Add-drop Switch Research Articles

Feasibility of chipscale integration of single-photon switched digital loop buffer

A strategy for realizing a microchip-scale single-photon digital loop buffer controlled by low-voltage electronic signals is studied in the context of integrated photonics. A potential implementation for bridging a gap between other technologies uses a recirculating loop architecture based on advances in low-loss passive waveguides and a fast electro-optic add-drop switch. Though the requirements of single-photon buffers are demanding, our analysis suggests that a voltage-controlled, room-temperature catch-and-store short-term quantum memory for light on a chip may be feasible in certain regimes.

Heterogeneously integrated III–V-on-Si microring resonators: a building block for programmable photonic integrated circuits

Beyond various application-specific photonic integrated circuits (PICs), a programmable PIC comprising identically designed generic building blocks with multiple active functionalities under different operational conditions is an attractive design option. Here, we propose and demonstrate proof-of-concept experiments of a heterogeneously integrated III–V-on-Si microring resonator (MRR) as such a versatile building block. The MRR can function as an electro-optical channel add-drop switch with signal amplification, a directly modulated injection laser, or a microcavity photodetector under different electrical bias conditions. We discuss the fabrication process for our heterogeneous integration platform based on an atomic layer deposition-assisted molecular bonding technique.

On-Chip Router Elements Based on Silicon Hybrid Plasmonic Waveguide

We have proposed and investigated micro-ring add-drop switch and M-Z interferometric element for on-chip router applications based on silicon hybrid plasmonic waveguide. The proposed silicon hybrid plasmonic waveguide possesses lower propagation loss compared with conventional plasmonic metal-insulator-metal waveguide. By employing this low loss waveguide, it is found that the proposed ring add-drop switch possesses high transmission efficiency (−1 dB), and the extinction ratio can be as high as 30 dB at $1.556~\mu \text{m}$ . In addition, the transmission efficiency of drop port for the M-Z interferometric element can be −1.15 dB at $1.55~\mu \text{m}$ . The designed elements are essential for the on-chip router in optical interconnect.

A wavelength-selective add-drop switch using silicon microring resonator with a submicron-comb electrostatic actuator

Electrostatic comb-drive micro actuator with submicron comb fingers was connected to silicon microring resonator to consist a wavelength-selective add-drop switch at 1.5 microm wavelength with variable coupling mechanism. A 500 nm wide 260 nm thick 63.4 microm long silicon microring waveguide was suspended in air with low-loss suspension arms. The air gap between the microring and the input/output waveguides was adjusted by the voltage applied to the comb actuator to vary the coupling efficiency. Transmittance from the input port to a drop port was varied 32.9dB by applying the voltages from 0V to 28.2V. At 28.2V, transmittance from the input port to a through port decreased by 7.83 dB from that at 0V, and 55% of the intensity was transmitted to the drop port. The full-width-half-maximum bandwidth of the dropped light was 0.5 nm, corresponding to a Q-value of 3150.

Moderate-to-high optical-isolation reconfigurable 1×2 fiber-optic add-drop switches using a dense wavelength division multiplexing thin-film filter

We propose and experimentally demonstrate thin-film filter- (TF) based reconfigurable 1 x 2 fiber-optic add-drop switch (FADS) structures. Our key idea is to locate a movable mirror oriented at a desired angle near the TF to switch the desired wavelength optical beams to the wanted switching ports. Our first moderate-optical-isolation TF-based reconfigurable 1 x 2 FADS is in a transmissive design. Another TF-based reconfigurable 1 x 2 FADS structure is in a retroreflective configuration, and it gives a very low optical-coherent cross talk. Our experimental proof of concept using an off-the-shelf four-cavity TF measured center wavelength at 1,545.749 nm and a 0.8 mm x 0.8 mm x 0.15 mm movable mirror confirms a -19 dB and a much improved <-53 dB optical-coherent cross talk for our transmissive and retroreflective configurations, respectively.

Fiber-optic tunable multiwavelength variable attenuator and routing module designs that use bulk acousto-optics

A compact fiber-coupled bulk acousto-optical multiwavelength variable optical attenuator module design that uses a retroreflective double-pass geometry within a single bulk acousto-optic tunable filter device is presented. The proposed attenuator module demonstrates a high 17-dB notch dynamic range at a low 100-mW drive power and uses a single bulk collinear-interaction acousto-optic tunable-filter device. Experiments show a low (<1.8-dB) fiber-to-fiber insertion loss with a fast 34-micros speed within a wide 1520-1640-nm agile multinotch band. The basic broadband attenuator module design is extended to allow for efficient architectures for routing modules such as agile drop filters, analog hitless tap filters, and digital add-drop switches.

A reconfigurable thin-film filter-based 2 x 2 add-drop fiber-optic switch structure

A reconfigurable 2 /spl times/ 2 add-drop fiber-optic switch structure is proposed by incorporating the independent mechanical control and alignment of an off-the-shelf thin-film filter with a reflective optical element. Cascading several 2 /spl times/ 2 add-drop switches gives a low-cost polarization-independent wavelength routing system with the limitation in optical loss that can be compensated by using optical amplifiers. The experimental result indicates a measured average optical loss of <1.30 dB at the center wavelength. In addition, the measured optical coherent crosstalk values at the center wavelength are -15 and -22 dB when the thin-film filter and the mirror are in the optical path, respectively. A very low polarization-dependent loss of <0.07 dB is also investigated.

Wavelength conversion in optical packet switching

A detailed traffic analysis of optical packet switch design is performed. Special consideration is given to the complexity of the optical buffering and the overall switch block structure is considered in general. Wavelength converters are shown to improve the traffic performance of the switch blocks for both random and bursty traffic. Furthermore, the traffic performance of switch blocks with add-drop switches has been assessed in a Shufflenetwork showing the advantage of having converters at the inlets. Finally, the aspect of synchronization is discussed through a proposal to operate the packet switch block asynchronously, i.e. without packet alignment at the input.

Liquid crystal and grating-based multiple-wavelength cross-connect switch

We propose and demonstrate a liquid-crystal and grating based optical cross-connect add-drop switch that operates simultaneously on several wavelengths channels. We demonstrate an 8 channels switch with 4 nm channel spacing, a flat-top frequency response and 30 dB extinction ratio. >