Silicon Photonics Lead The Trend Of 100G Network


FiberStore news, when assembled eliminated pure handmade reliable optical components containing hundreds of optics, steering the occasion of silicon photonics technology, the industry will enter a new better world. On the other hand, switching network upgrade from 10G to 100G, even when eventually reach 1TB, will also face tough challenges from silicon photonics technology. Some optical function is easy to realize by silicon, but some are not. In fact, the entire optical engine must be integrated in silicon platform.

Optical engine can handle multiple high-speed electrical channels, converts it to optical signal, then together the information on these channels, through an fiber optic to transmit the information to any location ─ ─ distance from near to the next frame or as far as across the entire data center from the other end. At the receiving end, optical engine will flow received light streams separate into different channels, and then converted back to radio channel. In the data center, optical engine used for connecting the cluster switches and routers, which is a low power consumption, smallest pluggable transceiver technology; optical engine is also used in active optical cable to connect to the server and switch. In addition, the optical engine soon will also be embedded into the splint (mid-board) in order to reduce the consumption of board to board application and increase the density.

However, integrating optical functions on CMOS platform will encounter many challenges, which is original used to realize electric function design. Take a look at each key photoelectric function and the challenges of its fully integration in a CMOS platform.


Laser provides fiber optic light source for the optical engine, but to some data centers, using laser is too expensive. Kotura has developed chip function by using low-cost low-speed laser. Laser is a type of optical component which has not achieved single-chip integration, but the latest development of laser and array of flip chip bonding technology, have made it into a large number of low-cost manufacturing process. Chip functions removed the lens, isolator and beam collimator needed by traditional laser subassembly. The design of Kotura laser removed the expensive sealed package. In the automated assembly platform, just a few seconds for the array laser entire fabric and welded to silicon photonic chip, but also overcome the difficult problem of low-cost light source integrated in the chip.

The real value of fiber optic network is the ability to combine multiple wavelengths of light into one entity channel. To the 100G interconnection,the use of this called wavelength division multiplexing (WDM) parallelism, put the light combination of four wavelengths in a fiber. Of course, the four parallel fiber channel can work, but this increases the cost of network, but also a waste of bandwidth of fiber optic. WDM makes the use of same data center architecture to expend become possible, in order to support more channels in the future.

Because WDM requires both specific wavelength and multiplex wavelength laser, and therefore using silicon photonics to achieve is not easy. Nevertheless, the industry still don’t want to use the expensive specific wavelength laser, which is commonly used in telecommunications network. A better solution is to use a universal laser, through integration of optical switch reflector in the silicon chip changes universal laser into specific wavelength laser. By changing the position of the reflector, Kotura will make each gain chip becoming a unique specific wavelength laser.

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