Frequency Stabilization Of Laser Diode Research Articles

Influence of thermal effects in microresonators on the locking range in self-injection locking of laser diodes

Stable narrow-linewidth lasers generated by self-injection locking systems have revolutionized applications from optical frequency metrology to astronomy. However, the dynamics for the self-injection locking system are intrinsically intertwined with thermal effects, which can generate a nonnegligible resonance drift in the microresonator and result in large detuning from the required regime. In this paper, we introduce the thermal effect, depending on the photon number, into self-injection locking systems with Rayleigh backscattering. We obtain a set of time-domain rate equations to describe the dynamics of laser-diode–cavity–microresonator systems and derive analytical formulas for effective detuning. The analytical results match well with our numerical simulations, and the effective detuning locking position moves forward as the value of the thermal effect coefficient decreases. We also analyze the dependence of the locking range and stable range on thermal effects, and our calculations show that, based on our approach, the stable range can be optimized effectively and the locking range is extended. Our results have the potential to optimize laser diode frequency stabilization experiments.

Laser diode frequency stabilization bases on Iodine saturated absorption and sinusoidal phase modulation with suppression of residual amplitude modulation

Laser diode frequency stabilization bases on Iodine saturated absorption and sinusoidal phase modulation with suppression of residual amplitude modulation

Sinusoidal frequency modulation for frequency stabilization of laser diode to an I2 saturated absorption line and a displacement measuring interferometer

Sinusoidal frequency modulation for frequency stabilization of laser diode to an I2 saturated absorption line and a displacement measuring interferometer

Sinusoidal phase modulation for frequency stabilization of laser diode and displacement measuring interferometer.

Sinusoidal phase modulation for frequency stabilization of laser diode and displacement measuring interferometer.

Laser diode frequency stabilization with a fiber ring resonator

To improve the frequency stabilization of laser diode in the laser frequency scanned interferometric metrology, a modified method is proposed by using a fiber ring resonator. The theoretical analysis of this modified method is performed. Moreover, the Pound-Drever-Hall (PDH) technique is employed to obtain the frequency discrimination curve of a fiber ring resonator, whose finesse is 1260 and line-width is 270 kHz. The simulated results show that the curve has a steep slope near the resonant frequency, which proves the sensitivity of this system to the frequency deviation, so the modified method has great potential for the frequency stabilization of a laser diode.

Formulation of frequency stability limited by laser intrinsic noise in feedback systems

We investigated the influence of amplitude modulation (AM) noise and phase modulation (PM) noise of a laser source on the frequency stability in frequency stabilization systems. We estimated the frequency stability and evaluated the efficacy of a noise reduction technique (the Doppler-trend subtraction method) of a laser diode frequency stabilization system, where enhanced intensity noise arising from PM-to-AM noise conversion through a reference gas cell is reduced using the technique employed in modulation transfer spectroscopy. To evaluate the relationship between the laser's intrinsic noise and its frequency stability, we performed noise spectrum measurements and formulated frequency stability in addition to measuring Allan standard deviation. As a result, it is found that the extra noise generated in PM-to-AM conversion is efficiently removed by the Doppler-trend subtraction method and that within the feedback bandwidth, the frequency stability becomes 1 order of magnitude better than that without the method.

Excitonic transitions in Si δ-doped GaAs studied with wavelength modulated lateral photoconductivity

The New Photothermal Wavelength Modulated Photocurrent (PTWMPC) technique was recently used and demonstrated as a simple method for studying the excitonic transitions under the bandgap in Si δ-doped GaAs. The spectroscopic aspects of PTWMPC have been theoretically and experimentally studied. The PTWMPC phenomena and the nature of registered features are explored in details. The PC spectrum line shape, the full width at half-maximum intensity dependence, the chopping frequency and the excitonic peaks position intensity dependence are discussed. The PTWMPC can be proposed as a simple external resonator optoelectronic technique for laser diode frequency stabilization and the Si δ-doped GaAs cell is useful as a device with sharp reference frequency absorption peaks for metrological purposes.

Frequency Stabilization Based on Attenuated Fiber Loop Resonator (AFLR)

A new device ― Attenuated Fiber Loop Resonator (AFLR) ― for frequency stabilization is proposed. The AFLR simply includes a variable intensity attenuator in a fiber loop which can be tuned to achieve the best frequency stabilization condition. We derive the transmission function of AFLR by improving the matrix model which now includes intrinsic fiber loss in the fiber loop and coupling loss in the fiber coupler. The relation between coupling coefficient and loop transmission is also analyzed. Two new laser diode frequency stabilization schemes using AFLR are proposed and the optimum operating conditions are obtained. Simulation results also show that the coupling loss which degrades the transmission response of AFLR is detrimental to frequency stabilization

Frequency stabilization of laser diode using a frequency-locked ring resonator to acetylene gas absorption lines

The frequency stabilization of a 1.5 mu m distributed-feedback (DFB) laser diode using a planar lightwave circuit (PLC) ring resonator whose resonant frequency is locked to /sup 12/C/sub 2/H/sub 2/ and /sup 13/C/sub 2/H/sub 2/ gas absorption lines is described. The resonant frequency of PLC ring resonator was stabilized within a 5 MHz peak-to-peak fluctuation. With this ring resonator the outer frequency fluctuation of the DFB laser diode was stabilized within 10 MHz at every resonant frequency at 5 GHz intervals. The stability demonstrated is as good as the method using molecular absorption lines as a reference. The stabilized frequency can be selected at any point on the optical resonant peaks of the optical resonator. >

Frequency stabilization of laser diodes at 0.83 mu m using a fiber optic coupler

Frequency stabilization of a fiber pigtailed laser diode discriminator is reported. The fiber coupler acts as a nearly-balanced-arm Michelson interferometer. The peak transmission signal is used for feedback control of the injection current of the laser diode. Because the sensing port can be isolated from the signal transmission port, the package design is very simple and can be implemented in an all-fiber fashion. The frequency fluctuation of a 0.83- mu m test laser stabilized by this method is less than +or-4 MHz. This scheme is applicable to longer-wavelength (1.2-1.6 mu m) laser diodes; the stabilized lasers can be packaged easily. >

Rb吸収線を用いた無変調出力の半導体レーザ周波数安定化

Rb吸収線を用いた無変調出力の半導体レーザ周波数安定化