Jean-Guy Provost

1.55 /spl mu/m polarisation independent semiconductor optical amplifier with 25 dB fiber to fiber gain

Using a tapered in width square active waveguide and bulk InGaAsP/InP material we demonstrate a polarisation independent amplifier structure operating at 1550 nm with a reduced far-field divergence. Improvement of coupling efficiency enables us to achieve a 25 dB fiber to fiber gain together with 9 dBm fiber saturation output power for 150 mA bias current. A 200 ps gain recovery time allows fast gating or wavelength conversion.<<ETX>>

Measuring the Chirp and the Linewidth Enhancement Factor of Optoelectronic Devices with a Mach–Zehnder Interferometer

In this paper, a technique based on the use of a Mach-Zehnder (MZ) interferometer is proposed to evaluate chirp properties, as well as the linewidth enhancement factor (αH-factor) of optoelectronic devices. When the device is modulated, this experimental setup allows the extraction of the components response of amplitude modulation (AM) and frequency modulation (FM) that can be used to obtain the value of the αH-factor. As compared with other techniques, the proposed method gives also the sign of the αH-factor without requiring any fitting parameters and, thus, is a reliable tool, which can be used for the characterization of high-speed properties of semiconductor diode lasers and electroabsorption modulators. A comparison with the widely accepted fiber transfer function method is also performed with very good agreement.

InP-Based Photonic Multiwavelength Transmitter With DBR Laser Array

We demonstrate an InP-based photonic multiwavelength transmitter realized by integrating an array of distributed Bragg reflector lasers with modulators in Mach-Zehnder configuration. An arrayed waveguide grating is used to multiplex the generated signals into a common optical output. The device is designed according to a generic integration concept, using standardized building blocks, and is fabricated in a multiproject wafer run. The device delivers up to 4 dBm of optical power into the fiber with a modulation data rate of 12.5 Gbps per transmission channel. The obtained performance makes it very promising for application in the next generation optical access networks as a key source in the central office part of the telecommunication systems.

Phase correlation between longitudinal modes in semiconductor self-pulsating DBR lasers

Phase correlation leading to self-pulsation (SP) in semiconductor distributed Bragg reflector (DBR) lasers is investigated experimentally and theoretically. Under proper biasing conditions, the laser oscillates with three main modes and we observe that each two-modes beating provides SP with identical spectral linewidth. Under the same operating conditions, the measured spectral linewidths of the beating modes are much larger than the linewidth of the self-pulsating signal. These results demonstrate the natural occurrence of passive mode-locking (PML) and phase correlation in semiconductor DBR lasers. A model based on multimode coupled-wave rate equations, including four-wave mixing (FWM), is developed to describe PML and SP in the gain region of the laser cavity. This model demonstrates that the existence of phase correlation between longitudinal modes is due to FWM.

Dynamic properties of InAs∕InP (311)B quantum dot Fabry–Perot lasers emitting at 1.52μm

Dynamic properties of truly three-dimensional-confined InAs∕InP quantum dot (QD) lasers obtained by molecular beam epitaxy growth on a (311)B oriented substrate are reported. The relative intensity noise and small signal modulation bandwidth experiments evidence maximum relaxation frequency of 3.8GHz with a clear relaxation oscillation peak, indicating less damping than InAs∕GaAs QD lasers. The Henry factor amounts to ∼1.8 below threshold and increases to ∼6 above threshold, which is attributed to band filling of the thick wetting layer.

New integrated buried laser-ridge modulator with identical active layer

Integrated laser modulators are attractive devices for wavelength-division-multiplexing optical systems due to their compactness, high output power, and low cost. Their fabrication simplicity is a way to decrease further the transmitter cost and address new opening markets of short range and metropolitan networks. We report a new integration scheme electroabsorption-modulator distributed feedback (DFB) laser based on well-established industrial solutions for discrete buried ridge (BRS) DFB lasers and discrete shallow ridge modulators. Processing simplification with an identical active layer has been possible due to a good behavior of strongly positively detuned BRS lasers. The integrated devices demonstrated 30-dB extinction ratio with 10-GHz bandwidth and P/sub out/=10 dBm for emission in 1.55-/spl mu/m range.

Self-injected semiconductor distributed feedback lasers for frequency chirp stabilization

It is well known that semiconductor distributed feedback lasers (DFB) are key devices for optical communications. However direct modulation applications are limited by the frequency chirp induced by current modulation. We demonstrate that a proper external control laser operation leads to chirp-to-power ratio (CPR) stabilization over a wide range of modulation frequencies as compared to the free-running case. Under experimentally selected optical feedback conditions, the CPR decreases significantly in the adiabatic regime from about 650 MHz/mW in the solitary case down to 65 MHz/mW. Experimental results are also confirmed by numerical investigations based on the transfer matrix method. Simulations point out the possible optimization of the CPR in the adiabatic regime by considering a judicious cavity design in conjunction with a proper external control. These results demonstrate important routes for improving the transmission performance in optical telecommunication systems.

The Dual-Electroabsorption Modulated Laser, a Flexible Solution for Amplified and Dispersion Uncompensated Networks Over Standard Fiber

We propose here a monolithically integrated dual RF access electroabsorption-modulated laser called D-EML for the generation of optical single-sideband signal for both nonreturn to zero and orthogonal frequency division multiplexing formats. The benefits of optical single-sideband over double sideband in terms of resilience against chromatic dispersion effects are presented for high-bit rate intensity modulation/direct detection transmissions over standard single mode fiber in the C-band. Both simulation and experimentation exhibit transmission distance enhancement in the case of dual modulation of the D-EML, i.e., in optical single-sideband configuration, making this optical source an interesting solution because of its low-cost, low-size, and reasonable-power consumption.

12.5GB operation of a novel monolithic 1.55µm BPSK source based on prefixed optical phase switching

Novel optical phase switching BPSK transmitter was used to transmit 12.5GB signal over 40km. Speed scalability, ultra-small footprint and low power drive of the monolithic circuit are attractive for advanced format migration towards low-cost applications.

10 Gbit/s drop and continue colorless operation of a 1.5μm AlGalnAs reflective amplified electroabsorption modulator

AlGalnAs large spectral range EAM has been integrated with SOA using Single Active Layer technology. The device operates as a 10Gbit/s drop & continue colorless element in a 50nm spectral range up 60°C