Title :
Extremely small multimode interference couplers and ultrashort bends on InP by deep etching
Author :
Spiekman, L.H. ; Oei, Y.S. ; Metaal, E.G. ; Green, F.H. ; Moerman, I. ; Smit, M.K.
Author_Institution :
Dept. of Electr. Eng., Delft Univ. of Technol., Netherlands
Abstract :
We realized the smallest integrated optical multimode interference (MMI) couplers to date by etching through the quaternary guiding layer, maximizing the lateral index contrast, and thus obtaining a sufficient number of guided modes for proper operation despite the small size. Results include a 107 μm long 3 dB coupler with 0.9 dB excess loss and 0.2 dB unbalance, and a 216 μm long cross coupler with 2.0 dB excess loss and -28 dB crosstalk (TE). We also succeeded in making waveguide bends with a record bending radius of only 30 μm and negligible radiation loss.
Keywords :
III-V semiconductors; bending; crosstalk; etching; indium compounds; integrated optics; optical couplers; optical losses; optical waveguides; 0.9 dB; 107 mum; 2 dB; 216 mum; InP; bending radius; cross coupler; crosstalk; deep etching; excess loss; guided modes; integrated optical multimode interference couplers; lateral index contrast; negligible radiation loss; quaternary guiding layer; small multimode interference couplers; small size; ultrashort bends; waveguide bends; Couplers; Etching; Indium phosphide; Interference; Optical crosstalk; Optical interferometry; Optical losses; Optical receivers; Optical sensors; Optical waveguides;
Journal_Title :
Photonics Technology Letters, IEEE
