A long InGaAsP/InP waveguide section with small dimensions

A spirally folded InGaAsP/InP ridge-type waveguide with 12.4 mm length, corresponding to 4-cm free-space length, on a device area of 1 mm*1 mm, was realized. Insertion loss was measured to be 4 dB for TE-polarization and 4.5 dB for TM-polarization, most of which is caused by normal propagation loss (2 dB/cm for straight waveguides). Excess bending loss is estimated to be 1.5 dB for TE and 2 dB for TM-polarization.<
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