Optical Switching Systems Research Articles

Optical Switching System Experiment

The construction and experimental results of a tiny optical video switching system are described. It had a 4 × 3 switch network composed of seventeen 1 × 2 type meehanical optical fiber switches whose average loss was 2.6 dB. Network insertion loss was about 20 dB. Insertion loss cause, signaling method and improvement for practical use are discussed.

Moving optical-fiber switch experiment

The switch uses a V-grooved connecting device. The mechanism is suitable for a large switch, which is desirable for an optical switching system. A moving fiber is inserted into one of the radially arranged V grooves using the elastic bending force as the drive current. The insertion condition, which realizes stable connection and high durability, is discussed. Switch structure and experimental results are described. Insertion loss was 0.33 dB, and the variation in transmissivity was 3%.

Optical waveguide switch (3 × 3) for an optical switching system

A new optical switch element is proposed for a switching system which exchanges optical signals in optical transmission lines without optoelectric conversion. It consists of three parallel equidistant straight singlemode waveguides fabricated of an electrooptic material with electrodes deposited on them. The element, whose interaction length is pi/(2)((1/2))k (k is the coupling coefficient of neighboring guides), serves as a 3 x 3 optical switch by control of the differences in propagation constants between those waveguides. Control conditions to realize all the six connecting states of a 3 x 3 switch are discussed with the solution of the coupling equation for those guides.

Fully Electronic Space-Division Telephone Exchanges Using Semiconductor Crosspoints and Optical Switching

The state of the art in fully electronic space-division telephone exchanges shows that neither can semiconductor crosspoints directly replace reed relay contacts in Public exchanges, nor can hitherto semiconductor switching networks compete with reed relay switching networks. Though semiconductor crosspoints fulfill all transmission requirements, they are too expensive. Investigations on this field by the authors led to the following results. 1) A semiconductor crosspoint with high breakdown voltage and low on-resistance has been developed. This crosspoint can be connected to a subscriber's line and thus directly replace a reed relay in a public exchange at only slightly higher cost. 2) These crosspoints with high voltage capability can be combined with low cost, low breakdown voltage MOS semiconductor arrays in large-scale integration (LSI) techniques which are isolated from the subscriber lines by transformers to form a fully electronic switching network. 3) A crosspoint free of on-attenuation which can be monolithically integrated to crosspoint arrays has been developed; 4) A thick-film hybrid crosspoint for switching of commercial high-resolution video signals has been developed. The state of the art of optical switching systems shows that switching networks using a laser beam enable the transmission of wideband video signals with comparatively high crosstalk attenuation.