摘要:
This invention relates to invention relates to a variable slope optical filter in the form of a Fabry-Perôt etalon having an end face with a variable finesse. A method for filtering and a variable slope optical filter for in-line use with an optical amplifier signal is also disclosed. The filter has a wavelength response that is substantially linear in slope within a band of operation wavelengths of the amplifier; the slope of the filter in an operating band of wavelengths is between zero and a only one of a positive or negative number; furthermore the filter has an amplitude response that has an opposite and counter slope as a function of wavelength to that of a gain tilt of the amplifier within the operation band of wavelengths. Relative movement between the filter and the optical amplifier signal is provided to vary the slope of the filter by means of varying the amplitude wavelength response of the filter.
摘要:
A multi-mode interference coupler is disclosed for coupling light between ports. The MMI coupler is a planar waveguide having a first input port for launching light into a core of the planar waveguide which has first refractive index n 1 . The waveguide is dimensioned to have a response that confines light launched therein to a single mode in one dimension, and multi-mode in another dimension. Two other ports are provided for receiving light launched into and propagating through the core from the input port. A polymer cladding of a second material having a refractive index n 2 covers at least a portion of the core. A heater is provided and is thermally coupled to the cladding for heating the cladding when a control signal is applied.
摘要:
A low optical loss and high efficiency grating is placed within a broad-area high-power laser diode or single spatial mode laser diode to narrow the spectral width and stabilize the emission wavelength. Several embodiments of grating configurations are presented, together with the measured results of a reduction to practice of a particular embodiment.
摘要:
A micro-electro-mechanical (MEMs) mirror device for use in an optical switch is disclosed. A "piano"-style MEMs device includes an elongated platform pivotally mounted proximate the middle thereof by a torsional hinge. The middle portion of the platform and the torsional hinge have a combined width less than the width of the rest of the platform, whereby several of these "piano" MEMs devices can be positioned adjacent each other pivotally mounted about the same axis with only a relatively small air gap therebetween. In a preferred embodiment of the present invention specially designed for wavelength switching applications, a greater range of arcuate motion for a mirror mounted thereon is provided by enabling the platform to rotate about two perpendicular axes. The MEMs mirror device according to the preferred embodiment of the present invention enables the mirror to tilt about two perpendicular axes, by the use of an "internal" gimbal ring construction, which ensures that a plurality of adjacent mirror devices have a high fill factor, without having to rely on complicated and costly manufacturing processes.
摘要:
The present invention relates to an in-line optical amplifier that can be coupled to optical fibre, wherein the amplifying medium (22;44) has a substantially larger mode field than the optical fibre (20) to which it is coupled. The present invention has realized a design to utilize a very high power pump launching a multimoded signal having approximately 1W of pump power into a block (22;44) of erbium doped glass having a mode field diameter orders of magnitude larger than the mode field diameter of erbium doped fibre. By using a block of glass having a rare earth therein, packaging, temperature stabilizing and temperature tuning of the amplifier also become practicable. Furthermore, a cylindrical block of glass having planar ends, lends itself to applying coatings or filters (52;54) thereto, thereby forming selective filters at ends of the erbium doped block to allow the pump light in, and the signal light in at opposite ends, while preventing light at the pump wavelength to propagate out with the amplified signal.
摘要:
Apparatus for modifying the optical characteristics of an optical fiber by controlled stretching of a length of the fiber, comprising a first fiber holder (16) fixedly carried by a base (10) and capable of firmly holding a first portion of the optical fiber, a lever part (14) attached to the base at a fulcrum (12), and second fiber holder (18) movably connected to the lever part and capable of firmly holding a second portion of the fiber, so that an intermediate length of the fiber may be held taut between said first and second holding means. An electromagnetic circuit (22,23) moves the lever part between first and second predetermined positions, so that the intermediate length of fiber is stretched as the lever part moves between first and second positions. Preferably, the intermediate length of fiber includes a Bragg grating (20).
摘要:
A circuit for de-interleaving or interleaving multichannel optical signals having a predetermined inter-channel frequency spacing, uses a plurality of sequentially coupled periodic filters of a similar free spectral range, for example Fabry-Perot etalon-based interleavers/de-interleavers. The spectral response of the consecutive filters is shifted to accommodate different channel groupings. The free-spectral range of each of the interleavers is similar and the channel period is larger than two adjacent inter-channel frequency spacings of an input optical signal.