Generation of 2 THz Span Optical Comb in a Tunable Fiber Ring Based Optical Frequency Comb Generator

The generation of a 2 THz span optical comb, defined within a 10 dB power envelope and consisting of 200 optical comb lines, all stronger than -20 dBm without amplification, is reported. The effective transmittance of the generator is 11.5 dB. The comb line spacing can be adjusted with a step frequency that equals an integer multiple of 12.500 MHz while maintaining the comb profile. High coherence between the comb lines is achieved, with the bent signal between the comb lines having a noise level of -92 dBc/Hz at 1 kHz offset, and phase noise of -130 dBc/Hz at 1 MHz offset.