Conventional Semiconductor Optical Amplifiers Research Articles

Efficiency-boosted semiconductor optical amplifiers via mode-division multiplexing

Semiconductor optical amplifiers (SOAs) are a fundamental building block for many photonic systems. However, their power inefficiency has been setting back operational cost reduction, circuit miniaturization, and the realization of more complex photonic functions such as large-scale switches and optical phased arrays. In this work, we demonstrate significant gain and efficiency enhancement using an extra degree of freedom of light—the mode space. This is done without changing the SOA’s material design, and therefore high versatility and compatibility can be obtained. Light is multiplexed in different guided modes and reinjected into the same gain section twice without introducing resonance, doubling the interaction length in a broadband manner. Up to 87% higher gain and 300% higher wall-plug efficiency are obtained in a double-pass SOA compared to a conventional single-pass SOA, at the same operating current, in the wavelength range of 1560–1580 nm.

XPoM-based 8-port photonic interconnection with low polarization sensitivity utilizing S–E–S hybridization

In this paper, we propose a hybrid amplifier-based 8-port Cross-Polarization Modulation (XPoM) interconnection with low polarization sensitivity unlike conventional Semiconductor Optical Amplifier (SOA)-based switching. The three-stage configuration utilizes Erbium-Doped Fiber Amplifier (EDFA) as an intermediate stage to reduce the effects of inherent polarization modulation creating large Transverse Electric – Transverse Magnetic (TE–TM) relative phase shifts. The appreciable error rate of [Formula: see text] and Extinction Ratio (ER) of 14.166 dB have been obtained with 100 GHz of port-spacing at different input powers. The low Polarization-Dependent Loss (PDL) of 1.0045 dB, small variations of azimuth and ellipticity with device angle in S–E–S configuration in contrast to that of SOA, adds to the superiority of the proposed model.

Temperature response of all-optical XOR logic function based on different semiconductor optical amplifiers

A critical area of research is studying the performance of semiconductor optical amplifiers (SOAs) at high temperatures. In this paper, the performance of all-optical exclusive-OR (XOR) logic gate is investigated at high operating temperatures (TOP) using different SOAs technologies such as conventional SOAs, carrier reservoir (CR)-SOAs, reflective SOAs (RSOAs), and photonic crystal (PC)-SOAs, for the first time to our knowledge. The time-dependent differential equations of SOAs, CR-SOA, RSOAs, and PC-SOAs at different operating data rates have been solved. The performance of the XOR logic gate is evaluated by calculating the quality factors and plotting the eye diagrams for each amplifier. Besides, the dependence of the key operating parameters on the TOP is examined and assessed for each scheme. The results showed that the RSOAs perform better at high temperatures than other proposed SOA technologies.

Cross-gain modulation-based photonic reservoir computing using low-power-consumption membrane SOA on Si.

We demonstrate photonic reservoir computing (RC) utilizing cross-gain modulation (XGM) in a membrane semiconductor optical amplifier (SOA) on a Si platform. The membrane SOA's features of small active volume and strong optical confinement enable low-power nonlinear operation of the reservoir, with 101-mW-scale power consumption and 102-µW-scale optical input power. The power consumption is about an order of magnitude lower than that of conventional SOAs that exhibit saturable nonlinearity. The XGM-based reservoir is configured by injecting a delayed feedback signal into the SOA from a direction opposite to the input signal. This configuration provides robust operation of the feedback circuit because of the phase insensitivity and the elimination of loop oscillation risk. The RC performance is evaluated via the information processing capacity (IPC) and a nonlinear benchmark task. It is revealed that the XGM-based reservoir performs strong nonlinear transformation of input time-series signals. The series of results consistently show that the membrane SOA performs RC-applicable nonlinear operations through XGM at a low power scale.

Theoretical investigation of 120 Gb/s all-optical AND and OR logic gates using reflective semiconductor optical amplifiers

The performance of all-optical (AO) logic AND and OR gates, which are realized for the first time using reflective semiconductor optical amplifiers (RSOAs) as nonlinear elements, is theoretically investigated at 120 Gb / s. The switching modules that incorporate the RSOAs and exploit their potential for AO signal processing are the Mach–Zehnder interferometer and the delayed interferometer for the AND and OR operations, respectively. A performance comparison between an RSOA and a conventional semiconductor optical amplifier (SOA) is made by examining and assessing the quality factor against the operational critical parameters, including the effect of the amplified spontaneous emission. The obtained results confirm that these Boolean functions based on RSOAs can be executed at the target data rate with better performance than if conventional SOAs were used instead.

Execution of all-optical Boolean OR logic using carrier reservoir semiconductor optical amplifier-assisted delayed interferometer

It is known that the conventional bulk semiconductor optical amplifier (SOA) faces the problem of the slow gain recovery time, which limits its application as a nonlinear element at higher data rates. Therefore, our goal is to find an alternative that works at higher rates with acceptable performance. In this paper, we employ, for the first time to our knowledge, a carrier reservoir SOA (CR-SOA) followed by a delayed interferometer (DI) to execute all-optically the Boolean OR operation at a data rate of 100 Gb/s. A performance comparison between the CR-SOA- and the conventional bulk SOA-based DI is made by studying the variation of the quality factor (Q-factor) against various key operating parameters, which include the transition time from the carrier reservoir to the active region, the population inversion factor, the injection current, the equivalent pseudorandom binary sequence length, the alpha-factor, the optical confinement factor, the operating data rate, the input pulse energy, and the continuous wave power in the presence of amplified spontaneous emission noise. The obtained results demonstrate that owing to the CR-SOA faster gain and phase recovery, the CR-SOA-DI is more suitable for realizing the OR logic gate at 100 Gb/s as it manages to achieve a more than acceptable Q-factor value of 9, compared to the unacceptable value of 3 when using the conventional SOA-DI.

Ultrafast carrier reservoir semiconductor optical amplifiers-based all-optical AND logic gate

It has become an imperative reality to find an alternative for the conventional bulk semiconductor optical amplifier (SOA), which suffers from the slow dynamic response, in light of the increased need for higher speeds. In this research, the carrier reservoir SOA (CR-SOA) is employed as a suitable alternative to investigate the all-optical AND logic gate for the first time at an operating speed of 100 Gb / s. For the reliability of the results, the CR-SOAs- and the conventional SOAs-based Mach–Zehnder interferometer are compared in the same operating conditions that include the effects of the amplified spontaneous emission noise and the operating temperature to obtain more realistic simulation results. The results of Wolfram Mathematica proved that the considered Boolean function is executed at 100 Gb / s with a higher quality factor when using CR-SOAs compared to SOAs, i.e., 14 versus 4.7.

Numerical study of carrier reservoir semiconductor optical amplifier-based all-optical XOR logic gate

The long carrier lifetime of the semiconductor optical amplifier (SOA) limits its operation speed and exploitation as ultrafast nonlinear switching element. Therefore, an alternative SOA with a faster carrier lifetime is desired for high speed photonic applications. In this paper, we employ the carrier reservoir SOA (CR-SOA) for the first time to demonstrate through simulations the feasibility of all-optical exclusive-OR (XOR) logic gate at 100 Gb/s. For this purpose, a pair of CR-SOAs are incorporated in a Mach-Zehnder Interferometer. The variation of the quality factor (QF) against the key operating parameters is examined for both CR-SOAs- and conventional SOAs-based XOR gate at 100 Gb/s, including the effect of amplified spontaneous emission. The results show that not only higher but also acceptable QF is obtained at 100 Gb/s only when using CR-SOAscompared to conventional bulk SOAs, i.e. QF = 18.5 versus 3.3, respectively.

All-optical OR and NOR gates using quantum-dot semiconductor optical amplifiers-assisted turbo-switched Mach-Zehnder interferometer and serially delayed interferometer at 1 Tb/s

The turbo-switch (TS) has proven to enhance the speed of the conventional semiconductor optical amplifier (SOA) up to four times better than the single SOA architecture. A novel performance of all-optical (AO) OR and NOT-OR (NOR) logic gates using TS Mach-Zehnder interferometer (TSMZI) combined with the ultrafast quantum-dot (QD) SOAs and followed by a serially delayed interferometer (DI) is numerically analyzed and investigated at 1 Tb/s. For comparison, the results have been obtained for AO OR and NOR Boolean functions using a DI after QDSOAs-based TSMZI, QDSOAs-based TSMZI, and QDSOAs-based conventional MZI. The achieved results indicate that placing a DI in series with the QDSOAs-TSMZI renders acceptable of OA OR and NOR operations at 1 Tb/s than QDSOAs-TSMZI and QDSOAs-MZI, where this achievement is not possible.

Numerical modeling of photonic crystal semiconductor optical amplifiers-based 160 Gb/s all-optical NOR and XNOR logic gates

A photonic crystal (PC) is a periodic optical nanostructure typically containing ordered arrays of holes that confine and control the motion of photons. Moreover, PC strongly modifies the dispersion relationship. The conventional semiconductor optical amplifier (SOA), on the other hand, is an attractive nonlinear element due to its strong nonlinearity, compactness, power efficiency, and integration potential with other optoelectronic devices. Thus, we combine the unique features of PC with those of SOA to numerically model ultrafast all-optical NOT-OR (NOR) and exclusive-NOR (XNOR) logic gates at 160 Gb/s. A comparison is made between PCSOAs and conventional SOAs schemes through examining the variation of the quality factor (QF) against the key operational parameters, including the effects of the amplified spontaneous emission and operating temperature, in order to obtain more realistic results. The obtained results confirm that the considered logic operations using PCSOAs are capable of operating at 160 Gb/s with higher QF than when having conventional SOAs.

Ultrafast performance of all-optical AND and OR logic operations at 160 Gb/s using photonic crystal semiconductor optical amplifier

The light confined and controlled by photonic crystals (PCs) can be exploited to enhance the performance and reduce the size of semiconductor optical amplifiers (SOAs) in which they are embedded. By incorporating PCSOAs in a Mach-Zehnder interferometer, or using a PCSOA followed by a delayed interferometer, Boolean AND and OR gates are formed, respectively, whose performance when executed all-optically (AO) is thoroughly analyzed at 160 Gb/s. For this purpose, the variation of the quality factor against the critical data signal and PCSOA operating factors is examined and assessed when the effects of amplified spontaneous emission and working temperature are included to make the simulation more realistic. The results obtained from the conducted theoretical study suggest that leveraging the PCSOAs benefits of low absorption loss, suppressed undesirable nonlinear effects, low power consumption, and high power transmission favors realizing the considered AO gates at the target data rate. Compared to conventional SOAs, PCSOAs advanced technology allows to obtain better logic performance, as quantified by the achieved higher metrics values, and to render the practical implementation of the AO gates more feasible, since the requirements for the PCSOAs structural parameters and driving conditions become more relaxed.

1 Tb/s all-optical XOR and AND gates using quantum-dot semiconductor optical amplifier-based turbo-switched Mach–Zehnder interferometer

The turbo-switch (TS) architecture conceived for speeding up the response of conventional semiconductor optical amplifiers (SOAs) is combined for the first time with the exceptional ultrafast capability of quantum-dot (QD) SOAs. The possibility of exploiting this combination in the Mach–Zehnder interferometer (MZI) for implementing fundamental all-optical (AO) XOR and AND logic gates run at 1 Tb/s is numerically investigated, assessed, and verified. The simulation results demonstrate the superiority of the QDSOA-based TS-MZI scheme over its QDSOA-based MZI counterpart, as quantified by the improved quality factor, which can be achieved under more favorable operating conditions. The outcomes of the conducted theoretical treatment can help execute AO signal processing tasks with enhanced performance while keeping pace with the perpetual increase of single-channel data rates in an efficient and affordable manner.

All-optical multistability using cross-gain modulation in quantum-dot distributed feedback semiconductor optical amplifier

We propose and theoretically demonstrate a novel type of all-optical multistable device using single quantum dot distributed feedback semiconductor optical amplifier. The device utilizes cross-gain modulation with proper wavelength detuning to obtain multistability in a conventional DFB semiconductor optical amplifier. We find that dual bistability, which can be adjusted vertically or horizontally by applying small probe input, can be obtained in both the pump and the probe characteristics. Adjustable switching with contrast ratio as high as 14 dB is obtained from the probe signal.

Semiconductor optical amplifier direct modulation with double-stage birefringent fiber loop

The feasibility of cascading two birefringent fiber loops (BFLs) for directly modulating a conventional semiconductor optical amplifier (SOA) at a faster data rate than that being possible by its limited electrical bandwidth is demonstrated for the first time. The experimental results reveal the improvements in the quality characteristics of the encoded signal compared to those achieved with a single-stage BFL. The observed trends are complemented by numerical simulations, which allow to investigate the impact of the double-stage BFL detuning and specify how this critical parameter must be selected for enhanced performance. Provided that it is properly tailored, the proposed optical notch filtering scheme efficiently compensates for the pattern-dependent SOA response and enables this element to be employed as intensity modulator with improved performance at enhanced data speeds.

Heterogeneous gigabit orthogonal frequency division multiplexing/radio over fiber transmissions of wired and wireless signals using a reflective semiconductor optical amplifier and single‐arm mach–zehnder modulator

AbstractWe propose and experimentally demonstrate a novel radio over fiber system that provides different gigabit orthogonal frequency division multiplexing (OFDM) signals transmission for wired and wireless networks using a conventional reflective semiconductor optical amplifier and a single‐arm Mach–Zehnder modulator (MZM). To halve sampling speed of electronics and to simplify a radio frequency front‐end design, the proposed scheme adopts Hermitian symmetry to generate the wireless signal. It was reported that using the proposed scheme, 5‐Gbps 16‐quadrature‐amplitude‐modulation‐OFDM wired and 1.17‐Gbps quadrature phase‐shift keying OFDM wireless signals were successfully transmitted through 23‐km standard single mode fiber link. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1954–1958, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26968

Repetition rate and wavelength-tunable all-optical actively mode-locked fibre ring laser based on a reflective semi-conductor optical amplifier

A repetition rate- and wavelength-tunable fibre ring laser that utilises a reflective semi-conductor optical amplifier as both a gain and mode-locking element is presented. Moreover, 10.3 ps pulses at 10 GHz repetition rate are obtained across a 30 nm tuning range covering the entire C-band. The repetition rate is tunable up to 30 GHz via rational harmonic mode-locking. A comparison is made using a conventional semi-conductor optical amplifier as the gain and mode-locking element. It is shown that the reflective semi-conductor optical amplifier requires in excess of 5 dB less average pump pulse power in order to achieve the optimum mode-locking condition, for achieving the narrowest output pulse width, thereby relaxing the requirement for a complex and expensive pump pulse source.

The Dynamic Gain Modulation Performance of Adjustable Gain-Clamped Semiconductor Optical Amplifiers (AGC-SOA)

The growth in demand for high bandwidth services has stimulated the deployment of Passive Optical Networks (PONs), directly to the home or to the kerb. In many cases, particularly extended reach PONs which may cover distances of 100 km or more [1], there is the need for low cost reach extension technologies. Semiconductor Optical Amplifiers (SOAs) have a key role in this context, particularly because upstream traffic is commonly carried at 1.3 μm. Upstream traffic in a PON (from the Optical Network Unit, ONU to the Optical Line Terminal, OLT) is normally Time Division Multiplexed (TDM) with a wide variation in path loss arising from differences in transmission distances and splitting losses. The bursty nature of this traffic combined with a wide dynamic range of signal strength ( -15 dBm to -28 dBm-the difference between a very close ONU with a small split ratio and a distant ONU with a high split ratio), places severe demands on the burst mode receiver at the OLT. Conventional fibre amplifiers cannot adjust their gain with packet to packet variations due to their response time. Similarly, conventional SOAs suffer loss of linearity if their bias current and hence gain is rapidly reduced. The paper reports on an adjustable gain-clamped semiconductor optical amplifier (AGC-SOA) designed to maximize the output saturated power while adjusting gain to regulate power differences between packets without loss of linearity. Theoretical modeling predicts that this device is able to modulate gain at nanosecond rates. The analysis is validated experimentally.

Quantum-Dot Semiconductor Mode-Locked Lasers and Amplifiers at 40 GHz

Mode-locked lasers (MLLs) and semiconductor optical amplifiers (SOAs) based on quantum-dot (QD) gain material will impact the development of next-generation networks, such as the 100 Gb/s Ethernet. MLLs presently consisting of a monolithic two-section device already generate picosecond pulse trains at 40 GHz. Temperature dependence of pulsewidth for p-doped devices, a detailed chirp analysis that is a prerequisite for optical time-division multiplexing applications, and data transmission experiments are presented in this paper. QD SOAs show superior performance for linear amplification as well as nonlinear signal processing. Using cross-gain modulation for wavelength conversion, QD SOAs are shown to have a small signal bandwidth beyond 40 GHz under high-bias current injection. This makes QD SOAs much superior to conventional SOAs.

Broadband Wavelength-swept Raman Laser for Fourier-domain Mode Locked Swept-source OCT

A novel broadband wavelength-swept Raman laser was used to implement Fourier-domain mode locked (FDML) swept-source optical coherence tomography (SS-OCT). Instead of a conventional semiconductor optical amplifier, this study used broadband optical fiber Raman amplification, over 50 nm centered around 1545 nm, using a multi-wavelength optical pumping scheme, which was implemented with the four laser diodes at the center wavelengths of 1425, 1435, 1455 and 1465 nm, respectively, and the maximum operating power of 150 mW each. The operating swept frequency of the laser was determined to 16.7 kHz from the FDML condition of 12 km optical fiber in the ring cavity. The OCT images were obtained using the novel broadband wavelengthswept Raman laser source.

반도체 광 증폭기 XOR 논리게이트를 이용한 10 Gbps 전광 암호화 시스템의 구현

전자 논리회로에서 이용되는 전자신호 암호화와 같은 방법으로, 반도체 광 증폭기 XOR논리 게이트를 이용한 전광 암호화 시스템을 제안하였다. 시스템의 변수를 최적화 하고 전체 디자인 과정을 빠르게 수행하기 위해 정상상태와(steady state) 과도상태에(dynamic) 대한 전산모사가 차례로 이루어졌다. 심각한 신호 왜곡이 없이 10 Gbps 속도에서 일반적인 반도체 광 증폭기의 연속적 연결을 통해 전광 신호에 대한 암호화와 해독이 수행될 수 있음을 전산모사와 실험에 의한 결과를 통해 보여주었다. An all-optical encryption system built on the basis of electrical logic circuit design principles is proposed, using semiconductor optical amplifier (SOA) exclusive or (XOR) logic gates. Numerical techniques (steady-state and dynamic) were employed in a sequential manner to optimize the system parameters, speeding up the overall design process. The results from both numerical and experimental testbeds show that the encoding/decoding of the optical signal can be achieved at a 10 Gbps data rate with a conventional SOA cascade without serious degradation in the data quality.