All fiber wavelength and mode selective coupler for optical inter-connections

A new wavelength and mode selective coupler (WMSC) was fabricated coupling hollow optical fiber and standard single mode fiber. This compact and robust wavelength and mode selective coupling device(WMSC) has a broad band of operation, low insertion loss, and high mode conversion efficiency. The fabricated WMSC routes 1.3 μm signals directed to the holey optical fibre (HOF) port converting LP₀₁ mode to a ring shape mode and transports 1.5 μm signal to the SMF port in LP₀₁ mode. The measured insertion loss at 1.3 μm and 1.5 μm were 2.1 dB and 0.15 dB, respectively. The channel isolations at 1.3 μm was over 9.8 dB and 1.5 μm was over 20 dB. The coupling efficiency from LP, mode of SMF to the ring shape mode of HOF around 13 μm was ∼88% and the coupling efficiency from the LP₀₁ mode of SMF to the LP₀₁ mode of SMF around 1.5 μm was ∼97%. The proposed device can be used for applications in all optical inter-connections among fiber links.