Micromirror With Multiple Digitized Angles for Free Space Optical Crossconnects

2003 ◽  
Author(s):  
Jianglong Zhang ◽  
Y. C. Lee
Keyword(s):  
Material Properties ◽  
Free Space ◽  
Bottom Electrode ◽  
Beam Steering ◽  
Optical Switches ◽  
Design Parameters ◽  
Mirror Surface ◽  
Free Space Optical ◽  
Control Electronics ◽  
Digital Levels

To eliminate or lower the power consumption and complexity of the control electronics that limit the applications of analog optical switches, beam steering devices and other micromirrors, this paper presents micromirrors with multiple digitized angles for free space optical crossconnects. Device requirements defined by a dual-lens and dual-micromirror array system are used to guide the designs of the micromirrors. The micromirrors with multiple digitized angles are designed using MUMPs, a MEMS foundry process, and simulated by full coupled-domain FEM/BEM. The effects of the design parameters on the digitized angles are analyzed. These parameters are flexure configuration, connector beam configuration, plate configuration and bottom electrode configuration. With these effects known, a micromirror is successfully designed for the desired optical system. Such a mirror’s repeatability is expected to be about 0.06°, which is obtained by a preliminary experimental study of a similar device. The repeatability of the digital levels highly depends on the initial gap between the mirror surface and the bottom electrode, flexure configuration, connector beam configuration and material properties.

scholarly journals Free-Space Optical Beam Steering for Wireless Communications

2021 ◽  
Author(s):  
Christopher Mekhiel
Keyword(s):  
Wireless Communications ◽  
Cross Talk ◽  
High Frequency ◽  
Free Space ◽  
Beam Steering ◽  
Optical Beam ◽  
Outdoor Environment ◽  
Switching Frequency ◽  
External Signal ◽  
Free Space Optical

The implementation of optical of wireless communications (OWC) requires the use of a light-emitting-diode (LED) or laser diode (LD). Due to significant path loss exhibited by these sources in an outdoor environment, an unobstructed point-to-point link must be maintained in order to increase the signal-to-noise ratio (SNR) at the receiver. This thesis considers a solution to alleviate the fundamental limitations of the OWC channel in an outdoor environment by investigating optical beam steering (OBS) to increase the signal strength in the desired direction. Conventional methods to implement on OBS use a microelectromechanical (MEMS) mirror or a spatial light modulator (SLM) which both suffer from low switching frequency. A high frequency OBS device can be created by using optical phased array (OPA). An electro-optic modulator (EOM) such as LiNbO3 can be used to create an OPA but can not be directly integrated in silicon. For monolithic silicon-on-insulator (SOI) solutions, previous literature uses thermo-optic couplers on SOI to implement the OPA, however this introduces the issue of thermal cross-talk. Therefore, this thesis focuses on the use of silicon as the EOM for use in an OPA to create a high frequency monolithic OBS. Our contributions consist of providing a design method for a OBS SOI device which exhibits minimum internal cross-talk and provides propagation in free-space with high directivity and a wide steering range. Additionally, propose the use of an internal heterodyne optical phase locked loop (PLL) to stabilize the OBS instead of an external signal processor for phase correction. This optical PLL reduces beam jitter, minimizes beam squint, and provides active tracking for the output beam towards the receiver. We have also characterized a shadowing scenario in an OWC channel which OBS has the potential to alleviate. Moreover, we simulated the optical far-field radiation pattern from a SOI waveguide to free-space which has not been demonstrated in previous research. Finally, our simulation results of a SOI OPA demonstrates the coherent combining capability of OBS using MEEPTtm and the Optiwavetm suite.

scholarly journals Free Space Intra-Datacenter Interconnects Based on 2D Optical Beam Steering Enabled by Photonic Integrated Circuits

Photonics ◽  
2018 ◽  
Vol 5 (3) ◽  
pp. 21 ◽  
Author(s):  
Charidimos Chaintoutis ◽  
Behnam Shariati ◽  
Adonis Bogris ◽  
Paul Dijk ◽  
Chris Roeloffzen ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Integrated Circuit ◽  
Data Center ◽  
Free Space ◽  
Large Scale ◽  
Beam Steering ◽  
Optical Beam ◽  
Switching Network ◽  
Free Space Optical ◽  
Data Center Networks

Data centers are continuously growing in scale and can contain more than one million servers spreading across thousands of racks; requiring a large-scale switching network to provide broadband and reconfigurable interconnections of low latency. Traditional data center network architectures, through the use of electrical packet switches in a multi-tier topology, has fundamental weaknesses such as oversubscription and cabling complexity. Wireless intra-data center interconnection solutions have been proposed to deal with the cabling problem and can simultaneously address the over-provisioning problem by offering efficient topology re-configurability. In this work we introduce a novel free space optical interconnect solution for intra-data center networks that utilizes 2D optical beam steering for the transmitter, and high bandwidth wide-area photodiode arrays for the receiver. This new breed of free space optical interconnects can be developed on a photonic integrated circuit; offering ns switching at sub-μW consumption. The proposed interconnects together with a networking architecture that is suitable for utilizing those devices could support next generation intra-data center networks, fulfilling the requirements of seamless operation, high connectivity, and agility in terms of the reconfiguration time.

Performance of a free space optical link employing DCO-OFDM modulated Gaussian-beam

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jayashree Ratnam ◽  
Sabita Mali
Keyword(s):  
Free Space ◽  
Average Power ◽  
Optical Beam ◽  
Index Structure ◽  
Design Parameters ◽  
Communication Link ◽  
Transmitted Power ◽  
Free Space Optical ◽  
Trade Offs ◽  
Dc Bias

Abstract The paper studies the performance of a free space optical communication link, which consists of a Gaussian Laser beam employing direct-current-biased optical frequency division multiplexing (DCO-OFDM) modulation, to carry information. While optical multi-carrier modulation is capable of alleviating multi-path fading, higher transmit power by virtue of dc-bias, helps the optical beam in partially off-setting signal intensity loss due to beam divergence in free space channel. In order to reduce the overall transmitted power apart from avoiding nonlinearities due to high peak-to-average-power-ratio (PAPR), we utilize a PAPR-dependent dc-bias, to generate a DCO OFDM light beam from a pre-clipped electrical baseband OFDM signal. The radiated optical beam encounters turbulence-induced impairments like beam-spreading, beam-wander, etc., which affect the signal-to-noise ratio (SNR) of the received data symbols. Further signal pre-clipping and optical source linearity generate clipping noise components resulting in compromised receiver performance or reduction of span length, to achieve target bit rate error (BER). In this paper, we derive an analytical model for evaluating the performance of the free-space optical (FSO) link, by modeling various impairments as noise variances and characterizing atmospheric turbulence by refractive index structure parameter under weak- and strong-turbulent conditions. Numerical results are obtained by varying system design parameters in the model, which graphically provide useful insight on the power penalties and various trade-offs involved in operating the link on a longer span, at a higher data rate, and with reduced transmitted power through pre-clipping while ensuring desired signal BER.

Computer-controlled, adaptive beam steering, implemented in a FLC-SLM free-space optical switch

2000 ◽  
Author(s):  
Mathias Johansson ◽  
Sverker Hård ◽  
Brian Robertson ◽  
Ilias Manolis ◽  
Timothy Wilkinson ◽  
...  
Keyword(s):  
Free Space ◽  
Optical Switch ◽  
Beam Steering ◽  
Free Space Optical ◽  
Computer Controlled

New Class of Rearrangeable Nonblocking Multicast Free-Space Optical Switches

2016 ◽  
Vol 8 (8) ◽  
pp. 569 ◽  
Author(s):  
Abdelbaset S. Hamza ◽  
Jitender S. Deogun ◽  
Dennis R. Alexander
Keyword(s):  
Free Space ◽  
Optical Switches ◽  
Free Space Optical ◽  
New Class

Free-space optical switches based on polarization

2001 ◽  
Author(s):  
Qiaoyan Hu ◽  
Mingcui Cao ◽  
Fengguang Luo ◽  
Wei Tan
Keyword(s):  
Free Space ◽  
Optical Switches ◽  
Free Space Optical
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