Compact three-port optical circulator of W-format

We show in this work a possibility of design a more compact three-port optical circulator wiht W-format as compared to the known one with Y-format. The W-circulator is more compact, but it does not have the rotational symmetry of the Y-circulator. As consequence the minimum of isolation and maximum of transmission responses are not more coincident in frequency, as is shown by the presented simulation results. However the frequency shift is not critical.