Fig. 1. Diagram of proposed spectrometer based on quasi Littrow structure

Fig. 2. (a) Light intensity distribution and line spread intensity distributions in (b) X direction and (c) Y direction of spots on plane of middle slit

Fig. 3. Light intensity distribution on plane of exit slit. (a) Light spot distribution; (b) wavefront distribution; (c) geometric encircled energy

Fig. 4. Flow chart of photoelectric signal processing of self-developed photoelectric detection system

Fig. 5. Diagram of experimental system

Fig. 6. Recovery spectra with highest resolution of laser with different wavelengths. (a) Wavelength of 1550 nm; (b) wavelength of 1310 nm

Fig. 7. Recovery spectra of laser with wavelength of 1550 nm at different resolutions.(a) Resolution of 0.1 nm; (b) resolution of 0.5 nm; (c) resolution of 1 nm

Fig. 8. Spectrum of low noise laser with wavelength of 1550 nm