An Efficient Wavelength Converter Exploiting a Grating-Based Saw-Tooth Pulse Shaper

Abstract

Abstract-We experimentally demonstrate the generation of picosecond triangular optical pulses using a superstructured fiber Bragg grating and show experimentally that use of this pulse shape can provide a three-fold improvement in conversion efficiency relative to the use of Gaussian pulses with similar pulsewidths when used in a wavelength conversion scheme based on self-phase modulation and subsequent offset filtering.Index Terms-Fiber Bragg grating, highly nonlinear fiber (HNLF), optical Kerr effect, optical pulse shaping, self-phase modulation (SPM).

Impact of initial pulse shape on the nonlinear spectral compression in optical fibre

“…3(a)), and the two parts of the spectrum separate in frequency, as demonstrated in [27,28] where the spectral doubling of an optical signal by the SPM or XPM phase shift generated by a triangular pulse has been investigated. A natural extension of this analysis would include the use of saw-tooth pulses, where the asymmetry of the intensity profile would cause one portion of the spectrum to evolve at a higher rate than the other [29]. We would like to emphasize that the spectral dynamics of the triangular pulse can be interpreted in terms of the well-known Fresnel bi-prism interference [30], which is widely taught in university textbooks [31,32].…”

Advanced optical processing systems combining linear pulse shapers and fibre-based nonlinear switches

“…The asymmetry in the temporal profile of the saw-tooth pulses gives rise to distinct spectral features on either side of the central wavelength (Fig.3b) -see discussion in Ref. [3]. The sharp trailing edge of the pulses gives rise to a broad range of new frequencies extending on the short-wavelength side of the spectrum.…”

“…The generation of rectangular [1], parabolic [2] or even saw-tooth shaped [3] ps-long pulses using this technique has already been demonstrated.…”

“…It is recognised however, that in most applications it is the control signal which is pre-shaped; this is both because this is usually the most crucial signal for the operation of the switch, and also because this is typically a locally generated signal with well-controlled characteristics. In order to appreciate more easily the significance of pulse shaping in these applications, we will investigate a simple example which studies the nonlinear propagation of two different pulse shapes in the same length of HNLF [3]. The fibre has a nonlinear coefficient of 19…”

Time domain add–drop multiplexing scheme enhanced using a saw-tooth pulse shaper

“…This is achieved by overlapping the leading (trailing) edge of the control pulse with the (much shorter) OTDM data pulse, imposing a red (blue) shift upon its spectrum. The extent of the frequency-shift is proportional to the intensity gradient experienced by each data bit due to its interaction with the control pulse [6]. The drop function of the OTDM tributary is achieved by spectrally filtering the wavelength-shifted component.…”