Optical Directional Coupler

Currently, optical fiber communications using the most integrated optical devices are mainly: the optical coupler (Coupler to Splitter), optical modulators, optical switches, tunable optical filter (OTF), and so on.

 Optocoupler

    Optocoupler is functional devices, optical signal splitter / combiner is generally on the same wavelength of the optical power splitter combiners. Coupler for optical fiber communication is divided into: the fiber fused taper coupler, the coupler of the MEMS device type (MEMS) and integrated optical waveguide coupler. Here are the integrated optical waveguide coupler.

    Integrated optical waveguide couplers using planar optical waveguide technology can be made ??into a different structure and function of its main processes: deposition, photolithography, diffusion. The most simple is the basic structure of the (1 × 2) Y-branch coupler.

 The optical switch using electro-optic effect of the waveguide material of the waveguide refractive index modulation to achieve the purpose of the switch by changing the optical path. Typical materials suitable for making optical switch for optical fiber communication systems Si, GaAs, InP.
 Optical switch can be divided into three categories: directional coupler type, the interference type, Y-branch type.

 Directional coupler type optical switch rely on one pair of very close to the strip waveguide and a surface electrode located in the strip waveguide. Injection current to change the refractive index of the waveguide arm, resulting in the energy coupling between two adjacent waveguides to achieve the switching of the transmission channel. The coupling length and the spacing between adjacent waveguides determines the ratio of the energy coupling between the waveguide.

 In a variety of integrated optical devices for optical fiber communication devices have made ??great strides, and has a certain scale. However, the development of optical fiber communication calls for a more comprehensive indicator of more advanced integrated optical devices. Common development at this stage fiber optics and integrated optics, complement each other; discrete devices and integrated optical devices will coexist for a long time, but the trend is integrated.

    Now, the integrated optical device is still in the early stages of research and development stage, the integrated scale, the performance of the device, the size of the market is far and microelectronic devices compared. But as a key component of optical network in the 21st century, the integrated optical device will certainly occupy a very important position.