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
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.

Depth Analysis of Fiber Optic Testers (Part 2)

Another two fiber optic testers are optical power meter and optical light source.

Optical Power Meter

Optical power meters are used to measure the absolute optical power or the relative length of optical fiber optical power loss. Measuring optical power is the most basic in the fiber-optic system. Very much like the electronics multimeter, in optical fiber measurement Optical Power Meter is a heavy-duty commonly used table, and it is suggested that each of the fiber optic technicians should staff one. Through the measurement of the absolute power of the transmitting end optical network, a power meter can be able to evaluate the performance of the light end equipment. With an optical power meter and stabilized optical light source used in combination, it is possible to measure the connection loss, test continuity and help evaluate the transmission quality of fiber link.

For any manufacturing of optical fiber transmission system, installation, operation and maintenance, optical power measurement is essential. In the field of optical fiber, if there are no optical power meters, any engineering, laboratory, manufacturing floor or telephone maintenance facilities are unable to work. For example, Optical Power Meter can be used for measuring the output power of the laser light source and the LED light source; used to confirm the estimate of the loss of the optical fiber link; most important of which is that it is a test optical components (fiber, connectors, connecting sub, attenuator key performance indicators, etc.) instrument.
Specific applications for users to select the appropriate optical power meter, should pay attention to the following points:
1). Select the optimal probe type and interface type.
2). The evaluation calibration accuracy and manufacturing calibration procedures, and the required range of optical fiber and connector match.
3). Determine if the model is consistent with the measurement range and display resolution.
4). With the direct dB insertion loss measurement function.

Optical Light Source

Optical light source are used transmitting the light with known power and wavelength to optical system. As mentioned, a stabilized light source together with an optical power meter, can measure the optical loss of the optical fiber system. In off-the-shelf optical fiber system, usually the transmitting end of the system machine plays a role as a stable light source. If the end of the machine does not work or does not end machine, you need to separate stable light source. The stability of the wavelength of the light source should be as consistent as possible with the wavelength of the system end machine. After installation of the system, often need to measure the end-to-end loss, in order to determine whether the connection loss to meet the design requirements, such as: measuring connectors, splices point loss, and optical fiber body loss.

Optical light source transmit the light wtih known power and wavelength to enter the optical system in the process of measuring loss. Optical power meter which is used calibrating a specific wavelength light source, will receive light from the optical fiber network and convert it into electrical signals. To ensure the accuracy of loss measurement, the transmission equipment taht used in the fiber optic light source simulation should have these features.
1). The same wavelength, and uses the same type of light (LED, laser).
2). During the measurement, ensure the stability of the output power and spectral (time and temperature stability).
3). To provide the same connection interface, and use the same type of fiber.
4). The size of the output power should meet the worst-case system loss measurements.

When the transmission systems require a separate stable light source, the optimal choice of light source should simulate the characteristics of the system Optical and measurement needs. When you select light source, it should be considered to the following aspects: a laser tube (LD) from the the LD light emitted from a narrow wavelength bandwidth, almost monochromatic, i.e. a single wavelength. Compared with the LED, through its spectral band (less than 5nm) the laser is not continuous, and on both sides of the center wavelength, but also the emission the several lower peak explants wavelength. Compared to the LED light source, laser source provides more power, but its price is higher than the LED. Laser tube is commonly used in the loss of more than 10dB of long-haul single-mode system. You should avoid measuring multimode fiber with laser light source.

Article source: FiberStore.com