Silicon-on-insulator is an attractive choice for developing mid-infrared photonic integrated circuits. It benefits from mature fabrication technologies and integration with on-chip electronics. We report the development of SOI channel and rib waveguides for mid-infrared wavelengths centered at 3.7 μm. Propagation loss of ∼1.44 dB/cm and ∼1.2 dB/cm has been measured for TE and TM polarizations in channel waveguides, respectively. Similarly, propagation loss of ∼1.39 dB/cm and ∼2.82 dB/cm has been measured for TE and TM polarized light in rib waveguides. The propagation loss is consistent with the measurements obtained using a different characterization setup and for the same waveguide structures on a different chip. Given the tightly confined single-mode in our 400 nm thick Si core, this propagation loss is among the lowest losses reported in literature. We also report the development of Ge-on-SOI strip waveguides for mid-infrared wavelengths centered at 3.7 μm. Minimum propagation loss of ∼8 dB/cm has been measured which commensurate with that required for high power mid-infrared sensing. Ge-on-SOI waveguides provide an opportunity to realize monolithically integrated circuit with on-chip light source and photodetector.

We demonstrate an all-silicon-photonic coherent link, including a hybrid tunable laser with <100kHz linewidth, >45dB SMSR, and <-135dB/Hz RIN as light source for a BGA-packaged 64Gbaud coherent transceiver with direct edge-coupling to 10 mu m-MFD fiber. (C) 2018 The Authors(s)

We propose and experimentally demonstrate a novel scheme for simultaneous optical sensing of electric memory cell states. Results show that the effective sensing speed can be enhanced by 976 times with 100 nm spectrum ranges.

Summary form only given. Silicon photonics circuits are playing more and more important role in optical communication and interconnect fields [1, 2]. Many silicon CMOS technique compatible photonics integrated devices are reported [3, 4]. Most of those silicon components are based on optical waveguide. But conventional integrated optical waveguide is without memory feature. One hand, which makes us in trying to change the refractive index of the optical waveguide, must continually support energy to maintain the state of the waveguide, such as optical switch and modulators. And other hands, memory functional PIC into computer memory system, will solve van Neumann bottleneck issue.In this presentation, we propose and experimentally demonstrate two solutions. First one is a non-volatile optical waveguide structure. The schematic diagram, SEM pictures of the waveguide section are illustrated in Fig. 1. For checking the memory functionality, we made a microring resonator by memory optical waveguide. By measuring the optical spectrum, the memory properties of mantain and retention are proved. And using different pulse voltage to drive electrons will cause multi-level state in the optical spectrum. Another solution is using memristor device to control the optical waveguide property. The schematic diagram and SEM and TEM pictures are showing in Fig. 2. The SONOS as the memristor, series connect with P-N junction optical waveguide. The memristor situation determines the series current, thus change the optical waveguide states. Similarly, we fabricate a microring resonator with P-N junction waveguide. SONOS controlled current to modify the microring resonator's oscillation wavelength. From optical spectrum, we will know the SONOS status. We believe those kind of memory functionality silicon PIC should useful for green photonic circuits. In memory input/output interface, will enhance the memory cell sensing speed ~1000 times.

We present mid-IR waveguides developed in Ge-on-SOI and SOI. The minimum loss achieved for Ge-on-SOI strip waveguides is ~8 dB/cm and for SOI waveguides is ~1.4 dB/cm for TE polarized light at 3.7 μm. These waveguides demonstrate the feasibility of employing Ge-on-SOI for high power integrated sensing and SOI to achieve low-loss interconnects.

100 Gbps (4 × 25 Gbps) optical receiver (Rx) module is demonstrated using Germanium (Ge) photodetector (PD) which is fabricated through Silicon-photonics process using 750 ohm-cm of high-resistivity silicon oxide insulator (SOI) wafer. Trans-impedance amplifier (TIA) and Ge PD are packaged with chip-on-board (COB) manner on a printed circuit board (PCB). High speed PCB for the assembly of both electronic and photonic devices in COB package is precisely designed from the material selection to the device footprint layout and transmission line design. The layout on PCB is optimized using high frequency simulation tool of HFSS to minimize RF loss happening in the transmission line and electrical interconnection points of bond wires. Electrical-optical (EO) S-parameter measurement for the Ge PD shows 22 GHz of transmittance (S21) 3dB bandwidth. Photocurrents of the photodetector induced by the optical input power are analyzed for signal integrity both TIA ON and OFF states. Photocurrent changes by the misalignment of the lensed optical fiber coupled to the edge coupler of the Ge PD shows that 3dB misalignment tolerances are 5.5 µm in the longitudinal and around +/-1 µm in the lateral directions. This COB packaging technique of optical Rx module can be applied for the integration and assembly of the optical module of higher data rate of 100 Gbps and beyond.

High-speed optical module is demonstrated using silicon photonics integrated circuits (Si-PIC) by compact packaging on ceramic submount of which size is 4 mm x 21 mm x 1.1 mm. The electronic integrated circuits (EIC) such as transimpedance amplifier (TIA) for photodetector and driver IC for modulator are flip-chip bonded on the submount using 1 mil diameter of Au stud bumps. The optical transceiver is packaged through the flip-chip bonding of the packaged submount by SAC solders on the evaluation PCB on which RF signal transmission lines are precisely designed. The reliable flip-chip bonding state of the EICs and submount are verified through shear test and x-ray image. Eye diagram is demonstrated at 20 Gbps for receiver module.

We extend the short-reach dynamic range of 10-Gb/s silicon photonic receiver to long-reach by changing reverse-bias of Ge-PD to adopt to input power. PD is in CMOS SOI and the electronics is in 40nm CMOS.

We report on the development of Germanium-on-SOI waveguides for mid-infrared wavelengths. The strip waveguides have been formed in 0.85 and 2 μm thick Ge grown on SOI substrate with 220 nm thick Si overlayer. The propagation loss for various waveguide widths has been measured using the Fabry-Perot method with temperature tuning. The minimum loss of ~8 dB/cm has been achieved for 0.85 μm thick Ge core using 3.682 μm laser excitation. The transparency of these waveguides has been measured up to at least 3.82 μm.

We propose an electrically programmable, multi-level non-volatile photonics memory cell (PMC) fabricated by standard CMOS compatible processes. A micro-ring resonator (MRR) was built using the PMC to demonstrate programmable and erase functions.

Silicon photonics integrated circuits (Si-PIC) with well-established active and passive building elements are progressing towards large-scale commercialization in optical communications and high speed optical interconnects applications. However, current Si-PICs do not have memory capabilities, in particular, the non-volatile memory functionality for energy efficient data storage. Here, we propose an electrically programmable, multi-level non-volatile photonics memory cell (PMC) fabricated by standard complementary-metal-oxide-semiconductor (CMOS) compatible processes. A micro-ring resonator (MRR) was built using the PMC to optically read the memory states. Switching energy smaller than 20 pJ was achieved. Additionally, a MRR memory array was employed to demonstrate a four-bit memory read capacity. Theoretically, this can be increased up to ~400 times using a 100 nm free spectral range broadband light source. The fundamental concept of this design provides a route to eliminate the von Neumann bottleneck. The energy-efficient optical storage can complement on-chip optical interconnects for neutral networking, memory input/output interfaces and other computational intensive applications.

Conventional silicon photonic integrated circuits do not normally possess memory functions, which require on-chip power in order to maintain circuit states in tuned or field-configured switching routes. In this context, we present an electrically programmable add/drop microring resonator with a wavelength shift of 426 pm between the ON/OFF states. Electrical pulses are used to control the choice of the state. Our experimental results show a wavelength shift of 2.8 pm/ms and a light intensity variation of ~0.12 dB/ms for a fixed wavelength in the OFF state. Theoretically, our device can accommodate up to 65 states of multi-level memory functions. Such memory functions can be integrated into wavelength division mutiplexing (WDM) filters and applied to optical routers and computing architectures fulfilling large data downloading demands.

Silicon photonics will increasingly be adopted into commercial applications as the technology matures, and the demand for foundries is growing as companies search for photonic integrated chip (PIC) manufacturing support. The accessibility to foundries becomes a critical aspect for technology advancement and volume production. Foundry services for multi-project wafer (MPW) shuttles, customized process runs, and small volume production are discussed in this chapter. Results and challenges in setting up a CMOS manufacturing foundry line for silicon photonics research and development along with commercialization are also presented. The existing gap in the value chain presents an opportunity for foundries to be involved in a silicon photonics market that is primed for growth.

We report on the improvement of propagation loss in Ge-on-SOI waveguides developed for mid-infrared wavelengths. Strip waveguides of varying widths have been developed in 0.85 μm thick Ge core and an improvement of up to ~3.5 dB/cm has been achieved by annealing the samples at 700 °C for 120 s. The improvement is consistent for both TE and TM polarized light at 3.682 μm. The method is proven feasible for repairing material growth defects and achieving loss performance commensurate with that required for integrated photonics for sensing applications. The minimum propagation loss achieved is ~10 dB/cm after annealing.

An ultra-simple polarization rotator is demonstrated on SOI platform with self-aligned process to enhance performance repeatability and manufactural yield. The polarization rotation is essentially achieved by the symmetry breaking of a channel waveguide with a single-sided slab. The two-step lithography enabling this structure is fully compatible with the mainstream process flow of Si photonic integration. A polarization conversion efficiency of 93% is obtained at 1560nm in less than 10μm light propagation length. The merit of flat-band operation (> 100nm) by using asymmetric waveguide for polarization rotation is inherited.