Gain-clamped fiber amplifier with a loop mirror configuration

A new configuration of a gain-clamped fiber amplifier is proposed and demonstrated. A laser cavity was formed by a fiber grating and a loop-mirror containing an erbium-doped fiber amplifier in its loop. Owing to the loop-mirror property, the signal light does not enter the laser cavity, and the signal light around the oscillation wavelength can be amplified in the same way as signals far from the oscillation wavelength. Our configuration also has an advantage that only the signal light appears at the output port     

All-optical high speed demultiplexing with a semiconductor laser amplifier in a loop mirror configuration

A novel, purely optical technique for demultiplexing high speed time-division multiplexed data is demonstrated. The technique uses the SLALOM (semiconductor laser amplifier in a loop mirror) The data rate is not limited by the gain recovery time of the semiconductor laser amplifier. The same technique can also be used for multiplexing.<>     

SLALOM: semiconductor laser amplifier in a loop mirror

The processing of optical signals in the optical domain is an important issue resulting from the desire to take advantage of the full bandwidth of the optical fiber. In this paper, we present detailed investigations on a device, which utilizes a semiconductor laser amplifier in a loop mirror configuration (SLALOM). Different modes of operation are reported like nonlinear single pulse switching and two-pulse switching at different operation speeds (1-100 Gb/s). Furthermore, a number of applications of the SLALOM in photonic systems, like pulse shaping, decoding, retiming and time-division demultiplexing, are presented. In addition, the SLALOM can be used for an estimate of the linewidth enhancement factor α and the carrier lifetime τ _e in an SLA     

Optical loop mirror with semiconductor laser amplifier

A nonlinear optical loop mirror is reported, employing a semiconductor laser amplifier (SLA). The input-output characteristic is distinctly nonlinear, and when operating as an optical correlator, an extinction ratio of 13 dB was achieved.<>     

Multiwavelength all-optical TDM switching using a semiconductoroptical amplifier in a loop mirror

We report simultaneous all-optical switching of multiple wavelengths using an optical loop mirror with an asymmetrically placed semiconductor optical amplifier. Switching is shown for 14-wavelength channels (across 14-nm bandwidth) with switching contrast of 10-23 dB     

基于级联光纤环形镜的增益平坦掺铒光纤放大器

基于光纤环形镜的滤波原理,提出利用级联结构光纤环形镜(FLM)实现掺铒光纤放大器(EDFA)增益平坦滤波的方案,并进行了相关实验研究.实验结果显示,使用级联FLM取得了明显的增益平坦效果,其1535-1557nm波长范围内的增益不平坦度由±5dB减小到±1dB.     

All-optical loop mirror switch employing an asymmetric amplifier/attenuator combination

For the first time a report is made on a loop mirror switch containing the nonreciprocal combination of a semiconductor laser amplifier and an optical attenuator. Self-routing of optical pulses has been demonstrated on 10 ns pulses with powers of <250 mu W, within a 17 m loop. The model predicts the form of the switching.<>     

Gain flattening of an erbium-doped fiber amplifier using ahigh-birefringence fiber loop mirror

We propose a flexible method for flattening the gain profile of an erbium-doped fiber amplifier (EDFA). The method is based on a high-birefringence fiber loop mirror (HiBi-FLM), which contains a number of high-birefringence fiber sections and polarization controllers. We show that, by setting the polarization controllers properly, the reflection spectrum of the loop mirror can be adjusted to compensate for the variations in the gain profile of the EDFA. The method is demonstrated experimentally by using a single-section HiBi-FLM and a two-section HiBi-FLM, respectively, With a two-section HiBi-FLM, we are able to flatten the gain profile of an EDFA to within ±0.9 dB over a bandwidth of 33 nm at the center wavelength of 1543 nm, under different operating conditions of the EDFA     

Regenerative 20 Gbit/s wavelength conversion and demultiplexingusing a semiconductor laser amplifier nonlinear loop mirror

A nonlinear loop mirror containing a semiconductor laser amplifier is used to perform all-optical wavelength conversion and demultiplexing at 20 Gbit/s. This technique has a low polarisation sensitivity and offers a regenerative function where jitter in the received data is considerably reduced     

Four-frequency parametric amplifier

In this letter, relationships between gain, bandwidth and network parameters are derived for the four-frequency parametric amplifier. The method utilised here is similar to the technique employed by Matthaei in the analysis of the threefrequency parametric amplifier and upconvertors.     

Hybrid parametric amplifier

The letter proposes a hybrid parametric amplifier in which the signal circuit is a travelling-wave structure and the idling circuit is resonant. A simple expression for the available gain per section is calculated together with typical circuit values.     

Surface-acoustic-wave parametric amplifier

Parametric amplification and oscillation of surface acoustic waves has been observed on lithium niobate by varying the stiffness of the surface within a resonator cavity.     

Adaptive-optics compensation in a Raman amplifier configuration

An experimental study of real-time adaptive compensation through a high-gain Raman amplifier is discussed. Atmospheric turbulence was simulated by selectively aberrated quartz plates designed to produce a turbulence-like phasefront distortion on a transmitted beacon. A 69-channel wavefront sensor measured the beacon's phasefront and commanded a deformable mirror to impose the conjugate phasefront on the Stokes seed to a high-gain, large-Fresnel-number Raman amplifier. After amplification, the output Stokes beam was made to retrace the path of the beacon back through the simulated turbulence. Measurements of the Stokes beam quality indicate a dramatic improvement to near-diffraction-limited performance. The experimental results are in good agreement with theory     

Pulse saturation in a traveling wave parametric amplifier

The pulse saturation on a nondispersive traveling wave parametric amplifier is solved in the slowly varying approximation with space and time by reducing the dynamic equations to a degenerate form-of the sine-Gordon equation. If the group velocity of the signal wave differs from that of the pump and idler waves, the signal wave obeys the sine-Gordon equation.     

Optimal loop length of a nonlinear optical loop mirror in switchingsolitons

The optimal loop length of a nonlinear optical loop mirror (NOLM) for switching solitons was investigated numerically for the case where the wavelengths of the control pulse and signal soliton straddle the dispersion zero. In our analysis, the Raman effect is also included because the wavelength difference between the control and signal pulses is within the Raman gainband. It was found that the control pulse not only imposes phase shift on the copropagating signal, but also transfers part of its energy to the signal. Furthermore, the broadening of the control pulse due to the combined effect of self-phase modulation and group velocity dispersion increases the switching power of the control pulse significantly. The broadening of the control pulse also introduces more uniform phase shift to the signal, thus resulting in a higher switching efficiency. Finally, our results show that the pulse distortion is minimal if a loop length equivalent to one soliton period is employed     

CMOS parametric current amplifier

The current amplifier presented is based on a gate-bulk-source translinear loop of MOSTs biased in weak inversion. Large gain factors are achieved with the consumption of only a small area. Gain is controlled by a ratio of bias currents     

Possible Gunn-effect parametric amplifier

It is proposed that the moving domain in a Gunn-effect sample can be regarded as a pumped capacitor and that this can be used to form a single d.c.-pumped parametric amplifier. The idling current can be supported in the resonance provided by the encapsulation. The figure of merit is calculated.     

The variable-capacitance parametric amplifier

The physical principles involved in the operation of the major types of variable-capacitance parametric amplifiers are reviewed and a qualitative explanation is given of the variable-capacitance effect in semiconductor diodes. The utilization of these principles and also of these diodes in a number of experimental, low-noise amplifiers is described. A comparison is given of the best noise performance obtained to date with experimental vacuum-tube amplifiers with that of parametric amplifiers. This paper is directed primarily at nonspecialists who wish to acquire some familiarity with a new and fast-moving field.     

Self-pumped Gunn-effect parametric amplifier

The letter reports the operation of a degenerate parametric amplifier which utilises the self-pumping action of the oscillating domain capacitance in the Gunn effect. Gains greater than 20dB at 5.98GHz have been obtained with the Gunn sample oscillating at 11.96GHz. Amplification is also reported in the normal negative-resistance mode, and an experiment is described which is designed to distinguish between the two modes of amplification.