Spatial Planar Optical Circuit-Innovative photonic circuit technology bringing out advantages of planar optical waveguides and free-space-optics-

Optoelectronics Integration Research Group

Technology

Increasing telecom traffic has created a great demand for photonic devices with large capacity, small footprint, and high functionality. Novel technologies to manipulate lightwaves more flexibly are highly desired in order to meet this demand. A spatial planar optical circuit (SPOC) is an innovative optical platform that integrates free space optics (FSO) with optical waveguides. This platform brings out the advantages of both the optical waveguides and FSO. We are trying to overcome the limitations of conventional photonic devices by using the SPOC platform (Fig. 1).

Fig.1: Applications of SPOC.
Fig.1: Applications of SPOC.

Features

Generally, waveguides can be densely integrated in an optical circuit on the two-dimensional plane. On the other hand, FSO can parallelize an optical circuit in three-dimensional space on a massive scale. Figure 2 shows a schematic of the SPOC platform. The SPOC technique combines the advantages of both the waveguide and FSO, which enables us to realize high-performance optical devices. In addition, the optical functions of SPOCs can be reconfigured flexibly by controlling the optical wavefront with a spatial light modulator (SLM).

Fig.2: Schematic of SPOC platform.
Fig.2: Schematic of SPOC platform.

Application

In our research group, we apply the SPOC technique to photonic node devices. The large capacity and high degree of integration of SPOCs allow us to develop photonic node devices with ultra-high-capacity, which is several hundred times larger than that of waveguide-based ones. In addition, the functions of SPOC-based node device can be dynamically reconfigured by utilizing their high flexibility and variable functionality (Fig. 3). We contribute to advancing the ICT infrastructure to make the most of big-data technology by realizing ultra-high-capacity photonic networks.

Fig.3: Schematics of SPOC-based photonic nodes and examples of their applications.
Fig.3: Schematics of SPOC-based photonic nodes and examples of their applications.

Abbreviation

SPOC Spatial planar optical circuit
FSO Free space optics
ICT Information and communications technology
SLM Spatial light modulator
WSS Wavelength selective switches
FPGA Field-programmable gate array

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