InGaAsP/InP vertical directional coupler filter with optimally designed wavelength tunability

The design of a broad-electrotuning-range (>73 nm) and narrow-bandwidth ( approximately 1.5 nm) InGaAsP/InP tunable directional coupler filter that uses two vertically coupled asymmetric ridge waveguides is described. The filter operates with both current injection and electrorefraction. This is the widest tuning range reported to date for a semiconductor waveguide filter and is obtained with a moderate current level ( approximately 1.1 kA/cm/sup 2/). The tuning range can be extended to >80 nm if the thermal tuning is included.<
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