Basic Study On Er～(3+)-Yb～(3+) Co-doped Polymeric Optical Waveguide Amplifiers

With the rapid development of optical communication technology and integrated optoelectronics, the research of optical waveguide amplifiers used in optical communications have drawn more and more attentions for it's high gain, small volume, compact structure, convenient integration and low loss. Erbium doped optical waveguide amplifier (EDWA) is another new kind of optical amplifier followed the Semiconductor optical amplifier (SOA) and Erbium doped fiber amplifier (EDFA). These years research about EDWA is becoming a hotspot in the region of optical fiber communication and photoelectronics. At the same time, in the circuit of optical communication consisted of separate components and in the planar light-wave circuits (PLC), all kinds of optical components have losses. It urgently needs a new kind of amplifier which is in low price and can be integrated easily. EDWA is an optimized selection for an appropriate gain. Among all the materials which are used in the integrated optics, polymer material compared with the traditional inorganic materials has some merits like high rare-earth ions doped concentration, easy control of the refractive index, relatively high electric-optic coupling coefficient, relatively low dielectric constant, short response time, low thermal losses, small birefringence, easy fabrication, cost-effectiveness and so on. For these reasons enumerated above, the research into polymeric optical waveguide amplifier is becoming a increasing focus.Erbium-Ytterbium co-doped polymeric optical waveguide amplifier is prepared by doping Er3+ and Yb3+ ions into polymeric material and making use of reactive ion etching technology (RIE) with photoresist and aluminum film as mask above the polymer material based on silicon substrate. Then a pump power in 980nm region will be added to realize amplifying the optical signal in 1550nm region. In this thesis we study the Erbium-Ytterbium co-doped polymeric optical waveguide amplifier. The main content is listed as follows:1. Firstly we summarized the main technology in the research aboutEDWA and reviewed the developing process and achievement in recent years about fiber optical communication and EDWA. Also, we talked about the characteristic and foreground of EDWA and pointed out the importance of making scientific researches on Polymer EDWA.2. According to the basic theories of designing a rectangular optical waveguide, we obtained the relationship of the core thickness changed with the effective refractive index through calculating. The graph showed that the thickness range to keep a single-mode transmission is 2.4μm~4.6μm. We analyzed the theory of optical waveguide amplifier by analyzing the energy level structure of Er3+ and explained the theory how the optical waveguide amplifier amplifies the optical signal. Then we introduced the gain coefficient of medium and the condition to realize optical amplifier, the factor influence on the gain and the improvement of optical gain using Erbium-Ytterbium co-doped technology.3. We introduced and characterized the polymeric material which was used to prepare the waveguide. We analyzed the surface of the polymer with the Atomic Force Microscope (AFM), and used ellipsometry to measure the film-formed characteristic and refractive index of the material. We obtained the relationship between the refractive index and the content of bis-phenol-A epoxy, as well as the relationship between the thickness and the spin rate. It showed that the polymer we used is suitable to make the waveguide. Also we obtained the PL spectrum of the Erbium-Ytterbium co-doped polymer in the 1550nm region with the self-regulating device. The PL spectrum has a wide Full Width at Half Maximum (FWHM) of 80nm. It showed that this material can be used to prepare amplifier that amplifies the signal in the 1550nm region in optical communication, and will has a good advantage in bandwidth. Then we designed two different processes of preparing waveguide and introduced the main technics like vaporizing aluminium film, photolithography and reactive ion etching (RIE). At last we observed the waveguide prepared follow the two processes with microscope and Scanning Electron Microscope (SEM), and obtained the preconcerted result.4. We tested the property of waveguide amplifier in the way of coupling the fiber to the waveguide directly. We introduced the theory about how the fiber couple with the waveguide and analyzed some coupling loss in this process. Then we designed and constructed a system which used to test the output signal and the gain of waveguide amplifier. With this system, we tested the output light spot, spontaneous radiation spectrum, and optical gain and obtained the follow result: the wavelength at spontaneous radiation spectrum's peak value would move when pump power is changing; photoluminescence power became larger while the pump power was increasing; a 1.4dB gain can be obtained as pump power was added. All the above showed us that our polymer material is suitable to prepare the waveguide amplifier.