Demonstration of Multi-Casting in a 1 × 9 LCOS Wavelength Selective Switch

Robertson, Brian; Yang, Haining; Redmond, M.M.; Collings, N.; Moore, J.; Liu, Jinsong; Jeziorska-Chapman, Anna M.; Pivnenko, Mike; Lee, Sharon; Wonfor, A.; White, I.H.; Crossland, W. A.; Chu, Daping

doi:10.1109/jlt.2013.2293919

Cited by 59 publications

(33 citation statements)

References 22 publications

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“…The optical power spectrum of the bandpass filter can be obtained by squaring Eq. (6). The insert loss of the WSS based on two-dimensional beam steering mainly comes from the blazed gratings, LCOS, collimator, and the Fourier lens.…”

Section: Resultsmentioning

confidence: 99%

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Research of two-dimensional beam steering in LCOS-based wavelength selective switch

Yang

Jing

et al. 2015

Appl. Opt.

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Section: Resultsmentioning

confidence: 99%

“…1(a) and 1(b). Each area of the LCOS SLM covered by a beam is configured to operate as an independent subhologram of pixel dimensions M x × M y [6]. The angle between the blazed grating plane and x-y plane before or after coordinate transformation is 49.5 deg, which is the blaze angle.…”

Section: Introductionmentioning

confidence: 99%

Research of two-dimensional beam steering in LCOS-based wavelength selective switch

Yang

Jing

et al. 2015

Appl. Opt.

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“…Phase-only nematic LCOS devices are now becoming the dominant optical switch technology in reconfigurable add-drop multiplexers (ROADMs). [102][103][104][105] One of the best performances for ROADMs was demonstrated by Robertson et al 19 recently and implements a multifunctional 139 wavelength selective switch (WSS) based on a phase-only nematic LCOS device with 27.6 dB of insertion loss and 219.4 dB of the worst-case crosstalk for a channel spacing of 100 and 200 GHz. These devices offer better control of the optical wavefronts and more flexibility than MEMS (micro electro mechanical systems) devices.…”

Section: Algorithms Of Hologram Generation For Phase-only Lcos Devicementioning

confidence: 99%

“…Unlike amplitude-modulating LCOS devices (mainly for video and image projections), phase-only modulating LCOS devices have a wide range of applications based on the spatial modulation of coherent lights, [14][15][16] including real-time holography, 17 optical correlators, 18 wavelength selective switches, 19,20 reconfigurable optical add-drop multiplexers [20][21][22] and diffractive optical components. [23][24][25] The first attempt to drive an LC pixel array from a single crystal silicon active backplane was proposed by Ernstoff et al 26 in the early 1970s.…”

Section: Brief Introduction To Lcos Devicesmentioning

confidence: 99%

Fundamentals of phase-only liquid crystal on silicon (LCOS) devices

2014

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This paper describes the fundamentals of phase-only liquid crystal on silicon (LCOS) technology, which have not been previously discussed in detail. This technology is widely utilized in high efficiency applications for real-time holography and diffractive optics. The paper begins with a brief introduction on the developmental trajectory of phase-only LCOS technology, followed by the correct selection of liquid crystal (LC) materials and corresponding electro-optic effects in such devices. Attention is focused on the essential requirements of the physical aspects of the LC layer as well as the indispensable parameters for the response time of the device. Furthermore, the basic functionalities embedded in the complementary metal oxide semiconductor (CMOS) silicon backplane for phase-only LCOS devices are illustrated, including two typical addressing schemes. Finally, the application of phase-only LCOS devices in real-time holography will be introduced in association with the use of cutting-edge computer-generated holograms. The architecture of LCOS devices is similar to conventional LC devices except that a silicon backplane constitutes one of the substrates (Figure 1). The silicon CMOS backplane consists of the electronic circuitry that is buried underneath pixel arrays to provide a high 'fill factor'. The pixels are aluminum mirrors deposited on the surface of the silicon backplane. The incident light is transmitted through the LC layer with almost zero absorption. The integration of high-performance driving circuitry allows the applied voltage to be changed on each pixel, thereby controlling the phase retardation of the incident wavefront across the device. Currently, there are two types of light modulation using LCOS devices, amplitude modulation and phase modulation. In the former case, the amplitude of the light signal is modulated 6,7 by varying the linear polarzation direction of the incident light passing through a linear polarizer, the same principle used in a standard LC television. In the latter case, the phase delay is accomplished by electrically adjusting the optical refractive index along the light path, which is possible because of the non-zero birefringence of the LC materials in use but should be carefully characterized. [8][9][10][11][12][13] In a phase-only LCOS SLM modulator, no light absorption by polarizers or other light-absorbing components will occur, such that the maximum light efficiency can be expected.Currently, most of the conventional LC devices are not able to efficiently modulate the phase of an incident wavefront. For instance, the LC device structure using thin film transistors is not suitable for phase modulation because an appropriate electro-optic effect has not been used (see the section on 'Twisted nematic (TN) configuration' and the section on 'VAN configuration' for details). Moreover, the pixels of this type of device are too large to provide acceptably large diffraction angles. In addition, the pixel circuitry and connection tracks are in the light path such that the ...

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“…Figure 14 shows the maximum distance supported by the nodes, including insertion loss. The insertion loss of a passive splitter is around 3 dB, while that of a multicast WSS is around 5 6 dB [22], which reduces the maximum deployment distances to ∼40 and ∼25 km, respectively. The current implementation of QPAR has a very high insertion loss (an implementation with tri state MEMs has an inser tion loss of about 10 dB for 64 outputs), so we see it cannot support 40 km for more than 10 users per wavelength.…”

Section: ) Queuing Latencymentioning

confidence: 99%

Quasi-Passive Optical Infrastructure for Future 5G Wireless Networks: Pros and Cons

Gowda

Kazovsky

Wang

et al. 2016

J. Opt. Commun. Netw.

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Abstract-In this paper, we study the applicability of the quasi-passive reconfigurable (QPAR) device, a special type of quasi-passive wavelength-selective switch with flexible power allocation properties and no power consumption in the steady state, to implement the concept of reconfigurable backhaul for 5G wireless networks. We first discuss the functionality of the QPAR node and its discrete component implementation, scalability, and performance. We present a novel multi-input QPAR structure and the pseudo-passive reconfigurable (PPAR) node, a device with the functionality of QPAR but that is pseudo-passive during steady-state operations. We then propose mesh and hierarchical backhaul network architectures for 5G based on the QPAR and PPAR nodes and discuss potential use cases. We compare the performance of a QPAR-based single-node architecture with state-of-the-art devices. We find that a QPAR node in a hierarchical network can reduce the average latency while extending the reach and quality of service of the network. However, due to the high insertion losses of the current QPAR design, some of these benefits are lost in practice. On the other hand, the PPAR node can realize the benefits practically and is the more energy-efficient solution for high reconfiguration frequencies, but the remote optical node will no longer be passive. In this paper, we discuss the potential benefits and issues with utilizing a QPAR in the optical infrastructure for 5G networks.

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Demonstration of Multi-Casting in a 1 × 9 LCOS Wavelength Selective Switch

Cited by 59 publications

References 22 publications

Research of two-dimensional beam steering in LCOS-based wavelength selective switch

Research of two-dimensional beam steering in LCOS-based wavelength selective switch

Fundamentals of phase-only liquid crystal on silicon (LCOS) devices

Quasi-Passive Optical Infrastructure for Future 5G Wireless Networks: Pros and Cons

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