Fully self-referenced frequency comb consuming 5 watts of electrical power

Abstract

We present a hybrid fiber/waveguide design for a 100-MHz frequency comb that is fully self-referenced and temperature controlled with less than 5 W of electrical power. Selfreferencing is achieved by supercontinuum generation in a silicon nitride waveguide, which requires much lower pulse energies (~200 pJ) than with highly nonlinear fiber. These lowenergy pulses are achieved with an erbium fiber oscillator/amplifier pumped by two 250-mW passively-cooled pump diodes that consume less than 5 W of electrical power. The temperature tuning of the oscillator, necessary to stabilize the repetition rate in the presence of environmental temperature changes, is achieved by resistive heating of a section of goldpalladium-coated fiber within the laser cavity. By heating only the small thermal mass of the fiber, the repetition rate is tuned over 4.2 kHz (corresponding to an effective temperature change of 4.2 °C) with a fast time constant of 0.5 s, at a low power consumption of 0.077 W/°C, compared to 2.5 W/°C in the conventional 200-MHz comb design.

Compact mode-locked Er-doped fiber laser for broadband cavity-enhanced spectroscopy

“…The rms of the noise is < 0.42 mHz demonstrating the excellent relative stability of the repetition frequency in long term operation. We did not use the metal-coated fiber in the f rep lock, however, it might be successfully used for simple and low-power thermal stabilization of a mode-locked oscillator, as shown in [7].…”

“…Operation outside the laboratory requires compact, low-cost and low power consumption comb sources, which are enabled by the use of fiber-based technology [5,6]. Recently a fully self-referenced frequency comb based on an Er-doped fiber laser was reported, with electrical power consumption of only 5 W [7]. It has been also proven that fiber-based frequency combs are ready for space travel and resistant to microgravity conditions [8].…”

Broadband supercontinuum generation in nitrogen-rich silicon nitride waveguides using a 300 mm industrial platform

“…On the other hand, a silicon nitride (SiN x ) platform is compatible with silicon technology and offers a nonlinear index 10 times higher than that of silicon dioxide with negligible TPA in the near-infrared wavelength range [16]. Hence, in the last decade, multiple studies have demonstrated wide SCG in SiN x waveguides featuring broadband spectra [17][18][19][20][21][22][23][24][25][26][27][28][29]. Applications of supercontinuum in SiN x have been shown with, for example, an f -to-2f interferometer for carrier envelope offset frequency detection [21,24,[30][31][32], or mid-infrared generation of dispersive waves (DWs) for gas spectroscopy [28].…”

20 years of developments in optical frequency comb technology and applications

“…The latter fiber lasers, built with off-the-shelf all-fiber components, allowed for even more compact, energy efficient and robust systems. Subsequently these Er:fiber OFCs have seen the most commercial success and are the most commonly used OFCs system to date 15,[38][39][40][41][42] . Other notable fiber lasers include the high power 1 μm Yb:fiber 43 , which when combined with high power Ytterbium amplifiers are ideal candidates for high-harmonic generation in the XUV for direct comb spectroscopy 44 , as well as the realization of 2 μm Thulium doped fiber-OFCs 45 .…”

“…OFCs quickly found application to a multitude of diverse optical, atomic, molecular, and solid-state systems, including X-ray and attosecond pulse generation 4 , coherent control in field-dependent processes 5,6 , molecular fingerprinting 7 , trace gas sensing in the oil and gas industry 8 , tests of fundamental physics with atomic clocks 9 , calibration of atomic spectrographs 10 , precision time/frequency transfer over fiber and free-space 11 , arbitrary waveform measurements for optical communication 12 , and precision ranging 13 . To support this broad application space, OFCs have seen rapid changes in laser development to enable coverage at different spectral regions, varying frequency resolutions, and to enable the development of systems that offer lower size, weight and power (SWAP) [14][15][16][17] .…”