In order to realize non-blocking switching and adding/dropping of wavelengths, the new generation of ROADM nodes are required to be colorless, directionless and contentionless (CDC ROADM). The following are five types of ROADM structures. The focus is on how they support CDC functions. Fig.2 shows ROADM structure #1. The NNI is constructed with 1×N WSSs. The number of WSSs for a M-dimensional ROADM is 2M. The figure shows only three dimensions. The UNI includes several add/drop modules (the figure shows only two of them). Each add/drop module has two 1×N WSSs linked back-to-back for signal dropping and a 1×N WSS linked to a power splitter for signal adding. According to the function of 1×N WSS, the ROADM structure can support colorless and directionless add/drop of signals. However, when the dimension of the ROADM node is more than the number of add/drop modules, contention happens at the links in the red circle. Maybe we can add the add/drop modules. But the cost is not cheap. Thus this ROADM structure is defined as a CD ROADM and doesn’t meet the CDC requirement. Read more from HYC Blog, <The Structures of ROADM>
... View more
Optical switches are widely employed in optical fiber communication systems. MEMS optical switches are characterized by compact size, low power consumption and good scalability, which enable their wide applications. According to the difference in port configurations, different MEMS chips are employed for realization of the devices. This article will discuss optical switches with 2×2 and 1×N ports. HYC Technical blog. http://optical-passive.com/
... View more
thanks for your kind remarks.
About the MCS optical switches:
they work without using micromirrors like the MEMS do.
According to the following document :
>> The complex crisscrosses between the top-layer splitters and bottom-layer switches indicate the real need for a photonic integrated circuit, i.e., a planar lightwave circuit (PLC) based on a silica-on-silicon chip. MCSs based on PLC are not only more suited for mass production than other technologies such as MEMS, but can also offer the advantage of small and compact size.
The documents also mention that in MCS erbium doped fiber optical amplifiers may be used to improve output power level (to compensate for power loss caused by splitting).
These MCS are actually more complex as they are classified as Optical Add Drop Multiplexer O ADM.
They are able to operate OADM at optical wavelength level:
>> In Fig.1, the traffic is from or to 8 directions. Any one of the 80-96 wavelengths in a particular direction can be dropped to or added from any one of the 16 output or input ports. How this is achieved can described as follows.
Hope to help
... View more
A fiber optic reflector is an optical passive device constructed in a short segment of optical fiber that reflects particular wavelengths of light and transmits all others that are not within the specific reflection wavelength range. Common types include adapter type and pigtail type. HYC's SC reflector is a kind of reflector based on SC connector package. SC/APC and SC/PC interfaces are available. The reflector for 1650 nm reflects all wavelengths from 1645 nm to 1655 nm. With its low insertion loss at the transmission wavelength range and high reflectance at the reflected wavelength range it is the ideal optical termination for link monitoring of FTTx networks , FTTx reflectors are suitable for both point to point (PTP) and point to multipoint (PTMP) networks. They are preferably installed at the subscriber’s homes in order to highlight these positions in the OTDR trace by distinct reflections of the test signal. HYC SC reflector has a transmission wavelength (1260~1625nm), high reflectivity, low insertion loss (≦1.4dB), high return loss (≧35dB),compact design and more features. Application: 1.Create high reflectance at the termination of a PON without disturbing traffic 2.Test reflectance from the central office 3.Check optical continuity of subscriber when being added or when troubleshooting With the implementation of the fiber-to-the-home (FTTH) project, the coverage of the optical network is getting larger and larger, involving more and more users. Therefore, it is particularly important to detect and maintain the fault of the entire optical network quickly and accurately. Fiber optic reflector will be widely used in FTTx network, PON OTDR test, central office reflectivity test, communication system link detection and so on.
... View more