Optical amplifier

About: Optical amplifier is a research topic. Over the lifetime, 32962 publications have been published within this topic receiving 416254 citations.

Optical time-domain reflectometry apparatus

Abstract: An optical time domain reflectometry (OTDR) apparatus uses Raman scattering light as a light source. A light pulse having a high intensity generated from laser diode pumped solid state laser (11) is launched into optical fiber (12) from its one end to generate induced Raman scattering. The induced Raman scattering light emitted from the other end of optical fiber (12) has a wide spectrum of wavelengths with strong intensity. Thus obtained induced Raman scattering light is introduced into optical fiber under test (9) from its one end. Subsequently, the backward scattering light returning to the aforementioned one end is taken out by means of optical coupler or optical switch (3) to brought into optical detectors (5), which, in turn, detects the light so as to be measured on the intensity of the particular wave components by every period of time by means of digital averaging circuit (7) and computer (8).

Solid state fiber optic semiconductor ring laser apparatus

Abstract: A high power solid state semiconductor fiber optic ring laser which includes an optical amplifier diode having its waveguide region oriented at an angle between Brewster's angle and 0° with respect to the normal to the diode cleavage planes together with antireflection coatings disposed on the diode cleavage planes. The optical amplifier diode being optically coupled with the ends of an optical fiber.

Mixed broadband optical fiber amplifier

Abstract: The utility model relates to a hybrid broadband fiber amplifier. The signal light passes through a Raman fiber amplifier (FRA), a fixed optical filter and an erbium doped fiber amplifier (EDFA) to achieve the C+L-band (1530 nm-1610nm) broadband amplification. The FRA is mainly used to enlarge the L-band (1570 nm-1610nm) and the EDFA is mainly used to magnify the C-band (1530 nm-1560nm). A fixed optical filter is cascade connected between the two fiber amplifiers so as to smooth the gain in the signal-band. The control unit respectively controls the pumped laser array used for pumping the FRA and the pumped laser used for pumping the EDFA according to the receiving array of p-i-n pipe and the residual incentive optical power of FRA and EDFA both of which is received by the p-i-n pipe to make the gain spectrum in the signal-band smooth more easily.

Optical communications system

Abstract: For an optical communication system with wavelength-division multiplex, an optical amplifier arrangement is proposed in which one wavelength-selective coupler is arranged in each case before and after an optical amplifier and the second output optical fibres of the couplers are connected to one another. Signal components at the operating wavelength of the amplifier are supplied to the latter via the couplers while signal components at other wavelengths pass via a bypass line between the two outputs of the couplers.

Semiconductor lasers for quantum sensing

Abstract: Semiconductor lasers can be used simultaneously as optical sources and optical sensors, as they are extremely sensitive to a small amount of coherent optical feedback. We present a survey on experimental results on optical feedback in semiconductor lasers and on different approaches to describe its effect on the laser properties. We show that for long and moderate long external cavities (hundreds of meters down to centimeters) the Lang-Kobayashi delay model, multiple delays and multimode delay rate equation models are in very good agreement with experiments on edge emitting lasers (EELs) and vertical-cavity surface-emitting lasers (VCSELs). We present examples of frequency and polarization mode hopping, periodic and quasiperiodic behavior, different routes to chaos, regular pulse packages, high frequency pulsations and stochastic and coherence resonance, that all have been experimentally and numerically demonstrated. Suitable models for studying laser diodes subject to optical feedback from extremely short external cavity, or ESEC (of the order of the wavelength) are the composite cavity and the multimode butt coupling models that either consider the field amplitudes after multiple reflections in the external cavity (EC) as stationary or treat the whole compound cavity at once. Numerical and experimental studies showed that optical feedback in ESEC leads to detectable change of the laser output power or the voltage drop over the laser for a small change of either the phase or the optical feedback strength. As an example, we discuss experimental and numerical results on spectral and polarization properties of VCSELs subject of insensitive optical feedback from ESEC. The wavelength and the current of polarization switching between the two linearly polarized fundamental modes of the VCSEL are periodically modulated with the external cavity length. High contrast polarization switching is thus possible for quarter-wavelength change of external cavity length. In the case of EEL we experimentally demonstrate that with changing the length of the EC the emitted power, the wavelength and the laser voltage are periodically modulated. We explain the longitudinal mode-hopping between the neighboring composite cavity modes followed by large jumps at the external cavity frequency splitting as a result of the spectral modulation of the effective losses of the composite cavity system.