L. Morl et al., UNCLADDED INGAASP INP RIB WAVE-GUIDES WITH INTEGRATED THICKNESS TAPERS FOR EFFICIENT FIBER-CHIP BUTT COUPLING/, Electronics Letters, 32(1), 1996, pp. 36-38
The thickness of the waveguide core of uncladded InGaAsP/InP rib waveg
uides is tapered to fabricate new spot-size transformers without epita
xial regrowth or etching of deep grooves. The coupling loss for flat-e
nd fibres is reduced by 7 dB at alignment tolerances of > +/-2 mu m fo
r 1 dB excess loss.