Traveling-wave Semiconductor Laser Amplifier Research Articles

A simple spice model for traveling wave semiconductor laser amplifier

AbstractAn equivalent lumped element electric circuit model for traveling wave semiconductor laser amplifier has been developed using the rate equation for carriers. SPICE simulation of the circuits gives results in close agreement with the experimental data and values from sophisticated analyses. The modulation bandwidth and transient response were examined by including parasitic elements in the intrinsic model. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1558–1561, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22483

Cross-talk analysis of optical time-division demultiplexer

We have developed a simulation model to investigate the demultiplexing of all-optical-time-division-multiplexed data, employing an optical time-division demultiplexer. Particular attention is paid to the cross-talk performance when selected parameters of the system are varied. The system used to demultiplex the data is the asymmetric semiconductor laser amplifier loop mirror (ASLALOM), which is capable of selecting high-speed optical pulses within a data train. The authors use a model of the ASLALOM that includes a time and space analysis of a traveling-wave semiconductor laser amplifier. Our investigation shows that this system produces cross talk that is dependent on the data rate, control pulse energy, and control pulse rate.

Circuit model for traveling wave semiconductor laser amplifiers

A circuit model of a traveling wave semiconductor laser amplifier is presented for the circuit level simulation of single device or Optoelectronics Integrated Circuit (OEIC) included amplifiers. To verify the model, the simulated results are compared with the experimental results.

A novel analytical expression of saturation intensity of InGaAsP tapered traveling-wave semiconductor laser amplifier structures

We have proposed a novel approximate analytical expression for saturation intensity for tapered traveling-wave semiconductor laser amplifier structures. The application of this analytical expression of saturation intensity has been demonstrated by considering the effect of gain saturation on polarization sensitivity of two tapered amplifier structures, linear and exponential tapered amplifier structures. It is found that polarization sensitivity of the tapered amplifier structure is several decibels higher than that of passive tapered waveguides in unsaturated condition. Polarization sensitivity of the two tapered amplifier structures has also been investigated in a highly saturated condition. The combined effects of mode conversion and gain saturation on fundamental TE gain have also been investigated using the proposed analytical expression for saturation intensity.

Analytic theory of coherent cross-gain modulation in semiconductor travelling-wave amplifiers

Abstract We report a simple analytic solution to the problem of cross amplitude-phase modulation in nonlinear two-wave mixing, under the approximation of constant saturating power. The results are applied to travelling-wave semiconductor laser amplifiers where the linewidth enhancement factor inevitably leads to amplitude-phase coupling and asymmetric energy transfer. Our solution is used to obtain the transmission gain of each beam, the spectral profile and the amplifier input-output characteristics. Limits are established as to the applicability of the analytic solution, by comparison with numerical solutions to the related full four-wave mixing problem.

Analytic theory of coherent cross-gain modulation in semiconductor travelling-wave amplifiers

We report a simple analytic solution to the problem of cross amplitude-phase modulation in nonlinear two-wave mixing, under the approximation of constant saturating power. The results are applied to travelling-wave semiconductor laser amplifiers where the linewidth enhancement factor inevitably leads to amplitude-phase coupling and asymmetric energy transfer. Our solution is used to obtain the transmission gain of each beam, the spectral profile and the amplifier input-output characteristics. Limits are established as to the applicability of the analytic solution, by comparison with numerical solutions to the related full four-wave mixing problem.

All-optical time-division-multiplexing of 100 Gbit/s signal based on four-wave mixing in a travelling-wave semiconductor laser amplifier

All-optical time-division multiplexing is experimentally demonstrated using four-wave mixing in a semiconductor laser amplifier. A 100 GHz, 1.562 /spl mu/m signal is modified by 10 Gbit/s signals to generate 1.552 /spl mu/m subchannels in a 100 Gbit/s signal and its error free operation is confirmed.

Meeting the need for fiber-optic transmission speed

Review current OTDMA technology, with the emphasis on optical clock recovery and time demultiplexing. Various optical switching techniques are surveyed, and they are compared by taking account of the potential feasibility of engineering implementation. The architectures for OTDMA networks are described, and we look at all-optical clock recovery schemes that are based on traveling-wave (TW) semiconductor laser amplifiers, self-pulsating laser diodes, EO switches, mode locking of a fiber ring laser, and four-wave mixing (FWM). We also review various optical switching techniques for ultrafast time demultiplexing.

Frequency conversion in travelling wave semiconductor laser amplifiers with bulk and quantum well structures

A microscopic model of four-wave mixing in semiconductor materials is applied to the analysis of bulk and multiple quantum well travelling wave amplifiers. The nonlinear optical response includes, in the framework of the density matrix formalism, the main four-wave mixing processes for frequency detuning of the input optical fields up to the THz region. A typical pump and probe configuration is considered, where a strong pump at angular frequency ωpump with a weaker probe ωprobe is injected at the input; at the output a new signal appears with ωsignal = 2ωpump – ωprobe. Particular emphasis is given to the comparison and the optimisation of frequency conversion in bulk and quantum well amplifiers. In optimised devices, the numerical results show good conversion performances in the two kinds of structures, even if quantum well amplifiers give higher conversion gains.

Polarisation-independent all-optical demultiplexing up to 200 Gbit/s using four-wave mixing in a semiconductor laser amplifier

Polarisation-independent all-optical time-division demultiplexing is demonstrated up to 200 Gbit/s with <0.5 dB polarisation dependency based on four-wave mixing in depolarised TE and TM modes in a travelling-wave semiconductor laser amplifier.

Traveling‐wave semiconductor laser amplifier induced intermodulation distortion for different digital modulation schemes in a subcarrier multiplexing system

AbstractWe analyze the intermodulation distcrtion (IMD) induced by four‐wave mixing in traveling‐wave semiconductor laser amplifiers (TWSLA) for different digital modulation schemes in a subcarrier multiplexing (SCM) system, and compare these results with the transmission of pure tones. We find that the IMDs are reduced in the digital modulation system, because the modulated signals disturb the homogeneous property of amplitude (ASK, FSK) or phase (PSK). We conclude that PSK has better performance, and the worst case is the transmission of pure tones. © 1995 John Wiley & Sons, Inc.

Small-signal analysis of wavelength conversion in semiconductor laser amplifiers via gain saturation

Wavelength conversion due to gain saturation in a travelling wave semiconductor laser amplifier is analyzed using a small-signal model. An analytic expression is developed showing that the small-signal bandwidth of wavelength conversion is not limited simply to the carrier modulation bandwidth, but also depends on the single-pass gain of the device.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Two-section traveling-wave semiconductor laser amplifier optically transparent time-division multiplexed channel selector

A two-section traveling-wave semiconductor laser amplifier can be utilized as a time-division demultiplexer or channel selector in all-optical networks. Light injected into the amplifier causes changes in the carrier density, which manifests itself as a change in the amplifier electrode voltages that can be processed to obtain the original data signal. Numerical analysis shows that by suitable choice of the electrode bias currents responsitivity and speed are optimized while system transparency is maintained. With optimal device design, demultiplexing speeds of the order of several gigabits per second are feasible.

All-optical phase modulation in a traveling wave semiconductor laser amplifier

A novel all-optical phase modulation and wavelength conversion has been demonstrated in a traveling wave semiconductor laser amplifier. Even though the optical gain modulation caused by the saturation effect in a traveling wave semiconductor laser amplifier is sensitive to the signal wavelength, the optically controlled phase modulation is relatively independent of the signal wavelength. >

Demultiplexing using polarisation rotation in a semiconductor laser amplifier

An all-optical demultiplexing operation has been performed using polarisation rotation due to nonlinear effects in a travelling wave semiconductor laser amplifier. A 10 Gbit/s channel can be extracted from a 20 Gbit/s data stream using this technique.

20 Gbit/s wavelength conversion using semiconductor nonlinearity

A polarisation insensitive wavelength conversion of 20 Gbit/s data signals over a range of 12 nm has been demonstrated using nonlinear processes (cross-phase modulation) in a travelling wave semiconductor laser amplifier and a polarisation nulling technique.

Analysis of the all-electrical automatic gain control of travelling-wave semiconductor laser amplifiers

The all-electric automatic gain control of a travelling wave semiconductor laser amplifier through the error signal detected from its junction voltage is analysed. Three different control schemes are compared. The ability to suppress the optical gain variation caused by the polarisation fluctuation is particularly addressed.

20 Gbit/s all-optical clock recovery using semiconductor nonlinearity

All-optical clock recovery at bit rates up to 20 Gbit/s has been demonstrated using an erbium-doped fibre ring laser with an all-optical active modelocking element consisting of a travelling wave semiconductor laser amplifier. The recovered clock pulses are suitable for use in ultrafast synchronisation systems.

Modelocked ring laser using nonlinearity in a semiconductor laser amplifier

Trains of picosecond pulses at 10 and 20GHz have been generated from a erbium-doped fibre ring laser with an all-optical active modelocking element consisting of a travelling wave semiconductor laser amplifier. The repetition rate of the laser is variable because it is dependent on the frequency of an injected optical pulse train.

Deformation of signal in nearly degenerate four-wave mixing with travelling-wave semiconductor laser amplifiers

A theoretical analysis is given to demonstrate the behavior of the deformation of a signal in nearly degenerate four-wave mixing with travelling-wave semiconductor laser amplifiers.