Semiconductor Optical Amplifier Structure Research Articles

Design of dual semiconductor optical amplifier structure based all-optical standard quaternary inverter and quaternary clocked SR flip-flop

Design of dual semiconductor optical amplifier structure based all-optical standard quaternary inverter and quaternary clocked SR flip-flop

All-optical noise reduction of fiber laser via intracavity SOA structure.

We have designed a unique intracavity semiconductor optical amplifier (SOA) structure to suppress the relative intensity noise (RIN) for a fiber DFB laser. By exploiting the gain saturation effect of the SOA, a maximum noise suppression of 30 dB around the relaxation oscillation frequency is achieved, and the whole resonance relaxation oscillation peak completely disappears. Moreover, via a specially designed intracavity SOA structure, the optical intensity inside the SOA will be in a balanced state via the oscillation in the laser cavity, and the frequency noise of the laser will not be degraded with the SOA.

Terahertz radiation shaping based on optical spectrum modulation in the time domain

A terahertz shaping system based on optical fiber components as opposed to traditional free-space solutions is proposed. It is based on the time-domain modulation of the optical source spectrum. Standard single-mode fiber distributes and disperses the pulse before filtering its spectral components by means of the cross-gain and cross-phase modulation effects taking place in an interferometric semiconductor optical amplifier structure. Experimental measurements are obtained, showing the tunability of the system as well as its reconfigurability.

All-Optical Signal Processing by Using SOA Nonlinearities: Prospects for the Evolution of Next Generation of Optical Networks

This article focuses on the realization of all-optical signal processing functions based on the nonlinearities of a semiconductor optical amplifier (SOA) by reviewing the recent and significant patents and publications related to these new developments and applications. One of the main contributions of this paper is to highlight the feasibility of experimental implementation of three logic gates: NAND, OR, and NOR optical gates by exploiting the nonlinear polarization rotation in a SOA structure without changing the setup configuration. Switching between each optical function is done by only adjusting the input optical power level. The experimental investigation is done in free space, allowing optimum control and preservation of the polarization state of the injected and collected signals.

All-optical clocked D flip-flop memory using a hybrid integrated S-R latch

We demonstrate, by using multiple Mach-Zehnder interferometer (MZI)-semiconductor optical amplifier structures, an all-optical synchronous D type flip-flop, with high-photonic integration capability. Experimental performance analysis shows its functional and performance feasibility and high-switching speeds were achieved. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1201–1204, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25998

Boost up of four wave mixing signal in semiconductor optical amplifier for 40 Gb/s optical frequency conversion

The 40Gb/s optical frequency converter for non-return to zero differential phase shift keying (NRZ-DPSK) signal by using four wave mixing in semiconductor optical amplifier (SOA) have achieved sucessfully. The optimized signal-to-pump ratio for NRZ-DPSK by using optimized SOA structure with enhanced FWM effect is also evaluated. The optimum signal-to-pump ratio is 12dB and 10dB with Q factor penalty of 0.685dB and 0.663dB. The dependence of four wave mixing efficiency and converted signal power on signal input power is studied and it is evaluated that four wave mixing efficiency decreases with increase in the input power. The impact of pump power, signal-to-pump ratio, and SOA parameters with Q factor penalty for 40Gb/s has been illustrated. It has shown that converted signal power increases up to the saturation power of semiconductor optical amplifier, then decreases. It is observed that for the optimum pump power, OSNR of converted signal varies little with signal input power.

Analysis and minimization of cross phase modulation in semiconductor optical amplifiers for multichannel WDM optical communication systems

A theoretical model for crosstalk in multichannel wavelength division multiplexing communication systems due to cross phase saturation in semiconductor optical amplifier structure is developed. This theoretical model is used to analyze the impact of the cross phase noise on the performance of semiconductor optical amplifiers in saturation region for WDM communication system by using differential phase shift modulation format. It is shown that by increasing the carrier life time, width and thickness while reducing the confinement factor, differential gain and bias current in the SOA structure mitigates the cross talk due to cross phase saturation. The impact of penalty and cross phase noise imposed on multichannel WDM links have been investigated for different parameters of the SOA with the variation in transmission distance. With the slight increase in differential gain of 200.2 × 10 −18 cm 2 and confinement factor 0.41, the maximum transmission distance observed is 5220 km with good quality and nil power penalty for 10 × 40 Gb/s soliton RZ-DPSK WDM signals for the first time.

Operational Design on High-Speed Semiconductor Optical Amplifier With Assist Light for Application to Wavelength Converters Using Cross-Phase Modulation

Using the newly developed time-dependent transfer matrix method with nonlinear effects, we analyzed the characteristics of cross-phase modulation (XPM), cross-gain modulation and gain recovery time of a semiconductor optical amplifier (SOA) with an assist light injection, which is introduced to speed up the gain recovery of the SOA. Particularly for the application to high-speed wavelength converters using XPM with an interferometer structure where /spl pi/-phase change is required, various parameters such as SOA lengths, wavelengths and powers of injected lights, and their propagation directions are designed via numerical simulation. Discussions concerning the conditions of an SOA structure and the parameters of injected lights for high-speed operation are described to show the potential of fast gain recovery with a response time as low as 25 ps.

New electrolytes for n-type InP and electrochemical C - V profiling of a semiconductor optical amplifier device structure

New electrolyte systems for profiling n-type indium phosphide (InP) have been reported and are compared with the conventional HCl electrolyte. Among the new electrolytes, the electrolyte comprising HNO3-HF-H2O has better characteristics and is best suited for profiling InP material. Both epitaxial layers and substrate materials have been subjected to electrochemical carrier concentration profiling using the new electrolyte and the estimated concentration values are compared with that of Hall effect measurements. Barrier heights of the new electrolytes have been calculated. For the first time, the dopant profiling of a complete device structure grown by the chemical beam epitaxy technique for the realization of laser and semiconductor optical amplifier structures has been presented.

1.3-μm polarization-insensitive optical amplifier structure based on coupled quantum wells

We show that polarization-insensitive optical gain over a wide bandwidth can be realized in a coupled pseudomorphic multiple-quantum-well structure. The barrier width is chosen such that heavy-hole subbands are grouped tightly and light-hole subbands are widely separated in energy. For specific strain conditions, the uppermost valence subbands, which have large occupation probability and strongly contribute to the gain, consist of a single light-hole subband and a group of coupled heavy-hole subbands. This arrangement gives rise to balanced gains for the TE and TM polarizations. We present calculated results for 1.3-/spl mu/m semiconductor optical amplifier structures based on bands calculated in the framework of an eight-band k/spl middot/p model. Two different material systems are examined, InAlGaAs and GaInAsP, on InP substrates.

Tunable wavelength filters based on nonlinear optical interactions in semiconductor amplifiers

A novel class of narrow-band tunable wavelength filters is proposed and evaluated. Wavelength selectivity of the proposed filters Is derived from the finite time response of an optical nonlinearity. The nonlinearity is gain saturation in semiconductor optical amplifier structures. The filters are shown to have very narrow passbands tunable over the entire semiconductor gain bandwidth. The key to filter implementation is a device configuration in which the wave-mixing products can be isolated from the amplified inputs. Three integrated optics compatible configurations are considered and shown to have high filter throughputs 34 to 180% and subangstrom bandwidths.