Patent ID: 7164865
Filing Date: 2007-01-16
Classification: H01S

Abstract:
1. Optical-fiber communication equipment, comprising: a laser light source, a means for changing light of the laser light source to a parallel plane wave to form a parallel light path, an etalon having two or more transmission bands and having a free spectral range matched with a channel grid interval of wavelength division multiplexing optical-fiber communication, first and second light detecting means, wherein: said etalon is located in the parallel light path; a wavelength of the laser light source is enabled to be changed so that said wavelength is fixed to a desired value of the channel grid interval of wavelength division multiplexing optical-fiber communication; the parallel plane wave is divided into at least two pieces of light including light that is transmitted through said etalon and light passing through a medium and that has optical characteristics different from those of the light that is transmitted through said etalon; the first light detecting means detects one divided piece of light and the second light detecting means detects the other divided piece of light; signals based on photocurrents from the first and second light detecting means are compared to each other to obtain a signal for setting an emitting wavelength of the laser light source to a desired value; and said signal is used for controlling a wavelength of the laser light source, wherein said laser source and said etalon are located on the same Peltier cooler so that a temperature of said laser is changed in accordance with a temperature of said etalon, and a thickness of said etalon is greater than that of an etalon whose free spectral range is matched with a channel grid interval of wavelength division multiplexing optical-fiber communication without consideration of temperature dependence, so that a shifted quantity of said etalon caused by a temperature of said etalon becomes equal to a difference of a narrowed free spectral range and the channel grid interval, so as to bring the free spectral range of the etalon into match with the channel grid interval.