The temperature dependence of polarization-maintaining (PM) property and loss in a highly-birefringent air-core photonic band-gap fiber (PBF) is investigated.

The PM property of this PBF is insensitive to the temperature, and the temperature-dependent beat-length coefficient can be as low as 2.86×10⁻⁸ m/°C, the PBF has a stable confinement loss of 0.01 dB/m over the temperature range of −30 to 20 °C for the slow axis at the wavelength of 1.55 μm.

It is found that the dominant mechanisms that contribute the temperature dependence of beat-length and confinement loss are the thermo-optic effect in the waveguide material and thermal expansion of the silica, respectively.