G. de Valicourt

Low-Threshold Heterogeneously Integrated InP/SOI Lasers With a Double Adiabatic Taper Coupler

We report on a heterogeneously integrated InP/silicon-on-insulator (SOI) laser source realized through divinylsiloxane-bis-benzocyclobutene (DVS-BCB) wafer bonding. The hybrid lasers present several new features. The III-V waveguide has a width of only 1.7 μm, reducing the power consumption of the device. The silicon waveguide thickness is 400 nm, compatible with high-performance modulator designs and allowing efficient coupling to a standard 220-nm high index contrast silicon waveguide layer. In order to make the mode coupling efficient, both the III-V waveguide and silicon waveguide are tapered, with a tip width for the III-V waveguide of around 800 nm. These new features lead to good laser performance: a lasing threshold as low as 30 mA and an output power of more than 4 mW at room temperature in continuous-wave operation regime. Continuous wave lasing up to 70°C is obtained.

Network-embedded self-tuning cavity for WDM-PON transmitter

A network-embedded self-tuning cavity is proved in WDM-PON transmission over 32 channels, with two-ONU simultaneous operation and downstream signal. Performance at 1.25 Gb/s are experimentally analyzed after 25 km and 50 km SSMF.

High Gain (30 dB) and High Saturation Power (11 dBm) RSOA Devices as Colorless ONU Sources in Long-Reach Hybrid WDM/TDM-PON Architecture

We propose a hybrid wavelength-division-multi-plexing/time-division-multiplexing architecture using reflective semiconductor optical amplifiers (RSOAs) for next-generation access solutions. We demonstrate that the use of a high gain and high output power RSOA as remote modulator enables a 36-dB optical budget for colorless operation at 2.5 Gb/s over 45-km single-mode fiber. This RSOA-based configuration provides a reasonable cost per user for this hybrid system and can be easily upgraded.

A Comparison of Radio Over Fiber Link Types for the Support of Wideband Radio Channels

Three radio over fiber link types are compared to assess their relative performance for the optical transmission of next generation wireless signals having multiple wideband radio channels with high-level modulation. These links differ in their choice of modulation device; either a directly modulated laser (DML) or external modulation using a Mach-Zehnder modulator (MZM) or a reflective semiconductor optical amplifier (RSOA). The DML and RSOA link types are shown to suffer minimal degradation of the uplink wireless range compared to the baseline value without an optical link, using optimum components in terms of cost and performance. The optimum technology depends on the relative merits of simplicity (DML) or optical network architecture flexibility (RSOA).

Direct 10-Gb/s Modulation of a Single-Section RSOA in PONs With High Optical Budget

We experimentally demonstrate 10-Gb/s operation of a reflective semiconductor optical amplifier (RSOA) for data transmission in passive optical networks, with optical power budgets of up to 28 dB. Besides a passive adaptation for the electrooptical response of the semiconductor device, neither active electronic equalization nor optical offset filtering was applied to enhance the modulation bandwidth of the RSOA. Error-free transmission without using error correcting codes can be obtained even for low RSOA input power values of -20 dBm.

Radio-Over-Fiber Access Network Architecture Based on New Optimized RSOA Devices With Large Modulation Bandwidth and High Linearity

Next-generation wireless communications systems need to have high throughputs to satisfy user demand, to be low-cost, and to have an efficient management as principal features. Using a high-performance, low-cost reflective semiconductor optical amplifier (RSOA) as a colorless remote modulator at the antenna unit, the wavelength-division multiplexing (WDM) technique can be used for supporting distributed antenna systems (DASs). Each antenna unit is connected to the central unit using optical fiber and all links are used to transmit radio signals. Due to a large optical bandwidth, RSOAs are potential candidates for cost effective WDM systems. In this paper, simulations are carried out to determine optimized RSOA devices for wireless technology. New RSOA structures are fabricated and evaluated. The optimized RSOA is electrically driven by a standard Wi-Fi input signal (IEEE 802.11 g) with a 64-quadrature amplitude modulation (QAM) format. A large modulation bandwidth and a high electrooptic gain are demonstrated, which are confirmed by good performance when using orthogonal frequency-division multiplexing techniques. Characteristics such as high linearity and large electrooptic modulation bandwidth of our RSOA are sufficient to ensure an error vector magnitude (EVM) lower than 5% with a dynamic range exceeding 35 dB in a back-to-back configuration (at 0 dBm). Uplink transmission over a 20 km of single-mode fiber is also demonstrated with EVM lower than 5% and a dynamic range exceeding 25 dB (at 5 dBm).

Demonstration of a Remotely Dual-Pumped Long-Reach PON for Flexible Deployment

We propose and experimentally demonstrate a flexible wavelength division multiplexing/time division multiplexing network architecture for converged metro-access environment. Entire passiveness in the fiber plant is achieved with remote amplification in the signal distribution nodes along the metro ring and in the power splitters of the local access tree. We assist a traditional remote pumping scheme with a distributed pump provided by the optical network units and demonstrate that loss budgets beyond 30 dB can be supported. Data transmission of up to 10 Gb/s is evaluated in different deployment scenarios, reaching from a 78 km long reach rural to a dense 1:128 split/λ urban configuration with field installed fibers, including also worst case resilience configurations.

Experimental Validation of a Reflective Semiconductor Optical Amplifier Model Used as a Modulator in Radio Over Fiber Systems

We improve and validate the multisection model for a bulk reflective semiconductor optical amplifier (RSOA) as a modulator in radio over fiber (RoF) systems. The RSOA model was developed using the symbolically defined devices (SDD) component under Agilent advanced design systems (ADS) software. An accurate parameter extraction method based on ADS optimization tools is presented. The intrinsic parameters of RSOA are obtained. Here the model is used to assess the static characteristics, harmonic and intermodulation distortions, and transmission performance of RSOA. Simulations have been validated with experimental results providing good agreement.

Directly modulated and fully tunable hybrid silicon lasers for future generation of coherent colorless ONU

We propose and demonstrate asymmetric 10 Gbit/s upstream--100 Gbit/s downstream per wavelength colorless WDM/TDM PON using a novel hybrid-silicon chip integrating two tunable lasers. The first laser is directly modulated in burst mode for upstream transmission over up to 25 km of standard single mode fiber and error free transmission over 4 channels across the C-band is demonstrated. The second tunable laser is successfully used as local oscillator in a coherent receiver across the C-band simultaneously operating with the presence of 80 downstream co-channels.

Monolithic integrated silicon-based slot-blocker for packet-switched networks

We demonstrate a 16-channel, silicon-on-insulator, monolithic integrated slot-blocker. This silicon photonic circuit includes two arrayed waveguide gratings, 16 variable optical attenuators and two vertical fiber couplers. We successfully operate it with 56 Gb/s and 80 Gb/s QPSK optical packets.