Mode Synthesis in Photonic Bandgap Fibers

We report the successful synthesis of three individual modes, HE11, TE01, and TE02 for transmission in photonic band gap fibers at near infrared wavelengths. We measure the propagation losses of the HE11 and TE01 modes both inside and outside the band gap of the fiber, show that the TE01 is indeed the lowest loss mode, and is less lossy and has a much wider band gap than the HE11. We study the superpostions of the HE11 and TE01 modes using the pure phase approach, and discuss the degeneracy problem that arises. We analyze these superpositions by decomposing the superposed images into low energy eigenmodes (m < 3), and compute each of the eigenmode''s contribution in the linear superposition. We show that the contributions of the HE11 and TE01 behave sinusoidally in their superpostions.