Saturated Output Power Levels Research Articles

New SOA Design With Large Gain, Small Noise Figure, and High Saturation Output Power Level

New SOA Design With Large Gain, Small Noise Figure, and High Saturation Output Power Level

A 4–32 GHz SiGe Multi-Octave Power Amplifier With 20 dBm Peak Power, 18.6 dB Peak Gain and 156% Power Fractional Bandwidth

This letter presents the design and characterization results of a multi-octave power amplifier (MOPA) fabricated in a 0.13- $\mu \text{m}$ SiGe-BiCMOS technology. The single-stage power amplifier is implemented as the stack of a cascode amplifier combining broadband input matching network with resistive feedback, and a common-base amplifier with base capacitive feedback. Measurement results show that the design delivers a peak saturated output power level of 20.2 dBm, with output of 1 dB compression at 19.4 dBm. The measured 3-dB power bandwidth is from 4 to 32 GHz, covering three octaves. The corresponding power fractional bandwidth (PFBW) is 156%. The measured peak power added efficiency is 20.6%, and peak small-signal gain is 18.6 dB. The fabricated integrated circuit occupies an area of 0.71 mm2. To compare state-of-the-art MOPAs, the power amplifier figure of merit defined by the international technology roadmap for semiconductors (ITRS) is modified to include PFBW and area. To the best of authors’ knowledge, the presented design achieves the highest figure of merit among multi-octave PAs in a silicon-based integrated circuit technology reported in the literature.

Study of Nonlinear Optical Properties of Disperse Yellow – 7 Dye-doped Polymer Films using CW Laser

The materials with an ability of self-focusing/defocusing through their light intensitydependent refractive index and phase shift properties are potential candidates for all-optical photonic devices. Several organic materials including dye-doped polymer films are attracting many researchers due to their advantages in terms of enhanced efficiency, and acceptable mechanical properties to fabricate useful devices. In this paper, we have reported the nonlinear optical properties like nonlinear absorption and nonlinear refraction of an organic dye Disperse Yellow - 7 (DY-7) doped in Polymethyl methacrylate-methacrylic acid (PMMA-MA) polymer matrix using open aperture and closed aperture Z-scan experimental methods by means of low power continuous wave (CW) laser beam. The optical limiting properties of these films are also studied using Type 1 and Type 2 configurations at different input powers using continuous wave (CW) laser beams of 532 nm wavelength. The nonlinear refractive index n2, nonlinear absorption coefficient β, changes in refractive index with input intensity, and the magnitude of third-order optical nonlinearity of the dye-doped film are experimentally determined. The sample is tested for optical power limiting in which the input limiting threshold and saturated output power level for both type 1 and type 2 optical limiting configurations are recorded. DY-7 dye-doped in PMMA-MA polymer film has shown saturation absorption at lower input irradiance and reverse saturation absorption at higher input irradiance along with thermal nonlinearity and hence found to be a potential candidate for the third harmonic property based photonic devices.

Study of Third Order Optical Nonlinearity in Disperse Orange-25 Dye-doped Polymer Films using CW Laser

The organic materials with the ability of self-focussing/defocusing through their light intensity-dependent refractive index and phase shift properties are potential materials in alloptical photonic devices have become interesting topic of continuous research. Several organic materials including dye-doped polymer films are attracting many researchers due to their advantages in terms of enhanced efficiency, and acceptable mechanical properties tofabricate useful devices. In this paper, we have reported the nonlinear optical properties like nonlinear absorption and nonlinear refraction of an organic dye Disperse Orange-25 (DO-25) doped in Polymethyl methacrylate-methacrylic acid (PMMA-MA) polymer matrix usingopen aperture and closed aperture Z-scan experimental methods by means of low power continuous wave (CW) laser beam. The optical limiting properties of these films are also studied using Type 1 and Type 2 configurations at different input powers using continuous wave (CW) laser beams of 532 nm wavelength. The nonlinear refractive index n2, nonlinear absorption coefficient β, changes in refractive index with input intensity, and the magnitude of third-order optical nonlinearity of the dye-doped film are experimentally determined. The saturated output power for type 1 and type 2 optical limiting are determined. The inputlimiting threshold and saturated output power level for both type 1 and type 2 optical limiting configurations are recorded. DO-25 dye-doped in PMMA-MA polymer film has shown saturation absorption at lower input irradiance and reverse saturation absorption at higher input irradiance and hence found to be a potential candidate for the third harmonic property based photonic devices.

Study of Third Order Optical Nonlinearity in Disperse Orange-25 Dye-doped Polymer Films using CW Laser

The organic materials with the ability of self-focussing/defocusing through their light intensity-dependent refractive index and phase shift properties are potential materials in alloptical photonic devices have become interesting topic of continuous research. Several organic materials including dye-doped polymer films are attracting many researchers due to their advantages in terms of enhanced efficiency, and acceptable mechanical properties to fabricate useful devices. In this paper, we have reported the nonlinear optical properties like nonlinear absorption and nonlinear refraction of an organic dye Disperse Orange-25 (DO-25) doped in Polymethyl methacrylate-methacrylic acid (PMMA-MA) polymer matrix using open aperture and closed aperture Z-scan experimental methods by means of low power continuous wave (CW) laser beam. The optical limiting properties of these films are also studied using Type 1 and Type 2 configurations at different input powers using continuous wave (CW) laser beams of 532 nm wavelength. The nonlinear refractive index n2, nonlinear absorption coefficient β, changes in refractive index with input intensity, and the magnitude of third-order optical nonlinearity of the dye-doped film are experimentally determined. The saturated output power for type 1 and type 2 optical limiting are determined. The input limiting threshold and saturated output power level for both type 1 and type 2 optical limiting configurations are recorded. DO-25 dye-doped in PMMA-MA polymer film has shown saturation absorption at lower input irradiance and reverse saturation absorption at higher input irradiance and hence found to be a potential candidate for the third harmonic property based photonic devices.

A Methodology for Implementation of High-Efficiency Broadband Power Amplifiers With Second-Harmonic Manipulation

This brief describes a methodology for designing broadband power amplifiers (PAs) based on the manipulation of second-harmonic impedance. The proposed approach starts from the inverse class-F (F−1) design specification and extends it to a family of specifications that allow achieving better than class-B performance in terms of output power and drain efficiency. It is shown that the achievable performance can be maintained over a wide frequency range reaching 57% of fractional bandwidth. As such, the proposed approach permits higher flexibility and offers relaxed matching constraints in implementing broadband high-efficiency PAs. For the experimental implementation, the proposed approach is adopted to implement a broadband PA using a 10-W gallium-nitride transistor. Peak drain efficiencies greater than 75% are measured over carrier frequencies between 500 and 900 MHz. The saturated output power levels, on the other hand, are higher than 10 W with a maximum of 13 W. Measured results are confirmed to be in good agreement with theory and simulations.

Silicon photonics WDM transmitter with single section semiconductor mode-locked laser

Abstract We demonstrate a wavelength domain-multiplexed (WDM) optical link relying on a single section semiconductor mode-locked laser (SS-MLL) with quantum dash (Q-Dash) gain material to generate 25 optical carriers spaced by 60.8 GHz, as well as silicon photonics (SiP) resonant ring modulators (RRMs) to modulate individual optical channels. The link requires optical reamplification provided by an erbium-doped fiber amplifier (EDFA) in the system experiments reported here. Open eye diagrams with signal quality factors (Q-factors) above 7 are measured with a commercial receiver (Rx). For higher compactness and cost effectiveness, reamplification of the modulated channels with a semiconductor optical amplifier (SOA) operated in the linear regime is highly desirable. System and device characterization indicate compatibility with the latter. While we expect channel counts to be primarily limited by the saturation output power level of the SOA, we estimate a single SOA to support more than eight channels. Prior to describing the system experiments, component design and detailed characterization results are reported including design and characterization of RRMs, ring-based resonant optical add-drop multiplexers (RR-OADMs) and thermal tuners, S-parameters resulting from the interoperation of RRMs and RR-OADMs, and characterization of Q-Dash SS-MLLs reamplified with a commercial SOA. Particular emphasis is placed on peaking effects in the transfer functions of RRMs and RR-OADMs resulting from transient effects in the optical domain, as well as on the characterization of SS-MLLs in regard to relative intensity noise (RIN), stability of the modes of operation, and excess noise after reamplification.

Concurrent Hex-Band GaN Power Amplifier for Wireless Communication Systems

In this letter, we propose a novel multi-section transmission line matching technique applied to the design of a concurrent hex-band HEMT GaN power amplifier (PA). The PA has been designed for a concurrent operation at 0.9, 1.8, 2.5, 3.5, 5.2, and 5.8 GHz. Experimental results have shown minimum and maximum saturated output power levels of 33 dBm and 36.7 dBm respectively over the different frequency bands, with the power added efficiency (PAE) ranging from a minimum of 20% to a maximum of 49%. A detailed comparison between simulation and experimental results data has also been reported.

A VSWR-protected silicon bipolar RF power amplifier with soft-slope power control

This paper presents the design and measured performance of a 1.8-GHz power amplifier featuring load mismatch protection and soft-slope power control. Load-mismatch-induced breakdown can be avoided by attenuating the RF power to the final stage during overvoltage conditions. This was accomplished by means of a feedback control system, which detects the peak voltage at the output collector node and clamps its value to a given threshold by varying the circuit gain. The issue of output power control has been addressed as well. To this end, a temperature-compensated bias network is proposed, which allows a moderate power control slope (dB/V) to be achieved by varying the circuit quiescent current according to an exponential law. The nonlinear power amplifier was fabricated using a low-cost silicon bipolar process with a 6.4-V breakdown voltage. It delivers a 33.5-dBm saturated output power with 46% maximum power-added efficiency and 36-dB gain at a nominal 3.5-V supply voltage. The device is able to tolerate a 10:1 load standing-wave ratio up to a 5.1-V supply voltage. Power control slope is lower than 80 dB/V between -15 dBm and the saturated output power level.

High saturation output power from a neodymium-doped fluoride fibre amplifier operating in the 1300 nm telecommunications window

Signal saturation characteristics of a Nd-doped single mode fluoride fibre amplifier for the 1300 nm telecommunications window have been investigated both experimentally and theoretically. Saturated output power levels in excess of +15 dBm for a launched pump power of 100 mW at 795 nm are reported.

Effects of semiconductor-optical-amplifier nonlinearity on the performance of high-speed intensity-modulation lightwave systems

It is shown that when the amplifier is driven near saturation, its inherent nonlinearity causes significant bit-pattern-dependent pulse distortion, particularly in the bit-rate range between about 2 and 32 GB/s. Without proper countermeasures, this distortion can degrade system performance appreciably due to two basic mechanisms. The first, which can result in a system power penalty of as much as 10 dB, occurs in a standard decision circuit that automatically sets the threshold voltage to the average signal level, rather than in the middle of the eye opening. The second mechanism, which occurs even with the threshold set properly, is due to the nonlinear enhancement of the simple linear intersymbol interference (ISI) within the receiver filter. For example, computations of system performance at 8 Gb/s using an RC filter that gives a quite acceptable 10% of eye closure under linear conditions show that when the amplifier is driven to its saturation output power level, this mechanism causes a system power penalty of about 1 dB, which increases to about 4.5 dB when the power is doubled. Interestingly, with the proper threshold setting, an ideal integrate-and-dump receiver, which introduces no ISI, is shown to suffer no power penalty due to amplifier nonlinearity.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Microwave properties and applications of negative conductance transferred electron devices

The transferred electron effect in epitaxial GaAs has been used to realize a semiconductor device which exhibits a stable negative conductance over a wide range of microwave frequencies and power levels. These devices have been used in conjunction with circulator coupled networks to design high-level wide-band transferred electron amplifiers which have a voltage gain bandwidth product in excess of 10 GHz for frequencies from 4.0 to about 16.0 GHz. Linear gains of 6-12 dB per stage and saturated output power levels in excess of ½ W have been realized. The physical and electrical properties of these devices are described with regard to the achievement of a stable negative conductance. The influence of several parameters (i.e., device temperature, bias voltage, circuit loading, etc.) is discussed with regard to device and circuit stability. Measurements of the terminal admittance of several typical devices as a function of the bias, input power, and frequency have been used to study their microwave properties. The large signal data are used to compute the relationship between the available device power and the magnitude of the negative conductance independent of the test circuit. This same measurement technique can provide a simulation of the performance of any nonlinear negative conductance, without the need for circuit design and load tuning. In addition, an analytical large signal model of the negative conductance has been used to predict the large signal performance of the active device (i.e., gain compression, conversion efficiency, etc.) in both oscillator and amplifier circuits.

A Eiiglh-Power Ferroelectric Limiter

A new type of solid state high-power limiter, which utilizes the large-signal nonlinear characteristics of ferroelectric materials, has been developed. Experimental 218 Mc units have handled peak input power levels in excess of 25 kw while yielding saturated output power levels of about 300 watts and a small-signal insertion loss of 0.5 db. The limiter consists of a symmetrical, loop-coupled, capacity-loaded, coaxial line cavity as shown in Fig. 1. A large portion of the capacity loading is provided by the ferroelectric pellet. Due to the large amount of capacitive loading yielded by the very high dielectric constant ferroelectric material, the cavity length is well under a quarter wavelength. An electric heater is located outside the cavity, but near the ferroelectric pellet, in order to bring the pellet temperature within a few degrees of its Curie temperature. Figure 1 also contains an expanded drawing of the region near the ferroelectric peIlet. The power handling capability, saturated power output level, and small-signal insertion loss are determined by the radius (r/sub f/) and height (d/sub f/) of the ferroelectric pellet. High-voltage breakdown in this region is retarded by coating the lateral surfaces of the ferroelectric pellet and its supporting brass posts with corona dope. The entire assembly is also filled with sulfur hexafluoride gas (SF/sub 6/) as a further precaution against high-voltage breakdown.