P. Albrecht et al., INTEGRATION OF POLARIZATION-INDEPENDENT MODE TRANSFORMERS WITH UNCLADDED INGAASP INP RIB WAVE-GUIDES/, Electronics Letters, 32(13), 1996, pp. 1196-1198
Polarisation independent mode transformers were fabricated by Corp thi
ckness tapering in uncladded InGaAsP/InP rib waveguides intended for i
ntegration into PICs. No epitaxial regrowth is needed. The coupling lo
ss for flat-end fibres is reduced to (2.3 +/- 0.2) dB at alignment tol
erances of > +/- 2.4 mu m for 1 dB excess loss.