Sökning: "Phase locking"
Visar resultat 1 - 5 av 35 avhandlingar innehållade orden Phase locking.
1. Optical Transmission Systems Based on Phase-Sensitive Amplifiers
Sammanfattning : The capacity and reach of today's long-haul fiber optical communication systems is limited by amplifier noise and fiber nonlinearities. Conventional, phase-insensitiveamplifiers (PIAs), have a quantum limited noise figure (NF) of 3 dB at high gain, meaning that with a shot-noise limited input signal the signal-to-noise ratio (SNR)is degraded by at least 3 dB. LÄS MER
2. Phase Sensitive Amplifiers for Free-Space Optical Communications
Sammanfattning : The demand for high data rate free-space communications is increasing due to the planned future space exploration missions. In the next few years there is a need to increase the speed by 100 times according to NASA, and this necessitates that transmission systems operate at higher carrier frequencies. LÄS MER
3. Low noise frequency combs and injection locking for broadly tunable laser sources and tomography
Sammanfattning : Lasers have revolutionized the world of physics by providing a highly coherent source of photons which may be used for a large variety of purposes. Here, we study the noise properties of frequency combs - a special class of frequency stabilized and mutually coherent multi-mode lasers, as well as the optical injection locking of comb tones as a means for low noise amplification and tone selection. LÄS MER
4. Towards Practical Implementation of Phase-Sensitive Amplifier Based Transmission Systems
Sammanfattning : All commercially available optical amplifiers are so-called phase-insensitive amplifiers (PIAs) which degrade the signal-to-noise ratio (SNR) through the amplification process. This kind of amplifier has a quantum limited noise figure (NF) of 3 dB. LÄS MER
5. Design and characterisation of terahertz Schottky diode harmonic mixers
Sammanfattning : Efficient, compact, and reliable terahertz frequency converters preferably operating at ambient temperature are crucial for stabilising far-infrared optical sources. This thesis focuses on the design and characterisation of terahertz Schottky diode harmonic mixers for frequency stabilisation of quantum-cascade lasers. LÄS MER