Use of Cross-Couplers to Decrease Size of UV Written Photonic Circuits

We demonstrate compact cross-couplers for fiber-pigtailed photonic circuitry produced by direct ultraviolet writing. A new design solution has been applied to shorten the device in length by 400% while keeping the bend loss at a level of <0.1 dB, which allows the use of cross-couplers in more complex photonic circuits with a smaller footprint and propagation loss. We demonstrate symmetrical cross-coupler operation and device performance that surpasses that of previously reported cross-couplers in terms of balanced symmetry and minimized footprint.