Single polarization, narrow linewidth hybrid laser based on selective polarization mode feedback

Linewidth Measurement of a Narrow-Linewidth Laser: Principles, Methods, and Systems

“…In 2019, F. Yang et al used a three-step parallel phase shift measurement method based on a 120° phase difference MI [114] to directly demodulate the accumulated laser differential phase within the delay time, derived the relationship between the differential phase and frequency noise and phase noise, and proposed a dynamic noise characterization method for narrow-linewidth sweep lasers based on phase reconstruction [79]. In 2022, X. Luo et al used a 120° phase difference interferometer to characterize the dynamic noise and differential phase information of a 1550 nm waveguide Bragg grating (WBG) ECDL via phase reconstruction [115]. The phase/frequency noise power spectral density of the laser can be obtained by the β isolation line algorithm, with a minimum In 2022, X. Luo et al used a 120 • phase difference interferometer to characterize the dynamic noise and differential phase information of a 1550 nm waveguide Bragg grating (WBG) ECDL via phase reconstruction [115].…”

“…In 2022, X. Luo et al used a 120° phase difference interferometer to characterize the dynamic noise and differential phase information of a 1550 nm waveguide Bragg grating (WBG) ECDL via phase reconstruction [115]. The phase/frequency noise power spectral density of the laser can be obtained by the β isolation line algorithm, with a minimum In 2022, X. Luo et al used a 120 • phase difference interferometer to characterize the dynamic noise and differential phase information of a 1550 nm waveguide Bragg grating (WBG) ECDL via phase reconstruction [115]. The phase/frequency noise power spectral density of the laser can be obtained by the β isolation line algorithm, with a minimum integrated linewidth of 4.36 kHz and a minimum Lorentz linewidth of 3.58 kHz, as shown in Figure 10d.…”

“… ( a ) Laser frequency noise measurement using a frequency discriminator, which is an unbalanced Mach–Zehnder interferometer [ 105 ]; ( b ) COSH setup: A laser is split by a three-port AOM into frequency-shifted (1st-order output) and unshifted (0th-order output) portions [ 109 ]; ( c ) 3 × 3 fiber coupler unbalanced Michelson interferometer self-heterodyne technique [ 113 ]; ( d ) Measured FN-PSD spectrum with narrowest linewidth [ 115 ]. …”

“…In 2022, X. Luo et al used a 120° phase difference interferometer to characterize the dynamic noise and differential phase information of a 1550 nm waveguide Bragg grating (WBG) ECDL via phase reconstruction [ 115 ]. The phase/frequency noise power spectral density of the laser can be obtained by the β isolation line algorithm, with a minimum integrated linewidth of 4.36 kHz and a minimum Lorentz linewidth of 3.58 kHz, as shown in Figure 10 d. In 2023, this team utilized a nonequilibrium MI system to measure the linewidth of an ECDL in 1 μm band [ 116 ] and used the β-isolation line integration algorithm to derive and evaluate linewidth in different Fourier frequency domain ranges, resulting in a minimum integrated linewidth of 25.60 kHz and a minimum Lorentz linewidth of 12.00 kHz.…”

Research Progress of Wide Tunable Bragg Grating External Cavity Semiconductor Lasers

“…The results showed that the minimum linewidth of the WBG was 0.1 nm, the maximum SMSR was 13.2 dB, and the maximum reflectance was 99%. In the same year, Luo et al [94] reported a narrow linewidth hybrid laser based on a SL gain chip and birefringent silicon WBG. The optimal linewidth was 4.36 kHz and the output power was 6.53 mW.…”