Photonic integration in indium-phosphide membranes on silicon (IMOS)

Abstract

A new photonic integration technique is presented, based on the use of an indium phosphide membrane on top of a silicon chip. This can provide electronic chips (CMOS) with an added optical layer (IMOS) for resolving the communication bottleneck. A major advantage of InP is the possibility to integrate passive and active components (SOAs, lasers) in a single membrane. In this paper we describe progress achieved in both the passive and active components. For the passive part of the circuit we succeeded to bring the propagation loss of our circuits close to the values obtained with silicon; we achieved propagation loss as low as 3.3 dB/cm through optimization of the lithography and the introduction of C-60 (fullerene) in an electro resist. Further we report the smallest polarisation converter reported for membrane waveguides (< 10 mu m) with low-loss (< 1 dB from 1520-1550 nm), >95% polarisation conversion efficiency over the whole C-band and tolerant fabrication. We also demonstrate an InP-membrane wavelength demultiplexer with a loss of 2.8 dB, a crosstalk level of better than 18 dB and a uniformity over the 8 channels of better than 1.2 dB. For the integration of active components we are testing a twin guide integration scheme. We present our design based on optical and electrical simulations and the fabrication techniques

Advanced Integration Techniques on Broadband Millimeter-Wave Beam Steering for 5G Wireless Networks and Beyond

“…22. The cross-section structure of the (a) III-V/Si hybrid platform [99], [100], (b) III-V membrane platform with lateral active junction and low-indexcontrast waveguides [101] and (c) III-V membrane platform with vertical active junction and high-index-contrast waveguides [102]. available and capable for beam steering application.…”

“…The hybrid photonic platforms where one or more photonic layers are integrated with EICs appear to be a promising solution. Several hybrid schemes exist and can be categorized in two types: III-V/Si hybrid integration [99], [100] and III-V membrane integration [102], [104]. The schematic diagrams of the cross-section geometry for those schemes are depicted in Fig.…”

“…The optical buffer layer between substrate and membrane made with low index material ensures the maximized optical confinement. As a result, the passive waveguides in both platforms can have a crosssection area of only 0.1 to 0.2 μm 2 [102], [105], and a bending radius of only few μm. This greatly reduces the footprint of the passive photonic components by at least a factor of ten.…”

Vertical and Smooth Single-Step Reactive Ion Etching Process for InP Membrane Waveguides

“…3 The intrinsic advantage of InP and its related compound material system allow for co-integration of a monolithic photonic layer with both active and passive functionalities on top of control electronics using an adhesive bonding technique. 4 The dimensions of IMOS optical waveguides scale down dramatically as compared to traditional InP optical waveguides, 2 therefore the optical modes in the waveguide will experience higher losses due to much stronger interaction with the surroundings. A significant part of the optical loss comes from the roughness introduced during the processing of the membrane waveguide, especially from the lithography and the dry etching.…”

“…The InP membrane on Si (IMOS) 1,2 is regarded as the nextgeneration generic InP photonic integration platform. 3 The intrinsic advantage of InP and its related compound material system allow for co-integration of a monolithic photonic layer with both active and passive functionalities on top of control electronics using an adhesive bonding technique.…”