Power self-regulation in double-pass high-gain laser amplifiers

Abstract

Gain saturation and high-power pulsed operation of GaSb-based tapered diode lasers with separately contacted ridge and tapered section Double-pass laser amplifiers can provide automatic passive regulation of the power in an optical signal. This regulation can significantly reduce the amplitude noise on a laser beam that is intended as a continuous wave light source. Analytic expressions are derived to describe the optical-noise-reduction region of double-pass amplifier operation and the dependence of the self-regulation properties on gain, saturation, and mirror reflectivity.

Efficient modulation cancellation usingreflective SOAs

“…Because of the strong gain saturation, the RSOA experiences a large gain reduction by 28 dB at an input power of about 0 dBm. Further increases in input power results in such a large gain saturation that the output power decreases with increasing input power, this is consistent with the results in [7,10]. To illustrate this point further, the steady-state, spatially resolved counter-propagating waves and carrier densities are plotted in Fig.…”

“…We highlight regimes of operation where the modulation component of the output signal is (a) moderately squeezed (b) exactly cancelled (c) inverted. The inverted regime occurs when the output power decreases with increasing input power [7] and is termed here as signal self-inversion because the strong self-gain saturation causes the residual modulation on the outgoing wave to be an inverted copy of the incoming modulation. As a consequence of this signal self-inversion effect, there exists an optimal input optical power to achieve modulation cancellation in RSOAs.…”

“…As a consequence, the forward and backward traveling waves compete for gain from the same source of carriers, and due to this feedback process the gain saturates more strongly. An approximate analytic approach to calculate the static gain saturation of generalized reflective amplifiers was presented in [7]. For low values of reflectivity, < 50%, there exists a local maximum in the output power with respect to the input power.…”

Extended-reach PON employing 10Gb/s integrated reflective EAM-SOA

“…The device is in gain saturation for all input powers analysed and the output power is clamped at 0dBm for input powers higher than −10dBm. This characteristic behaviour results from the relatively high loss between the SOA and the high reflectivity rear facet, which is induced by the EAM and EAM-SOA interface [7]. Fig.…”

Improved reduced models for single-pass and reflective semiconductor optical amplifiers

“…In general, the output power characteristics of reflective amplifiers differ from single pass amplifiers in that a maximum output power is reached at a certain input power [11], and this was shown experimentally and numerically for RSOAs [10], [12]. Simplified travelling wave models for RSOAs have appeared [3], [4], with the model in [3] introducing a lumped RSOA model that shows nice agreement with the full travelling wave model in [4].…”