Investigation Of Metal-Caldding Optical Waveguide With Submillimeter Scale And Its Application

Recently, the study of optic-electronic devices based on optical waveguide has become a study focus. At first, we present a new kind of optical waveguide, named double metal-cladding optical waveguide (MCOW), developing from common dielectric plane waveguide. The structure of this optical waveguide is composed of guiding layer and two metal films, which are used as cladding layer. The upper metal film is also used as coupling layer. A so called free space coupling technique is developed, called as free space coupling. We demonstrate theoretically and experimentally that the ultra-high order modes in MCOW with sub-millimeter scale are polarization independent, sensitive to the refractive index and thickness of the guiding layer and the incident wavelength and it has the characteristic of high dispersion. These characteristics are very useful in the research of optic-electronic devices.Since 1980s, people have paid more and more attention to the smart sensors based on the technique of surface plasma resonance, optical waveguide and optical fiber. The same characteristic of this kind of sensors is that the samples to be measured are both deposited in an evanescent field. So these sensors are called evanescent field sensors. Because of the rapid attenuation property of the evanescent field, these sensors'sensitivity is limited to less than 1.According to the characteristic that the ultra-high order modes are sensitive to the parameters of the waveguide, a new oscillating wave sensor based on the metal-cladding optical waveguide with sub-millimeter is proposed. The sensor contains the sample in the core region which supports the oscillating field. Owing to the strong concentration of the electromagnetic field in the sensing medium and the high sensitivity of the ultrahigh-order modes, the proposed sensor exhibits several orders of magnitude of enhancement of the evanescent field sensors.As the technique of chirped pulse amplification (CPA) develops, the fs and 100TW optical pulses are available in the laboratory. The CPA technique is to let the optical pulses pass through a pair of anti-parallel gratings. And the positive contribution of the group-velocity dispersion can make the pulses have a time delay. So the pair of anti-parallel gratings is called a pulse stretcher. Then the pulses is amplified in the optical amplifier. The last step is to compress the pulses by using a parallel gratings which have the negative contribution of the group-velocity dispersion. It's a very important part of a good pulse stretcher in the CPA technique. Although the pair of anti-parallel gratings can stretch the optical pulses, it's difficult to operate.In this paper, we propose a novel pulse stretcher based on the metal-cladding optical waveguide with sub-millimeter. By using the free-space technique, ultrahigh-order modes are excited in the optical waveguide. Because of the ultrahigh-order modes'characteristic of high group velocity dispersion, 1 ps pulses can be stretched to as high as 1000 times when they propagate in the waveguide for 1.26 mm.