Topic
Optical modulator
About: Optical modulator is a research topic. Over the lifetime, 14068 publications have been published within this topic receiving 196932 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this paper, the properties of a liquid crystal television to be used as a spatial modulator of the polarization of a laser beam are studied and a new model is proposed that takes into account additional birefringence effects resulting from border effects near the television windows.
Abstract: The properties of a liquid crystal television to be used as a spatial modulator of the polarization of a laser beam are studied. It is found that the model most commonly used for the display description does not adequately reproduce the transmission through crossed polarizers. A new model is proposed that takes into account additional birefringence effects resulting from border effects near the television windows. With this correction, the anomalous behavior of the television is explained and the throughput for different configurations is properly predicted.
60 citations
TL;DR: It is illustrated that the phase-only liquid crystal spatial light modulator (LC SLM) can be used for optical testing and the large phase change and the phase modulation precision are discussed.
Abstract: We illustrate that the phase-only liquid crystal spatial light modulator (LC SLM) can be used for optical testing. The large phase change and the phase modulation precision are discussed. The computer generated holograms (CGH) method is used to acquire the significant phase modulation. And the phase modulating characteristics of the LC SLM are measured. It shows the phase modulation depth is more than 2π and the modulation precision is down to 1/14λ (PV) and 1/100λ (rms) (λ=632.8nm). In order to verify this method, the former surface of a convex lens is tested by ZYGO interferometer. The parallel straight fringes are obtained. It is shown that PV is 1/3λ and rms is 1/20λ after compensated by the LC SLM.
60 citations
TL;DR: A compact experimental system is constructed that uses a 635-nm diode laser in which a fixed encrypted 0/pi binary phase mask is decrypted by a binary phase key produced electronically on the spatial light modulator.
Abstract: We present a system for the implementation of phase-only optical decryption of an encrypted fixed phase mask. We achieve decryption by superimposing a decrypting phase key, implemented on a phase-only spatial light modulator with an encrypted phase mask in two equivalent image planes in an optical system. The decrypted phase information is retrieved by the generalized phase-contrast technique. We have constructed a compact experimental system that uses a 635-nm diode laser in which a fixed encrypted 0/pi binary phase mask is decrypted by a binary phase key produced electronically on the spatial light modulator. The key is aligned by electronic scrolling of its position with respect to the mask.
60 citations
Patent•
11 Mar 2003
TL;DR: In this article, a modulator controller monitors the output optical signal power, optimizes the bias setting for the data modulator and the PM, and optimizes phase relationship between the pulse and data components of the modulated optical signal.
Abstract: In an optical transmitter, continuous wave light from a laser passes through a data modulator (DM) for non-return-to-zero (NRZ) encoding of a data stream and through a pulse modulator to add return-to-zero encoding to the modulated optical signal. A modulator controller monitors the output optical signal power, optimizes the bias setting for the DM and the PM, and optimizes the phase relationship between the pulse and data components of the modulated optical signal. For each optimization, a low amplitude and low frequency dither signal is injected at appropriate points in the modulator. A single photo detector and electrical receiver are used in a multiplexed fashion to monitor the optical output signal and derive separate feedback signals. Remaining control circuitry forces a null in a respective residual dither component in the optical output signal to maintain the desired bias level or phase alignment.
60 citations
TL;DR: A carrier-depletion optical modulator with the driving voltage swing of 2 V and the extinction ratio of 12.79 dB at 12.5 Gbit/s is demonstrated.
Abstract: We demonstrate a carrier-depletion Mach-Zehnder silicon optical modulator, which is compatible with CMOS fabrication process and works well at a low driving voltage. This is achieved by the optimization of the coplanar waveguide electrode to reduce the electrical signal transmission loss. At the same time, the velocity and impedance matching are both considered. The 12.5 Gbit/s data transmission experiment of the fabricated device with a 2-mm-long phase shifter is performed. The driving voltages with the swing amplitudes of 1 V and 2 V and the reverse bias voltages of 0.5 V and 0.8 V are applied to the device, respectively. The corresponding extinction ratios are 7.67 and 12.79 dB.
60 citations