Optical eraser and node switch for an optical network

DETAILED DESCRIPTION FIG.
1 is a cross sectional view of an optical energy eraser 10 suitable for use in an optical network in accordance with one aspect of this invention.
The eraser comprises a sleeve 11 having an internal surface 12.
The vertical dimension of sleeve 11 as viewed in the figure, is relatively small to bring top and bottom portions of surface 12 into closely spaced apart positions.
The top portion includes longitudinal slot 14 in which optical fiber 15 is secured.
A relatively large volume quartz block 16 is fixed in position opposite fiber 15 as shown in the figure.
Fiber 15 is shown as having a relatively large core 17 (diameter=100 microns) and a cladding 18 (diameter=140 microns) shown absent in the area opposite block 16.
The sleeve includes an open area 19 which, in the illustrative embodiment includes a liquid with an index of refraction equal or less than that of cladding 18.
The sleeve is sealed at both ends in a manner to contain the liquid yet permit fiber 15 to extend beyond the sleeve.
The sleeve is supported by a rigid support member 25 to which rigid bridge 26 also is secured.
Pressure element 27 is suspended from bridge 26 and is adapted to apply pressure to the sleeve in a manner to move fiber 15 and block 16 towards one another.
Initially, fiber 15 is on the order of forty microns from block 16.
When pressure element 27 applies pressure to the sleeve, fiber 15 is moved into contact with block 16.
Element 27 conveniently comprises a piezoelectric element operative to apply eight to sixteen oounces of force against sleeve 11 in response to a command signal.
Control circuit 30 is operative to apply such a (steady state) voltage to element 27 to produce the force when required.
Eraser 10 is utilized conveniently with switches disclosed in copending application Serial No.
750,805.
FIG.
2 shows such an arrangement in which the positions of an eraser 30 and first and second sleeve switches 31 and 32 share a common support member 34.
Separate pressure elements (not shown in FIG