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A study on asymmetric integrated optical Y-branches proposes the use of single-mode asymmetric Y-branches using microprisms to enhance their performance as compared to conventional single-mode asymmetric Y-branches. The configuration of the suggested asymmetric Y-branch, 3-dB power divider is presented. Applications of asymmetric Y-branches in integrated optical circuits will be of great interest in the near future. Experimental results are presented.

A useful design rule for the low-index prism structure was obtained by the concept of phase matching. The designed low-index prism bends were observed to have low-loss and large-angle properties similar to high-index prism bends. Field distortion caused by the prism is discussed as well as the influences of prism length, width and index on the propagation loss. A comparison of the field distribution and design rule of the high-and low-index prism bends was performed.

The use of micro-prisms to improve the design of three-dimensional bends of step-index waveguides is considered. The approach, which applies to both embedded and buried waveguides, includes a micro-prism design rule to address phase mismatch which leads to bending loss. According to a simulation carried out by the finite-difference beam propagation method, the improved bends achieve dramatic gains in their transmission capabilities.

A newly developed large-angle low-loss direction-coupler type power divider has a designed ratio between output waveguides and employs a micro-prism at the bend corner to restrict radiation loss, compensating for phase mismatch due to bending. The semivectorial beam propagation method simulates a 93% normalized transmitted power of the power divider with a bend angle of 10 degrees. Less than 0.953 dB loss is calculated for a symmetric large-angle 3-dB directional coupler with eight microprisms.

A new low-loss abrupt bend structure for optical waveguide utilizes a microprism to compensate for the phase front phase difference after and before the bend corner. The compensation helps align the phase front of the eigenmode properly. Simulations indicate a 95% normalized transmitter power at 10 degrees of bend angle. A phase compensation rule and its corrections help derive the optical parameters of the prism.