Peicheng Liao

Towards a centralized controller for silicon photonic MZI-based interconnects

An FPGA-based centralized controller for a low-port 4×4 SiP multi-stage MZI-based switch is experimentally investigated with 10 Gb/s payload data. Packet contention resolutions and scheduling latencies are studied.

Gain Effect on Scalable Energy-Proportional SOA-Based Optical Space Switches

Energy-proportional optical interconnections are enabled by semiconductor optical amplifiers (SOAs) remaining off (or idle) when not routing data. In this letter, the physical layer scalability of SOA-based optical space switches configured with different gain and loss is assessed using an experimental recirculating loop. Results show that for a gain/loss configuration of 13.0 dB, optical multichannel packets successfully propagate through a series of 14 SOAs with a bit-error-rate <; 10-9, which indicates that a single-stage space switch can scale up to 109 ports. Scalability improves for lower gain/loss configuration at the cost of more SOAs per routing path. As expected, scalability is limited by cross-gain modulation and optical signal-to-noise ratio degradation, but their detrimental impact depends on the architecture configuration.

Ultradense Silicon Photonic Interface for Optical Interconnection

A scalable ultradense silicon photonic interface with 61 compact vertical grating couplers on a pitch of 42.3 μm is designed and fabricated to match a pitch reducing optical fiber array (PROFA) hexagonal channel pattern. Experimental results show that the designed grating couplers with a minimum insertion loss of 4.5 dB and a 3-dB bandwidth of 50 nm are obtained. The crosstalk between different channels is less than -50 dB and the maximum loss difference across the PROFA interface is ~0.7 dB. High-speed data transmission indicates that a bandwidth density as large as 27 Tb/s/mm2 could be achieved within a footprint of 0.096 mm2, demonstrating the potential of silicon photonics for broadband optical interconnection.

Gain effect on the scalability of soa-based optical space switches

Scalability is assessed by propagating WDM packets through multiple SOAs using a loop. Experimental results show that high SOA gain is more energy-efficient for single-stage space switch while low gain enhances the scalability of multi-stage architectures.

Dispersion-Tuned Harmonically Mode-Locked Fiber Laser

A dispersion-tuned harmonically mode-locked fiber laser is demonstrated using a reflective semiconductor optical amplifier (RSOA) and a chirped fiber Bragg grating. The laser is controlled by modulating the RSOA with a RF signal. The laser performance in terms of tunable bandwidth, pulsewidth, spectral width, output power, and optical signal to noise ratio (OSNR) is studied with respect to their dependence on the injected current levels to the RSOA. This letter indicates that lasing at higher harmonic order results in broaden temporal pulse width, larger spectral width, and lower OSNR. Narrower spectral width is obtained with lower modulation current causing less longitudinal modes to lase. A second synchronously gated RSOA is used to further amplify the laser with peak power up to 0 dBm with a constant output spectrum maintained at all wavelengths and reduced noise between pulses.

RODIN — Energy-proportional soa-based optical interconnect for large computing platforms

The idle mode of switching gates leads to energy-proportional interconnection networks while operating conditions and performance have an impact on their scalability. SOA-based gates are modeled and their operating conditions are optimized for scalability.

Ultra-dense optical I/O interface for Silicon photonic interconnects

An ultra-dense optical off-chip I/O interface consisting of 61 grating couplers matching the pitch of a commercial two-dimensional fiber array enables tremendous bandwidth density on the order of tens of Tb/s/mm2 towards high throughput Silicon photonics.

Low-Cost Dispersion-Tuned Active Harmonic Mode-Locked Laser With a 3-cm Coherence Length

We propose a low-cost dispersion-tuned actively mode-locked laser with long coherence length (up to 3 cm) by combining a wide-band, high reflectivity, and high-dispersion chirped fiber Bragg grating (CFBG) with a reflective semiconductor optical amplifier (RSOA). The dependence of the tuning characteristics on the varying physical length of CFBG in the cavity is studied experimentally and theoretically in the CFBG and RSOA based laser for the first time. The results show that the wavelength tuning range reduces when the harmonic number is increasing. Moreover, the high-dispersion and high-reflectivity CFBG yields high optical signal to noise ratio (>48 dB), narrow spectral width (lower than 0.033 nm), and more than 3-cm coherence length in the harmonically mode-locked laser. This low-cost dispersion tuned mode-locked laser with wide tuning range, stable and small time-bandwidth product, and long coherence length can lead to enhanced applications.