Divide and conquer: an efficient solution to highly multimoded photonic lanterns from multicore fibres.

Photonic lanterns typically allow for single-mode action in a multimode fibre. Since their invention over a decade ago for applications in astrophotonics, they have found important uses in diverse fields of applied science. To date, large aperture highly-mulitmoded to single-mode lanterns have been difficult as fabrication techniques are not practical for mass replication. Here as a proof of concept, we demonstrate three different devices based on multicore fibre photonic lanterns with: 100µm core diameters; NAs = 0.16 and 0.15; and requiring 259 single-mode core system, specifically 7 multicore fibres each with 37 cores, instead of 259 individual single-mode fibres. The average insertion loss excluding coupling efficiencies is only 0.4dB (>91% transmission). This concept has numerous advantages, in particular, (i) it is a direct scaleable solution, (ii) eases imprinting of photonic functions, e.g. fibre Bragg gratings; and (iii) new approach for large-area optical fibre slicers for future large-aperture telescopes.

Long period grating in multicore optical fiber: an ultra-sensitive vector bending sensor for low curvatures.

Long period grating was UV inscribed into a multicore fiber consisting of 120 single mode cores. The multicore fiber that hosts the grating was fusion spliced into a single mode fiber at both ends. The splice creates a taper transition between the two types of fiber that produces a nonadiabatic mode evolution; this results in the illumination of all the modes in the multicore fiber. The spectral characteristics of this fiber device as a function of curvature were investigated. The device yielded a significant spectral sensitivity as high as 1.23 nm/m(-1) and 3.57 dB/m(-1) to the ultra-low curvature values from 0 to 1 m(-1). This fiber device can also distinguish the orientation of curvature experienced by the fiber as the long period grating attenuation bands producing either a blue or red wavelength shift. The finite element method (FEM) model was used to investigate the modal behavior in multicore fiber and to predict the phase-matching curves of the long period grating inscribed into multicore fiber.

Hexabundles: imaging fiber arrays for low-light astronomical applications.

We demonstrate a novel imaging fiber bundle ("hexabundle") that is suitable for low-light applications in astronomy. The most successful survey instruments at optical-infrared wavelengths use hundreds to thousands of multimode fibers fed to one or more spectrographs. Since most celestial sources are spatially extended on the celestial sphere, a hexabundle provides spectroscopic information at many distinct locations across the source. We discuss two varieties of hexabundles: (i) lightly fused, closely packed, circular cores; (ii) heavily fused non-circular cores with higher fill fractions. In both cases, we find the important result that the cladding can be reduced to ~2 µm over the short fuse length, well below the conventional ~10λ thickness employed more generally, with a consequent gain in fill factor. Over the coming decade, it is to be expected that fiber-based instruments will be upgraded with hexabundles in order to increase the spatial multiplex capability by two or more orders of magnitude.

The use of carers' and users' expectations of services (CUES) in an epidemiological survey of need.

BACKGROUND AND METHOD: This study surveyed need in a group of psychiatric patients in Gloucester, using a new instrument, the CUES. Keyworkers gave out questionnaires to all patients with psychosis in contact with specialist services. A total of 148 forms were anonymously completed, with a response rate of 37% of the mental health services caseload. RESULTS: 53.5 to 83.2% of patients were satisfied and 61.5 to 89.6% expressed their experiences 'as good as' a normative statement across the 16 domains. There was mostly 'moderate' agreement between satisfaction and normative questions by Kappa correlations, although responses to normative questions tended to be about 10% higher. Extensive free text responses were subject to content analysis, demonstrating needs across a wide range of health, social and leisure areas, many of which were not directly linked to the adequacy or otherwise of psychiatric treatment. CONCLUSIONS: The results imply that the CUES may be of value at an individual level to aid in care planning, and also have some value in aggregated form to benchmark user experiences of services.

From research to practice: a local mental health services needs assessment.

BACKGROUND: Service planning based on aggregated needs assessment is rarely practised. There is a lack of research into how population-based needs assessment approaches can be translated into routine clinical settings. AIMS: This study aimed to ascertain the 2-month period prevalence of psychosis in Gloucester City, to investigate the level of need among those in contact with mental health services, and to identify the compromises which are involved in routine collection of data to inform services, compared with specifically funded research studies. Method People with ICD-10 diagnosis of functional psychosis were identified by searching General Practice and mental health service records in Gloucester City. The needs of the sub-sample in touch with mental health services were assessed using the Camberwell Assessment of Need Short Appraisal Schedule (CANSAS). RESULTS: Four hundred and seventy-four cases were identified, including 403 in contact with mental health services. Staff CANSAS data were collected for 225 patients, with a mean rating of 7.0 met and 3.6 unmet needs per patient. Unmet need was higher in the non-Caucasian group. CONCLUSIONS: In this locality, patients with functional psychosis were largely in contact with mental health services, were in employment, were disproportionately looked after by a few City centre General Practitioners, and high levels were in supported accommodation. Higher levels of need were found than previously demonstrated. Systematic assessment of needs with research instruments to contribute to locality service planning is possible without a major research grant, but involves compromises on established research designs.