These lamps can be used without coupling optics.

Miniature incandescent lamps of a special type have been invented to satisfy a need for compact, rapid- response, rugged, broadband, power- efficient, fiber-optic- coupled light sources for diverse purposes that could include calibrating spectrometers, interrogating optical sensors, spot illumination, and spot heating. A lamp of this type (see figure) includes a re-entrant planar spiral filament mounted within a ceramic package heretofore normally used to house an integrated-circuit chip. The package is closed with a window heretofore normally used in ultraviolet illumination to erase volatile electronic memories. The size and shape of the filament and the proximity of the filament to the window are such that light emitted by the filament can be coupled efficiently to an optical fiber without intervening optics.