Filters & Lasers Technology
Solid fundamentals, critical innovations

tunable filter etalonCharles Fabry and Alfred Perot coined the term etalon (a standard of weight or measure) to describe an optical cavity between two reflecting surfaces. Micron Optics has added a single segment of optical fiber within the original Fabry-Perot etalon and developed and patented a fiber Fabry-Perot (FFP) tunable filter. This all-fiber etalon contains no lenses or collimating optics and constitutes Micron Optics' FFP Technology. All the powerful fundamental characteristics of the original invention is preserved, but with three critical advanced technical attributes: 

  • Micron Optics' FFP Technology has superior beam guiding technique within the cavity. The extreme alignment, temperature, and vibration sensitivities of the "old", bulk-optic Fabry-Perot interferometers are gone.
  • Micron Optics' FFP Technology has natural fiber connection compatibility unlike lenses or integrated waveguides, which encounter fundamental connection difficulties. The FFP platform is in the ranks of other commercial successful all-fiber components, including fiber couplers, Erbium-doped fiber amplifiers (EDFAs), and fiber Bragg gratings (FBGs).
  • Micron Optics' FFP Technology is combined with the highest resolution mechanical positioning devices, Piezoelectric Transducers (i.e., PZTs), to position the mirrors in Micron Optics' FFPs. PZTs are used in atomic force microscopes to position elements to subatomic dimensions. This level of mechanical resolution ensures stable, smooth, repeatable tuning of any FFP filter.

These three critical innovations allow the FFP optical response to truly follow the Airy function from the top of its low-loss peak down to the very bottom of its stop band, and to be smoothly and precisely controlled over all points in between.

Why filter response is so critical

Airy Function

The shape of any filter response defines its performance characteristics. The high degree to which the Micron Optics FFP Technology follows the Airy Function theory means optical systems can be designed to exhibit extremely low loss, predictable cross-talk, highly accurate power measurements, high Optical Signal to Noise Ratio (OSNR), and excellent wavelength resolution.

Micron Optics' FFP tunable filters show distinct advantages over competitive Fabry-Perot technology, including excellent linearity and contrast characteristics as shown to the right.

 

Micron Optics' Fiber Fabry-Perot Technology

Features:
  • Wide tuning range
  • High finesse
  • High resolution
  • Low loss
  • High contrast
  • Low reflection loss
  • Excellent Airy transmission profile
  • High power handling ability
  • High speed
  • Precise locking/tracking capability
  • Excellent thermal stability
  • Excellent mechanical stability
  • High reliability, field tested
  • Telecordia qualified: < 80 FITs
Advantages:
  • Enables the highest performance optical channel analyzer in WDM telecom systems.
  • Enables the designs of versatile tunable and swept laser systems.
  • Exhibits rapid tuning and locking capabilities, enabling channel selection and dropping applications in dynamic optical networks.
  • Is used in telecom systems around the world for optical noise filtering and dynamic channel locking, and has demonstrated extremely high reliability (<80 FITS).
  • Enables rapid optical component testing and spectrum analysis with wide dynamic range and high accuracy.
Standard Vinesse Values
Fig.3. (a) Transmission characteristics for a range of cavity finesse values with a fixed FSR
Various FSRs
 Fig.3. (b) Transmission characteristics of various FSRs with the same bandwidth

Swept Laser Systems Based on FFP-TF Technology

SOAAs illustrated in the figure to the right, the core of the Micron Optics' high-speed swept laser incorporates a Semiconductor Optical Amplifier (SOA,) a high-performance FFP-TF, and the associated isolators and couplers to form a uni-directional ring laser. This unique design embodies the collective advantages of the SOA's broad gain-bandwidth with direct modulation capability, and the Micron Optics FFP-TF's wide tuning ranges (i.e., free spectral range (FSR) > 200nm), high finesse (1000 to 10,000), low loss (<2dB), and fast scan rates reaching beyond 45KHz to provide rapid wavelength scanning operations. As a result, the laser can sweep beyond 100nm in micro-seconds range, output a scanning peak power in the milliwatt level, and exhibit excellent peak signal-to-spontaneous-emission ratio (SSE) >80dB.

When configured as a seed laser followed by post amplification, the swept spectrum and power can be optimized for high-sensitivity imaging, remote sensing, and nonlinear wavelength conversion applications. Furthermore, when combined with a dispersive element, the wavelength sweep can be converted into high-speed and wide-angle spatial scanning without moving parts. Depending on applications, the laser generally needs to be optimized to meet varying combinations of requirements including the sweep range, linewidth, power, speed, and center wavelength.

Swept Laser Technology Platform Comparison

key performance table

 Micron Optics Technology -- Higher Imaging Performance and Commercialization Capability

FEATURED CASE STUDIES