Apparatus for switching optical signals

Abstract

An apparatus for switching optical signals, comprising a first group of port cards adapted to receive input optical signals to be switched by the apparatus and a second group of port cards adapted to provide switched optical signals to an entity external to the apparatus. Each of the port cards in the first group includes a plurality of optical transmitter elements operative to produce respective optical beams from the input optical signals, as well as a transmit beam steering element array operative to orient the optical beams into respective transmit directions. Each of the port cards in the second group includes a plurality of optical receive elements operative to detect the presence of respective optical beams received from the port cards in the first group and produce respective ones of the switched optical signals therefrom. Application of beam steering at the port cards in the first group permits the apparatus to be more compact and allows for greater manufacturing tolerances.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS [0001] The present application is related in subject matter to two U.S. patent applications entitled “APPARATUS FOR REDIRECTING OPTICAL SIGNALS IN FREE SPACE” and “SYSTEM AND METHOD FOR CONTROLLING DEFLECTION OF OPTICAL BEAMS”, both to Alan Graves, both filed on the same date as the present application and both hereby incorporated by reference herein. FIELD OF THE INVENTION [0002] The present invention relates generally to optical communications and, more particularly, to an apparatus for switching optical signals. BACKGROUND OF THE INVENTION [0003] As optical signals used in optical communications carry ever increasing data rates according to an ever widening variety of data standards, it becomes desirable to provide switching at the photonic level, i.e., without resorting to electronic circuitry for converting the optical signals into the electrical domain before switching is performed. These types of optical switches are referred to as pho...

AI Technical Summary

Benefits of technology

[0010] In a specific embodiment, a controller may be associated to each particular one of the port cards in the first group. The controller is operative to control the transmit directions of the optical beams produced by the optical transmitter elements on the parti

Problems solved by technology

Generally speaking, first-generation photonic switches afford at most two of these benefits at the expense of the other(s) in packages compromised in size and cost due to the complex, usually fiber-guided, interconnect between the various modules of the switch.

This introduces inefficiencies in provisioning the switch.

Also, since optical signals are converted into the electrical domain for the purposes of wavelength conversion, switches of this type lose the designation of being truly photonic in nature.

Moreover, in lambda-plane switches, the optical interconnect requires up to thousands of individual optical fiber connections, which can be reduced in size somewhat by the provision of an orthogonal shuffle function, but this nevertheless results in a non-compact solution.

Other designs, such as multi-stage photonic switches (e.g., CLOS), can be made non-blocking through dilation or path rearranging, but do not scale well to accommodate an increase in the number of input signals.

In particular, the complexity of the interconnect between stages becomes intractable as the number of input signals increases.

Furthermore, in addition to introducing a delay, the multi-stage characteristic of these switches imparts a higher path loss due to multiple lossy switching operations in series that need to be compensated for in the design.

However, these switches tend to be large in size, have low tolerance to manufacturing error and also do not scale well due to a lack of modularity.

In addition, such switches have a complex fiber-based interconnect.

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