Analysis of four patterns of photonic crystal fibers with ultrahigh birefrigence

A High birefringence and low confinement loss of three patterns photonic crystal fibers (PCFs) are investigated and compared by using finite element method. Results show that the mode birefringence of proposed PCF with rectangular air holes at λ= 1.55 μm reaches 8.1 × 10-2 (which is the highest value to our knowledge) and the confinement loss is less than 5×10-3 dB/km, respectively. Besides, an ultrahigh birefringence up to 2.76 × 10-2 is also achieved from the proposed circular air holes PCF, which is the highest value compared to conventional circular air holes PCF.