Narrow-linewidth and highly stable optical frequency comb realized with a simple electro-optic modulator system in a mode-locked Er:fiber laser

Abstract

We demonstrate a mode-locked Er:fiber laser with a compact fiber-pigtailed optical bench containing a free-space electro-optic modulator for highspeed feedback control. The achieved servo bandwidth of the beat frequency between a given comb component and a reference laser is approximately 850 kHz. The realization of a narrow-linewidth and highly stable frequency comb is confirmed by measuring both in-loop and out-ofloop beat frequencies. We also demonstrate the frequency measurement of two iodine-stabilized Nd:YAG lasers through the narrow-linewidth comb without stability degradation. The developed optical frequency comb can work continuously for weeks without maintenance.

Offset-locking-based frequency stabilization of external cavity diode lasers for long-distance quantum communication

“…4(c), the light blue dots indicate the Allan standard deviation of the iodine-stabilized 1010 nm laser, which is measured using the narrow-linewidth comb. 19) The frequency stability was 9.1 × 10 -13 (corresponding to an absolute frequency of 0.27 kHz) at τ = 1 s and 6.8 × 10 -13 (0.20 kHz) at τ = 155 s, respectively. Locking was achieved to the a2 hyperfine transition of the P(41)56-0 line, as illustrated in the inset of Fig.…”

“…To confirm the actual stability of the offset-locked laser, we also performed an out-of-loop signal measurement [red dashed line in Fig. 3(c)] using another OFC which is phase-locked to an iodine-stabilized Nd:YAG laser (narrow-linewidth OFC) 19) and has a much higher stability than that of the GPS-OFC. The stability of the out-of-loop signal indicates the stability of the offset-locked 1514 nm laser and is 3.6 × 10 -12 (corresponding to an absolute frequency of 0.71 kHz) at τ = 1 s and 2.7 × 10 -11 (5.4 kHz) at τ = 287 s, respectively.…”

Precision spectroscopy of iodine absorption lines near the 1S0-3P2 transition of Yb atoms at 507 nm

“…The fundamental laser beam was sent to an optical frequency comb for beat-frequency measurements. The optical frequency comb was an erbiumdoped fiber comb with an iodine-stabilized Nd:YAG laser as the frequency reference 21) . The beat signal observed by the photodetector (PD2) was measured using a dead-time-free frequency counter (Pendulum: CNT-91).…”

“…4(a) as a black dashed line. 21) As the frequency comb is more stable than the developed iodine-stabilized laser, the observed Allan standard deviation (red solid curve with solid circles) indicated instability of the developed laser. The solid blue curve with solid circles in Fig.…”

Transfer of linewidth and frequency stability from an iodine-stabilized Nd:YAG laser to a quantum memory control laser through an optical frequency comb

“…17) In this study, waveplates and a polarizer on an optical bench are used to realize simple and durable laser mode locking. 18) A free-space electro-optic modulator (EOM, Thorlabs EO-PM-NR-C) is also placed on the optical bench for the high-speed control of the laser cavity length. The dynamic range of the cavity length control is extended by using a piezoelectric element attached to the optical fiber in the laser and a Peltier element that controls the temperature of the laser cavity.…”