Led stabilized light source

Abstract

Abstract PURPOSE:To output a stable light immediately after a power source is turned ON by providing a single mode fiber coupler for branching the light of an LED to output one branched light outward thereby to introduce the other branched light to a photodetector, and a feedback loop for feeding back the output of the photodetector to an LED driving circuit. CONSTITUTION:The output light of an LED 1 is incident to an incident side single mode fiber 4 of a single mode fiber coupler 3. A light incident to the fiber 4 is branched to two single mode fibers 5, 6 of the emitting side. The light of the fiber 5 is externally output, and the light of the fiber 6 is introduced to a PD (photodiode) 7 of a photodetector. After the output signal of the PD 7 is first amplified by a preamplifier 8, it is fed to a comparator 9, which compares it with a reference voltage. A driving circuit 2 is controlled by the output of the comparator 9 generated as the compared result, and the driving current of the LED 1 is varied to form a feedback loop.

Inventors

• 👤 Yoshiharu Unami
• 👤 宇波　義春
• 👤 Masao Tanaka
• 👤 正夫 田中

Bibliographic Details