Birefringent filter-based wavelength locker with high thermal stability

Athermalized birefringent filter-based wavelength locker using both material thermal compensation and temperature monitoring is presented. Frequency deviation is reduced less than 0.2GHz at a temperature range from 10°C to 40 °C for single-filter configuration. The dual-filter wavelength locker has uniform frequency resolution with frequency deviation less than 8GHz in a full FSR.