Temperature-independent strain sensing characteristics of coupled photonic crystal waveguides

• A highly sensitive strain sensor based on coupled two-dimensional (2D) photonic crystal waveguides consisting of dielectric rods array immersed in air is designed. The effective side-coupling between directional coupled waveguides and surrounding defect cavities gives flexibility in the choice of the sensing monitoring band.
• Dual-channel sensing method is proposed to eliminate the cross sensitivity effect between the strain and ambient temperature, and render a new category of temperature-independent strain sensing devices.
• The combination of PC structure and sensing technology by using silicon cantilever embedded with a two-dimensional photonic crystal structure can be suitable in constructing integrated optoelectronic systems applied to other sensing fields.

A highly sensitive strain sensor based on coupled two-dimensional (2D) photonic crystal waveguides consisting of dielectric rods array immersed in air is designed. The effective side-coupling between directional coupled waveguides and surrounding defect cavities gives flexibility in the choice of the sensing monitoring band. The coupling process and transmission spectral properties are analyzed by the finite difference time domain (FDTD) method. The influence of strain and temperature on the transmission spectrum is investigated by monitoring the wavelength shift in the loss peaks. The dual-channel sensing method is proposed to eliminate the cross sensitivity effect between the strain and ambient temperature, and render a new category of temperature-independent strain sensing devices.