Method of making tapered semiconductor waveguides

Abstract

Abstract Adiabatic mode control and structural reproducibility are achieved by a tapered semiconductor waveguide structure wherein semiconductor guiding layers are interleaved with stop-etch layers and each guiding layer extends further along the propagation axis of the waveguide further than the guiding layer immediately adjacent thereabove to create a staircase-like core or guiding structure. Cladding regions of appropriate semiconductor material having a lower index of refraction than the tapered core structure may be added to completely surround the tapered guiding structure. The profile of the tapered structure is realizable as any desired staircase-like shape such as linear, parabolic, exponential or the like. Additional layers of higher index of refraction semiconductor material may be included in the cladding region to permit additional beam shaping of the expanded spatial mode propagating along the tapered waveguide. Photolithographic masks defining successively larger exposed areas are aligned, deposited over the waveguide structure, and then removed following each etching step. Material selective etching techniques are employed to remove exposed (unmasked) portions of guiding layers. In sequence, the exposed, formerly underlying portions of the stop-etch layers are then removed using material selective etching. Iteration of the above process steps permits a tapered waveguide structure to be defined.

Inventors

• 👤 Thomas L. Koch
• 👤 Uziel Koren

Bibliographic Details