Abstract: A tuneable laser is disclosed, including a gain section with first and second comb reflectors to one side thereof. The two reflectors each provide combs with substantially uniform spacings, the spacings differing as between the combs. Each comb reflector can be tuned so as to shift the reflective peaks of the combs, thus allowing alignment of a single reflective peak at a chosen wavelength which is the same in both combs, forming a supermode. This supermode has an intensity greater than the threshold of the gain section and thus the laser produces an output at that selected wavelength.

Abstract: A tuneable laser is disclosed, including a gain section with first and second comb reflectors to one side thereof. The two reflectors each provide combs with substantially uniform spacings, the spacings differing as between the combs. Each comb reflector can be tuned so as to shift the reflective peaks of the combs, thus allowing alignment of a single reflective peak at a chosen wavelength which is the same in both combs, forming a supermode. This supermode has an intensity greater than the threshold of the gain section and thus the laser produces an output at that selected wavelength.

Abstract: The array is highly suitable for producing a spacially wide output “beam” (comprising a number of individual beams). It suffers less from problems of hotspots and filamentation since each tapered laser supports a limited number of modes, or even a single mode. Therefore it produces a semiconductor laser which is especially suitable for pumping of other lasers and to be used in materials processing.

Abstract: A reverse osmosis membrane having a support which itself has properties of salt rejection laminated to a layer of a cross-linked polyol. The support is a sulphonated aromatic polyether sulphone, and the polyol ma be polyvinyl alcohol.