Method to tune emission wavelength of semiconductor laser diode

摘要

A method to tune an emission wavelength of a laser diode (LD) finely is disclosed. The method first controls a temperature of the etalon filter in T1 or T2, where the transmittance of the etalon filter becomes 40 to 50%, assuming a height between the peak and the bottom of the periodic transmittance to be 100%, at the grid wavelength λ1 or λ2, respectively. Then, the temperature of the LD is adjusted such that the intensity of light emitted from the LD and transmitted through the etalon filter becomes 40 to 50%.

主权项

1. A method to tune an emission wavelength of a wavelength tunable laser diode (LD) to a target grid wavelength by using an etalon filter showing a periodic transmission spectrum with a plurality of peaks and bottoms alternately appearing with a constant period, the periodic transmission spectrum of the etalon filter having a period between two peaks nearest to each other substantially twice of a span between two grid wavelengths nearest to each other, the method comprising steps of:
determining a preset temperature of the etalon filter such that, as varying the temperature of the etalon filter, the transmittance of the etalon filter becomes greater than 40% relative to a height between a peak and a bottom at two grid wavelengths, wherein the transmission spectrum of the etalon filter has signs in a first derivation thereof same to each other at the two grid wavelengths; setting the etalon filter in the preset temperature such that the etalon filter shows a target transmittance greater than a reference transmittance by which the periodic transmission spectrum of the etalon filter shows a span substantially equal to a span between the two grid wavelengths neighbor to each other; and setting the wavelength tunable LD in a target temperature such that light emitted from the tunable LD and transmitted through the etalon filter shows the target transmittance.