Patent ID: 9680284
Date: 2017-06-13
CPC Classifications: G02F,H01S,H04B

Claim:
1. A device for lessening a dependence of a spectral characteristic of a light source on temperature, comprising: a first polarizer having a polarization axis oriented in an X-direction, for polarizing an input optical beam to obtain a first optical beam having a polarization oriented in the X-direction; a first polarization rotator optically coupled to the first polarizer and configured for rotating the polarization of the first optical beam away from the X-direction by a first angle having a pre-defined dependence on temperature, such that the polarized optical beam comprises an X-polarization component oriented in the X direction, and a Y-polarization component oriented in a Y-direction perpendicular to the X-direction; a first waveplate optically coupled to the first polarization rotator and having an optical axis oriented substantially in the X-direction or Y-direction, for imparting a non-zero phase shift between the X- and Y-polarization components of the first optical beam; a second polarization rotator optically coupled to the first waveplate and configured for rotating the X-polarization component of the first optical beam by the first angle back to become oriented in the X-direction and having a substantially same pre-defined rotation angle dependence on temperature as the first Faraday rotator; and a second polarizer optically coupled to the second polarization rotator having a polarization axis oriented in the X-direction, for polarizing the first optical beam to obtain an output optical beam; wherein a coupling efficiency of the first optical beam into the output optical beam has a wavelength dependence due to the non-zero phase shift between the X- and Y-polarization components of the first optical beam; wherein an amplitude of the wavelength dependence is dependent on the first angle and thereby has a pre-defined dependence on the temperature.