concept of an integrated optical triplexer transceiver using this filter.

Thin film filter-embedded triplexing-filters based on directional couplers for FTTH networks

We designed and experimentally demonstrated a thin film filter (TFF)-embedded directional coupler-type triplexing-filter on the planar-lightwave-circuit platform. The triple-play multiplexing was significantly simplified by using one TFF. The 1.31- and 1.55-/spl mu/m lights were designed to be divided after passing the directional coupler by half-cycle and full-cycle coupling actions, respectively. The 1.49-/spl mu/m light was reflected by a TFF inserted in a trench on the directional coupler. The insertion losses of fabricated triplexing-filters were less than 2.0 dB with bandwidths of 20 nm. The newly proposed triplexing-filter provides a cost-effective high-performance solution for fiber-to-the-home networks.

Reduction of insertion loss of thin film filters embedded in PLC platforms

We propose and experimentally demonstrate a method of reducing insertion loss of a thin-film-filter-embedded planar-lightwave-circuit platform for a triplexer transceiver module. Significant loss reduction was achieved by adding horn waveguide elements at the interfaces between the thin film filter and the output-port (transmission and reflection) waveguides.

Crosstalk enhancement of AWG fabricated by flame hydrolysis deposition method

The crosstalk of arrayed-waveguide grating (AWG) multi/demultiplexer has been reduced through the modification of the torch for flame hydrolysis deposition (FHD) process. The conventional type FHD torch was changed into a precursor-premixed type torch, which enhanced the AWG crosstalk level by 5-8 dB. The results were also compared with the characteristics of AWGs of which the core layers were fabricated by the plasma-enhanced chemical vapor deposition process.

Numerical local-index-integration method of efficient beam propagation simulations

A numerical local-index-integration (NLII) method of the efficient beam propagation simulation and modal analysis of optical waveguides is presented. This method can handle abrupt discontinuities in the refractive index profile quite effectively in a general way that it can be applied to the analysis of inhomogeneous waveguides having various types of index distribution, which conventional index-averaging methods have failed to handle.