The present invention provides an optical delay, for example, an optical delay line, having at least first and second waveguides, each waveguide having a first end at a first side of the device and a second end at a second side of the device, wherein the second end of the first waveguide is coupled to the second end of the second waveguide at a reflective coupling region, which reverts the direction of propagation of radiation in the device from propagating towards the second side of the device via the first waveguide to propagating towards the first side of the device via the second waveguide.