High-gain low-noise mid-infrared quantum cascade optical preamplifier for receiver

Wireless Myths, Realities, and Futures: From 3G/4G to Optical and Quantum Wireless

“…The development of powerful coherent detection schemes is a potential candidate in the longer term; after all, coherent systems are finding favor in high data-rate optical fiber systems, where sophisticated, but increased complexity modulation schemes can be used to increase the achievable spectral efficiency. Param-etric amplification 13 has also been investigated [106], as well as optical amplification using fiber [107] and semiconductor [108] amplifiers have been conceived. Both of these require Bcollecting[ the free-space radiation into a waveguide, albeit the loss in achieving this may be almost as high as the gain of the amplifier.…”

Master-oscillator power-amplifier quantum cascade laser array

“…3 shows the lateral far-field intensity distribution for three representative devices as measured by a Mercury Cadmium Telluride detector at a distance of 9 cm from the output facet. Nine devices (2,3,4,5,7,10,11,13,15) show pure TM 00 operation with full width at halfmaximum (FWHM) angles between 5:6 and 7 (represented by the red curve in Fig. 3).…”

“…An increase of the volume of the gain medium by increasing the laser ridge width above a certain value results in higher-order lateral modes which compromise beam quality. The integration of a quantum cascade optical amplifier 10 with a DFB QCL has demonstrated the possibility to combine the excellent beam quality of a DFB QCL with high power amplification in a monolithically integrated device. 11 The monolithically integrated masteroscillator power-amplifier (MOPA) configuration had been applied to diode lasers 12,13 for considerable time until its realization based on a QCL.…”