PAM-XIAMEN can offer epitaxy wafer of silicon for manufacturing integrated optical waveguide devices. The silicon epi wafer we offer is grown core layer of Si and lower cladding layer of SiO2 on Si substrate and the waveguide structure is ridged. Due to the large refractive index difference between Si and SiO2 materials, this structure can confine light to transmit in the top-layer silicon structure, and easily obtain small-sized and compact optical waveguide devices. More parameters of the silicon epi wafer, please view the table as follows:
1. Specification of Si Epitaxy Wafer for Integrated Waveguide Optics
The silicon wafer epitaxy below is suitable for fabricating devices of integrated waveguide optics of telecommunication wavelength range.
|Wafer Material||monocrystalline silicon|
|Layer Material||Silicon Oxide|
|Layer Material||monocrystalline silicon|
|Conductivity Type||p/B or self-conductance without doping|
|Crystal Orientation||(1-0-0) ±0.5°|
|Surface Contamination (number of particles)||no more than 50 particles of 0.3|
2. Why Choose Silicon as Optical Waveguide Material?
The reasons for choosing silicon material for making optical waveguide mainly are:
1) The absorption coefficient curve of silicon is shown in the figure 1. It can be seen that the absorption coefficient of silicon materials at wavelengths above 1300 nm is relatively small (<1e-5 /cm), so the light transmits in it, and the intrinsic loss is very small.
Fig.1 Absorption Coefficient of Silicon
2) The refractive index of silicon is 3.48, and the refractive index of silicon dioxide is 1.44, and the refractive index contrast of the two reaches 0.41 (index contrast = (n1^2-n2^2)/2n1^2). Therefore, light can be better bound in the silicon waveguide. The size of the waveguide is smaller, more optical devices can be included in an optical chip with the same area, and the chip integration degree is higher. The figure 2 is a comparison of common optical waveguides of different materials. It can be seen that waveguides based on silicon epitaxy wafer have the highest device integration.
Fig.2 Comparison of Optical Waveguides with Different Materials
3) The processing of the silicon epitaxial film wafer is relatively simple, whether it is the etching, epitaxy process, or doping of the waveguide. The fabrication process of the silicon waveguide is compatible with the CMOS process, which is conducive to mass production.
3. What Is Optical Waveguide?
An optical waveguide is a medium device that guides light waves to propagate in it, also known as a medium optical waveguide. There are two types of optical waveguides: one is integrated optical waveguides, including planar (thin film) dielectric optical waveguides and strip-shaped dielectric optical waveguides, which are usually part of optoelectronic integrated devices (or systems); the other type is a cylindrical optical waveguide, commonly referred to as an optical fiber.
Therein, the planar dielectric optical waveguide is the simplest optical waveguide. It uses silicon (or gallium arsenide, or glass) with a refractive index of n2 as a substrate, and uses a microelectronic process to coat it with a dielectric film with a refractive index of n1, plus a cladding layer with a refractive index of n3. Usually take n1>n2>n3 to confine the light wave to propagate in the dielectric film. The strip-shaped dielectric optical waveguide is to generate a strip with a refractive index of n1 in a matrix with a refractive index of n2, taking n1>n2, so as to confine the light wave to propagate in the strip. Such optical waveguides are often used as optical splitters, couplers, switches and other functional devices.