Fig. 1. (Color online) Schematic of the proposed TS-DFB laser.

Fig. 2. (Color online) (a) Schematic of the SBGs in TS-DFB lasers. (b) Reflection and transmission spectra of SBGs in different sections. (c) Threshold gain and threshold gain margin versus the length of the grating reflector.

Fig. 3. (Color online) The principle of the detuned loading effect in TS-DFB lasers. Circles represent the main mode.

Fig. 4. (Color online) Calculated small-signal modulation response of the TS-DFB laser and OS-DFB laser.

Fig. 5. (Color online) (a) Measured spectra of the eight-channel TS-DFB laser array (I₁ = 70 mA, I₂ = 25 mA). (b) The corresponding lasing wavelengths of laser arrays (dots). The linear fitting line of wavelengths, and the residuals after fitting.

Fig. 6. (Color online) Light-current characteristics of (a) the TS-DFB laser array and (b) the TS-DFB laser with different current I₂.

Fig. 7. (Color online) (a) Light-current characteristics with different temperatures when I₂ is 25 mA. (b) Corresponding threshold current and slope efficiency.

Fig. 8. (Color online) Measured SMSRs and lasing wavelengths. (a) I₁ = 50−100 mA, I₂ = 20 mA and (b) I₂ = 0−25 mA, I₁ = 70 mA.

Fig. 9. (Color online) (a) Measured spectra at different temperatures when I₁ is 70 mA and I₂ is 20 mA. (b) The corresponding SMSRs and lasing wavelengths.

Fig. 10. (Color online) (a) Photo of the TS-DFB laser on the carrier. (b) Experimental setup schematic for the measurement of dynamic characteristics. EDFA: erbium-doped fiber amplifier, OSC: oscilloscope, DC: direct-current power source, BERT: bit error rate tester, VNA: vector network analyzer, PD: photodetector.

Fig. 11. (Color online) Small-signal modulation response of the TS-DFB laser. (a) I₁ = 60−100 mA, I₂ = 25 mA. (b) I₂ = 0−25 mA, I₁ = 100 mA.

Fig. 12. (Color online) Measured chirp parameters at different currents.

Fig. 13. (Color online) Eye diagrams under 10 Gb/s direct modulation after back-to-back (BTB) and 5 km single mode fiber transmission. (a) BTB, I₂ = 0 mA. (b) BTB, I₂ = 25 mA. (c) 5 km, I₂ = 0 mA. (d) 5 km, I₂ = 25 mA.

Fig. 14. The measured BER under 10 Gb/s NRZ modulation when I₂ is 25 mA.