Increased sensitivity through maximizing the extinction ratio of SOI delay-interferometer receiver for 10G DPSK.

We present an optimized design for a 10G- differential-phase-shift-keyed (DPSK) receiver based on a silicon-on-insulator (SOI) unbalanced tunable Mach-Zehnder interferometer (MZI) switch in sequence with a Mach-Zehnder delay interferometer (MZDI). The proposed design eliminates the limitation in sensitivity of the device produced by the waveguide propagation losses in the delay line. A 2.3 dB increase in receiver sensitivity at a bit-error-rate (BER) of 10(-9) is experimentally measured over a standard implementation. The enhanced sensitivity is achieved with zero power consumption by tuning the operating wavelength or with less than 5 mW for a fixed wavelength using microheaters. Also the foot-print of the device is minimized to 0.11 mm(2) by the use of compact spirals.

High-contrast 40 Gb/s operation of a 500 µm long silicon carrier-depletion slow wave modulator.

In this Letter, we demonstrate a highly efficient, compact, high-contrast and low-loss silicon slow wave modulator based on a traveling-wave Mach-Zehnder interferometer with two 500 µm long slow wave phase shifters. 40 Gb/s operation with 6.6 dB extinction ratio at quadrature and with an on-chip insertion loss of only 6 dB is shown. These results confirm the benefits of slow light as a means to enhance the performance of silicon modulators based on the plasma dispersion effect.

Silicon slow-light-based photonic mixer for microwave-frequency conversion applications.

We describe and demonstrate experimentally a method for photonic mixing of microwave signals by using a silicon electro-optical Mach-Zehnder modulator enhanced via slow-light propagation. Slow light with a group index of ~11, achieved in a one-dimensional periodic structure, is exploited to improve the upconversion performance of an input frequency signal from 1 to 10.25 GHz. A minimum transmission point is used to successfully demonstrate the upconversion with very low conversion losses of ~7 dB and excellent quality of the received I/Q modulated QPSK signal with an optimum EVM of ~8%.

High speed silicon electro-optical modulators enhanced via slow light propagation.

While current optical communication networks efficiently carry and process huge amounts of digital information over large and medium distances, silicon photonics technology has the capacity to meet the ceaselessly increasing demand for bandwidth via energy efficient, inexpensive and mass producible short range optical interconnects. In this context, handling electrical-to-optical data conversion through compact and high speed electro-optical modulators is of paramount importance. To tackle these challenges, we combine the attractive properties of slow light propagation in a nanostructured periodic waveguide together with a high speed semiconductor pn diode, and demonstrate a highly efficient and mass manufacturable 500 µm-long silicon electro-optical device, exhibiting error free modulation up to 20 Gbit/s. These results, supported by modulation rate capabilities reaching 40 Gbit/s, pave a foreseeable way towards dense, low power and ultra fast integrated networks-on-chip for future chip-scale high performance computing systems.

Strong electro-optical modulation enhancement in a slow wave corrugated waveguide.

We modelled strong slow wave modulation enhancement in a rib corrugated waveguide with respect to a conventional rib waveguide, both embedded in a reverse biased pn junction. This enhancement is characterized in terms of effective index change versus reverse bias variations from 0V to -10V and for moderate group velocities varying in the range 0.02c to 0.15c. Interaction lengths and insertion losses below 750 microm and 3dB are respectively found for voltage variations in the range -8V to -10V. Furthermore, the device electrical modulation bandwidth is expected to be higher than 10 GHz.

High-speed modulation of a compact silicon ring resonator based on a reverse-biased pn diode.

High speed modulation based on a compact silicon ring resonator operating in depletion mode is demonstrated. The device exhibits an electrical small signal bandwidth of 19 GHz. The device is therefore a candidate for highly compact, wide bandwidth modulators for a variety of applications.