MULTIWAVELENGTH LIGHT SOURCE DEVICE EMPLOYING ANNULAR OPTICAL DELAY CIRCUIT

摘要

A multiwavelength light source device has a variable wavelength light source, a light intensity modulator, a photocoupler, an annular optical delay circuit and an optical gate device. The variable wavelength light source outputs output lights with a plurality of different wavelengths by switching them successively. The light intensity modulator subjects the output lights from the variable wavelength light source to amplitude modulation for a predetermined time and outputs the modulated signal lights. The photocoupler is optically connected to the light intensity modulator and receives the output lights from the light intensity modulator. The annular optical delay circuit is optically connected to the photocoupler and delays a part of the output lights from the light intensity modulator for a time longer than the predetermined time. The optical gate device is optically connected to the photocoupler, receives the output light from the light intensity modulator and a light through the annular optical delay circuit and opens its gate at such a timing and with such a time width as to include all the signal lights modulated for the predetermined time one each for each wavelength of the plurality of different wavelengths.