A zero-optical-path-length-difference optical phased array built with essentially planar photonic devices determines a direction to an incoherent optical source, such as a star. The phased array can replace a 3-dimensional star tracker with a nearly 2-dimensional system that is smaller and lighter. The zero-optical-path-length-difference phased array can be optically connected to an interferometer. Driven by a light source, the zero-optical-path-length-difference phased array can be used as an optical projector.

A zero-optical-path-length-difference optical phased array built with essentially planar photonic devices determines a direction to an incoherent optical source, such as a star. The phased array can replace a 3-dimensional star tracker with a nearly 2-dimensional system that is smaller and lighter. The zero-optical-path-length-difference phased array can be optically connected to an interferometer. Driven by a light source, the zero-optical-path-length-difference phased array can be used as an optical projector.

Aspects and embodiments are generally directed to optical systems, receivers, and methods. In one example, an optical receiver includes a plurality of fused fiber optic bundles, at least a first fused fiber optic bundle of the plurality of fused fiber optic bundles positioned to collect optical radiation from a scene, a multi-mode fiber optic cable coupled to each fused fiber optic bundle of the plurality of fused fiber optic bundles, the multi-mode fiber optic cable configured to propagate the collected optical radiation from each of the plurality of fused fiber optic bundles along a length of the multi-mode fiber optic cable, and a photo-detector coupled to the multi-mode fiber optic cable and configured to receive the collected optical radiation. A field of view of each fused fiber optic bundle of the plurality of fused fiber optic bundles may collectively define a substantially omnidirectional field of view of the photo-detector.

A photonic crystal all-optical D-type flip-flop includes an optical switch unit, a photonic crystal structure unit including two signal-input ends, a signal-output end and an idle port, a wave absorbing load and a reference-light source; the clock signal-input port of the photonic crystal structure unit is connected with a clock control signal; a second port of the photonic crystal structure unit is an intermediate signal-input port, said intermediate signal-input end of the photonic crystal structure unit is connected with a first intermediate signal-output end of the optical selector switch; a logic signal is connected with the first signal-input end of the optical switch unit; the absorbing load is connected with a second intermediate signal-output end of the optical switch unit; said reference-light source is connected with a second signal-input end of the optical switch unit, which is a reference-light input end connecting with the output end of said reference-light source.

The present invention provides a switch device for an optical signal which has high extendibility and which can suppress an increase of loss in extension. A switch device in one embodiment of the present invention includes, in a housing, four splitter portions, four switch portions, and extension splitter portions. The splitter portions are connected to path-side ports, the switch portions are connected to client-side ports, and the splitter portions and the switch portions are connected to one another via shuffle fiber arrays. One ends of the extension splitter portions are connected to path-side extension ports, and the other ends thereof are connected to client-side extension ports. The number of wavelengths processable by the switch device can be easily changed by changing a connection state of optical fibers to the path-side ports, the client-side ports, the path-side extension ports, and the client-side extension ports.