Date of download: 7/8/2016 Copyright © 2016 SPIE. All rights reserved. (a) Schematic of two parallel identical silicon waveguides with the BCB bonding layer in between. (b) The relationship between the coupling length and the BCB bonding layer thickness. Figure Legend: From: InGaAs PIN photodetectors integrated and vertically coupled with silicon-on- insulator waveguides Opt. Eng. 2014;53(5): doi: /1.OE

Date of download: 7/8/2016 Copyright © 2016 SPIE. All rights reserved. Cross section of an InGaAs PIN photodetector integrated on and vertically coupled with an underlying silicon-on-insulator waveguide. Figure Legend: From: InGaAs PIN photodetectors integrated and vertically coupled with silicon-on- insulator waveguides Opt. Eng. 2014;53(5): doi: /1.OE

Date of download: 7/8/2016 Copyright © 2016 SPIE. All rights reserved. Power-up, power-down efficiency and directionality at 1550 nm as a function of the etch-depth with infinite BOX and BCB layer thickness. The other structure parameters are: filling factor=50%, λ=1550 nm (fixed by tuning the grating period). Figure Legend: From: InGaAs PIN photodetectors integrated and vertically coupled with silicon-on- insulator waveguides Opt. Eng. 2014;53(5): doi: /1.OE

Date of download: 7/8/2016 Copyright © 2016 SPIE. All rights reserved. (a) Dependence of power-up efficiency at 1550 nm on BCB bonding layer thickness and BOX thickness. (b) Dependence of power- up efficiency at 1550 nm on BCB bonding layer thickness without and with SiN anti-reflection layer (BOX thickness fixed at 2 μm). Figure Legend: From: InGaAs PIN photodetectors integrated and vertically coupled with silicon-on- insulator waveguides Opt. Eng. 2014;53(5): doi: /1.OE

Date of download: 7/8/2016 Copyright © 2016 SPIE. All rights reserved. (a) The spectral response of the optimal grating coupler and (b) the electric field distribution of the device with optimal structure. Figure Legend: From: InGaAs PIN photodetectors integrated and vertically coupled with silicon-on- insulator waveguides Opt. Eng. 2014;53(5): doi: /1.OE

Date of download: 7/8/2016 Copyright © 2016 SPIE. All rights reserved. Absorption efficiency of the photodetector with different InGaAs absorption layer thickness. Figure Legend: From: InGaAs PIN photodetectors integrated and vertically coupled with silicon-on- insulator waveguides Opt. Eng. 2014;53(5): doi: /1.OE

Date of download: 7/8/2016 Copyright © 2016 SPIE. All rights reserved. 3-dB bandwidth and absorption efficiency of the present PIN photodetector as InGaAs layer thickness varies. Figure Legend: From: InGaAs PIN photodetectors integrated and vertically coupled with silicon-on- insulator waveguides Opt. Eng. 2014;53(5): doi: /1.OE