Hybrid integration for beam combining on silicon photonics platform - Optoelectronics Program
Abstract
The objective of this proposal is to transform coherent and wavelength beam combining systems that are conventionally created with bulky, free space optical components into a hybrid integration platform on a single silicon chip. To realize this transformative research, we propose a direct chip-to-chip hybrid integration approach for IIIV gain chips and silicon nitride photonic integrated circuits (PICs) based on passive assembly. The integrated beam combining systems provide on-chip, highly versatile, accurately controlled light sources with either the single frequency or multiple wavelengths for passive PICs and enable a wide range of applications in communication, spectroscopy, and sensing. We propose to design, fabricate, and characterize a novel hybrid photonic platform in silicon to implement both coherent and wavelength beam combining (CBC and WBC). Specifically, we will focus on three research thrusts: 1) We propose a hybrid integration approach that allows for efficient direct chip-to-chip coupling between InP laser diodes and silicon nitride waveguides through simple and cost-effective flip chip bonding. We separately optimize and expand the mode profiles for the laser diodes and silicon nitride waveguides to obtain good mode matching and increase the alignment tolerance in the lateral direction. We create the support pillars in the recessed area on the silicon chip to accurately control the vertical alignment. These efforts together overcome the alignment limitation of passive assembly and achieve excellent optical coupling (<1dB loss) for hybrid integration on a single chip; 2) For the on-chip CBC implementation, we propose to replace the external Fourier cavity that provides the coherent coupling in conventional CBC systems with a PIC coupler array. We will demonstrate that the cross-coupling feedback from the coupler array leads to coherent beam combining of the integrated diode laser array. The miniaturized CBC system not only creates an integrated high power, single wavelength source for passive PICs but also provides for a chip-scale platform to investigate coherent coupling between the laser arrays; 3) We propose to create an integrated WBC system on a silicon chip by replacing the diffraction grating that provides the wavelength multiplexing in conventional WBC systems with an arrayed waveguide grating (AWG). We will show that the AWG simultaneously selects the wavelengths of the integrated laser array elements and combines them. The proposed WBC system provides accurately-controlled, tunable, multiple-wavelength laser sources for passive PICs.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 16, 2018
- Source ID
- W911NF1810176
Entities
People
- Zhu Lin
Organizations
- Army Contracting Command
- Clemson University
- United States Army