1x7 plastic optical fiber coupler using cylindrical mixing rod

A novel low-cost 1x7 plastic optical fiber coupler using cylindrical mixing-rod is proposed. Comparing with conventional tapered mixing-rod plastic optical fiber 1x7 coupler, the proposed coupler, which uses cylindrical POF as mixing-rod instead of tapered POF in order to save the high demanding POF tapering process, is much lower at cost and only a little deteriorate at crosstalk. The increased crosstalk and its power penalty are theoretically calculated showing that crosstalk lower than 20dB results in insignificant power penalty. The coupler was experimentally tested showing an excess loss of less than 2.5dB and uniformity less than 3.56dB.