Fabrication of optical waveguide taper couplers utilizing SiO_2

Abstract

The fabrication of optical waveguide couplers involving tapered layers of SiO(2) is discussed. Details of the photolithographic fabrication processing sequence are presented. This process utilizes carefully controlled etchant undercutting and has been found to be quite reproducible. It has allowed fabrication of tapers having changes in Sio(2) thickness of 1.0,microm over lengths of 55-75 microm. Results are presented which demonstrate taper transverse uniformity for distances of over 600,microm. The smoothness and gradual nature of the tapers are apparent in scanning electron microscope pictures of a taper cross section.

High efficiency light coupling from antiresonant reflecting optical waveguide to integrated photodetector using an antireflecting layer

“…(2) and 3, respectively, using so obtained.' 1 The equivalent index of the guided light neq is defined by Figure 3 shows the propagation characteristics of TE modes of ARROW vs the normalized thickness of the first cladding layer dl/X. Other thicknesses are also normalized by wavelength.…”

“…In the previous sections, we described the calculation of propagation constant and loss by solving the phase equation (1). However, those propagation characteristics do not provide detailed information on the practical behavior of light in the coupling portion where light is radiated to the photodetector, because the previous analysis does not take into account the power distribution of each eigenmode.…”

<title>Optical Channel Waveguide Arrays Coupled To Integrated Charge-Coupled Devices And Their Applications</title>

“…1 each channel waveguide terminates at a detector element where the Si0 region gradually disappears in order to effect coupling of light from the waveguide to the detector element. (12) As light enters each detector element, carriers are excited and collected under each respective isolated section beneath the integration gate shown in Fig. 1.…”