Silicon-based high-resolution and low-power-consumption two-dimensional beam scanner integrated with hybrid wavelength-tunable laser diode.

Optical phased array (OPA) is a useful device for achieving the solid-state beam scanner required in compact light detection and ranging. However, conventional OPAs actively control the phase difference between arrays. Therefore, power consumption is extremely high in a high-resolution OPA. Herein, we fabricated a passive OPA with a 128-channel silicon arrayed waveguide and Si-dot grating antennas with large apertures. Moreover, we integrated a hybrid wavelength-tunable laser diode with a passive OPA. The field of view was 43.9° × 10.4°, and the FWHM of the beam width was 0.233° × 0.0495°. The power consumption per antenna was 0.397 mW.

Hybrid laser diode with ultrawide wavelength-tunable range using curved directional couplers.

Wavelength-tunable laser diode with a wide tuning range is required for optical communication systems and optical sensing. External cavity laser diodes with silicon-photonic wire waveguides and ring resonators have small footprint because of high refractive index contrast between Si. However, power coupling efficiency κ of conventional straight directional coupler between ring and bus waveguides have large wavelength dependence, which lowers tunable range. In this study, we demonstrate a hybrid wavelength-tunable laser diode using curved directional couplers, whose wavelength dependence on κ is low. The wavelength-tunable range record of 120.9 nm has been achieved. In addition, curved directional couplers are tolerant of waveguide width fabrication error.

Camera sensor platform for high speed video data transmission using a wideband electro-optic polymer modulator.

In this work, 1 GHz video data was collected by a CMOS camera and successfully transmitted by the electro-optic (EO) modulator driven by an external modulation module integrated onto the same chip. For this application, the EO modulator component included a polymer waveguide modulator, which performed a 20 GHz bandwidth, clear eye diagram opening with a Q factor of 10.3 at 32 Gbit/s and a drive voltage of 1.5 Vpp. By utilizing a thermally stable EO polymer, the wide-band polymer modular can yield a photonic integrated camera sensor system which is a reliable processing platform for real-time data processing.

Compact thermo-optic MZI switch in silicon-on-insulator using direct carrier injection.

In this paper we present a compact direct current injection thermo-optic switch based on a Mach-Zehnder Interferometer configuration that is suitable for autonomous vehicle applications as it has a low heating resistance value of 97 Ω, a rapid 2.16 µs switching time constant, and a Pπ of 28 mW. The device relies on multimode interference to achieve low optical insertion losses of less than 1.1 dB per device, while allowing direct current injection to heat the waveguide and achieve fast operation speeds. Furthermore, the total resistive value can be tailored as the heating elements are placed in parallel.

Narrow-spectral-linewidth silicon photonic wavelength-tunable laser with highly asymmetric Mach-Zehnder interferometer.

We propose a narrow-spectral-linewidth silicon photonic wavelength-tunable laser with a novel external wavelength-tunable filter, which consists of two silicon ring resonators with different circumferences and a highly asymmetric Mach-Zehnder interferometer (MZI), the two optical paths of which have significantly different lengths. Calculations and experimental results indicated that the gain difference between longitudinal modes was increased by the highly asymmetric MZI. Consequently, a narrow spectral linewidth of 12 kHz and a stable single-mode oscillation were obtained.