title: Condition for the realization of a temperature-insensitive long-period waveguide grating.
abstract: We analyze the condition for achieving a temperature-insensitive resonance wavelength of a long-period grating formed in a channel waveguide. We find that by controlling the waveguide cladding thickness, zero temperature sensitivity can be achieved with core and cladding materials that have significantly different thermo-optic coefficients. To verify our finding, we design a polymer long-period waveguide grating (LPWG) according to the zero-sensitivity condition, where the thermo-optic coefficient of the core is twice that of the cladding. The temperature sensitivity of the fabricated grating is within +/-0.15 nm/ degrees C over a temperature range of approximately 15 degrees C, which is more than an order of magnitude lower than those of previously reported LPWGs fabricated with the same materials.
authors.affiliation: Department of Electronic Engineering, City University of Hong Kong, China. qingliu@cityu.edu.hk
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.forename: Kin Seng
authors.initials: KS
authors.lastname: Chiang
authors.forename: Kar Pong
authors.initials: KP
authors.lastname: Lor