| Along with the development of optical transport network and optical access network, the the requirement of the devices quality increases and continues to expand to the areas of switching, wireless communication, optical interconnection and sensors, the research of the optical devices play an important role to influence and work as a driving force to promote the development of the whole optical communication network. Among all the optical devices, the amplifier and optical source gain a lot of interests. The optical parametric amplifier (OPA) can realize low noise amplification and full coverage of communication band, so it is considered as a potential device for amplification and signal processing in next generation optical network. Radio on fiber (ROF) technology can combine the merits of optical and wireless communication network and realize the wideband wireless access. It is a promising technology in access network. This article is mainly focused on silicon-based OPA and the optical source for ROF system.The main research work of this dissertation are classified as two aspects and listed as below:I Silicon-based OPA technologiesBased on the quantum theory of optical transmission, on one hand, net gain, noise figure and phase regeneration of phase-sensitive optical parametric amplifier (PS-OPA) have been studied. On the other hand, the phase-insensitive optical parametric amplifier (PI-OPA) in silicon microring resonator has been investigated, several loss mechanisms involved and coupling coefficient have been discussed and optimized. The work mainly includes the following parts:(1)Based on the classical quantum theory, by calculating photon-number expectation and variance, the function of NF has been deduced and analyzed under the assumption of large photon number. The results show that the NF of phase insensitive (PI) OPA is 3dB, NF of the phase sensitive (PS) OPA is OdB. The reason of low noise for PS OPA is discovered and explained in detail.(2) The net gain and NF of symmetric-pump (SP) PS-OPA have been analyzed in theory. Influence of inherent nonlinear effects in silicon like two photon absorption (TPA) and free carrier absorption (FCA) are discussed. In addition, the phase regeneration performance of SP-PS-OPA has been analyzed and optimized by choosing suitale dispersion, free carrier lifetime and input phase.(3)The net gain and noise of non-degenerate PS-OPA have been analyzed in detail. The results showed that the input relative phase plays an important role in silicon non-degenerate PS-OPA. The net gain, NF and output phase changed periodically along with the input phase. In silicon-based PS-OPA, while nonlinear phase noise (PN) can be declined directly, linear phase fluctuation can also be depressed. Assuming the linear phase fluctuation of input signal is 0.05?the fluctuation of output phase can be decreased to below the half of input fluctuation. For net gain and low noise, free carrier lifetime should be kept below 400ps.(4) OPA in a silicon-based microring resonator is proposed and modeled. Net gain can be achieved by properly adjusting pulse width, repetition rate of the pump and free carrier lifetime of material to reduce the nonlinear losses caused by TPA and FCA. For high steady net OPA in MRs, the carrier lifetimes should be kept below 100ps and coupling coefficient?should be keep in the suitable range from 0.25 to 0.5. Furthermore, the MR with high enhancement factor can reduce the pump power and waveguide length. These capabilities enable the integration of OPA. These results make some useful suggestions to the practical use of integration OPA. ?The source for ROF system(1)A millimeter-wave (mm-wave) multi-channel source generating method for wavelength division multiplexed (WDM) radio-on-fiber (ROF) systems is proposed and demonstrated experimentally. In this scheme, a femto-second semiconductor mode-locked laser is used as the source, two 5-m-long photonic crystal fibers (PCFs) with opposite dispersion are used to generate supercontinuum, then a sampled fiber Bragg grating (SFBG) is used to slice the generated supercontinuum. Based the supercontinuum with flatness of±0.15dBm, more than 10 channels millimeter-wave optical carriers have been generated with±0.3dBm Peak fluctuation for WDM-ROF system. These ten-channel carriers have some characteristics like small gain fluctuation, large modulation depth and narrow width, and so on. Besides, the whole system can be easily integrated due to simple structure and small insertion loss.(2)The optical carrier suppression (OCS) mm-wave generation based on saturated OPA effect in the high nonlinear fiber has been proposed and simulated. This proposed scheme can enhance the sensitivity of receiver and decline the penalty after long-haul transmission. Meanwhile, it can also simplify the system and reduce the cost of ROF system by avoiding the use of high rate external modulator, high-frequency RF sources and narrow-band filters. |
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