Abstract— Optical filters are a fundamental part of spectrometric measurements of ultraviolet (UV), visible and infrared (IR) radiation. In the present paper, optical filter is considered as a part of an optical system that has the purpose of modifying the intensity, polarization or, in particular, the spectral distribution of light. A beam of light enters through an aperture, is modified, and ...

The optimization of multiplexing (MUX) and demultiplexing (DMUX) 3-dB filter bandwidths for the optical differential quadrature phase shift key (DQPSK) combined with the return-to-zero (RZ) and carrier-suppressed returnto-zero (CS-RZ) is performed. The study of different optical signals in the 40 Gb/s dense wavelength division multiplexing (DWDM) system, with high spectral efficiency, is shown ...

We report ultra-compact surface-normal high-Q optical filters based on single- and double-layer stacked Fano resonance photonic crystal slabs on both Si and quartz substrates. A single layer photonic crystal filter was designed and a Q factor of 1,737 was obtained with 23 dB extinction ratio. With stacked double-layer photonic crystal configuration, the optical filter Q can increase to over 10,...

Optical Doppler tomography is a valuable functional extension of optical coherence tomography (OCT) that can be used to study subsurface blood flows of biological tissues. We propose a novel frequency estimation technique that uses an adaptive notch filter (ANF) to track the depth-resolved Doppler frequency. This new technique is a minimal-parameter filter and works in the time domain without t...

The development of tunable filters is a key point for the ability of optical telecommunication networks to comply with the continuous evolution of the service providers needs. Among the numerous technologies which can be used to achieve narrow bandpass filtering devices, we concentrate our analysis on Thin-Film Interference Coatings and compare the principles, performances and use constraints o...

The phase-only logarithmic radial harmonic (LRH) filter has been shown to be suitable for scale-invariant block object recognition. However, an important set of objects is the collection of contour functions that results from a digital edge extraction of the original block objects. These contour functions have a constant width that is independent of the scale of the original object. Therefore, ...

Microwave photonic filters (MPFs) are of great interest in radio frequency systems since they provide prominent flexibility on microwave signal processing. Although filter reconfigurability and tunability have been demonstrated repeatedly, it is still difficult to control the filter shape with very high precision. Thus the MPF application is basically limited to signal selection. Here we presen...

We optimize the design of a short-range communication system using nondirected line-of-sight IR radiation. We propose a receiver structure comprising a spherical thin-film optical filter and a truncated spherical lens that can significantly outperform an optimized planar-filter system. We can make the passband of the spherical filter arbitrarily narrow without constraining the field of view by ...

We have demonstrated the Šolc-type wavelength filters in a 52mm long periodically poled Ti diffused lithium niobate channel waveguide which has a domain period of 16.6μm. At room temperature, the center wavelength and the full-width at half maximum of the filter were about 1272.49nm and 0.23nm, respectively. The nearest side-lobe is about 7dB. New structure of optical add/drop multiplexer (OADM...

We present results of a correlation filter utilising a computer generated hologram using an analogue ferroelectric liquid crystal spatial light modulator (SLM). The SLM amplitude modulates light and can induce a 0/π phase shift, which is equivalent to modulating along the real axis. Two pixels are combined into a macropixel using a phase detour technique enabling full complex modulation. The me...