We demonstrate a 1×2 wavelength-division multiplexing switch for few-mode fiber based on a spatial light modulator. We measure its crosstalk, frequency roll-off, mode dependence and other transmission characteristics. Introduction In response to saturating capacity achievable in single-mode fiber, space-division multiplexing (SDM) has become an established research area. Parallelization and com...

Selective laser melting (SLM) is widely used in making three-dimensional functional parts layer by layer. Temperature magnitude and history during SLM directly determine the molten pool dimensions and surface integrity. However, due to the transient nature and small size of the molten pool, the temperature gradient and the molten pool size are very challenging to measure and control. A 3-dimens...

The high peak-to-average power ratio of the transmit signal is a serious drawback of multicarrier transmission. To cope with this problem, peak power reduction schemes have been developed. One popular method is selected mapping (SLM), where several alternative representations are generated from the information carrying signal and that one which exhibits the lowest peak power is selected for tra...

The speed of most parallel-aligned liquid-crystal-on-silicon (LCoS) spatial light modulators (SLMs) is limited to the video rate of their drivers, which is a limitation for high-speed applications. However, the LCoS SLM presented here has a driver allowing a frequency range of up to 1011 Hz. Using the static phase modulation characterization and the static lookup table (LUT), the phase modulati...

High Peak-to-Average Power Ratio (PAPR) is the one of the major drawback of the Orthogonal Frequency Division Multiplexing (OFDM) transmitted signal. Thus, a high-dynamic range amplifier is needed, which increases the cost of the system. In this paper, a new PAPR reduction technique using new phase sequence based on some existing scheme is proposed to reduce the high Peak-to-Average Power Ratio...

Used as a wavefront corrector, a liquid crystal spatial modulator (LC-SLM) has good repeatability and linearity, which are essential for open-loop adaptive optics, and the open-loop optical system can increase the light energy efficiency by a factor of two for the LC-SLM and improve the system bandwidth. In order to test the performance of the LC-SLM in open-loop correction, an indoor closed-lo...

We propose a novel optical method to display a complex Fresnel hologram using a single spatial light modulator (SLM). The method consists of a standard coherent image processing system with a sinusoidal grating at the Fourier plane. Two or three position-shifted amplitude holograms displayed at the input plane of the processing system can be coupled via the grating and will be precisely overlap...

John T. Sheridan, MEMBER SPIE University College, Dublin College of Engineering, Mathematics and Physical Sciences School of Electrical, Electronic and Mechanical Engineering and Optoelectronic Research Centre and SFI-Strategic Research Cluster in Solar Energy Conversion Belfield, Dublin 4, Ireland E-mail: [email protected] Abstract. An optical implementation of the amplitude encoded double ...

This paper describes the nyquist filter based technique to reduce the peak to average power ratio (PAPR) in multiple input multiple output Orthogonal Frequency Division Multiplication (MIMO-OFDM) systems. OFDM-MIMO system faces one of the main problems regarding PAPR of a transmitted signal. In present paper a nyquist filter along with conventional selected mapping (SLM) and alternative multise...