Opto-VLSI Processor Research Articles

Opto-VLSI-Based Dynamic RF Signal Combiner

An Opto-VLSI based dynamic RF signal combiner structure is proposed and experimentally demonstrated. The structure utilizes an Opto-VLSI processor in conjunction with an optical fiber array, a photo-detector, and a 4-f imaging lens system to dynamically combine multiple analog RF signals into a single output RF port with a user-defined combination ratio. A proof-of-concept $2\times 1$ analogue RF signal combiner is experimentally demonstrated, and experimental results show that RF signal combination with arbitrary ratio can be achieved by uploading different optimized phase holograms onto the Opto-VLSI processor.

1×N wavelength selective adaptive optical power splitter for wavelength-division-multiplexed passive optical networks

Abstract In this paper, a 1× N wavelength selective adaptive optical power splitter (WS-AOPS) suitable for wavelength-division-multiplexed passive optical network (WDM-PON) systems is proposed and experimentally demonstrated based on the use of an Opto-VLSI processor. The input signals with different wavelengths can be split and coupled into N output ports with variable splitting ratios. A proof-of-principle 1×2 WS-AOPS structure driven by optimized multicasting phase holograms uploaded onto the Opto-VLSI processor is developed, demonstrating an arbitrary splitting ratio for each input wavelength channel over C-band.

A $1 \times N$ Lossless Adaptive Optical Power Splitter Employing an Opto-VLSI Processor

We propose and demonstrate the concept of a novel 1 × N lossless adaptive optical power splitter (OPS) structure integrating a software-driven Opto-VLSI processor, optical amplifiers, and an array of 4-f imaging systems. The active area of the Opto-VLSI processor is divided into M pixel blocks driven by multicasting phase holograms and aligned with an M-element lens array and a fiber array, thus forming an array of 4-f imaging systems. Each 4-f imaging system is capable of collimating and adaptively splitting an input optical beam emerging from an optical fiber and then coupling the split beams into different output fiber ports, thus realizing dynamic optical power splitting. The Opto-VLSI processor is driven by optimized multicasting phase holograms that adaptively split an incident laser beam along different angles; thus, user-defined splitting ratios can be achieved. Experimental results show that the optical amplifiers compensate for the splitting and the insertion losses, making the adaptive OPS lossless.

Opto-VLSI-based N × M wavelength selective switch

In this paper, we propose and experimentally demonstrate a novel N × M wavelength selective switch (WSS) architecture based on the use of an Opto-VLSI processor. Through a two-stage beamsteering process, wavelength channels from any input optical fiber port can be switched into any output optical fiber port. A proof-of-concept 2 × 3 WSS structure is developed, demonstrating flexible wavelength selective switching with an insertion loss around 15 dB.

Opto-VLSI-Based Beamformer for Radio-Frequency Phased-Array Antennas

An Opto-VLSI-based tunable beamformer for radio frequency (RF) smart antennas is reported and its concept is demonstrated. RF beam steering is achieved by uploading appropriate phase holograms onto the Opto-VLSI processor so that RF true-time delays (TTDs) are independently generated for each element of the antenna array by simply using several erbium-doped fiber amplifier (EDFA) loops to realize independent tunable fiber lasers in conjunction with a dispersive optical fiber. Experimental results demonstrate RF beam steering up to 30° with a 4-element linear patch antenna array operating at 1.85 GHz.

Tunable dual-wavelength fiber laser based on an opto-VLSI processor and four-wave mixing in a photonic crystal fiber

A stable wavelength and wavelength spacing tunable dual-wavelength fiber laser based on an Opto-very-large-scale-integration (Opto-VLSI) processor and four-wave mixing (FWM) in a high-nonlinear photonic crystal fiber is experimentally demonstrated. The results show that the line width of the tunable dual-wavelength fiber laser is 0.02 nm, and the wavelength spacing can be tuned from 0.8 nm to 4 nm with a 0.15 nm step. Under the influence of the FWM, the uniformity is below 0.6 dB and the measured side mode suppression ratio (SMSR) is above 45 dB.

Reconfigurable optical power splitter/combiner based on Opto-VLSI processing

A novel 1×4 reconfigurable optical splitter/combiner structure based on Opto-VLSI processor and 4-f imaging system with high resolution is proposed and experimentally demonstrated. By uploading optimized multicasting phase holograms onto the software-driven Opto-VLSI processor, an input optical signal is dynamically split into different output fiber ports with user-defined splitting ratios. Also, multiple input optical signals are dynamically combined with arbitrary user-defined weights.

Tunable Multiwavelength Fiber Ring Lasers Based on an Opto-VLSI Processor

We propose and experimentally demonstrate the principle of a tunable multiwavelength fiber ring laser based on the use of an opto-very-large-scale-integration (Opto-VLSI) processor in conjunction with an erbium-doped fiber amplifier and a semiconductor optical amplifier. Multiple wavelength channels within the gain range of the optical amplifiers can independently be generated, tuned and/or switched on/off, through applying appropriate phase holograms onto the Opto-VLSI processor. A tunable five-wavelength fiber ring laser of output power of around +6 dBm per channel and a sidemode suppression ratio (SMSR) greater than 30 dB is demonstrated. The tunable multiwavelength fiber lasers have excellent stability at room temperature.

Adaptive Optical Splitter Employing an Opto-VLSI Processor and a 4-$f$ Imaging System

A novel adaptive optical splitter structure employing an Opto-VLSI processor and 4-f imaging system is proposed and experimentally demonstrated. By driving the Opto-VLSI processor with computer generated multicasting phase holograms, an input optical signal launched into an input optical fiber port can be split and coupled into many output optical fiber ports with arbitrary splitting ratios. A proof-of-principle 1 × 2 adaptive optical splitter structure driven by optimized multicasting phase holograms uploaded onto the Opto-VLSI processor is developed, demonstrating an arbitrary splitting ratio over a wavelength range exceeding 50 nm.

Adaptive multi/demultiplexers for optical signals with arbitrary wavelength spacing

We propose and demonstrate the principle of a novel adaptive wavelength division multiplexer/demultiplexer structure based on Opto-VLSI processing. By driving an Opto-VLSI processor with an appropriate phase hologram, optical signals of arbitrary wavelengths from different input fiber ports can be multiplexed into a common output fiber port. In addition, wavelength division multiplexed channels of arbitrary wavelength spacings can also be demultiplexed and dynamically routed into arbitrary output fiber ports. A proof-of-principle 1x3 adaptive multiplexer/demultiplexers is experimentally demonstrated.

Tunable multi-wavelength fiber lasers based on an Opto-VLSI processor and optical amplifiers

A multi-wavelength tunable fiber laser based on the use of an Opto-VLSI processor in conjunction with different optical amplifiers is proposed and experimentally demonstrated. The Opto-VLSI processor can simultaneously select any part of the gain spectrum from each optical amplifier into its associated fiber ring, leading to a multiport tunable fiber laser source. We experimentally demonstrate a 3-port tunable fiber laser source, where each output wavelength of each port can independently be tuned within the C-band with a wavelength step of about 0.05 nm. Experimental results demonstrate a laser linewidth as narrow as 0.05 nm and an optical side-mode-suppression-ratio (SMSR) of about 35 dB. The demonstrated three fiber lasers have excellent stability at room temperature and output power uniformity less than 0.5 dB over the whole C-band.

A novel reconfigurable optical interconnect architecture using an Opto-VLSI processor and a 4-f imaging system

A novel reconfigurable optical interconnect architecture for on-board high-speed data transmission is proposed and experimentally demonstrated. The interconnect architecture is based on the use of an Opto-VLSI processor in conjunction with a 4-f imaging system to achieve reconfigurable chip-to-chip or board-to-board data communications. By reconfiguring the phase hologram of an Opto-VLSI processor, optical data generated by a vertical Cavity Surface Emitting Laser (VCSEL) associated to a chip (or a board) is arbitrarily steered to the photodetector associated to another chip (or another board). Experimental results show that the optical interconnect losses range from 5.8dB to 9.6dB, and that the maximum crosstalk level is below -36dB. The proposed architecture is tested for high-speed data transmission, and measured eye diagrams display good eye opening for data rate of up to 10Gb/s.

Opto-VLSI-based tunable photonic RF filter

In this paper, an Opto-Very-Large-Scale-Integrated (Opto-VLSI) based tunable photonic radio frequency (RF) filter structure is proposed and numerically simulated. The structure comprises a reconfigurable Opto-VLSI processor capable of arbitrarily steering optical beams of different wavelengths, a diffraction grating for wavelength division demultiplexing, and high-dispersion fibres for true-time delaying RF-modulated wavebands. The proposed structure has the ability to generate arbitrary wavebands and weights for realizing any RF filter responses. The proof-of-concept of the tunable photonic RF signal processor is also experimentally demonstrated by tuning its free-spectral range and altering its shape factor through optical beam steering.

Opto-VLSI-based tunable single-mode fiber laser

A new tunable fiber ring laser structure employing an Opto-VLSI processor and an erbium-doped fiber amplifier (EDFA) is reported. The Opto-VLSI processor is able to dynamically select and couple a waveband from the gain spectrum of the EDFA into a fiber ring, leading to a narrow-linewidth high-quality tunable laser output. Experimental results demonstrate a tunable fiber laser of linewidth 0.05 nm and centre wavelength tuned over the C-band with a 0.05 nm step. The measured side mode suppression ratio (SMSR) is greater than 35 dB and the laser output power uniformity is better than 0.25 dB. The laser output is very stable at room temperature.

An integrated reconfigurable optical add-drop multiplexer based on using an opto-VLSI processor and a 4-f imaging system

A novel integrated reconfigurable optical add-drop multiplexer (ROADM) structure is proposed and demonstrated experimentally. The ROADM employs an interface substrate that enables the integration of a fiber-lens collimator array and an Opto-VLSI processor to realise a 4-f imaging system through optical beam steering. Phase hologram optimization of the Opto-VLSI processor is investigated, for maximizing the number of wavelength channels while keeping adequate insertion loss and crosstalk levels. Experimental results are shown, which demonstrate a broadband operation and the principle of the ROADM with crosstalk of less than −30.5 dB and insertion loss of less than 6 dB for the drop and through operation modes.

An Opto-VLSI-based reconfigurable optical adddrop multiplexer employing an off-axis 4-f imaging system

A novel reconfigurable optical add-drop multiplexer (ROADM) structure is proposed and demonstrated experimentally. The ROADM structure employs two arrayed waveguide gratings (AWGs), an array of optical fiber pairs, an array of 4-f imaging microlenses that are offset in relation to the axis of symmetry of the fiber pairs, and a reconfigurable Opto-VLSI processor that switches various wavelength channels between the fiber pairs to achieve add or drop multiplexing. Experimental results are shown, which demonstrate the principle of add/drop multiplexing with crosstalk of less than -27dB and insertion loss of less than 8dB over the Cband for drop and through operation modes.

Tunable Photonic Microwave Filters Based on Opto-VLSI Processors

A tunable photonic microwave filter structure utilizing an opto-very-large scale integration (opto-VLSI) processor is proposed and experimentally demonstrated. The opto-VLSI processor slices a radio-frequency (RF)-modulated wideband light source into wavebands of arbitrary weights and incremental delay times to realize a tunable RF filter response. Experimental results demonstrate a tunable microwave filter that can simply be reconfigured with high flexibility via a software-driven opto-VLSI processor. Theoretical simulations are in good agreement with the experimental results.

Opto-VLSI-based photonic true-time delay architecture for broadband adaptive nulling in phased array antennas

This paper proposes a novel Opto-VLSI-based tunable true-time delay generation unit for adaptively steering the nulls of microwave phased array antennas. Arbitrary single or multiple true-time delays can simultaneously be synthesized for each antenna element by slicing an RF-modulated broadband optical source and routing specific sliced wavebands through an Opto-VLSI processor to a high-dispersion fiber. Experimental results are presented, which demonstrate the principle of the true-time delay unit through the generation of 5 arbitrary true-time delays of up to 2.5 ns each.

Novel broadband reconfigurable optical add-drop multiplexer employing custom fiber arrays and Opto-VLSI processors

A reconfigurable optical add/drop multiplexer (ROADM) structure based on using a custom-made fiber array and an Opto-VLSI processor is proposed and demonstrated. The fiber array consists of N pairs of angled fibers corresponding to N channels, each of which can independently perform add, drop, and thru functions through a reconfigurable Opto-VLSI beam steerer. Experimental results show that the ROADM structure can attain an average add, drop/thru insertion loss of 5.5 dB and a uniformity of 0.3 dB over a wide bandwidth from 1524 nm to 1576 nm, and a drop/thru crosstalk level as small as -40 dB.

Reconfigurable encoder-decoder structure for 2D OCDMA systems

We propose and experimentally demonstrate a 2.5Gbits/s reconfigurable encoder-decoder structure that can be used for two-dimensional (time-wavelength) optical code-division multiple access (OCDMA) systems. Each encoder and decoder is constructed using a single opto-very-large-scale-integrated (VLSI) processor for encoding N users, thus eliminating the need for optical switching between encoders. The opto-VLSI processor synthesizes wavelength codewords through computer-generated digital phase holograms, which can switch the wavelength through different true-time-delay paths. The encoded signal can be successfully retrieved at the decoder side only when the digital phase holograms of the encoder and the decoder are matched. The system performance is measured in terms of the generated autocorrelation and cross-correlation functions as well as eye diagrams.