The demand for a high capacity optical communication network with low power consumption is increasing with the expanding use of the internet and mobile technology.
We have pursued ultimate performance by utilizing various materials, and creating a new optical device technology that enables various network formats.
We have been working on research using silica PLC technology, optical semiconductor technology and heterogeneous integration technology which combines silica and semiconductor devices, focusing mainly on optical components, modules and materials to support future communication networks.
Slica-based planar lightwave circuit (PLC) devices
Planar lightwave circuits (PLC) are based on both optical fiber and LSI fabrication and waveguide design technologies for optical signal processing. High performance compact PLCs integrated with optical functions have excellent features of low loss, high reliability, high throughput and design flexibility.
Optical semiconductor device
Optical semiconductor devices include high-performance semiconductor lasers, high-speed tunable light sources and small optical modulators, made of compound materials such as InP. With a view to realizing high-speed semiconductor devices with a low power consumption, we have been undertaking research in relation to, for example, epitaxial growth, fine processing technology and packaging technology, by taking advantage of the high emission efficiency of compound semiconductors.
Heterogeneous and hybrid integrated devices
Heterogeneous and hybrid integration technologies are promising approaches to realize functional integrated devices. High performance optical devices such as wavelength filters and light sources are made of suitable materials for their functions. These integration technologies can utilize various materials such as silica and compound semiconductors, and realize various integrated devices appropriate for the target functions.
AWG (Silica-based PLC)
An arrayed waveguide grating (AWG) is an optical wavelength filter device that splits and combines optical signals by wavelength. Wavelength division multiplexing (WDM) systems around the world employ AWGs because they have excellent optical performance including high wavelength resolution. AWGs remain key devices in large capacity optical networks.
DFB laser array integrated with EA modulator
A DFB laser array integrated with an EA modulator is a light source for short distance optical networks called metro-access regional networks. The light output from each semiconductor laser is modulated into a high-speed optical signal with an EA modulator. Then, high capacity data can be transmitted by multiplexing to the optical signals from each channel. Furthermore, the DFB laser array can contribute to the realization of an environmentally friendly optical network due to its wide temperature range characteristics and low power consumption operation.
Heterogeneous integrated PLC based coherent receiver
A coherent receiver is an essential device for high-speed optical networks with data rates of 100/400-Gb/s or more. The integration of InP-based high-speed photodetectors, silica-based precise interferometers and silica-based polarization beam splitters can provide more functional receivers. We employed the heterogeneous integration of silica PLCs and InP-PDs, and demonstrated a compact integrated coherent receiver with low loss and high performance.