Anthony Klee

Characterization of Semiconductor-Based Optical Frequency Comb Sources Using Generalized Multiheterodyne Detection

A spectrally efficient multiheterodyne scheme is applied for the independent measurement of the spectral phase profiles of three distinct semiconductor frequency combs. The amount of quadratic and cubic phase is quantified for each source, providing insight on the dispersive properties of the semiconductor gain and the fiberized laser cavity. This information is vital for the optimization and expansion of the spectral bandwidth of such sources.

Generalized Spectral Magnitude and Phase Retrieval Algorithm for Self-Referenced Multiheterodyne Detection

An algorithm for self-referenced spectral magnitude and phase retrieval of both optical frequency combs from a dual-comb multiheterodyne interferogram is rigorously defined. The algorithm is generalized to allow for the repetition rates of the two combs to be significantly different which allows for a reduction in required RF bandwidth. The validity of the algorithm is confirmed with an experimental demonstration.

Injection-locked VCSEL arrays for line-by-line pulse-shaping with update times of less than 1 ns

Dynamic and static optical pulse shaping with line-by-line control is shown, using a 12-channel injection-locked VCSEL linear array. With channel modulation frequencies up to 3.125 GHz, pulse shape changes within 1 ns are conclusively demonstrated.

Line-by-Line Pulse-Shaping at GHz Modulation Frequencies With an Injection-Locked VCSEL Array

A 12-channel linear vertical-cavity surface-emitting laser (VCSEL) array emitting at ~1540 nm is used as a modulator array for rapid-update ultrashort pulse shaping. Each VCSEL is injection locked with an individual comb line from a 12.5-GHz optical frequency comb. Pulse shaping is achieved by modulating the current to each VCSEL. Two regimes are demonstrated: 1) static pulse shapes, where the dc bias to the array is set to generate some of the canonical pulse shapes and 2) dynamic pulse shapes, where the currents to the array are modulated at frequencies up to 3.125 GHz, and the resultant pulse shapes change on a sub-ns timescale.

Semiconductor laser based optical frequency combs — Applications in communications and signal processing

Optical frequency combs from mode-locked lasers are developed and used for realizing unique functionality for applications in ultra-wide bandwidth communication and signal processing.

Broadband, low noise modelocked semiconductor laser with intracavity programmable dispersion control

An intracavity pulseshaper is used to broaden the spectrum of a 10 GHz semiconductor frequency comb to greater than 28 nm. Timing jitter is measured to be 15.4 fs integrated from 1 kHz to 100 MHz offset.

Optical frequency combs from mode-locked diode lasers - applications in communications, signal processing & radar for avionics

Optical frequency combs from mode-locked lasers are developed and used for realizing unique functionality for applications in ultra-wide bandwidth communication and signal processing.

Accurate Self-Referenced Retrieval Algorithm for Dual-Comb Metrology

An improved algorithm for the self-referenced retrieval of an optical frequency combs spectral magnitude and phase from a dual-comb interferogram is presented. The interferogram’s fourier spectrum is repetitively sparsely sampled to increase retrieval accuracy.

Multiheterodyne detection for self-referenced characterization of complex arbitrary waveforms from largely detuned optical frequency combs

Recently, it has been demonstrated that by considering a larger portion of the RF comb, a self-referenced measurement of each optical comb can be recovered, thus eliminating the need for a known reference with flat phase. In this manuscript, a more general form of this technique is explored, in which the mode spacings of the two unknown comb sources are detuned from each other by a factor of two or greater. This is a case of interest, seeing as how arbitrary waveforms generated from spectral modulation of OFCs which one might wish to characterize regularly exceed 10s of GHz rates, whereas the self-referenced, carrier-envelope offset stabilized sources which provide absolute knowledge of the optical frequencies involved in the multiheterodyne process are most commonly found in the sub-GHz repetition rate regime.

Direct comparison of semiconductor and erbium-based frequency stabilized harmonically mode-locked lasers

We compare the performance of two optical frequency comb sources containing intra-cavity Fabry-Perot etalons but differing gain media. Both 10 GHz harmonically mode-locked, fiberized lasers are stabilized via the etalon and active feedback.