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A GaN/sapphire 1 × 4 Optical Power Splitter Using Five Rectangular Waveguide for Underwater Application*

This work reports a design of a simple four-branch optical power splitter using five parallel rectangular waveguides in GaN/sapphire for underwater application. The proposed power splitter works according to coupled mode phenomena occurred between the adjacent waveguides. The numerical experiments were carried out using the FD-BPM method to obtain a four uniform optical power output. The simulation conducted at the input wavelength of 0.45 μm for TE polarisation. The result shows that at propagation length of 770 μm, the optical power is successfully split into four output beams with an excess loss of 0.41 dB and imbalance of 0.1 dB.