Jun-Won An

Effects of apodization on a holographic demultiplexer based on a photopolymer grating

An investigation of the effects of apodization on a holographic demultiplexer that is based on a photopolymer grating is presented. Uniform and Gaussian apodized gratings are fabricated in a DuPont HRF-150-38 photopolymer. From the theoretical and experimental results, the spectral response of the apodized grating has a larger main lobe but lower sidelobes than those in the uniform-grating case. A 42-channel demultiplexer that is based on the Gaussian apodized grating with an 0.4-nm channel spacing is demonstrated. A cross-talk level of -30 dB and an interchannel uniformity of 1.5 dB are archived in the wavelength range of approximately 1550 nm.

Volume holographic wavelength demultiplexer based on rotation multiplexing in the 90° geometry

Abstract A novel photorefractive wavelength demultiplexing scheme for optical communications and spectroscopy applications has been proposed and experimentally demonstrated for the first time, by using the narrowband filtering and demultiplexing properties of volume holographic gratings formed in LiNbO 3 :Fe crystal. The holographic gratings are superimposed in the crystal with rotation multiplexing in the 90° geometry. In this scheme, the center wavelength and orientation of the grating for each channel are simply changed by rotating the crystal with respect to the crystal axis without changing the recording angles. To verify the proposed scheme we have designed the 16-channel demultiplexer with a 3 dB spectral bandwidth of 0.16 nm and a channel spacing of 0.5 nm in the wavelength region of around 670 nm. Some preliminary experimental results are presented and discussed.

50 GHz-Spaced 42-Channel Demultiplexer Based on the Photopolymer Volume Grating.

A 42-channel demultiplexer based on the photopolymer volume grating is experimentally demonstrated. A channel uniformity of 1.6 dB, 3 dB bandwidth of 0.18 nm, and channel crosstalk of -20 dB for a 50 GHz channel spacing, are achieved.

Gaussian Apodization Technique in Holographic Demultiplexer Based on Photopolymer

In this paper, a Gaussian apodization technique applied to a transmission volume hologram for holographic demultiplexer is proposed. The Gaussian apodized grating of 15 mm

A Hybrid Algorithm to Reduce the Computation Time of Genetic Algorithm for Designing Binary Phase Holograms

{\times}

Beam steering device using CGHs

11mm size,

Computer generated hologram for phase-only optical encryption

38{\mu}m

Hybrid algorithm to reduce the computation time of genetic algorithm for designing binary phase holograms

thickness and 3.2 mm horizontal standard deviation of the Gaussian index modulation profile was fabricated. A 22-channel demultiplexer based on that grating has been optically demonstrated. The channel spacing, the interchannel cross-talk level and the channel uniformity of 0.8 nm, -30 dB and 1.5 dB, respectively, were obtained.

Improved genetic algorithm for optimization of binary phase holograms

A new approach to design binary phase holograms, with less computation time and equal effi-ciency compared with the genetic algorithm method, is proposed. Synthesized holograms having diffraction efficiency of 75.8% and uniformity of 5.8% are tested in computer simulation and experimentally demonstrated.

Gaussian apodization technique in a holographic demultiplexer based on photopolymer

A new beam steering scheme using computer-generated holograms(CGHs) is proposed. The steering devices in order to control the reference and object wave are necessary in various holographic multiplexing methods. The beam steering device using CGHs can be simultaneously processed the coarse address function controlling the beam up or down so as to select slice and the fine address function adjusting to the particular holographic page within the chosen layer. From the experimental results, we show that the beam steering can be easily implemented and so powerful to generate the electrically addressed reference wave in digital holographic memory system.