Error-free continuously-tunable delay at 10 Gbit/s in a reconfigurable on-chip delay-line

Area of Science:

• Photonics and optical engineering
• Integrated optics
• Waveguide technology

Background:

• Optical signal processing requires precise control over optical pulse delays.
• Coupled-resonator optical waveguides (CROWs) offer a promising platform for on-chip optical delay lines.
• Silicon oxynitride technology provides a suitable platform for fabricating high-performance optical devices.

Purpose of the Study:

• To investigate the performance of a silicon oxynitride-based coupled-resonator optical waveguide (CROW) for optical pulse delay control.
• To evaluate the signal integrity and transmission quality of delayed optical pulses.
• To assess the storage efficiency and footprint of the CROW device.

Main Methods:

• Fabrication of a CROW using directly coupled ring-resonators in 4.5%-index contrast silicon oxynitride.
• Experimental demonstration of continuous optical pulse delay control.
• Bit error rate (BER) measurements at 10 Gbit/s to assess signal quality.
• Characterization of fractional losses and storage efficiency.

Main Results:

• Error-free transmission (BER < 10(-9)) achieved at 10 Gbit/s for fractional delays up to 3 bits.
• Fractional losses remained below 1 dB per bit-delay.
• High storage efficiency exceeding 0.5 bit/RR demonstrated.
• Compact device footprint achieved (7 mm(2)).

Conclusions:

• The developed CROW enables continuous and manageable optical pulse delay with minimal signal degradation.
• The hitless reconfiguration scheme allows delay tuning without interrupting data flow.
• The device shows significant potential for optical buffering and signal processing applications.