Quadrature-squeezed light generation with a fiber ring reflector (Invited Paper) [3211-37]

Norihiko Nishizawa, S. Kume, M. Mori +1 more

Norihiko Nishizawa

Masaki Hashirua, Norihiko Nishizawa, Masakazu Mori +1 more

Masakazu Mori, Norihiko Nishizawa, Toshio Goto

Hie generation and detection of quadrature squeezed states of light with a fiber ring reflector is reviewed. A 0.85µm polarization maintaining (PM) fiber is used as the nonlinear medium, and it is pumped by a 1.064µm mode-locked Nd:YAG laser. By the optical Kerr effect in the PM fiber, the input 1.064 mm light is squeezed. The combination of the smaller core diameter and the shorter source wavelength is effective in obtaining a higher peak power density, and consequently, a larger squeezing parameter at a low pump power. The squeezed vacuum is generated by combining the 50m long PM fiber ring with a 1:1 PM fiber coupler, and is detected by a balanced homodyne detector. The squeezed light noise is measured at 200kHz, and a squeezing parameter of 3.7dB is obtained at the input peak power of 5W. A simple calculation model based on the wave optics is used to estimate the squeezing parameter as a function of the input peak power. The calculated results agree well with the experimental ones. The squeezing in PM fibers is limited by the polarized guided acoustic wave Brillouin scattering (GAWBS), which is the phase noise originated from thermally induced fluctuations in the refractive index of the fiber. To avoid the noise due to GAWBS, a shorter PM fiber is preferable.

Norihiko Nishizawa, Satoshi Kume Satoshi Kume, Masakazu Mori +2 more

Efficient squeezing at low pump light power is demonstrated with a mode-locked 1.064 µm Nd:YAG laser and a fiber ring reflector made of 0.85 µm single-mode fiber. Noise reduction of about 2.0 dB below the shot noise level is observed. The squeezing process by the optical Kerr effect is calculated with a simple model. The experimental results are in good agreement with the calculated ones.

K. Bergman, H. A. Haus

A novel method of squeezing with optical pulses in a fiber ring reflector is demonstrated experimentally. Squeezing of greater than 5 +/- 0.3 dB has been observed. The pump is separated from the squeezed radiation with a fiber ring reflector and can be reused, in principle fully, as the local oscillator. The detection is at low frequencies (35-85 kHz) and is unaffected by guided-acoustic-wave Brillouin scattering.