Integrated optical sensor utilising a 1D CCD array for multiple output addressing

An inexpensive and robust method for acquiring multiple outputs from integrated optical sensor devices using a 1D CCD array is described in this paper. An example is given of the development of an instrument based on the use of an integrated optical Mach-Zehnder interferometer (MZI) refractive index transducer. The technique is especially promising for application to multianalyte sensors where several outputs need to be interrogated simultaneously. The high sensitivity and low noise demonstrated by the system will enable the use of cheap, stable LED light sources in practical instruments. Introduction: Integrated optical transducers for the real-time measurement of interactions between biological molecules and for the specific detection of chemical and biochemical species are the subject of growing interest. Applications of this technology include environmental pollution monitoring, industrial process control and medical diagnostics. Integrated optical sensors provide the high detection sensitivity achievable using optical transduction techniques in a compact and robust format. This approach also offers advantages for the fabrication of multianalyte sensors through the integration of multiple transducers on a single chip by straightforward scaling of the photolithographic production process. Several types of integrated optical sensor have been described (e.g. [1-3]), but no commercially viable multianalyte system currently exists and, in order to fully exploit this technology in practical instrumentation, inexpensive and reliable techniques for addressing the multiple outputs of waveguide devices must be found. Fibre-to-chip pigtailing of integrated optical devices formed in 'passive' materials such as glass, where it is difficult to truly integrate monolithic light sources and detectors, is not the best solution when dealing with multiple outputs due to the necessity of producing and pigtailing fibre arrays. For single input devices, however, fibre input coupling is still a viable option as only a single pigtail needs to be made. In this paper we present measurements on multiple-output integrated optical sensor devices using fibre input coupling and a cheap, readily available, 1D CCD array detector to simultaneously address all outputs. A lens is used to focus the waveguide outputs onto the array, resulting in a compact unit that can be housed in a standard instrument package. A further advantage of this arrangement is that other optical elements such as filters and polarisers can readily be inserted into the beam path