High-gain Semiconductor Optical Amplifier Research Articles

Advantageous Effects of Gain Saturation in Semiconductor Optical Amplifier-Based Integrated Reflective Modulators

Reflective modulators based on an electro-absorption modulator (EAM) and semiconductor optical amplifier (SOA) combination are attractive devices for applications in carrier distributed optical access networks due to the gain, provided by the SOA, and the high speed and low chirp modulation of the EAM. Monolithically integrated reflective EAM-SOAs (R-EAM-SOAs) have demonstrated unexpected and unintuitive behavior, which is related to the gain saturation properties of the SOA section and also to the internal loss present after the SOA section. Results from a simple analytical model and from an accurate numerical model show that a high value of internal loss and a high gain SOA allow utilization of these devices in a region where the output power is clamped around a maximum value for input carrier powers compatible with carrier distributed optical access networks. In this region of operation the R-EAM-SOA also exhibits low patterning distortion, despite being in a saturated regime, and noise reduction on the input carrier due to the noise squeezing in the SOA section. In this paper, we demonstrate that these three effects, which are highly desirable in carrier distributed optical access networks, can be readily achieved via a co-optimization of the SOA section parameters and the internal loss values in integrated R-EAM-SOAs.

Demonstration of high saturation power∕high gain SOAs using quantum well intermixing based integration platform

The performance of semiconductor optical amplifiers (SOAs) employing regions of high and low optical confinement designed for high saturation power and high gain using a novel quantum well intermixing and MOCVD regrowth fabrication scheme is reported. The scheme enables the monolithic integration of high performance SOAs with high gain laser diodes, high efficiency electroabsorption modulators, and high saturation power photodiodes. The SOAs presented exhibit saturation powers in the 19 to 20 dBm range with nearly 15 dB of gain.

High-gain array of semiconductor optical amplifier integrated with bent spot-size converter (BEND SS-SOA)

We propose a high-gain semiconductor optical amplifier with an integrated bent spot-size converter (BEND SS-SOA). A straight active waveguide enables us to use a pn-buried heterostructure (pn-BH) with a high current-blocking effect and uniform characteristics. We can optimize a bent spot-size converter waveguide to provide low optical feedback from the facets and high-coupling efficiency to a flat-end optical fiber with low radiation loss due to the bend. The devices we fabricated achieve a high fiber-to-fiber gain of 18 dB with a coupling efficiency of -3.5 dB, and we have demonstrated a four-channel array with uniform characteristics.