Fully provisioned 112×112 micro-mechanical optical crossconnect with 35.8 Tb/s demonstrated capacity

Abstract

Transparent optical crossconnects provide a substantial advantage relative to electronic crossconnects during this time when optical networks are characterized by rapidly increasing data rates and evolving data formats. The dramatic expansion of network size and capacity requires these optical crossconnects to be scalable to large port counts, N>1000. Consequently, any practical technology should have the number of active components scale with the port count, NI and not the number of connections, N2. The insertion loss should also be uniform across the switching fabric and independent of N. These considerations preclude the use of cascaded small switches if a strictly non-blocking architecture is to be maintained. Largescale integration of active devices as is practical with (Micro-ElectroMechanical System) technology, has the potential of lowering the cost per port as fabrics grow in size. The applications for large optical switch matrices are in network management where load balancing and traffic routing can be achieved. They also provide additional network robustness by offering comprehensive protection switching and restoration. In the longer term they are critical to Optical Networking: building end-to-end transparent networks. In this paper we present results from a fully provisioned 1 12x1 12 micro-mechanical optical cross connect in which all 12544 connections have been verified. The cross connect function is achieved using two-axis beam steering micro-mechanical mirrors which are electrostatically actuated [1,2] and illustrated in figure 1 and figure 2. The system consists of a 2 0 array of MEMS mirrors, a fiber array with a collimating microlens array and a fold mirror to allow one MEMs array and lendfiber array to be used for both input and output. The components are mounted in a mechanical housing as shown in figure 3-the characteristic dimension of the fabric is 1 Ocm. A cross connect path, which is illustrated in figure 4, consists of light leaving one fiber and being collimated and projected onto a MEMS micro-mirror by a microlens. The first micro-mirror tilts so as to direct the beam off the fold mirror onto a second micro-mirror. The second micro-mirror tilts so as to direct the light towards a microlens where it is coupled into the output single-mode fiber. This system is optically equivalent to a system unfolded about the fold mirror, which if constructed, would use an additional MEMS mirror array and lendfiber array, resulting in a 224x224 optical crossconnect. This beam steering configuration is attractive for building large optical crossconnects since the number of mirrors in the system is equal to twice the number of ports, 2N, and not the complexity of the crossconnect. Typical connection switching time is c l Oms, including the drive-voltage risetime. Insertion loss of the optical fabric is 7.5+2.5dB in the minimum loss region around 1550nm. The diffractive microlenses of the lendfiber array were designed for use in the 1525-1 565nm wavelength band resulting in a connection loss variation...

Micro-optical fiber switch for a large number of interconnects using a deformable mirror

“…Alignment tolerances, diffraction of the Gaussian beams, and aberrations are parameters which are more critical for optical switches with large number of interconnects than for optical switches with a few interconnects. Most of the published optical switches with large number of interconnects are using micromirrors with sizes in the range of 100-500 m [3]- [5]. These switches have relatively small collimated beams, which in the case of two-dimensional (2-D) micro-electro-mechanical system (MEMS) optical cross-connect, limit their expandability due to diffraction [6].…”

Free-Space Optical MEMS

“…With an increasing number of wavelengths and bandwidth in dense wavelengthdivision-multiplexed (DWDM) networks, there is a need for optical crossconnect (OXC) with a large port count. [14][15][16] The dual-axis analog scanning capability is key for these applications since each mirror associated with the input fiber array can point to any mirror associated with the output fiber array. Implementation of N × N OXC using two arrays of N analog scanners is illustrated in Fig.…”

Optoelectronic router with a reconfigurable shuffle network based on micro-optoelectromechanical systems

“…Reports show that 112  112 switches with the capacity of 35.8 Tbit/s are possible and reliable [19]. Agilent announced a fully non-blocking 32  32 switch in March 2000 [20] and Lucent Technologies announced a 238  238 switches based on the 3-dimensional MOEMS technology with 56 644 possible connections [21], while switch sizes of 1024  1024 are prototyped and 4096  4096 port MEMS are considered to be reality in the next few following years.…”