Suppression of feedback-induced noise in short-cavity V-channeled substrate inner stripe lasers with self-oscillation

Abstract

Self-oscillations of V-channeled substrate inner stripe (VSIS) lasers with index guiding and the influence of external feedback on low-frequency noise generation are presented. The self-oscillation is induced by means of shortening a cavity length of VSIS laser to 110 μm. VSIS lasers with self-oscillation have the fundamental linewidth of 0.56 Å below 3 mW and are not sensitive to both phase and amplitude of the externally reflected light. Signal to noise ratio of short-cavity VSIS laser at 1 MHz with a 10-KHz bandwidth was 97 dB at 0.05% optical feedback.

Self-Pulsation Dynamics in Narrow Stripe Semiconductor Lasers

“…The laser diodes are designed so that the lateral electromagnetic field extends from an electrically pumped region of the stripe layer to unpumped regions on either side which act as saturable absorber sections. Lateral charge carrier transport effects in the nonuniformly pumped stripe layers would, therefore, play a strong role since it is well known that they affect the damping of relaxation oscillations in bulk active region lasers [24]- [27] and quantum-well structures [28]. In our previous work, however, it was shown that strongly temperature-dependent effects (such as charge carrier diffusion) do not play a key role in the pulse generation in the CD lasers [29], [30].…”

Self-pulsation in an InGaN laser-theory and experiment

“…Since the active and SA layers are separated by an evaporation-preventing layer, we assume different carrier lifetimes in the active region and in the SA. Our treatment differs from previous ones [9], [10], where the SA and the active regions are The theoretical model used in this paper originates from Yamada [14], [15]. The rate equations of laser operation are (1) (2) where is the photon number, is the injected carrier number in the the region, is the differential gain coefficient, is the field confinement factor, is the transparent carrier number, is the carrier lifetime, and is an equivalent lifetime giving the carrier diffusion from to region.…”

Reduction of Intensity Noise in Semiconductor Lasers by Simultaneous Usage of the Superposition of High Frequency Current and the Electric Negative Feedback

“…The semiconductor lasers tend to generate excess intensity noise, so-called the optical feedback noise, which is induced by reinjection of the output light into the laser by reflection at the surface of connecting optical devices, as well as the quantum noise which is caused by intrinsic fluctuations on the electron and photon numbers [1], [2]. The optical feedback noise can be suppressed by superposition of the HF (High Frequency) current [3] or by utilization of the selfpulsation laser [4]. However, in some cases the noise can not reduce sufficiently only by these reduction methods [5], [6].…”